Variations in brain responses to sensory stimuli are typically considered to lack information content and treated as "noise". Alternatively, variable response patterns may reflect the adjustment of biological parameters to external factors. We used functional magnetic resonance imaging in healthy non-dieting individuals to test whether intra-individual variation in brain response to the receipt of milkshake is associated with a range of behavioral and metabolic parameters. We found that, following a meal, high variability in nucleus accumbens (NAcc) response to milkshake is associated with higher body mass index, greater dietary disinhibition, more variable ad libitum food consumption, faster increases in plasma insulin, faster decreases in plasma glucose, and greater weight loss over 1year. Our results thus uncover a series of physiological parameters encrypted as variable responses in NAcc to food stimuli. They also suggest that variations in striatal activity regulate the activation of behavioral and metabolic responses to food availability.
Keywords: BMI; Food reward; Glucose metabolism; Insulin sensitivity; Neural variability; fMRI.
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