Honors & Awards
Career Development Award (K99/R00), NICHD (2018 - 2023)
NIH Loan Repayment Award, NICHD (2018 - 2020)
CNI Seed-grant Award, Stanford Center for Cognitive and Neurobiological Imaging (2017)
Evolutionary Precursors and Early Development of Basic Number Processing Conference Travel Award, NIH (2013)
Dissertation Award, Utah State University (2012 - 2013)
Walter R. Borg Scholarship and Research Productivity Award, Utah State University, Department of Psychology (2010)
Robert E. Prytulla Scholarship for Excellence in Psychological Studies, Middle Tennessee State University, Department of Psychology (2007)
Postdoctoral Fellowship, Center for Interdisciplinary Brain Sciences Research, Division of Brain Sciences, School of Medicine, Stanford University (2013)
Ph.D., Utah State University, Experimental Psychology (2013)
M.A., Middle Tennessee State University, Cognitive Psychology (2009)
B.A., New Mexico State University, Psychology (2004)
Effect of Turner Syndrome on Number Sense
This study evaluates approximate number sense (ANS) in children, adolescents, and adult women with Turner syndrome compared to age-matched healthy peers. One primary aim of this project is to assess the effectiveness of an online ANS training tool in enhancing complex mathematics ability. Participants will undergo weekly training sessions in their own home. Half of the participants will complete 2 training sessions a week for 8 weeks, and the second half will complete 1 training session for 8 weeks.
Stanford is currently not accepting patients for this trial. For more information, please contact Joseph M Baker, Ph.D., (650) 498-4538.
fNIRS measurement of cortical activation and functional connectivity during a visuospatial working memory task.
2018; 13 (8): e0201486
Demands on visuospatial working memory are a ubiquitous part of everyday life. As such, significant efforts have been made to understand how the brain responds to these demands in real-world environments. Multiple brain imaging studies have highlighted a fronto-parietal cortical network that underlies visuospatial working memory, is modulated by cognitive load, and that appears to respond uniquely to encoding versus retrieval components. Furthermore, multiple studies have identified functional connectivity in regions of the fronto-parietal network during working memory tasks. Together, these findings have helped outline important aspects of the neural architecture that underlies visuospatial working memory. Here, we provide results from the first fNIRS-based investigation of fronto-parietal signatures of cortical activation and functional connectivity during a computer-based visuospatial working memory task. Our results indicate that the local maxima of cortical activation and functional coherence do not necessarily overlap spatially, and that cortical activation is significantly more susceptible to task-specific demands compared to functional connectivity. These results highlight important and novel information regarding neurotypical signatures of cortical activation and functional connectivity during visuospatial working memory. Our findings also demonstrate the utility of fNIRS for interrogating these cognitive processes.
View details for DOI 10.1371/journal.pone.0201486
View details for PubMedID 30071072
Portable Functional Neuroimaging as an Environmental Epidemiology Tool: A How-To Guide for the Use of fNIRS in Field Studies
ENVIRONMENTAL HEALTH PERSPECTIVES
2017; 125 (9): 094502
The widespread application of functional neuroimaging within the field of environmental epidemiology has the potential to greatly enhance our understanding of how environmental toxicants affect brain function. Because many epidemiological studies take place in remote and frequently changing environments, it is necessary that the primary neuroimaging approach adopted by the epidemiology community be robust to many environments, easy to use, and, preferably, mobile. Here, we outline our use of functional near-infrared spectroscopy (fNIRS) to collect functional brain imaging data from Costa Rican farm workers enrolled in an epidemiological study on the health effects of chronic pesticide exposure. While couched in this perspective, we focus on the methodological considerations that are necessary to conduct a mobile fNIRS study in a diverse range of environments. Thus, this guide is intended to be generalizable to all research scenarios and projects in which fNIRS may be used to collect functional brain imaging data in epidemiological field surveys. https://doi.org/10.1289/EHP2049.
View details for DOI 10.1289/EHP2049
View details for Web of Science ID 000413792800006
View details for PubMedID 28937962
View details for PubMedCentralID PMC5915206
Sex differences in neural and behavioral signatures of cooperation revealed by fNIRS hyperscanning
Researchers from multiple fields have sought to understand how sex moderates human social behavior. While over 50 years of research has revealed differences in cooperation behavior of males and females, the underlying neural correlates of these sex differences have not been explained. A missing and fundamental element of this puzzle is an understanding of how the sex composition of an interacting dyad influences the brain and behavior during cooperation. Using fNIRS-based hyperscanning in 111 same- and mixed-sex dyads, we identified significant behavioral and neural sex-related differences in association with a computer-based cooperation task. Dyads containing at least one male demonstrated significantly higher behavioral performance than female/female dyads. Individual males and females showed significant activation in the right frontopolar and right inferior prefrontal cortices, although this activation was greater in females compared to males. Female/female dyad's exhibited significant inter-brain coherence within the right temporal cortex, while significant coherence in male/male dyads occurred in the right inferior prefrontal cortex. Significant coherence was not observed in mixed-sex dyads. Finally, for same-sex dyads only, task-related inter-brain coherence was positively correlated with cooperation task performance. Our results highlight multiple important and previously undetected influences of sex on concurrent neural and behavioral signatures of cooperation.
