ORIGINAL ARTICLE Early-Stage Visual Processing and Cortical Amplification Deficits in Schizophrenia

Background: Patients with schizophrenia show defi-cits in early-stage visual processing, potentially reflect-ing dysfunction of the magnocellular visual pathway. The magnocellular system operates normally in a nonlinear amplification mode mediated by glutamatergic (N-methyl-D-aspartate) receptors. Investigating magnocellular dys-function in schizophrenia therefore permits evaluation of underlying etiologic hypotheses. Objectives: To evaluate magnocellular dysfunction in schizophrenia, relative to known neurochemical and neu-roanatomical substrates, and to examine relationships be-tween electrophysiological and behavioral measures of visual pathway dysfunction and relationships with higher cognitive deficits. Design, Setting, and Participants: Between-grou