Bio


Dr. Jason Yeatman is an Assistant Professor in the Graduate School of Education and Division of Developmental and Behavioral Pediatrics at Stanford University. Dr. Yeatman completed his PhD in Psychology at Stanford where he studied the neurobiology of literacy and developed new brain imaging methods for studying the relationship between brain plasticity and learning. After finishing his PhD, he took a faculty position at the University of Washington’s Institute for Learning and Brain Sciences before returning to Stanford.

As the director of the Brain Development and Education Lab, the overarching goal of his research is to understand the mechanisms that underlie the process of learning to read, how these mechanisms differ in children with dyslexia, and to design literacy intervention programs that are effective across the wide spectrum of learning differences. His lab employs a collection of structural and functional neuroimaging measurements to study how a child’s experience with reading instruction shapes the development of brain circuits that are specialized for this unique cognitive function.

Academic Appointments


Research Interests


  • Brain and Learning Sciences
  • Child Development
  • Data Sciences
  • Early Childhood
  • Literacy and Language
  • Psychology
  • Research Methods
  • Special Education
  • Technology and Education

2019-20 Courses


Stanford Advisees


All Publications


  • Evaluating arcuate fasciculus laterality measurements across dataset and tractography pipelines HUMAN BRAIN MAPPING Bain, J. S., Yeatman, J. D., Schurr, R., Rokem, A., Mezer, A. A. 2019; 40 (13): 3695–3711

    Abstract

    The arcuate fasciculi are white-matter pathways that connect frontal and temporal lobes in each hemisphere. The arcuate plays a key role in the language network and is believed to be left-lateralized, in line with left hemisphere dominance for language. Measuring the arcuate in vivo requires diffusion magnetic resonance imaging-based tractography, but asymmetry of the in vivo arcuate is not always reliably detected in previous studies. It is unknown how the choice of tractography algorithm, with each method's freedoms, constraints, and vulnerabilities to false-positive and -negative errors, impacts findings of arcuate asymmetry. Here, we identify the arcuate in two independent datasets using a number of tractography strategies and methodological constraints, and assess their impact on estimates of arcuate laterality. We test three tractography methods: a deterministic, a probabilistic, and a tractography-evaluation (LiFE) algorithm. We extract the arcuate from the whole-brain tractogram, and compare it to an arcuate bundle constrained even further by selecting only those streamlines that connect to anatomically relevant cortical regions. We test arcuate macrostructure laterality, and also evaluate microstructure profiles for properties such as fractional anisotropy and quantitative R1. We find that both tractography choice and implementing the cortical constraints substantially impact estimates of all indices of arcuate laterality. Together, these results emphasize the effect of the tractography pipeline on estimates of arcuate laterality in both macrostructure and microstructure.

    View details for DOI 10.1002/hbm.24626

    View details for Web of Science ID 000478645900001

    View details for PubMedID 31106944

    View details for PubMedCentralID PMC6679767

  • The link between reading ability and visual spatial attention across development. Cortex; a journal devoted to the study of the nervous system and behavior White, A. L., Boynton, G. M., Yeatman, J. D. 2019; 121: 44–59

    Abstract

    Interacting with a cluttered and dynamic environment requires making decisions about visual information at relevant locations while ignoring irrelevant locations. Typical adults can do this with covert spatial attention: prioritizing particular visual field locations even without moving the eyes. Deficits of covert spatial attention have been implicated in developmental dyslexia, a specific reading disability. Previous studies of children with dyslexia, however, have been complicated by group differences in overall task ability that are difficult to distinguish from selective spatial attention. Here, we used a single-fixation visual search task to estimate orientation discrimination thresholds with and without an informative spatial cue in a large sample (N=123) of people ranging in age from 5 to 70 years and with a wide range of reading abilities. We assessed the efficiency of attentional selection via the cueing effect: the difference in log thresholds with and without the spatial cue. Across our whole sample, both absolute thresholds and the cueing effect gradually improved throughout childhood and adolescence. Compared to typical readers, individuals with dyslexia had higher thresholds (worse orientation discrimination) as well as smaller cueing effects (weaker attentional selection). Those differences in dyslexia were especially pronounced prior to age 20, when basic visual function is still maturing. Thus, in line with previous theories, literacy skills are associated with the development of selective spatial attention.

    View details for DOI 10.1016/j.cortex.2019.08.011

    View details for PubMedID 31542467

  • Intensive Summer Intervention Drives Linear Growth of Reading Skill in Struggling Readers FRONTIERS IN PSYCHOLOGY Donnelly, P. M., Huber, E., Yeatman, J. D. 2019; 10
  • You Can't Recognize Two Words Simultaneously. Trends in cognitive sciences White, A. L., Boynton, G. M., Yeatman, J. D. 2019

    View details for DOI 10.1016/j.tics.2019.07.001

    View details for PubMedID 31477387

  • Categorical phoneme labeling in children with dyslexia does not depend on stimulus duration JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA O'Brien, G. E., McCloy, D. R., Yeatman, J. D. 2019; 146 (1): 245–55

    Abstract

    It is established that individuals with dyslexia are less consistent at auditory phoneme categorization than typical readers. One hypothesis attributes these differences in phoneme labeling to differences in auditory cue integration over time, suggesting that the performance of individuals with dyslexia would improve with longer exposure to informative phonetic cues. Here, the relationship between phoneme labeling and reading ability was investigated while manipulating the duration of steady-state auditory information available in a consonant-vowel syllable. Children with dyslexia obtained no more benefit from longer cues than did children with typical reading skills, suggesting that poor task performance is not explained by deficits in temporal integration or temporal sampling.

    View details for DOI 10.1121/1.5116568

    View details for Web of Science ID 000478628800037

    View details for PubMedID 31370631

    View details for PubMedCentralID PMC6639114

  • Parallel spatial channels converge at a bottleneck in anterior word-selective cortex PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA White, A. L., Palmer, J., Boynton, G. M., Yeatman, J. D. 2019; 116 (20): 10087–96

    Abstract

    In most environments, the visual system is confronted with many relevant objects simultaneously. That is especially true during reading. However, behavioral data demonstrate that a serial bottleneck prevents recognition of more than one word at a time. We used fMRI to investigate how parallel spatial channels of visual processing converge into a serial bottleneck for word recognition. Participants viewed pairs of words presented simultaneously. We found that retinotopic cortex processed the two words in parallel spatial channels, one in each contralateral hemisphere. Responses were higher for attended than for ignored words but were not reduced when attention was divided. We then analyzed two word-selective regions along the occipitotemporal sulcus (OTS) of both hemispheres (subregions of the visual word form area, VWFA). Unlike retinotopic regions, each word-selective region responded to words on both sides of fixation. Nonetheless, a single region in the left hemisphere (posterior OTS) contained spatial channels for both hemifields that were independently modulated by selective attention. Thus, the left posterior VWFA supports parallel processing of multiple words. In contrast, activity in a more anterior word-selective region in the left hemisphere (mid OTS) was consistent with a single channel, showing (i) limited spatial selectivity, (ii) no effect of spatial attention on mean response amplitudes, and (iii) sensitivity to lexical properties of only one attended word. Therefore, the visual system can process two words in parallel up to a late stage in the ventral stream. The transition to a single channel is consistent with the observed bottleneck in behavior.

