Simon M. McCrea, Ph.D.
Research Biography
Biography and Research Interests
I began my initial undergraduate university program in a course of pre-medical studies in biochemistry at the University of Saskatchewan in 1986. I then completed an Honours certificate post-degree program in Psychology also from the University of Saskatchewan. I then spent several summers working in a neurology laboratory. These studies involved the measurement of brain metabolites using the technique of in-vivo microdialysis in conjunction with high performance liquid chromatography. I also developed some expertise testing animals on various neurobehavioural mazes for the correlation of brain-behavior relationships. Incidentally it was about this time that I read my first neuropsychology book -- Dawson and Fischer's "Human behavior and the developing brain" (1994). The combination of actual first-hand experience in designing, analyzing, and publishing experimental neurology research on my own spurred my interest in going to graduate school.
In part because I enjoyed research as well as interacting with people I then decided to work with Dr. John Mueller of Applied Psychology in the Faculty of Education at the University of Calgary. Dr. Mueller is a noted cognitive psychologist and expert on the effects of anxiety on human performance. Together we developed research partnerships with clinical neuropsychologists at Foothills Hospital in Calgary. At that time I was very interested in cognitive psychology, neuropsychology as these relate to educational matters in addition to enrolling in clinical course-work. About this time I fondly recall reading Kolb and Whishaw's (1996) "Fundamentals of human neuropsychology." This well-written introductory textbook in human neuropsychology provided some of the impetus for my Master of Science thesis completed at the University of Calgary.
In collaboration with Research Services of Calgary Public and Separate School systems I assessed approximately one hundred and thirty students with a brief neuropsychological selection of tests. This Masters work pertained to the development of executive functions (e.g., strategy, planning, goal-setting and working memory) in young children. In this thesis it was found that formal education had moderate effects on the development of these self-regulatory aspects of cognition -- dependent on the type of task. This study used the cut-off design in which students with birth dates just before and after the school entrance cut-off are compared. With this unique design both brain maturation and schooling per se can be accurately compared. After earning my Master of Science degree at the University of Calgary this study was subsequently published in the international journal Child Neuropsychology.
Towards the end of my Masters program I became more interested in clinical aspects of neuro-psychology and was thrilled to be accepted into a doctoral program at the University of Alberta's Department of Educational Psychology. I was awarded a full doctoral scholarship and shortly thereafter in Edmonton my daughter Zanna was born. My supervisor was Dr. J.P. Das, an eminent researcher with interests in individual differences and verbal learning and the co-author with Dr. Jack Naglieri of the newly released "Das-Naglieri Cognitive Assessment System" (1997). About this same time as luck would have it a former supervisor of mine (Dr. Ashfaq Shuaib) had relocated from George Washington University Medical Center to the University of Alberta to head the neurology department's stroke program there.
I began a validity study of the neuropsychological properties of the Cognitive Assessment System in a relatively small sample of cerebrovascular disease patients. This work was carried out under the dual supervision of Dr. Thomas Snyder of the University of Alberta Hospital's Neuropsychology Department and Dr. Robert Ashforth with the Department of Neuroradiology. I graduated with my doctorate in the fall of 2001. Completion of this validity study on this unique psychometric instrument has resulted in publications in Brain and Cognition, Archives of Clinical Neuropsychology, Applied Neuropsychology, International Journal of Neuroscience and more recently in Psychology Research and Behavioral Management. In the last two years further studies by a Japanese research group has examined the use of some of the Das-Naglieri Cognitive Assessment System subtests in functional neuroimaging environments and contexts.
I then started a post-doctoral fellowship in the summer of 2001 after being awarded a National Science and Engineering Research Council of Canada grant in the spring. I started studying the development of white matter or the wiring of the brain in children, adolescents, and adults at the Department of Biomedical Engineering at the University of Alberta. White matter tracts are the neural fibers in the brain that conduct nerve impulses and recently it has been shown that individual differences in these tracts can lead to changes or modifications in cognitive modules in the brain. In conjunction with faculty in the Department of Biomedical Engineering we began studies using various experimental techniques in magnetic resonance imaging (MRI).
