Binge Eating (BE) and Obesity: Brain Activity and Psychological Measures before and after Roux-En-Y Gastric Bypass (RYGB).

Brain activity in response to food cues following Roux-En-Y Gastric Bypass (RYGB) in binge eating (BE) or non-binge eating (NB) individuals is understudied. Here, 15 RYGB (8 BE; 7 NB) and 13 no treatment (NT) (7 BE; 6 NB) women with obesity underwent fMRI imaging while viewing high and low energy density food (HEF and LEF, respectively) and non-food (NF) visual cues. A region of interest (ROI) analysis compared BE participants to NB participants in those undergoing RYGB surgery pre-surgery and 4 months post. Results were corrected for multiple comparisons using liberal (p < 0.006 uncorrected) and stringent (p < 0.05 FDR corrected) thresholds. Four months following RYGB (vs. no treatment (NT) control), both BE and NB participants showed greater reductions in blood oxygen level-dependent (BOLD) signals (a proxy of local brain activity) in the dorsomedial prefrontal cortex in response to HEF (vs. LEF) cues (p < 0.006). BE (vs. NB) participants showed greater increases in the precuneus (p < 0.006) and thalamic regions (p < 0.05 corrected) to food (vs. NF). For RYGB (vs. NT) participants, BE participants, but not NB participants, showed lower BOLD signal in the middle occipital gyrus (p < 0.006), whilst NB participants, but not BE participants, showed lower signal in inferior frontal gyrus (p < 0.006) in response to HEF (vs. LEF). Results suggest distinct neural mechanisms of RGYB in BE and may help lead to improved clinical treatments.

fMRI Food Cue Reactivity as a Predictor for BMI Change Following Roux-en-Y Gastric Bypass (RYGB) or Diet Intervention.

Prevalence of severe obesity continues to increase, with only bariatric surgery showing long-term efficacy for sustained weight loss. Individuals with severe obesity (vs normal weight) show greater fMRI responsivity to high energy dense (ED) vs low ED food cues and reduced responsivity post-surgery. We examined responsivity to high vs low ED cues pre-intervention in association with postsurgical (RYGB) or dietary weight-loss (dWL) change in BMI at 4 and 18 mo. Region of interest (ROI) analysis employed separate ANCOVA models; group as single factor with three levels and baseline activation and interaction with group covarying for age and gender as nuisance covariates. Significant results were identified at p < 0.1 false discovery rate (FDR) corrected, following multiple comparisons across ROIs. In the precentral gyrus (motor and motor readiness area), higher baseline activation was associated with greater %BMI reduction in RYGB at 4 and 18 mo and less %BMI reduction in dWL at 4 mo (p = 0.006 uncorrected, P < 0.1 FDR corrected). The findings show opposite directionality in predicting change in BMI for RYGB vs. dWL from responsivity to high vs low ED food cues in the precentral gyrus. Greater baseline motor planning to ingest high ED foods may be associated with reduced weight loss in dWL, and with greater weight loss in RYGB due to neuromodulatory effects of surgery.

Relationship between binge eating and associated eating behaviors with subcortical brain volumes and cortical thickness.

BACKGROUND: Binge eating disorder (BED) is the most prevalent eating disorder. We examined the presence of binge eating (BE) and three associated eating behaviors in relation to subcortical regional volumes and cortical thickness from brain scans. METHODS: We processed structural MRI brain scans for 466 individuals from the Nathan Kline Institute Rockland Sample using Freesurfer. We investigated subcortical volumes and cortical thicknesses among those with and without BE and in relation to the scores on dietary restraint, disinhibition, and hunger from the Three-Factor Eating Questionnaire (TFEQ). We conducted a whole-brain analysis and a region of analysis (ROI) using a priori regions associated with BE and with the three eating factors. We also compared scores on the three TFEQ factors for the BE and non-BE. RESULTS: The BE group had higher scores for dietary restraint (p = .013), disinhibition (p = 1.22E-07), and hunger (p = 5.88E-07). In the whole-brain analysis, no regions survived correction for multiple comparisons (FDR corrected p<0.01) for either BE group or interaction with TFEQ. However, disinhibition scores correlated positively with left nucleus accumbens (NAc) volume (p < 0.01 FDR corrected). In the ROI analysis, those with BE also had greater left NAc volume (p = 0.008, uncorrected) compared to non-BE. LIMITATIONS: Limitations include potential self-report bias on the EDE-Q and TFEQ. CONCLUSIONS: The findings show that BE and disinhibition scores were each associated with greater volumes in the left NAc, a reward area, consistent with a greater drive and pleasure for food.

Functional Magnetic Resonance Imaging (fMRI) of Neural Responses to Visual and Auditory Food Stimuli Pre and Post Roux-en-Y Gastric Bypass (RYGB) and Sleeve Gastrectomy (SG).

Of current obesity treatments, bariatric surgery induces the most weight loss. Given the marked increase in the number of bariatric surgeries performed, elucidating the mechanisms of action is a key research goal. We compared whole brain activation in response to high-energy dense (HED) vs. low-energy dense (LED) visual and auditory food cues before and approximately 4 months after Roux-en-Y Gastric Bypass (RYGB) (n = 16) and Sleeve Gastrectomy (SG) (n = 9). We included two control groups: a low-calorie diet weight loss group (WL) (n = 14) and a non-treatment group (NT) (n = 16). Relative to the control groups, the surgery groups showed increased dorsolateral prefrontal cortex (dlPFC) and decreased parahippocampal/fusiform gyrus (PHG/fusiform) activation in response to HED vs. LED, suggesting greater cognitive dietary inhibition and decreased rewarding effects and attention related to HED foods. dlPFC activation was significantly more increased in RYGB vs. SG. We also found that postprandial increases in GLP-1 concentrations (pre to postsurgery) correlated with postsurgical decreases in RYGB brain activity in the inferior temporal gyrus and the right middle occipital gyrus in addition to increases in the right medial prefrontal gyrus/paracingulate for HED > LED stimuli, suggesting involvement of these attention and inhibitory regions in satiety signaling postsurgery.