M.D., University of Toronto
My research focuses on elucidating the architecture and dynamics of cognitive control mechanisms and how they are disturbed in serious mental illness such as schizophrenia. Cognitive control describes the ability to coordinate and appropriately bias cognitive processes in the service of goal-directed behavior. One line of my research investigates how the top-down influences are dynamically adjusted in response to the influences of stimulus and response history, changes in attentional state, and updates in task demands. A useful way of investigating the dynamics of these responses is to examine trial-to-trial adjustments. For instance, trials that incur processing conflict are known to elicit control adjustments on subsequent trials. We examine such adjustments using conflict and task-switching behavioral paradigms during EEG and fMRI acquisition to examine the brain areas and dynamics underlying these adjustments, and employ computational models to characterize and make predictions concerning our results.
Another related line of my research examines the role of synchronous, oscillatory neuronal activity in supporting cognitive control processes. Gamma-band oscillations have been associated with basic perception as well as higher-order cognitive processes such as attention and working memory. My research investigates the importance of synchronous oscillations to cognitive control processes such as the maintenance of task context information. We use EEG during behavioral paradigms to probe such associations and have begun computational modeling studies to understand the mechanisms by which oscillations may help in supporting the appropriate representations.
My research in normal cognition is also applied to understanding the disturbances in cognitive control in schizophrenia. We have ongoing behavioral, EEG and fMRI studies in schizophrenia, including studies of medication-naïve, first-episode schizophrenia patients, offering the unique opportunity to examine disturbances in cognition in the absence of such important confounds as medication effects and treatment chronicity. Employing our computational models of normal cognition, we are also exploring the consequences of principled ‘lesions’ to the models to shed light on the specific pathophysiologic processes that give rise to the cognitive impairments in schizophrenia.