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Using Studies of Human Perception and Cognition to Investigate the Neurobiological Underpinnings of Schizophrenia-Spectrum Disorders

Hosted by: Professor Ehsan Arabzadeh

Abstract

Traditionally, the cortical dysfunction associated with Schizophrenia-Spectrum Disorders (SSD) has been conceptualised within neuropsychological models of acquired brain lesions. However, the developmental nature, widespread cellular pathology, and absence of macroscopic lesions characterising these disorders argues for alternative approaches, such as evolutionary neurobiology. The Dual Cytoarchitectonic Trends model suggests that mammalian cortex has expanded and elaborated across phylogeny along two large-scale, parallel anatomic trends. The cortical regions constituting these trends can be subdivided by cytoarchitecture, anatomy and function and are well-instantiated by the dorsal and ventral visual processing streams and anterior attention systems. The current studies hypothesized that SSD are disproportionately associated with impairment in cortical regions of the dorsal steams/systems. Here, this hypothesis is explored using visual psychophysical, reach-to-grasp motor control, visual search, and directed forgetting paradigms. In all cases, the behavioural results support exaggerated impaired dorsal stream/system processing. More recent research has turned toward explorations of the potential physiological anomalies connecting the hypothesized cortical processing deficits to psychotic symptoms. Specifically, Bayesian perception posits that perceptual experience arises as a multiplicative function between observers’ expectations and the quality of their sensory evidence. In the wake of poor-quality sensory evidence, observers may unduly rely on expectation, thereby generating perceptual errors such as hallucinations. The overall empirical and clinical implications of this research is also discussed.

Biography

Professor Bruce Christensen completed his undergraduate degree in biopsychology at the University of British Columbia before attending Vanderbilt University for a PhD in both cognitive neuroscience and clinical psychology. He then enrolled in an APA-approved internship in clinical neuropsychology at the Long Island Jewish Medical Centre, part of the Albert Einstein College of Medicine in New York City, before completing a postdoctoral fellowship in cognitive neuroscience and clinical neuropsychology at the Rotman Research Institute, University of Toronto. Bruce is currently a Professor, Deputy Director, and Head of Psychology in the School of Medicine and Psychology at the ANU. Previously, he has held research-clinical faculty positions at the University of Toronto and McMaster University where he directed clinical psychological assessment services and established cognitive neuroscience laboratories investigating the cognitive and neurobiological mechanisms of serious mental illness. He also has served as the Associate Dean (Culture and Wellbeing) CHM, Director of the Clinical Psychology Program ANU, Director of the Research School of Psychology ANU, and the Vice Chair for Healthy Minds Canada. Bruce has been awarded visiting scholar fellowships to the University of Cambridge and Durham University. He has also won several teaching and supervision awards and team/program awards for the Clinical Psychology program and previous clinical services.