Cortical intercorrelations of frontal area volumes in schizophrenia

Abnormal regional volume intercorrelations between selected cortical areas in schizophrenia patients were previously reported in several MRI studies. A detailed analysis of frontal gray and white matter volume correlations with Brodmann's area volumes in the rest of the cortex was undertaken in normal subjects ( n = 42) and patients with schizophrenia ( n = 106), divided into good-outcome ( n = 52) and poor-outcome (Kraepelinian; n = 54) subtypes. Frontal gray matter volumes were correlated with temporal lobe volumes in schizophrenics but not in normal subjects. Some frontal–parietal and frontal–occipital correlations showed a similar pattern. In comparison to normal subjects, schizophrenia patients showed weaker or absent intercorrelations intrafrontally, specifically between left motor–premotor and eye-movement areas (4, 6, 8) and dorsolateral area 44, as well as between left areas 9 and 46 vs. area 24 (cingulate gyrus). Poor outcome among patients with schizophrenia was associated with weaker correlations between left frontal area 9 and both medial and lateral temporal cortices, as compared to normal subjects or good-outcome patients. There appears to be a structural component in the task or symptom-related dysfunctional interactions between the frontal and more posterior cortical regions with preferential pathological involvement of frontotemporal and more limited involvement of frontoparietal and fronto-occipital systems in schizophrenia. Impaired regional associations within the frontal lobe, between left motor–premotor and Broca's areas, may play a role in language processing deficits in schizophrenia, while frontocingulate disconnection may result in working memory disturbances. Poor outcome may be associated with more widespread disconnections between prefrontal vs. cingulate and temporal regions in the left hemisphere, consistent with a disruption along the course of the left cingulum or uncinate bundles.