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28. Diagnostic Specificity of Oculomotor Corollary Discharge Abnormalities in Schizophrenia
Corollary discharge (CD) signals are “copies” of motor signals sent to sensory areas to predict the corresponding input. Because they are used to distinguish actions generated by oneself versus external forces, altered CD is a hypothesized mechanism for the agency disturbances that characterize psychosis. Supporting this notion, previous studies have revealed that schizophrenia patients are characterized by a decreased influence of CD signals on visual perception around the time of an eye movement, and the extent of this impairment is related to the degree of psychotic symptoms. These results suggest that the relationship between CD and psychosis might reflect a trans-diagnostic proneness to psychosis. Here, we studied three groups of participants: Schizophrenia or Schizoaffective Disorder (SZP), Bipolar Disorder with a history of psychosis (BP), and healthy controls (HC) while they performed the blanking task, a task that measures the influence of CD on visual perception following a saccade. Multi-level modeling was used to examine the degree to which participants use eye gaze location instead of a CD signal to make visual judgments. In addition, CD measures were related to clinical symptom severity. Data collection is ongoing and analyses are underway. We will discuss these results in the context of their implications for understanding the relationship between altered saccadic CD and psychosis across narrow diagnostic boundaries.