Uncovering pathophysiological mechanisms of psychosis using the oculomotor system

A subset of the symptoms of schizophrenia can be characterized by a failure in attributing actions to oneself, or a loss of agency (e.g. delusions that one is being controlled by aliens, attributing thoughts or subvocalizations externally). The aim of this project is to investigate the a potential sensorimotor mechanism thought to support a subjective sense of agency in schizophrenia patients at different illness stages and in individuals with bipolar disorder by using eye movements as a tool. Understanding the precise mechanisms, developmental profile, and diagnostic specificity of agency disturbances in schizophrenia can bring us closer to more targeted interventions and lead to more specific methods for early identification.

Investigating short-term plasticity in schizophrenia using visual adaptation

Abnormalities in synaptic plasticity are argued to underlie the robust functional dysconnectivity observed in schizophrenia. One functional manifestation of short-term neural plasticity is sensory adaptation, whereby sensory neurons exhibit reduced sensitivity after sustained stimulus exposure. Adaptation can be measured precisely and non-invasively in the visual system using a class of illusory percepts termed visual aftereffects. In the current project, we are measuring the strength of these visual aftereffects, which have been referred to as the “psychophysicist’s microelectrode” because these aftereffects can be traced back to adaptation of specific neural populations. Accordingly, findings from this project may shed light on disease mechanisms as well as on the cause of perceptual changes in schizophrenia.