Emotional overeating is characterized by an excessive food intake in the context of intense emotional situations, such as acute stress one. Emotional overeating, as a behavioral trait, can increase the risk of to develop eating disorders or eating-related diseases, such as metabolic syndrome, obesity, type-2 diabetes. Recently, imaging modalities, such as magnetic resonance imaging (MRI) and electro-encephalography (EEG), have been adapted in order to perform neurofeedback consisting on presenting the brain activity instantaneously to the participant, that give him the possibility to modify this activity by his own mean. Neurofeedback has already shown some efficacy, either with explicit or implicit instruction. Compared with functional MRI (fMRI), functional near infra-red spectroscopy (fNIRS) is easy to handle, less expensive, and does not require a lying position. fNIRS is consequently more adapted for repeated acquisitions. Neurofeedback has already shown some promising results for neurological and psychiatric diseases. For mental states and emotion regulation, neurofeedback targeting the prefrontal cortex (PFC) has also shown promising outcomes. In this project, the investigators want to assess the effect of neurofeedback targeting the dorsolateral PFC (dlPFC) in a population of young adult women presenting emotional overeating. The investigators aim to improve the cognitive control and to reduce the episodes of emotional overeating in order to prevent the occurrence of subsequent pathologies. The intervention effect will be characterized with: (i) fMRI in order to evaluate the effect on cognitive control (with resting state fMRI or rsMRI) and on the reward system; (II) questionaries directly and one month after intervention in order to assess the behavioral effect. Besides an expected effect on emotional overeating, the investigators will evaluate whether an improvement of cognitive control can also promote positive effect on other behavioral traits that could lead to some pathologies such as food addiction. As a prerequisite to this study on emotional overeating (study B), the investigators will firstly validate on healthy subjects (study A) a reward anticipation fMRI task, which will be further used in study A in order to characterized the effect of neurofeedback on the reward system.