Kalanit Grill-Spector

All Publications

• A practical guide for combining functional regions of interest and white matter bundles. Frontiers in neuroscience Meisler, S. L., Kubota, E., Grotheer, M., Gabrieli, J. D., Grill-Spector, K. 2024; 18: 1385847

  Abstract

  Diffusion-weighted imaging (DWI) is the primary method to investigate macro- and microstructure of neural white matter in vivo. DWI can be used to identify and characterize individual-specific white matter bundles, enabling precise analyses on hypothesis-driven connections in the brain and bridging the relationships between brain structure, function, and behavior. However, cortical endpoints of bundles may span larger areas than what a researcher is interested in, challenging presumptions that bundles are specifically tied to certain brain functions. Functional MRI (fMRI) can be integrated to further refine bundles such that they are restricted to functionally-defined cortical regions. Analyzing properties of these Functional Sub-Bundles (FSuB) increases precision and interpretability of results when studying neural connections supporting specific tasks. Several parameters of DWI and fMRI analyses, ranging from data acquisition to processing, can impact the efficacy of integrating functional and diffusion MRI. Here, we discuss the applications of the FSuB approach, suggest best practices for acquiring and processing neuroimaging data towards this end, and introduce the FSuB-Extractor, a flexible open-source software for creating FSuBs. We demonstrate our processing code and the FSuB-Extractor on an openly-available dataset, the Natural Scenes Dataset.

  View details for DOI 10.3389/fnins.2024.1385847

  View details for PubMedID 39221005

  View details for PubMedCentralID PMC11363198

• Rethinking simultaneous suppression in visual cortex via compressive spatiotemporal population receptive fields. Nature communications Kupers, E. R., Kim, I., Grill-Spector, K. 2024; 15 (1): 6885

  Abstract

  When multiple visual stimuli are presented simultaneously in the receptive field, the neural response is suppressed compared to presenting the same stimuli sequentially. The prevailing hypothesis suggests that this suppression is due to competition among multiple stimuli for limited resources within receptive fields, governed by task demands. However, it is unknown how stimulus-driven computations may give rise to simultaneous suppression. Using fMRI, we find simultaneous suppression in single voxels, which varies with both stimulus size and timing, and progressively increases up the visual hierarchy. Using population receptive field (pRF) models, we find that compressive spatiotemporal summation rather than compressive spatial summation predicts simultaneous suppression, and that increased simultaneous suppression is linked to larger pRF sizes and stronger compressive nonlinearities. These results necessitate a rethinking of simultaneous suppression as the outcome of stimulus-driven compressive spatiotemporal computations within pRFs, and open new opportunities to study visual processing capacity across space and time.

  View details for DOI 10.1038/s41467-024-51243-7

  View details for PubMedID 39128923

  View details for PubMedCentralID PMC11317513

• Both mOTS-words and pOTS-words prefer emoji stimuli over text stimuli during a lexical judgment task. Cerebral cortex (New York, N.Y. : 1991) Dalski, A., Kular, H., Jorgensen, J. G., Grill-Spector, K., Grotheer, M. 2024; 34 (8)

  Abstract

  The visual word form area in the occipitotemporal sulcus (here OTS-words) is crucial for reading and shows a preference for text stimuli. We hypothesized that this text preference may be driven by lexical processing. Hence, we performed three fMRI experiments (n = 15), systematically varying participants' task and stimulus, and separately evaluated middle mOTS-words and posterior pOTS-words. Experiment 1 contrasted text with other visual stimuli to identify both OTS-words subregions. Experiment 2 utilized an fMRI adaptation paradigm, presenting compound words as texts or emojis. In experiment 3, participants performed a lexical or color judgment task on compound words in text or emoji format. In experiment 2, pOTS-words, but not mOTS-words, showed fMRI adaptation for compound words in both formats. In experiment 3, both subregions showed higher responses to compound words in emoji format. Moreover, mOTS-words showed higher responses during the lexical judgment task and a task-stimulus interaction. Multivariate analyses revealed that distributed responses in pOTS-words encode stimulus and distributed responses in mOTS-words encode stimulus and task. Together, our findings suggest that the function of the OTS-words subregions goes beyond the specific visual processing of text and that these regions are flexibly recruited whenever semantic meaning needs to be assigned to visual input.

  View details for DOI 10.1093/cercor/bhae339

  View details for PubMedID 39191663

• White matter connections of human ventral temporal cortex are organized by cytoarchitecture, eccentricity, and category-selectivity from birth. bioRxiv : the preprint server for biology Kubota, E., Yan, X., Tung, S., Fascendini, B., Tyagi, C., Duhameau, S., Ortiz, D., Grotheer, M., Natu, V. S., Keil, B., Grill-Spector, K. 2024

  Abstract

  Category-selective regions in ventral temporal cortex (VTC) have a consistent anatomical organization, which is hypothesized to be scaffolded by white matter connections. However, it is unknown how white matter connections are organized from birth. Here, we scanned newborn to 6-month-old infants and adults and used a data-driven approach to determine the organization of the white matter connections of VTC. We find that white matter connections are organized by cytoarchitecture, eccentricity, and category from birth. Connectivity profiles of functional regions in the same cytoarchitectonic area are similar from birth and develop in parallel, with decreases in endpoint connectivity to lateral occipital, and parietal, and somatosensory cortex, and increases to lateral prefrontal cortex. Additionally, connections between VTC and early visual cortex are organized topographically by eccentricity bands and predict eccentricity biases in VTC. These data have important implications for theories of cortical functional development and open new possibilities for understanding typical and atypical white matter development.

  View details for DOI 10.1101/2024.07.29.605705

  View details for PubMedID 39131283

  View details for PubMedCentralID PMC11312531

• A unifying framework for functional organization in early and higher ventral visual cortex. Neuron Margalit, E., Lee, H., Finzi, D., DiCarlo, J. J., Grill-Spector, K., Yamins, D. L. 2024

  Abstract

  A key feature of cortical systems is functional organization: the arrangement of functionally distinct neurons in characteristic spatial patterns. However, the principles underlying the emergence of functional organization in the cortex are poorly understood. Here, we develop the topographic deep artificial neural network (TDANN), the first model to predict several aspects of the functional organization of multiple cortical areas in the primate visual system. We analyze the factors driving the TDANN's success and find that it balances two objectives: learning a task-general sensory representation and maximizing the spatial smoothness of responses according to a metric that scales with cortical surface area. In turn, the representations learned by the TDANN are more brain-like than in spatially unconstrained models. Finally, we provide evidence that the TDANN's functional organization balances performance with between-area connection length. Our results offer a unified principle for understanding the functional organization of the primate ventral visual system.

  View details for DOI 10.1016/j.neuron.2024.04.018

  View details for PubMedID 38733985

• High-resolution myelin-water fraction and quantitative relaxation mapping using 3D ViSTa-MR fingerprinting. Magnetic resonance in medicine Liao, C., Cao, X., Iyer, S. S., Schauman, S., Zhou, Z., Yan, X., Chen, Q., Li, Z., Wang, N., Gong, T., Wu, Z., He, H., Zhong, J., Yang, Y., Kerr, A., Grill-Spector, K., Setsompop, K. 2023

  Abstract

  This study aims to develop a high-resolution whole-brain multi-parametric quantitative MRI approach for simultaneous mapping of myelin-water fraction (MWF), T1 , T2 , and proton-density (PD), all within a clinically feasible scan time.We developed 3D visualization of short transverse relaxation time component (ViSTa)-MRF, which combined ViSTa technique with MR fingerprinting (MRF), to achieve high-fidelity whole-brain MWF and T1 /T2 /PD mapping on a clinical 3T scanner. To achieve fast acquisition and memory-efficient reconstruction, the ViSTa-MRF sequence leverages an optimized 3D tiny-golden-angle-shuffling spiral-projection acquisition and joint spatial-temporal subspace reconstruction with optimized preconditioning algorithm. With the proposed ViSTa-MRF approach, high-fidelity direct MWF mapping was achieved without a need for multicompartment fitting that could introduce bias and/or noise from additional assumptions or priors.The in vivo results demonstrate the effectiveness of the proposed acquisition and reconstruction framework to provide fast multi-parametric mapping with high SNR and good quality. The in vivo results of 1 mm- and 0.66 mm-isotropic resolution datasets indicate that the MWF values measured by the proposed method are consistent with standard ViSTa results that are 30× slower with lower SNR. Furthermore, we applied the proposed method to enable 5-min whole-brain 1 mm-iso assessment of MWF and T1 /T2 /PD mappings for infant brain development and for post-mortem brain samples.In this work, we have developed a 3D ViSTa-MRF technique that enables the acquisition of whole-brain MWF, quantitative T1 , T2 , and PD maps at 1 and 0.66 mm isotropic resolution in 5 and 15 min, respectively. This advancement allows for quantitative investigations of myelination changes in the brain.

  View details for DOI 10.1002/mrm.29990

  View details for PubMedID 38156945

• High-resolution myelin-water fraction and quantitative relaxation mapping using 3D ViSTa-MR fingerprinting. ArXiv Liao, C., Cao, X., Srinivasan Iyer, S., Schauman, S., Zhou, Z., Yan, X., Chen, Q., Li, Z., Wang, N., Gong, T., Wu, Z., He, H., Zhong, J., Yang, Y., Kerr, A., Grill-Spector, K., Setsompop, K. 2023

  Abstract

  This study aims to develop a high-resolution whole-brain multi-parametric quantitative MRI approach for simultaneous mapping of myelin-water fraction (MWF), T1, T2, and proton-density (PD), all within a clinically feasible scan time.We developed 3D ViSTa-MRF, which combined Visualization of Short Transverse relaxation time component (ViSTa) technique with MR Fingerprinting (MRF), to achieve high-fidelity whole-brain MWF and T1/T2/PD mapping on a clinical 3T scanner. To achieve fast acquisition and memory-efficient reconstruction, the ViSTa-MRF sequence leverages an optimized 3D tiny-golden-angle-shuffling spiral-projection acquisition and joint spatial-temporal subspace reconstruction with optimized preconditioning algorithm. With the proposed ViSTa-MRF approach, high-fidelity direct MWF mapping was achieved without a need for multi-compartment fitting that could introduce bias and/or noise from additional assumptions or priors.The in-vivo results demonstrate the effectiveness of the proposed acquisition and reconstruction framework to provide fast multi-parametric mapping with high SNR and good quality. The in-vivo results of 1mm- and 0.66mm-iso datasets indicate that the MWF values measured by the proposed method are consistent with standard ViSTa results that are 30x slower with lower SNR. Furthermore, we applied the proposed method to enable 5-minute whole-brain 1mm-iso assessment of MWF and T1/T2/PD mappings for infant brain development and for post-mortem brain samples.In this work, we have developed a 3D ViSTa-MRF technique that enables the acquisition of whole-brain MWF, quantitative T1, T2, and PD maps at 1mm and 0.66mm isotropic resolution in 5 and 15 minutes, respectively. This advancement allows for quantitative investigations of myelination changes in the brain.

  View details for DOI 10.1016/j.neuroimage.2018.04.017

  View details for PubMedID 38196746

  View details for PubMedCentralID PMC10775347

• Longitudinal development of category representations in ventral temporal cortex predicts word and face recognition. Nature communications Nordt, M., Gomez, J., Natu, V. S., Rezai, A. A., Finzi, D., Kular, H., Grill-Spector, K. 2023; 14 (1): 8010

  Abstract

  Regions in ventral temporal cortex that are involved in visual recognition of categories like words and faces undergo differential development during childhood. However, categories are also represented in distributed responses across high-level visual cortex. How distributed category representations develop and if this development relates to behavioral changes in recognition remains largely unknown. Here, we used functional magnetic resonance imaging to longitudinally measure the development of distributed responses across ventral temporal cortex to 10 categories in school-age children over several years. Our results reveal both strengthening and weakening of category representations with age, which was mainly driven by changes across category-selective voxels. Representations became particularly more distinct for words in the left hemisphere and for faces bilaterally. Critically, distinctiveness for words and faces across category-selective voxels in left and right lateral ventral temporal cortex, respectively, predicted individual children's word and face recognition performance. These results suggest that the development of distributed representations in ventral temporal cortex has behavioral ramifications and advance our understanding of prolonged cortical development during childhood.

  View details for DOI 10.1038/s41467-023-43146-w

  View details for PubMedID 38049393

  View details for PubMedCentralID 4856551

• Characterizing spatiotemporal population receptive fields in human visual cortex with fMRI. The Journal of neuroscience : the official journal of the Society for Neuroscience Kim, I., Kupers, E. R., Lerma-Usabiaga, G., Grill-Spector, K. 2023

  Abstract

  The use of fMRI and computational modeling has advanced understanding of spatial characteristics of population receptive fields (pRFs) in human visual cortex. However, we know relatively little about the spatiotemporal characteristics of pRFs because neurons' temporal properties are one to two orders of magnitude faster than fMRI BOLD responses. Here, we developed an image-computable framework to estimate spatiotemporal pRFs from fMRI data. First, we developed a simulation software that predicts fMRI responses to a time-varying visual input given a spatiotemporal pRF model and solves the model parameters. The simulator revealed that ground-truth spatiotemporal parameters can be accurately recovered at the millisecond resolution from synthesized fMRI responses. Then, using fMRI and a novel stimulus paradigm, we mapped spatiotemporal pRFs in individual voxels across human visual cortex in 10 participants (both females and males). We find that a compressive spatiotemporal (CST) pRF model better explains fMRI responses than a conventional spatial pRF model across visual areas spanning the dorsal, lateral, and ventral streams. Further, we find three organizational principles of spatiotemporal pRFs: (i) from early to later areas within a visual stream, spatial and temporal windows of pRFs progressively increase in size and show greater compressive nonlinearities, (ii) later visual areas show diverging spatial and temporal windows across streams, and (iii) within early visual areas (V1-V3), both spatial and temporal windows systematically increase with eccentricity. Together, this computational framework and empirical results open exciting new possibilities for modeling and measuring fine-grained spatiotemporal dynamics of neural responses using fMRI.Significance Statement We developed a computational framework for estimating spatiotemporal receptive fields of neural populations using fMRI. This framework pushes the boundary of fMRI measurements, enabling quantitative evaluation of neural spatial and temporal processing windows at the resolution of visual degrees and milliseconds, which was thought to be unattainable with fMRI. We not only replicate well-established visual field and pRF size maps, but also estimates of temporal windows from electrophysiology and electrocorticography. Notably, we find that spatial and temporal windows as well as compressive nonlinearities progressively increase from early to later visual areas in multiple visual processing streams. Together, this framework opens exciting new possibilities for modeling and measuring fine-grained spatiotemporal dynamics of neural responses in the human brain using fMRI.

  View details for DOI 10.1523/JNEUROSCI.0803-23.2023

  View details for PubMedID 37963768

• Both mOTS-words and pOTS-words prefer emoji stimuli over text stimuli during a reading task. bioRxiv : the preprint server for biology Dalski, A., Kular, H., Jorgensen, J. G., Grill-Spector, K., Grotheer, M. 2023

  Abstract

  The visual word form area in the occipitotemporal sulcus (OTS), here referred to as OTS-words, responds more strongly to text than other visual stimuli and plays a critical role in reading. Here we hypothesized, that this region's preference for text may be driven by a preference for reading tasks, as in most prior fMRI studies only the text stimuli were readable. To test this, we performed three fMRI experiments (N=15) and systematically varied the participant's task and the visual stimulus, investigating mOTS-words and pOTS-words subregions. In experiment 1, we contrasted text stimuli with non-readable visual stimuli (faces, limbs, houses, and objects). In experiment 2, we used an fMRI adaptation paradigm, presenting the same or different compound words in text or emoji formats. In experiment 3, participants performed either a reading or a color task on compound words, presented in text or emoji format. Using experiment 1 data, we identified left mOTS-words and pOTS-words in all participants by contrasting text stimuli with non-readable stimuli. In experiment 2, pOTS-words, but not mOTS-words, showed fMRI adaptation for compound words in both text and emoji formats. In experiment 3, surprisingly, both mOTS-words and pOTS-words showed higher responses to compound words in emoji than text format. Moreover, mOTS-words, but not pOTS-words, also showed higher responses during the reading than the color task as well as an interaction between task and stimulus. Multivariate analyses showed that distributed responses in pOTS-words encode the visual stimulus, whereas distributed responses in mOTS-words encode both the stimulus and the task. Together, our findings suggest that the function of the OTS-words subregions goes beyond the specific visual processing of text and that these regions are flexibly recruited whenever semantic meaning needs to be assigned to visual input.

  View details for DOI 10.1101/2023.11.07.565794

  View details for PubMedID 37986766

  View details for PubMedCentralID PMC10659328

• Rethinking cortical recycling in ventral temporal cortex. Trends in cognitive sciences Kubota, E., Grill-Spector, K., Nordt, M. 2023

  Abstract

  High-level visual areas in ventral temporal cortex (VTC) support recognition of important categories, such as faces and words. Word-selective regions are left lateralized and emerge at the onset of reading instruction. Face-selective regions are right lateralized and have been documented in infancy. Prevailing theories suggest that face-selective regions become right lateralized due to competition with word-selective regions in the left hemisphere. However, recent longitudinal studies examining face- and word-selective responses in childhood do not provide support for this theory. Instead, there is evidence that word representations recycle cortex previously involved in processing other stimuli, such as limbs. These findings call for more longitudinal investigations of cortical recycling and a new era of work that links visual experience and behavior with neural responses.

  View details for DOI 10.1016/j.tics.2023.09.006

  View details for PubMedID 37858388

• Human white matter myelinates faster in utero than ex utero. Proceedings of the National Academy of Sciences of the United States of America Grotheer, M., Bloom, D., Kruper, J., Richie-Halford, A., Zika, S., Aguilera Gonzalez, V. A., Yeatman, J. D., Grill-Spector, K., Rokem, A. 2023; 120 (33): e2303491120

  Abstract

  The formation of myelin, the fatty sheath that insulates nerve fibers, is critical for healthy brain function. A fundamental open question is what impact being born has on myelin growth. To address this, we evaluated a large (n = 300) cross-sectional sample of newborns from the Developing Human Connectome Project (dHCP). First, we developed software for the automated identification of 20 white matter bundles in individual newborns that is well suited for large samples. Next, we fit linear models that quantify how T1w/T2w (a myelin-sensitive imaging contrast) changes over time at each point along the bundles. We found faster growth of T1w/T2w along the lengths of all bundles before birth than right after birth. Further, in a separate longitudinal sample of preterm infants (N = 34), we found lower T1w/T2w than in full-term peers measured at the same age. By applying the linear models fit on the cross-section sample to the longitudinal sample of preterm infants, we find that their delay in T1w/T2w growth is well explained by the amount of time they spent developing in utero and ex utero. These results suggest that white matter myelinates faster in utero than ex utero. The reduced rate of myelin growth after birth, in turn, explains lower myelin content in individuals born preterm and could account for long-term cognitive, neurological, and developmental consequences of preterm birth. We hypothesize that closely matching the environment of infants born preterm to what they would have experienced in the womb may reduce delays in myelin growth and hence improve developmental outcomes.

  View details for DOI 10.1073/pnas.2303491120

  View details for PubMedID 37549280

• Rethinking simultaneous suppression in visual cortex via compressive spatiotemporal population receptive fields. bioRxiv : the preprint server for biology Kupers, E. R., Kim, I., Grill-Spector, K. 2023

  Abstract

  When multiple visual stimuli are presented simultaneously in the receptive field, the neural response is suppressed compared to presenting the same stimuli sequentially. The prevailing hypothesis suggests that this suppression is due to competition among multiple stimuli for limited resources within receptive fields, governed by task demands. However, it is unknown how stimulus-driven computations may give rise to simultaneous suppression. Using fMRI, we find simultaneous suppression in single voxels, which varies with both stimulus size and timing, and progressively increases up the visual hierarchy. Using population receptive field (pRF) models, we find that compressive spatiotemporal summation rather than compressive spatial summation predicts simultaneous suppression, and that increased simultaneous suppression is linked to larger pRF sizes and stronger compressive nonlinearities. These results necessitate a rethinking of simultaneous suppression as the outcome of stimulus-driven compressive spatiotemporal computations within pRFs, and open new opportunities to study visual processing capacity across space and time.

  View details for DOI 10.1101/2023.06.24.546388

  View details for PubMedID 37461470

• A Unifying Principle for the Functional Organization of Visual Cortex. bioRxiv : the preprint server for biology Margalit, E., Lee, H., Finzi, D., DiCarlo, J. J., Grill-Spector, K., Yamins, D. L. 2023

  Abstract

  A key feature of many cortical systems is functional organization: the arrangement of neurons with specific functional properties in characteristic spatial patterns across the cortical surface. However, the principles underlying the emergence and utility of functional organization are poorly understood. Here we develop the Topographic Deep Artificial Neural Network (TDANN), the first unified model to accurately predict the functional organization of multiple cortical areas in the primate visual system. We analyze the key factors responsible for the TDANN's success and find that it strikes a balance between two specific objectives: achieving a task-general sensory representation that is self-supervised, and maximizing the smoothness of responses across the cortical sheet according to a metric that scales relative to cortical surface area. In turn, the representations learned by the TDANN are lower dimensional and more brain-like than those in models that lack a spatial smoothness constraint. Finally, we provide evidence that the TDANN's functional organization balances performance with inter-area connection length, and use the resulting models for a proof-of-principle optimization of cortical prosthetic design. Our results thus offer a unified principle for understanding functional organization and a novel view of the functional role of the visual system in particular.

