Overcontrol in anorexia nervosa: Elevated prefrontal activity and amygdala connectivity in a working memory task with food distractors

Abstract

Individuals with anorexia nervosa (AN) are thought to engage in excessive amounts of self-control, which may contribute to disorder development and maintenance. This “overcontrol” may explain previous findings of increased activity and connectivity in frontal brain regions involved in top-down control functions in response to diverse stimuli including emotionally salient visual food stimuli. However, these observations were made largely in tasks demanding explicit stimulus processing. Given the omnipresence of food cues and their particular relevance for AN, it deems important to test if these alterations are also present when food stimuli are task-irrelevant. To this end, we acquired functional magnetic resonance imaging data during a working memory 2-back task with images of high-caloric food as distractors in 32 acutely ill young women with AN and 32 age-matched female healthy control participants. Neural activity and connectivity was analyzed in a priori specified regions of interest involved in top-down control (dorsolateral prefrontal cortex; dlPFC) and affective processing (amygdala). Despite no group differences in task performance, activity of the left dlPFC was higher in AN compared with healthy controls across both food and non-food conditions. AN also showed increased negative connectivity between the left dlPFC and bilateral amygdalae. Generally increased dlPFC activation and altered dlPFC-amygdala connectivity in the context of our task is suggestive of excessive top-down control in AN. This activation pattern may reflect a neural substrate of overcontrol which occurs independent of external stimuli. This mechanism may be a potential treatment target, as it mirrors the clinical presentation of the disorder.