Neural substrates of anorexia nervosa: A behavioral challenge study with positron emission tomography

Objective: To delineate functional brain abnormalities associated with anor exia nervosa (AN). Study design: Positron emission tomographic measurements of regional cerebr al blood flow (rCBF) were performed on 8 female patients with AN and 8 heal thy female control subjects during exposure to 3 types of stimuli: high-cal orie foods, low-calorie foods, and non-food items. Heart rate and internal state analog scale scores were also obtained. Stereotactic transformation a nd statistical parametric mapping techniques were used to analyze imaging d ata. Results: During the high-calorie condition, control subjects reported a sig nificant desire to eat, whereas subjects with AN reported elevated anxiety and exhibited increases in heart rate. Patients with AN had elevated bilate ral medial temporal lobe rCBF compared with control subjects. Planned compa risons for group-by-condition interactions demonstrated greater activation within left occipital cortex and right temporo-occipital cortex for the hig h-calorie versus low-calorie contrast in patients with AN compared with con trol subjects. Conclusions: Our finding of elevated rCBF within bilateral medial temporal lobes is similar to published results in patients with psychotic disorders and may be related to the body image distortion common to AN. The high-calo rie food phobia exhibited by patients with AN appears to be associated with exaggerated responses in visual association cortex, as has been previously observed in studies of specific phobias.