Visual Processing in Schizophrenia

Nathan S. Kline Institute For Psych Res, Orangeburg NY

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Abstract

DESCRIPTION (provided by applicant): Sensory processing deficits constitute a central feature of schizophrenia. This project will investigate the basis of visual pathway dysfunction in schizophrenia using complementary neurophysiological and psychophysical measures and MRI. Neurocognitive, including visual processing, deficits have been linked to functional outcome in schizophrenia. A secondary goal of this project is to examine the relationship between visual pathway dysfunction and social/global outcome deficits in schizophrenia. Human visual processing is conducted through parallel magnocellular and parvocellular pathways, which extend mainly into dorsal stream (parietal lobe) and ventral stream (temporal lobe) regions, respectively. Dorsal stream dysfunction has been well documented in schizophrenia. Increasing evidence suggests dorsal stream deficits are due to lower level magnocellular dysfunction. Understanding integrity of visual pathways is crucial to understanding higher level visual dysfunction in schizophrenia. A unique feature of this application is the use of visual evoked potentials (VEP) to evaluate integrity of visual pathways. High density VEP recordings will provide information not only about magnocellular versus parvocellular dysfunction, but also about localization of deficits. MRI studies will evaluate white matter integrity in lower level as well as dorsal and ventral visual stream areas. These combined techniques will provide important information regarding localization of the deficit. VEP and psychophysical studies will be highly integrated with studies of social/global outcome. The specific aims are: 1) to further characterize magnocellular versus parvocellular visual pathway dysfunction in schizophrenia; 2) to explore relationships between magnocellular visual pathway dysfunction and social/global functioning deficits in patients with schizophrenia; and 3) to examine structural correlates of visual processing dysfunction in patients with schizophrenia.