An assembly-line model of sleep, dreaming and memory enhancement: investigating the coordinated roles of REM and nonREM sleep in human memory consolidation

快速眼动(REM)和非快速眼动(NREM)睡眠都积极地促进记忆的改善，某些振荡事件，如睡眠纺锤波(11-16赫兹脑电活动的爆发)，是这种活动的可靠生物标志物。关于做梦是否在记忆中发挥作用，尤其是新记忆的梦境重播是否也构成这样的生物标记物，证据更加混杂。我们最近复制了一项发现，即非快速眼动睡眠和快速眼动睡眠以互补的方式影响记忆，更重要的是，首次表明非快速眼动睡眠纺锤波、快速眼动睡眠时间以及做梦时间和内容都是相互关联的衡量标准。这些相关性在第三个睡眠周期中更明显，这表明这是一个特别有利于记忆可塑性的时期，这一现象以前只在啮齿动物身上表现出来。作为新的发现，这些NREM-REM做梦的相关性需要被复制，扩展到其他改善记忆的睡眠指标，并使用工具进行评估，从而得出因果关系的结论。这项拟议的研究旨在通过仔细复制和使用经过验证的靶向记忆重新激活(TMR)方法来增强睡眠期间的记忆，从而实现这些目标。对于TMR，音调在任务中呈现，然后在NREM睡眠中再次呈现；这些声音可能重新激活了在任务学习过程中形成的神经回路。我们将通过在NREM睡眠中呈现与任务相关的音调以及测量NREM、REM和做梦措施是如何改变的来加强学习。在一个典型的实验中，我们的任务将在虚拟现实(VR)环境中完成，并将涉及导航迷宫。我们将评估，在非快速眼动睡眠中，纺锤体活动是否增加；在快速眼动睡眠中，眼球运动是否发生变化；以及在梦报告中，是否出现VR任务回放。如果睡眠周期3是记忆处理的特权窗口，那么在周期3(与周期2或4)播放TMR声音的受试者的任务改进和睡眠/梦的变化应该是最大的。这项研究将对研究睡眠和记忆、做梦或TMR的人感兴趣，并应该为睡眠如何控制记忆存储提供洞察力。它将对展示定时和刺激睡眠如何优化记忆，从而更精确地增强学习具有特别的相关性。这些发现也可能有助于解释做梦是否以及如何与记忆有关，即通过澄清做梦与睡眠纺锤波的关系，以及做梦是否重演新学习的元素。因此，这项工作可能会导致对记忆和睡眠的更深刻理解，并支持越来越多的加拿大人通过获得更多睡眠来改善他们的认知功能。这种类型的研究可能导致基于睡眠的方法的发展，以增强、优化和恢复记忆，并在面临与年龄或疾病相关的衰退时保护记忆。

Both rapid eye movement (REM) and nonREM (NREM) sleep actively contribute to memory improvement and certain oscillatory events, such as sleep spindles (bursts of 11-16 Hz EEG activity), are reliable biomarkers of this activity. Evidence is more mixed as to whether dreaming plays a role in memory and, especially, whether dream replays' of new memories also constitute such a biomarker. We recently replicated findings that NREM and REM sleep influence memory in a complementary fashion and, more importantly, showed for the first time that NREM sleep spindles, amount of REM sleep and dreaming length and content are all inter-correlated measures. These correlations were preferentially strong for the third sleep cycle, suggesting that it is a time particularly conducive to memory plasticity, a phenomenon previously shown only for rodents. As new discoveries, these NREM-REM-dreaming correlations need to be replicated, extended to other sleep measures of memory improvement, and evaluated with tools that permit drawing conclusions about cause and effect. The proposed research aims to achieve these objectives by careful replication and by enhancing memory during sleep using a validated, targeted memory reactivation (TMR), method. With TMR, tones are presented during a task and then again during NREM sleep; the sounds presumably reactivate neural circuits that were formed during task learning. We will enhance learning by presenting task-associated tones in NREM sleep and measuring how NREM, REM and dreaming measures are altered. In a typical experiment, our task will be completed in a virtual reality (VR) setting and will involve navigating a maze. We will assess, in NREM sleep, if spindle activity increases; in REM sleep, if eye movements change; and, in dream reports, if VR task replays appear. If sleep cycle 3 is a privileged window for memory processing, then task improvement and sleep/dream changes should be greatest for subjects to whom TMR sounds are played during cycle 3 (vs. during cycles 2 or 4).The research will be of interest to persons studying sleep and memory, dreaming or TMR and should provide insights into how sleep controls memory storage. It will have a particular relevance for showing how timing and stimulating sleep episodes can optimize memory and thus enhance learning with greater precision. Findings may also help explain if and how dreaming is implicated in memory, i.e., by clarifying its relationship to sleep spindles and whether it replays elements of new learning. Thus, the work may lead to a more profound understanding of both memory and sleep and support a growing outreach to Canadians to improve their cognitive functioning by getting more sleep. This type of research may lead to the development of sleep-based methods for enhancing, optimizing and rehabilitating memory and in protecting it in the face of age-related or illness-related decline.