Brain Gene Expression During REM Sleep Depends on Prior Waking Experience

Abstract

In most mammalian species studied, two distinct and successive phases of sleep, slow wave (SW), and rapid eye movement (REM), can be recognized on the basis of their EEG profiles and associated behaviors. Both phases have been implicated in the offline sensorimotor processing of daytime events, but the molecular mechanisms remain elusive. We studied brain expression of the plasticity-associated immediate-early gene (IEG) zif-268 during SW and REM sleep in rats exposed to rich sensorimotor experience in the preceding waking period. Whereas nonexposed controls show generalized zif-268 down-regulation during SW and REM sleep, zif-268 is upregulated during REM sleep in the cerebral cortex and the hippocampus of exposed animals. We suggest that this phenomenon represents a window of increased neuronal plasticity during REM sleep that follows enriched waking experience.

Impaired Off-Line Consolidation of Motor Memories After Combined Blockade of Cholinergic Receptors During REM Sleep-Rich Sleep

“…Whereas non-REM sleep is characterized by diminished activity of such genes and a greatly reduced ability to induce synaptic long-term potentiation, REM sleep provides a more adequate milieu of neurotransmitters and modulators for synaptic plastic changes (Ribeiro and Nicolelis, 2004;Bramham and Srebro, 1989). Ribeiro et al (Ribeiro et al, 1999 revealed an increased expression of the immediate early genes arc and zif-268 during REM sleep after induction of long-term potentiation during prior wakefulness. Importantly, regulation of plasticity-related early genes depends strongly on the cholinergic receptor activation (von der Kammer et al, 1998(von der Kammer et al, , 2001Teber et al, 2004) and, here, blocking these receptors interfered likely with transcriptional changes required for long-term memory storage.…”

Elevated Sleep Spindle Density after Learning or after Retrieval in Rats

“…We found a time window during SWS ϳ2 h after the rat learned the odorreward contingency when the noradrenergic neurons of the locus ceruleus, which are usually quiescent during SWS, show a surge of activity that is never seen in animals that have not been in the learning situation (Sara et al, 2005). Learning-related delayed release of noradrenaline in forebrain neurons (Tronel et al, 2004), which are potentially engaged in reactivation during sleep, would serve as an effective signal or "molecular switch" for gene expression during a subsequent REM episode (Ribeiro et al, 1999;Cirelli and Tononi, 2000).…”

Effects of Skilled Training on Sleep Slow Wave Activity and Cortical Gene Expression in the Rat

“…14 Ribeiro and colleagues found that the exposure to a new environment for 3 hours 15 results in the immediate cortical and hippocampal induction, during waking, of plasticity-related gene zif-268, 16 followed by its downregulation during NREM sleep, and then again by its increased expression during REM sleep (relative to NREM sleep). Intriguingly ~ 3 min of NREM sleep were enough to downregulate waking-induced zif-268 expression, and ~ 2 min of REM sleep were sufficient to detect its selective reinduction, even if both NREM and REM rats were awake during the last 30 min before sacrifice.…”