Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany.
Graduate School of Neural and Behavioural Science, International Max Planck Research School, Tübingen, Germany.
Sleep. 2018 Jun 1;41(6). doi: 10.1093/sleep/zsy060.
Mammalian sleep comprises the stages of slow-wave sleep (SWS) and rapid eye movement (REM) sleep. Additionally, a transition state is often discriminated which in rodents is termed intermediate stage (IS). Although these sleep stages are thought of as unitary phenomena affecting the whole brain in a congruent fashion, recent findings have suggested that sleep stages can also appear locally restricted to specific networks and regions. Here, we compared in rats sleep stages and their transitions between neocortex and hippocampus. We simultaneously recorded the electroencephalogram (EEG) from skull electrodes over frontal and parietal cortex and the local field potential (LFP) from the medial prefrontal cortex and dorsal hippocampus. Results indicate a high congruence in the occurrence of sleep and SWS (>96.5%) at the different recording sites. Congruence was lower for REM sleep (>87%) and lowest for IS (<36.5%). Incongruences occurring at sleep stage transitions were most pronounced for REM sleep which in 36.6 per cent of all epochs started earlier in hippocampal LFP recordings than in the other recordings, with an average interval of 17.2 ± 1.1 s between REM onset in the hippocampal LFP and the parietal EEG (p < 0.001). Earlier REM onset in the hippocampus was paralleled by a decrease in muscle tone, another hallmark of REM sleep. These findings indicate a region-specific regulation of REM sleep which has clear implications not only for our understanding of the organization of sleep, but possibly also for the functions, e.g. in memory formation, that have been associated with REM sleep.
哺乳动物的睡眠包括慢波睡眠 (SWS) 和快速眼动 (REM) 睡眠阶段。此外，通常还会区分出一个过渡状态，在啮齿动物中称为中间状态 (IS)。尽管这些睡眠阶段被认为是影响整个大脑的单一现象，但最近的研究结果表明，睡眠阶段也可能局部限制在特定的网络和区域。在这里，我们比较了大鼠的睡眠阶段及其在大脑新皮层和海马体之间的转换。我们同时记录了颅骨电极上的脑电图 (EEG)，来自前额叶和顶叶皮层，以及内侧前额叶皮层和背侧海马体的局部场电位 (LFP)。结果表明，不同记录部位的睡眠和 SWS 的发生具有高度一致性 (>96.5%)。REM 睡眠的一致性较低 (>87%)，IS 最低 (<36.5%)。在睡眠阶段转换时出现的不一致性在 REM 睡眠中最为明显，在所有时期的 36.6%中，海马体 LFP 中的 REM 睡眠比其他记录更早开始，平均间隔为 17.2 ± 1.1 s 在海马体 LFP 和顶叶 EEG 中的 REM 起始之间（p < 0.001）。海马体中 REM 睡眠的早期开始伴随着肌肉张力的降低，这是 REM 睡眠的另一个标志。这些发现表明 REM 睡眠受到区域特异性调节，这不仅对我们理解睡眠的组织有明确的影响，而且可能对与 REM 睡眠相关的功能，例如记忆形成，也有影响。
