Eating disorders (EDs) are associated with high levels of mortality and impaired quality of life. Their treatment is complex, invasive, and often failed. The poor understanding of their neurophysiological bases hinders the development of effective interventions. Dysfunctional inhibitory control has been implicated in EDs with anorexia nervosa at the over-controlling boundary and bulimia nervosa/binge eating disorders at the opposite impulsive extremity. Neuroimaging studies consistently reported alterations in cerebellar circuitry in EDs, and recent findings indicated cerebellum (Cb) role in inhibitory control of thoughts and actions. The involvement of Cb in visceral and autonomic homeostasis in feeding behavior and appetite regulation, was repeatedly highlighted. The cerebellar cortex projects to the dentate nucleus, which has bidirectional connections with the hypothalamus that finally regulates food intake. However, very little is currently known about the neurocognitive physiology of food-related inhibitory control. The current project's goal is to understand the functional role of the cerebellum in self-regulatory inhibitory control. We hypothesize that real-time effective cerebellar connectivity and inhibitory control are related to EDs symptoms. Namely, the current project aims to determine how a single session of non-invasive stimulation of the cerebellar cortex by employing different transcranial direct current stimulation (tDCS) protocols coupled with the presentation of visual food stimuli may modulate food-specific inhibitory control in healthy participants. Two new experimental tasks are designed to evaluate self-regulatory food-related inhibitory control: a motor food-specific Go/NoGo and a cognitive food specific task-switching paradigms. In a randomized cross-over design, task performance following cathodal/anodal/sham cerebellar tDCS will be correlated with body mass index and a psychological assessment of impulsivity traits.
EDs are disabling and costly biopsychosocial conditions for patients, caregivers, and Western society. EDs affect somehow a large part of the population (not just women) with an increasingly precocious peak age of onset in pre-adolescence. Unfortunately, once the disorder has appeared, it tends to become chronic. The related mortality risk is higher than for other serious diseases, such as asthma or diabetes but the efficacy of the available psychological, nutritional and pharmacological treatments is still weak. Accordingly, this situation calls for the identification of the neurobiological basis of this complex disorder and for the development of novel therapeutic approaches. Often psychiatry, neurophysiology, and neuropsychology move in a non-synergistic way and miss thus the opportunity to join forces to develop targeted and effective treatments of challenging clinical conditions.
The present project aims to meet these needs in different ways, first of all starting to study the functional physiology of food-related inhibitory control in healthy people. These results will be of immediate translational value for the development of new treatment perspective using cerebellar non-invasive neuro-modulation combined with visual stimulation in EDs. Moreover, the project would characterize cognitive markers of healthy inhibitory control related to food stimuli and establishing links between impulsive traits and weight control.