SEX-SPECIFIC EXPRESSION OF HESCHLS GYRUS FUNCTIONAL AND STRUCTURAL ABNORMALITIES IN PARANOID SCHIZOPHRENIA

Objective: Evidence supports abnormal temporal lobe structure and func tion in schizophrenia. Some abnormalities, particularly involving the auditory cortex, appear to be sex specific. These findings were extend ed to anatomical and physiological descriptors. Method: The authors qu antified the volume, surface area, and three-dimensional location of H eschl's gyri on magnetic resonance imaging (MRI) images of 21 patients with paranoid schizophrenia and 24 healthy comparison subjects. Neuro magnetic localizations of the 100-msec latency auditory evoked field ( M100) were compared with MRI-determined locations of Heschl's gyri, co mputed as the geometric center of mass of the volume. Results: Volumet ric measures revealed small Heschl's gyri only in male patients. Asymm etry was found in the location of the Heschl's gyrus centroid (more an terior on the right) across all groups. Male comparison subjects had M 100 locations posterior to the Heschl's gyrus centroid in the left hem isphere and close to the Heschl's gyrus centroid on the right, while m ale patients had M100 sources anterior to the Heschl's gyrus centroid on the left. All women had M100 locations posterior to the Heschl's gy rus centroid on the left and anterior to it on the right. Conclusions: These results demonstrate that some temporal lobe abnormalities in sc hizophrenia are sex specific. They also suggest that the anomalous lat eralization of the auditory evoked field cannot be explained by a shif t in the underlying anatomy, since the anatomical substrate is lateral ized in both comparison subjects and patients of both sexes. These fin dings may indicate a sex-specific functional reorganization in the aud itory cortex in schizophrenia.