Motor- and food-related metabolic cerebral changes in the activity-based rat model for anorexia nervosa: a voxel-based microPET study.

Anorexia nervosa (AN) is a disorder that is difficult to treat with psycho- or pharmacotherapy. In order to identify involved neurocircuitry, we investigated the cerebral metabolic alterations in the activity-based anorexia (ABA) rat model, where restriction of the food intake period induces hyperactivity and decreased body weight. Cerebral (18)F-fluorodeoxyglucose uptake was investigated in rats in the activity-based anorexia model (n=9) and compared to controls (n=10), using a CTI Focus microPET 220. Regional metabolic changes were investigated using statistical parametric mapping (SPM2) and correlated to weight and hyperactivity measures on a voxel-by-voxel basis. Higher regional metabolism was found in ABA rats in the mediodorsal thalamus, ventral pontine nuclei and cerebellum, while hypometabolism was seen in the left rhinal and bilateral insular cortex, and bilateral ventral striatum (p<0.001). A positive correlation was observed between body weight loss and brain metabolism in the cingulate cortex and surrounding motor and somatosensory cortex (p<0.001). Thus, in the ABA model metabolic changes are present in brain areas related to disease status and weight loss, which share several characteristics with the human disease.