Neurocognitive Dynamics Of Sleep Onset

在国家科学基金会的支持下，沃克博士将对人类大脑系统进行为期一年的研究，该系统控制着从完全意识到睡眠状态的减少意识的下降，并产生睡眠开始做梦的认知体验。睡眠是人类生活中必不可少的一部分，大约占据了我们三分之一的时间。从清醒到睡眠的转变可以说是人类大脑和思维通常经历的最显著的转变。尽管我们开始了解是什么大脑机制触发了这种转变，但产生睡眠状态的实际过程仍然未知。另外令人感兴趣的是伴随这种清醒-睡眠转换的精神体验类型，通常包括短暂的幻觉/梦境，其中包含视觉和听觉事件以及运动的感觉。最近的研究表明，这些睡眠开始的梦与白天新奇经历的记忆回放和巩固有关，特别是那些需要学习新技能的经历（例如，长时间从事新奇的身体或精神活动，如第一天滑雪）。沃克博士和他的同事们通过让人类受试者在白天长时间玩滑雪模拟游戏，已经能够可靠地产生几乎相同的、刻板的睡眠开始的梦。本项目使用这种方法来观察和控制志愿者在睡眠开始时做梦的认知过程，同时用功能性磁共振扫描仪对志愿者的大脑进行成像。确定参与睡眠开始过程的大脑机制将为基础神经科学和临床研究提供具有广泛价值的信息。它不仅会增加我们对睡眠大脑和做梦大脑的神经认知基础的理解，而且还会扩大我们对人类感官和知觉经验的理解，以及对新知识和技能如何获得、学习和再加工的理解。这些信息还将为人类感知、认知和学习的新理论提供一个平台，并将有助于制定各种神经和睡眠障碍的新治疗方法。

With National Science Foundation support, Dr. Walker will conduct a year long investigation of the human brain systems which control the descent from full consciousness into the reduced consciousness of sleep and produce the cognitive experience of sleep onset dreaming. Sleep is an essential part of human life, occupying approximately one third of our time. The shift from wake to sleep arguably represents the most striking transition that the human brain and mind normally experiences. Although we are beginning to understand what brain mechanisms trigger this shift, the actual processes that produce the state of sleep remain unknown. Of additional interest is the type of mental experience that accompanies this wake-sleep transition, often involving brief hallucinations/dreams containing visual and auditory events as well as feelings of movement. Recent studies have suggested that these sleep-onset dreams are related to the re-play and consolidation of memories of novel daytime experiences, particularly those requiring the learning of new skills (e.g. engage in novel physical or mental activities for extended periods of time such as the first day of skiing). Dr. Walker and colleagues have been able to reliably produce near identical, stereotyped sleep-onset dreams by having human subjects play a ski simulator game for extended periods during the day. The present project uses this method to observe and control the cognitive processes of sleep onset dreaming as volunteers brains are being imaged in functional magnetic resonance scanner.Identifying the brain mechanisms involved in the sleep-onset process would provide information of wide value to both the basic neurosciences and to clinical research. It would not only increase our understanding of the neurocognitive basis of both the sleeping brain and the dreaming mind, but would also expand our understanding of human sensory and perceptual experience and of how new knowledge and skills are acquired, learned and reprocessed. This information would also provide a platform for new theories of human perception, cognition and learning, and will assist in the formulation of new treatments for a variety of neurological and sleep disorders.