Executive control circuitry differentiates degree of success in weight loss following gastric-bypass surgery.

Abstract

While overall success rates of bariatric surgery are high, approximately 20% of patients either regain or never lose the expected amount of weight. The purpose of this study was to determine whether, after gastric-bypass surgery, the degree of weight loss can be differentiated based on the neural response to food cues. In this functional MRI study, 31 post-surgical patients viewed food and neutral images in two counterbalanced runs during which they were either instructed to "crave" or to "resist" craving. The neural response to food cues was assessed within and between runs for all participants, and further analyzed between more successful (n = 24) and less successful (n = 7) groups. More successful was defined by meeting 50% excess weight loss. Overall, instructions to "crave" elicited significant activity in the dorsomedial prefrontal cortex (PFC) whereas "resist" elicited significant activity in the dorsolateral PFC (DLPFC). Between groups there was no brain difference when instructed to "crave." The more successful participants however had significantly more activity in the DLPFC when instructed to "resist." These findings suggest that the ability to mobilize neural circuits involved in executive control post-gastric-bypass surgery may be a unique component of successful outcome post-surgery.