    View details for DOI 10.1073/pnas.1822137116

    View details for Web of Science ID 000467804000062

    View details for PubMedID 30962384

    View details for PubMedCentralID PMC6525533

  • Combining Citizen Science and Deep Learning to Amplify Expertise in Neuroimaging FRONTIERS IN NEUROINFORMATICS Keshavan, A., Yeatman, J. D., Rokem, A. 2019; 13: 29

    Abstract

    Big Data promises to advance science through data-driven discovery. However, many standard lab protocols rely on manual examination, which is not feasible for large-scale datasets. Meanwhile, automated approaches lack the accuracy of expert examination. We propose to (1) start with expertly labeled data, (2) amplify labels through web applications that engage citizen scientists, and (3) train machine learning on amplified labels, to emulate the experts. Demonstrating this, we developed a system to quality control brain magnetic resonance images. Expert-labeled data were amplified by citizen scientists through a simple web interface. A deep learning algorithm was then trained to predict data quality, based on citizen scientist labels. Deep learning performed as well as specialized algorithms for quality control (AUC = 0.99). Combining citizen science and deep learning can generalize and scale expert decision making; this is particularly important in disciplines where specialized, automated tools do not yet exist.

    View details for DOI 10.3389/fninf.2019.00029

    View details for Web of Science ID 000467471700001

    View details for PubMedID 31139070

    View details for PubMedCentralID PMC6517786

  • Applying microstructural models to understand the role of white matter in cognitive development Huber, E., Henriques, R., Owen, J. P., Rokem, A., Yeatman, J. D. ELSEVIER SCI LTD. 2019: 100624

    Abstract

    Diffusion MRI (dMRI) holds great promise for illuminating the biological changes that underpin cognitive development. The diffusion of water molecules probes the cellular structure of brain tissue, and biophysical modeling of the diffusion signal can be used to make inferences about specific tissue properties that vary over development or predict cognitive performance. However, applying these models to study development requires that the parameters can be reliably estimated given the constraints of data collection with children. Here we collect repeated scans using a typical multi-shell diffusion MRI protocol in a group of children (ages 7-12) and use two popular modeling techniques to examine individual differences in white matter structure. We first assess scan-rescan reliability of model parameters and show that axon water faction can be reliably estimated from a relatively fast acquisition, without applying spatial smoothing or de-noising. We then investigate developmental changes in the white matter, and individual differences that correlate with reading skill. Specifically, we test the hypothesis that previously reported correlations between reading skill and diffusion anisotropy in the corpus callosum reflect increased axon water fraction in poor readers. Both models support this interpretation, highlighting the utility of these approaches for testing specific hypotheses about cognitive development.

    View details for DOI 10.1016/j.dcn.2019.100624

    View details for Web of Science ID 000468166900022

    View details for PubMedID 30927705

  • Intensive Summer Intervention Drives Linear Growth of Reading Skill in Struggling Readers. Frontiers in psychology Donnelly, P. M., Huber, E., Yeatman, J. D. 2019; 10: 1900

    Abstract

    A major achievement of reading research has been the development of effective intervention programs for struggling readers. Most intervention studies employ a pre-post design, to examine efficacy, but this precludes the study of growth curves over the course of the intervention program. Determining the time-course of improvement is essential for cost-effective, evidence-based decisions on the optimal intervention dosage. The goal of this study was to analyze reading growth curves during an intensive summer intervention program. A cohort of 31 children (6-12 years) with reading difficulties (N = 21 with dyslexia diagnosis) were enrolled in 160 h of intervention occurring over 8 weeks of summer vacation. We collected behavioral measures over 4 sessions assessing decoding, oral reading fluency, and comprehension. Mixed-effects modeling of longitudinal measurements revealed a linear dose-response relationship between hours of intervention and improvement in reading ability; there was significant linear growth on every measure of reading skill and none of the measures showed non-linear growth trajectories. Decoding skills showed substantial growth [Cohen's d = 0.85 (WJ Basic Reading Skills)], with fluency and comprehension growing more gradually [d = 0.41 (WJ Reading Fluency)]. These results highlight the opportunity to improve reading skills over an intensive, short-term summer intervention program, and the linear dose-response relationship between duration and gains enables educators to set reading level goals and design a treatment plan to achieve them.

    View details for DOI 10.3389/fpsyg.2019.01900

    View details for PubMedID 31507482

    View details for PubMedCentralID PMC6716466

  • Reading ability and phoneme categorization SCIENTIFIC REPORTS O'Brien, G. E., McCloy, D. R., Kubota, E. C., Yeatman, J. D. 2018; 8: 16842

    Abstract

    Dyslexia is associated with abnormal performance on many auditory psychophysics tasks, particularly those involving the categorization of speech sounds. However, it is debated whether those apparent auditory deficits arise from (a) reduced sensitivity to particular acoustic cues, (b) the difficulty of experimental tasks, or (c) unmodeled lapses of attention. Here we investigate the relationship between phoneme categorization and reading ability, with special attention to the nature of the cue encoding the phoneme contrast (static versus dynamic), differences in task paradigm difficulty, and methodological details of psychometric model fitting. We find a robust relationship between reading ability and categorization performance, show that task difficulty cannot fully explain that relationship, and provide evidence that the deficit is not restricted to dynamic cue contrasts, contrary to prior reports. Finally, we demonstrate that improved modeling of behavioral responses suggests that performance does differ between children with dyslexia and typical readers, but that the difference may be smaller than previously reported.

    View details for DOI 10.1038/s41598-018-34823-8

    View details for Web of Science ID 000450167700013

    View details for PubMedID 30442952

    View details for PubMedCentralID PMC6237901

  • Evaluating g-ratio weighted changes in the corpus callosum as a function of age and sex Berman, S., West, K. L., Does, M. D., Yeatman, J. D., Mezer, A. A. ACADEMIC PRESS INC ELSEVIER SCIENCE. 2018: 304–13

    Abstract

    Recent years have seen a growing interest in relating MRI measurements to the structural-biophysical properties of white matter fibers. The fiber g-ratio, defined as the ratio between the inner and outer radii of the axon myelin sheath, is an important structural property of white matter, affecting signal conduction. Recently proposed modeling methods that use a combination of quantitative-MRI signals, enable a measurement of the fiber g-ratio in vivo. Here we use an MRI-based g-ratio estimation to observe the variance of the g-ratio within the corpus callosum, and evaluate sex and age related differences. To estimate the g-ratio we used a model (Stikov et al., 2011; Duval et al., 2017) based on two different WM microstructure parameters: the relative amounts of myelin (myelin volume fraction, MVF) and fibers (fiber volume fraction, FVF) in a voxel. We derived the FVF from the fractional anisotropy (FA), and estimated the MVF by using the lipid and macromolecular tissue volume (MTV), calculated from the proton density (Mezer et al., 2013). In comparison to other methods of estimating the MVF, MTV represents a stable parameter with a straightforward route of acquisition. To establish our model, we first compared histological MVF measurements (West et al., 2016) with the MRI derived MTV. We then implemented our model on a large database of 92 subjects (44 males), aged 7 to 81, in order to evaluate age and sex related changes within the corpus callosum. Our results show that the MTV provides a good estimation of MVF for calculating g-ratio, and produced values from the corpus callosum that correspond to those found in animals ex vivo and are close to the theoretical optimum, as well as to published in vivo data. Our results demonstrate that the MTV derived g-ratio provides a simple and reliable in vivo g-ratio-weighted (GR*) measurement in humans. In agreement with theoretical predictions, and unlike other tissue parameters measured with MRI, the g-ratio estimations were found to be relatively stable with age, and we found no support for a significant sexual dimorphism with age.

