Sex differences in adolescent white matter architecture

Abstract

Background Sex-specific trajectories in white matter development during adolescence may help explain cognitive and behavioral divergences between males and females. Knowledge of sex differences in typically developing adolescents can provide a basis for interpreting sexual dimorphisms in abilities and actions. Method We examined 58 healthy adolescents (12–14 years of age) with diffusion tensor imaging (DTI). Diffusion parameters fractional anisotropy (FA), and mean (MD), radial (RD), and axial diffusivities (AD) were subjected to whole-brain voxel-wise group comparisons using tract-based spatial statistics. Sex differences in white matter microstructure were examined in relation to pubertal development. Results Early adolescent females ( n = 29) evidenced higher FA in the right superior corona radiata, higher FA and AD in bilateral corticospinal tracts (≥ 164 μl, p < .01), and lower MD in the right inferior longitudinal fasciculus (ILF) and left forceps major (≥ 164 μl, p < .01) than age-matched males ( n = 29). Males did not show any areas of higher FA or lower MD than females, but had higher AD in the right superior longitudinal fasciculus, ILF, and forceps minor (≥ 164 μl, p < .01). Pubertal stage did not account for sex disparities. Conclusion In early adolescence, females' motor tracts may reflect widespread changes, while males may undergo relatively more microstructural change in projection and association fibers.