Jose Reynoso^1,2,3, Diana Freed^1,2,3, Maya Glasman^1,3, Brian P. Keane^1,2,3, Duje Tadin^1,2,3; ¹University of Rochester, ²University of Rochester Medical Center, ³Center for Visual Science

Vision is inherently noisy. This noise principally arises from external properties of stimuli (external noise) and brain activity unique to each individual (internal noise). There is growing evidence that increases in internal noise are linked to natural changes like aging (Bogfjellmo, 2013) as well as to psychiatric and neurological conditions (Wolff, 2022). This includes schizophrenia, where increased internal noise might help explain perceptual and cognitive deficits. Here, we assessed internal noise using a double pass technique and hypothesized that people with schizophrenia would show higher levels of internal noise compared to healthy controls. To test this, we recruited 21 healthy controls and 21 schizophrenia patients to complete an orientation discrimination task using virtual reality, with data collection ongoing. In the double pass technique, subjects saw repeated instances of noisy and/or ambiguous stimuli. A noise-free observer will provide the same response to repeated instances of identical stimuli, regardless of a correct response. As internal noise increases, so does the likelihood that responses to repeated instances of identical stimuli will differ. In our study, subjects were shown 201 unique, noisy Gabor patches twice and tasked to verbally report the orientation of the signal grating (left or right). After 67 trials, subjects were shown a second pass of the previous 67 stimuli (402 trials total). Internal noise was estimated based on consistency of responses to repeated stimuli with a correction for baseline accuracy. Our preliminary results revealed marginally elevated internal noise in patients compared to controls (p=0.07, Cohen's d=0.57), reflecting less consistent responses across repeated stimuli (p=0.02, Cohen’s d=0.74). Patients also had lower task accuracy (p=0.02, Cohen’s d=0.75). We are currently investigating whether elevated internal noise can explain deficits in visual working memory as well as proprioception- and vision-guided reaching, potentially offering insight to how internal noise may affect perceptual and cognitive function.