Neurobehavioural and physiological consequences of sleep deprivation in humans

睡眠的功能在很大程度上仍然是一个谜。研究睡眠功能的一种方法是检查不同睡眠时间对特定大脑过程的影响。我的实验室一直专注于睡眠在认知过程和情绪调节中的作用。大量研究表明，睡眠不足会损害警觉性、注意力、记忆力和情绪，但这些损害的神经基础仍然知之甚少。虽然人们早就知道主观情绪抱怨是睡眠不佳的结果，但研究人员直到最近才开始研究睡眠在情绪调节中的作用，包括大脑如何处理图片和面部表情中的情绪信息，以及睡眠不足如何导致攻击性行为。我们最近的研究表明，一晚睡眠不足(大约33小时清醒)会导致与威胁相关的愤怒和恐惧面部表情的行为和神经反应，但对悲伤的面部表情反应迟钝。这种对情绪表达的不同处理告诉我们，睡眠不足会影响认知过程的性质，这对许多睡眠剥夺群体具有重要意义。我们还首次报告称，一夜失眠与男性睾丸素水平的大幅下降以及实验室任务中攻击性行为的相关减少有关。在下一个资助期提出的这项研究将以多种方式扩展这些新的发现，并寻求研究睡眠在情绪调节中的作用的新方法。首先，我们将研究一种不那么极端的睡眠干扰水平，通过检查每晚被限制在3、4或5小时的睡眠，在一个或多个晚上；这是一种常见的睡眠损失水平，会导致警觉性和注意力的累积缺陷。我们将通过检测大脑对不同情绪效价(从中性到积极和消极)的面孔、图片和音频和视频片段的反应，进一步研究睡眠在处理情绪信息中的作用。此外，我们将通过使用两种不同的攻击性验证任务来研究男性和女性(同时控制激素的使用和月经周期的不同阶段)，再次研究睡眠和激素在攻击性行为中的作用。我们将通过测量静息心率来进一步探索与睡眠相关的情绪处理和攻击行为变化的本质，因为它被认为是个人对情感信息做出反应的能力的标志。最后，由于快速眼动睡眠(通常与做梦相关的睡眠阶段)被认为在情绪调节中起作用，我们将研究选择性快速眼动睡眠剥夺对情绪处理和记忆的影响。具体地说，我们将探索快速眼动睡眠是否在巩固情绪材料以及减轻情绪刺激的“刺痛”的适应功能方面发挥作用。检查与睡眠不足导致的感知和行为改变相关的生理活动将帮助我们理解睡眠不足如何以及为什么会影响清醒的功能。这些研究将增进我们对睡眠在唤醒认知功能和情绪调节中的基本功能作用的了解。这项研究的结果将对理解许多睡眠剥夺群体中的人类行为产生影响，特别是对于那些睡眠中断和情感成分在发挥作用的人，如儿童和青少年，以及法医和精神病学人群。

The functions of sleep remain largely a mystery. One way to investigate the functions of sleep is by examining the effects of varying amounts of sleep on specific brain processes. My lab has focused on the role of sleep in cognitive processing and emotion regulation. A large body of research has shown that sleep loss impairs alertness, attention, memory, and mood, but the neural basis of these impairments remains poorly understood. While subjective mood complaints have long been known to be a consequence of poor sleep, researchers have only recently begun to investigate the role of sleep in emotion regulation, including how the brain processes emotional information in pictures and facial expressions, and how sleep loss contributes to aggressive behaviour. Our recent work showed that one night of sleep deprivation (about 33 hours awake) led to behavioural and neural reactivity for threat-related Angry and Fearful facial expressions, yet a blunted response to Sad facial expressions. This differential processing for emotional expressions informs us about the nature of cognitive processes that are affected by sleep loss, and has significant implications for many sleep deprived groups. We were also the first to report that one night of sleep loss was associated with a substantial decrease in testosterone levels in men and an associated reduction in aggressive behaviour on a laboratory task. The research proposed in the next grant period will expand on these novel findings in a number of ways, as well as pursue new approaches to studying the role of sleep in emotion regulation. First, we will study a less extreme level of sleep disruption by examining sleep that is restricted to 3, 4, or 5 hours per night, over one or more nights; this is a level of sleep loss that is commonly experienced and leads to cumulative deficits in alertness and attention. We will further investigate the role of sleep in processing emotional information by examining brain responses to faces, pictures, and audio and video clips that vary in emotional valance (from neutral to positive and negative). In addition, we will again investigate the role of sleep and hormones in aggressive behaviour, by studying both men and women (while controlling for hormone use and phases of the menstrual cycle) using two different validated tasks of aggression. We will further explore the nature of the sleep-related change in emotion processing and aggressive behaviour by measuring resting heart rate because it is considered a marker of individuals’ ability to respond to affective information. Lastly, since REM sleep (the sleep stage commonly associated with dreaming) has been proposed to play a functional role in emotion regulation, we will examine the effects of selective REM sleep deprivation on emotion processing and memory. Specifically, we will explore whether REM sleep plays a role in both consolidation of emotional material as well as an adaptive function to lessen the “sting” of emotional stimuli. Examining physiological activity that is associated with altered perception and behaviour as a result of sleep loss will help us to understand how and why sleep loss impacts waking function. These studies will advance our knowledge of the basic functional role of sleep in waking cognitive function and emotion regulation. The outcomes of this research will have implications for understanding human behaviour in many sleep deprived groups, especially for those with a sleep disruption and affective component at play, such as children and adolescents, and forensic and psychiatric populations.