  View details for DOI 10.1101/2023.05.18.541361

  View details for PubMedID 37292946

  View details for PubMedCentralID PMC10245753

• Characterizing spatiotemporal population receptive fields in human visual cortex with fMRI. bioRxiv : the preprint server for biology Kim, I., Kupers, E. R., Lerma-Usabiaga, G., Grill-Spector, K. 2023

  Abstract

  The use of fMRI and computational modeling has advanced understanding of spatial characteristics of population receptive fields (pRFs) in human visual cortex. However, we know relatively little about the spatiotemporal characteristics of pRFs because neurons' temporal properties are one to two orders of magnitude faster than fMRI BOLD responses. Here, we developed an image-computable framework to estimate spatiotemporal pRFs from fMRI data. First, we developed a simulation software that predicts fMRI responses to a time varying visual input given a spatiotemporal pRF model and solves the model parameters. The simulator revealed that ground-truth spatiotemporal parameters can be accurately recovered at the millisecond resolution from synthesized fMRI responses. Then, using fMRI and a novel stimulus paradigm, we mapped spatiotemporal pRFs in individual voxels across human visual cortex in 10 participants. We find that a compressive spatiotemporal (CST) pRF model better explains fMRI responses than a conventional spatial pRF model across visual areas spanning the dorsal, lateral, and ventral streams. Further, we find three organizational principles of spatiotemporal pRFs: (i) from early to later areas within a visual stream, spatial and temporal integration windows of pRFs progressively increase in size and show greater compressive nonlinearities, (ii) later visual areas show diverging spatial and temporal integration windows across streams, and (iii) within early visual areas (V1-V3), both spatial and temporal integration windows systematically increase with eccentricity. Together, this computational framework and empirical results open exciting new possibilities for modeling and measuring fine-grained spatiotemporal dynamics of neural responses in the human brain using fMRI.Significance Statement: We developed a computational framework for estimating spatiotemporal receptive fields of neural populations using fMRI. This framework pushes the boundary of fMRI measurements, enabling quantitative evaluation of neural spatial and temporal processing windows at the resolution of visual degrees and milliseconds, which was thought to be unattainable with fMRI. We not only replicate well-established visual field and pRF size maps, but also estimates of temporal summation windows from electrophysiology. Notably, we find that spatial and temporal windows as well as compressive nonlinearities progressively increase from early to later visual areas in multiple visual processing streams. Together, this framework opens exciting new possibilities for modeling and measuring fine-grained spatiotemporal dynamics of neural responses in the human brain using fMRI.

  View details for DOI 10.1101/2023.05.02.539164

  View details for PubMedID 37205541

• Comparing retinotopic maps of children and adults reveals a late-stage change in how V1 samples the visual field. Nature communications Himmelberg, M. M., Tuncok, E., Gomez, J., Grill-Spector, K., Carrasco, M., Winawer, J. 2023; 14 (1): 1561

  Abstract

  Adult visual performance differs with angular location -it is better for stimuli along the horizontal than vertical, and lower than upper vertical meridian of the visual field. These perceptual asymmetries are paralleled by asymmetries in cortical surface area in primary visual cortex (V1). Children, unlike adults, have similar visual performance at the lower and upper vertical meridian. Do children have similar V1 surface area representing the upper and lower vertical meridian? Using MRI, we measure the surface area of retinotopic maps (V1-V3) in children and adults. Many features of the maps are similar between groups, including greater V1 surface area for the horizontal than vertical meridian. However, unlike adults, children have a similar amount of V1 surface area representing the lower and upper vertical meridian. These data reveal a late-stage change in V1 organization that may relate to the emergence of the visual performance asymmetry along the vertical meridian by adulthood.

  View details for DOI 10.1038/s41467-023-37280-8

  View details for PubMedID 36944643

• White matter connections of high-level visual areas predict cytoarchitecture better than category-selectivity in childhood, but not adulthood. Cerebral cortex (New York, N.Y. : 1991) Kubota, E., Grotheer, M., Finzi, D., Natu, V. S., Gomez, J., Grill-Spector, K. 2022

  Abstract

  Ventral temporal cortex (VTC) consists of high-level visual regions that are arranged in consistent anatomical locations across individuals. This consistency has led to several hypotheses about the factors that constrain the functional organization of VTC. A prevailing theory is that white matter connections influence the organization of VTC, however, the nature of this constraint is unclear. Here, we test 2 hypotheses: (1) white matter tracts are specific for each category or (2) white matter tracts are specific to cytoarchitectonic areas of VTC. To test these hypotheses, we used diffusion magnetic resonance imaging to identify white matter tracts and functional magnetic resonance imaging to identify category-selective regions in VTC in children and adults. We find that in childhood, white matter connections are linked to cytoarchitecture rather than category-selectivity. In adulthood, however, white matter connections are linked to both cytoarchitecture and category-selectivity. These results suggest a rethinking of the view that category-selective regions in VTC have category-specific white matter connections early in development. Instead, these findings suggest that the neural hardware underlying the processing of categorical stimuli may be more domain-general than previously thought, particularly in childhood.

  View details for DOI 10.1093/cercor/bhac221

  View details for PubMedID 35671505

• White matter myelination during early infancy is linked to spatial gradients and myelin content at birth. Nature communications Grotheer, M., Rosenke, M., Wu, H., Kular, H., Querdasi, F. R., Natu, V. S., Yeatman, J. D., Grill-Spector, K. 2022; 13 (1): 997

  Abstract

  Development of myelin, a fatty sheath that insulates nerve fibers, is critical for brain function. Myelination during infancy has been studied with histology, but postmortem data cannot evaluate the longitudinal trajectory of white matter development. Here, we obtained longitudinal diffusion MRI and quantitative MRI measures of longitudinal relaxation rate (R1) of white matter in 0, 3 and 6 months-old human infants, and developed an automated method to identify white matter bundles and quantify their properties in each infant's brain. We find that R1 increases from newborns to 6-months-olds in all bundles. R1 development is nonuniform: there is faster development in white matter that is less mature in newborns, and development rate increasesalonginferior-to-superior as well as anterior-to-posterior spatial gradients. As R1 is linearly related to myelin fraction in white matter bundles, these findings open new avenues to elucidate typical and atypical white matter myelination in early infancy.

  View details for DOI 10.1038/s41467-022-28326-4

  View details for PubMedID 35194018

• Attention enhances category representations across the brain with strengthened residual correlations to ventral temporal cortex. NeuroImage Keller, A. S., Jagadeesh, A., Bugatus, L., Williams, L. M., Grill-Spector, K. 2022: 118900

  Abstract

  How does attention enhance neural representations of goal-relevant stimuli while suppressing representations of ignored stimuli across regions of the brain? While prior studies have shown that attention enhances visual responses, we lack a cohesive understanding of how selective attention modulates visual representations across the brain. Here, we used functional magnetic resonance imaging (fMRI) while participants performed a selective attention task on superimposed stimuli from multiple categories and used a data-driven approach to test how attention affects both decodability of category information and residual correlations (after regressing out stimulus-driven variance) with category-selective regions of ventral temporal cortex (VTC). Our data reveal three main findings. First, when two objects are simultaneously viewed, the category of the attended object can be decoded more readily than the category of the ignored object, with the greatest attentional enhancements observed in occipital and temporal lobes. Second, after accounting for the response to the stimulus, the correlation in the residual brain activity between a cortical region and a category-selective region of VTC was elevated when that region's preferred category was attended vs. ignored, and more so in the right occipital, parietal, and frontal cortices. Third, we found that the stronger the residual correlations between a given region of cortex and VTC, the better visual category information could be decoded from that region. These findings suggest that heightened residual correlations by selective attention may reflect the sharing of information between sensory regions and higher-order cortical regions to provide attentional enhancement of goal-relevant information.

  View details for DOI 10.1016/j.neuroimage.2022.118900

  View details for PubMedID 35021039

• Establishing the functional relevancy of white matter connections in the visual system and beyond. Brain structure & function Grotheer, M., Kubota, E., Grill-Spector, K. 2021

  Abstract

  For over a century, researchers have examined the functional relevancy of white matter bundles. Consequently, many large-scale bundles spanning several centimeters have been associated in their entirety with specific brain functions, such as language or attention. However, these coarse structural-functional relationships are at odds with modern understanding of the fine-grained functional organization of human cortex, such as the mosaic of category-selective regions in ventral temporal cortex. Here, we review a multimodal approach that combines fMRI to define functional regions of interest within individual's brains with dMRI tractography to identify the white matter bundles of the same individual. Combining these data allows to determine which subsets of streamlines within a white matter bundle connect to specific functional regions in each individual. That is, this approach identifies the functionally defined white matter sub-bundles of the brain. We argue that this approach not only enhances the accuracy of interpreting the functional relevancy of white matter bundles, but also enables segmentation of these large-scale bundles into meaningful functional units, which can then be linked to behavior with enhanced precision. Importantly, this approach has the potential for making new discoveries of the fine-grained functional relevancy of white matter connections in the visual system and the brain more broadly, akin to the flurry of research that has identified functional regions in cortex.

  View details for DOI 10.1007/s00429-021-02423-4

  View details for PubMedID 34846595

• Infants' cortex undergoes microstructural growth coupled with myelination during development. Communications biology Natu, V. S., Rosenke, M., Wu, H., Querdasi, F. R., Kular, H., Lopez-Alvarez, N., Grotheer, M., Berman, S., Mezer, A. A., Grill-Spector, K. 2021; 4 (1): 1191

  Abstract

  Development of cortical tissue during infancy is critical for the emergence of typical brain functions in cortex. However, how cortical microstructure develops during infancy remains unknown. We measured the longitudinal development of cortex from birth to sixmonths of age using multimodal quantitative imaging of cortical microstructure. Here we show that infants' cortex undergoes profound microstructural tissue growth during the first six months of human life. Comparison of postnatal to prenatal transcriptomic gene expression data demonstrates that myelination and synaptic processes are dominant contributors to this postnatal microstructural tissue growth. Using visual cortex as a model system, we find hierarchical microstructural growth: higher-level visual areas have less mature tissue at birth than earlier visual areas but grow at faster rates. This overturns the prominent view that visual areas that are most mature at birth develop fastest. Together, in vivo, longitudinal, and quantitative measurements, which we validated with ex vivo transcriptomic data, shed light on the rate, sequence, and biological mechanisms of developing cortical systems during early infancy. Importantly, our findings propose a hypothesis that cortical myelination is a key factor in cortical development during early infancy, which has important implications for diagnosis of neurodevelopmental disorders and delays in infants.

  View details for DOI 10.1038/s42003-021-02706-w

  View details for PubMedID 34650227

• Holistic face recognition is an emergent phenomenon of spatial processing in face-selective regions. Nature communications Poltoratski, S., Kay, K., Finzi, D., Grill-Spector, K. 2021; 12 (1): 4745

  Abstract

  Spatial processing by receptive fields is a core property of the visual system. However, it is unknown how spatial processing in high-level regions contributes to recognition behavior. As face inversion is thought to disrupt typical holistic processing of information in faces, we mapped population receptive fields (pRFs) with upright and inverted faces in the human visual system. Here we show that in face-selective regions, but not primary visual cortex, pRFs and overall visual field coverage are smaller and shifted downward in response to face inversion. From these measurements, we successfully predict the relative behavioral detriment of face inversion at different positions in the visual field. This correspondence between neural measurements and behavior demonstrates how spatial processing in face-selective regions may enable holistic perception. These results not only show that spatial processing in high-level visual regions is dynamically used towards recognition, but also suggest a powerful approach for bridging neural computations by receptive fields to behavior.

  View details for DOI 10.1038/s41467-021-24806-1

  View details for PubMedID 34362883

• Cortical recycling in high-level visual cortex during childhood development. Nature human behaviour Nordt, M., Gomez, J., Natu, V. S., Rezai, A. A., Finzi, D., Kular, H., Grill-Spector, K. 2021

  Abstract

  Human ventral temporal cortex contains category-selective regions that respond preferentially to ecologically relevant categories such as faces, bodies, places and words and that are causally involved in the perception of these categories. How do these regions develop during childhood? We used functional magnetic resonance imaging to measure longitudinal development of category selectivity in school-age children over 1 to 5 years. We discovered that, from young childhood to the teens, face- and word-selective regions in ventral temporal cortex expand and become more category selective, but limb-selective regions shrink and lose their preference for limbs. Critically, as a child develops, increases in face and word selectivity are directly linked to decreases in limb selectivity, revealing that during childhood, limb selectivity in ventral temporal cortex is repurposed into word and face selectivity. These data provide evidence for cortical recycling during childhood development. This has important implications for understanding typical as well as atypical brain development and necessitates a rethinking of how cortical function develops during childhood.

  View details for DOI 10.1038/s41562-021-01141-5

  View details for PubMedID 34140657

• Differential spatial computations in ventral and lateral face-selective regions are scaffolded by structural connections. Nature communications Finzi, D., Gomez, J., Nordt, M., Rezai, A. A., Poltoratski, S., Grill-Spector, K. 2021; 12 (1): 2278

  Abstract

  Face-processing occurs across ventral and lateral visual streams, which are involved in static and dynamic face perception, respectively. However, the nature of spatial computations across streams is unknown. Using functional MRI and population receptive field (pRF) mapping, we measured pRFs in face-selective regions. Results reveal that spatial computations by pRFs in ventral face-selective regions are concentrated around the center of gaze (fovea), but spatial computations in lateral face-selective regions extend peripherally. Diffusion MRI reveals that these differences are mirrored by a preponderance of white matter connections between ventral face-selective regions and foveal early visual cortex (EVC), while connections with lateral regions are distributed more uniformly across EVC eccentricities. These findings suggest a rethinking of spatial computations in face-selective regions, showing that they vary across ventral and lateral streams, and further propose that spatial computations in high-level regions are scaffolded by the fine-grain pattern of white matter connections from EVC.

  View details for DOI 10.1038/s41467-021-22524-2

  View details for PubMedID 33859195

• White matter fascicles and cortical microstructure predict reading-related responses in human ventral temporal cortex. NeuroImage Grotheer, M., Yeatman, J., Grill-Spector, K. 2020: 117669

  Abstract

  Reading-related responses in the lateral ventral temporal cortex (VTC) show a consistent spatial layout across individuals, which is puzzling, since reading skills are acquired during childhood. Here, we tested the hypothesis that white matter fascicles and gray matter microstructure predict the location of reading-related responses in lateral VTC. We obtained functional (fMRI), diffusion (dMRI), and quantitative (qMRI) magnetic resonance imaging data in 30 adults. fMRI was used to map reading-related responses by contrasting responses in a reading task with those in adding and color tasks; dMRI was used to identify the brain's fascicles and to map their endpoints density in lateral VTC; qMRI was used to measure proton relaxation time (T1), which depends on cortical tissue microstructure. We fit linear models that predict reading-related responses in lateral VTC from endpoint density and T1 and used leave-one-subject-out cross-validation to assess prediction accuracy. Using a subset of our participants (N=10, feature selection set), we find that i) endpoint density of the arcuate fasciculus (AF), inferior longitudinal fasciculus (ILF), and vertical occipital fasciculus (VOF) are significant predictors of reading-related responses, and ii) cortical T1 of lateral VTC further improves the predictions of the fascicle model. Next, in the remaining 20 participants (validation set), we showed that a linear model that includes T1, AF, ILF and VOF significantly predicts i) the map of reading-related responses across lateral VTC and ii) the location of the visual word form area, a region critical for reading. Overall, our data-driven approach reveals that the AF, ILF, VOF and cortical microstructure have a consistent spatial relationship with an individual's reading-related responses in lateral VTC.

  View details for DOI 10.1016/j.neuroimage.2020.117669

  View details for PubMedID 33359351

• Sulcal Depth in the Medial Ventral Temporal Cortex Predicts the Location of a Place-Selective Region in Macaques, Children, and Adults. Cerebral cortex (New York, N.Y. : 1991) Natu, V. S., Arcaro, M. J., Barnett, M. A., Gomez, J., Livingstone, M., Grill-Spector, K., Weiner, K. S. 2020

  Abstract

  The evolution and development of anatomical-functional relationships in the cerebral cortex is of major interest in neuroscience. Here, we leveraged the fact that a functional region selective for visual scenes is located within a sulcus in the medial ventral temporal cortex (VTC) in both humans and macaques to examine the relationship between sulcal depth and place selectivity in the medial VTC across species and age groups. To do so, we acquired anatomical and functional magnetic resonance imaging scans in 9 macaques, 26 human children, and 28 human adults. Our results revealed a strong structural-functional coupling between sulcal depth and place selectivity across age groups and species in which selectivity was strongest near the deepest sulcal point (the sulcal pit). Interestingly, this coupling between sulcal depth and place selectivity strengthens from childhood to adulthood in humans. Morphological analyses suggest that the stabilization of sulcal-functional coupling in adulthood may be due to sulcal deepening and areal expansion with age as well as developmental differences in cortical curvature at the pial, but not the white matter surfaces. Our results implicate sulcal features as functional landmarks in high-level visual cortex and highlight that sulcal-functional relationships in the medial VTC are preserved between macaques and humans despite differences in cortical folding.

  View details for DOI 10.1093/cercor/bhaa203

  View details for PubMedID 32954410

• The structure of depressive symptoms and characteristics and their relation to overall severity in major depressive disorder. Psychiatry research Miller, C. H., Davis, E. G., King, L. S., Sacchet, M. D., Grill-Spector, K., Gotlib, I. H. 2020; 294: 113399

  Abstract

  Although many investigators have examined symptoms of major depressive disorder (MDD), the multivariate relations among these features of depression and their relative associations with overall severity of depression are not well understood. The present study is the first to examine the underlying factor structure of depression across a broad set of constructs and to model the multivariate association of these factors with the overall severity of depression. We conducted a large-scale factor analysis and multiple regression in a sample of participants diagnosed with MDD (N=233) and healthy controls (N=235). We obtained a five-factor solution composed of the following factors: (1) anxiety; (2) behavioral activation; (3) core symptoms; (4) rumination; and (5) emotional intensity. The core symptoms factor, composed primarily of DSM-5 diagnostic criteria for MDD, was the only factor that showed a consistent, significant association with overall severity of depression and functional impairment. Rumination combined with behavioral inhibition and positive and negative affect combined with each other to form coherent constructs that may be useful in examining differences among depressed individuals. These findings provide an important data-driven framework for the multidimensional symptom structure of depression and suggest several actionable ways for improving clinical assessment and treatment for individuals with MDD.

  View details for DOI 10.1016/j.psychres.2020.113399

  View details for PubMedID 33070106

• Diverse Temporal Dynamics of Repetition Suppression Revealed by Intracranial Recordings in the Human Ventral Temporal Cortex. Cerebral cortex (New York, N.Y. : 1991) Rangarajan, V., Jacques, C., Knight, R. T., Weiner, K. S., Grill-Spector, K. 2020

  Abstract

  Repeated stimulus presentations commonly produce decreased neural responses-a phenomenon known as repetition suppression (RS) or adaptation-in ventral temporal cortex (VTC) of humans and nonhuman primates. However, the temporal features of RS in human VTC are not well understood. To fill this gap in knowledge, we utilized the precise spatial localization and high temporal resolution of electrocorticography (ECoG) from nine human subjects implanted with intracranial electrodes in the VTC. The subjects viewed nonrepeated and repeated images of faces with long-lagged intervals and many intervening stimuli between repeats. We report three main findings: 1) robust RS occurs in VTC for activity in high-frequency broadband (HFB), but not lower-frequency bands; 2) RS of the HFB signal is associated with lower peak magnitude (PM), lower total responses, and earlier peak responses; and 3) RS effects occur early within initial stages of stimulus processing and persist for the entire stimulus duration. We discuss these findings in the context of early and late components of visual perception, as well as theoretical models of repetition suppression.

  View details for DOI 10.1093/cercor/bhaa173

  View details for PubMedID 32583847

• Combined Neural Tuning in Human Ventral Temporal Cortex Resolves the Perceptual Ambiguity of Morphed 2D Images. Cerebral cortex (New York, N.Y. : 1991) Rosenke, M., Davidenko, N., Grill-Spector, K., Weiner, K. S. 2020

  Abstract

  We have an amazing ability to categorize objects in the world around us. Nevertheless, how cortical regions in human ventral temporal cortex (VTC), which is critical for categorization, support this behavioral ability, is largely unknown. Here, we examined the relationship between neural responses and behavioral performance during the categorization of morphed silhouettes of faces and hands, which are animate categories processed in cortically adjacent regions in VTC. Our results reveal that the combination of neural responses from VTC face- and body-selective regions more accurately explains behavioral categorization than neural responses from either region alone. Furthermore, we built a model that predicts a person's behavioral performance using estimated parameters of brain-behavior relationships from a different group of people. Moreover, we show that this brain-behavior model generalizes to adjacent face- and body-selective regions in lateral occipitotemporal cortex. Thus, while face- and body-selective regions are located within functionally distinct domain-specific networks, cortically adjacent regions from both networks likely integrate neural responses to resolve competing and perceptually ambiguous information from both categories.

  View details for DOI 10.1093/cercor/bhaa081

  View details for PubMedID 32372098

• Ultra-high-resolution fMRI of human ventral temporal cortex reveals differential representation of categories and domains. The Journal of neuroscience : the official journal of the Society for Neuroscience Margalit, E., Jamison, K. W., Weiner, K. S., Vizioli, L., Zhang, R., Kay, K. N., Grill-Spector, K. 2020

  Abstract

  Human ventral temporal cortex (VTC) is critical for visual recognition. It is thought that this ability is supported by large-scale patterns of activity across VTC that contain information about visual categories. However, it is unknown how category representations in VTC are organized at the sub-millimeter scale and across cortical depths. To fill this gap in knowledge, we measured BOLD responses in medial and lateral VTC to images spanning ten categories from five domains (written characters, bodies, faces, places, and objects) at an ultra-high spatial resolution of 0.8 mm using 7 Tesla functional magnetic resonance imaging (fMRI) in both male and female participants. Representations in lateral VTC were organized most strongly at the general level of domains (e.g., places), whereas medial VTC was also organized at the level of specific categories (e.g., corridors and houses within the domain of places). In both lateral and medial VTC, domain-level and category-level structure decreased with cortical depth, and downsampling our data to standard resolution (2.4mm) did not reverse differences in representations between lateral and medial VTC. The functional diversity of representations across VTC partitions may allow downstream regions to read out information in a flexible manner according to task demands. These results bridge an important gap between electrophysiological recordings in single neurons at the micron scale in nonhuman primates and standard-resolution fMRI in humans by elucidating distributed responses at the submillimeter scale with ultra-high-resolution fMRI in humans.SIGNIFICANCE STATEMENTVisual recognition is a fundamental ability supported by human ventral temporal cortex (VTC). However, the nature of fine-scale, sub-millimeter distributed representations in VTC is unknown. Using ultra-high-resolution fMRI of human VTC, we found differential distributed visual representations across lateral and medial VTC. Domain representations (e.g. faces, bodies, places, characters) were most salient in lateral VTC whereas category representations (e.g., corridors/houses within the domain of places) were equally salient in medial VTC. These results bridge an important gap between electrophysiological recordings in single neurons at a micron scale and fMRI measurements at a millimeter scale.