    View details for DOI 10.1016/j.neuroimage.2017.06.076

    View details for Web of Science ID 000446316400021

    View details for PubMedID 28673882

    View details for PubMedCentralID PMC5748016

  • Tractography optimization using quantitative T1 mapping in the human optic radiation NEUROIMAGE Schurr, R., Duan, Y., Norcia, A. M., Ogawa, S., Yeatman, J. D., Mezer, A. A. 2018; 181: 645–58

    Abstract

    Diffusion MRI tractography is essential for reconstructing white-matter projections in the living human brain. Yet tractography results miss some projections and falsely identify others. A challenging example is the optic radiation (OR) that connects the thalamus and the primary visual cortex. Here, we tested whether OR tractography can be optimized using quantitative T1 mapping. Based on histology, we proposed that myelin-sensitive T1 values along the OR should remain consistently low compared with adjacent white matter. We found that complementary information from the T1 map allows for increasing the specificity of the reconstructed OR tract by eliminating falsely identified projections. This T1-filtering outperforms other, diffusion-based tractography filters. These results provide evidence that the smooth microstructural signature along the tract can be used as constructive input for tractography. Finally, we demonstrate that this approach can be applied in a case of multiple sclerosis, and generalized to the HCP-available MRI measurements. We conclude that multimodal MRI microstructural information can be used to eliminate spurious tractography results in the case of the OR.

    View details for PubMedID 29936310

  • Rapid and widespread white matter plasticity during an intensive reading intervention NATURE COMMUNICATIONS Huber, E., Donnelly, P. M., Rokem, A., Yeatman, J. D. 2018; 9: 2260

    Abstract

    White matter tissue properties are known to correlate with performance across domains ranging from reading to math, to executive function. Here, we use a longitudinal intervention design to examine experience-dependent growth in reading skills and white matter in grade school-aged, struggling readers. Diffusion MRI data were collected at regular intervals during an 8-week, intensive reading intervention. These measurements reveal large-scale changes throughout a collection of white matter tracts, in concert with growth in reading skill. Additionally, we identify tracts whose properties predict reading skill but remain fixed throughout the intervention, suggesting that some anatomical properties stably predict the ease with which a child learns to read, while others dynamically reflect the effects of experience. These results underscore the importance of considering recent experience when interpreting cross-sectional anatomy-behavior correlations. Widespread changes throughout the white matter may be a hallmark of rapid plasticity associated with an intensive learning experience.

    View details for DOI 10.1038/s41467-018-04627-5

    View details for Web of Science ID 000434649200001

    View details for PubMedID 29884784

    View details for PubMedCentralID PMC5993742

  • Optimizing text for an individual's visual system: The contribution of visual crowding to reading difficulties CORTEX Joo, S., White, A. L., Strodtman, D. J., Yeatman, J. D. 2018; 103: 291–301

    Abstract

    Reading is a complex process that involves low-level visual processing, phonological processing, and higher-level semantic processing. Given that skilled reading requires integrating information among these different systems, it is likely that reading difficulty-known as dyslexia-can emerge from impairments at any stage of the reading circuitry. To understand contributing factors to reading difficulties within individuals, it is necessary to diagnose the function of each component of the reading circuitry. Here, we investigated whether adults with dyslexia who have impairments in visual processing respond to a visual manipulation specifically targeting their impairment. We collected psychophysical measures of visual crowding and tested how each individual's reading performance was affected by increased text-spacing, a manipulation designed to alleviate severe crowding. Critically, we identified a sub-group of individuals with dyslexia showing elevated crowding and found that these individuals read faster when text was rendered with increased letter-, word- and line-spacing. Our findings point to a subtype of dyslexia involving elevated crowding and demonstrate that individuals benefit from interventions personalized to their specific impairments.

    View details for DOI 10.1016/j.cortex.2018.03.013

    View details for Web of Science ID 000436218800022

    View details for PubMedID 29679920

  • A browser-based tool for visualization and analysis of diffusion MRI data NATURE COMMUNICATIONS Yeatman, J. D., Richie-Halford, A., Smith, J. K., Keshavan, A., Rokem, A. 2018; 9: 940

    Abstract

    Human neuroscience research faces several challenges with regards to reproducibility. While scientists are generally aware that data sharing is important, it is not always clear how to share data in a manner that allows other labs to understand and reproduce published findings. Here we report a new open source tool, AFQ-Browser, that builds an interactive website as a companion to a diffusion MRI study. Because AFQ-Browser is portable-it runs in any web-browser-it can facilitate transparency and data sharing. Moreover, by leveraging new web-visualization technologies to create linked views between different dimensions of the dataset (anatomy, diffusion metrics, subject metadata), AFQ-Browser facilitates exploratory data analysis, fueling new discoveries based on previously published datasets. In an era where Big Data is playing an increasingly prominent role in scientific discovery, so will browser-based tools for exploring high-dimensional datasets, communicating scientific discoveries, aggregating data across labs, and publishing data alongside manuscripts.

    View details for DOI 10.1038/s41467-018-03297-7

    View details for Web of Science ID 000426543800007

    View details for PubMedID 29507333

    View details for PubMedCentralID PMC5838108

  • The challenge of mapping the human connectome based on diffusion tractography NATURE COMMUNICATIONS Maier-Hein, K. H., Neher, P. F., Houde, J., Cote, M., Garyfallidis, E., Zhong, J., Chamberland, M., Yeh, F., Lin, Y., Ji, Q., Reddick, W. E., Glass, J. O., Chen, D., Feng, Y., Gao, C., Wu, Y., Ma, J., Renjie, H., Li, Q., Westin, C., Deslauriers-Gauthier, S., Ocegueda Gonzalez, J., Paquette, M., St-Jean, S., Girard, G., Rheault, F., Sidhu, J., Tax, C. W., Guo, F., Mesri, H. Y., David, S., Froeling, M., Heemskerk, A. M., Leemans, A., Bore, A., Pinsard, B., Bedetti, C., Desrosiers, M., Brambati, S., Doyon, J., Sarica, A., Vasta, R., Cerasa, A., Quattrone, A., Yeatman, J., Khan, A. R., Hodges, W., Alexander, S., Romascano, D., Barakovic, M., Auria, A., Esteban, O., Lemkaddem, A., Thiran, J., Cetingul, H., Odry, B. L., Mailhe, B., Nadar, M. S., Pizzagalli, F., Prasad, G., Villalon-Reina, J. E., Galvis, J., Thompson, P. M., Requejo, F., Laguna, P., Lacerda, L., Barrett, R., Dell'Acqua, F., Catani, M., Petit, L., Caruyer, E., Daducci, A., Dyrby, T. B., Holland-Letz, T., Hilgetag, C. C., Stieltjes, B., Descoteaux, M. 2017; 8: 1349

    Abstract

    Tractography based on non-invasive diffusion imaging is central to the study of human brain connectivity. To date, the approach has not been systematically validated in ground truth studies. Based on a simulated human brain data set with ground truth tracts, we organized an open international tractography challenge, which resulted in 96 distinct submissions from 20 research groups. Here, we report the encouraging finding that most state-of-the-art algorithms produce tractograms containing 90% of the ground truth bundles (to at least some extent). However, the same tractograms contain many more invalid than valid bundles, and half of these invalid bundles occur systematically across research groups. Taken together, our results demonstrate and confirm fundamental ambiguities inherent in tract reconstruction based on orientation information alone, which need to be considered when interpreting tractography and connectivity results. Our approach provides a novel framework for estimating reliability of tractography and encourages innovation to address its current limitations.

    View details for DOI 10.1038/s41467-017-01285-x

    View details for Web of Science ID 000414534700013

    View details for PubMedID 29116093

    View details for PubMedCentralID PMC5677006

  • The causal relationship between dyslexia and motion perception reconsidered SCIENTIFIC REPORTS Joo, S., Donnelly, P. M., Yeatman, J. D. 2017; 7: 4185

    Abstract

    It is well established that visual sensitivity to motion is correlated with reading skills. Yet, the causal relationship between motion sensitivity and reading skills has been debated for more than thirty years. One hypothesis posits that dyslexia is caused by deficits in the motion processing pathway. An alternative hypothesis explains the motion processing deficit observed in dyslexia as the consequence of a lack, or poor quality, of reading experience. Here we used an intensive reading intervention program to test the causal relationship between learning to read and motion processing in children. Our data show that, while the reading intervention enhanced reading abilities, learning to read did not affect motion sensitivity. Motion sensitivity remained stable over the course of the intervention. Furthermore, the motion sensitivity deficit did not negatively impact the learning process. Children with poor motion sensitivity showed the same improvement in reading skills as children with typical motion sensitivity. Our findings call into question the view that motion processing deficits are due to poor reading experience. We propose that the correlation between the two measures arises from other common mechanisms, or that motion processing deficits are among a collection of correlated risk factors for reading difficulties.

