Disappointment entails the recognition that one did not get the value expected. In contrast, regret entails recognition that an alternative (counterfactual) action would have produced a more valued outcome. In humans, the orbitofrontal cortex is active during expressions of regret, and humans with damage to the orbitofrontal cortex do not express regret. In rats and nonhuman primates, both the orbitofrontal cortex and the ventral striatum have been implicated in reward computations. We recorded neural ensembles from orbitofrontal cortex and ventral striatum in rats encountering wait or skip choices for delayed delivery of different flavors using an economic framework. Economically, encountering a high-cost choice after skipping a low-cost choice should induce regret. In these situations, rats looked backwards toward the lost option, cells within orbitofrontal cortex and ventral striatum represented the missed action, rats were more likely to wait for the long delay, and rats rushed through eating the food after that delay.
Bibliographical noteFunding Information:
We thank C. Boldt and K. Seeland for technical support and other members of the Redish laboratory for discussion. This work was supported by US National Institutes of Health grants T32 NS048944 (A.P.S.), T32 DA007234 (A.P.S.) and R01-DA030672 (A.D.R.).