REward SYSTem in Autism Spectrum Disorder and Addictive Disorder

Who May Qualify: Arm A ˗ Concerning ASD patients: Adult carrying the diagnosis of ASD (DSM-5, ADOS, ADI-R criteria) Arm B ˗ Concerning FAD patients: Adult diagnosed with FA presenting with food addiction (DSM-5, YFAS 2.0, BES \>= 18 criteria). Arm C ˗ Concerning healthy volunteers : Adult with no neurological and psychiatric history , absence of progressive somatic pathologies or with vital risk. For all participants: - Age greater than or equal to 18 years old - Without intellectual delay (IQ \> 70). - Able to understand and apply the instruction when an active task is proposed, according to the estimate of the investigator. - Free, express, informed and written consent of the participant. - Participant affiliated to a social security scheme Who Should NOT Join This Trial: - Neuromotor disorders. - Visual disturbances not corrected or incompatible with MRI. - Known epilepsy. - Current substance use disorder with emotional distress/significant impact on functional outcome - Rare genetic syndrome. - Contraindications to MRI (other than body circumference) - For women of childbearing age: negative urine or blood pregnancy test - Person subject to a measure of judicial protection (safeguard of justice, curatorship, guardianship or family authorization) Always talk to your doctor about whether this trial is right for you.