    View details for DOI 10.1038/s41598-017-04471-5

    View details for Web of Science ID 000404118700075

    View details for PubMedID 28646168

    View details for PubMedCentralID PMC5482857

  • Bottom-up and top-down computations in word-and face-selective cortex ELIFE Kay, K. N., Yeatman, J. D. 2017; 6

    Abstract

    The ability to read a page of text or recognize a person's face depends on category-selective visual regions in ventral temporal cortex (VTC). To understand how these regions mediate word and face recognition, it is necessary to characterize how stimuli are represented and how this representation is used in the execution of a cognitive task. Here, we show that the response of a category-selective region in VTC can be computed as the degree to which the low-level properties of the stimulus match a category template. Moreover, we show that during execution of a task, the bottom-up representation is scaled by the intraparietal sulcus (IPS), and that the level of IPS engagement reflects the cognitive demands of the task. These results provide an account of neural processing in VTC in the form of a model that addresses both bottom-up and top-down effects and quantitatively predicts VTC responses.

    View details for DOI 10.7554/eLife.22341

    View details for Web of Science ID 000397630300001

    View details for PubMedID 28226243

    View details for PubMedCentralID PMC5358981

  • The corticospinal tract profile in amyotrophic lateral sclerosis HUMAN BRAIN MAPPING Sarica, A., Cerasa, A., Valentino, P., Yeatman, J., Trotta, M., Barone, S., Granata, A., Nistico, R., Perrotta, P., Pucci, F., Quattrone, A. 2017; 38 (2): 727–39

    Abstract

    This work evaluates the potential in diagnostic application of a new advanced neuroimaging method, which delineates the profile of tissue properties along the corticospinal tract (CST) in amyotrophic lateral sclerosis (ALS), by means of diffusion tensor imaging (DTI). Twenty-four ALS patients and twenty-four demographically matched healthy subjects were enrolled in this study. The Automated Fiber Quantification (AFQ), a tool for the automatic reconstruction of white matter tract profiles, based on a deterministic tractography algorithm to automatically identify the CST and quantify its diffusion properties, was used. At a group level, the highest non-overlapping DTI-related differences were detected in the cerebral peduncle, posterior limb of the internal capsule, and primary motor cortex. Fractional anisotropy (FA) decrease and mean diffusivity (MD) and radial diffusivity (RD) increases were detected when comparing ALS patients to controls. The machine learning approach used to assess the clinical utility of this DTI tool revealed that, by combining all DTI metrics measured along tract between the cerebral peduncle and the corona radiata, a mean 5-fold cross validation accuracy of 80% was reached in discriminating ALS from controls. Our study provides a useful new neuroimaging tool to characterize ALS-related neurodegenerative processes by means of CST profile. We demonstrated that specific microstructural changes in the upper part of the brainstem might be considered as a valid biomarker. With further validations this method has the potential to be considered a promising step toward the diagnostic utility of DTI measures in ALS. Hum Brain Mapp 38:727-739, 2017. © 2016 Wiley Periodicals, Inc.

    View details for DOI 10.1002/hbm.23412

    View details for Web of Science ID 000393786500011

    View details for PubMedID 27659483

  • A fully computable model of stimulus-driven and top-down effects in high-level visual cortex Kay, K., Yeatman, J. SAGE PUBLICATIONS LTD. 2016: 72
  • Aging-Resilient Associations between the Arcuate Fasciculus and Vocabulary Knowledge: Microstructure or Morphology? JOURNAL OF NEUROSCIENCE Teubner-Rhodes, S., Vaden, K. I., Cute, S. L., Yeatman, J. D., Dougherty, R. F., Eckert, M. A. 2016; 36 (27): 7210-7222

    Abstract

    Vocabulary knowledge is one of the few cognitive functions that is relatively preserved in older adults, but the reasons for this relative preservation have not been well delineated. We tested the hypothesis that individual differences in vocabulary knowledge are influenced by arcuate fasciculus macrostructure (i.e., shape and volume) properties that remain stable during the aging process, rather than white matter microstructure that demonstrates age-related declines. Vocabulary was not associated with age compared to pronounced age-related declines in cognitive processing speed across 106 healthy adults (19.92-88.29 years) who participated in this neuroimaging experiment. Fractional anisotropy in the left arcuate fasciculus was significantly related to individual variability in vocabulary. This effect was present despite marked age-related differences in a T1-weighted/T2-weighted ratio (T1w/T2w) estimate of myelin that were observed throughout the left arcuate fasciculus and associated with age-related differences in cognitive processing speed. However, atypical patterns of arcuate fasciculus morphology or macrostructure were associated with decreased vocabulary knowledge. These results suggest that deterioration of tissue in the arcuate fasciculus occurs with normal aging, while having limited impact on tract organization that underlies individual differences in the acquisition and retrieval of lexical and semantic information.Vocabulary knowledge is resilient to widespread age-related declines in brain structure that limit other cognitive functions. We tested the hypothesis that arcuate fasciculus morphology, which supports the development of reading skills that bolster vocabulary, could explain this relative preservation. We disentangled (1) the effects of age-related declines in arcuate microstructure (mean diffusivity; myelin content estimate) that predicted cognitive processing speed but not vocabulary, from (2) relatively stable arcuate macrostructure (shape/volume) that explained significant variance in an age-independent association between fractional anisotropy and vocabulary. This latter result may reflect differences in fiber trajectory and organization that are resilient to aging. We propose that developmental sculpting of the arcuate fasciculus determines acquisition, storage, and access of lexical information across the adult lifespan.

    View details for DOI 10.1523/JNEUROSCI.4342-15.2016

    View details for Web of Science ID 000379021800012

    View details for PubMedID 27383595

    View details for PubMedCentralID PMC4938863

  • A Major Human White Matter Pathway Between Dorsal and Ventral Visual Cortex. Cerebral cortex Takemura, H., Rokem, A., Winawer, J., Yeatman, J. D., Wandell, B. A., Pestilli, F. 2016; 26 (5): 2205-2214

    Abstract

    Human visual cortex comprises many visual field maps organized into clusters. A standard organization separates visual maps into 2 distinct clusters within ventral and dorsal cortex. We combined fMRI, diffusion MRI, and fiber tractography to identify a major white matter pathway, the vertical occipital fasciculus (VOF), connecting maps within the dorsal and ventral visual cortex. We use a model-based method to assess the statistical evidence supporting several aspects of the VOF wiring pattern. There is strong evidence supporting the hypothesis that dorsal and ventral visual maps communicate through the VOF. The cortical projection zones of the VOF suggest that human ventral (hV4/VO-1) and dorsal (V3A/B) maps exchange substantial information. The VOF appears to be crucial for transmitting signals between regions that encode object properties including form, identity, and color and regions that map spatial information.

