Establishing a link between sex-related differences in the structural connectome and behaviour

Abstract

One contribution of 16 to a theme issue 'Multifaceted origins of sex differences in the brain'. Recent years have witnessed an increased attention to studies of sex differences, partly because such differences offer important considerations for personalized medicine. While the presence of sex differences in human behaviour is well documented, our knowledge of their anatomical foundations in the brain is still relatively limited. As a natural gateway to fathom the human mind and behaviour, studies concentrating on the human brain network constitute an important segment of the research effort to investigate sex differences. Using a large sample of healthy young individuals, each assessed with diffusion MRI and a computerized neurocognitive battery, we conducted a comprehensive set of experiments examining sex-related differences in the meso-scale structures of the human connectome and elucidated how these differences may relate to sex differences at the level of behaviour. Our results suggest that behavioural sex differences, which indicate complementarity of males and females, are accompanied by related differences in brain structure across development. When using subnetworks that are defined over functional and behavioural domains, we observed increased structural connectivity related to the motor, sensory and executive function subnetworks in males. In females, subnetworks associated with social motivation, attention and memory tasks had higher connectivity. Males showed higher modularity compared to females, with females having higher inter-modular connectivity. Applying multivariate analysis, we showed an increasing separation between males and females in the course of development, not only in behavioural patterns but also in brain structure. We also showed that these behavioural and structural patterns correlate with each other, establishing a reliable link between brain and behaviour. BackgroundWhile the presence of sex differences in human behaviour and cognition is well documented [1,2], our knowledge of anatomical foundations for such sex differences, specifically in the brain, is still relatively limited. The enigmatic interplay between brain and behaviour, and its modulation by sex, has intrigued scientists, philosophers and the general public for decades. Behavioural differences include, but are not limited to, enhanced motor [3,4] and spatial skills [5,6] in males and improved memory [7,8] and social cognition [9,10] skills in females [11]. These differences may be attributed to the complementary roles that the sexes play in procreation and social structure; however, increasing evidence suggests the presence of corresponding sex differences in brain structure and function [12][13][14][15][16][17], as well as the presence of a strong connection between behaviour and brain structure [12,18]. Thus, relying merely on social and cultural effects to explain sex-induced variance in behaviour seems insufficient. Notably, although sex differences in the brain are present even in childhood [16,17], the

Sex differences in brain and behavior in adolescence: Findings from the Philadelphia Neurodevelopmental Cohort

“…The PNC dataset (Satterthwaite et al, 2014b), which includes structural, functional and behavioral parameters, provides a unique opportunity to identify age-related differences in the subnetworks of the structural connectome and elucidate how these differences relate to sex differences in behavior. We evaluated subnetworks in order to establish a reliable link between brain structure and behavior (Tunc et al, 2016). Our results suggest that sex differences in functional and behavioral dimensions are associated with related differences in the network properties of the structural connectome.…”

Complementarity of sex differences in brain and behavior: From laterality to multimodal neuroimaging

“…In a subsequent analysis, Tunc and colleagues (2016) further examined brain networks in the PNC in relation to sex differences. When using subnetworks that are defined over functional and behavioral domains, increased structural connectivity was observed in males related to the motor, sensory and executive function subnetworks.…”

Multimodal neuroimaging of male and female brain structure in health and disease across the life span

“…In (Duarte-Carvajalino et al, 2012), we found these topological measures are good predictors of the sex of the individual. In recent work, researchers used the same dataset as (Ingalhalikar et al, 2014) to identify possible functional and behavior assessments corresponding to the sex differences in connectivity networks (Tunc et al, 2016); they report higher connectivity in males in motor, sensory and executive function subnetworks and higher connectivity in females in reward and memory subnetworks.…”