  View details for DOI 10.1523/JNEUROSCI.2106-19.2020

  View details for PubMedID 32094202

• A Probabilistic Functional Atlas of Human Occipito-Temporal Visual Cortex. Cerebral cortex (New York, N.Y. : 1991) Rosenke, M. n., van Hoof, R. n., van den Hurk, J. n., Grill-Spector, K. n., Goebel, R. n. 2020

  Abstract

  Human visual cortex contains many retinotopic and category-specific regions. These brain regions have been the focus of a large body of functional magnetic resonance imaging research, significantly expanding our understanding of visual processing. As studying these regions requires accurate localization of their cortical location, researchers perform functional localizer scans to identify these regions in each individual. However, it is not always possible to conduct these localizer scans. Here, we developed and validated a functional region of interest (ROI) atlas of early visual and category-selective regions in human ventral and lateral occipito-temporal cortex. Results show that for the majority of functionally defined ROIs, cortex-based alignment results in lower between-subject variability compared to nonlinear volumetric alignment. Furthermore, we demonstrate that 1) the atlas accurately predicts the location of an independent dataset of ventral temporal cortex ROIs and other atlases of place selectivity, motion selectivity, and retinotopy. Next, 2) we show that the majority of voxel within our atlas is responding mostly to the labeled category in a left-out subject cross-validation, demonstrating the utility of this atlas. The functional atlas is publicly available (download.brainvoyager.com/data/visfAtlas.zip) and can help identify the location of these regions in healthy subjects as well as populations (e.g., blind people, infants) in which functional localizers cannot be run.

  View details for DOI 10.1093/cercor/bhaa246

  View details for PubMedID 32968767

• X-chromosome insufficiency alters receptive fields across the human early visual cortex. The Journal of neuroscience : the official journal of the Society for Neuroscience Green, T., Hosseini, H., Piccirilli, A., Ishak, A., Grill-Spector, K., Reiss, A. L. 2019

  Abstract

  Here, we investigated processing by receptive fields, a fundamental property of neurons in the visual system, using fMRI and population receptive field (pRF) mapping in 20 human females with monosomic Turner syndrome (TS) (mean age, 10.3 ± 2.0) versus 22 age- and sex-matched controls (mean age, 10.4 ± 1.9). TS, caused by X-chromosome haploinsufficiency in females is associated with well-recognized effects on visual-spatial processing, parieto-occipital cortical anatomy, and parietal lobe function. However, it is unknown if these effects are related to altered brain structure and function in early visual areas (V1-V3) versus downstream parietal cortical regions. Results show that girls with TS have: (i) smaller volume of V1-V3, (ii) lower average pRF eccentricity in early visual areas, and (iii) sparser pRF coverage in the periphery of the visual field. Further, we examined whether the lower volume of early visual areas, defined using retinotopic mapping, in TS is due to smaller surface area or thinner cortex. Results show that girls with TS had a general reduction in surface area relative to controls in bilateral V1 and V2. Our data suggest the possibility that the smaller cortical surface area of early visual areas in girls with TS may be associated with a lower number of neurons which, in turn, leads to lesser coverage of the peripheral visual field compared to controls. These results indicate that X-chromosome haploinsufficiency associated with TS affects the functional neuroanatomy of early visual areas and suggest that investigating pRFs in TS may shed insights into their atypical visual-spatial processing.SIGNIFICANCE STATEMENTTurner syndrome is caused by the absence of one of the two X-chromosome in females. Using functional neuroimaging and population receptive field mapping, we find that chromosome dosage variation (X-monosomy) associated with Turner syndrome affects the functional neuroanatomy of the visual cortex. Specifically, girls with Turner syndrome have smaller early visual areas that provide lesser coverage of the peripheral visual field compared to healthy controls. Our observations provide compelling evidence that the X-chromosome affects not only parietal cortex, as described in previous studies, but also affects early visual areas. These findings suggest a paradigm change in understanding the effect of X-monosomy on the development of visual-spatial abilities in humans.

  View details for DOI 10.1523/JNEUROSCI.2745-18.2019

  View details for PubMedID 31434689

• Neural adaptation to faces reveals racial outgroup homogeneity effects in early perception. Proceedings of the National Academy of Sciences of the United States of America Hughes, B. L., Camp, N. P., Gomez, J., Natu, V. S., Grill-Spector, K., Eberhardt, J. L. 2019

  Abstract

  A hallmark of intergroup biases is the tendency to individuate members of one's own group but process members of other groups categorically. While the consequences of these biases for stereotyping and discrimination are well-documented, their early perceptual underpinnings remain less understood. Here, we investigated the neural mechanisms of this effect by testing whether high-level visual cortex is differentially tuned in its sensitivity to variation in own-race versus other-race faces. Using a functional MRI adaptation paradigm, we measured White participants' habituation to blocks of White and Black faces that parametrically varied in their groupwise similarity. Participants showed a greater tendency to individuate own-race faces in perception, showing both greater release from adaptation to unique identities and increased sensitivity in the adaptation response to physical difference among faces. These group differences emerge in the tuning of early face-selective cortex and mirror behavioral differences in the memory and perception of own- versus other-race faces. Our results suggest that biases for other-race faces emerge at some of the earliest stages of sensory perception.

  View details for DOI 10.1073/pnas.1822084116

  View details for PubMedID 31262811

• Extensive childhood experience with Pokemon suggests eccentricity drives organization of visual cortex NATURE HUMAN BEHAVIOUR Gomez, J., Barnett, M., Grill-Spector, K. 2019; 3 (6): 611–24

  View details for DOI 10.1038/s41562-019-0592-8

  View details for Web of Science ID 000471237800018

• Development of population receptive fields in the lateral visual stream improves spatial coding amid stable structural-functional coupling NEUROIMAGE Gomez, J., Drain, A., Jeska, B., Natu, V. S., Barnett, M., Grill-Spector, K. 2019; 188: 59-69

  View details for DOI 10.1016/j.neuroimage.2018.11.056

  View details for Web of Science ID 000460064700005

• Differential sustained and transient temporal processing across visual streams. PLoS computational biology Stigliani, A. n., Jeska, B. n., Grill-Spector, K. n. 2019; 15 (5): e1007011

  Abstract

  How do high-level visual regions process the temporal aspects of our visual experience? While the temporal sensitivity of early visual cortex has been studied with fMRI in humans, temporal processing in high-level visual cortex is largely unknown. By modeling neural responses with millisecond precision in separate sustained and transient channels, and introducing a flexible encoding framework that captures differences in neural temporal integration time windows and response nonlinearities, we predict fMRI responses across visual cortex for stimuli ranging from 33 ms to 20 s. Using this innovative approach, we discovered that lateral category-selective regions respond to visual transients associated with stimulus onsets and offsets but not sustained visual information. Thus, lateral category-selective regions compute moment-to-moment visual transitions, but not stable features of the visual input. In contrast, ventral category-selective regions process both sustained and transient components of the visual input. Our model revealed that sustained channel responses to prolonged stimuli exhibit adaptation, whereas transient channel responses to stimulus offsets are surprisingly larger than for stimulus onsets. This large offset transient response may reflect a memory trace of the stimulus when it is no longer visible, whereas the onset transient response may reflect rapid processing of new items. Together, these findings reveal previously unconsidered, fundamental temporal mechanisms that distinguish visual streams in the human brain. Importantly, our results underscore the promise of modeling brain responses with millisecond precision to understand the underlying neural computations.

  View details for DOI 10.1371/journal.pcbi.1007011

  View details for PubMedID 31145723

• Separate lanes for adding and reading in the white matter highways of the human brain. Nature communications Grotheer, M. n., Zhen, Z. n., Lerma-Usabiaga, G. n., Grill-Spector, K. n. 2019; 10 (1): 3675

  Abstract

  Math and reading involve distributed brain networks and have both shared (e.g. encoding of visual stimuli) and dissociated (e.g. quantity processing) cognitive components. Yet, to date, the shared vs. dissociated gray and white matter substrates of the math and reading networks are unknown. Here, we define these networks and evaluate the structural properties of their fascicles using functional MRI, diffusion MRI, and quantitative MRI. Our results reveal that there are distinct gray matter regions which are preferentially engaged in either math (adding) or reading, and that the superior longitudinal and arcuate fascicles are shared across the math and reading networks. Strikingly, within these fascicles, reading- and math-related tracts are segregated into parallel sub-bundles and show structural differences related to myelination. These findings open a new avenue of research that examines the contribution of sub-bundles within fascicles to specific behaviors.

  View details for DOI 10.1038/s41467-019-11424-1

  View details for PubMedID 31417075

• Apparent thinning of human visual cortex during childhood is associated with myelination. Proceedings of the National Academy of Sciences of the United States of America Natu, V. S., Gomez, J. n., Barnett, M. n., Jeska, B. n., Kirilina, E. n., Jaeger, C. n., Zhen, Z. n., Cox, S. n., Weiner, K. S., Weiskopf, N. n., Grill-Spector, K. n. 2019

  Abstract

  Human cortex appears to thin during childhood development. However, the underlying microstructural mechanisms are unknown. Using functional magnetic resonance imaging (fMRI), quantitative MRI (qMRI), and diffusion MRI (dMRI) in children and adults, we tested what quantitative changes occur to gray and white matter in ventral temporal cortex (VTC) from childhood to adulthood, and how these changes relate to cortical thinning. T1 relaxation time from qMRI and mean diffusivity (MD) from dMRI provide independent and complementary measurements of microstructural properties of gray and white matter tissue. In face- and character-selective regions in lateral VTC, T1 and MD decreased from age 5 to adulthood in mid and deep cortex, as well as in their adjacent white matter. T1 reduction also occurred longitudinally in children's brain regions. T1 and MD decreases 1) were consistent with tissue growth related to myelination, which we verified with adult histological myelin stains, and 2) were correlated with apparent cortical thinning. In contrast, in place-selective cortex in medial VTC, we found no development of T1 or MD after age 5, and thickness was related to cortical morphology. These findings suggest that lateral VTC likely becomes more myelinated from childhood to adulthood, affecting the contrast of MR images and, in turn, the apparent gray-white boundary. These findings are important because they suggest that VTC does not thin during childhood but instead gets more myelinated. Our data have broad ramifications for understanding both typical and atypical brain development using advanced in vivo quantitative measurements and clinical conditions implicating myelin.

  View details for DOI 10.1073/pnas.1904931116

  View details for PubMedID 31548375

• Development of population receptive fields in the lateral visual stream improves spatial coding amid stable structural-functional coupling. NeuroImage Gomez, J., Drain, A., Jeska, B., Natu, V., Barnett, M., Grill-Spector, K. 2018

  Abstract

  Human visual cortex encompasses more than a dozen visual field maps across three major processing streams. One of these streams is the lateral visual stream, which extends from V1 to lateral-occipital (LO) and temporal-occipital (TO) visual field maps and plays a prominent role in shape as well as motion perception. However, it is unknown if and how population receptive fields (pRFs) in the lateral visual stream develop from childhood to adulthood, and what impact this development may have on spatial coding. Here, we used functional magnetic resonance imaging and pRF modeling in school-age children and adults to investigate the development of the lateral visual stream. Our data reveal four main findings: 1) The topographic organization of eccentricity and polar angle maps of the lateral stream is stable after age five. 2) In both age groups there is a reliable relationship between eccentricity map transitions and cortical folding: the middle occipital gyrus predicts the transition between the peripheral representation of LO and TO maps. 3) pRFs in LO and TO maps undergo differential development from childhood to adulthood, resulting in increasing coverage of the central visual field in LO and of the peripheral visual field in TO. 4) Model-based decoding shows that the consequence of pRF and visual field coverage development is improved spatial decoding from LO and TO distributed responses in adults vs. children. Together, these results explicate both the development and topography of the lateral visual stream. Our data show that the general structural-functional organization is laid out early in development, but fine-scale properties, such as pRF distribution across the visual field and consequently, spatial precision, become fine-tuned across childhood development. These findings advance understanding of the development of the human visual system from childhood to adulthood and provide an essential foundation for understanding developmental deficits.

  View details for PubMedID 30508682

• The functional neuroanatomy of face perception: from brain measurements to deep neural networks Grill-Spector, K., Weiner, K. S., Gomez, J., Stigliani, A., Natu, V. S. ROYAL SOC. 2018

  View details for DOI 10.1098/rsfs.2018.0013

  View details for Web of Science ID 000435410900007

• The functional neuroanatomy of face perception: from brain measurements to deep neural networks. Interface focus Grill-Spector, K., Weiner, K. S., Gomez, J., Stigliani, A., Natu, V. S. 2018; 8 (4): 20180013

  Abstract

  A central goal in neuroscience is to understand how processing within the ventral visual stream enables rapid and robust perception and recognition. Recent neuroscientific discoveries have significantly advanced understanding of the function, structure and computations along the ventral visual stream that serve as the infrastructure supporting this behaviour. In parallel, significant advances in computational models, such as hierarchical deep neural networks (DNNs), have brought machine performance to a level that is commensurate with human performance. Here, we propose a new framework using the ventral face network as a model system to illustrate how increasing the neural accuracy of present DNNs may allow researchers to test the computational benefits of the functional architecture of the human brain. Thus, the review (i) considers specific neural implementational features of the ventral face network, (ii) describes similarities and differences between the functional architecture of the brain and DNNs, and (iii) provides a hypothesis for the computational value of implementational features within the brain that may improve DNN performance. Importantly, this new framework promotes the incorporation of neuroscientific findings into DNNs in order to test the computational benefits of fundamental organizational features of the visual system.

  View details for DOI 10.1098/rsfs.2018.0013

  View details for PubMedID 29951193

  View details for PubMedCentralID PMC6015811

• A preference for mathematical processing outweighs the selectivity for Arabic numbers in the inferior temporal gyrus. NeuroImage Grotheer, M., Jeska, B., Grill-Spector, K. 2018; 175: 188–200

  Abstract

  A region in the posterior inferior temporal gyrus (ITG), referred to as the number form area (NFA, here ITG-numbers) has been implicated in the visual processing of Arabic numbers. However, it is unknown if this region is specifically involved in the visual encoding of Arabic numbers per se or in mathematical processing more broadly. Using functional magnetic resonance imaging (fMRI) during experiments that systematically vary tasks and stimuli, we find that mathematical processing, not preference to Arabic numbers, consistently drives both mean and distributed responses in the posterior ITG. While we replicated findings of higher responses in ITG-numbers to numbers than other visual stimuli during a 1-back task, this preference to numbers was abolished when participants engaged in mathematical processing. In contrast, an ITG region (ITG-math) that showed higher responses during an adding task vs. other tasks maintained this preference for mathematical processing across a wide range of stimuli including numbers, number/letter morphs, hands, and dice. Analysis of distributed responses across an anatomically-defined posterior ITG expanse further revealed that mathematical task but not Arabic number form can be successfully and consistently decoded from these distributed responses. Together, our findings suggest that the function of neuronal regions in the posterior ITG goes beyond the specific visual processing of Arabic numbers. We hypothesize that they ascribe numerical content to the visual input, irrespective of the format of the stimulus.

  View details for PubMedID 29604456

• A preference for mathematical processing outweighs the selectivity for Arabic numbers in the inferior temporal gyrus NEUROIMAGE Grotheer, M., Jeska, B., Grill-Spector, K. 2018; 175: 188-200

  View details for DOI 10.1016/j.neuroimage.2018.03.064

  View details for Web of Science ID 000432949000017

• On object selectivity and the anatomy of the human fusiform gyrus NEUROIMAGE Weiner, K. S., Natu, V. S., Grill-Spector, K. 2018; 173: 604–9

  Abstract

  pFs is a functionally-defined region in the human brain that is involved in recognizing objects. A recent trend refers to pFs as the posterior fusiform sulcus, which is a neuroanatomical structure that does not exist. Here, we correct this mistake. To achieve this goal, we first recount the original definitions of pFs and then review the identification of sulci within and surrounding the fusiform gyrus (FG) including the mid-fusiform sulcus (MFS), which is a tertiary sulcus within the FG. We highlight that tertiary sulci, such as the MFS, are often absent from brain atlases, which complicates the accurate localization of functional regions, as well as the understanding of structural-functional relationships in ventral temporal cortex (VTC). When considering the location of object-selective pFs from previously published data relative to the sulci surrounding the FG, as well as the MFS, we illustrate that (1) pFs spans several macroanatomical structures, which is consistent with the original definitions of pFs (Grill-Spector et al., 1999, 2000), and (2) the topological relationship between pFs and MFS has both stable and variable features. To prevent future confusion regarding the anatomical location of functional regions within VTC, as well as to complement tools that automatically identify sulci surrounding the FG, we provide a method to automatically identify the MFS in individual brains using FreeSurfer. Finally, we highlight the benefits of using cortical surface reconstructions in large datasets to identify and quantify tertiary sulci compared to classic dissection methods because the latter often fail to differentiate tertiary sulci from shallow surface indentations produced by veins and arteries. Altogether, we propose that the inclusion of definitions and labels for tertiary sulci in neuroanatomical atlases and neuroimaging software packages will enhance understanding of functional-structural relationships throughout the human brain.

  View details for PubMedID 29471101

• Development differentially sculpts receptive fields across early and high-level human visual cortex. Nature communications Gomez, J., Natu, V., Jeska, B., Barnett, M., Grill-Spector, K. 2018; 9 (1): 788

  Abstract

  Receptive fields (RFs) processing information in restricted parts of the visual field are a key property of visual system neurons. However, how RFs develop in humans is unknown. Using fMRI and population receptive field (pRF) modeling in children and adults, we determine where and how pRFs develop across the ventral visual stream. Here we report that pRF properties in visual field maps, from the first visual area, V1, through the first ventro-occipital area, VO1, are adult-like by age 5. However, pRF properties in face-selective and character-selective regions develop into adulthood, increasing the foveal coverage bias for faces in the right hemisphere and words in the left hemisphere. Eye-tracking indicates that pRF changes are related to changing fixation patterns on words and faces across development. These findings suggest a link between face and word viewing behavior and the differential development of pRFs across visual cortex, potentially due to competition on foveal coverage.

  View details for DOI 10.1038/s41467-018-03166-3

  View details for PubMedID 29476135

  View details for PubMedCentralID PMC5824941

• Development differentially sculpts receptive fields across early and high-level human visual cortex Nature Communications Gomez, J., Natu, V., Jeska, B., Barnett, M., Grill-Spector, K. 2018; 9: 788

  Abstract

  Receptive fields (RFs) processing information in restricted parts of the visual field are a key property of visual system neurons. However, how RFs develop in humans is unknown. Using fMRI and population receptive field (pRF) modeling in children and adults, we determine where and how pRFs develop across the ventral visual stream. Here we report that pRF properties in visual field maps, from the first visual area, V1, through the first ventro-occipital area, VO1, are adult-like by age 5. However, pRF properties in face-selective and character-selective regions develop into adulthood, increasing the foveal coverage bias for faces in the right hemisphere and words in the left hemisphere. Eye-tracking indicates that pRF changes are related to changing fixation patterns on words and faces across development. These findings suggest a link between face and word viewing behavior and the differential development of pRFs across visual cortex, potentially due to competition on foveal coverage.

  View details for DOI 10.1038/s41467-018-03166-3

  View details for PubMedCentralID PMC5824941

• Learning to Read Increases the Informativeness of Distributed Ventral Temporal Responses. Cerebral cortex (New York, N.Y. : 1991) Nordt, M. n., Gomez, J. n., Natu, V. n., Jeska, B. n., Barnett, M. n., Grill-Spector, K. n. 2018

  Abstract

  Becoming a proficient reader requires substantial learning over many years. However, it is unknown how learning to read affects development of distributed visual representations across human ventral temporal cortex (VTC). Using fMRI and a data-driven, computational approach, we quantified the development of distributed VTC responses to characters (pseudowords and numbers) versus other domains in children, preteens, and adults. Results reveal anatomical- and hemisphere-specific development. With development, distributed responses to words and characters became more distinctive and informative in lateral but not medial VTC, and in the left but not right hemisphere. While the development of voxels with both positive and negative preference to words affected distributed information, only development of voxels with positive preference to words (i.e., word-selective) was correlated with reading ability. These data show that developmental increases in informativeness of distributed left lateral VTC responses are related to proficient reading and have important implications for both developmental theories and for elucidating neural mechanisms of reading disabilities.

  View details for PubMedID 30169753

• Data on a cytoarchitectonic brain atlas: effects of brain template and a comparison to a multimodal atlas. Data in brief Rosenke, M., Weiner, K. S., Barnett, M. A., Zilles, K., Amunts, K., Goebel, R., Grill-Spector, K. 2017; 12: 327-332

  Abstract

  The data presented here are related to the research article: "A cross-validated cytoarchitectonic atlas of the human ventral visual stream" in which we developed a cytoarchitectonic atlas of ventral visual cortex. Here, we provide two additional quantifications of this cytoarchitectonic atlas: First, we quantify the effect of brain template on cross-validation performance. The data show a comparison between cortex-based alignment to two templates: the postmortem average brain and the FreeSurfer average brain. Second, we quantify the relationship between this cytoarchitectonic atlas and a recently published multimodal atlas of the human brain (Glasser et al., 2016).

  View details for DOI 10.1016/j.dib.2017.04.007

  View details for PubMedID 28487876

• Defining the most probable location of the parahippocampal place area using cortex-based alignment and cross-validation. NeuroImage Weiner, K. S., Barnett, M. A., Witthoft, N., Golarai, G., Stigliani, A., Kay, K. N., Gomez, J., Natu, V. S., Amunts, K., Zilles, K., Grill-Spector, K. 2017

  Abstract

  The parahippocampal place area (PPA) is a widely studied high-level visual region in the human brain involved in place and scene processing. The goal of the present study was to identify the most probable location of place-selective voxels in medial ventral temporal cortex. To achieve this goal, we first used cortex-based alignment (CBA) to create a probabilistic place-selective region of interest (ROI) from one group of 12 participants. We then tested how well this ROI could predict place selectivity in each hemisphere within a new group of 12 participants. Our results reveal that a probabilistic ROI (pROI) generated from one group of 12 participants accurately predicts the location and functional selectivity in individual brains from a new group of 12 participants, despite between subject variability in the exact location of place-selective voxels relative to the folding of parahippocampal cortex. Additionally, the prediction accuracy of our pROI is significantly higher than that achieved by volume-based Talairach alignment. Comparing the location of the pROI of the PPA relative to published data from over 500 participants, including data from the Human Connectome Project, shows a striking convergence of the predicted location of the PPA and the cortical location of voxels exhibiting the highest place selectivity across studies using various methods and stimuli. Specifically, the most predictive anatomical location of voxels exhibiting the highest place selectivity in medial ventral temporal cortex is the junction of the collateral and anterior lingual sulci. Methodologically, we make this pROI freely available (vpnl.stanford.edu/PlaceSelectivity), which provides a means to accurately identify a functional region from anatomical MRI data when fMRI data are not available (for example, in patient populations). Theoretically, we consider different anatomical and functional factors that may contribute to the consistent anatomical location of place selectivity relative to the folding of high-level visual cortex.

