The relationship between cortical thickness and language comprehension varies with sex in healthy young adults: a...

Functional neuroimaging studies evaluating sex differences in language processing have been previously reported. However, it remains largely unclear whether there are structural bases for language comprehension and whether these are partially affected by sexual dimorphism in cortical thickness. To this end, we performed correlation analysis between cortical thickness and language comprehension in a large (N = 1017, 549 females, 468 males) young and healthy subjects from Human Connectome Project, with a specific focus on the impact of sex. We identified significant relationship between cortical thickness of the posterior cingulate cortex (PCC) and vocabulary comprehension in females (r = 0.318, r = 10%), while the association was significantly reduced in males (P = 0.017, Cohen's q = 0.154). Furthermore, thickness difference in the PCC was observed to be smaller in females (P < 0.0001, t = -7.12, Cohen's d = 0.45); however, the difference disappeared when controlling for brain size (Cohen's d = 0.002). Our findings indicated that variability in cortical thickness may affect cognitive function much more in females than in males, and highlighted the importance of brain size in explaining sex-specific cortical thickness.