To review these studies, a delineation between omission and punishment as negative feedback in the task is necessary since the former leads to negative ‘reward PE’ (RPE) while the latter leads to positive ‘aversive PE’ (APE). It is observed that omission of areward suppresses dopamine neurons but delivery of a punishment activates dopamine neurons (Schultz, 2006, 2010; Niv, 2009). The phasic dopamine response to reward and omission of reward fitswell with prediction by the reinforcement learning theory