Sex differences in patterns of hemispheric cerebral metabolism: a multiple regression/discriminant analysis of positron emission tomographic data

Sex differences in brain hemispheric structure and function have been reported, and sex-related differences in hemispheric interregional correlations were reported in a prior analysis of resting PET glucose metabolic (rCMRglc) data. To explore further the effect of sex on patterns of hemispheric brain functional interactions, we applied a multiple regression/discriminant analysis to resting rCMRglc PET data from young normal men and women to test two hypotheses: (1) women have stronger between-hemisphere functional interactions; (2) men have stronger within-hemisphere functional interactions. Two separate discriminant functions based on these hypotheses distinguished men and women: the first reflected rCMRglc interdependencies between hemispheres and correctly classified all women and 94% of the men; the second reflected rCMRglc interdependencies within the left hemisphere and correctly classified 82% of the women and 88% of the men. Because the discriminant functions successfully distinguished men and women, these results provide support for both hypotheses.