REM sleep and memory.

Memory consolidation, a process which stabilizes recently acquired information into long-term storage, is thought to be optimized during sleep. Although recent evidence indicates that non-rapid-eye movement sleep (NREMs) is directly involved in memory consolidation, the role of rapid-eye movement sleep (REMs) in this process has remained controversial due to the extreme difficulty in experimentally isolating neural activity during REMs. Using a combination of electrophysiological recording and optogenetic techniques, recent work demonstrated for the first time that neural activity occurring specifically during REMs is required for spatial and contextual memory consolidation. Identifying the underlying mechanisms behind these observations, precisely how they translate to humans, and clarifying the extent of REMs' role in other modalities of memory are important challenges of future research with implications for human health.