Institute of Psychology, Eötvös Loránd University, Budapest, Hungary.
Nyírő Gyula Hospital, National Institute of Psychiatry and Addictions, Budapest, Hungary.
Sleep. 2018 Mar 1;41(3). doi: 10.1093/sleep/zsx210.
Rapid eye movement (REM) sleep is characterized by the alternation of two markedly different microstates, phasic and tonic REM. These periods differ in awakening and arousal thresholds, sensory processing, and spontaneous cortical oscillations. Previous studies indicate that although in phasic REM, cortical activity is independent of the external environment, attentional functions and sensory processing are partially maintained during tonic periods. Large-scale synchronization of oscillatory activity, especially in the α- and β-frequency ranges, can accurately distinguish different states of vigilance and cognitive processes of enhanced alertness and attention. Therefore, we examined long-range inter- and intrahemispheric as well as short-range electroencephalographic synchronization during phasic and tonic REM periods quantified by the weighted phase lag index. Based on the nocturnal polysomnographic data of 19 healthy adult participants, we showed that long-range inter- and intrahemispheric α and β synchrony was enhanced in tonic REM states in contrast to phasic ones, and resembled α and β synchronization of resting wakefulness. On the other hand, short-range synchronization within the γ-frequency range was higher in phasic compared with tonic periods. Increased short-range synchrony might reflect local and inwardly driven sensorimotor activity during phasic REM periods, whereas enhanced long-range synchrony might index frontoparietal activity that reinstates environmental alertness after phasic REM periods.
快速眼动 (REM) 睡眠的特点是两种明显不同的微状态交替出现，即相位性 REM 和紧张性 REM。这些时期在唤醒和觉醒阈值、感觉处理和自发皮质振荡方面存在差异。先前的研究表明，尽管在相位性 REM 期间，皮质活动与外部环境无关，但在紧张期期间，注意力功能和感觉处理部分得到维持。振荡活动的大规模同步，特别是在 α 和 β 频带范围内，可以准确地区分不同的警觉状态和增强警觉和注意力的认知过程。因此，我们通过加权相位滞后指数检查了相位性 REM 和紧张性 REM 期间的长程、半球间和半球内以及短程脑电图同步。基于 19 名健康成年参与者的夜间多导睡眠图数据，我们表明，与相位性 REM 相比，在紧张性 REM 状态下，长程半球间和半球内的 α 和 β 同步性增强，类似于静息清醒时的 α 和 β 同步性。另一方面，与紧张期相比，γ 频带范围内的短程同步性更高。短程同步性增加可能反映了相位性 REM 期间局部和内向驱动的感觉运动活动，而长程同步性增强可能反映了前顶叶活动，该活动在相位性 REM 后恢复环境警觉性。
