Gender differences of the brain structures in young high-altitude Tibetans

Gender differences in adaptation to high-altitude environments are evident, but the specific patterns in Tibetan brains remain unclear. We analyzed T1-weighted magnetic resonance imaging scans and neuropsychological test results from 61 male and 68 female Tibetans, with lowland Han participants as controls. Tibetan females had poorer performance than males in digit serial accumulation and forward digit span. Both Tibetan and Han males had significantly larger global gray matter volume and white matter volume than females, only Tibetan female brains contained a larger proportion of gray matter than male brains. Tibetan females (vs. males) had smaller regional gray matter volume in the left rostral middle frontal gyrus and pars opercularis and right caudal middle frontal gyrus, and gray matter volume in the left pars opercularis in all Tibetans had a significant positive correlation with forward digit span. Conversely, Tibetan females had greater cortical thickness in these regions, which negatively correlated with altitude. Han populations exhibited different gender-based patterns in gray matter volume and cortical thickness compared to Tibetans. These findings suggest that Tibetan female brains are more susceptible to high-altitude, and the observed gender differences in brain volume may relate to distinct neuropsychological performances.