Sex-specific expression of Heschl's gyrus functional and structural abnormalities in paranoid schizophrenia.

OBJECTIVE: Evidence supports abnormal temporal lobe structure and function in schizophrenia. Some abnormalities, particularly involving the auditory cortex, appear to be sex specific. These findings were extended to anatomical and physiological descriptors.
METHOD: The authors quantified the volume, surface area, and three-dimensional location of Heschl's gyri on magnetic resonance imaging (MRI) images of 21 patients with paranoid schizophrenia and 24 healthy comparison subjects. Neuromagnetic localizations of the 100-msec latency auditory evoked field (M100) were compared with MRI-determined locations of Heschl's gyri, computed as the geometric center of mass of the volume.
RESULTS: Volumetric measures revealed small Heschl's gyri only in male patients. Asymmetry was found in the location of the Heschl's gyrus centroid (more anterior on the right) across all groups. Male comparison subjects had M100 locations posterior to the Heschl's gyrus centroid in the left hemisphere and close to the Heschl's gyrus centroid on the right, while male patients had M100 sources anterior to the Heschl's gyrus centroid on the left. All women had M100 locations posterior to the Heschl's gyrus centroid on the left and anterior to it on the right.
CONCLUSIONS: These results demonstrate that some temporal lobe abnormalities in schizophrenia are sex specific. They also suggest that the anomalous lateralization of the auditory evoked field cannot be explained by a shift in the underlying anatomy, since the anatomical substrate is lateralized in both comparison subjects and patients of both sexes. These findings may indicate a sex-specific functional reorganization in the auditory cortex in schizophrenia.