and the composite score as dependent variables, and the FA of callosal fibers in each segment as independent variables to investigate the relationship between the FA and cognitive function in all subjects. The statistical significance level was set at p < 0.0071 (adjusted for the Bonferroni correction; 0.05/7 cognitive scores) for cognitive tests. If we find significant relationship between FA of callosal fibers and z‐scores of cognitive subtests in all subjects, subsequent stepwise multiple regression analysis in same relation was performed in the SZ group. The statistical significance level was set at p < 0.05/number of tests (adjusted for the Bonferroni correction). Stepwise multiple regression analysis was also performed to investigate the relationship between the FA of callosal fibers in each segment and PANSS scores in the SZ group. The statistical significance level was set at p < 0.0125 (adjusted for the Bonferroni correction; 0.05/4 PANSS subtests). Independent‐samples t test was used to examine differences between the SZ and HC groups in the FA of callosal fiber in the segment which identified the significant relation in regression analysis in the SZ group. The statistical significance level was set at p < 0.05/number of tests (adjusted for the Bonferroni correction). In