View details for DOI 10.1038/srep26492
View details for Web of Science ID 000377330900001
View details for PubMedID 27270754
View details for PubMedCentralID PMC4897646
A meta-analysis of math performance in Turner syndrome.
Developmental medicine and child neurology
2016; 58 (2): 123-130
Studies investigating the relationship between Turner syndrome and math learning disability have used a wide variation of tasks designed to test various aspects of mathematical competencies. Although these studies have revealed much about the math deficits common to Turner syndrome, their diversity makes comparisons between individual studies difficult. As a result, the consistency of outcomes among these diverse measures remains unknown. The overarching aim of this review is to provide a systematic meta-analysis of the differences in math and number performance between females with Turner syndrome and age-matched neurotypical peers.We provide a meta-analysis of behavioral performance in Turner syndrome relative to age-matched neurotypical populations on assessments of math and number aptitude. In total, 112 comparisons collected across 17 studies were included.Although 54% of all statistical comparisons in our analyses failed to reject the null hypothesis, our results indicate that meaningful group differences exist on all comparisons except those that do not require explicit calculation.Taken together, these results help elucidate our current understanding of math and number weaknesses in Turner syndrome, while highlighting specific topics that require further investigation.
View details for DOI 10.1111/dmcn.12961
View details for PubMedID 26566693
Mind over motor mapping: Driver response to changing vehicle dynamics.
Human brain mapping
Improvements in vehicle safety require understanding of the neural systems that support the complex, dynamic task of real-world driving. We used functional near infrared spectroscopy (fNIRS) and pupilometry to quantify cortical and physiological responses during a realistic, simulated driving task in which vehicle dynamics were manipulated. Our results elucidate compensatory changes in driver behavior in response to changes in vehicle handling. We also describe associated neural and physiological responses under different levels of mental workload. The increased cortical activation we observed during the late phase of the experiment may indicate motor learning in prefrontal-parietal networks. Finally, relationships among cortical activation, steering control, and individual personality traits suggest that individual brain states and traits may be useful in predicting a driver's response to changes in vehicle dynamics. Results such as these will be useful for informing the design of automated safety systems that facilitate safe and supportive driver-car communication.
View details for DOI 10.1002/hbm.24220
View details for PubMedID 29885097
A Proof of Concept Study of Function-Based Statistical Analysis of fNIRS Data: Syntax Comprehension in Children with Specific Language Impairment Compared to Typically-Developing Controls
FRONTIERS IN BEHAVIORAL NEUROSCIENCE
Functional near infrared spectroscopy (fNIRS) is a neuroimaging technology that enables investigators to indirectly monitor brain activity in vivo through relative changes in the concentration of oxygenated and deoxygenated hemoglobin. One of the key features of fNIRS is its superior temporal resolution, with dense measurements over very short periods of time (100 ms increments). Unfortunately, most statistical analysis approaches in the existing literature have not fully utilized the high temporal resolution of fNIRS. For example, many analysis procedures are based on linearity assumptions that only extract partial information, thereby neglecting the overall dynamic trends in fNIRS trajectories. The main goal of this article is to assess the ability of a functional data analysis (FDA) approach for detecting significant differences in hemodynamic responses recorded by fNIRS. Children with and without SLI wore two, 3 × 5 fNIRS caps situated over the bilateral parasylvian areas as they completed a language comprehension task. FDA was used to decompose the high dimensional hemodynamic curves into the mean function and a few eigenfunctions to represent the overall trend and variation structures over time. Compared to the most popular GLM, we did not assume any parametric structure and let the data speak for itself. This analysis identified significant differences between the case and control groups in the oxygenated hemodynamic mean trends in the bilateral inferior frontal and left inferior posterior parietal brain regions. We also detected significant group differences in the deoxygenated hemodynamic mean trends in the right inferior posterior parietal cortex and left temporal parietal junction. These findings, using dramatically different approaches, experimental designs, data sets, and foci, were consistent with several other reports, confirming group differences in the importance of these two areas for syntax comprehension. The proposed FDA was consistent with the temporal characteristics of fNIRS, thus providing an alternative methodology for fNIRS analyses.
