Homeostatic and Non-homeostatic Processing of Food Cues in Anorexia Nervosa

Anorexia nervosa (AN) is an eating disorder with high morbidity and lifetime mortality. This eating disorder is mainly characterized by restricted food intake despite a severely low body weight. Given the pronounced self-starvation in AN, the investigation of homeostatic food processing, and its interaction with the reward system is of great scientific interest. Previous research in AN patients has almost exclusively focused on cortical, non-homeostatic (e.g., reward related) food processing. Therefore, the primary aim of the present study is to investigate metabolic gut-brain signaling by focusing on the responsivity of the hypothalamus (i.e., the core region of homeostatic control) and the mesocorticolimbic reward system. A secondary aim is to study the interaction between the mesocorticolimbic reward system and the homeostatic (i.e., hypothalamus) system. Metabolic gut-brain signaling will be assessed by applying a single-blind, randomized, crossover design of intragastric infusion of glucose or water. This approach allows the study of gut-brain signaling to the hypothalamus and the reward system by controlling for sensory aspects of food intake (sight, smell, and taste) in AN patients and healthy controls. Furthermore, we will measure how cognitive strategies to control the desire for visual food cues (top-down control) affect the mesocorticolimbic and hypothalamic systems in AN patients differently than in healthy controls. The interaction between the hypothalamus and the mesocorticolimbic reward system will be investigated using an effective connectivity analysis. Functional magnetic resonance imaging with high spatial resolution and with an optimized protocol for the investigation of the hypothalamus and the mesocorticolimbic reward system will be used to study for the first time homeostatic and non-homeostatic food cue processing in AN patients.