The role of dreaming in REM and NREM sleep-dependent memory functions

现在有强有力的证据表明，快速眼动睡眠和非快速眼动睡眠对线下记忆的改善有不同的贡献，例如，快速眼动睡眠对情绪记忆的贡献，而非快速眼动睡眠对陈述性记忆的贡献。尽管最近大量的研究表明，梦到一项学习任务预示着以后这项任务的进步，但还没有研究确定快速眼动梦和非快速眼动梦是否与不同的记忆系统有关。尽管有充分的证据表明REM/NREM梦的特征与不同的记忆类型之间存在相似之处，即REM梦比NREM梦在情感上更丰富，而NREM梦在本质上更像思考。快速眼动梦的情感本质特别令人感兴趣，因为在学习任务之前、期间或之后(清醒时)仅仅呈现情感刺激就可以改善该任务的后来记忆--无论情感刺激是积极的还是消极的，或者在概念上与任务无关。以类似的方式，快速眼动梦境情绪可能有助于记忆新的信息，这些信息在时间上非常接近地被重新激活。这项拟议的研究旨在：1)确定关于学习任务的梦是否与该任务的线下改进相关；2)评估REM梦和NREM梦是否分别与情绪和陈述性记忆任务有不同的关联；3)测试REM梦情绪的实验性强化是否会增强非情绪任务的记忆。健康的受试者将参加一系列研究，这些研究使用已知的诱发REM和NREM睡眠依赖记忆效应的方案，并对方案进行修改，以包括对REM和NREM梦的标准化评估。睡眠前的学习任务将在第二天重新测试，而中间的睡眠时间则在实验室进行监测和量化。对情绪强度和概念内容的梦境评分预计与一夜之间学习的改善有关，即使在统计上去除了REM/NREM睡眠和改善之间的相关性时也是如此。这些发现将有助于更广泛地揭示做梦的功能和记忆的机制，并可能为改善记忆的策略提供见解。

Strong evidence now shows that REM and NREM sleep contribute differentially to offline improvements in memory, e.g., REM sleep to emotional memory and NREM sleep to declarative memory. And although a recent surge of studies suggests that dreaming about a learning task predicts later improvement on this task, no studies have yet determined if REM and NREM dreaming are implicated in different memory systems. This, despite ample evidence of parallels between REM/NREM dreaming features and different memory types, i.e., REM dreaming is more emotionally rich than NREM dreaming, while the latter is more thoughtlike in nature. The emotional nature of REM dreaming is of particular interest because the mere presentation of emotional stimuli prior to, during, or following a learning task (when awake) improves later memory for that task--regardless of whether the emotional stimuli are positive or negative or conceptually unrelated to the task. In a similar manner, REM dream emotions may facilitate memory for new information that is reactivated in close temporal proximity. The proposed research aims to: 1) determine if dreaming about a learning task is correlated with offline improvement on that task, 2) assess if REM and NREM dreaming are differentially associated with emotional and declarative memory tasks respectively, and 3) test whether the experimental intensification of REM dream emotions will enhance memory for a non-emotional task. Healthy subjects will participate in a series of studies that use protocols known to induce REM and NREM sleep-dependent memory effects, and that are modified to include standardized assessments of REM and NREM dreaming. Learning tasks given before sleep will be retested the next day while the intervening night of sleep is monitored and quantified in the laboratory. Dream ratings of emotional intensity and conceptual content are expected to be associated with overnight improvements in learning, even when correlations between REM/NREM sleep and improvement are statistically removed. Findings will help uncover the functions of dreaming and the mechanisms of memory more generally and may provide insights into strategies for memory improvement.