  View details for DOI 10.1016/j.neuroimage.2017.04.040

  View details for PubMedID 28435097

• Task alters category representations in prefrontal but not high-level visual cortex. NeuroImage Bugatus, L., Weiner, K. S., Grill-Spector, K. 2017

  Abstract

  A central question in neuroscience is how cognitive tasks affect category representations across the human brain. Regions in lateral occipito-temporal cortex (LOTC), ventral temporal cortex (VTC), and ventro-lateral prefrontal cortex (VLFPC) constitute the extended "what" pathway, which is considered instrumental for visual category processing. However, it is unknown (1) whether distributed responses across LOTC, VTC, and VLPFC explicitly represent category, task, or some combination of both, and (2) in what way representations across these subdivisions of the extended 'what' pathway may differ. To fill these gaps in knowledge, we scanned 12 participants using fMRI to test the effect of category and task on distributed responses across LOTC, VTC, and VLPFC. Results reveal that task and category modulate responses in both high-level visual regions, as well as prefrontal cortex. However, we found fundamentally different types of representations across the brain. Distributed responses in high-level visual regions are more strongly driven by category than task, and exhibit task-independent category representations. In contrast, distributed responses in prefrontal cortex are more strongly driven by task than category, and contain task-dependent category representations. Together, these findings of differential representations across the brain support a new idea that LOTC and VTC maintain stable category representations allowing efficient processing of visual information, while prefrontal cortex contains flexible representations in which category information may emerge only when relevant to the task.

  View details for DOI 10.1016/j.neuroimage.2017.03.062

  View details for PubMedID 28389381

• A cross-validated cytoarchitectonic atlas of the human ventral visual stream. NeuroImage Rosenke, M., Weiner, K. S., Barnett, M. A., Zilles, K., Amunts, K., Goebel, R., Grill-Spector, K. 2017

  Abstract

  The human ventral visual stream consists of several areas that are considered processing stages essential for perception and recognition. A fundamental microanatomical feature differentiating areas is cytoarchitecture, which refers to the distribution, size, and density of cells across cortical layers. Because cytoarchitectonic structure is measured in 20-micron-thick histological slices of postmortem tissue, it is difficult to assess (a) how anatomically consistent these areas are across brains and (b) how they relate to brain parcellations obtained with prevalent neuroimaging methods, acquired at the millimeter and centimeter scale. Therefore, the goal of this study was to (a) generate a cross-validated cytoarchitectonic atlas of the human ventral visual stream on a whole brain template that is commonly used in neuroimaging studies and (b) to compare this atlas to a recently published retinotopic parcellation of visual cortex (Wang et al., 2014). To achieve this goal, we generated an atlas of eight cytoarchitectonic areas: four areas in the occipital lobe (hOc1-hOc4v) and four in the fusiform gyrus (FG1-FG4), then we tested how the different alignment techniques affect the accuracy of the resulting atlas. Results show that both cortex-based alignment (CBA) and nonlinear volumetric alignment (NVA) generate an atlas with better cross-validation performance than affine volumetric alignment (AVA). Additionally, CBA outperformed NVA in 6/8 of the cytoarchitectonic areas. Finally, the comparison of the cytoarchitectonic atlas to a retinotopic atlas shows a clear correspondence between cytoarchitectonic and retinotopic areas in the ventral visual stream. The successful performance of CBA suggests a coupling between cytoarchitectonic areas and macroanatomical landmarks in the human ventral visual stream, and furthermore, that this coupling can be utilized for generating an accurate group atlas. In addition, the coupling between cytoarchitecture and retinotopy highlights the potential use of this atlas in understanding how anatomical features contribute to brain function. We make this cytoarchitectonic atlas freely available in both BrainVoyager and FreeSurfer formats (http://vpnl.stanford.edu/vcAtlas). The availability of this atlas will enable future studies to link cytoarchitectonic organization to other parcellations of the human ventral visual stream with potential to advance the understanding of this pathway in typical and atypical populations.

  View details for DOI 10.1016/j.neuroimage.2017.02.040

  View details for PubMedID 28213120

• Experience Shapes the Development of Neural Substrates of Face Processing in Human Ventral Temporal Cortex CEREBRAL CORTEX Golarai, G., Liberman, A., Grill-Spector, K. 2017; 27 (2): 1229-1244

  Abstract

  In adult humans, the ventral temporal cortex (VTC) represents faces in a reproducible topology. However, it is unknown what role visual experience plays in the development of this topology. Using functional magnetic resonance imaging in children and adults, we found a sequential development, in which the topology of face-selective activations across the VTC was matured by age 7, but the spatial extent and degree of face selectivity continued to develop past age 7 into adulthood. Importantly, own- and other-age faces were differentially represented, both in the distributed multivoxel patterns across the VTC, and also in the magnitude of responses of face-selective regions. These results provide strong evidence that experience shapes cortical representations of faces during development from childhood to adulthood. Our findings have important implications for the role of experience and age in shaping the neural substrates of face processing in the human VTC.

  View details for DOI 10.1093/cercor/bhv314

  View details for Web of Science ID 000397257600027

• Microstructural proliferation in human cortex is coupled with the development of face processing SCIENCE Gomez, J., Barnett, M. A., Natu, V., Mezer, A., Palomero-Gallagher, N., Weiner, K. S., Amunts, K., Zilles, K., Grill-Spector, K. 2017; 355 (6320): 68-?

  Abstract

  How does cortical tissue change as brain function and behavior improve from childhood to adulthood? By combining quantitative and functional magnetic resonance imaging in children and adults, we find differential development of high-level visual areas that are involved in face and place recognition. Development of face-selective regions, but not place-selective regions, is dominated by microstructural proliferation. This tissue development is correlated with specific increases in functional selectivity to faces, as well as improvements in face recognition, and ultimately leads to differentiated tissue properties between face- and place-selective regions in adulthood, which we validate with postmortem cytoarchitectonic measurements. These data suggest a new model by which emergent brain function and behavior result from cortical tissue proliferation rather than from pruning exclusively.

  View details for DOI 10.1126/science.aag0311

  View details for Web of Science ID 000391739900044

  View details for PubMedID 28059764

  View details for PubMedCentralID PMC5373008

• The Cytoarchitecture of Domain-specific Regions in Human High-level Visual Cortex CEREBRAL CORTEX Weiner, K. S., Barnett, M. A., Lorenz, S., Caspers, J., Stigliani, A., Amunts, K., Zilles, K., Fischl, B., Grill-Spector, K. 2017; 27 (1): 146-161

  Abstract

  A fundamental hypothesis in neuroscience proposes that underlying cellular architecture (cytoarchitecture) contributes to the functionality of a brain area. However, this hypothesis has not been tested in human ventral temporal cortex (VTC) that contains domain-specific regions causally involved in perception. To fill this gap in knowledge, we used cortex-based alignment to register functional regions from living participants to cytoarchitectonic areas in ex vivo brains. This novel approach reveals 3 findings. First, there is a consistent relationship between domain-specific regions and cytoarchitectonic areas: each functional region is largely restricted to 1 cytoarchitectonic area. Second, extracting cytoarchitectonic profiles from face- and place-selective regions after back-projecting each region to 20-μm thick histological sections indicates that cytoarchitectonic properties distinguish these regions from each other. Third, some cytoarchitectonic areas contain more than 1 domain-specific region. For example, face-, body-, and character-selective regions are located within the same cytoarchitectonic area. We summarize these findings with a parsimonious hypothesis incorporating how cellular properties may contribute to functional specialization in human VTC. Specifically, we link computational principles to correlated axes of functional and cytoarchitectonic segregation in human VTC, in which parallel processing across domains occurs along a lateral-medial axis while transformations of information within domain occur along an anterior-posterior axis.

  View details for DOI 10.1093/cercor/bhw361

  View details for Web of Science ID 000397064800013

• The Functional Neuroanatomy of Human Face Perception. Annual review of vision science Grill-Spector, K. n., Weiner, K. S., Kay, K. n., Gomez, J. n. 2017; 3: 167–96

  Abstract

  Face perception is critical for normal social functioning and is mediated by a network of regions in the ventral visual stream. In this review, we describe recent neuroimaging findings regarding the macro- and microscopic anatomical features of the ventral face network, the characteristics of white matter connections, and basic computations performed by population receptive fields within face-selective regions composing this network. We emphasize the importance of the neural tissue properties and white matter connections of each region, as these anatomical properties may be tightly linked to the functional characteristics of the ventral face network. We end by considering how empirical investigations of the neural architecture of the face network may inform the development of computational models and shed light on how computations in the face network enable efficient face perception.

  View details for PubMedID 28715955

• Encoding model of temporal processing in human visual cortex. Proceedings of the National Academy of Sciences of the United States of America Stigliani, A. n., Jeska, B. n., Grill-Spector, K. n. 2017; 114 (51): E11047–E11056

  Abstract

  How is temporal information processed in human visual cortex? Visual input is relayed to V1 through segregated transient and sustained channels in the retina and lateral geniculate nucleus (LGN). However, there is intense debate as to how sustained and transient temporal channels contribute to visual processing beyond V1. The prevailing view associates transient processing predominately with motion-sensitive regions and sustained processing with ventral stream regions, while the opposing view suggests that both temporal channels contribute to neural processing beyond V1. Using fMRI, we measured cortical responses to time-varying stimuli and then implemented a two temporal channel-encoding model to evaluate the contributions of each channel. Different from the general linear model of fMRI that predicts responses directly from the stimulus, the encoding approach first models neural responses to the stimulus from which fMRI responses are derived. This encoding approach not only predicts cortical responses to time-varying stimuli from milliseconds to seconds but also, reveals differential contributions of temporal channels across visual cortex. Consistent with the prevailing view, motion-sensitive regions and adjacent lateral occipitotemporal regions are dominated by transient responses. However, ventral occipitotemporal regions are driven by both sustained and transient channels, with transient responses exceeding the sustained. These findings propose a rethinking of temporal processing in the ventral stream and suggest that transient processing may contribute to rapid extraction of the content of the visual input. Importantly, our encoding approach has vast implications, because it can be applied with fMRI to decipher neural computations in millisecond resolution in any part of the brain.

  View details for PubMedID 29208714

  View details for PubMedCentralID PMC5754759

• Two New Cytoarchitectonic Areas on the Human Mid-Fusiform Gyrus CEREBRAL CORTEX Lorenz, S., Weiner, K. S., Caspers, J., Mohlberg, H., Schleicher, A., Bludau, S., Eickhoff, S., Grill-Spector, K., Zilles, K., Amunts, K. 2017; 27 (1): 373-385

  Abstract

  Areas of the fusiform gyrus (FG) within human ventral temporal cortex (VTC) process high-level visual information associated with faces, limbs, words, and places. Since classical cytoarchitectonic maps do not adequately reflect the functional and structural heterogeneity of the VTC, we studied the cytoarchitectonic segregation in a region, which is rostral to the recently identified cytoarchitectonic areas FG1 and FG2. Using an observer-independent and statistically testable parcellation method, we identify 2 new areas, FG3 and FG4, in 10 human postmortem brains on the mid-FG. The mid-fusiform sulcus reliably identifies the cytoarchitectonic transition between FG3 and FG4. We registered these cytoarchitectonic areas to the common reference space of the single-subject Montreal Neurological Institute (MNI) template and generated probability maps, which reflect the intersubject variability of both areas. Future studies can relate in vivo neuroimaging data with these microscopically defined cortical areas to functional parcellations. We discuss these results in the context of both large-scale functional maps and fine-scale functional clusters that have been identified within the human VTC. We propose that our observer-independent cytoarchitectonic parcellation of the FG better explains the functional heterogeneity of the FG compared with the homogeneity of classic cytoarchitectonic maps.

  View details for DOI 10.1093/cercor/bhv225

  View details for Web of Science ID 000397064800030

• The Cytoarchitecture of Domain-specific Regions in Human High-level Visual Cortex. Cerebral cortex Weiner, K. S., Barnett, M. A., Lorenz, S., Caspers, J., Stigliani, A., Amunts, K., Zilles, K., Fischl, B., Grill-Spector, K. 2016: -?

  Abstract

  A fundamental hypothesis in neuroscience proposes that underlying cellular architecture (cytoarchitecture) contributes to the functionality of a brain area. However, this hypothesis has not been tested in human ventral temporal cortex (VTC) that contains domain-specific regions causally involved in perception. To fill this gap in knowledge, we used cortex-based alignment to register functional regions from living participants to cytoarchitectonic areas in ex vivo brains. This novel approach reveals 3 findings. First, there is a consistent relationship between domain-specific regions and cytoarchitectonic areas: each functional region is largely restricted to 1 cytoarchitectonic area. Second, extracting cytoarchitectonic profiles from face- and place-selective regions after back-projecting each region to 20-μm thick histological sections indicates that cytoarchitectonic properties distinguish these regions from each other. Third, some cytoarchitectonic areas contain more than 1 domain-specific region. For example, face-, body-, and character-selective regions are located within the same cytoarchitectonic area. We summarize these findings with a parsimonious hypothesis incorporating how cellular properties may contribute to functional specialization in human VTC. Specifically, we link computational principles to correlated axes of functional and cytoarchitectonic segregation in human VTC, in which parallel processing across domains occurs along a lateral-medial axis while transformations of information within domain occur along an anterior-posterior axis.

  View details for PubMedID 27909003

• Development of Neural Sensitivity to Face Identity Correlates with Perceptual Discriminability. journal of neuroscience Natu, V. S., Barnett, M. A., Hartley, J., Gomez, J., Stigliani, A., Grill-Spector, K. 2016; 36 (42): 10893-10907

  Abstract

  Face perception is subserved by a series of face-selective regions in the human ventral stream, which undergo prolonged development from childhood to adulthood. However, it is unknown how neural development of these regions relates to the development of face-perception abilities. Here, we used functional magnetic resonance imaging (fMRI) to measure brain responses of ventral occipitotemporal regions in children (ages, 5-12 years) and adults (ages, 19-34 years) when they viewed faces that parametrically varied in dissimilarity. Since similar faces generate lower responses than dissimilar faces due to fMRI adaptation, this design objectively evaluates neural sensitivity to face identity across development. Additionally, a subset of subjects participated in a behavioral experiment to assess perceptual discriminability of face identity. Our data reveal three main findings: (1) neural sensitivity to face identity increases with age in face-selective but not object-selective regions; (2) the amplitude of responses to faces increases with age in both face-selective and object-selective regions; and (3) perceptual discriminability of face identity is correlated with the neural sensitivity to face identity of face-selective regions. In contrast, perceptual discriminability is not correlated with the amplitude of response in face-selective regions or of responses of object-selective regions. These data suggest that developmental increases in neural sensitivity to face identity in face-selective regions improve perceptual discriminability of faces. Our findings significantly advance the understanding of the neural mechanisms of development of face perception and open new avenues for using fMRI adaptation to study the neural development of high-level visual and cognitive functions more broadly.Face perception, which is critical for daily social interactions, develops from childhood to adulthood. However, it is unknown what developmental changes in the brain lead to improved performance. Using fMRI in children and adults, we find that from childhood to adulthood, neural sensitivity to changes in face identity increases in face-selective regions. Critically, subjects' perceptual discriminability among faces is linked to neural sensitivity: participants with higher neural sensitivity in face-selective regions demonstrate higher perceptual discriminability. Thus, our results suggest that developmental increases in face-selective regions' sensitivity to face identity improve perceptual discrimination of faces. These findings significantly advance understanding of the neural mechanisms underlying the development of face perception and have important implications for assessing both typical and atypical development.

  View details for PubMedID 27798143

• The Face-Processing Network Is Resilient to Focal Resection of Human Visual Cortex. journal of neuroscience Weiner, K. S., Jonas, J., Gomez, J., Maillard, L., Brissart, H., Hossu, G., Jacques, C., Loftus, D., Colnat-Coulbois, S., Stigliani, A., Barnett, M. A., Grill-Spector, K., Rossion, B. 2016; 36 (32): 8425-8440

  Abstract

  Human face perception requires a network of brain regions distributed throughout the occipital and temporal lobes with a right hemisphere advantage. Present theories consider this network as either a processing hierarchy beginning with the inferior occipital gyrus (occipital face area; IOG-faces/OFA) or a multiple-route network with nonhierarchical components. The former predicts that removing IOG-faces/OFA will detrimentally affect downstream stages, whereas the latter does not. We tested this prediction in a human patient (Patient S.P.) requiring removal of the right inferior occipital cortex, including IOG-faces/OFA. We acquired multiple fMRI measurements in Patient S.P. before and after a preplanned surgery and multiple measurements in typical controls, enabling both within-subject/across-session comparisons (Patient S.P. before resection vs Patient S.P. after resection) and between-subject/across-session comparisons (Patient S.P. vs controls). We found that the spatial topology and selectivity of downstream ipsilateral face-selective regions were stable 1 and 8 month(s) after surgery. Additionally, the reliability of distributed patterns of face selectivity in Patient S.P. before versus after resection was not different from across-session reliability in controls. Nevertheless, postoperatively, representations of visual space were typical in dorsal face-selective regions but atypical in ventral face-selective regions and V1 of the resected hemisphere. Diffusion weighted imaging in Patient S.P. and controls identifies white matter tracts connecting retinotopic areas to downstream face-selective regions, which may contribute to the stable and plastic features of the face network in Patient S.P. after surgery. Together, our results support a multiple-route network of face processing with nonhierarchical components and shed light on stable and plastic features of high-level visual cortex following focal brain damage.Brain networks consist of interconnected functional regions commonly organized in processing hierarchies. Prevailing theories predict that damage to the input of the hierarchy will detrimentally affect later stages. We tested this prediction with multiple brain measurements in a rare human patient requiring surgical removal of the putative input to a network processing faces. Surprisingly, the spatial topology and selectivity of downstream face-selective regions are stable after surgery. Nevertheless, representations of visual space were typical in dorsal face-selective regions but atypical in ventral face-selective regions and V1. White matter connections from outside the face network may support these stable and plastic features. As processing hierarchies are ubiquitous in biological and nonbiological systems, our results have pervasive implications for understanding the construction of resilient networks.

  View details for DOI 10.1523/JNEUROSCI.4509-15.2016

  View details for PubMedID 27511014

  View details for PubMedCentralID PMC4978802

• Learning the 3-D structure of objects from 2-D views depends on shape, not format JOURNAL OF VISION Tian, M., Yamins, D., Grill-Spector, K. 2016; 16 (7)

  Abstract

  Humans can learn to recognize new objects just from observing example views. However, it is unknown what structural information enables this learning. To address this question, we manipulated the amount of structural information given to subjects during unsupervised learning by varying the format of the trained views. We then tested how format affected participants' ability to discriminate similar objects across views that were rotated 90° apart. We found that, after training, participants' performance increased and generalized to new views in the same format. Surprisingly, the improvement was similar across line drawings, shape from shading, and shape from shading + stereo even though the latter two formats provide richer depth information compared to line drawings. In contrast, participants' improvement was significantly lower when training used silhouettes, suggesting that silhouettes do not have enough information to generate a robust 3-D structure. To test whether the learned object representations were format-specific or format-invariant, we examined if learning novel objects from example views transfers across formats. We found that learning objects from example line drawings transferred to shape from shading and vice versa. These results have important implications for theories of object recognition because they suggest that (a) learning the 3-D structure of objects does not require rich structural cues during training as long as shape information of internal and external features is provided and (b) learning generates shape-based object representations independent of the training format.

  View details for DOI 10.1167/16.7.7

  View details for Web of Science ID 000377938400007

  View details for PubMedID 27153196

  View details for PubMedCentralID PMC4898268

• Corresponding ECoG and fMRI category-selective signals in human ventral temporal cortex. Neuropsychologia Jacques, C., Witthoft, N., Weiner, K. S., Foster, B. L., Rangarajan, V., Hermes, D., Miller, K. J., Parvizi, J., Grill-Spector, K. 2016; 83: 14-28

  Abstract

  Functional magnetic resonance imaging (fMRI) and electrocorticography (ECoG) research have been influential in revealing the functional characteristics of category-selective responses in human ventral temporal cortex (VTC). One important, but unanswered, question is how these two types of measurements might be related with respect to the VTC. Here we examined which components of the ECoG signal correspond to the fMRI response, by using a rare opportunity to measure both fMRI and ECoG responses from the same individuals to images of exemplars of various categories including faces, limbs, cars and houses. Our data reveal three key findings. First, we discovered that the coupling between fMRI and ECoG responses is frequency and time dependent. The strongest and most sustained correlation is observed between fMRI and high frequency broadband (HFB) ECoG responses (30-160hz). In contrast, the correlation between fMRI and ECoG signals in lower frequency bands is temporally transient, where the correlation is initially positive, but then tapers off or becomes negative. Second, we find that the strong and positive correlation between fMRI and ECoG signals in all frequency bands emerges rapidly around 100ms after stimulus onset, together with the onset of the first stimulus-driven neural signals in VTC. Third, we find that the spatial topology and representational structure of category-selectivity in VTC reflected in ECoG HFB responses mirrors the topology and structure observed with fMRI. These findings of a strong and rapid coupling between fMRI and HFB responses validate fMRI measurements of functional selectivity with recordings of direct neural activity and suggest that fMRI category-selective signals in VTC are associated with feed-forward neural processing.