View details for DOI 10.3389/fnbeh.2076.00108
View details for Web of Science ID 000377241800001
View details for PubMedID 27375448
View details for PubMedCentralID PMC4894897
- Using Open-Response Fraction Items to Explore the Relationship Between Instructional Modalities and Students' Solution Strategies INTERNATIONAL JOURNAL OF EDUCATION IN MATHEMATICS SCIENCE AND TECHNOLOGY 2016; 4 (2): 112–32
- Cortical Activations During a Computer-Based Fraction Learning Game: Preliminary Results from a Pilot Study TECHNOLOGY KNOWLEDGE AND LEARNING 2015; 20 (3): 339–55
Sensitivity of fNIRS measurement to head motion: An applied use of smartphones in the lab.
Journal of neuroscience methods
2015; 245: 37-43
Powerful computing capabilities in small, easy to use hand-held devices have made smart technologies such as smartphones and tablets ubiquitous in today's society. The capabilities of these devices provide scientists with many tools that can be used to improve the scientific method.Here, we demonstrate how smartphones may be used to quantify the sensitivity of functional near-infrared spectroscopy (fNIRS) signal to head motion. By attaching a smartphone to participants' heads during the fNIRS scan, we were able to capture data describing the degree of head motion.Our results demonstrate that data recorded from an off-the-shelf smartphone accelerometer may be used to identify correlations between head-movement and fNIRS signal change. Furthermore, our results identify correlations between the magnitudes of head-movement and signal artifact, as well as a relationship between the direction of head movement and the location of the resulting signal noise.These data provide a valuable proof-of-concept for the use of off-the-shelf smart technologies in neuroimaging applications.
View details for DOI 10.1016/j.jneumeth.2015.02.006
View details for PubMedID 25687634
View details for PubMedCentralID PMC4398057
Multiple visual quantitative cues enhance discrimination of dynamic stimuli during infancy.
Journal of experimental child psychology
2014; 122: 21-32
Infants possess basic capabilities to assess various quantitative properties such as number, size, and time. Preverbal discriminations are approximate, however, and are similarly limited across these dimensions. Here, we present the first evidence that multiple sources of quantitative unisensory information about dynamic stimuli-namely, simultaneous visual cues to changes in both number and surface area-may accelerate 6-month-olds' quantitative competence. Using a habituation-dishabituation paradigm, results from Experiment 1 demonstrate that, when provided with such visual cues to multiple quantitative properties that occur in the same direction, infants make more precise discriminations than has been shown when they receive information about either cue alone. Moreover, Experiment 2 demonstrates that infants' discrimination also benefits from simultaneous visual cues to quantitative changes that occur in opposite directions. Finally, Experiment 3 demonstrates that these findings are not driven by infants' ability to discriminate a 2:3 ratio change in surface area of a dynamic stimulus alone. Thus, we hypothesize that enhanced quantitative discrimination occurs because simultaneous visual quantitative changes may be more salient than single-source information, which could better recruit attention and result in more precise learning and remembering.
View details for DOI 10.1016/j.jecp.2013.12.007
View details for PubMedID 24518049
The evolution of self-control.
Proceedings of the National Academy of Sciences of the United States of America
2014; 111 (20): E2140-8
Cognition presents evolutionary research with one of its greatest challenges. Cognitive evolution has been explained at the proximate level by shifts in absolute and relative brain volume and at the ultimate level by differences in social and dietary complexity. However, no study has integrated the experimental and phylogenetic approach at the scale required to rigorously test these explanations. Instead, previous research has largely relied on various measures of brain size as proxies for cognitive abilities. We experimentally evaluated these major evolutionary explanations by quantitatively comparing the cognitive performance of 567 individuals representing 36 species on two problem-solving tasks measuring self-control. Phylogenetic analysis revealed that absolute brain volume best predicted performance across species and accounted for considerably more variance than brain volume controlling for body mass. This result corroborates recent advances in evolutionary neurobiology and illustrates the cognitive consequences of cortical reorganization through increases in brain volume. Within primates, dietary breadth but not social group size was a strong predictor of species differences in self-control. Our results implicate robust evolutionary relationships between dietary breadth, absolute brain volume, and self-control. These findings provide a significant first step toward quantifying the primate cognitive phenome and explaining the process of cognitive evolution.