    View details for DOI 10.1093/cercor/bhv064

    View details for PubMedID 25828567

    View details for PubMedCentralID PMC4830295

  • ABNORMAL WHITE MATTER PROPERTIES IN ADOLESCENT GIRLS WITH ANOREXIA NERVOSA Golden, N. H., Travis, K., Feldman, H., Solomon, M., Nguyen, J., Mezer, A., Yeatman, J. D., Dougherty, R. F. ELSEVIER SCIENCE INC. 2016: S24–S25
  • The posterior arcuate fasciculus and the vertical occipital fasciculus. Cortex; a journal devoted to the study of the nervous system and behavior Weiner, K. S., Yeatman, J. D., Wandell, B. A. 2016

    View details for PubMedID 27132243

  • Temporal Tuning of Word- and Face-selective Cortex. Journal of cognitive neuroscience Yeatman, J. D., Norcia, A. M. 2016; 28 (11): 1820–27

    Abstract

    Sensitivity to temporal change places fundamental limits on object processing in the visual system. An emerging consensus from the behavioral and neuroimaging literature suggests that temporal resolution differs substantially for stimuli of different complexity and for brain areas at different levels of the cortical hierarchy. Here, we used steady-state visually evoked potentials to directly measure three fundamental parameters that characterize the underlying neural response to text and face images: temporal resolution, peak temporal frequency, and response latency. We presented full-screen images of text or a human face, alternated with a scrambled image, at temporal frequencies between 1 and 12 Hz. These images elicited a robust response at the first harmonic that showed differential tuning, scalp topography, and delay for the text and face images. Face-selective responses were maximal at 4 Hz, but text-selective responses, by contrast, were maximal at 1 Hz. The topography of the text image response was strongly left-lateralized at higher stimulation rates, whereas the response to the face image was slightly right-lateralized but nearly bilateral at all frequencies. Both text and face images elicited steady-state activity at more than one apparent latency; we observed early (141-160 msec) and late (>250 msec) text- and face-selective responses. These differences in temporal tuning profiles are likely to reflect differences in the nature of the computations performed by word- and face-selective cortex. Despite the close proximity of word- and face-selective regions on the cortical surface, our measurements demonstrate substantial differences in the temporal dynamics of word- versus face-selective responses.

    View details for PubMedID 27378330

    View details for PubMedCentralID PMC5045815

  • The Structural Properties of Major White Matter Tracts in Strabismic Amblyopia. Investigative ophthalmology & visual science Duan, Y., Norcia, A. M., Yeatman, J. D., Mezer, A. 2015; 56 (9): 5152-5160

    Abstract

    In order to better understand whether white matter structural deficits are present in strabismic amblyopia, we performed a survey of the tissue properties of 28 major white matter tracts using diffusion and quantitative magnetic resonance imaging approaches.We used diffusion-based tensor modeling and a new quantitative T1 protocol to measure fractional anisotropy (FA), mean diffusivity (MD), and myelin-sensitive T1 values. We surveyed tracts in the occipital lobe, including the vertical occipital fasciculus (VOF)-a newly rediscovered tract that bridges dorsal and ventral areas of the occipital lobe, as well as tracts across the rest of the brain.Adults with long-standing strabismic amblyopia show tract-specific elevations in MD. We rank-ordered the tracts on the basis of their MD effect-size. The four most affected tracts were the anterior frontal corpus callosum (ACC), the right VOF, the left inferior longitudinal fasciculus (ILF) and the left optic radiation.The results suggest that most white matter tissue properties are relatively robust to the early visual insult caused by strabismus. However, strabismic amblyopia does affect MD, not only in occipital tracts, such as the VOF and optic radiation, but also in long range association tracts connecting visual cortex to the frontal and temporal lobes (ILF) and connecting the two hemispheres (ACC).

    View details for DOI 10.1167/iovs.15-17097

    View details for PubMedID 26241402

    View details for PubMedCentralID PMC4525637

  • Evaluating the Accuracy of Diffusion MRI Models in White Matter PLOS ONE Rokem, A., Yeatman, J. D., Pestilli, F., Kay, K. N., Mezer, A., van der Walt, S., Wandell, B. A. 2015; 10 (4)

    Abstract

    Models of diffusion MRI within a voxel are useful for making inferences about the properties of the tissue and inferring fiber orientation distribution used by tractography algorithms. A useful model must fit the data accurately. However, evaluations of model-accuracy of commonly used models have not been published before. Here, we evaluate model-accuracy of the two main classes of diffusion MRI models. The diffusion tensor model (DTM) summarizes diffusion as a 3-dimensional Gaussian distribution. Sparse fascicle models (SFM) summarize the signal as a sum of signals originating from a collection of fascicles oriented in different directions. We use cross-validation to assess model-accuracy at different gradient amplitudes (b-values) throughout the white matter. Specifically, we fit each model to all the white matter voxels in one data set and then use the model to predict a second, independent data set. This is the first evaluation of model-accuracy of these models. In most of the white matter the DTM predicts the data more accurately than test-retest reliability; SFM model-accuracy is higher than test-retest reliability and also higher than the DTM model-accuracy, particularly for measurements with (a) a b-value above 1000 in locations containing fiber crossings, and (b) in the regions of the brain surrounding the optic radiations. The SFM also has better parameter-validity: it more accurately estimates the fiber orientation distribution function (fODF) in each voxel, which is useful for fiber tracking.

    View details for DOI 10.1371/journal.pone.0123272

    View details for Web of Science ID 000353016500045

    View details for PubMedID 25879933

    View details for PubMedCentralID PMC4400066

  • Abnormal white matter properties in adolescent girls with anorexia nervosa. NeuroImage. Clinical Travis, K. E., Golden, N. H., Feldman, H. M., Solomon, M., Nguyen, J., Mezer, A., Yeatman, J. D., Dougherty, R. F. 2015; 9: 648-659

    Abstract

    Anorexia nervosa (AN) is a serious eating disorder that typically emerges during adolescence and occurs most frequently in females. To date, very few studies have investigated the possible impact of AN on white matter tissue properties during adolescence, when white matter is still developing. The present study evaluated white matter tissue properties in adolescent girls with AN using diffusion MRI with tractography and T1 relaxometry to measure R1 (1/T1), an index of myelin content. Fifteen adolescent girls with AN (mean age = 16.6 years ± 1.4) were compared to fifteen age-matched girls with normal weight and eating behaviors (mean age = 17.1 years ± 1.3). We identified and segmented 9 bilateral cerebral tracts (18) and 8 callosal fiber tracts in each participant's brain (26 total). Tract profiles were generated by computing measures for fractional anisotropy (FA) and R1 along the trajectory of each tract. Compared to controls, FA in the AN group was significantly decreased in 4 of 26 white matter tracts and significantly increased in 2 of 26 white matter tracts. R1 was significantly decreased in the AN group compared to controls in 11 of 26 white matter tracts. Reduced FA in combination with reduced R1 suggests that the observed white matter differences in AN are likely due to reductions in myelin content. For the majority of tracts, group differences in FA and R1 did not occur within the same tract. The present findings have important implications for understanding the neurobiological factors underlying white matter changes associated with AN and invite further investigations examining associations between white matter properties and specific physiological, cognitive, social, or emotional functions affected in AN.

