In this article summary it is determined that in animal studies there is an alteration in brain activity in regions that underlie reward and taste perception. Obesity is a behavioral and metabolic disorder linked to diverse negative health outcomes. More than 64% of Americans are either overweight or obese. The dopamine pathway (DA) plays an important role in reward and conditioning and has been implicated in obesity and eating disorders.

Animal research suggests obesity is associated with changes in how the brain reward regions respond to food and food cues. Roux-en-Y gastric bypass (RYGB) is a very effective surgical procedure for significant and sustained weight loss, yet little is known regarding how this procedure affects the brain.

Key points: Obesity is a behavioral and metabolic disorder linked to diverse negative health outcomes. More than 64% of Americans are either overweight or obese. The dopamine pathway (DA) plays an important role in reward and conditioning and has been implicated in obesity and eating disorders. Animal research suggests obesity is associated with changes in how the brain reward regions respond to food and food cues. Roux-en-Y gastric bypass (RYGB) is a very effective surgical procedure for significant and sustained weight loss, yet little is known regarding how this procedure affects the brain. This study examined the effects of RYGB on the relationship between brain activity and food-reward anticipation in rats who underwent the procedure following a chronic high fat diet. Fifty-eight rats underwent RYGB surgery while 26 others underwent a sham procedure. Three weeks later the rats were conditioned to produce an association between a neutral food (chow) or a highly palatable food (bacon) with a particular chamber. Animals were scanned with positron emission tomography to measure brain metabolism. Results included:

  • Only rats in the RYGB group showed increased preference for the bacon-paired chamber while the rats receiving the sham surgery actually consumed more bacon
  • RYGB selectively activated brain regions related to reward, expectation, motivation, and addiction when the rats anticipated a highly palatable food

Why is this Relevant?

  • The dissociation between preference for the chamber and consumption of the bacon indicates these two behaviors do not share the same neurobiological process
  • The findings provide a possible mechanism to explain why some RYGB patients display increased susceptibility to non-food rewards after surgery, such as increased use of alcohol

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