SCHIZOPHRENIA - A DISEASE OF HETEROMODAL ASSOCIATION CORTEX

There is considerable evidence of disturbances of multiple brain areas in schizophrenia. The clinical features and findings from pathologic and neuro-imaging studies suggest primary involvement of a system of p arallel distributed networks within the neocortex-the phylogenetically recent heteromodal association cortex (HASC). There is evidence that HASC is a family of higher-order parallel distributed networks of circ uits, mediating complex representationally guided behaviors. We argue that HASC regions are especially involved in schizophrenia. Lesions of HASC in the disease are likely to be neurodevelopmental in origin (as evidenced by such examples as reversed planum temporale asymmetry) wh ich have been identified by magnetic resonance imaging as specific reg ions of disproportionately reduced local gray matter volumes, and by n europathologic examination as cellular migration disruptions. We belie ve the hypothesis of preferential heteromodal cortical abnormalities h as heuristic value, and briefly indicate how it opens new avenues for investigating this debilitating condition.