Deciphering the Neural Mechanisms of Restrictive Eating in Anorexia Nervosa Using Repetitive Transcranial Magnetic Stimulation

Anorexia nervosa (AN) is a devastating illness with morbidity and mortality rates among the highest associated with any psychiatric disorder. Treatments for adults with AN have limited efficacy due to an inadequate understanding of the mechanisms underlying AN's core symptoms. The salient feature of AN is extreme restriction of food, particularly dietary fat intake, a behavior both highly resistant to change and central to relapse. Neuroimaging research of food restriction in AN has found that compared to healthy controls, patients with AN exhibit greater choice-related dorsal striatum activation and different connection strength within dorsal fronto-striatal circuits, suggesting that activity in this region and associated circuits may underlie maladaptive eating behavior. To confirm the significance of these brain regions in restrictive eating, this study will combine neuronavigation-guided high-frequency rTMS (HF-rTMS), individualized functional TMS targets, fMRI and a computerized food-choice task to test the effects of HF-rTMS on restrictive food choice and associated neural activity.

The study will utilize a double-blinded randomized parallel design: adult inpatients with AN will receive either HF-rTMS or sham to the DLPFC. We will compare group changes in brain and behavior to test whether activity in the dorsal striatum underlies restrictive eating behavior in AN and quantify the effects of HF-rTMS to the DLPFC on restrictive eating behavior. Our use of individualized TMS targets will enable us to identify whether resting-state functional connectivity predicts neural or behavioral response to HF-rTMS.