Effects of aging on the morphologies of Heschl's gyrus and the superior temporal gyrus in schizophrenia: a postmortem study.

The etiology of schizophrenia has been proposed to be neurodevelopmental based on neuroimaging and molecular biological studies. If there is neuronal vulnerability based on neurodevelopment failures in schizophrenic brains, then the impact of aging may have a greater effect on schizophrenic brains than on normal brains. To determine the impact of aging on schizophrenic brains, we investigated the age-related morphological changes of the cross-sectional area of the gray matter (GM) in the left Heschl's gyrus (HG) and the left superior gyrus (STG) in 22 schizophrenic and 24 age- and sex-matched normal control postmortem brains two-dimensionally. The subject groups were divided into younger groups (30-54years of age) and older groups (65-84years of age) on the basis of age at death. Both in schizophrenic and control subjects, the GM area in HG and the STG was significantly smaller in the older group than in the younger group, however, no significant differences were observed between the schizophrenic and control subjects. In the STG, the cross-sectional area of the white matter (WM) was also measured. In the older group, the ratio of the GM area to the WM area in the STG was significantly larger in schizophrenic subjects than controls, although there was no significant difference between the schizophrenic and control subjects in the younger group. These findings indicate that the impact of aging has a greater effect on the WM in the STG in schizophrenic subjects than in normal individuals, although the pathological basis is still unclear.