Passively learned spatial navigation cues evoke reinforcement learning reward signals

Since the suggestion by Tolman (1948) that both rodents and humans create cognitive maps during navigation, the specifics of how navigators learn about their environment has been mired in debate. One facet of this debate is whether or not the creation of cognitive maps - also known as allocentric navigation - involves reinforcement learning. Here, we demonstrate a role for reinforcement learning during allocentric navigation using event-related brain potentials (ERPs). In the present experiment, participants navigated in a virtual environment that allowed the use of three different navigation strategies (allocentric, egocentric-response, & egocentric-cue), in which their goal was to locate and remember a hidden platform. Following the navigation phase of the experiment, participants were shown "cue images" representative of the three navigation strategies. Specifically, we examined whether or not these passively learned strategy images elicited a reward positivity - an ERP component associated with reinforcement learning and the anterior cingulate cortex. We found that when allocentric navigators were shown previously learned cues predicting the goal location a reward positivity was elicited. The present findings demonstrate that allocentric navigational cues carry long-term value after navigation and lend support to the claim that reinforcement learning plays a role in the acquisition of allocentric navigation and thus the generation of cognitive maps.