State Dependent Aspects of Cognition

描述（由申请人提供）：在过去的十年里，我们对睡眠依赖性记忆巩固的理解有了戏剧性的增长，它从一个普遍不被认可（或者最多被忽视）的概念，变成了记忆和睡眠研究人员普遍接受的原则，甚至在本科心理学教科书中也有发现。这项工作在睡眠和记忆功能之间建立了牢固的联系。但考虑到睡眠和记忆的复杂性，它们都包含多个阶段和子类型，即使是这种现象的最基本特征也不清楚。哪些类型的记忆在睡眠中得到巩固？巩固的哪些部分发生在睡眠中？哪个睡眠阶段调节这种巩固？什么样的生理过程是睡眠依赖性巩固的基础？迄今为止，大多数研究都试图将特定类别的记忆的巩固分配到离散的睡眠阶段，例如程序记忆的巩固分配到快速眼动睡眠或陈述性记忆的巩固分配到慢波睡眠（SWS）。但这种简单的二分法的例外情况几乎超过了支持它的研究。这里提出的几项新研究，使我们提出了一个统一的睡眠依赖记忆巩固假说，来描述睡眠阶段如何促进记忆巩固。我们认为，睡眠在记忆处理中扮演的角色比之前认为的更微妙，睡眠阶段有选择性地与特定的记忆类型无关，而是与记忆巩固过程的特定组成部分有关。具体来说，我们提出，SWS稳定了最近获得的陈述性和程序性记忆，而快速眼动和第二阶段非快速眼动睡眠随后增强了它们，选择性地强化了它们最有价值的成分，并将它们整合到预先存在的存储信息网络中。正如我们将在下面展示的那样，这个新的假设与越来越多的关于睡眠依赖的记忆功能巩固的文献是一致的，并且得到了我们初步结果的有力支持。这些新的结果，与统一记忆巩固假说相一致，将睡眠和记忆的研究从经典记忆巩固（即稳定）的讨论，推进到更强大、更有价值的睡眠依赖记忆增强形式的领域，即(1)扩大存储记忆的神经网络，(2)从大量编码信息中提取模式和规则，(3)将它们与其他信息整合，将较老的记忆转化为丰富的语义网络，从而有选择地增强记忆中对生物体最有价值的那些方面。在下面的研究计划中，我们将通过综合研究来验证我们统一的睡眠依赖记忆巩固假说，这些研究旨在确定(1)睡眠期间巩固的记忆类型，(2)睡眠阶段与它们的稳定和各种形式的增强（例如整合，规则提取）相关，以及(3)这些过程的生理基础。与公共健康相关：西方社会越来越缺乏睡眠，这一点在美国表现得最为明显。在美国，人们普遍认为，睡眠不足的唯一后果是困倦，这是可以通过努力或药物克服的，周末睡个好觉可以完全扭转周中睡眠不足带来的任何有害影响。但现在很清楚，睡眠在稳定和增强最近形成的记忆方面起着至关重要的作用，睡眠不足会导致这些潜在好处的不可挽回的丧失。我们现在提出了一个统一的睡眠依赖记忆巩固假说，提出深的慢波睡眠稳定了最近获得的记忆，而快速眼动睡眠和较轻的第二阶段非快速眼动睡眠随后增强了这些记忆，选择性地强化了它们最有价值的部分，并将它们整合到预先存在的存储信息网络中。

DESCRIPTION (provided by applicant): The last decade has seen a dramatic increase in our understanding of sleep-dependent memory consolidation, moving it from a generally discredited (or at best ignored) concept to a largely accepted tenet among both memory and sleep researchers, even found in undergraduate psychology textbooks. This work has established a firm connection between sleep and memory function. But given the complexity of both sleep and memory, each of which comprise multiple stages and subtypes, even the most basic characterizations of this phenomenon remain unclear. Which types of memory are consolidated during sleep? Which components of consolidation occur during sleep? Which sleep stages mediate this consolidation? And what physiological processes underlie sleep-dependent consolidation? To date, most studies have sought to assign consolidation of particular classes of memory to discrete sleep stages, for example consolidation of procedural memories to REM sleep or declarative memories to slow wave sleep (SWS). But exceptions to this simple dichotomy come close to outnumbering supporting studies. Several new studies, presented here, lead us to now propose a unified sleep-dependent memory consolidation hypothesis, to describe how sleep stages contribute to memory consolidation. We propose that sleep plays a more nuanced role in memory processing than previously considered, with sleep stages being selectively involved not with specific memory types, but with specific components of the memory consolidation process. Specifically, we propose that SWS stabilizes recently acquired declarative and procedural memories, while REM and Stage 2 nonREM sleep subsequently enhance them, selectively reinforcing their most valuable components and integrating them into preexisting networks of stored information. As we will show below, this new hypothesis is consistent with the growing literature of sleep-dependent consolidation across a range of memory functions, and is strongly supported by our Preliminary Results. These new results, in concert with the unified memory consolidation hypothesis, move the study of sleep and memory beyond a discussion of classical memory consolidation (i.e., stabilization), into the realm of more powerful and valuable forms of sleep-dependent memory enhancement that (i) enlarge the neural networks in which memories are stored,(ii) extract patterns and rules from large bodies of encoded information and (iii) integrate them with other, older memories into rich semantic networks, thereby selectively enhancing those aspects of memories of greatest value to the organism. In the research program proposed below, we will test our unified sleep-dependent memory consolidation hypothesis through integrated studies designed to identify (1) the types of memories consolidated during sleep, (2) the sleep stage correlates of both their stabilization and their various forms of enhancement (e.g. integration, rule extraction) and (3) the physiological substrates of these processes. PUBLIC HEALTH RELEVANCE: Western society has become increasingly sleep deprived, and nowhere is this more true than in the United States, where there is a popular belief that the only consequence of sleep deprivation is sleepiness which can be overcome with effort or drugs, and that a good night's sleep on the weekend can completely reverse any deleterious effects of mid-week deprivation. But it is now clear that sleep plays a critical role in the stabilization and enhancement of recently formed memories, and that sleep loss can cause the irrevocable loss of these potential benefits. We now put forward a unified sleep-dependent memory consolidation hypothesis, proposing that deep, slow wave sleep stabilizes recently acquired memories, while REM sleep and lighter, Stage-2 nonREM sleep subsequently enhance these memories, selectively reinforcing their most valuable components and integrating them into preexisting networks of stored information.