Vyazovskiy Vladyslav V, Tobler Irene
Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstr., 190 CH-8057 Zurich, Switzerland.
Brain Res. 2005 Jul 19;1050(1-2):64-71. doi: 10.1016/j.brainres.2005.05.022.
In humans, EEG power in the theta frequency band (5-8 Hz) during quiet waking increases during sleep deprivation (SD), and predicts the subsequent homeostatic increase of sleep slow-wave activity (SWA; EEG power between 0.5 and 4.0 Hz). These findings indicate that theta power in waking is an EEG variable, which reflects the rise in sleep propensity. In rodents, a number of short sleep attempts, as well as SWA in the waking EEG increase in the course of SD, but neither variable predicts the subsequent homeostatic increase of EEG SWA during recovery sleep. To investigate whether there is an EEG marker for sleep propensity also in rodents, the EEG of the rat was recorded during 6 h SD in the first half of the light period (SDL, n = 7). During SDL, power of the waking EEG showed an increase in the delta (1.5-4 Hz) and low theta (5-6.5 Hz) band. Based on the neck muscle EMG, wakefulness was subdivided into active (high EMG activity) and quiet (low EMG activity) waking. During quiet waking, the theta peak occurred at 5.5 Hz, the frequency at which the increase of EEG power during SD was most pronounced. This increase was due to higher amplitude of theta waves, while wave incidence (frequency) was unchanged. Correlation analysis showed that the rise in EEG power in the 5-7 Hz band during SD predicted the subsequent enhancement of SWA in non-rapid eye movement sleep. The analysis of data of a further batch of rats which were sleep deprived for 6 h after dark onset (SDD, n = 7) revealed a significant increase in theta-wave amplitude during the SD and a tendency for a similar, positive correlation between the increase of theta power (5-7 Hz) and subsequent SWA. The results indicate that in rats, as in humans, a specific waking EEG frequency, i.e., theta power in quiet waking is a marker of sleep propensity.
在人类中，清醒安静状态下θ频段（5 - 8赫兹）的脑电图（EEG）功率在睡眠剥夺（SD）期间会增加，并能预测随后睡眠慢波活动（SWA；0.5至4.0赫兹之间的EEG功率）的稳态增加。这些发现表明，清醒时的θ功率是一种EEG变量，它反映了睡眠倾向的上升。在啮齿动物中，在SD过程中会出现多次短暂的睡眠尝试，以及清醒EEG中的SWA增加，但这两个变量都无法预测随后恢复睡眠期间EEG SWA的稳态增加。为了研究啮齿动物中是否也存在睡眠倾向的EEG标记物，在光照期的前半段对大鼠进行了6小时的SD记录（SDL，n = 7）。在SDL期间，清醒EEG的功率在δ频段（1.5 - 4赫兹）和低θ频段（5 - 6.5赫兹）有所增加。根据颈部肌肉肌电图，清醒状态被细分为活跃（高肌电图活动）和安静（低肌电图活动）清醒。在安静清醒期间，θ峰值出现在5.5赫兹，这是SD期间EEG功率增加最为明显的频率。这种增加是由于θ波的振幅更高，而波的发生率（频率）没有变化。相关分析表明，SD期间5 - 7赫兹频段EEG功率的上升预测了随后非快速眼动睡眠中SWA的增强。对另一批在黑暗开始后被剥夺睡眠6小时的大鼠（SDD，n = 7）的数据分析显示，SD期间θ波振幅显著增加，并且θ功率（5 - 7赫兹）的增加与随后的SWA之间存在类似的正相关趋势。结果表明，在大鼠中，与人类一样，特定的清醒EEG频率，即安静清醒时的θ功率是睡眠倾向的标记物。
