Background

Feeding is controlled by a cortical network with functional connectivity (FC) to the ventromedial hypothalamus (VMH) that regulates satiety and lateral hypothalamus (LH), motivation to initiate feeding.For the first time, we examined whether it differs in pediatric obesity and is modulated by vertical sleeve gastrectomy (VSG), a bariatric surgery resulting in weight loss and altered feeding-hormones.

Methods

Thirty-five adolescents (14-21 yrs) with severe obesity (BMI>95th percentile, OB:n=18) and with healthy weight (HW:n=17) underwent fMRI for 6 minutes in a resting-state.BMI was higher in OB (p<0.001); no differences in IQ, age, gender, ethnicity, race, family income, maternal education (ps>0.29).rsFC was examined in CONN, p<0.05 FDR-corrected. rsFC was compared between OB and HW at Time 1 and for changes at Time 2 (3 months later) in OB post-surgery (VSG:n=6) who lost 9 BMI points (p<0.001), those waiting for surgery (WL:n=6) who gained 1.3 BMI points, and HW (n=11) whose weight did not change.

Results

At Time 1, FC of VMH was higher in OB than HW to L rostral prefrontal and anterior cingulate cortex, L precuneus, mediofrontal cortex, and L hippocampus/parahippocampal gyrus; FC to R lateral orbitofrontal cortex was lower in OB; FC of LH did not differ.Relative to Time 1, Time 2 FC of VMH decreased to R posterior cingulate, precuneus, and lateral occipital cortex in VSG and increased to R lateral occipital cortex and angular gyrus in WL; HW did not change.

Conclusions

Alteration in OB of VMH circuitry implicated in satiety, but not initiation of feeding, is suggested by overconnectivity to reward valuation regions and underconnectivity to regions subserving goal directed choice. FC changes to right extrastriate visual and attentional regions paralleled weight change, decreasing in VSG and increasing in WL.These preliminary results suggest weight-loss induced modulation of satiety regulation and should be validated with hormonal and feeding-related behavior.