1980-84 UBC, M.D.
1987-90 UBC, Neurology
1990-91 University of Iowa, Neuro-ophthalmology
1991-95 University of Toronto, Neuro-ophthalmology, Ph.D
Our laboratory has studied a variety of perceptual phenomena in patients with cerebral lesions. These include studies on motion perception, blindsight, neglect, and alexia, for example. Our major focus at present and for the last five years, though, has been on faces.
Face identification is one of the most challenging tasks our perceptual system faces. All faces share a basic shape, and only subtle variations distinguish one from another. Despite this, we identify each other with ease on a daily basis, often with a single glance, sometimes after long periods of separation. Understanding how we do this can give us insights into the workings of sophisticated levels of object recognition.
One classic approach to studying face recognition is to use the paradigm of the inverted face. Current thinking is that our ability to distinguish one face from another is acquired through years of exposure and interest in early childhood. Because the most faces we see during this 'training' period are upright, the expertise we gain is orientation-specific. Contrasting perceptual skills during processing of upright faces with those during processing of inverted faces should reveal something about the nature of expert face processing mechanisms.
A neuropsychological approach can also provide data. Prosopagnosia is a rare condition with a selective absence of the ability to recognize faces. There are developmental forms, some of which are inherited, and acquired forms, in which face recognition is lost from strokes, head injuries, or tumours. Our laboratory has been studying the perceptual deficits in a series of prosopagnosic patients, in particular those with lesions involving the fusiform face area. (This face processing region on the inferior occipital cortex was identified by functional magnetic resonance imaging studies.) We have used perceptual and imagery tests to make correlations between structural damage and functional deficits within these prosopagnosics.
While prosopagnosia is a rare syndrome, the data from these patients are also relevant to other more common conditions. For example, there may be a link between impaired face perception and social developmental disorders such as autism and Asperger disorder. Some suggest that impaired face perception impedes the developmental of normal social interactions. Others suggest that socially impaired individuals lack the interest in faces that promotes development of perceptual expertise. Our early investigations of subjects with social developmental disorders show perceptual heterogeneity. Some subjects clearly have no problem recognizing faces, while others do, though in general these subjects are not as badly impaired in face recognition as prosopagnosic patients. This raises a lot of questions. Do those with perceptual dysfunction have a fundamentally different disorder than those who do not? If so, what does this mean for genetic and therapeutic studies of these patients?
Eye movements are an elegant way to study how we interact with our environment. They are simple in their mechanics and can be precisely measured in both space and time by inexpensive devices. Conceptually, our understanding of ocular motor circuitry in animal models is more advanced than that of other response systems. Also, for most of us the exploration of the world is primarily a visual one. Understanding eye movements helps us understand human experience.
We can study eye movements for different reasons and at different neural levels, rangin from muscle to brain. Our laboratory focuses on cerebral and cognitive aspects of ocular motor function.
We are interested in what saccades tell us about voluntary control. We study prosaccades (look at a target that appears off to one side) and antisaccades (do the un-natural thing, look in the other direction). When these are mixed together in the same block, we can study 'historical' effects. What sorts of influence do prior trials have on future ones? What are the behavioural signatures of the various cognitive processes involved in manufacturing different sequences of trials? Saccades are a simple yet precise tool that can isolate the contributions of processes such as set prediction, active reconfiguration processes, and plastic changes in the saccadic system that persist from one trial to the next.
In addition to studying these in healthy subjects, we are using the same paradigms to learn about response control in schizophrenia. In collaboration with Dara Manoach at Massachusetts General Hospital, we are using fMRI and MEG to study the human physiology and anatomy of these processes.
The fovea has the finest spatial resolution of our visual map. To perceive visual detail, we need to place the fovea accurately on a region of interest. When we look at objects and scenes, we characteristically make a series of saccades that shift our fixations to different locations of the stimulus. These saccades and fixations take time and effort, but are probably important elements of a dynamic, interactive process that formulates perceptual hypotheses and aims at a threshold that will trigger a perceptual decision. To understand scanning patterns one has to understand not only the stimulus but the goal of the observer approaching the stimulus. We can examine scanning patterns for a number of observer effects. How does the type of task influence scanning patterns, even for identical stimuli? What about perceptual expertise - does historically-acquired skill in making perceptual distinctions translate to more efficient scanning patterns for information gathering? How does prior exposure alter scanning patterns, and what does this tell us about internal representations of objects?
109. Scheel M, Abegg M, Lanyon LJ, Mattman A, Barton JJS. Eye movement and diffusion tensor imaging analysis of treatment effects in a Niemann Pick Type C patient. Mol Genet Metab 2010; 99: 291-5.
110. Lee H, Abegg M, Rodriguez A, Koehn JD, Barton JJS. Why do subjects make antisaccade errors? Exp Brain Res 2010; 201: 65-73.
111. Rodriguez A, Barton JJS. Clinical reasoning: An unusual pattern of optic disc swelling and visual loss. Neurology 2010; 74; e43-6.
112. Iaria G, Fox, CJ, Scheel M, Stowe RM, Barton JJS. A case of persistent visual hallucinations of faces following LSD abuse: a functional magnetic resonance imaging study. Neurocase 2010; 16: 106-18.