    View details for DOI 10.1016/j.nicl.2015.10.008

    View details for PubMedID 26740918

  • Abnormal white matter properties in adolescent girls with anorexia nervosa NEUROIMAGE-CLINICAL Travis, K. E., Golden, N. H., Feldman, H. M., Solomon, M., Jenny Nguyen, J., Mezer, A., Yeatman, J. D., Dougherty, R. F. 2015; 9: 648-659

    Abstract

    Anorexia nervosa (AN) is a serious eating disorder that typically emerges during adolescence and occurs most frequently in females. To date, very few studies have investigated the possible impact of AN on white matter tissue properties during adolescence, when white matter is still developing. The present study evaluated white matter tissue properties in adolescent girls with AN using diffusion MRI with tractography and T1 relaxometry to measure R1 (1/T1), an index of myelin content. Fifteen adolescent girls with AN (mean age = 16.6 years ± 1.4) were compared to fifteen age-matched girls with normal weight and eating behaviors (mean age = 17.1 years ± 1.3). We identified and segmented 9 bilateral cerebral tracts (18) and 8 callosal fiber tracts in each participant's brain (26 total). Tract profiles were generated by computing measures for fractional anisotropy (FA) and R1 along the trajectory of each tract. Compared to controls, FA in the AN group was significantly decreased in 4 of 26 white matter tracts and significantly increased in 2 of 26 white matter tracts. R1 was significantly decreased in the AN group compared to controls in 11 of 26 white matter tracts. Reduced FA in combination with reduced R1 suggests that the observed white matter differences in AN are likely due to reductions in myelin content. For the majority of tracts, group differences in FA and R1 did not occur within the same tract. The present findings have important implications for understanding the neurobiological factors underlying white matter changes associated with AN and invite further investigations examining associations between white matter properties and specific physiological, cognitive, social, or emotional functions affected in AN.

    View details for DOI 10.1016/j.nicl.2015.10.008

    View details for Web of Science ID 000373188400069

  • The vertical occipital fasciculus: A century of controversy resolved by in vivo measurements PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Yeatman, J. D., Weiner, K. S., Pestilli, F., Rokem, A., Mezer, A., Wandell, B. A. 2014; 111 (48): E5214-E5223

    Abstract

    The vertical occipital fasciculus (VOF) is the only major fiber bundle connecting dorsolateral and ventrolateral visual cortex. Only a handful of studies have examined the anatomy of the VOF or its role in cognition in the living human brain. Here, we trace the contentious history of the VOF, beginning with its original discovery in monkey by Wernicke (1881) and in human by Obersteiner (1888), to its disappearance from the literature, and recent reemergence a century later. We introduce an algorithm to identify the VOF in vivo using diffusion-weighted imaging and tractography, and show that the VOF can be found in every hemisphere (n = 74). Quantitative T1 measurements demonstrate that tissue properties, such as myelination, in the VOF differ from neighboring white-matter tracts. The terminations of the VOF are in consistent positions relative to cortical folding patterns in the dorsal and ventral visual streams. Recent findings demonstrate that these same anatomical locations also mark cytoarchitectonic and functional transitions in dorsal and ventral visual cortex. We conclude that the VOF is likely to serve a unique role in the communication of signals between regions on the ventral surface that are important for the perception of visual categories (e.g., words, faces, bodies, etc.) and regions on the dorsal surface involved in the control of eye movements, attention, and motion perception.

    View details for DOI 10.1073/pnas.1418503111

    View details for Web of Science ID 000345920800011

    View details for PubMedID 25404310

    View details for PubMedCentralID PMC4260539

  • Speed discrimination predicts word but not pseudo-word reading rate in adults and children BRAIN AND LANGUAGE Main, K. L., Pestilli, F., Mezer, A., Yeatman, J., Martin, R., Phipps, S., Wandell, B. 2014; 138: 27-37

    Abstract

    Visual processing in the magnocellular pathway is a reputed influence on word recognition and reading performance. However, the mechanisms behind this relationship are still unclear. To explore this concept, we measured reading rate, speed-discrimination, and contrast detection thresholds in adults and children with a wide range of reading abilities. We found that speed discrimination thresholds are higher in children than in adults and are correlated with age. Speed discrimination thresholds are also correlated with reading rates but only for real words, not pseudo-words. Conversely, we found no correlations between contrast detection thresholds and the reading rates. We also found no correlations between speed discrimination or contrast detection and WASI subtest scores. These findings indicate that familiarity is a factor in magnocellular operations that may influence reading rate. We suggest this effect supports the idea that the magnocellular pathway contributes to word reading through an analysis of letter position.

    View details for DOI 10.1016/j.bandl.2014.09.003

    View details for Web of Science ID 000345949700004

    View details for PubMedID 25278418

    View details for PubMedCentralID PMC4300234

  • Evaluation and statistical inference for human connectomes NATURE METHODS Pestilli, F., Yeatman, J. D., Rokem, A., Kay, K. N., Wandell, B. A. 2014; 11 (10): 1058-1063

    Abstract

    Diffusion-weighted imaging coupled with tractography is currently the only method for in vivo mapping of human white-matter fascicles. Tractography takes diffusion measurements as input and produces the connectome, a large collection of white-matter fascicles, as output. We introduce a method to evaluate the evidence supporting connectomes. Linear fascicle evaluation (LiFE) takes any connectome as input and predicts diffusion measurements as output, using the difference between the measured and predicted diffusion signals to quantify the prediction error. We use the prediction error to evaluate the evidence that supports the properties of the connectome, to compare tractography algorithms and to test hypotheses about tracts and connections.

    View details for Web of Science ID 000342719100026

    View details for PubMedCentralID PMC4180802

  • White Matter Consequences of Retinal Receptor and Ganglion Cell Damage INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE Ogawa, S., Takemura, H., Horiguchi, H., Terao, M., Haji, T., Pestilli, F., Yeatman, J. D., Tsuneoka, H., Wandell, B. A., Masuda, Y. 2014; 55 (10)

    Abstract

    Patients with Leber hereditary optic neuropathy (LHON) and cone-rod dystrophy (CRD) have central vision loss; but CRD damages the retinal photoreceptor layer, and LHON damages the retinal ganglion cell (RGC) layer. Using diffusion MRI, we measured how these two types of retinal damage affect the optic tract (ganglion cell axons) and optic radiation (geniculo-striate axons).Adult onset CRD (n = 5), LHON (n = 6), and healthy controls (n = 14) participated in the study. We used probabilistic fiber tractography to identify the optic tract and the optic radiation. We compared axial and radial diffusivity at many positions along the optic tract and the optic radiation.In both types of patients, diffusion measures within the optic tract and the optic radiation differ from controls. The optic tract change is principally a decrease in axial diffusivity; the optic radiation change is principally an increase in radial diffusivity.Both photoreceptor layer (CRD) and retinal ganglion cell (LHON) retinal disease causes substantial change in the visual white matter. These changes can be measured using diffusion MRI. The diffusion changes measured in the optic tract and the optic radiation differ, suggesting that they are caused by different biological mechanisms.

    View details for DOI 10.1167/iovs.14-14737

    View details for Web of Science ID 000344730500047

    View details for PubMedCentralID PMC4215745

  • Lifespan maturation and degeneration of human brain white matter NATURE COMMUNICATIONS Yeatman, J. D., Wandell, B. A., Mezer, A. A. 2014; 5

    Abstract

    Properties of human brain tissue change across the lifespan. Here we model these changes in the living human brain by combining quantitative magnetic resonance imaging (MRI) measurements of R1 (1/T1) with diffusion MRI and tractography (N=102, ages 7-85). The amount of R1 change during development differs between white-matter fascicles, but in each fascicle the rate of development and decline are mirror-symmetric; the rate of R1 development as the brain approaches maturity predicts the rate of R1 degeneration in aging. Quantitative measurements of macromolecule tissue volume (MTV) confirm that R1 is an accurate index of the growth of new brain tissue. In contrast to R1, diffusion development follows an asymmetric time-course with rapid childhood changes but a slow rate of decline in old age. Together, the time-courses of R1 and diffusion changes demonstrate that multiple biological processes drive changes in white-matter tissue properties over the lifespan.

