Obsessive Compulsive Disorder (OCD) is a complex neuropsychiatric disorder whose pathophysiology remains largely unknown. We aim at characterizing the interactions between dopaminergic neurons and orbito-frontal cortex during credit assignment from a computational standpoint. To do so, we perform combined intracranial EEG and MEG in OCD patients while they perform decision task. These neural data are analyzed in the light of algorithmic models of decision-making.