Does sleep flush out the unwanted leftovers of recent cognitive activities?

这个项目研究睡眠是否有助于清除最近的感知和认知活动中不需要的残余，以及巩固新的学习。传统的学习观点认为，新记忆在一段时间内是不稳定的，但很快就会巩固，对健忘因素和新学习的干扰产生抵抗力（McGaugh, 2000; Wixted, 2004）。然而，最近的理论（Stickgold & Walker, 2013）坚持认为，记忆巩固不是刚才描述的统一和不分青红皂白的过程，而是高度选择性和适应性的，根据生物体的目标导向需求量身定制。睡眠及其相关的神经生理状态，是“记忆分类”过程的主要载体：只有那些情感上突出的、或值得记住以备将来使用的记忆，才会被大脑不断进化的知识景观所同化。在这里，我们要问的是，无用的记忆会发生什么，它们也开始于这片介于记忆之间的无人区（即，在工作记忆和长期记忆之间；从此，IBM）？这个项目的目的是确定除了稳定和吸收有用的记忆外，睡眠是否还能清除无用的记忆，从而重置系统，以便第二天重新开始。离线，睡眠依赖性记忆巩固的证据是大量的，显示了各种变革性的结果，包括对遗忘剂的恢复能力增强，可访问性增强，自发恢复，提取底层结构以及与现有知识的整合。相比之下，记忆清理的存在尚未得到证实。我们认为这在很大程度上是因为研究人员认为他们可以强迫学习者忘记新学的信息。我们的前提是，不想要的剩饭剩菜主要是由最近由感知、表达或基于图像的经验唤起的长期记忆的挥之不去的激活组成的。这种激活在一天的过程中积累了特定记忆的参与记录。因此，这可能会潜移默化地影响我们在接下来的几个小时里，甚至在我们保持清醒的时候的行为。这些持续激活的副产品正是主动遗忘机制所要摆脱的。为了验证这一假设，我们探索了语言接触和/或实践和使用留下的记忆痕迹的演变。语言提供了一个理想的测试平台，因为同样的语言事件既可以引起人们不一定想要保持的挥之不去的影响，也可以引起依赖睡眠的离线统一新信息的巩固。我们已经有了将这两种影响都编入索引的语言表现衡量标准，并且在这个阶段，通过睡眠巩固新词汇知识的行为已经得到了很好的记录。工作包1考察了新词形记忆的命运及其巩固或清理的潜力。工作包2提供了多个测试，用于测试睡眠是否确实通过清除残留的痕迹来清理石板。我们的试点数据（图TA6）表明确实如此。最后，工作包3侧重于高危人群，即老年人和睡眠呼吸暂停患者，以评估睡眠质量差同时对记忆巩固和清理的影响。如果老年人在巩固问题上表现出清理能力受损，清理能力下降可能是正常衰老特征的认知能力逐渐下降背后的因素之一。我们的实验集中在语言记忆上，以探索睡眠是否会重置我们所说的IBM。积极的发现将提供一个概念的证明，在教育、工作模式、运动科学、老龄化、延长军事任务和神经认知康复等领域具有强大的应用潜力。

This project examines whether sleep helps flush out unwanted leftovers of recent perceptual and cognitive activities in addition to consolidating new learning.Traditional views of learning assume that new memories are shaky for a while, but soon consolidate, becoming resistant to amnestic agents and interference from new learning (McGaugh, 2000; Wixted, 2004). Recent theorizing (Stickgold & Walker, 2013), however, insists that memory consolidation is not the uniform and indiscriminate process just described, but is instead highly selective and adaptive, tailored to the goal-directed needs of the organism.Sleep, with its associated neurophysiological states, is the prime vehicle for a "memory triage" process: only memories that are emotionally salient, or worth remembering for future use, get assimilated into the brain's landscape of ever evolving knowledge. Here we ask what happens to unwanted memories, which also start off in this no man's land of in between memory (i.e., between working memory and long-term memory; henceforth, IBM)? The goal of this project is to determine whether in addition to stabilizing and assimilating useful memories, sleep also cleans the slate of unwanted memories to reset the system, in order to start afresh the next day.Evidence for offline, sleep-dependent memory consolidation is substantial, showing a variety of transformative results, including increased resilience to amnestic agents, enhanced accessibility, spontaneous recovery, extraction of underlying structures, and integration with existing knowledge. In contrast, the existence of memory clean-up has not yet been substantiated. We suggest this is largely because researchers thought they could just force learners to forget newly learnt information.Our premise is that unwanted leftovers mostly comprise the lingering activation of long-term memories recently evoked by perceptual, expressive, or imagery-based experience. This activation accumulates records of involvement of a given memory over the course of a day. As such, this could influence rather insidiously how we behave during the next few hours, and perhaps for as long as we remain awake. These persisting activation byproducts are precisely what an active forgetting mechanism would get rid of.To test this hypothesis, we explore the evolution of memory traces left by language exposure and/or practice and use. Language provides an ideal testbed, as the same linguistic event can provoke both lingering effects that one would not necessarily want to keep and sleep-dependent offline consolidation of unitized new information. We already have linguistic performance measures that index both kinds of effects, and the consolidation of new lexical knowledge through sleep is well documented at this stage.Work Package 1 examines the fate of memories for novel word forms and their potential for either consolidation or clean-up. Work Package 2 provides multiple tests of whether sleep does clean the slate by removing lingering traces. Our pilot data (Fig. TA6) suggest that it does. Finally, Work Package 3 focuses on at-risk populations, namely older adults and sleep apnoea patients, to evaluate the impact of poor sleep on both memory consolidation and clean-up simultaneously. If older adults show impaired clean-up on top of consolidation problems, reduced clean-up could be one of the factors behind the gradual cognitive decline that characterizes normal aging.Our experiments focus on language memories to explore whether sleep resets what we have called IBM. Positive findings will provide a proof of concept, with a strong potential for applications in domains as varied as education, work patterns, sports science, aging, extended military missions, and neurocognitive rehabilitation.