Besides food restriction, hyperactivity is considered a key behavioral trait of anorexia nervosa (AN), playing a major role in the pathogenesis and progression of the disorder. However, the underlying neurophysiology remains poorly understood. We used functional magnetic resonance imaging during two affective go/no-go tasks to probe inhibitory control in response to stimuli depicting physical activity vs inactivity and food vs non-food in AN patients compared with 26 healthy athlete and non-athlete controls. We hypothesized that neural correlates of behavioral inhibition are biased by the emotional information of the stimuli in AN patients, leading to a differential neural inhibitory pattern during the two tasks. Indeed, we found reduced response inhibition for food and non-food images in the putamen, while stimuli depicting physical activity resulted in an exaggerated response of the prefrontal cortex (PFC) and cerebellum in AN patients. However, both AN patients and athletes revealed an increased response in the somatosensory cortex to physical activity stimuli. These results suggest that physical activity stimuli might place an increased demand on the inhibitory control system in AN patients. The resulting hyperactivity of the PFC and cerebellum may lead to altered executive function and motor control, sustaining increased physical activity in AN patients.
Keywords: anorexia nervosa; eating disorder; fMRI; reward; hyperactivity; inhibitory control.
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