NEURAL CORRELATES OF SUBJECTIVE FOOD VALUATION IN THE CONTEXT OF BARIATRIC SURGERY
Objective: To examine changes in the neural valuation of high- versus low-calorie stimuli following bariatric surgery and determine whether these changes relate to weight loss at 24 months. Methods: Adults undergoing bariatric surgery completed fMRI scans before surgery and at 4, 12 and 24 months post-surgery while performing the Becker-DeGroot-Marschak auction task to assess willingness-to-pay…
A study was conducted to investigate the alterations in neural valuation of high-calorie and low-calorie food stimuli after bariatric surgery and to determine if these changes correlate with weight loss at 24 months. Researchers recruited adults who were scheduled to undergo bariatric surgery and had them undergo functional magnetic resonance imaging (fMRI) scans both before the surgery and at various time points post-surgery, specifically at 4, 12, and 24 months.
The participants engaged in the Becker-DeGroot-Marschak auction task while in the scanner, which allowed researchers to gauge their willingness-to-pay (WTP) for various food stimuli. The team utilized linear mixed-effect models to analyze the longitudinal changes in WTP-related blood oxygen level-dependent (BOLD) responses, as well as how these responses interacted with total weight loss at 24 months post-surgery.
The findings revealed that WTP for high-calorie foods significantly decreased following the surgery, while the valuation of low-calorie foods remained consistent. At the 4-month mark, researchers observed an enhancement in WTP-BOLD associations for both high- and low-calorie stimuli within the frontoparietal control network and the right lateral orbitofrontal cortex compared to pre-surgery levels. However, these initial postoperative changes did not correlate with the 24-month weight loss outcomes.
Instead, greater weight loss at 24 months correlated with both pre-surgical and long-term changes (measured at 24 months versus pre-surgery) in WTP-BOLD associations within the precuneus, inferior parietal cortex, and visual cortex. In conclusion, bariatric surgery appears to induce early reductions in the valuation of high-calorie foods, potentially due to enhanced cognitive control and heightened aversive processing.
Nonetheless, the findings suggest that long-term weight-loss success is more strongly associated with trait-like neural differences in self-referential and attentional processing.
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