Ability to self-regulate a healthy body weight may depend on individual brain structure, say scientists in a recent study examining connections between executive control and reward regions in the brain.
Obesity and dieting are increasingly common in contemporary society, and many dieters struggle to lose excess weight. A research paper in Cognitive Neuroscience reports that dieting success may be easier for some people because they have greater structural integrity in the white-matter pathway connecting the executive control and reward systems in their brains.
Chronic dieters are known to show excessive reactions to food cues in executive control and reward areas of the brain, in addition to having depleted cognitive control and a greater tendency to overreward themselves with high-calorie foods in real-life situations.
Researchers took a group of 36 chronic dieters with mean body fat of 29.6% and asked them to make simple judgments on images, in order to divert their attention from the task’s real aim. The activity carried out was a food cue reactivity task designed to localize executive control and reward areas in the brain, using functional magnetic resonance imaging (fMRI). After localizing these areas, the researchers used diffusion tensor imaging (DTI) to identify the white-matter tract connecting them, in order to quantify its structural integrity.
The fMRI results demonstrated that dieters showed greater reactivity to food images than to control images. The DTI results further showed that those with lower body-fat percentages showed greater white-matter integrity in the tract between the executive control and reward areas of the brain. The findings support their hypothesis that structural integrity connecting the two centers relates to individual differences in body fat and is an indication of dieting success.
“Individuals with reduced integrity may have difficulty in overriding rewarding temptations, leading to a greater chance of becoming obese than those with higher structural integrity,” concluded the authors.