SU25. Lack of Pupillary Modulation by Antisaccade Performance in Schizophrenia, Schizoaffective Disorder, and Psychotic Bipolar Disorder Suggests Reduced Top-Down Control During Response Preparation on an Executive Control Task

Abstract

Background: Pupil dilation, a measure of physiological arousal, is associated with increased cognitive demand (Moresi et al, 2008) and response preparation in the antisaccade task. Greater change in pupil size during the preparatory period prior to saccade generation for correctly performed antisaccade trials vs prosaccade errors has been observed among healthy controls, perhaps reflecting inhibitory input from the frontal eye fields (FEF) and superior colliculus (SC) to brainstem regions responsible for saccade generation (Wang et al, 2015). The relationship between pupillary response and antisaccade performance in individuals across the psychosis spectrum is less established. Our objective was to examine differences in the relationship between changes in pupil size during the preparatory period and antisaccade performance in individuals across the psychosis spectrum and healthy controls. Methods: Individuals with schizophrenia (n = 47), schizoaffective disorder (n = 31), psychotic bipolar disorder (n = 67), and controls (n = 68) from the Chicago site of the Bipolar Schizophrenia Network on Intermediate Phenotype (BSNIP) study completed an antisaccade task, in which they were to inhibit the response to look to a target and generate an eye movement in the opposite direction. Percent change in pupil size from baseline during the 700-ms preparatory period prior to target appearance was measured for correct and incorrect antisaccade performance and compared across patient and control groups. Results: As reported previously (Reilly et al, 2015), patient groups had increased antisaccade error rate compared to controls, and this effect was greatest among schizophrenia and schizoaffective groups followed by the psychotic bipolar disorder group. Linear mixed-effects models revealed a greater increase in pupil size over the preparatory period for correct antisaccade trials compared to incorrect trials among healthy controls (P ≤ .001); this modulation of pupillary response and antisaccade performance was not observed among the patient groups (P’s > .9). Changes in pupillary response during the preparatory period were not related to current daily antipsychotic medication dose or current exposure among patient groups. Conclusion: Pupil size was modulated by antisaccade performance in healthy controls, such that greater pupil size in preparation for intact antisaccade performance compared to incorrect performance was observed. This relationship was not maintained in individuals with schizophrenia, schizoaffective disorder, or psychotic bipolar disorder. These findings suggest that reduced top-down control during the response preparation period, perhaps from FEF inputs to the SC, contributes to the deficits in executive control as assessed by the antisaccade task across the psychosis spectrum. Furthermore, these data provide support for pupillometry as a useful index of top-down control in cognitive tasks.