Obesity linked to progressive brain structural changes

Individuals with obesity show changes in gray matter volume that stem from the reward/motivation processing regions and may expand to inhibitory control/learning memory regions, reveals a study.

The authors obtained T1-weighted magnetic resonance images from 258 participants with overweight or obesity and 74 participants with normal weight. They divided those with overweight or obesity into four groups based on BMI grades. Two-sample t tests were used to compare differences between the four subgroups and the participants with normal weight.

Finally, the authors explored the progressive impact of obesity on brain structure using causal structural covariance networks.

Reductions in gray matter volume among participants with increased BMI values appeared to originate in the left caudate nucleus, medial orbitofrontal cortex, and left insula and progressed to the right hippocampus and left lateral orbitofrontal cortex, then to the right parahippocampal gyrus, left precuneus, and left dorsolateral prefrontal cortex (p<0.05, false discovery rate corrected).

The primary hubs of the directional network were the left caudate nucleus and the medial orbitofrontal cortex, which demonstrated positive causality to the right hippocampus and left dorsolateral prefrontal cortex. In addition, the right hippocampus was found to be an important transition hub.

“These findings suggest that changes in gray matter volume in individuals with obesity may originate from reward/motivation processing regions, subsequently progressing to inhibitory control/learning memory regions, providing a new reference direction for clinical intervention and treatment of obesity,” the authors said.