Strategically strengthening declarative memories during sleep

准确记忆信息的能力是人类成功的关键。然而，由于每天都有新的信息加入，人类大脑不断扩大的记忆库需要不断地重组。如何才能最大限度地利用大量涌入的新信息？在美国国家科学基金会的资助下，西北大学的肯·帕勒博士正在研究一个有趣的假设，即睡眠期间的大脑活动有助于有效的记忆储存。虽然有些记忆会迅速消失，但有些记忆会持续数年，这可能是因为大脑网络发生了一系列变化。目前还不清楚记忆是如何在人脑中持久储存的，以及睡眠在多大程度上可能有所帮助。这个项目探索了一种改进记忆存储的新方法。当一个人睡觉时，与之前所学到的信息相关的特定声音会轻轻地呈现出来。从理论上讲，这些声音可以在睡眠中促进记忆排练，从而在醒来后短时间内改善记忆。因此，这个过程提供了一个观察睡眠的潜在好处的机会——加强记忆，这可能是持久记忆储存的基础。这个项目探索了这些“睡眠声音”有效的过程，包括(a)确定睡眠声音是否能产生持久的记忆改善，(b)比较空间位置、单词和特定手动动作的学习，以及(c)显示睡眠的哪些阶段适合这种记忆加强。实验还比较了参与者在醒着和睡着时可能增强的记忆。该项目包括对大脑活动的脑电图测量，以进一步阐明睡眠期间记忆改善的大脑机制。虽然人们普遍认为在睡眠中不能学习新的信息，但在睡觉前学习的信息显然可以在睡眠中排练。这个项目提供了新的证据，证明了一段时间的睡眠如何能改善记忆力，以及这种改善如何能集中在特定的信息上。通过该项目获得的结果为理解一般的记忆存储，特别是睡眠期间的记忆处理提供了新的杠杆。这个项目正在扩大人们对睡眠在稳定记忆和形成这些记忆之间的相互联系方面所起的特殊作用的认识，这些记忆可以成为创造性思维的基础。通过加深对睡眠中记忆如何加强的理解，最终将产生在课堂上促进最佳教育成果，增强新信息和技能的日常获取，以及在法律环境中评估记忆等应用的影响。重视睡眠和学习也将有助于强调适当睡眠量对公众健康的重要性。

The ability to accurately remember information is central to human success. Yet, as new information is added every day, the human brain's expanding storehouse of memories requires continual restructuring. How can the massive influx of new information be used to best advantage? With funding from the National Science Foundation, Ken Paller, Ph.D., of Northwestern University is investigating the intriguing hypothesis that brain events during sleep are instrumental for effective memory storage. Although some memories rapidly fade away, others endure for years, presumably because of a progression of changes in brain networks. It remains unclear how memories are enduringly stored in the human brain, and to what extent sleep might be helpful. This project explores a novel way in which memory storage can be improved. Specific sounds related to information learned previously are presented softly while an individual sleeps. These sounds can in theory prompt memory rehearsal during sleep, leading to an improvement in memory tested a short time after awakening. The procedures thus provide an opportunity to observe a potential benefit of sleep -- memory strengthening that could underlie lasting memory storage. This project explores the procedures whereby these "sleep-sounds" are effective, including (a) determining whether long-lasting memory improvement can be produced by sleep-sounds, (b) comparing learning of spatial locations, of words, and of specific manual actions, and (c) showing which stages of sleep are amenable to this memory strengthening. Experiments also compare the memory strengthening that is possible when participants are awake versus asleep. Electroencephalographic measures of brain activity are included in the project to further elucidate the brain mechanisms of memory improvement during sleep. Although it is widely thought that new information cannot be learned during sleep, information learned before going to sleep can apparently be rehearsed during sleep. This project provides new evidence about how a period of sleep can lead to memory improvement and how that improvement can be focused on specific information.Results obtained through this project provide new leverage on understanding memory storage in general, and memory processing during sleep in particular. This project is expanding knowledge about the special role that sleep can play in the stabilization of memories and in the formation of interconnections among these memories that can be the basis for creative thinking. By advancing understanding of how memories are strengthened during sleep, implications will ultimately arise for promoting optimal educational outcomes in the classroom, enhancing the daily acquisition of new information and skills, and evaluating memory in legal contexts, among other applications. An appreciation of sleep and learning will also aid efforts to emphasize the importance of suitable amounts of sleep for public health.