About Sleep's Role in Memory

Abstract

Over more than a century of research has established the fact that sleep benefits the retention of memory. In this review we aim to comprehensively cover the field of "sleep and memory" research by providing a historical perspective on concepts and a discussion of more recent key findings. Whereas initial theories posed a passive role for sleep enhancing memories by protecting them from interfering stimuli, current theories highlight an active role for sleep in which memories undergo a process of system consolidation during sleep. Whereas older research concentrated on the role of rapid-eye-movement (REM) sleep, recent work has revealed the importance of slow-wave sleep (SWS) for memory consolidation and also enlightened some of the underlying electrophysiological, neurochemical, and genetic mechanisms, as well as developmental aspects in these processes. Specifically, newer findings characterize sleep as a brain state optimizing memory consolidation, in opposition to the waking brain being optimized for encoding of memories. Consolidation originates from reactivation of recently encoded neuronal memory representations, which occur during SWS and transform respective representations for integration into long-term memory. Ensuing REM sleep may stabilize transformed memories. While elaborated with respect to hippocampus-dependent memories, the concept of an active redistribution of memory representations from networks serving as temporary store into long-term stores might hold also for non-hippocampus-dependent memory, and even for nonneuronal, i.e., immunological memories, giving rise to the idea that the offline consolidation of memory during sleep represents a principle of long-term memory formation established in quite different physiological systems.

Autonomic activity during sleep predicts memory consolidation in humans

“…Data are reported as mean ± SD. P = 0.92, η 2 p < 0.01] or Novel [F (1,53) = 0.87, P = 0.36, η 2 p = 0.02] condition. Interestingly, we noted that compared with baseline performance, the QW group showed a decrease in performance in the Primed condition [t (20) = −2.63, P = 0.02], an increase in performance in the Repeated condition [t (20) = 2.06, P = 0.05], and no difference in the Novel condition [t (20) = −0.09, P = 0.93].…”

“…sleep | heart rate variability | memory | consolidation | vagal activity S leep has been shown to facilitate the transformation of recent experiences into stable, long-term memories (i.e., consolidation), and specific electrophysiological sleep features have been implicated in this process (1). For example, minutes spent in slow wave sleep (SWS) and the number of sleep spindles [transient neural events in nonrapid eye movement (NREM) sleep, [12][13][14][15] in a posttraining sleep period correlate with the magnitude of explicit memory improvement [e.g., conscious, episodic memories (2,3)].…”

Qualidade do sono e cronotipo de estudantes de enfermagem

“…(16) These findings, together with the results found in the present study are disturbing because sleeping is associated with different modes of memory processing, favoring its consolidation and the recovery of stimuli required at the moment of wakefulness. (17) The lack of sleep may interfere in the process of consolidating students' knowledge and in the quality of trained professionals.…”

Optogenetic activation of septal cholinergic neurons suppresses sharp wave ripples and enhances theta oscillations in the hippocampus

“…State changes can occur both during sleep and in the waking animal and are instrumental in affecting local circuit computation that supports various functions, including attention, learning, memory, and action (3)(4)(5). The septo-hippocampal cholinergic system has been hypothesized to play a critical role in setting network states in the limbic system (4,6).…”