Laboratory of Sleep/Wake Neurobiology, Institute of Higher Nervous Activity and Neurophysiology of the Russian Academy of Sciences, Moscow, Russia.
Department of Normal Physiology, Medical Institute of the Peoples' Friendship University of Russia, Moscow, Russia.
J Neurophysiol. 2021 Dec 1;126(6):1991-2000. doi: 10.1152/jn.00364.2021. Epub 2021 Nov 24.
The conventional staging classification reduces all patterns of sleep polysomnogram signals to a small number of yes-or-no variables labeled wake or a stage of sleep (e.g., W, N1, N2, N3, and R for wake, the first, second, and third stages of non-rapid eye movement sleep and rapid eye movement sleep, respectively). However, the neurobiological underpinnings of such stages remained to be elucidated. We tried to evaluate their link to scores on the first and second principal components of the EEG spectrum (1PCS and 2PCS), the markers of two major groups of promoters/inhibitors of sleep/wakefulness delineated as the drives for sleep and wake, respectively. On two occasions, polysomnographic records were obtained from 69 university students during 50-min afternoon naps and 30-s stage epochs were assigned to 1PCS and 2PCS. Results suggested two dimensionality of the structure of individual differences in amounts of stages. Amount of N1 loaded exclusively on one of two dimensions associated with 1PCS, amounts of W and N2 loaded exclusively on another dimension associated with 2PCS, and amount of N3 was equally loaded on both dimensions. Scores demonstrated stability within each stage, but a drastic change in just one of two scores occurred during transitions from one stage to another on the way from wakefulness to deeper sleep (e.g., 2PCS changed from >0 to <0 during transition W→N1, 1PCS changed from <0 to >0 during transition N1→N2). Therefore, the transitions between stages observed during short naps might be linked to rapid changes in the reciprocal interactions between the promoters/inhibitors of sleep/wakefulness. In the present nap study, two dimensionality of the structure of individual differences in sleep stages was revealed. These results also suggested that individual variation in the sleep and wake drives associated with the first and second principal components of the EEG spectrum might underlie this structure. It seemed that each stage might be related to a certain, stage-specific combination of wake-sleep promoting/inhibiting influences associated with these drives for sleep and wake.
传统的分期分类将所有睡眠多导睡眠图信号模式简化为少数几个是或否的变量，分别标记为清醒或睡眠阶段（例如，W、N1、N2、N3 和 R 分别代表清醒、非快速眼动睡眠的第一、第二和第三阶段以及快速眼动睡眠）。然而，这些阶段的神经生物学基础仍有待阐明。我们试图评估它们与脑电图频谱第一和第二主成分（1PCS 和 2PCS）得分之间的关系，这两个主成分分别标记为睡眠/觉醒的两个主要促进/抑制因子群的标志物，分别为睡眠和觉醒的驱动力。在两次情况下，从 69 名大学生中获得了 50 分钟下午小睡的多导睡眠图记录，并且将 30 秒的阶段时段分配给 1PCS 和 2PCS。结果表明，个体差异在阶段数量上存在二维结构。N1 的量仅加载到与 1PCS 相关的两个维度之一上，W 和 N2 的量仅加载到与 2PCS 相关的另一个维度上，而 N3 的量则均匀加载到两个维度上。得分在每个阶段内具有稳定性，但是在从清醒到更深睡眠的过程中，从一个阶段到另一个阶段的过渡中，两个得分中的一个发生了急剧变化（例如，2PCS 在从 W 到 N1 的过渡中从>0 变为<0，1PCS 在从 N1 到 N2 的过渡中从<0 变为>0）。因此，在短时间小睡期间观察到的阶段之间的转换可能与睡眠/觉醒促进/抑制因子之间的相互作用的快速变化有关。在本小睡研究中，揭示了睡眠阶段个体差异结构的二维性。这些结果还表明，与脑电图频谱的第一和第二主成分相关的睡眠和觉醒驱动力的个体差异可能构成了这种结构。似乎每个阶段都可能与与这些睡眠和觉醒驱动力相关的特定、特定阶段的促进/抑制影响组合有关。
