Sex differences in the structural connectome of the human brain

Abstract

Sex differences in human behavior show adaptive complementarity: Males have better motor and spatial abilities, whereas femaleshave superior memory and social cognition skills. Studies alsoshow sex differences in human brains but do not explain thiscomplementarity. In this work, we modeled the structural con-nectome using diffusion tensor imaging in a sample of 949 youths(aged 8-22 y, 428 males and 521 females) and discovered uniquesex differences in brain connectivity during the course of development. Connection-wise statistical analysis, as well as analysis ofregional and global network measures, presented a comprehensivedescription of network characteristics. In all supratentorial regions,males had greater within-hemispheric connectivity, as well as enhanced modularity and transitivity, whereas between-hemisphericconnectivity and cross-module participation predominated in females.However, this effect was reversed in the cerebellar connections.Analysis of these changes developmentally demonstrated differences in trajectory between males and females mainly in adolescence and in adulthood. Overall, the results suggest that male brainsare structured to facilitate connectivity between perception and coordinated action, whereas female brains are designed to facilitatecommunication between analytical and intuitive processing modes.