    View details for DOI 10.1038/ncomms5932

    View details for Web of Science ID 000209869600001

    View details for PubMedCentralID PMC4238904

  • Disease in the photoreceptors (JMD) or retinal ganglion cells (LHON) affects optic tract and radiation tissue properties Ogawa, S., Takemura, H., Horiguchi, H., Terao, M., Haji, T., Pestilli, F., Yeatman, J. D., Tsuneoka, H., Wandell, B. A., Masuda, Y. ASSOC RESEARCH VISION OPHTHALMOLOGY INC. 2014
  • Diffusion properties of major white matter tracts in young, typically developing children NEUROIMAGE Johnson, R. T., Yeatman, J. D., Wandell, B. A., Buonocore, M. H., Amaral, D. G., Nordahl, C. W. 2014; 88: 143-154

    Abstract

    Brain development occurs rapidly during the first few years of life involving region-specific changes in both gray matter and white matter. Due to the inherent difficulties in acquiring magnetic resonance imaging data in young children, little is known about the properties of white matter in typically developing toddlers. In the context of an ongoing study of young children with autism spectrum disorder, we collected diffusion-weighted imaging data during natural nocturnal sleep in a sample of young (mean age=35months) typically developing male and female (n=41 and 25, respectively) children. Axial diffusivity, radial diffusivity, mean diffusivity and fractional anisotropy were measured at 99 points along the length of 18 major brain tracts. Influences of hemisphere, age, sex, and handedness were examined. We find that diffusion properties vary significantly along the length of the majority of tracks. We also identify hemispheric and sex differences in diffusion properties in several tracts. Finally, we find the relationship between age and diffusion parameters changes along the tract length illustrating variability in age-related white-matter development at the tract level.

    View details for DOI 10.1016/j.neuroimage.2013.11.025

    View details for Web of Science ID 000332052000016

    View details for PubMedCentralID PMC4029877

  • Lifespan maturation and degeneration of human brain white matter. Nature communications Yeatman, J. D., Wandell, B. A., Mezer, A. A. 2014; 5: 4932-?

    Abstract

    Properties of human brain tissue change across the lifespan. Here we model these changes in the living human brain by combining quantitative magnetic resonance imaging (MRI) measurements of R1 (1/T1) with diffusion MRI and tractography (N=102, ages 7-85). The amount of R1 change during development differs between white-matter fascicles, but in each fascicle the rate of development and decline are mirror-symmetric; the rate of R1 development as the brain approaches maturity predicts the rate of R1 degeneration in aging. Quantitative measurements of macromolecule tissue volume (MTV) confirm that R1 is an accurate index of the growth of new brain tissue. In contrast to R1, diffusion development follows an asymmetric time-course with rapid childhood changes but a slow rate of decline in old age. Together, the time-courses of R1 and diffusion changes demonstrate that multiple biological processes drive changes in white-matter tissue properties over the lifespan.

    View details for DOI 10.1038/ncomms5932

    View details for PubMedID 25230200

    View details for PubMedCentralID PMC4238904

  • Developmental Changes within White Matter Tracts of Healthy Children Age 9 to 16 Years Old Yeatman, J. D., Myall, N. J., Dougherty, R. F., Wandell, B. A., Feldman, H. M. LIPPINCOTT WILLIAMS & WILKINS. 2013: S5
  • Anatomy of the visual word form area: Adjacent cortical circuits and long-range white matter connections. Brain and language Yeatman, J. D., Rauschecker, A. M., Wandell, B. A. 2013; 125 (2): 146-155

    Abstract

    Circuitry in ventral occipital-temporal cortex is essential for seeing words. We analyze the circuitry within a specific ventral-occipital region, the visual word form area (VWFA). The VWFA is immediately adjacent to the retinotopically organized VO-1 and VO-2 visual field maps and lies medial and inferior to visual field maps within motion selective human cortex. Three distinct white matter fascicles pass within close proximity to the VWFA: (1) the inferior longitudinal fasciculus, (2) the inferior frontal occipital fasciculus, and (3) the vertical occipital fasciculus. The vertical occipital fasciculus terminates in or adjacent to the functionally defined VWFA voxels in every individual. The vertical occipital fasciculus projects dorsally to language and reading related cortex. The combination of functional responses from cortex and anatomical measures in the white matter provides an overview of how the written word is encoded and communicated along the ventral occipital-temporal circuitry for seeing words.

    View details for DOI 10.1016/j.bandl.2012.04.010

    View details for PubMedID 22632810

    View details for PubMedCentralID PMC3432298

  • Biological development of reading circuits. Current opinion in neurobiology Wandell, B. A., Yeatman, J. D. 2013; 23 (2): 261-268

    Abstract

    Human neuroimaging is expanding our understanding of the biological processes that are essential for healthy brain function. Methods such as diffusion weighted imaging provide insights into white matter fascicles, growth and pruning of dendritic arbors and axons, and properties of glia. This review focuses on what we have learned from diffusion imaging about these processes and the development of reading circuitry in the human brain. Understanding reading circuitry development may suggest ways to improve how we teach children to read.

    View details for DOI 10.1016/j.conb.2012.12.005

    View details for PubMedID 23312307

    View details for PubMedCentralID PMC3622751

  • Language and reading skills in school-aged children and adolescents born preterm are associated with white matter properties on diffusion tensor imaging NEUROPSYCHOLOGIA Feldman, H. M., Lee, E. S., Yeatman, J. D., Yeom, K. W. 2012; 50 (14): 3348-3362

    Abstract

    Children born preterm are at risk for deficits in language and reading. They are also at risk for injury to the white matter of the brain. The goal of this study was to determine whether performance in language and reading skills would be associated with white matter properties in children born preterm and full-term. Children born before 36 weeks gestation (n=23, mean±SD age 12.5±2.0 years, gestational age 28.7±2.5 weeks, birth weight 1184±431 g) and controls born after 37 weeks gestation (n=19, 13.1±2.1 years, 39.3±1.0 weeks, 3178±413 g) underwent a battery of language and reading tests. Diffusion tensor imaging (DTI) scans were processed using tract-based spatial statistics to generate a core white matter skeleton that was anatomically comparable across participants. Fractional anisotropy (FA) was the diffusion property used in analyses. In the full-term group, no regions of the whole FA-skeleton were associated with language and reading. In the preterm group, regions of the FA-skeleton were significantly associated with verbal IQ, linguistic processing speed, syntactic comprehension, and decoding. Combined, the regions formed a composite map of 22 clusters on 15 tracts in both hemispheres and in the ventral and dorsal streams. ROI analyses in the preterm group found that several of these regions also showed positive associations with receptive vocabulary, verbal memory, and reading comprehension. Some of the same regions showed weak negative correlations within the full-term group. Exploratory multiple regression in the preterm group found that specific white matter pathways were related to different aspects of language processing and reading, accounting for 27-44% of the variance. The findings suggest that higher performance in language and reading in a group of preterm but not full-term children is associated with higher fractional anisotropy of a bilateral and distributed white matter network.

    View details for DOI 10.1016/j.neuropsychologia.2012.10.014

    View details for PubMedID 23088817

  • Development of white matter and reading skills PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Yeatman, J. D., Dougherty, R. F., Ben-Shachar, M., Wandell, B. A. 2012; 109 (44): E3045-E3053

    Abstract

    White matter tissue properties are highly correlated with reading proficiency; we would like to have a model that relates the dynamics of an individual's white matter development to their acquisition of skilled reading. The development of cerebral white matter involves multiple biological processes, and the balance between these processes differs between individuals. Cross-sectional measures of white matter mask the interplay between these processes and their connection to an individual's cognitive development. Hence, we performed a longitudinal study to measure white-matter development (diffusion-weighted imaging) and reading development (behavioral testing) in individual children (age 7-15 y). The pattern of white-matter development differed significantly among children. In the left arcuate and left inferior longitudinal fasciculus, children with above-average reading skills initially had low fractional anisotropy (FA) that increased over the 3-y period, whereas children with below-average reading skills had higher initial FA that declined over time. We describe a dual-process model of white matter development comprising biological processes with opposing effects on FA, such as axonal myelination and pruning, to explain the pattern of results.

