The functional lateralization of white matter with sex differences

Numerous studies indicate that the brain demonstrates functional lateralization with distinct patterns between males and females, but they primarily have focused on gray matter, with only a handful considering white matter (WM) and sex differences. Utilizing rs-fMRI from the Southwest University Longitudinal Imaging Multimodal (SLIM) dataset, we quantified lateralization of WM as the difference in each region's synchronization with the left versus right hemisphere, and examined its temporal fluctuations and sex differences. Then, the Louvain community detection algorithm clustered lateralization patterns, and sex differences within each cluster were analyzed. We established the functional connectivity network, assessed its properties, and utilized correlation analysis to examine the relationship between lateralization and network. Our analyses revealed that WM demonstrated a left-lateralized trend in the left hemisphere and a right-lateralized trend in the right hemisphere. Moreover, functional lateralization was more pronounced in males than females. We also categorized the regions into three spatial clusters, revealing sex differences in the lateralization patterns within each cluster. Additionally, lateralization patterns are intricately associated with the functional connectivity network. These findings provide insights into functional lateralization and sex differences, and may inform future investigations of the neural mechanisms associated with functional specialization, cognition, behavior, and neurological disorders.