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

这个项目考察了除了巩固新的学习，睡眠是否有助于清除最近感知和认知活动中不想要的残留物。传统的学习观点认为，新的记忆会在一段时间内摇摇欲坠，但很快就会巩固，对健忘剂和新学习的干扰产生抵抗力(McGaugh，2000；Wixted，2004)。然而，最近的理论化(StickGold&Walker，2013)坚持认为，记忆巩固不是刚刚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，根据生物体目标导向的需求而量身定做的。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：只有在情感上突出的或值得记住以备将来使用的记忆，才会被同化到大脑不断演变的知识版图中。在这里，我们想知道，在这个介于工作记忆和长期记忆之间的无人区(即工作记忆和长期记忆之间；此后称为IBM)，不想要的记忆会发生什么？这个项目的目标是确定睡眠除了稳定和吸收有用的记忆外，是否还清除了不想要的记忆以重置系统，以便第二天重新开始。离线的证据表明，睡眠依赖的记忆巩固是实质性的，显示出各种变革性的结果，包括对健忘剂的弹性增加，增强的可获得性，自发的恢复，潜在结构的提取，以及与现有知识的整合。相比之下，内存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到的信息。我们的前提是，不想要的剩余物主要包括最近由感知、表达或基于图像的体验唤起的长期记忆的挥之不去的激活。这种激活积累了一天中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的行为，也许只要我们保持清醒。这些持久激活的副产品正是主动遗忘机制将摆脱的。为了检验这一假设，我们探索了语言暴露和/或练习和使用留下的记忆痕迹的演变。语言提供了一个理想的试验床，因为同一语言事件可能会引发人们不一定想要保持的挥之不去的影响，以及依赖睡眠的离线巩固单元化的新信息。我们已经有了索引这两种影响的语言表现指标，在这个阶段，通过睡眠巩固新词汇知识的过程已经有了很好的记录。工作包1考察了新词形式记忆的命运，以及它们巩固或清理的可能性。Work Package 2提供了多个测试，以确定睡眠是否通过消除挥之不去的痕迹来消除过去。我们的试点数据(图标签6)表明确实是这样。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，以评估睡眠不足对记忆巩固和同时清理的影响。如果老年人在巩固问题上表现出清理障碍，清理减少可能是导致认知能力逐渐下降的因素之一，而认知衰退是正常衰老的特征。我们的实验聚焦于语言记忆，以探索睡眠是否会重置我们所说的IBM。积极的发现将提供概念证明，在教育、工作模式、体育科学、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.