to guide future actions, as well as planning [7,46,54,55]. Hippocampal replay during awake SWRs comprises reactivation of place cell sequences in forward and reverse temporal order, as well as novel shortcut sequences, suggestive of a diverse role in reinforcement learning, planning and prospective decision making [7,42–46]. Critically, awake SWRs have been shown to be necessary for spatial learning [56], establishing that awake hippocampal replay is required for memory processes. But until recently, whether or how awake hippocampal replay engages other brain regions, in particular PFC, was still unclear. It has now been shown that awake SWRs are associated with coherent reactivation of behaviorally concordant information in the hippocampal-PFC network (Figure 2). This strong coordination results in structured reactivation of representations related to ongoing experience, and also reflects reactivation of coordinated hippocampal-cortical activity during theta oscillations [31]. SWRs and theta oscillations mark distinct network states during distinguishable behavioral epochs, and are associated with unique modes of hippocampal information processing. Thus, this body of evidence establishes that theta oscillations and awake SWRs represent distinct mechanisms for communication between these distant brain structures.
