Learning substrates in the primate prefrontal cortex and striatum: sustained activity related to successful actions.

Learning from experience requires knowing whether a past action resulted in a desired outcome. The prefrontal cortex and basal ganglia are thought to play key roles in such learning of arbitrary stimulus-response associations. Previous studies have found neural activity in these areas, similar to dopaminergic neurons' signals, that transiently reflect whether a response is correct or incorrect. However, it is unclear how this transient activity, which fades in under a second, influences actions that occur much later. Here, we report that single neurons in both areas show sustained, persistent outcome-related responses. Moreover, single behavioral outcomes influence future neural activity and behavior: behavioral responses are more often correct and single neurons more accurately discriminate between the possible responses when the previous response was correct. These long-lasting signals about trial outcome provide a way to link one action to the next and may allow reward signals to be combined over time to implement successful learning.