Widespread reward-system activation in obese women in response to pictures of high-calorie foods

LE Stoeckel, RE Weller, EW Cook III, DB Twieg… - Neuroimage, 2008 - Elsevier
LE Stoeckel, RE Weller, EW Cook III, DB Twieg, RC Knowlton, JE Cox
Neuroimage, 2008Elsevier
Behavioral studies have suggested that exaggerated reactivity to food cues, especially those
associated with high-calorie foods, may be a factor underlying obesity. This increased
motivational potency of foods in obese individuals appears to be mediated in part by a
hyperactive reward system. We used a Philips 3T magnet and fMRI to investigate activation
of reward-system and associated brain structures in response to pictures of high-calorie and
low-calorie foods in 12 obese compared to 12 normal-weight women. A regions of interest …
Behavioral studies have suggested that exaggerated reactivity to food cues, especially those associated with high-calorie foods, may be a factor underlying obesity. This increased motivational potency of foods in obese individuals appears to be mediated in part by a hyperactive reward system. We used a Philips 3T magnet and fMRI to investigate activation of reward-system and associated brain structures in response to pictures of high-calorie and low-calorie foods in 12 obese compared to 12 normal-weight women. A regions of interest (ROI) analysis revealed that pictures of high-calorie foods produced significantly greater activation in the obese group compared to controls in medial and lateral orbitofrontal cortex, amygdala, nucleus accumbens/ventral striatum, medial prefrontal cortex, insula, anterior cingulate cortex, ventral pallidum, caudate, putamen, and hippocampus. For the contrast of high-calorie vs. low-calorie foods, the obese group also exhibited a larger difference than the controls did in all of the same regions of interest except for the putamen. Within-group contrasts revealed that pictures of high-calorie foods uniformly stimulated more activation than low-calorie foods did in the obese group. By contrast, in the control group, greater activation by high-calorie foods was seen only in dorsal caudate, whereas low-calorie foods were more effective than high-calorie foods in the lateral orbitofrontal cortex, medial prefrontal cortex, and anterior cingulate cortex. In summary, compared to normal-weight controls, obese women exhibited greater activation in response to pictures of high-calorie foods in a large number of regions hypothesized to mediate motivational effects of food cues.
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