Abstract
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Objectives: Impairment of impulse control has been linked to a broad spectrum of problems including obesity. The mechanism underlying the modulation of self-control is poorly understood. We assess the brain circuits involved in cognitive inhibition (CI) of hunger during food presentation (FP). Methods: Thirteen healthy women (33.6 ±8.6 yrs of age) with body mass index (BMI) of 25.1±2.9 and 10 age and BMI matched men were evaluated with PET and FDG. Brain metabolism was evaluated in food-deprived subjects during 3 conditions: No stimulation (NS), FP with CI and FP without CI in 3 separate days. The absolute metabolic images were analyzed using SPM and ROI methods. Self-report of hunger was measured (scaled 1-10). Results: The subjects had lower scores in hunger during CI (5.1±2.8) than without CI (8.1±1.3, p<0.0001) and men reported lower hunger during CI than women (p<0.03). Whole brain metabolism was higher for FP than for NS (35.9±4.5µmol/100g/min, p<0.0006) but whole brain metabolism did not differ for FP with CI (40.1±6) vs FP without CI (43.3±9.2). However, there were significant sex differences in the regional activation for FP without CI vs FP with CI. FP with CI in men decreased metabolism when compared to FP without CI in right striatum (58.1±7.5 vs 51.9±4.8 µmol/100g/min; p<0.01), left amygdala (30.1±4.4 vs 25.1±2.2; p<0.005) and left hippocampus (34±4.2 vs 25.1±2.2; p<0.02), women did not show a difference in FP with CI and without CI. Suppression in orbitofrontal (OF) activity during FP with CI in men was associated with decreases in hunger (r = 0.73; p < 0.02) but not in women. Conclusions: Suppression of activation during FP with CI in men in striatum, hippocampus and amygdala, which are regions involved in the regulation of satiety and motivation to eat suggests this is the mechanism by which cognitive inhibition decreases the desire for food. The association between suppression of OF activation and hunger in men corroborates this region in processing motivation of food consumption. Lower cognitive control in women than in men to food stimulation may account for sex differences in compulsive eating behaviors.
Research Support (if any): DOE/OBER, NIAAA and NIH/GCRC
- Society of Nuclear Medicine, Inc.