The role of prefrontal spatial coding in supporting a contextual association task

The medial prefrontal cortex (mPFC) has a broad role in cognitive flexibility and executive function, as well as long-term memory consolidation. These distinct functions are reconciled by the mPFC’s role in context-dependent decision making, which requires the evaluation and selection of representations that are relevant for a particular goal.The hippocampus and mPFC interact via direct and indirect pathways. Coordinated activity between these regions occurs both during hippocampal theta and sharp-wave ripples (SWRs) and is correlated with performance during tasks that rely on spatial information for correct decisions. The mPFC has been shown to encode spatial information and mPFC assemblies reactivate during sleep coincidentally with hippocampal SWRs. Moreover, the mPFC has recently been shown to replay temporally organized spatial sequences in well-trained animals during awake immobility while performing a spatial rule-switching task. Our work aims to identify the emergence of spatial coding and trajectory replay in the mPFC and correlate this with performance in naive animals.We use 32-tetrode microdrives to record from the hippocampus and mPFC while rats learn to associate a food with a reward location in an 8-arm maze. Two paired associations are learned in parallel. To find the reward, the rats must flexibly adapt their behavior based on which food is presented, i.e. which “context” they find themselves in. During the acquisition of the behavioral data, we observed a jump in performance after 6-7 days of training. This shift may coincide with the emergence or refinement of spatial representations and trajectory replay in the mPFC.