Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford Molecular Pathology Institute, Dunn School of Pathology, South Parks Road, Oxford, OX13RE, United Kingdom.
Department of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, Oxford, OX1 3PT, United Kingdom.
Sci Rep. 2018 Oct 26;8(1):15343. doi: 10.1038/s41598-018-33480-1.
Circadian rhythms and sleep-wake history determine sleep duration and intensity, and influence subsequent waking. Previous studies have shown that T cycles - light-dark (LD) cycles differing from 24 h - lead to acute changes in the daily amount and distribution of waking and sleep. However, little is known about the long-term effects of T cycles. Here we performed continuous 10 day recording of electroencephalography (EEG), locomotor activity and core body temperature in C57BL/6 mice under a T20 cycle, to investigate spontaneous sleep and waking at baseline compared with when the circadian clock was misaligned and then re-aligned with respect to the external LD cycle. We found that the rhythmic distribution of sleep was abolished during misalignment, while the time course of EEG slow wave activity (1-4 Hz) was inverted compared to baseline. Although the typical light-dark distribution of NREM sleep was re-instated when animals were re-aligned, slow wave activity during NREM sleep showed an atypical increase in the dark phase, suggesting a long-term effect of T cycles on sleep intensity. Our data show that circadian misalignment results in previously uncharacterised long-term effects on sleep, which may have important consequences for behaviour.
昼夜节律和睡眠-觉醒史决定了睡眠时间和强度，并影响随后的觉醒。先前的研究表明，与 24 小时不同的明暗（LD）周期 T 周期会导致清醒和睡眠的日常量和分布发生急性变化。然而，对于 T 周期的长期影响知之甚少。在这里，我们在 T20 周期下对 C57BL/6 小鼠进行了连续 10 天的脑电图（EEG）、运动活动和核心体温记录，以研究与外部 LD 周期失相后基线相比自发睡眠和觉醒的情况，然后重新与外部 LD 周期对齐。我们发现，在失相期间，睡眠的节律分布被消除，而 EEG 慢波活动（1-4 Hz）的时程与基线相比发生了反转。尽管当动物重新对齐时重新建立了 NREM 睡眠的典型明暗分布，但 NREM 睡眠期间的慢波活动在暗相中表现出异常增加，表明 T 周期对睡眠强度有长期影响。我们的数据表明，昼夜节律失相导致睡眠出现以前未表征的长期影响，这可能对行为有重要影响。
