Abnormal of inter-hemispheric functional connectivity in elderly subjects with overweight/obesity.

BACKGROUND: There is a growing literature documenting a variety of brain abnormalities associated with obesity. However, little is known about the effects of obesity on inter-hemispheric connectivity in aging people.

METHODS: Participants included 61 cognitively intact elderly (including people with obesity, overweight, and lean controls) who underwent structural MRI, resting-state functional magnetic resonance imaging (rsfMRI) and standard neuropsychological batteries. Techniques including FreeSurfer and Voxel-mirrored Homotopic Connectivity (VMHC) were employed to evaluate inter-hemispheric structural and functional connectivity respectively.

RESULTS: There were no differences of cognitive abilities and vascular risks among groups. When compared to lean controls, obese group had greater VMHC in fusiform gyrus (FG); while overweight group had greater VMHC in FG, calcarine gyrus, inferior temporal gyrus (ITG), and postcentral gyrus (PCG). Moreover, the obesity group had lower VMHC in calcarine gyrus and PCG than overweight group (p<0.05, corrected).

CONCLUSIONS: The present study suggested, increased inter-hemispheric information transmission in networks supporting visual and sensorimotor function may lead to gain in weight, by possibly mediating diet behaviours of individuals.