113. Dalrymple KA, Bischof W, Cameron D, Barton JJS, Kingstone A. Simulating simultanagnosia: spatially constricted vision mimics the phenomenon of local capture. Exp Brain Res 2010; 202: 445-55.
114. Mitra AR, Abegg M, Viswanathan J, Barton JJS. Line bisection in simulated homonymous hemianopia. Neuropsychologia 2010; 48: 1742-9.
115. Barton JJS, Fox CJ, Sekunova A, Iaria G. Encoding in the visual word form area: an fMRI-adaptation study of words versus handwriting. J Cogn Neurosci 2010; 22: 1649-61.
116. Abegg M, Rodriguez AR, Lee H, Barton JJS. ‘Alternate-goal bias’ in antisaccades and the influence of expectation. Exp Brain Res 2010; 203: 553-62.
117. Agam Y, Joseph RM, Barton JJ, Manoach DS. Reduced cognitive control of response inhibition by the anterior cingulate cortex in autism spectrum disorders. Neuroimage 2010; 52: 336-47.
118. van der Stigchel S, Nijboer TCW, Bergsma DP, Abegg M, Barton JJS. Anomalous global effects induced by ‘blind’ distractors in visual hemifield defects. Brain Cognition 2010; 74: 66-73.
119. Oruc I, Barton JJS. A novel face aftereffect based on recognition contrast thresholds. Vision Res 2010; 50:1845-54
120. Barton JJS, Maguire J, Mezei M, Briemberg HR. Mitochondrial pseudo-myasthenia. J Neuroophthalmol 2010; 30: 248-51.
121. Abegg M, Lee H, Barton JJS. Systematic diagonal and vertical errors in antisaccades and memory-guided saccades. J Eye Mov Res 2010; 3(3):5, 1-10.
122. Oruc I, Barton JJS. Critical frequencies in the perception of letters, faces, and novel shapes: evidence for limited scale-invariance for faces. J Vision 2010; 10(12):20, 1-12.
123. Barton JJS, Sekunova A, Sheldon C, Johnston S, Iaria G, Scheel M. Reading words, seeing style: The neuropsychology of word, font and handwriting perception. Neuropsychologia 2010; 48: 3868-77.
124. Dalrymple KA, Bischof W, Cameron D, Barton JJS, Kingstone A. Experiencing simultanagnosia through windowed viewing of complex social scenes. Brain Res 2011; 1367: 265-77.
125. Abegg M, Manoach DS, Barton JJS. Knowing the future: partial foreknowledge effects on the programming of prosaccades and antisaccades. Vision Res 2011; 51: 215-21.
126. Lee AKC, Hamalainen MS, Dyckman KA, Barton JJ, Manoach DS. Saccadic preparation in frontal eye field is modulated by distinct trial history effects as revealed by magnetoencephalography. Cerebral Cortex 2011; 21: 245-53.
127. Oruc I, Guo XM, Barton JJS. Gender in facial representations: a contrast-based study of adaptation within and between the sexes. PLoSONE 2011; 6: e16251.
128. Pfeffer G, Abegg M, Vertinsky AT, Ceccherini I, Caroli F, Barton JJS. The ocular motor features of adult-onset Alexander disease: a case and review of the literature. J Neuroophthalmol 2011; 31: 155-9.
129. Dalrymple KA, Birmingham E, Bischof W, Barton JJS, Kingstone A. Opening a window on attention: Documenting and simulating recovery from simultanagnosia. Cortex 2011; 47: 787-99.
130. Foulsham T, Barton JJS, Kingstone A, Dewhurst R, Underwood G. Modeling eye movements in visual agnosia with a saliency map approach: bottom-up guidance or top-down strategy? Neural Networks 2011; 24: 665-77.
131. Simpson S, Abegg M, Barton JJS. Rapid adaptation of visual search in simulated hemianopia. Cerebral Cortex 2011; 21: 1593-601.
132. Dalrymple KA Oruc I, Duchaine B, Fox CJ, Iaria G, Handy TC, Barton JJS. The neuroanatomic basis of the face-selective N170 in acquired prosopagnosia: a combined ERP/fMRI study. Neuropsychologia 2011; 49: 2553-63.
133. Oruc I, Barton JJS. Adaptation improves face identity discrimination. Proc Roy Soc Lond B Biol Sci 2011; 278: 2591-2597.
Assistant-Associate Professor of Neurology, Harvard Medical School
Director, Neuro-ophthalmology Clinic, Beth Israel Deaconess Medical Center
Director, Human Vision and Eye Movement Laboratory, Harvard Medical School
Director, Neuro-ophthalmology Section, UBC
1995 Francis McNaughton Award, Canadian Congress of Neurological Sciences
1998 Young Investigator Award, North American Neuro-ophthalmology Society
1999 Outstanding Teacher Award, Harvard Longwood Neurology residency
2003 Outstanding Teacher Award, Harvard/Beth-Israel Deaconess Medical Center Neurology residency
2004 Canada Research Chair
2004 Michael Smith Foundation for Health Research Senior Scholarship
2005 Norman Geschwind Prize for Behavioural Neurology, American Academy of Neurology