It has been demonstrated in different species and types of memories that a night of sleep improves memory consolidation of recent acquired information. Furthermore, even a 6min-nap benefits memory storage. It has been proposed that neocortical slow oscillations (0.5-1 Hz) during Non Rapid Eye Movement sleep (NREM), orchestrate the hippocampal-cortical dialog, promoting memory reactivation in the hippocampus through the hippocampal sharp wave ripples, together with the thalamocortical spindles, which participate in the induction of durable plastic changes in the neocortex.
Recently, sleep has been proposed as a tool to improve education. However, to implement that in a school setting, more research has to be conducted studying the effects of short naps in memory processes as well as the mechanisms involved. Here, we studied the effect of a short nap on memory persistence. Participants learned 5 pairs of nonsense syllables on Day 1 and slept for 18.7 min while a polysomnography was performed, or they remained awake. They were finally tested on Day 8. We found that sleeping 18.7 min after learning the task improves memory persistence and that slow oscillations are involved in memory consolidation of the syllable pairs. Moreover, as NREM stage 2 is the predominant sleep stage scored in these short naps, almost all slow oscillations detected correspond to K-complexes. Thus, we discuss the possible role of these complexes in the hippocampal-cortical dialog.