Regional frontal abnormalities in schizophrenia: A quantitative gray matter volume and cortical surface size study

Background: Previous structural studies of the frontal lobe in schizophrenia have had somewhat inconsistent results, but most of them have measured the frontal lobe as a single brain structure. To investigate more specific abnormalities in frontal subregions, we measured gray matter volume and cortical surface size in 10 subregions in drug-naive patients during the early stages of the illness. Methods: Magnetic resonance imaging was used to measure frontal subregions in 34 healthy male volunteers, and 26 male, drug- naive schizophrenia patients at early stages of the illness. Frontal subregions were manually traced using our locally developed parcellation method. Results: Patients with schizophrenia had a significant deficit in cortical surface size in the right straight gyrus and left orbitofrontal cortex. No differences were found in gray matter volumes. Conclusions: Frontal structural abnormalities found in drug-naive schizophrenic patients appear to be subtle and circumscribed to ventral portions. Anomalies in the cortical surface size suggest neurodevelopmental abnormalities might occur during the early stages of the gyrogenesis. Further investigations are needed to explore the implications of paralimbic ventral frontal regions (i.e., straight gyrus and orbitofrontal cortex) in the pathophysiology of schizophrenia.