    View details for DOI 10.1073/pnas.1206792109

    View details for Web of Science ID 000311149900014

    View details for PubMedID 23045658

    View details for PubMedCentralID PMC3497768

  • Differences in neural activation between preterm and full term born adolescents on a sentence comprehension task: Implications for educational accommodations DEVELOPMENTAL COGNITIVE NEUROSCIENCE Barde, L. H., Yeatman, J. D., Lee, E. S., Glover, G., Feldman, H. M. 2012; 2: S114-S128

    Abstract

    Adolescent survivors of preterm birth experience persistent functional problems that negatively impact academic outcomes, even when standardized measures of cognition and language suggest normal ability. In this fMRI study, we compared the neural activation supporting auditory sentence comprehension in two groups of adolescents (ages 9-16 years); sentences varied in length and syntactic difficulty. Preterms (n=18, mean gestational age 28.8 weeks) and full terms (n=14) had scores on verbal IQ, receptive vocabulary, and receptive language tests that were within or above normal limits and similar between groups. In early and late phases of the trial, we found interactions by group and length; in the late phase, we also found a group by syntactic difficulty interaction. Post hoc tests revealed that preterms demonstrated significant activation in the left and right middle frontal gyri as syntactic difficulty increased. ANCOVA showed that the interactions could not be attributed to differences in age, receptive language skill, or reaction time. Results are consistent with the hypothesis that preterm birth modulates brain-behavior relations in sentence comprehension as task demands increase. We suggest preterms' differences in neural processing may indicate a need for educational accommodations, even when formal test scores indicate normal academic achievement.

    View details for DOI 10.1016/j.dcn.2011.10.002

    View details for PubMedID 22682901

  • Learning to See Words ANNUAL REVIEW OF PSYCHOLOGY, VOL 63 Wandell, B. A., Rauschecker, A. M., Yeatman, J. D. 2012; 63: 31-53

    Abstract

    Skilled reading requires recognizing written words rapidly; functional neuroimaging research has clarified how the written word initiates a series of responses in visual cortex. These responses are communicated to circuits in ventral occipitotemporal (VOT) cortex that learn to identify words rapidly. Structural neuroimaging has further clarified aspects of the white matter pathways that communicate reading signals between VOT and language systems. We review this circuitry, its development, and its deficiencies in poor readers. This review emphasizes data that measure the cortical responses and white matter pathways in individual subjects rather than group differences. Such methods have the potential to clarify why a child has difficulty learning to read and to offer guidance about the interventions that may be useful for that child.

    View details for DOI 10.1146/annurev-psych-120710-100434

    View details for Web of Science ID 000299709900002

    View details for PubMedID 21801018

    View details for PubMedCentralID PMC3228885

  • Anatomical Properties of the Arcuate Fasciculus Predict Phonological and Reading Skills in Children JOURNAL OF COGNITIVE NEUROSCIENCE Yeatman, J. D., Dougherty, R. F., Rykhlevskaia, E., Sherbondy, A. J., Deutsch, G. K., Wandell, B. A., Ben-Shachar, M. 2011; 23 (11): 3304-3317

    Abstract

    For more than a century, neurologists have hypothesized that the arcuate fasciculus carries signals that are essential for language function; however, the relevance of the pathway for particular behaviors is highly controversial. The primary objective of this study was to use diffusion tensor imaging to examine the relationship between individual variation in the microstructural properties of arcuate fibers and behavioral measures of language and reading skills. A second objective was to use novel fiber-tracking methods to reassess estimates of arcuate lateralization. In a sample of 55 children, we found that measurements of diffusivity in the left arcuate correlate with phonological awareness skills and arcuate volume lateralization correlates with phonological memory and reading skills. Contrary to previous investigations that report the absence of the right arcuate in some subjects, we demonstrate that new techniques can identify the pathway in every individual. Our results provide empirical support for the role of the arcuate fasciculus in the development of reading skills.

    View details for Web of Science ID 000295869500011

    View details for PubMedID 21568636

  • Specific language and reading skills in school-aged children and adolescents are associated with prematurity after controlling for IQ NEUROPSYCHOLOGIA Lee, E. S., Yeatman, J. D., Luna, B., Feldman, H. M. 2011; 49 (5): 906-913

    Abstract

    Although studies of long-term outcomes of children born preterm consistently show low intelligence quotient (IQ) and visual-motor impairment, studies of their performance in language and reading have found inconsistent results. In this study, we examined which specific language and reading skills were associated with prematurity independent of the effects of gender, socioeconomic status (SES), and IQ. Participants from two study sites (N=100) included 9-16-year old children born before 36 weeks gestation and weighing less than 2500 grams (preterm group, n=65) compared to children born at 37 weeks gestation or more (full-term group, n=35). Children born preterm had significantly lower scores than full-term controls on Performance IQ, Verbal IQ, receptive and expressive language skills, syntactic comprehension, linguistic processing speed, verbal memory, decoding, and reading comprehension but not on receptive vocabulary. Using MANCOVA, we found that SES, IQ, and prematurity all contributed to the variance in scores on a set of six non-overlapping measures of language and reading. Simple regression analyses found that after controlling for SES and Performance IQ, the degree of prematurity as measured by gestational age group was a significant predictor of linguistic processing speed, β=-.27, p<.05, R(2)=.07, verbal memory, β=.31, p<.05, R(2)=.09, and reading comprehension, β=.28, p<.05, R(2)=.08, but not of receptive vocabulary, syntactic comprehension, or decoding. The language and reading domains where prematurity had a direct effect can be classified as fluid as opposed to crystallized functions and should be monitored in school-aged children and adolescents born preterm.

    View details for DOI 10.1016/j.neuropsychologia.2010.12.038

    View details for PubMedID 21195100

  • Diffusion Tensor Imaging: A Review for Pediatric Researchers and Clinicians JOURNAL OF DEVELOPMENTAL AND BEHAVIORAL PEDIATRICS Feldman, H. M., Yeatman, J. D., Lee, E. S., Barde, L. H., Gaman-Bean, S. 2010; 31 (4): 346-356

    Abstract

    Diffusion tensor imaging (DTI) is a magnetic resonance imaging technique that allows for the visualization and characterization of the white matter tracts of the brain in vivo. DTI does not assess white matter directly. Rather, it capitalizes on the fact that diffusion is isotropic (equal in all directions) in cerebral spinal fluid and cell bodies but anisotropic (greater in one direction than the other directions) in axons that comprise white matter. It provides quantitative information about the degree and direction of water diffusion within individual units of volume within the magnetic resonance image, and by inference, about the integrity of white matter. Measures from DTI can be applied throughout the brain or to regions of interest. Fiber tract reconstruction, or tractography, creates continuous 3-dimensional tracts by sequentially piecing together estimates of fiber orientation from the direction of diffusion within individual volume units. DTI has increased our understanding of white matter structure and function. DTI shows nonlinear growth of white matter tracts from childhood to adulthood. Delayed maturation of the white matter in the frontal lobes may explain the continued growth of cognitive control into adulthood. Relative to good readers, adults and children who are poor readers have evidence of white matter differences in a specific region of the temporo-parietal lobe, implicating differences in connections among brain regions as a factor in reading disorder. Measures from DTI changed in poor readers who improved their reading skills after intense remediation. DTI documents injury to white matter tracts after prematurity. Measures indicative of white matter injury are associated with motor and cognitive impairment in children born prematurely. Further research on DTI is necessary before it can become a routine clinical procedure.

    View details for DOI 10.1097/DBP.0b013e3181dcaa8b

    View details for PubMedID 20453582