  View details for DOI 10.1016/j.neuropsychologia.2015.07.024

  View details for PubMedID 26212070

• Introduction to the special issue on functional selectivity in perceptual and cognitive systems--a tribute to Shlomo Bentin (1946-2012). Neuropsychologia Deouell, L. Y., Grill-Spector, K. n., Malach, R. n., Murray, M. M., Rossion, B. n. 2016; 83: 1–4

  View details for PubMedID 26826521

  View details for PubMedCentralID PMC4924878

• Experience Shapes the Development of Neural Substrates of Face Processing in Human Ventral Temporal Cortex. Cerebral cortex Golarai, G., Liberman, A., Grill-Spector, K. 2015

  Abstract

  In adult humans, the ventral temporal cortex (VTC) represents faces in a reproducible topology. However, it is unknown what role visual experience plays in the development of this topology. Using functional magnetic resonance imaging in children and adults, we found a sequential development, in which the topology of face-selective activations across the VTC was matured by age 7, but the spatial extent and degree of face selectivity continued to develop past age 7 into adulthood. Importantly, own- and other-age faces were differentially represented, both in the distributed multivoxel patterns across the VTC, and also in the magnitude of responses of face-selective regions. These results provide strong evidence that experience shapes cortical representations of faces during development from childhood to adulthood. Our findings have important implications for the role of experience and age in shaping the neural substrates of face processing in the human VTC.

  View details for PubMedID 26683171

• Two New Cytoarchitectonic Areas on the Human Mid-Fusiform Gyrus. Cerebral cortex Lorenz, S., Weiner, K. S., Caspers, J., Mohlberg, H., Schleicher, A., Bludau, S., Eickhoff, S. B., Grill-Spector, K., Zilles, K., Amunts, K. 2015

  Abstract

  Areas of the fusiform gyrus (FG) within human ventral temporal cortex (VTC) process high-level visual information associated with faces, limbs, words, and places. Since classical cytoarchitectonic maps do not adequately reflect the functional and structural heterogeneity of the VTC, we studied the cytoarchitectonic segregation in a region, which is rostral to the recently identified cytoarchitectonic areas FG1 and FG2. Using an observer-independent and statistically testable parcellation method, we identify 2 new areas, FG3 and FG4, in 10 human postmortem brains on the mid-FG. The mid-fusiform sulcus reliably identifies the cytoarchitectonic transition between FG3 and FG4. We registered these cytoarchitectonic areas to the common reference space of the single-subject Montreal Neurological Institute (MNI) template and generated probability maps, which reflect the intersubject variability of both areas. Future studies can relate in vivo neuroimaging data with these microscopically defined cortical areas to functional parcellations. We discuss these results in the context of both large-scale functional maps and fine-scale functional clusters that have been identified within the human VTC. We propose that our observer-independent cytoarchitectonic parcellation of the FG better explains the functional heterogeneity of the FG compared with the homogeneity of classic cytoarchitectonic maps.

  View details for PubMedID 26464475

• Temporal Processing Capacity in High-Level Visual Cortex Is Domain Specific. journal of neuroscience Stigliani, A., Weiner, K. S., Grill-Spector, K. 2015; 35 (36): 12412-12424

  Abstract

  Prevailing hierarchical models propose that temporal processing capacity-the amount of information that a brain region processes in a unit time-decreases at higher stages in the ventral stream regardless of domain. However, it is unknown if temporal processing capacities are domain general or domain specific in human high-level visual cortex. Using a novel fMRI paradigm, we measured temporal capacities of functional regions in high-level visual cortex. Contrary to hierarchical models, our data reveal domain-specific processing capacities as follows: (1) regions processing information from different domains have differential temporal capacities within each stage of the visual hierarchy and (2) domain-specific regions display the same temporal capacity regardless of their position in the processing hierarchy. In general, character-selective regions have the lowest capacity, face- and place-selective regions have an intermediate capacity, and body-selective regions have the highest capacity. Notably, domain-specific temporal processing capacities are not apparent in V1 and have perceptual implications. Behavioral testing revealed that the encoding capacity of body images is higher than that of characters, faces, and places, and there is a correspondence between peak encoding rates and cortical capacities for characters and bodies. The present evidence supports a model in which the natural statistics of temporal information in the visual world may affect domain-specific temporal processing and encoding capacities. These findings suggest that the functional organization of high-level visual cortex may be constrained by temporal characteristics of stimuli in the natural world, and this temporal capacity is a characteristic of domain-specific networks in high-level visual cortex.Visual stimuli bombard us at different rates every day. For example, words and scenes are typically stationary and vary at slow rates. In contrast, bodies are dynamic and typically change at faster rates. Using a novel fMRI paradigm, we measured temporal processing capacities of functional regions in human high-level visual cortex. Contrary to prevailing theories, we find that different regions have different processing capacities, which have behavioral implications. In general, character-selective regions have the lowest capacity, face- and place-selective regions have an intermediate capacity, and body-selective regions have the highest capacity. These results suggest that temporal processing capacity is a characteristic of domain-specific networks in high-level visual cortex and contributes to the segregation of cortical regions.

  View details for DOI 10.1523/JNEUROSCI.4822-14.2015

  View details for PubMedID 26354910

  View details for PubMedCentralID PMC4563034

• The evolution of face processing networks. Trends in cognitive sciences Weiner, K. S., Grill-Spector, K. 2015; 19 (5): 240-241

  Abstract

  Recent studies in marmosets, macaques, and humans have begun to show commonalities and differences in the evolution of face processing networks. Despite differences in brain size and gyrification across species, myelination and motion may be key anatomical and functional features contributing to the surprising similarity of face networks across species.

  View details for DOI 10.1016/j.tics.2015.03.010

  View details for PubMedID 25840651

  View details for PubMedCentralID PMC4414913

• Attention reduces spatial uncertainty in human ventral temporal cortex. Current biology Kay, K. N., Weiner, K. S., Grill-Spector, K. 2015; 25 (5): 595-600

  Abstract

  Ventral temporal cortex (VTC) is the latest stage of the ventral "what" visual pathway, which is thought to code the identity of a stimulus regardless of its position or size [1, 2]. Surprisingly, recent studies show that position information can be decoded from VTC [3-5]. However, the computational mechanisms by which spatial information is encoded in VTC are unknown. Furthermore, how attention influences spatial representations in human VTC is also unknown because the effect of attention on spatial representations has only been examined in the dorsal "where" visual pathway [6-10]. Here, we fill these significant gaps in knowledge using an approach that combines functional magnetic resonance imaging and sophisticated computational methods. We first develop a population receptive field (pRF) model [11, 12] of spatial responses in human VTC. Consisting of spatial summation followed by a compressive nonlinearity, this model accurately predicts responses of individual voxels to stimuli at any position and size, explains how spatial information is encoded, and reveals a functional hierarchy in VTC. We then manipulate attention and use our model to decipher the effects of attention. We find that attention to the stimulus systematically and selectively modulates responses in VTC, but not early visual areas. Locally, attention increases eccentricity, size, and gain of individual pRFs, thereby increasing position tolerance. However, globally, these effects reduce uncertainty regarding stimulus location and actually increase position sensitivity of distributed responses across VTC. These results demonstrate that attention actively shapes and enhances spatial representations in the ventral visual pathway.

  View details for DOI 10.1016/j.cub.2014.12.050

  View details for PubMedID 25702580

  View details for PubMedCentralID PMC4348205

• Feature saliency and feedback information interactively impact visual category learning FRONTIERS IN PSYCHOLOGY Hammer, R., Sloutsky, V., Grill-Spector, K. 2015; 6

  Abstract

  Visual category learning (VCL) involves detecting which features are most relevant for categorization. VCL relies on attentional learning, which enables effectively redirecting attention to object's features most relevant for categorization, while 'filtering out' irrelevant features. When features relevant for categorization are not salient, VCL relies also on perceptual learning, which enables becoming more sensitive to subtle yet important differences between objects. Little is known about how attentional learning and perceptual learning interact when VCL relies on both processes at the same time. Here we tested this interaction. Participants performed VCL tasks in which they learned to categorize novel stimuli by detecting the feature dimension relevant for categorization. Tasks varied both in feature saliency (low-saliency tasks that required perceptual learning vs. high-saliency tasks), and in feedback information (tasks with mid-information, moderately ambiguous feedback that increased attentional load, vs. tasks with high-information non-ambiguous feedback). We found that mid-information and high-information feedback were similarly effective for VCL in high-saliency tasks. This suggests that an increased attentional load, associated with the processing of moderately ambiguous feedback, has little effect on VCL when features are salient. In low-saliency tasks, VCL relied on slower perceptual learning; but when the feedback was highly informative participants were able to ultimately attain the same performance as during the high-saliency VCL tasks. However, VCL was significantly compromised in the low-saliency mid-information feedback task. We suggest that such low-saliency mid-information learning scenarios are characterized by a 'cognitive loop paradox' where two interdependent learning processes have to take place simultaneously.

  View details for DOI 10.3389/fpsyg.2015.00074

  View details for Web of Science ID 000349595900001

  View details for PubMedID 25745404

  View details for PubMedCentralID PMC4333777

• Functionally defined white matter reveals segregated pathways in human ventral temporal cortex associated with category-specific processing. Neuron Gomez, J., Pestilli, F., Witthoft, N., Golarai, G., Liberman, A., Poltoratski, S., Yoon, J., Grill-Spector, K. 2015; 85 (1): 216-227

  Abstract

  It is unknown if the white-matter properties associated with specific visual networks selectively affect category-specific processing. In a novel protocol we combined measurements of white-matter structure, functional selectivity, and behavior in the same subjects. We find two parallel white-matter pathways along the ventral temporal lobe connecting to either face-selective or place-selective regions. Diffusion properties of portions of these tracts adjacent to face- and place-selective regions of ventral temporal cortex correlate with behavioral performance for face or place processing, respectively. Strikingly, adults with developmental prosopagnosia (face blindness) express an atypical structure-behavior relationship near face-selective cortex, suggesting that white-matter atypicalities in this region may have behavioral consequences. These data suggest that examining the interplay between cortical function, anatomical connectivity, and visual behavior is integral to understanding functional networks and their role in producing visual abilities and deficits.

  View details for DOI 10.1016/j.neuron.2014.12.027

  View details for PubMedID 25569351

  View details for PubMedCentralID PMC4287959

• Spatiotemporal information during unsupervised learning enhances viewpoint invariant object recognition JOURNAL OF VISION Tian, M., Grill-Spector, K. 2015; 15 (6)

  Abstract

  Recognizing objects is difficult because it requires both linking views of an object that can be different and distinguishing objects with similar appearance. Interestingly, people can learn to recognize objects across views in an unsupervised way, without feedback, just from the natural viewing statistics. However, there is intense debate regarding what information during unsupervised learning is used to link among object views. Specifically, researchers argue whether temporal proximity, motion, or spatiotemporal continuity among object views during unsupervised learning is beneficial. Here, we untangled the role of each of these factors in unsupervised learning of novel three-dimensional (3-D) objects. We found that after unsupervised training with 24 object views spanning a 180° view space, participants showed significant improvement in their ability to recognize 3-D objects across rotation. Surprisingly, there was no advantage to unsupervised learning with spatiotemporal continuity or motion information than training with temporal proximity. However, we discovered that when participants were trained with just a third of the views spanning the same view space, unsupervised learning via spatiotemporal continuity yielded significantly better recognition performance on novel views than learning via temporal proximity. These results suggest that while it is possible to obtain view-invariant recognition just from observing many views of an object presented in temporal proximity, spatiotemporal information enhances performance by producing representations with broader view tuning than learning via temporal association. Our findings have important implications for theories of object recognition and for the development of computational algorithms that learn from examples.

  View details for DOI 10.1167/15.6.7

  View details for Web of Science ID 000357858600007

  View details for PubMedID 26024454

  View details for PubMedCentralID PMC4429262

• Electrical Stimulation of the Left and Right Human Fusiform Gyrus Causes Different Effects in Conscious Face Perception JOURNAL OF NEUROSCIENCE Rangarajan, V., Hermes, D., Foster, B. L., Weiner, K. S., Jacques, C., Grill-Spector, K., Parvizi, J. 2014; 34 (38): 12828-12836

  Abstract

  Neuroimaging and electrophysiological studies across species have confirmed bilateral face-selective responses in the ventral temporal cortex (VTC) and prosopagnosia is reported in patients with lesions in the VTC including the fusiform gyrus (FG). As imaging and electrophysiological studies provide correlative evidence, and brain lesions often comprise both white and gray matter structures beyond the FG, we designed the current study to explore the link between face-related electrophysiological responses in the FG and the causal effects of electrical stimulation of the left or right FG in face perception. We used a combination of electrocorticography (ECoG) and electrical brain stimulation (EBS) in 10 human subjects implanted with intracranial electrodes in either the left (5 participants, 30 FG sites) or right (5 participants, 26 FG sites) hemispheres. We identified FG sites with face-selective ECoG responses, and recorded perceptual reports during EBS of these sites. In line with existing literature, face-selective ECoG responses were present in both left and right FG sites. However, when the same sites were stimulated, we observed a striking difference between hemispheres. Only EBS of the right FG caused changes in the conscious perception of faces, whereas EBS of strongly face-selective regions in the left FG produced non-face-related visual changes, such as phosphenes. This study examines the relationship between correlative versus causal nature of ECoG and EBS, respectively, and provides important insight into the differential roles of the right versus left FG in conscious face perception.

  View details for DOI 10.1523/JNEUROSCI.0527-14.2014

  View details for Web of Science ID 000341767800019

  View details for PubMedCentralID PMC4166163

• Electrical stimulation of the left and right human fusiform gyrus causes different effects in conscious face perception. journal of neuroscience Rangarajan, V., Hermes, D., Foster, B. L., Weiner, K. S., Jacques, C., Grill-Spector, K., Parvizi, J. 2014; 34 (38): 12828-12836

  Abstract

  Neuroimaging and electrophysiological studies across species have confirmed bilateral face-selective responses in the ventral temporal cortex (VTC) and prosopagnosia is reported in patients with lesions in the VTC including the fusiform gyrus (FG). As imaging and electrophysiological studies provide correlative evidence, and brain lesions often comprise both white and gray matter structures beyond the FG, we designed the current study to explore the link between face-related electrophysiological responses in the FG and the causal effects of electrical stimulation of the left or right FG in face perception. We used a combination of electrocorticography (ECoG) and electrical brain stimulation (EBS) in 10 human subjects implanted with intracranial electrodes in either the left (5 participants, 30 FG sites) or right (5 participants, 26 FG sites) hemispheres. We identified FG sites with face-selective ECoG responses, and recorded perceptual reports during EBS of these sites. In line with existing literature, face-selective ECoG responses were present in both left and right FG sites. However, when the same sites were stimulated, we observed a striking difference between hemispheres. Only EBS of the right FG caused changes in the conscious perception of faces, whereas EBS of strongly face-selective regions in the left FG produced non-face-related visual changes, such as phosphenes. This study examines the relationship between correlative versus causal nature of ECoG and EBS, respectively, and provides important insight into the differential roles of the right versus left FG in conscious face perception.

  View details for DOI 10.1523/JNEUROSCI.0527-14.2014

  View details for PubMedID 25232118

• Where Is Human V4? Predicting the Location of hV4 and VO1 from Cortical Folding. Cerebral cortex Witthoft, N., Nguyen, M. L., Golarai, G., LaRocque, K. F., Liberman, A., Smith, M. E., Grill-Spector, K. 2014; 24 (9): 2401-2408

  Abstract

  A strong relationship between cortical folding and the location of primary sensory areas in the human brain is well established. However, it is unknown if coupling between functional responses and gross anatomy is found at higher stages of sensory processing. We examined the relationship between cortical folding and the location of the retinotopic maps hV4 and VO1, which are intermediate stages in the human ventral visual processing stream. Our data show a consistent arrangement of the eccentricity maps within hV4 and VO1 with respect to anatomy, with the consequence that the hV4/VO1 boundary is found consistently in the posterior transverse collateral sulcus (ptCoS) despite individual variability in map size and cortical folding. Understanding this relationship allowed us to predict the location of visual areas hV4 and VO1 in a separate set of individuals, using only their anatomies, with >85% accuracy. These findings have important implications for understanding the relation between cortical folding and functional maps as well as for defining visual areas from anatomical landmarks alone.

  View details for DOI 10.1093/cercor/bht092

  View details for PubMedID 23592823

• The functional architecture of the ventral temporal cortex and its role in categorization. Nature reviews. Neuroscience Grill-Spector, K., Weiner, K. S. 2014; 15 (8): 536-548

  Abstract

  Visual categorization is thought to occur in the human ventral temporal cortex (VTC), but how this categorization is achieved is still largely unknown. In this Review, we consider the computations and representations that are necessary for categorization and examine how the microanatomical and macroanatomical layout of the VTC might optimize them to achieve rapid and flexible visual categorization. We propose that efficient categorization is achieved by organizing representations in a nested spatial hierarchy in the VTC. This spatial hierarchy serves as a neural infrastructure for the representational hierarchy of visual information in the VTC and thereby enables flexible access to category information at several levels of abstraction.

  View details for DOI 10.1038/nrn3747

  View details for PubMedID 24962370

• The mid-fusiform sulcus: A landmark identifying both cytoarchitectonic and functional divisions of human ventral temporal cortex NEUROIMAGE Weiner, K. S., Golarai, G., Caspers, J., Chuapoco, M. R., Mohlberg, H., Zilles, K., Amunts, K., Grill-Spector, K. 2014; 84: 453-465

  Abstract

  Human ventral temporal cortex (VTC) plays a pivotal role in high-level vision. An under-studied macroanatomical feature of VTC is the mid-fusiform sulcus (MFS), a shallow longitudinal sulcus separating the lateral and medial fusiform gyrus (FG). Here, we quantified the morphological features of the MFS in 69 subjects (ages 7-40), and investigated its relationship to both cytoarchitectonic and functional divisions of VTC with four main findings. First, despite being a minor sulcus, we found that the MFS is a stable macroanatomical structure present in all 138 hemispheres with morphological characteristics developed by age 7. Second, the MFS is the locus of a lateral-medial cytoarchitectonic transition within the posterior FG serving as the boundary between cytoarchitectonic regions FG1 and FG2. Third, the MFS predicts a lateral-medial functional transition in eccentricity bias representations in children, adolescents, and adults. Fourth, the anterior tip of the MFS predicts the location of a face-selective region, mFus-faces/FFA-2. These findings are the first to illustrate that a macroanatomical landmark identifies both cytoarchitectonic and functional divisions of high-level sensory cortex in humans and have important implications for understanding functional and structural organization in the human brain.

