College of Education, Psychology and Social Work, Flinders University, Adelaide, SA, Australia.
College of Medicine and Public Health, Adelaide Institute for Sleep Health: A Flinders Centre of Research Excellence, Flinders University, Adelaide, SA, Australia.
J Sleep Res. 2021 Aug;30(4):e13232. doi: 10.1111/jsr.13232. Epub 2020 Nov 17.
Behavioural responses to auditory stimuli cease in late N1 or early N2 sleep. Yet, responsiveness to minimal intensity tactile stimuli and the correspondence with sleep microstructure during the sleep onset period is unknown. The aim of the present study was to investigate sleep microstructure using quantitative electroencephalography analysis when participants behaviourally responded to minimal intensity vibratory stimuli compared to when participants did not respond to stimuli during the sleep onset period. Eighteen participants wore a device that emitted vibratory stimuli to which individuals responded by tapping their index finger. A fast Fourier transform using multitaper-based estimation was applied to electroencephalography signals in 5-s epochs. Participants exhibited increases in higher frequencies 5 s before and immediately after the stimulus presentation when they responded to the stimulus compared to when they did not respond during all sleep stages. They also had greater delta power after stimulus onset when they did not respond to stimuli presented in N1 and N2 sleep compared to when they did respond. Participants responded to a significantly greater proportion of stimuli in wake than in N1 sleep (p < .001, d = 2.38), which was also significantly greater than the proportion of responses in N2 sleep (p < .001, d = 1.12). Participants showed wake-like sleep microstructure when they responded to vibratory stimuli and sleep-like microstructure when they did not respond during all sleep stages. The present study adds to the body of evidence characterising N1 sleep as a transitional period between sleep and wake containing rapid fluctuations between these two states.
行为反应在晚 N1 期或早 N2 期睡眠中停止。然而，在睡眠起始期，对最小强度触觉刺激的反应性以及与睡眠微结构的对应关系尚不清楚。本研究的目的是在参与者对最小强度振动刺激做出行为反应时，与参与者在睡眠起始期对刺激不做出反应时相比，使用定量脑电图分析来研究睡眠微结构。18 名参与者佩戴了一个发出振动刺激的设备，个体通过敲击食指来对刺激做出反应。使用基于多谱估计的快速傅里叶变换对 5 秒段的脑电图信号进行分析。与不响应刺激时相比，参与者在响应刺激时，在刺激呈现前 5 秒和刺激呈现后立即表现出更高频率的增加，在所有睡眠阶段均如此。与响应刺激时相比，当他们在 N1 和 N2 睡眠中不响应刺激时，其刺激后 delta 功率更大。与 N1 睡眠相比，参与者在清醒时对刺激的响应比例显著更高（p<.001，d=2.38），与 N2 睡眠时的响应比例也显著更高（p<.001，d=1.12）。参与者在对振动刺激做出反应时表现出类似于清醒的睡眠微结构，而在所有睡眠阶段不响应刺激时表现出类似于睡眠的微结构。本研究增加了将 N1 睡眠描述为睡眠和清醒之间的过渡阶段的证据，该阶段包含这两种状态之间的快速波动。