View details for DOI 10.1073/pnas.1323533111
View details for PubMedID 24753565
- Predictors of Achievement When Virtual Manipulatives are Used for Mathematics Instruction REDIMAT-REVISTA DE INVESTIGACION EN DIDACTICA DE LAS MATEMATICAS 2014; 3 (2): 121-+
The impact of emotion on numerosity estimation
FRONTIERS IN PSYCHOLOGY
Both time and numerosity can be represented continuously as analog properties whose discrimination conforms to Weber's Law, suggesting that the two properties may be represented similarly. Recent research suggests that the representation of time is influenced by the presence of emotional stimuli. If time and numerosity share a common cognitive representation, it follows that a similar relationship may exist between emotional stimuli and the representation of numerosity. Here, we provide evidence that emotional stimuli significantly affect humans' estimation of visual numerosity. During a numerical bisection task, enumeration of emotional stimuli (angry faces) was more accurate compared to enumeration of neutrally valenced stimuli (neutral faces), demonstrating that emotional stimuli affect humans' visual representation of numerosity as previously demonstrated for time. These results inform and broaden our understanding of the effect of negative emotional stimuli on psychophysical discriminations of quantity.
View details for DOI 10.3389/fpsyg.2013.00521
View details for Web of Science ID 000331187700001
View details for PubMedID 23950754
- A study comparing virtual manipulatives with other instructional treatments in third- and fourth-grade glassrooms Journal of Education 2013; 193 (2): 25-39
A shared system of representation governing quantity discrimination in canids.
Frontiers in psychology
2012; 3: 387-?
One way to investigate the evolution of cognition is to compare the abilities of phylogenetically related species. The domestic dog (Canis lupus familiaris), for example, still shares cognitive abilities with the coyote (Canis latrans). Both of these canids possess the ability to make psychophysical "less/more" discriminations of food based on quantity. Like many other species including humans, this ability is mediated by Weber's Law: discrimination of continuous quantities is dependent on the ratio between the two quantities. As two simultaneously presented quantities of food become more similar, choice of the large or small option becomes random in both dogs and coyotes. It remains unknown, however, whether these closely related species within the same family - one domesticated, and one wild - make such quantitative comparisons with comparable accuracy. Has domestication honed or diminished this quantitative ability? Might different selective and ecological pressures facing coyotes drive them to be more or less able to accurately represent and discriminate food quantity than domesticated dogs? This study is an effort to elucidate this question concerning the evolution of non-verbal quantitative cognition. Here, we tested the quantitative discrimination ability of 16 domesticated dogs. Each animal was given nine trials in which two different quantities of food were simultaneously displayed to them. The domesticated dogs' performance on this task was then compared directly to the data from 16 coyotes' performance on this same task reported by Baker et al. (2011). The quantitative discrimination abilities between the two species were strikingly similar. Domesticated dogs demonstrated similar quantitative sensitivity as coyotes, suggesting that domestication may not have significantly altered the psychophysical discrimination abilities of canids. Instead, this study provides further evidence for similar non-verbal quantitative abilities across multiple species.
View details for DOI 10.3389/fpsyg.2012.00387
View details for PubMedID 23060847
Tracking of food quantity by coyotes (Canis latrans)
2011; 88 (2): 72-75
Previous studies have demonstrated that Weber's Law mediates quantitative discrimination abilities across various species. Here, we tested coyotes' (Canis latrans) ability to discriminate between various quantities of food and investigated whether this ability conforms to predictions of Weber's Law. We demonstrate herein that coyotes are capable of reliably discriminating large versus small quantities of discrete food items. As predicted by Weber's Law, coyotes' quantitative discrimination abilities are mediated by the ratio between the large and small quantities of food and exhibit scalar variability. Furthermore, in this task coyotes were not discriminating large versus small quantities based on olfactory cues alone.
View details for DOI 10.1016/j.beproc.2011.08.006
View details for Web of Science ID 000295996700002
View details for PubMedID 21856389
Multisensory information boosts numerical matching abilities in young children
2011; 14 (2): 205-213
This study presents the first evidence that preschool children perform more accurately in a numerical matching task when given multisensory rather than unisensory information about number. Three- to 5-year-old children learned to play a numerical matching game on a touchscreen computer, which asked them to match a sample numerosity with a numerically equivalent choice numerosity. Samples consisted of a series of visual squares on some trials, a series of auditory tones on other trials, and synchronized squares and tones on still other trials. Children performed at chance on this matching task when provided with either type of unisensory sample, but improved significantly when provided with multisensory samples. There was no speed–accuracy tradeoff between unisensory and multisensory trial types. Thus, these findings suggest that intersensory redundancy may improve young children’s abilities to match numerosities.
View details for DOI 10.1111/j.1467-7687.2010.00966.x
View details for Web of Science ID 000287489500005
View details for PubMedID 22213895