Puberty's hormonal effects on the anatomy of the developing human brain are poorly understood. Sex-related differences in Grey Matter (GM) volume were investigated in 46 subjects aged 8 to 15 years in a voxel-based morphometry study. Males had larger GM volumes in the left amygdala, while females had larger GM volumes in the right striatum and bilateral hippocampal. A subsample of 30 subjects had sexually dimorphic areas linked to Tanner Stages (TS) of pubertal development and circulating levels of steroid hormones. Regardless of gender, amygdala and hippocampal volumes changed with TS and were linked to circulating testosterone (TEST) levels. Contrary to pubertal development and circulating steroid hormones, striatal GM volumes were unrelated. TEST levels and diencephalic brain structures were found to have positive associations with circulating oestrogen levels and parahippocampal GM volumes in whole-brain regression analyses. Furthermore, a negative relationship was discovered between circulating TEST and left parietal GM volumes. These findings imply that GM development in specific brain regions is linked to sexual maturation and that pubertal hormones may have organizational effects on the developing human brain.
