The Road Not Taken: Neural Correlates of Decision Making in Orbitofrontal Cortex.

Empirical research links human orbitofrontal cortex (OFC) to the evaluation of outcomes during decision making and the representation of alternative (better) outcomes after failures. When faced with a difficult decision, rats sometimes pause and turn back-and-forth toward goals, until finally orienting toward the chosen direction. Neural representations of reward in rodent OFC increased immediately following each reorientation, implying a transient representation of the expected outcome following self-initiated decisions. Upon reaching reward locations and finding no reward (having made an error), OFC representations of reward decreased locally indicating a disappointment signal that then switched to represent the unrewarded, non-local, would-have-been rewarded site. These results illustrate that following a decision to act, neural ensembles in OFC represent reward, and upon the realization of an error, represent the reward that could have been.