  View details for DOI 10.1016/j.neuroimage.2013.08.068

  View details for Web of Science ID 000328868600042

  View details for PubMedID 24021838

• Abstracts of Presentations at the International Conference on Basic and Clinical Multimodal Imaging (BaCI), a Joint Conference of the International Society for Neuroimaging in Psychiatry (ISNIP), the International Society for Functional Source Imaging (ISFSI), the International Society for Bioelectromagnetism (ISBEM), the International Society for Brain Electromagnetic Topography (ISBET), and the EEG and Clinical Neuroscience Society (ECNS), in Geneva, Switzerland, September 5-8, 2013. Clinical EEG and neuroscience He, B. J., Nolte, G., Nagata, K., Takano, D., Yamazaki, T., Fujimaki, Y., Maeda, T., Satoh, Y., Heckers, S., George, M. S., Lopes Da Silva, F., De Munck, J. C., van Houdt, P. J., Verdaasdonk, R. M., Ossenblok, P., Mullinger, K., Bowtell, R., Bagshaw, A. P., Keeser, D., Karch, S., Segmiller, F., HANTSCHK, I., Berman, A., Padberg, F., Pogarell, O., Scharnowski, F., Karch, S., Hümmer, S., Keeser, D., Paolini, M., Kirsch, V., Koller, G., Rauchmann, B., Kupka, M., Blautzik, J., Pogarell, O., Razavi, N., JANN, K., Koenig, T., Kottlow, M., Hauf, M., Strik, W., Dierks, T., Gotman, J., Vulliemoz, S., Lu, Y., Zhang, H., Yang, L., Worrell, G., He, B., Gruber, O., Piguet, C., Hubl, D., Homan, P., Kindler, J., Dierks, T., Kim, K., Steinhoff, U., Wakai, R., Koenig, T., Kottlow, M., Melie-García, L., Mucci, A., Volpe, U., Prinster, A., Salvatore, M., Galderisi, S., Linden, D. E., Brandeis, D., Schroeder, C. E., Kayser, C., Panzeri, S., Kleinschmidt, A., Ritter, P., Walther, S., Haueisen, J., Lau, S., Flemming, L., Sonntag, H., Maess, B., Knösche, T. R., Lanfer, B., Dannhauer, M., Wolters, C. H., Stenroos, M., Haueisen, J., Wolters, C., Aydin, U., Lanfer, B., LEW, S., Lucka, F., Ruthotto, L., Vorwerk, J., Wagner, S., Ramon, C., Guan, C., Ang, K. K., Chua, S. G., Kuah, W. K., Phua, K. S., Chew, E., Zhou, H., Chuang, K. H., Ang, B. T., Wang, C., Zhang, H., Yang, H., Chin, Z. Y., Yu, H., Pan, Y., Collins, L., Mainsah, B., COLWELL, K., Morton, K., Ryan, D., Sellers, E., CAVES, K., Throckmorton, S., Kübler, A., Holz, E. M., Zickler, C., Sellers, E., Ryan, D., BROWN, K., COLWELL, K., Mainsah, B., CAVES, K., Throckmorton, S., Collins, L., Wennberg, R., Ahlfors, S. P., Grova, C., Chowdhury, R., HEDRICH, T., Heers, M., Zelmann, R., Hall, J. A., Lina, J. M., Kobayashi, E., Oostendorp, T., van Dam, P., Oosterhof, P., Linnenbank, A., Coronel, R., van Dessel, P., de Bakker, J., Rossion, B., Jacques, C., Witthoft, N., Weiner, K. S., Foster, B. L., Miller, K. J., Hermes, D., Parvizi, J., Grill-Spector, K., Recanzone, G. H., Murray, M. M., Haynes, J. D., Richiardi, J., Greicius, M., De Lucia, M., Müller, K., Formisano, E., Smieskova, R., Schmidt, A., Bendfeldt, K., Walter, A., Riecher-Rössler, A., Borgwardt, S., Fusar-Poli, P., Eliez, S., Schmidt, A., Sekihara, K., Nagarajan, S. S., Schoffelen, J. M., Guggisberg, A. G., Nolte, G., Balazs, S., Kermanshahi, K., Kiesenhofer, W., Binder, H., Rattay, F., Antal, A., Chaieb, L., Paulus, W., Bodis-Wollner, I., Maurer, K., Fein, G., Camchong, J., Johnstone, J., Cardenas-Nicolson, V., Fiederer, L. D., Lucka, F., Yang, S., Vorwerk, J., Dümpelmann, M., Cosandier-Rimélé, D., Schulze-Bonhage, A., Aertsen, A., Speck, O., Wolters, C. H., Ball, T., Fuchs, M., Wagner, M., Kastner, J., Tech, R., Dinh, C., Haueisen, J., Baumgarten, D., Hämäläinen, M. S., Lau, S., Vogrin, S. J., D'Souza, W., Haueisen, J., Cook, M. J., Custo, A., Van de Ville, D., Vulliemoz, S., Grouiller, F., Michel, C. M., Malmivuo, J., Aydin, U., Vorwerk, J., Küpper, P., Heers, M., Kugel, H., Wellmer, J., Kellinghaus, C., Scherg, M., Rampp, S., Wolters, C., Storti, S. F., Boscolo Galazzo, I., Del Felice, A., Pizzini, F. B., Arcaro, C., Formaggio, E., Mai, R., Manganotti, P., Koessler, L., Vignal, J., CECCHIN, T., Colnat-Coulbois, S., Vespignani, H., Ramantani, G., Maillard, L., Rektor, I., Kuba, R., Brázdil, M., Chrastina, J., Rektorova, I., Van Mierlo, P., Carrette, E., Strobbe, G., Montes-Restrepo, V., Vonck, K., Vandenberghe, S., Ahmed, B., Brodely, C., Carlson, C., Kuzniecky, R., Devinsky, O., French, J., Thesen, T., Bénis, D., David, O., Lachaux, J., Seigneuret, E., Krack, P., Fraix, V., Chabardès, S., Bastin, J., JANN, K., Gee, D., Kilroy, E., Cannon, T., Wang, D. J., Hale, J. R., Mayhew, S. D., Przezdzik, I., Arvanitis, T. N., Bagshaw, A. P., Plomp, G., Quairiaux, C., Astolfi, L., Michel, C. M., Mayhew, S. D., Mullinger, K. J., Bagshaw, A. P., Bowtell, R., Francis, S. T., Schouten, A. C., Campfens, S. F., van der Kooij, H., Koles, Z., Lind, J., Flor-Henry, P., Wirth, M., HAASE, C. M., Villeneuve, S., Vogel, J., Jagust, W. J., Kambeitz-Ilankovic, L., Simon-Vermot, L., Gesierich, B., Duering, M., Ewers, M., Rektorova, I., Krajcovicova, L., Marecek, R., Mikl, M., Bracht, T., Horn, H., Strik, W., Federspiel, A., Schnell, S., Höfle, O., Stegmayer, K., Wiest, R., Dierks, T., Müller, T. J., Walther, S., Surmeli, T., Ertem, A., Eralp, E., Kos, I. H., Skrandies, W., Flüggen, S., Klein, A., Britz, J., Díaz Hernàndez, L., Ro, T., Michel, C. M., Lenartowicz, A., Lau, E., Rodriguez, C., Cohen, M. S., Loo, S. K., Di Lorenzo, G., Pagani, M., Monaco, L., Daverio, A., Giannoudas, I., La Porta, P., Verardo, A. R., Niolu, C., Fernandez, I., Siracusano, A., Flor-Henry, P., Lind, J., Koles, Z., Bollmann, S., Ghisleni, C., O'Gorman, R., Poil, S., Klaver, P., Michels, L., Martin, E., Ball, J., Eich-Höchli, D., Brandeis, D., Salisbury, D. F., Murphy, T. K., Butera, C. D., Mathalon, D. H., Fryer, S. L., Kiehl, K. A., Calhoun, V. C., Pearlson, G. D., Roach, B. J., Ford, J. M., McGlashan, T. H., Woods, S. W., Volpe, U., Merlotti, E., Vignapiano, A., Montefusco, V., Plescia, G. M., Gallo, O., Romano, P., Mucci, A., Galderisi, S., Mingoia, G., Langbein, K., Dietzek, M., Wagner, G., Smesny, Scherpiet, S., Maitra, R., Gaser, C., Sauer, H., Nenadic, I., Gonzalez Andino, S., Grave de Peralta Menendez, R., Grave de Peralta Menendez, R., Sanchez Vives, M., Rebollo, B., Gonzalez Andino, S., Frølich, L., Andersen, T. S., Mørup, M., Belfiore, P., Gargiulo, P., Ramon, C., Vanhatalo, S., Cho, J., Vorwerk, J., Wolters, C. H., Knösche, T. R., Watanabe, T., Kawabata, Y., Ukegawa, D., Kawabata, S., Adachi, Y., Sekihara, K., Sekihara, K., Nagarajan, S. S., Wagner, S., Aydin, U., Vorwerk, J., Herrmann, C., Burger, M., Wolters, C., Lucka, F., Aydin, U., Vorwerk, J., Burger, M., Wolters, C., Bauer, M., Trahms, L., Sander, T., Faber, P. L., Lehmann, D., Gianotti, L. R., Pascual-Marqui, R. D., Milz, P., Kochi, K., Kaneko, S., Yamashita, S., Yana, K., Kalogianni, K., Vardy, A. N., Schouten, A. C., Van Der Helm, F. C., Sorrentino, A., Luria, G., Aramini, R., Hunold, A., Funke, M., Eichardt, R., Haueisen, J., Gómez-Aguilar, F., Vázquez-Olvera, S., Cordova-Fraga, T., Castro-López, J., Hernández-Gonzalez, M. A., Solorio-Meza, S., Sosa-Aquino, M., Bernal-Alvarado, J. J., Vargas-Luna, M., Vorwerk, J., Magyari, L., Ludewig, J., Oostenveld, R., Wolters, C. H., Vorwerk, J., Engwer, C., Ludewig, J., Wolters, C., Sato, K., Nishibe, T., Furuya, M., Yamashiro, K., Yana, K., Ono, T., Puthanmadam Subramaniyam, N., Hyttinen, J., Lau, S., Güllmar, D., Flemming, L., Haueisen, J., Sonntag, H., Vorwerk, J., Wolters, C. H., Grasedyck, L., Haueisen, J., Maeß, B., Freitag, S., Graichen, U., FIEDLER, P., Strohmeier, D., Haueisen, J., Stenroos, M., Hauk, O., Grigutsch, M., Felber, M., Maess, B., Herrmann, B., Strobbe, G., Van Mierlo, P., Vandenberghe, S., Strobbe, G., Cárdenas-Peña, D., Montes-Restrepo, V., Van Mierlo, P., Castellanos-Dominguez, G., Vandenberghe, S., Lanfer, B., Paul-Jordanov, I., Scherg, M., Wolters, C. H., Ito, Y., Sato, D., Kamada, K., Kobayashi, T., Dalal, S. S., Rampp, S., Willomitzer, F., Arold, O., Fouladi-Movahed, S., Häusler, G., Stefan, H., Ettl, S., Zhang, S., Zhang, Y., Li, H., Kong, X., Montes-Restrepo, V., Strobbe, G., Van Mierlo, P., Vandenberghe, S., Wong, D. D., Bidet-Caulet, A., Knight, R. T., Crone, N. E., Dalal, S. S., Birot, G., Spinelli, L., Vulliémoz, S., Seeck, M., Michel, C. M., Emory, H., Wells, C., Mizrahi, N., Vogrin, S. J., Lau, S., Cook, M. J., Karahanoglu, F. I., Grouiller, F., Caballero-Gaudes, C., Seeck, M., Vulliemoz, S., Van de Ville, D., Spinelli, L., Megevand, P., Genetti, M., Schaller, K., Michel, C., Vulliemoz, S., Seeck, M., Genetti, M., Tyrand, R., Grouiller, F., Vulliemoz, S., Spinelli, L., Seeck, M., Schaller, K., Michel, C. M., Grouiller, F., Heinzer, S., DELATTRE, B., Lazeyras, F., Spinelli, L., Pittau, F., Seeck, M., Ratib, O., Vargas, M., Garibotto, V., Vulliemoz, S., Vogrin, S. J., Bailey, C. A., Kean, M., Warren, A. E., Davidson, A., Seal, M., Harvey, A. S., Archer, J. S., Papadopoulou, M., Leite, M., Van Mierlo, P., Vonck, K., Boon, P., Friston, K., Marinazzo, D., Ramon, C., Holmes, M., Koessler, L., Rikir, E., Gavaret, M., Bartolomei, F., Vignal, J. P., Vespignani, H., Maillard, L., Centeno, M., Perani, S., Pier, K., Lemieux, L., Clayden, J., Clark, C., Pressler, R., Cross, H., Carmichael, D. W., Spring, A., Bessemer, R., Pittman, D., Aghakhani, Y., Federico, P., Pittau, F., Grouiller, F., Vulliémoz, S., Gotman, J., Badier, J. M., Bénar, C., Bartolomei, F., Cruto, C., Chauvel, P., Gavaret, M., Brodbeck, V., Van Leeuwen, T., Tagliazzuchi, E., Melloni, L., Laufs, H., Griskova-Bulanova, I., Dapsys, K., Klein, C., Hänggi, J., Jäncke, L., Ehinger, B. V., Fischer, P., Gert, A. L., KAUFHOLD, L., Weber, F., Marchante Fernandez, M., Pipa, G., König, P., Sekihara, K., Hiyama, E., Koga, R., Iannilli, E., Michel, C. M., Bartmuss, A., Gupta, N., Hummel, T., Boecker, R., Holz, N., Buchmann, A. F., Blomeyer, D., Plichta, M. M., Wolf, I., Baumeister, S., Meyer-Lindenberg, A., Banaschewski, T., Brandeis, D., Laucht, M., Natahara, S., Ueno, M., Kobayashi, T., Kottlow, M., Bänninger, A., Koenig, T., Schwab, S., Koenig, T., Federspiel, A., Dierks, T., JANN, K., Natsukawa, H., Kobayashi, T., Tüshaus, L., Koenig, T., Kottlow, M., Achermann, P., Wilson, R. S., Mayhew, S. D., Assecondi, S., Arvanitis, T. N., Bagshaw, A. P., Darque, A., Rihs, T. A., Grouiller, F., Lazeyras, F., Ha-Vinh Leuchter, R., Caballero, C., Michel, C. M., Hüppi, P. S., Hauser, T. U., Hunt, L. T., Iannaccone, R., Stämpfli, P., Brandeis, D., DOLAN, R. J., Walitza, S., Brem, S., Graichen, U., Eichardt, R., FIEDLER, P., Strohmeier, D., Freitag, S., Zanow, F., Haueisen, J., Lordier, L., Grouiller, F., Van de Ville, D., Sancho Rossignol, A., Cordero, I., Lazeyras, F., Ansermet, F., Hüppi, P., Schläpfer, A., Rubia, K., Brandeis, D., Di Lorenzo, G., Pagani, M., Monaco, L., Daverio, A., Giannoudas, I., Verardo, A. R., La Porta, P., Niolu, C., Fernandez, I., Siracusano, A., Tamura, K., Karube, C., Mizuba, T., Matsufuji, M., Takashima, S., Iramina, K., Assecondi, S., Ostwald, D., Bagshaw, A. P., Marecek, R., Brazdil, M., LAMOS, M., Slavícek, T., Marecek, R., Jan, J., Meier, N. M., Perrig, W., Koenig, T., Minami, T., Noritake, Y., Nakauchi, S., Azuma, K., Minami, T., Nakauchi, S., Rodriguez, C., Lenartowicz, A., Cohen, M. S., Rodriguez, C., Lenartowicz, A., Cohen, M. S., Iramina, K., Kinoshita, H., Tamura, K., Karube, C., Kaneko, M., Ide, J., Noguchi, Y., Cohen, M. S., Douglas, P. K., Rodriguez, C. M., Xia, H. J., Zimmerman, E. M., Konopka, C. J., EPSTEIN, P. S., Konopka, L. M., GIEZENDANNER, S., Fisler, M., Soravia, L., Andreotti, J., Wiest, R., Dierks, T., Federspiel, A., Razavi, N., Federspiel, A., Dierks, T., Hauf, M., JANN, K., Kamada, K., Sato, D., Ito, Y., Okano, K., Mizutani, N., Kobayashi, T., Thelen, A., Murray, M., Pastena, L., Formaggio, E., Storti, S. F., Faralli, F., Melucci, M., Gagliardi, R., Ricciardi, L., RUFFINO, G., Coito, A., MACKU, P., Tyrand, R., Astolfi, L., He, B., Wiest, R., Seeck, M., Michel, C., Plomp, G., Vulliemoz, S., Fischmeister, F. P., Glaser, J., Schöpf, V., Bauer, H., Beisteiner, R., Deligianni, F., Centeno, M., Carmichael, D. W., Clayden, J., Mingoia, G., Langbein, K., Dietzek, M., Wagner, G., Smesny, S., Scherpiet, S., Maitra, R., Gaser, C., Sauer, H., Nenadic, I., Dürschmid, S., Zaehle, T., Pannek, H., Chang, H. F., Voges, J., Rieger, J., Knight, R. T., Heinze, H., Hinrichs, H., Tsatsishvili, V., Cong, F., Puoliväli, T., Alluri, V., Toiviainen, P., Nandi, A. K., Brattico, E., Ristaniemi, T., GRIEDER, M., Crinelli, R. M., JANN, K., Federspiel, A., Wirth, M., Koenig, T., Stein, M., Wahlund, L., Dierks, T., Atsumori, H., Yamaguchi, R., Okano, Y., Sato, H., Funane, T., Sakamoto, K., Kiguchi, M., Tränkner, A., Schindler, S., Schmidt, F., Strauß, M., Trampel, R., Hegerl, U., Turner, R., Geyer, S., Schönknecht, P., Kebets, V., Van Assche, M., Goldstein, R., van der Meulen, M., Vuilleumier, P., Richiardi, J., Van de Ville, D., Assal, F., Wozniak-Kwasniewska, A., Szekely, D., Harquel, S., Bougerol, T., David, O., Bracht, T., Jones, D. K., Horn, H., Müller, T. J., Walther, S., Sos, P., Klirova, M., Novak, T., Brunovsky, M., Horacek, J., Bares, M., Hoschl C, C., Fellhauer, I., Zöllner, F. G., Schröder, J., Kong, L., Essig, M., Schad, L. R., Arrubla, J., Neuner, I., Hahn, D., Boers, F., Shah, N. J., Neuner, I., Arrubla, J., Hahn, D., Boers, F., Jon Shah, N., Suriya Prakash, M., Sharma, R., Kawaguchi, H., Kobayashi, T., FIEDLER, P., Griebel, S., Biller, S., Fonseca, C., Vaz, F., Zentner, L., Zanow, F., Haueisen, J., Rochas, V., RIHS, T., Thut, G., Rosenberg, N., Landis, T., Michel, C., Moliadze, V., Schmanke, T., Lyzhko, E., Bassüner, S., Freitag, C., Siniatchkin, M., Thézé, R., Guggisberg, A. G., Nahum, L., Schnider, A., Meier, L., Friedrich, H., JANN, K., Landis, B., Wiest, R., Federspiel, A., Strik, W., Dierks, T., Witte, M., Kober, S. E., Neuper, C., Wood, G., König, R., MATYSIAK, A., Kordecki, W., Sieluzycki, C., Zacharias, N., Heil, P., Wyss, C., Boers, F., Arrubla, J., Dammers, J., Kawohl, W., Neuner, I., Shah, N. J., Braboszcz, C., Cahn, R. B., Levy, J., Fernandez, M., Delorme, A., Rosas-Martinez, L., Milne, E., Zheng, Y., Urakami, Y., Kawamura, K., WASHIZAWA, Y., Hiyoshi, K., Cichocki, A., Giroud, N., Dellwo, V., Meyer, M., Rufener, K. S., LIEM, F., Dellwo, V., Meyer, M., Jones-Rounds, J. D., Raizada, R., Staljanssens, W., Strobbe, G., Van Mierlo, P., Van Holen, R., Vandenberghe, S., Pefkou, M., Becker, R., Michel, C., Hervais-Adelman, A., He, W., Brock, J., Johnson, B., Ohla, K., HITZ, K., Heekeren, K., Obermann, C., Huber, T., Juckel, G., Kawohl, W., Gabriel, D., Comte, A., Henriques, J., MAGNIN, E., Grigoryeva, L., Ortega, J., Haffen, E., Moulin, T., Pazart, L., Aubry, R., Kukleta, M., Baris Turak, B., Louvel, J., Crespo-Garcia, M., Cantero, J. L., Atienza, M., Connell, S., Kilborn, K., Damborská, A., Brázdil, M., Rektor, I., Kukleta, M., Koberda, J. L., Bienkiewicz, A., Koberda, I., Koberda, P., Moses, A., Tomescu, M., RIHS, T., Britz, J., Custo, A., Grouiller, F., Schneider, M., Debbané, M., Eliez, S., Michel, C., Wang, G. Y., Kydd, R., Wouldes, T. A., Jensen, M., Russell, B. R., Dissanayaka, N., Au, T., Angwin, A., O'Sullivan, J., Byrne, G., Silburn, P., Marsh, R., Mellic, G., Copland, D., Bänninger, A., Kottlow, M., Díaz Hernàndez, L., Koenig, T., Díaz Hernàndez, L., Bänninger, A., Koenig, T., Hauser, T. U., Iannaccone, R., Mathys, C., Ball, J., Drechsler, R., Brandeis, D., Walitza, S., Brem, S., Boeijinga, P. H., Pang, E. W., Valica, T., MacDonald, M. J., Oh, A., Lerch, J. P., Anagnostou, E., Di Lorenzo, G., Pagani, M., Monaco, L., Daverio, A., Verardo, A. R., Giannoudas, I., La Porta, P., Niolu, C., Fernandez, I., Siracusano, A., Shimada, T., Matsuda, Y., Monkawa, A., Monkawa, T., Hashimoto, R., Watanabe, K., Kawasaki, Y., Matsuda, Y., Shimada, T., Monkawa, T., Monkawa, A., Watanabe, K., Kawasaki, Y., Stegmayer, K., Horn, H., Federspiel, A., Razavi, N., Bracht, T., Laimböck, K., Strik, W., Dierks, T., Wiest, R., Müller, T. J., Walther, S., Koorenhof, L. J., Swithenby, S. J., Martins-Mourao, A., Rihs, T. A., Tomescu, M., Song, K. W., Custo, A., Knebel, J. F., Murray, M., Eliez, S., Michel, C. M., Volpe, U., Merlotti, E., Vignapiano, A., Montefusco, V., Plescia, G. M., Gallo, O., Romano, P., Mucci, A., Galderisi, S., Laimboeck, K., JANN, K., Walther, S., Federspiel, A., Wiest, R., Strik, W., Horn, H. 2013: -?

  View details for PubMedID 24368763

• Global Similarity and Pattern Separation in the Human Medial Temporal Lobe Predict Subsequent Memory JOURNAL OF NEUROSCIENCE LaRocque, K. F., Smith, M. E., Carr, V. A., Witthoft, N., Grill-Spector, K., Wagner, A. D. 2013; 33 (13): 5466-5474

  Abstract

  Intense debate surrounds the role of medial temporal lobe (MTL) structures in recognition memory. Using high-resolution fMRI and analyses of pattern similarity in humans, we examined the encoding computations subserved by MTL subregions. Specifically, we tested the theory that MTL cortex supports memory by encoding overlapping representations, whereas hippocampus supports memory by encoding pattern-separated representations. Consistent with this view, the relationship between encoding pattern similarity and subsequent memory dissociated MTL cortex and hippocampus: later memory was predicted by greater across-item pattern similarity in perirhinal cortex and in parahippocampal cortex, but greater pattern distinctiveness in hippocampus. Additionally, by comparing neural patterns elicited by individual stimuli regardless of subsequent memory, we found that perirhinal cortex and parahippocampal cortex exhibited differential content sensitivity for multiple stimulus categories, whereas hippocampus failed to demonstrate content sensitivity. These data provide novel evidence that complementary MTL encoding computations subserve declarative memory.

  View details for DOI 10.1523/JNEUROSCI.4293-12.2013

  View details for Web of Science ID 000316948600005

  View details for PubMedID 23536062

  View details for PubMedCentralID PMC3643502

• Neural representations of faces and limbs neighbor in human high-level visual cortex: evidence for a new organization principle PSYCHOLOGICAL RESEARCH-PSYCHOLOGISCHE FORSCHUNG Weiner, K. S., Grill-Spector, K. 2013; 77 (1): 74-97

  Abstract

  Neurophysiology and optical imaging studies in monkeys and functional magnetic resonance imaging (fMRI) studies in both monkeys and humans have localized clustered neural responses in inferotemporal cortex selective for images of biologically relevant categories, such as faces and limbs. Using higher resolution (1.5 mm voxels) fMRI scanning methods than past studies (3-5 mm voxels), we recently reported a network of multiple face- and limb-selective regions that neighbor one another in human ventral temporal cortex (Weiner and Grill-Spector, Neuroimage, 52(4):1559-1573, 2010) and lateral occipitotemporal cortex (Weiner and Grill-Spector, Neuroimage, 56(4):2183-2199, 2011). Here, we expand on three basic organization principles of high-level visual cortex revealed by these findings: (1) consistency in the anatomical location of functional regions, (2) preserved spatial relationship among functional regions, and (3) a topographic organization of face- and limb-selective regions in adjacent and alternating clusters. We highlight the implications of this structure in comparing functional brain organization between typical and atypical populations. We conclude with a new model of high-level visual cortex consisting of ventral, lateral, and dorsal components, where multimodal processing related to vision, action, haptics, and language converges in the lateral pathway.

