Sex commonalities and differences in obesity-related alterations in intrinsic brain activity and connectivity

OBJECTIVE: To characterize obesity-related sex-differences in intrinsic activity/connectivity of the brain’s reward networks. METHODS: Eighty-six women (N=43) and men (N=43) completed a 10-minute resting functional MRI scan. Sex differences and commonalities in BMI-related frequency power distribution and reward seed-based connectivity were investigated using partial least squares analysis. RESULTS: WHOLE BRAIN ACTIVITY: In both men and women, increased BMI was associated with increased slow-5 activity in left globus pallidus and substantia nigra. In women only, increased BMI was associated with increased slow-4 activity in right globus pallidus and bilateral putamen. SEED-BASED CONNECTIVITY: In women, increased BMI was associated with reduced slow-5 connectivity between left globus pallidus/putamen and emotion and cortical regulation regions, but in men was increased with medial frontal cortex. In both men and women, increased BMI was associated with increased slow-4 connectivity between right globus pallidus/bilateral putamen and emotion regulation and sensorimotor-related regions. CONCLUSIONS: The stronger relationship between increased BMI and decreased connectivity of core reward network components with cortical and emotion regulation regions in women may be related to the greater prevalence of emotional eating. The present findings suggest the importance of personalized treatments for obesity that consider the sex of the affected individual.