Obesity, defined as BMI> 30kg / m2, is a major public health problem, with devastating medical and psychological consequences. 30% of obese suffer from BED type of eating disorders. The optimal treatment of obesity remains bariatric surgery, failed in 20% of cases. Many arguments are in favor of the involvement of the reward circuitry, with the central role of NAc in the pathophysiology of BED and obesity. The recent application and effectiveness of DBS (Deep Brain Stimulation) in refractory psychiatric disorders suggest that DBS may be of interest in treating obesity and BED with potential target for the NAc. This project propose to study fMRI activation of the reward system in response to food stimuli to better direct the DBS targets. This is a pilot study to define indication criteria based on fMRI to obese BED patients are potential candidates for treatment with DBS.

The aim of this functional neuroimaging study is to analyze brain responses to visual food cues in obese (body mass index > 97th percentile) adolescents with BED (according to the criteria Marcus and Kalarchian) compared with healthy control adolescents in two situations : hunger et satiety.

Fifteen obese adolescents (12/16 years) with BED and fifteen healthy control adolescents will be enrolled in the study protocol. Participants will be instructed not to eat food for at least 6 hours prior to the first imaging session. After the initial set of functional and anatomic scans, participants will be fed a standard calorie meal. Approximately 1 hour later, the experiment will be repeated while participants are in a satiated condition. The cortical fMRI activation will be measured during the following four experimental visual conditions : high calory food, low calory food, disgust and neutral presented in block design.

First-level and second-level differences in neural activation assessed during functional MRI in the different conditions will then be analyzed.

Inclusion Criteria:

• Non specific inclusion criteria

  • Age limits ≥ 12 et < 16 years
  • Collection of the informed consent. For the minor patients, signature of parents
  • Affiliation or recipient with the mode of social security.
  • No associated evolutionary pathologies

• Specific inclusion criteria for the patients

  • Existence of a current food disorder of the conducts of type binge eating disorder according to the criteria Marcus and Kalarchian
  • Diagnosis of obesity defined by a body mass index > 97th percentile
  • Severity criteria defined by: Evolution of the obesity and the BED for at least 5 years AND Not answer to a dietary, pharmacological, psychotherapeutic care during at least 6 months

• Specific inclusion criteria for the volunteers

  • Absence of a current food disorder of the conducts of type binge eating disorder according to the criteria Marcus and Kalarchian
  • Absence of antecedent of neurological disorder
  • an actual body mass index < 90th percentile

Exclusion Criteria:

• IRM contraindication
• Pacemaker
• Port(Bearing) of surgical clips in the cervico-cephalic region or implanted medical surgical material(equipment) susceptible to mobilize under the influence of magnetic gradients
• Intraocular foreign body
• Metalic foreign body
• claustrophobia
• The existence of possible psychiatric histories will be individually estimated
• Pregnancy and breastfeeding
• Loss of liberty by court or administrative order