Prefrontal mechanisms of behavioral flexibility, emotion regulation and value updating

Two ideas have dominated the neuropsychology of the orbitofrontal cortex (OFC). One holds that OFC regulates emotion and enhances behavioral flexibility through inhibitory control. The other ascribes to OFC a role in updating valuations based on current motivational states. Neuroimaging, neurophysiological and clinical observations are consistent with either or both hypotheses. Although these hypotheses are compatible in principle, the present results support the latter view of OFC function and argue against the former. We show that excitotoxic, fibersparing lesions confined to OFC in monkeys do not alter either behavioral flexibility, as measured by object reversal learning, or emotion regulation, as assessed by snake fear. A follow-up experiment indicates that previous reports of a loss of inhibitory control resulted from damage to nearby fiber tracts and not from OFC dysfunction. Thus, OFC plays a more specialized role in reward-guided behavior and emotion than currently thought, a function that includes value updating.