  View details for DOI 10.1007/s00426-011-0392-x

  View details for Web of Science ID 000313053700008

  View details for PubMedID 22139022

  View details for PubMedCentralID PMC3535411

• THE FUSIFORM GYRUS REPRESENTS THE AGE OF FACES Golarai, G., Liberman, A., Grill-Spector, K. MIT PRESS. 2013: 205

  View details for Web of Science ID 000317030501154

• Electrical Stimulation of Human Fusiform Face-Selective Regions Distorts Face Perception JOURNAL OF NEUROSCIENCE Parvizi, J., Jacques, C., Foster, B. L., Withoft, N., Rangarajan, V., Weiner, K. S., Grill-Spector, K. 2012; 32 (43): 14915-14920

  Abstract

  Face-selective neural responses in the human fusiform gyrus have been widely examined. However, their causal role in human face perception is largely unknown. Here, we used a multimodal approach of electrocorticography (ECoG), high-resolution functional magnetic resonance imaging (fMRI), and electrical brain stimulation (EBS) to directly investigate the causal role of face-selective neural responses of the fusiform gyrus (FG) in face perception in a patient implanted with subdural electrodes in the right inferior temporal lobe. High-resolution fMRI identified two distinct FG face-selective regions [mFus-faces and pFus-faces (mid and posterior fusiform, respectively)]. ECoG revealed a striking anatomical and functional correspondence with fMRI data where a pair of face-selective electrodes, positioned 1 cm apart, overlapped mFus-faces and pFus-faces, respectively. Moreover, electrical charge delivered to this pair of electrodes induced a profound face-specific perceptual distortion during viewing of real faces. Specifically, the subject reported a "metamorphosed" appearance of faces of people in the room. Several controls illustrate the specificity of the effect to the perception of faces. EBS of mFus-faces and pFus-faces neither produced a significant deficit in naming pictures of famous faces on the computer, nor did it affect the appearance of nonface objects. Further, the appearance of faces remained unaffected during both sham stimulation and stimulation of a pair of nearby electrodes that were not face-selective. Overall, our findings reveal a striking convergence of fMRI, ECoG, and EBS, which together offer a rare causal link between functional subsets of the human FG network and face perception.

  View details for DOI 10.1523/JNEUROSCI.2609-12.2012

  View details for Web of Science ID 000310523900008

  View details for PubMedID 23100414

  View details for PubMedCentralID PMC3517886

• Face-likeness and image variability drive responses in human face-selective ventral regions HUMAN BRAIN MAPPING Davidenko, N., Remus, D. A., Grill-Spector, K. 2012; 33 (10): 2334-2349

  Abstract

  The human ventral visual stream contains regions that respond selectively to faces over objects. However, it is unknown whether responses in these regions correlate with how face-like stimuli appear. Here, we use parameterized face silhouettes to manipulate the perceived face-likeness of stimuli and measure responses in face- and object-selective ventral regions with high-resolution fMRI. We first use "concentric hyper-sphere" (CH) sampling to define face silhouettes at different distances from the prototype face. Observers rate the stimuli as progressively more face-like the closer they are to the prototype face. Paradoxically, responses in both face- and object-selective regions decrease as face-likeness ratings increase. Because CH sampling produces blocks of stimuli whose variability is negatively correlated with face-likeness, this effect may be driven by more adaptation during high face-likeness (low-variability) blocks than during low face-likeness (high-variability) blocks. We tested this hypothesis by measuring responses to matched-variability (MV) blocks of stimuli with similar face-likeness ratings as with CH sampling. Critically, under MV sampling, we find a face-specific effect: responses in face-selective regions gradually increase with perceived face-likeness, but responses in object-selective regions are unchanged. Our studies provide novel evidence that face-selective responses correlate with the perceived face-likeness of stimuli, but this effect is revealed only when image variability is controlled across conditions. Finally, our data show that variability is a powerful factor that drives responses across the ventral stream. This indicates that controlling variability across conditions should be a critical tool in future neuroimaging studies of face and object representation.

  View details for DOI 10.1002/hbm.21367

  View details for Web of Science ID 000308589400007

  View details for PubMedID 21823208

  View details for PubMedCentralID PMC3404198

• White matter microstructure on diffusion tensor imaging is associated with conventional magnetic resonance imaging findings and cognitive function in adolescents born preterm DEVELOPMENTAL MEDICINE AND CHILD NEUROLOGY Feldman, H. M., Lee, E. S., Loe, I. M., Yeom, K. W., Grill-Spector, K., Luna, B. 2012; 54 (9): 809-814

  Abstract

  Diffusion tensor imaging (DTI) was used to evaluate white matter architecture after preterm birth. The goals were (1) to compare white matter microstructure in two cohorts of preterm- and term-born children; and (2) within preterm groups, to determine if sex, gestational age, birthweight, white matter injury score from conventional magnetic resonance imaging (MRI), or IQ was associated with DTI measures.Participants (n=121; 66 females, 55 males) were aged 9 to 16 years. They comprised 58 preterm children (site 1, n=25; and site 2, n=33) born at less than 36 weeks' gestation (mean 29.4 wks; birthweight 1289g) and 63 term children (site 1, n=40; site 2, n=23) born at more than 37 weeks' gestation. DTI was analyzed using tract-based spatial statistics. Diffusion measures were fractional anisotropy, axial, radial, and mean diffusivity.In no region of the white matter skeleton was fractional anisotropy lower in the preterm group at either site. Within the preterm groups, fractional anisotropy was significantly associated with white matter injury score, but not sex, gestational age, or birthweight. At site 1, fractional anisotropy was associated with IQ.DTI contributes to understanding individual differences after preterm birth but may not differentiate a relatively high-functioning group of preterm children from a matched group of term-born children.

  View details for DOI 10.1111/j.1469-8749.2012.04378.x

  View details for PubMedID 22803787

• Synchrony upon repetition: One or multiple neural mechanisms? Cognitive neuroscience Weiner, K. S., Grill-Spector, K. 2012; 3 (3-4): 243-4

  Abstract

  Abstract A central goal of cognitive neuroscience is to understand the relationship between repetition suppression (RS) and priming. Gotts and colleagues propose a new model examining this relationship where stimulus repetition produces increased neural synchronization, thus increasing the efficiency of neural responses and potentially explaining the characterizing features of both RS and priming. While synchrony is an appealing new model, we suggest that further constraints are necessary to account for qualitatively different types of RS and priming yet to be considered by the present implementation.

  View details for DOI 10.1080/17588928.2012.689973

  View details for PubMedID 24171750

• The improbable simplicity of the fusiform face area TRENDS IN COGNITIVE SCIENCES Weiner, K. S., Grill-Spector, K. 2012; 16 (5): 251-254

  Abstract

  The fusiform face area (FFA) is described as an easily identifiable module on the fusiform gyrus. However, the organization of face-selective regions in ventral temporal cortex (VTC) is more complex than this prevailing view. We highlight methodological factors contributing to these complexities and the extensive variability in how the FFA is identified. We suggest a series of constraints to aid researchers when defining any functionally specialized region with a pleasing realization: anatomy matters.

  View details for DOI 10.1016/j.tics.2012.03.003

  View details for Web of Science ID 000304026200001

  View details for PubMedID 22481071

• The Interplay between Feature-Saliency and Feedback Information in Visual Category Learning Tasks. CogSci ... Annual Conference of the Cognitive Science Society. Cognitive Science Society (U.S.). Conference Hammer, R., Sloutsky, V., Grill-Spector, K. 2012; 2012: 420-425

  Abstract

  What is the role of feedback information in different visual category learning (VCL) scenarios? To address this question we tested participants' performance in VCL tasks in which stimuli varied in three feature dimensions, one of which was relevant for the task and the other two were irrelevant. The relevant feature could be identified based on trial-by-trial feedback. In one condition the task relevant and irrelevant features were highly-salient. In the second condition all features had low-visual-saliency. Feedback information was also manipulated: In the high-information condition the task relevant feature could be identified by the information provided in each trial whereas in the mid-information condition the feedback was ambiguous and information from several learning trials was required in order to confidently identify the relevant feature. Surprisingly, our data shows that mid- and high-information feedback are similarly effective in high-saliency VCL tasks. In contrast, in low-saliency VCL tasks, mid-information feedback impairs learning. We suggest that VCL can be done effectively either when feedback is ambiguous or in low-saliency conditions, but not in scenarios when both challenges occur concurrently.

  View details for PubMedID 25346948

• Synchrony upon repetition: One or multiple neural mechanisms? COGNITIVE NEUROSCIENCE Weiner, K. S., Grill-Spector, K. 2012; 3 (3-4): 243-244

  Abstract

  Abstract A central goal of cognitive neuroscience is to understand the relationship between repetition suppression (RS) and priming. Gotts and colleagues propose a new model examining this relationship where stimulus repetition produces increased neural synchronization, thus increasing the efficiency of neural responses and potentially explaining the characterizing features of both RS and priming. While synchrony is an appealing new model, we suggest that further constraints are necessary to account for qualitatively different types of RS and priming yet to be considered by the present implementation.

  View details for DOI 10.1080/17588928.2012.689973

  View details for Web of Science ID 000306834600023

• Not one extrastriate body area: Using anatomical landmarks, hMT+, and visual field maps to parcellate limb-selective activations in human lateral occipitotemporal cortex NEUROIMAGE Weiner, K. S., Grill-Spector, K. 2011; 56 (4): 2183-2199

  Abstract

  The prevailing view of human lateral occipitotemporal cortex (LOTC) organization suggests a single area selective for images of the human body (extrastriate body area, EBA) that highly overlaps with the human motion-selective complex (hMT+). Using functional magnetic resonance imaging with higher resolution (1.5mm voxels) than past studies (3-4mm voxels), we examined the fine-scale spatial organization of these activations relative to each other, as well as to visual field maps in LOTC. Rather than one contiguous EBA highly overlapping hMT+, results indicate three limb-selective activations organized in a crescent surrounding hMT+: (1) an activation posterior to hMT+ on the lateral occipital sulcus/middle occipital gyrus (LOS/MOG) overlapping the lower vertical meridian shared between visual field maps LO-2 and TO-1, (2) an activation anterior to hMT+ on the middle temporal gyrus (MTG) consistently overlapping the lower vertical meridian of TO-2 and extending outside presently defined visual field maps, and (3) an activation inferior to hMT+ on the inferotemporal gyrus (ITG) overlapping the parafoveal representation of the TO cluster. This crescent organization of limb-selective activations surrounding hMT+ is reproducible over a span of three years and is consistent across different image types used for localization. Further, these regions exhibit differential position properties: preference for contralateral image presentation decreases and preference for foveal presentation increases from the limb-selective LOS to the MTG. Finally, the relationship between limb-selective activations and visual field maps extends to the dorsal stream where a posterior IPS activation overlaps V7. Overall, our measurements demonstrate a series of LOTC limb-selective activations that 1) have separate anatomical and functional boundaries, 2) overlap distinct visual field maps, and 3) illustrate differential position properties. These findings indicate that category selectivity alone is an insufficient organization principle for defining brain areas. Instead, multiple properties are necessary in order to parcellate and understand the functional organization of high-level visual cortex.

  View details for DOI 10.1016/j.neuroimage.2011.03.041

  View details for Web of Science ID 000291457500029

  View details for PubMedID 21439386

  View details for PubMedCentralID PMC3138128

• Sparsely-distributed organization of face and limb activations in human ventral temporal cortex NEUROIMAGE Weiner, K. S., Grill-Spector, K. 2010; 52 (4): 1559-1573

  Abstract

  Functional magnetic resonance imaging (fMRI) has identified face- and body part-selective regions, as well as distributed activation patterns for object categories across human ventral temporal cortex (VTC), eliciting a debate regarding functional organization in VTC and neural coding of object categories. Using high-resolution fMRI, we illustrate that face- and limb-selective activations alternate in a series of largely nonoverlapping clusters in lateral VTC along the inferior occipital gyrus (IOG), fusiform gyrus (FG), and occipito-temporal sulcus (OTS). Both general linear model (GLM) and multivoxel pattern (MVP) analyses show that face- and limb-selective activations minimally overlap and that this organization is consistent across experiments and days. We provide a reliable method to separate two face-selective clusters on the middle and posterior FG (mFus and pFus), and another on the IOG using their spatial relation to limb-selective activations and retinotopic areas hV4, VO-1/2, and hMT+. Furthermore, these activations show a gradient of increasing face selectivity and decreasing limb selectivity from the IOG to the mFus. Finally, MVP analyses indicate that there is differential information for faces in lateral VTC (containing weakly- and highly-selective voxels) relative to non-selective voxels in medial VTC. These findings suggest a sparsely-distributed organization where sparseness refers to the presence of several face- and limb-selective clusters in VTC, and distributed refers to the presence of different amounts of information in highly-, weakly-, and non-selective voxels. Consequently, theories of object recognition should consider the functional and spatial constraints of neural coding across a series of minimally overlapping category-selective clusters that are themselves distributed.

  View details for DOI 10.1016/j.neuroimage.2010.04.262

  View details for Web of Science ID 000280695200044

  View details for PubMedID 20457261

  View details for PubMedCentralID PMC3122128

• fMRI-Adaptation and Category Selectivity in Human Ventral Temporal Cortex: Regional Differences Across Time Scales JOURNAL OF NEUROPHYSIOLOGY Weiner, K. S., Sayres, R., Vinberg, J., Grill-Spector, K. 2010; 103 (6): 3349-3365

  Abstract

  Repeating object images produces stimulus-specific repetition suppression referred to as functional magnetic resonance imaging-adaptation (fMRI-A) in ventral temporal cortex (VTC). However, the effects of stimulus repetition on functional selectivity are largely unknown. We investigated the effects of short-lagged (SL, immediate) and long-lagged (LL, many intervening stimuli) repetitions on category selectivity in VTC using high-resolution fMRI. We asked whether repetition produces scaling or sharpening of fMRI responses both within category-selective regions as well as in the distributed response pattern across VTC. Results illustrate that repetition effects across time scales vary quantitatively along an anterior-posterior axis and qualitatively along a lateral-medial axis. In lateral VTC, both SL and LL repetitions produce proportional fMRI-A with no change in either selectivity or distributed responses as predicted by a scaling model. Further, there is larger fMRI-A in anterior subregions irrespective of category selectivity. Medial VTC exhibits similar scaling effects during SL repetitions. However, for LL repetitions, both the selectivity and distributed pattern of responses vary with category in medial VTC as predicted by a sharpening model. Specifically, there is larger fMRI-A for nonpreferred categories compared with the preferred category, and category selectivity does not predict fMRI-A across the pattern of distributed response. Finally, simulations indicate that different neural mechanisms likely underlie fMRI-A in medial compared to lateral VTC. These results have important implications for future fMRI-A experiments because they suggest that fMRI-A does not reflect a universal neural mechanism and that results of fMRI-A experiments will likely be paradigm independent in lateral VTC but paradigm dependent in medial VTC.

  View details for DOI 10.1152/jn.01108.2009

  View details for Web of Science ID 000278493900035

  View details for PubMedID 20375251

  View details for PubMedCentralID PMC2888251

• The Fusiform Face Area is Enlarged in Williams Syndrome JOURNAL OF NEUROSCIENCE Golarai, G., Hong, S., Haas, B. W., Galaburda, A. M., Mills, D. L., Bellugi, U., Grill-Spector, K., Reiss, A. L. 2010; 30 (19): 6700-6712

  Abstract

  Williams syndrome (WS) is a genetic condition characterized by atypical brain structure, cognitive deficits, and a life-long fascination with faces. Face recognition is relatively spared in WS, despite abnormalities in aspects of face processing and structural alterations in the fusiform gyrus, part of the ventral visual stream. Thus, face recognition in WS may be subserved by abnormal neural substrates in the ventral stream. To test this hypothesis, we used functional magnetic resonance imaging and examined the fusiform face area (FFA), which is implicated in face recognition in typically developed (TD) individuals, but its role in WS is not well understood. We found that the FFA was approximately two times larger among WS than TD participants (both absolutely and relative to the fusiform gyrus), despite apparently normal levels of face recognition performance on a Benton face recognition test. Thus, a larger FFA may play a role in face recognition proficiency among WS.

  View details for DOI 10.1523/JNEUROSCI.4268-09.2010

  View details for Web of Science ID 000277653600023

  View details for PubMedID 20463232

  View details for PubMedCentralID PMC3670816

• Controlling stimulus variability reveals stronger face-selective responses near the average face 17th Annual Meeting on Object Perception, Attention and Memory Davidenko, N., Grill-Spector, K. PSYCHOLOGY PRESS. 2010: 122–26

  View details for Web of Science ID 000274036200010

• Differential development of the ventral visual cortex extends through adolescence. Frontiers in human neuroscience Golarai, G., Liberman, A., Yoon, J. M., Grill-Spector, K. 2010; 3: 80-?

  Abstract

  The ventral temporal cortex (VTC) in humans includes functionally defined regions that preferentially respond to objects, faces, and places. Recent developmental studies suggest that the face selective region in the fusiform gyrus ('fusiform face area', FFA) undergoes a prolonged development involving substantial increases in its volume after 7 years of age. However, the endpoint of this development is not known. Here we used functional magnetic resonance imaging (fMRI) to examine the development of face-, object- and place selective regions in the VTC of adolescents (12-16 year olds) and adults (18-40 year olds). We found that the volume of face selective activations in the right fusiform gyrus was substantially larger in adults than in adolescents, and was positively correlated with age. This development was associated with higher response amplitudes and selectivity for faces in face selective regions of VTC and increased differentiation of the distributed response patterns to faces versus non-face stimuli across the entire VTC. Furthermore, right FFA size was positively correlated with face recognition memory performance, but not with recognition memory of objects or places. In contrast, the volume of object- and place selective cortical regions or their response amplitudes did not change across these age groups. Thus, we found a striking and prolonged development of face selectivity across the VTC during adolescence that was specifically associated with proficiency in face recognition memory. These findings have important implications for theories of development and functional specialization in VTC.

  View details for DOI 10.3389/neuro.09.080.2009

  View details for PubMedID 20204140

  View details for PubMedCentralID PMC2831628

• Deos the Bairn Not Raed Ervey Lteter by Istlef, but the Wrod as a Wlohe? NEURON Grill-Spector, K., Witthoft, N. 2009; 62 (2): 161-162

  Abstract

  In this issue of Neuron, Glezer et al. find higher sensitivity to changes in real words than pseudowords in the left visual word form area (VWFA). Here we discuss the implications of their findings and the constraints they impose on neural coding in the lVWFA.

  View details for DOI 10.1016/j.neuron.2009.04.009

  View details for Web of Science ID 000265774100002

  View details for PubMedID 19409259

• The representation of object viewpoint in human visual cortex NEUROIMAGE Andresen, D. R., Vinberg, J., Grill-Spector, K. 2009; 45 (2): 522-536

  Abstract

  Understanding the nature of object representations in the human brain is critical for understanding the neural basis of invariant object recognition. However, the degree to which object representations are sensitive to object viewpoint is unknown. Using fMRI we employed a parametric approach to examine the sensitivity to object view as a function of rotation (0 degrees-180 degrees ), category (animal/vehicle) and fMRI-adaptation paradigm (short or long-lagged). For both categories and fMRI-adaptation paradigms, object-selective regions recovered from adaptation when a rotated view of an object was shown after adaptation to a specific view of that object, suggesting that representations are sensitive to object rotation. However, we found evidence for differential representations across categories and ventral stream regions. Rotation cross-adaptation was larger for animals than vehicles, suggesting higher sensitivity to vehicle than animal rotation, and was largest in the left fusiform/occipito-temporal sulcus (pFUS/OTS), suggesting that this region has low sensitivity to rotation. Moreover, right pFUS/OTS and FFA responded more strongly to front than back views of animals (without adaptation) and rotation cross-adaptation depended both on the level of rotation and the adapting view. This result suggests a prevalence of neurons that prefer frontal views of animals in fusiform regions. Using a computational model of view-tuned neurons, we demonstrate that differential neural view tuning widths and relative distributions of neural-tuned populations in fMRI voxels can explain the fMRI results. Overall, our findings underscore the utility of parametric approaches for studying the neural basis of object invariance and suggest that there is no complete invariance to object view in the human ventral stream.

  View details for DOI 10.1016/j.neuroimage.2008.11.009

  View details for Web of Science ID 000263863000031

  View details for PubMedID 19100844

• Fine-Scale Spatial Organization of Face and Object Selectivity in the Temporal Lobe: Do Functional Magnetic Resonance Imaging, Optical Imaging, and Electrophysiology Agree? JOURNAL OF NEUROSCIENCE Op de Beeck, H. P., DiCarlo, J. J., Goense, J. B., Grill-Spector, K., Papanastassiou, A., Tanifuji, M., Tsao, D. Y. 2008; 28 (46): 11796-11801

  Abstract

  The spatial organization of the brain's object and face representations in the temporal lobe is critical for understanding high-level vision and cognition but is poorly understood. Recently, exciting progress has been made using advanced imaging and physiology methods in humans and nonhuman primates, and the combination of such methods may be particularly powerful. Studies applying these methods help us to understand how neuronal activity, optical imaging, and functional magnetic resonance imaging signals are related within the temporal lobe, and to uncover the fine-grained and large-scale spatial organization of object and face representations in the primate brain.

  View details for DOI 10.1523/JNEUROSCI.3799-08.2008

  View details for Web of Science ID 000260827600009

  View details for PubMedID 19005042

• Relating retinotopic and object-selective responses in human lateral occipital cortex JOURNAL OF NEUROPHYSIOLOGY Sayres, R., Grill-Spector, K. 2008; 100 (1): 249-267

  Abstract

  What is the relationship between retinotopy and object selectivity in human lateral occipital (LO) cortex? We used functional magnetic resonance imaging (fMRI) to examine sensitivity to retinal position and category in LO, an object-selective region positioned posterior to MT along the lateral cortical surface. Six subjects participated in phase-encoded retinotopic mapping experiments as well as block-design experiments in which objects from six different categories were presented at six distinct positions in the visual field. We found substantial position modulation in LO using standard nonobject retinotopic mapping stimuli; this modulation extended beyond the boundaries of visual field maps LO-1 and LO-2. Further, LO showed a pronounced lower visual field bias: more LO voxels represented the lower contralateral visual field, and the mean LO response was higher to objects presented below fixation than above fixation. However, eccentricity effects produced by retinotopic mapping stimuli and objects differed. Whereas LO voxels preferred a range of eccentricities lying mostly outside the fovea in the retinotopic mapping experiment, LO responses were strongest to foveally presented objects. Finally, we found a stronger effect of position than category on both the mean LO response, as well as the distributed response across voxels. Overall these results demonstrate that retinal position exhibits strong effects on neural response in LO and indicates that these position effects may be explained by retinotopic organization.

