Department of Neuroendocrinology, University of Lübeck, Lübeck, Germany.
Prog Brain Res. 2011;193:93-110. doi: 10.1016/B978-0-444-53839-0.00007-7.
Slow-wave sleep (SWS) facilitates the consolidation of hippocampus-dependent declarative memory. Based on the standard two-stage memory model, we propose that memory consolidation during SWS represents a process of system consolidation which is orchestrated by the neocortical <1Hz electroencephalogram (EEG) slow oscillation and involves the reactivation of newly encoded representations and their subsequent redistribution from temporary hippocampal to neocortical long-term storage sites. Indeed, experimental induction of slow oscillations during non-rapid eye movement (non-REM) sleep by slowly alternating transcranial current stimulation distinctly improves consolidation of declarative memory. The slow oscillations temporally group neuronal activity into up-states of strongly enhanced neuronal activity and down-states of neuronal silence. In a feed-forward efferent action, this grouping is induced not only in the neocortex but also in other structures relevant to consolidation, namely the thalamus generating 10-15Hz spindles, and the hippocampus generating sharp wave-ripples, with the latter well known to accompany a replay of newly encoded memories taking place in hippocampal circuitries. The feed-forward synchronizing effect of the slow oscillation enables the formation of spindle-ripple events where ripples and accompanying reactivated hippocampal memory information become nested into the single troughs of spindles. Spindle-ripple events thus enable reactivated memory-related hippocampal information to be fed back to neocortical networks in the excitable slow oscillation up-state where they can induce enduring plastic synaptic changes underlying the effective formation of long-term memories.
慢波睡眠（SWS）有助于巩固海马体依赖的陈述性记忆。基于标准的两阶段记忆模型，我们提出，SWS 期间的记忆巩固代表了一个系统巩固的过程，该过程由新皮层<1Hz 的脑电图（EEG）慢波协调，并涉及新编码的表示的再激活及其随后从临时海马体到新皮层的长期存储位置的重新分配。事实上，通过缓慢交替经颅电流刺激在非快速眼动（非 REM）睡眠期间诱导慢波明显改善了陈述性记忆的巩固。慢波在时间上将神经元活动分组为强烈增强神经元活动的上状态和神经元沉默的下状态。在正向传出作用中，这种分组不仅发生在新皮层中，也发生在与巩固相关的其他结构中，即产生 10-15Hz 纺锤波的丘脑，以及产生尖波-涟漪的海马体，后者众所周知伴随着新编码的记忆在海马体回路中的重播。慢波的前馈同步效应使得能够形成纺锤波-涟漪事件，其中涟漪和伴随的重新激活的海马体记忆信息嵌套到纺锤波的单个波谷中。因此，纺锤波-涟漪事件使重新激活的与记忆相关的海马体信息能够反馈到兴奋性慢波上状态的新皮层网络中，在该状态下，它们可以诱导持久的可塑性突触变化，从而有效地形成长期记忆。
