Gender and age differences in normal adult human brain: voxel-based morphometric study.

The aim of this study was to evaluate the gender and age differences in the normal adult human brain, using voxel-based morphometry. In this study, 227 right-handed normal adults (male:female = 111:116) were examined. Three-dimensional magnetic resonance brain images of each subject were segmented into gray and white matter using statistical parametric mappings. All individual data were transformed to standard brain space and then divided into older and younger age groups before examining the effects of age and gender. There was a significant negative correlation between gray matter concentration and age in each gender group. The differences were more prominent in the older age groups compared with the younger age groups. Gray matter concentrations in the bilateral inferior frontal lobes, anterior cingulate gyrus, medial thalamus, and hypothalamus were more retained in females as they aged, whereas those in the occipital regions were more retained in aging males. Our findings are consistent with biologically and hormonally established gender differences.