The results of gray matter volume (GMV) analyses of bilateral dIa. Part figure (a) shows the anatomical location of left dIa, the mean GMV of left dIa in males and females, the correlation between physical aggression and CMV of left dIa, and the mediation effect of GMV of left dIa on the association between sex and physical aggression from left to right. Part figure (b) shows the anatomical location of right dIa, the mean GMV of right dIa in males and females, the correlation between physical aggression and CMV of right dIa, and the mediation effect of GMV of right dIa on the association between sex and physical aggression from left to right. dIa, dorsal agranular insula; GMV, gray matter volume; L, left; R, right