Hippocampal sharp-wave ripples in waking and sleeping states

- Hippocampal SWRs contain neural activity reactivations in both waking and sleeping.
- SWRs in waking and sleeping entail distinct features, particularly replay accuracy.
- Features of awake SWRs suggest a role in rapid navigational planning.
- Features of sleep SWRs suggest a role in gradual memory consolidation.

Waking and sleeping states are privileged periods for distinct mnemonic processes. In waking behavior, rapid retrieval of previous experience aids memory-guided decision making. In sleep, a gradual series of reactivated associations supports consolidation of episodes into memory networks. Synchronized bursts of hippocampal place cells during events called sharp-wave ripples communicate associated neural patterns across distributed circuits in both waking and sleeping states. Differences between sleep and awake sharp-wave ripples, and in particular the accuracy of recapitulated experience, highlight their state-dependent roles in memory processes.