The overall aim of this research program is to use psychometric, psychophysical, and electrophysiological techniques to characterize visual processing deficits in schizophrenia spectrum disorders. The model motivating this project proposes that patients with schizophrenia (SZ), but not subjects with schizotypal personality disorder (SPD), will demonstrate disturbances of early stage vision and visual event related potentials (ERP) indicative of retino-geniculate or occipital cortex disturbances. Moreover, these disturbances appear to be most profound for stimuli and tasks requiring high temporal resolution or integration, suggestive of disturbed neural synchronization. Because neural synchronization at high firing frequencies may be essential for spatial and temporal binding or integration, this deficit could account for a broad range of disturbances in SZ. The model also suggests that working memory deficits are a core feature of both schizophrenia and SPD, which reflect disrupted frontal lobe function. Discrimination and delayed match-to-sample tests of short-term visual memory will be used to test these behavioral hypotheses. Event-related potential paradigms will be used to assess sensory processes, EEG synchronization to periodic stimulation, sensory gating, and attention and working memory operations. Computational modeling of neural circuits will be used to assess the role of NMDA and nicotinic dysregulation in producing these deficits. These findings may provide evidence regarding how schizophrenia and SPD differentially affect early stage vision and memory operations; implicate specific visual pathways and circuits which may be differentially sensitive to neurodevelopmental insults; and indicate visual processing deficits can identify core features across schizophrenia spectrum disorders.
Showing the most recent 10 out of 36 publications