At the Department of Biomedical Engineering in addition to learning about the basics of pulse-sequence programming and operation of the MRI scanners I began some new post-graduate studies in functional neuroimaging. It was here that I had some initial experiences of designing and conducting experiments using functional magnetic resonance imaging (fMRI) and diffusion tensor imaging. In conjunction with Dr. Chris Westbury of the Department of Psychology of the University of Alberta and Dr. Jeffrey Binder of the Department of Neurology at the Medical College of Wisconsin we examined the neural architecture associated with grasping and non-grasping verbs within the anterior intraparietal sulcus.The intraparietal sulcus within the anterior-superior parietal lobule has been shown to possess "mirror neurons" in both monkeys and man. Mirror neurons are neurons that activate when an actor performs an action or another observed person performs that same action.
Mirror neurons' discovery a little over a decade ago has been described as one of the most important discoveries in the cognitive neurosciences. It is hypothesized that mirror neurons may underlie many aspects of complex social cognition. In the fall of 2001 I along with Morgan Willson, P.Eng, MD designed and completed the analysis of a functional neuroimaging study of the neural representation of body parts using a full-scale model of a mannequin. These studies have resulted in publications in Behavioral Brain Research and Brain and Cognition. The functional magnetic resonance imaging study of human body parts used the well-studied face recognition and face encoding conditions as standard comparison tasks. Our study was among the very first functional neuroimaging studies to be completed at the University of Alberta’s Peter S. Allen MR Research Center.
In November of 2004 I began a National Institute of Health (NIH)-funded post-doctoral fellowship with Dr. Branch Coslett at the Department of Cognitive Neurology at the University of Pennsylvania. Dr. Coslett is a expert on cognitive neurology and cognitive neuropsychology. We began an interesting program of integrated studies examining: (i) sound localization in patients with left or right hemisphere strokes, as well as; (ii) conducting single case studies of a patient with Balint's
syndrome. This study is among the most comprehensive of this rare disorder in the published literature. Balint's syndrome is a neurological illness comprising the triad of (i) ocular apraxia, (ii) optic ataxia and (iii) simultanagnosia. Oculomotor apraxia is one of a number of closely related phenomenon which has sometimes been provocatively referred to as "psychic paralysis of gaze". Such patients are unable to shift gaze voluntarily from the point of fixation, and stimuli appearing peripherally fail to engage visual attention. Optic ataxia in contrast is a failure to reach under visual guidance whereas simultanagnosia is a perceptual and cognitive disorder in which the patient cannot perceive more than one object at the same time.
Simultanagnosia in particular was first studied in depth by the famous Russian neurologist Alexander Luria in Soviet soldiers injured by gunshot wounds during World War II. Luria is generally credited as one of the forerunners of the field of neuropsychology using his extensive elaboration of many clinical neurological examination procedures as well as qualitative analysis of many such experimental tests that he devised. His study of simultanagnosic patients with bilateral lesions of the superior occipitoparietal cortex in part resulted in his elucidation of a theory about ubiquitous "simultaneous" and "successive" cognitive processes in the human brain. Incidentally Luria's theories about these dual cognitive processes were adapted by Das and colleagues and resulted in Das, Kirby and Jarman's elaboration and eventual publication of their influential theory of "Simultaneous and successive cognitive processes" in 1979 using cross-cultural and factor analytic studies.
The simultanagnosic patient (ED) studied at the University of Pennsylvania was examined with a variety of cognitive neuropsychological tests. We found that ED's ability to recognize scrambled word strings was proportional to the distance between the individual letters. In other words the object recognition systems were compensating for damaged dorsal stream visual attentional systems allowing for the patient to encode meaning of word fragments some distance apart. Aside from the interesting theoretical implications of the interaction of object recognition and semantic systems simultanagnosia was historically important in understanding the distinction between dorsal visual attention and ventral object recognition systems. The dorsal and ventral stream theory of consciousness, in the overarching sense, was first fully elaborated upon by Milner and Goodale in their influential 1995 text - "The Visual Brain in Action". Our study also had some interesting implications for understanding human individual differences in healthy normal subjects, if for instance, one or the other ventral or dorsal streams is disproportionately developed via white matter connectivity in humans. These studies with Dr. Coslett and Dr. Laurel Buxbaum resulted in publications in Neuropsychologia and Experimental Brain Research.
