Anorexia Nervosa and Obesity are Associated with Opposite Brain Reward Response

Abstract

Anorexia nervosa (AN) is a severe psychiatric disorder associated with food avoidance and malnutrition. In this study, we wanted to test whether we would find brain reward alterations in AN, compared with individuals with normal or increased body weight. We studied 21 underweight, restricting-type AN (age M 22.5, SD 5.8 years), 19 obese (age M 27.1, SD 6.7 years), and 23 healthy control women (age M 24.8, SD 5.6 years), using blood oxygen level-dependent functional magnetic resonance brain imaging together with a rewardconditioning task. This paradigm involves learning the association between conditioned visual stimuli and unconditioned taste stimuli, as well as the unexpected violation of those learned associations. The task has been associated with activation of brain dopamine reward circuits, and it allows the comparison of actual brain response with expected brain activation based on established neuronal models. A group-by-task condition analysis (family-wise-error-corrected Po0.05) indicated that the orbitofrontal cortex differentiated all three groups. The dopamine model reward-learning signal distinguished groups in the anteroventral striatum, insula, and prefrontal cortex (Po0.001, 25 voxel cluster threshold), with brain responses that were greater in the AN group, but lesser in the obese group, compared with controls. These results suggest that brain reward circuits are more responsive to food stimuli in AN, but less responsive in obese women. The mechanism for this association is uncertain, but these brain reward response patterns could be biomarkers for the respective weight state.

Reduced salience and default mode network activity in women with anorexia nervosa

“…We found opposite functional brain response in women with anorexia nervosa compared with obese individuals, 8 suggesting opposite brain pathology. As previous studies have found increased intrinsic DMN activity in obese individuals, we hypothesized that DMN activity in women with anorexia nervosa would be reduced and thus opposite to that seen in obesity.…”

“…1 While the neurobiologic al mechanisms underlying anorexia nervosa are not well understood, neuroimaging studies have found altered brain activation in brain regions contributing to reward and anxiety processing in individuals with anorexia nervosa. [2][3][4][5][6][7][8][9][10][11] Such alterations could be involved in the pathologic drive to eat in these individuals. 6,8 To gain a clearer understanding of neurobiological mechan isms involved in anorexia nervosa, it is important to under stand the functionality of the brain networks that underlie illness behaviour.…”

“…[2][3][4][5][6][7][8][9][10][11] Such alterations could be involved in the pathologic drive to eat in these individuals. 6,8 To gain a clearer understanding of neurobiological mechan isms involved in anorexia nervosa, it is important to under stand the functionality of the brain networks that underlie illness behaviour. The focus of this study was to investigate intrinsic network activity in women with anorexia nervosa, women recovered from anorexia nervosa and healthy control women to determine if there are differences in brain circuit functionality related to disease state or possible trait abnormalities.…”

Neural responsivity during soft drink intake, anticipation, and advertisement exposure in habitually consuming youth

“…13 were Coke consumers and 12 were nonsoda drinkers (Table 1), 2 qualified for neither consumer category and were only included in the subsample analysis. A Coke consumer was defined as consuming >5 Coca-Cola Classics ® (12floz/Coke) per week for more than the previous month.…”

“…In contrast, obese versus lean individuals show less striatal activity during palatable food intake (12)(13)(14), which may delay meal termination if individuals are seeking the previously experienced pleasure from food intake. In support, objectively measured food intake beyond needs correlated positively with activity in attention and gustatory regions when anticipating palatable food receipt (15), and striatal response during intake correlated negatively with frequency of consumption of foods similar to those in the scan (16,17).…”