  View details for DOI 10.1152/jn.01383.2007

  View details for Web of Science ID 000257635400023

  View details for PubMedID 18463186

  View details for PubMedCentralID PMC2493478

• Developmental neuroimaging of the human ventral visual cortex TRENDS IN COGNITIVE SCIENCES Grill-Spector, K., Golarai, G., Gabrieli, J. 2008; 12 (4): 152-162

  Abstract

  Here, we review recent results that investigate the development of the human ventral stream from childhood, through adolescence and into adulthood. Converging evidence suggests a differential developmental trajectory across ventral stream regions, in which face-selective regions show a particularly long developmental time course, taking more than a decade to become adult-like. We discuss the implications of these recent findings, how they relate to age-dependent improvements in recognition memory performance and propose possible neural mechanisms that might underlie this development. These results have important implications regarding the role of experience in shaping the ventral stream and the nature of the underlying representations.

  View details for Web of Science ID 000255469200008

  View details for PubMedID 18359267

• Object recognition: Insights from advances in fMRI methods CURRENT DIRECTIONS IN PSYCHOLOGICAL SCIENCE Grill-Spector, K., Sayres, R. 2008; 17 (2): 73-79

  View details for Web of Science ID 000254807700004

• Representation of shapes, edges, and surfaces across multiple cues in the human visual cortex JOURNAL OF NEUROPHYSIOLOGY Vinberg, J., Grill-Spector, K. 2008; 99 (3): 1380-1393

  Abstract

  The lateral occipital complex (LOC) responds preferentially to objects compared with random stimuli or textures independent of the visual cue. However, it is unknown whether the LOC (or other cortical regions) are involved in the processing of edges or global surfaces without shape information. Here, we examined processing of 1) global shape, 2) disconnected edges without a global shape, and 3) global surfaces without edges versus random stimuli across motion and stereo cues. The LOC responded more strongly to global shapes than to edges, surfaces, or random stimuli, for both motion and stereo cues. However, its responses to local edges or global surfaces were not different from random stimuli. This suggests that the LOC processes shapes, not edges or surfaces. LOC also responded more strongly to objects than to holes with the same shape, suggesting sensitivity to border ownership. V7 responded more strongly to edges than to surfaces or random stimuli for both motion and stereo cues, whereas V3a and V4 preferred motion edges. Finally, a region in the caudal intraparietal sulcus (cIPS) responded more strongly to both stereo versus motion and to stereo surfaces versus random stereo (but not to motion surfaces vs. random motion). Thus we found evidence for cue-specific responses to surfaces in the cIPS, both cue-specific and cue-independent responses to edges in intermediate visual areas, and shape-selective responses across multiple cues in the LOC. Overall, these data suggest that integration of visual information across multiple cues is mainly achieved at the level of shape and underscore LOC's role in shape computations.

  View details for DOI 10.1152/jn.01223.2007

  View details for Web of Science ID 000253969300030

  View details for PubMedID 18171705

• Differential development of high-level visual cortex correlates with category-specific recognition memory NATURE NEUROSCIENCE Golarai, G., Ghahremani, D. G., Whitfield-Gabrieli, S., Reiss, A., Eberhardt, J. L., Gabrieli, J. D., Grill-Spector, K. 2007; 10 (4): 512-522

  Abstract

  High-level visual cortex in humans includes functionally defined regions that preferentially respond to objects, faces and places. It is unknown how these regions develop and whether their development relates to recognition memory. We used functional magnetic resonance imaging to examine the development of several functionally defined regions including object (lateral occipital complex, LOC)-, face ('fusiform face area', FFA; superior temporal sulcus, STS)- and place ('parahippocampal place area', PPA)-selective cortices in children (ages 7-11), adolescents (12-16) and adults. Right FFA and left PPA volumes were substantially larger in adults than in children. This development occurred by expansion of FFA and PPA into surrounding cortex and was correlated with improved recognition memory for faces and places, respectively. In contrast, LOC and STS volumes and object-recognition memory remained constant across ages. Thus, the ventral stream undergoes a prolonged maturation that varies temporally across functional regions, is determined by brain region rather than stimulus category, and is correlated with the development of category-specific recognition memory.

  View details for DOI 10.1038/nn1865

  View details for Web of Science ID 000245228600023

  View details for PubMedID 17351637

  View details for PubMedCentralID PMC3660101

• Autism and the development of face processing. Clinical neuroscience research Golarai, G., Grill-Spector, K., Reiss, A. L. 2006; 6 (3): 145-160

  Abstract

  Autism is a pervasive developmental condition, characterized by impairments in non-verbal communication, social relationships and stereotypical patterns of behavior. A large body of evidence suggests that several aspects of face processing are impaired in autism, including anomalies in gaze processing, memory for facial identity and recognition of facial expressions of emotion. In search of neural markers of anomalous face processing in autism, much interest has focused on a network of brain regions that are implicated in social cognition and face processing. In this review, we will focus on three such regions, namely the STS for its role in processing gaze and facial movements, the FFA in face detection and identification and the amygdala in processing facial expressions of emotion. Much evidence suggests that a better understanding of the normal development of these specialized regions is essential for discovering the neural bases of face processing anomalies in autism. Thus, we will also examine the available literature on the normal development of face processing. Key unknowns in this research area are the neuro-developmental processes, the role of experience and the interactions among components of the face processing system in shaping each of the specialized regions for processing faces during normal development and in autism.

  View details for PubMedID 18176635

• Autism and the development of face processing 85th Annual Conference of the Association-for-Reseach-in-Nervous-and-Mental-Disease Golarai, G., Grill-Spector, K., Reiss, A. L. ELSEVIER SCI LTD. 2006: 145–60

  Abstract

  Autism is a pervasive developmental condition, characterized by impairments in non-verbal communication, social relationships and stereotypical patterns of behavior. A large body of evidence suggests that several aspects of face processing are impaired in autism, including anomalies in gaze processing, memory for facial identity and recognition of facial expressions of emotion. In search of neural markers of anomalous face processing in autism, much interest has focused on a network of brain regions that are implicated in social cognition and face processing. In this review, we will focus on three such regions, namely the STS for its role in processing gaze and facial movements, the FFA in face detection and identification and the amygdala in processing facial expressions of emotion. Much evidence suggests that a better understanding of the normal development of these specialized regions is essential for discovering the neural bases of face processing anomalies in autism. Thus, we will also examine the available literature on the normal development of face processing. Key unknowns in this research area are the neuro-developmental processes, the role of experience and the interactions among components of the face processing system in shaping each of the specialized regions for processing faces during normal development and in autism.

  View details for DOI 10.1016/j.cnr.2006.08.001

  View details for Web of Science ID 000242486200006

  View details for PubMedCentralID PMC2174902

• High-resolution imaging reveals highly selective nonface clusters in the fusiform face area NATURE NEUROSCIENCE Grill-Spector, K., Sayres, R., Ress, D. 2006; 9 (9): 1177-1185

  Abstract

  A region in ventral human cortex (fusiform face area, FFA) thought to be important for face perception responds strongly to faces and less strongly to nonface objects. This pattern of response may reflect a uniform face-selective neural population or activity averaged across populations with heterogeneous selectivity. Using high-resolution functional magnetic resonance imaging (MRI), we found that the FFA has a reliable heterogeneous structure: localized subregions within the FFA highly selective to faces are spatially interdigitated with localized subregions highly selective to different object categories. We found a preponderance of face-selective responses in the FFA, but no difference in selectivity to faces compared to nonfaces. Thus, standard fMRI of the FFA reflects averaging of heterogeneous highly selective neural populations of differing sizes, rather than higher selectivity to faces. These results suggest that visual processing in this region is not exclusive to faces. Overall, our approach provides a framework for understanding the fine-scale structure of neural representations in the human brain.

  View details for DOI 10.1038/nn1745

  View details for Web of Science ID 000240080800020

  View details for PubMedID 16892057

• Object-selective cortex exhibits performance-independent repetition suppression JOURNAL OF NEUROPHYSIOLOGY Sayres, R., Grill-Spector, K. 2006; 95 (2): 995-1007

  Abstract

  Object-selective cortical regions exhibit a decreased response when an object stimulus is repeated [repetition suppression (RS)]. RS is often associated with priming: reduced response times and increased accuracy for repeated stimuli. It is unknown whether RS reflects stimulus-specific repetition, the associated changes in response time, or the combination of the two. To address this question, we performed a rapid event-related functional MRI (fMRI) study in which we measured BOLD signal in object-selective cortex, as well as object recognition performance, while we manipulated stimulus repetition. Our design allowed us to examine separately the roles of response time and repetition in explaining RS. We found that repetition played a robust role in explaining RS: repeated trials produced weaker BOLD responses than nonrepeated trials, even when comparing trials with matched response times. In contrast, response time played a weak role in explaining RS when repetition was controlled for: it explained BOLD responses only for one region of interest (ROI) and one experimental condition. Thus repetition suppression seems to be mostly driven by repetition rather than performance changes. We further examined whether RS reflects processes occurring at the same time as recognition or after recognition by manipulating stimulus presentation duration. In one experiment, durations were longer than required for recognition (2 s), whereas in a second experiment, durations were close to the minimum time required for recognition (85-101 ms). We found significant RS for brief presentations (albeit with a reduced magnitude), which again persisted when controlling for performance. This suggests a substantial amount of RS occurs during recognition.

  View details for DOI 10.1152/jn.00500.2005

  View details for Web of Science ID 000234759600040

  View details for PubMedID 16236787

• Selectivity of adaptation in single units: Implications for fMRI experiments NEURON Grill-Spector, K. 2006; 49 (2): 170-171

  Abstract

  Understanding the neural basis of adaptation (repetition suppression) is critical for interpreting fMRI-adaptation experiments. Sawamura and colleagues provide a critical stepping-stone by elucidating the relation between neural adaptation and response selectivity. They find some cross-adaptation by two different stimuli that activate the same neuron.

  View details for DOI 10.1016/j.neuron.2006.01.004

  View details for Web of Science ID 000234979900003

  View details for PubMedID 16423690

• Repetition and the brain: neural models of stimulus-specific effects TRENDS IN COGNITIVE SCIENCES Grill-Spector, K., Henson, R., Martin, A. 2006; 10 (1): 14-23

  Abstract

  One of the most robust experience-related cortical dynamics is reduced neural activity when stimuli are repeated. This reduction has been linked to performance improvements due to repetition and also used to probe functional characteristics of neural populations. However, the underlying neural mechanisms are as yet unknown. Here, we consider three models that have been proposed to account for repetition-related reductions in neural activity, and evaluate them in terms of their ability to account for the main properties of this phenomenon as measured with single-cell recordings and neuroimaging techniques. We also discuss future directions for distinguishing between these models, which will be important for understanding the neural consequences of repetition and for interpreting repetition-related effects in neuroimaging data.

  View details for DOI 10.1016/j.tics.2005.11.006

  View details for Web of Science ID 000234910400007

  View details for PubMedID 16321563

• Visual recognition - As soon as you know it is there, you know what it is PSYCHOLOGICAL SCIENCE Grill-Spector, K., Kanwisher, N. 2005; 16 (2): 152-160

  Abstract

  What is the sequence of processing steps involved in visual object recognition? We varied the exposure duration of natural images and measured subjects' performance on three different tasks, each designed to tap a different candidate component process of object recognition. For each exposure duration, accuracy was lower and reaction time longer on a within-category identification task (e.g., distinguishing pigeons from other birds) than on a perceptual categorization task (e.g., birds vs. cars). However, strikingly, at each exposure duration, subjects performed just as quickly and accurately on the categorization task as they did on a task requiring only object detection: By the time subjects knew an image contained an object at all, they already knew its category. These findings place powerful constraints on theories of object recognition.

  View details for Web of Science ID 000226656000011

  View details for PubMedID 15686582

• The fusiform face area subserves face perception, not generic within-category identification NATURE NEUROSCIENCE Grill-Spector, K., Knouf, N., Kanwisher, N. 2004; 7 (5): 555-562

  Abstract

  The function of the fusiform face area (FFA), a face-selective region in human extrastriate cortex, is a matter of active debate. Here we measured the correlation between FFA activity measured by functional magnetic resonance imaging (fMRI) and behavioral outcomes in perceptual tasks to determine the role of the FFA in the detection and within-category identification of faces and objects. Our data show that FFA activation is correlated on a trial-by-trial basis with both detecting the presence of faces and identifying specific faces. However, for most non-face objects (including cars seen by car experts), within-category identification performance was correlated with activation in other regions of the ventral occipitotemporal cortex, not the FFA. These results indicate that the FFA is involved in both detection and identification of faces, but that it has little involvement in within-category identification of non-face objects (including objects of expertise).

  View details for DOI 10.1038/nn1224

  View details for Web of Science ID 000221101300034

  View details for PubMedID 15077112

• The human visual cortex ANNUAL REVIEW OF NEUROSCIENCE Grill-Spector, K., Malach, R. 2004; 27: 649-677

  Abstract

  The discovery and analysis of cortical visual areas is a major accomplishment of visual neuroscience. In the past decade the use of noninvasive functional imaging, particularly functional magnetic resonance imaging (fMRI), has dramatically increased our detailed knowledge of the functional organization of the human visual cortex and its relation to visual perception. The fMRI method offers a major advantage over other techniques applied in neuroscience by providing a large-scale neuroanatomical perspective that stems from its ability to image the entire brain essentially at once. This bird's eye view has the potential to reveal large-scale principles within the very complex plethora of visual areas. Thus, it could arrange the entire constellation of human visual areas in a unified functional organizational framework. Here we review recent findings and methods employed to uncover the functional properties of the human visual cortex focusing on two themes: functional specialization and hierarchical processing.

  View details for DOI 10.1146/annurev.neuro.27.070203.144220

  View details for Web of Science ID 000223246300023

  View details for PubMedID 15217346

• The neural basis of object perception CURRENT OPINION IN NEUROBIOLOGY Grill-Spector, K. 2003; 13 (2): 159-166

  Abstract

  Humans can recognize an object within a fraction of a second, even if there are no clues about what kind of object it might be. Recent findings have identified functional properties of extrastriate regions in the ventral visual pathway that are involved in the representation and perception of objects and faces. The functional properties of these regions, and the correlation between the activation of these regions and visual recognition, indicate that the lateral and ventral occipito-temporal areas are important in perceiving and recognizing objects and faces.

  View details for DOI 10.1016/S0959-4388(03)00040-0

  View details for Web of Science ID 000183092700004

  View details for PubMedID 12744968

• fMR-adaptation: a tool for studying the functional properties of human cortical neurons ACTA PSYCHOLOGICA Grill-Spector, K., Malach, R. 2001; 107 (1-3): 293-321

  Abstract

  The invariant properties of human cortical neurons cannot be studied directly by fMRI due to its limited spatial resolution. One voxel obtained from a fMRI scan contains several hundred thousands neurons. Therefore, the fMRI signal may average out a heterogeneous group of highly selective neurons. Here, we present a novel experimental paradigm for fMRI, functional magnetic resonance-adaptation (fMR-A), that enables to tag specific neuronal populations within an area and investigate their functional properties. This approach contrasts with conventional mapping methods that measure the averaged activity of a region. The application of fMR-A to study the functional properties of cortical neurons proceeds in two stages: First, the neuronal population is adapted by repeated presentation of a single stimulus. Second, some property of the stimulus is varied and the recovery from adaptation is assessed. If the signal remains adapted, it will indicate that the neurons are invariant to that attribute. However, if the fMRI signal will recover from the adapted state it would imply that the neurons are sensitive to the property that was varied. Here, an application of fMR-A for studying the invariant properties of high-order object areas (lateral occipital complex--LOC) to changes in object size, position, illumination and rotation is presented. The results show that LOC is less sensitive to changes in object size and position compared to changes of illumination and viewpoint. fMR-A can be extended to other neuronal systems in which adaptation is manifested and can be used with event-related paradigms as well. By manipulating experimental parameters and testing recovery from adaptation it should be possible to gain insight into the functional properties of cortical neurons which are beyond the spatial resolution limits imposed by conventional fMRI.

  View details for Web of Science ID 000168792700013

  View details for PubMedID 11388140

• The lateral occipital complex and its role in object recognition VISION RESEARCH Grill-Spector, K., Kourtzi, Z., Kanwisher, N. 2001; 41 (10-11): 1409-1422

  Abstract

  Here we review recent findings that reveal the functional properties of extra-striate regions in the human visual cortex that are involved in the representation and perception of objects. We characterize both the invariant and non-invariant properties of these regions and we discuss the correlation between activation of these regions and recognition. Overall, these results indicate that the lateral occipital complex plays an important role in human object recognition.

  View details for Web of Science ID 000168565200016

  View details for PubMedID 11322983

• The dynamics of object-selective activation correlate with recognition performance in humans NATURE NEUROSCIENCE Grill-Spector, K., Kushnir, T., Hendler, T., Malach, R. 2000; 3 (8): 837-843

  Abstract

  To investigate the relationship between perceptual awareness and brain activity, we measured both recognition performance and fMRI signal from object-related areas in human cortex while images were presented briefly using a masking protocol. Our results suggest that recognition performance is correlated with selective activation in object areas. Selective activation was correlated to object naming when exposure duration was varied from 20 to 500 milliseconds. Subjects' recognition during identical visual stimulation could be enhanced by training, which also increased the fMRI signal. Overall, the correlation between recognition performance and fMRI signal was highest in occipitotemporal object areas (the lateral occipital complex).

  View details for Web of Science ID 000167177300021

  View details for PubMedID 10903579

• Differential processing of objects under various viewing conditions in the human lateral occipital complex NEURON Grill-Spector, K., Kushnir, T., Edelman, S., Avidan, G., Itzchak, Y., Malach, R. 1999; 24 (1): 187-203

  Abstract

  The invariant properties of human cortical neurons cannot be studied directly by fMRI due to its limited spatial resolution. Here, we circumvented this limitation by using fMR adaptation, namely, reduction of the fMR signal due to repeated presentation of identical images. Object-selective regions (lateral occipital complex [LOC]) showed a monotonic signal decrease as repetition frequency increased. The invariant properties of fMR adaptation were studied by presenting the same object in different viewing conditions. LOC exhibited stronger fMR adaptation to changes in size and position (more invariance) compared to illumination and viewpoint. The effect revealed two putative subdivisions within LOC: caudal-dorsal (LO), which exhibited substantial recovery from adaptation under all transformations, and posterior fusiform (PF/LOa), which displayed stronger adaptation. This study demonstrates the utility of fMR adaptation for revealing functional characteristics of neurons in fMRI studies.

  View details for Web of Science ID 000082893200019

  View details for PubMedID 10677037

• Toward direct visualization of the internal shape representation space by fMRI PSYCHOBIOLOGY Edelman, S., Grill-Spector, K., Kushnir, T., Malach, R. 1998; 26 (4): 309-321

  View details for Web of Science ID 000078391900003

• Cue-invariant activation in object-related areas of the human occipital lobe NEURON Grill-Spector, K., Kushnir, T., Edelman, S., Itzchak, Y., Malach, R. 1998; 21 (1): 191-202

  Abstract

  The extent to which primary visual cues such as motion or luminance are segregated in different cortical areas is a subject of controversy. To address this issue, we examined cortical activation in the human occipital lobe using functional magnetic resonance imaging (fMRI) while subjects performed a fixed visual task, object recognition, using three different primary visual cues: motion, texture, or luminance contrast. In the first experiment, a region located on the lateral aspect of the occipital lobe (LO complex) was preferentially activated in all 11 subjects both by luminance and motion-defined object silhouettes compared to full-field moving and stationary noise (ratios, 2.00+/-0.19 and 1.86+/-0.65, respectively). In the second experiment, all subjects showed enhanced activation in the LO complex to objects defined both by luminance and texture contrast compared to full-field texture patterns (ratios, 1.43+/-0.08 and 1.32+/-0.08, respectively). An additional smaller dorsal focus that exhibited convergence of object-related cues appeared to correspond to area V3a or a region slightly anterior to it. These results show convergence of visual cues in LO and provide strong evidence for its role in object processing.

  View details for Web of Science ID 000075061900018

  View details for PubMedID 9697863

• A sequence of object-processing stages revealed by fMRI in the human occipital lobe HUMAN BRAIN MAPPING Grill-Spector, K., Kushnir, T., Hendler, T., Edelman, S., Itzchak, Y., Malach, R. 1998; 6 (4): 316-328

  Abstract

  Functional magnetic resonance imaging was used in combined functional selectivity and retinotopic mapping tests to reveal object-related visual areas in the human occipital lobe. Subjects were tested with right, left, up, or down hemivisual field stimuli which were composed of images of natural objects (faces, animals, man-made objects) or highly scrambled (1,024 elements) versions of the same images. In a similar fashion, the horizontal and vertical meridians were mapped to define the borders of these areas. Concurrently, the same cortical sites were tested for their sensitivity to image-scrambling by varying the number of scrambled picture fragments (from 16-1,024) while controlling for the Fourier power spectrum of the pictures and their order of presentation. Our results reveal a stagewise decrease in retinotopy and an increase in sensitivity to image-scrambling. Three main distinct foci were found in the human visual object recognition pathway (Ungerleider and Haxby [1994]: Curr Opin Neurobiol 4:157-165): 1) Retinotopic primary areas V1-3 did not exhibit significant reduction in activation to scrambled images. 2) Areas V4v (Sereno et al., [1995]: Science 268:889-893) and V3A (De Yoe et al., [1996]: Proc Natl Acad Sci USA 93:2382-2386; Tootell et al., [1997]: J Neurosci 71:7060-7078) manifested both retinotopy and decreased activation to highly scrambled images. 3) The essentially nonretinotopic lateral occipital complex (LO) (Malach et al., [1995]: Proc Natl Acad Sci USA 92:8135-8139; Tootell et al., [1996]: Trends Neurosci 19:481-489) exhibited the highest sensitivity to image scrambling, and appears to be homologous to macaque the infero-temporal (IT) cortex (Tanaka [1996]: Curr Opin Neurobiol 523-529). Breaking the images into 64, 256, or 1,024 randomly scrambled blocks reduced activation in LO voxels. However, many LO voxels remained significantly activated by mildly scrambled images (16 blocks). These results suggest the existence of object-fragment representation in LO.

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  View details for PubMedID 9704268