Abstract：
Although rapid eye movement (REM) sleep is conventionally treated as a unified state, it comprises two distinct microstates: phasic and tonic REM. Recent research emphasizes the importance of understanding the interplay between these microstates, hypothesizing their role in transient shifts between sensory detachment and external awareness. Previous studies primarily employed linear metrics to probe cognitive states, such as oscillatory power, while in this study, we adopt Lempel-Ziv Complexity (LZC), to examine the nonlinear features of electroencephalographic (EEG) data from the REM microstates and to gain complementary insights into neural dynamics during REM sleep. Our findings demonstrate a noteworthy reduction in LZC during phasic REM compared to tonic REM states, signifying diminished EEG complexity in the former. Additionally, we noted a negative correlation between decreased LZC and delta band power, along with a positive correlation with alpha band power. This study highlights the potential of nonlinear EEG metrics, particularly LZC, in elucidating the distinct features of REM microstates. Overall, this research contributes to advancing our understanding of the complex dynamics within REM sleep and opens new avenues for exploring its implications in both clinical and nonclinical contexts.
摘要：
虽然快速眼动（REM）睡眠通常被视为统一状态，它包括两种不同的微观状态：阶段性和强直性REM。最近的研究强调了理解这些微观状态之间相互作用的重要性，假设它们在感觉脱离和外部意识之间的短暂转变中的作用。以前的研究主要采用线性度量来探测认知状态，如振荡功率，而在这项研究中，我们采用Lempel-Ziv复杂性(LZC)，检查来自REM微状态的脑电图（EEG）数据的非线性特征，并获得对REM睡眠期间神经动力学的补充见解。我们的研究结果表明，与强直性REM状态相比，阶段性REM期间LZC的显着降低，表示前者脑电图复杂性降低。此外,我们注意到降低的LZC和delta波段功率之间存在负相关，与α波段功率呈正相关。这项研究强调了非线性脑电指标的潜力，特别是LZC,阐明快速眼动微状态的不同特征。总的来说,这项研究有助于提高我们对REM睡眠中复杂动力学的理解，并为探索其在临床和非临床环境中的意义开辟了新的途径。
