Effect of food-cues on aMCC glutamate modulation during inhibitory control post weight loss intervention: a 1H fMRS study

Objective: Poor inhibitory control may decrease weight loss maintenance. The neurobiological mechanisms are poorly understood. We investigated whether glutamate modulation in the anterior mid-cingulate cortex (aMCC) during response inhibition is impacted by food-cues and associated with self-reported behaviors and weight loss maintenance. Methods: 27 adults with overweight/obesity were recruited from a clinical weight management program. 1H fMRS (midline aMCC) was acquired during a visual-guided response inhibition task engaging two responding modes [non-selective (100% responses) or selective (withholding a response on 20% of trials)] applied with neutral (squares) or food/non-food cues. The impact of stimulus type on the aMCC glutamate modulation for each responding mode was assessed using a repeated measures GEE approach. Correlations were conducted between glutamate modulation, Three-Factor Eating Questionnaire scores, and long-term weight change. Results: The stimulus effect was significant during selective responding, driven by lower aMCC glutamate modulation during food/non-food cues. This glutamate modulation (selective; food/non-food) association with weight loss maintenance was a close trend (R2=0.15, p=0.054). The association with the TFEQ Cognitive Restraint was significant (R2=0.20, p=0.047). Conclusions: These results demonstrate an impact of food/non-food cues during response inhibition on the neurobiology and associations with long-term weight loss maintenance and scores related to eating behaviors.