Experience-dependent phase-reversal of hippocampal neuron firing during REM sleep

Learned material content and acquisition level modulate cerebral reactivation during posttraining rapid-eye-movements sleep

“…Accordingly in humans, post-training modifications of sleep parameters are also observed after conditioning in babies, but only when the stimulus-response association had been successfully learned (Paul and Dittrichova, 1975). At the systems level, experience-dependent replay of neuronal activity during REM sleep has been already demonstrated in animals (Poe et al, 2000;Louie and Wilson, 2001), but not yet proven behaviorally relevant since the link between the performance and the ensuing neural pattern during sleep has never been demonstrated (Peigneux et al, 2001). Here, we provide the first evidence that the strength of rCBF reactivation during post-training REM sleep depends on prior learning level in humans.…”

The hippocampal debate: are we asking the right questions?

“…Intriguingly, replay of familiar and novel memories occur at different phases of the theta rhythm: novel memories are replayed at the peak of REM-theta, while familiar memories are replayed at the trough [164]. As pointed out by Poe et al [164], when taken with data showing that LTP is stronger at the peak than at the trough of theta [81], this may be a mechanism for strengthening new memories and erasing old ones in hippocampus.…”

“…There is also some evidence for replay of representations during REM sleep as well [96,161,164]. Intriguingly, replay of familiar and novel memories occur at different phases of the theta rhythm: novel memories are replayed at the peak of REM-theta, while familiar memories are replayed at the trough [164].…”

Where is the classic interference theory for sleep and memory?

“…These include the integration of recently consolidated information with past experiences and knowledge, reorganization, reconsolidation following reactivation of a memory, translocation, and even erasure of network strengths thus weakening memory representations, with which sleep has already been associated (Crick & Mitchison 1983;Hasselmo 1999;Poe et al 2000;Walker et al 2003a). As our understanding of memory-stage development increases, so too should our curiosity regarding the distinct contributions that both wake and sleep may offer.…”

“…At a systems level, several studies have demonstrated that the collective neuronal firing patterns recorded in the hippocampus of rats during the performance of spatial maze running are replayed during subsequent SWS and REM sleep episodes, albeit at relatively different temporal speeds (Louie & Wilson 2001;Poe et al 2000;Skaggs & McNaughton 1996;Wilson & McNaughton 1994). In a similar paradigm, Dave and Margoliash (2000;Dave et al 1998) have shown that waking patterns of premotor activity during song learning in the zebra finch, are replayed in a temporally and structurally similar manner during sleep.…”