Localized volume reduction in prefrontal, temporolimbic, and paralimbic regions in schizophrenia: an MRI parcellation study.

Functional and structural abnormalities of the anterior cingulate gyrus (ACG) in patients with schizophrenia have been repeatedly reported. However, one remaining issue is whether gray matter volume reduction in ACG exists to an extent comparable with, or even in excess of, that in other prefrontal and temporolimbic regions. High-spatial-resolution magnetic resonance imaging was performed on patients with schizophrenia (n=27) and on age-, gender-, and parental socioeconomic-status-matched healthy control subjects (n=27). After the gray and white matter were semiautomatically segmented, whole prefrontal and temporal lobes were manually parceled into 15 subregions-by-two hemispheres (30 regions of interest) constituting seven prefrontal gray matter regions, six temporal gray matter regions, the prefrontal white matter, and the temporal white matter. Compared with healthy subjects, schizophrenic patients showed significant gray matter volume reduction in the bilateral ACG, this being the largest effect size (left, 0.84; right, 0.56) among all the regions examined. There were also significant gray matter volume reductions in the bilateral posterior STG, bilateral inferior frontal gyrus, left posterior amygdala-hippocampal complex (mostly hippocampus), and the left insula. These results suggest that gray matter volume reductions in the ACG are prominent among prefrontal and temporolimbic regions in patients with schizophrenia. These findings indicate the importance of ACG abnormalities in the pathophysiology of schizophrenia.