Right after completing this post-doctoral fellowship at the University of Pennsylvania I started a National Institute of Mental Health (NIMH)-funded post-doctoral fellowship at the University of British Columbia to study with Dr. Jason Barton. Dr. Barton is an expert on face recognition and ventral stream cortical functions as well as being recently appointed a Canada Research Chair in Neuropsychology. At Vancouver General Hospital I began to amalgamate some of my ideas about the functioning of the dorsal visual attentional system began at the University of Pennsylvania with current theoretical notions about the essential processes occurring in the ventral objection recognition system. One of these ideas is simply of inverse cognitive modeling meaning that multiple sightings of "where" can lead to the elucidation or more likely inference of an object's identity or "what" it is. Conversely, many different chance encounters with objects and their associated qualitative features in the world can lead to the inference of a specific location or source of signal through triangulation.
At the University of British Columbia I was encouraged to read widely about the perceptual processes involved in object recognition as well as learning about the functions of the most rostral ends of the termination of the ventral stream - the orbitofrontal cortex. While I was a fellow at the University of British Columbia I spent a considerable effort reading through some essential texts on the interaction of these two systems in the human brain. I also began to formulate some hypotheses about the functioning of various neuropsychiatric neural systems involved in common mental illnesses. This research culminated in my development of a theory about the functioning and interaction of these two systems in bipolar disorder - a common mood disorder affecting many people. This research was published as a lengthy review in Neuropsychiatric Disease and Treatment which is the the official journal of the International Neuropsychiatric Association. This research also builds on some recent ideas about the neurological basis of individual differences advocated by Dr. Kenneth Heilman in his popular "Creativity and the brain" (2005) as well as older compilations such as "Right hemisphere language comprehension" (1998) contributed by his students such as Dr. Branch Coslett.
Since completing post-doctoral work at the University of British Columbia in Vancouver in the summer of 2007 I have been working on a number of areas including licensure as a clinical and experimental neuropsychologist. I have also been continuing to do some research work on intuition, insight, and right hemispheric functions in humans. There is some good anecdotal evidence as well as published case reports that individuals with strongly lateralized right hemipheric functions could possibly develop anomalous sociocognitive functions as a result of unusual co-localization of cognitive functions within a hemisphere. This is hypothesized to potentialy occur through development when there is a critical threshold of neural plasticity in the form of fluid intelligence to amalgamate one or more cognitive modules within a hemisphere. This "co-localization hypothesis" was first postulated by two independent research groups of experimental neuropsychologists working separately in Milan and Boston in the mid-1980's. Specifically it has been hypothesized that unusual modules within a hemisphere could ontogeneticaly result in anomalous functions that would not be readily explainable on the basis of hypothesized "normal" functions in a presumably normal language dominant left hemisphere.
Two candidates for such melding would be language and spatial functions that might be capable of fusing into an "inverse cognitive modeling" mechanism. It is hypothesized that such a mechanism would allow for the generation of a much more abstract and articulate lexicon of visual gestures. This might also explain some evidence showing better developed intuitive and insightful functions in strongly right hemisphere language lateralized subjects. Moreover previously published studies of such individuals have shown that women tend to outnumber men as well as demonstrating better nonverbal decoding mechanisms than men. Hence an essential nonverbal decoding basis to the these anomalous functions is proposed. Also some data suggests that such subjects often achieve beyond what might be expected based on traditional measured intelligence. Enhanced social or emotional intelligence and/or tacit knowledge might explain such findings. This research is being published as a review in Psychology Research and Behavioral Management in February of 2010.
