Ma Ning, Ning Qian, Li Mingzhu, Hao Chao
Philosophy and Social Science Laboratory of Reading and Development in Children and Adolescents (South China Normal University), Ministry of Education, Guangzhou 510631, China.
Center for Sleep Research, Center for Studies of Psychological Application, Guangdong Key Laboratory of Mental Health & Cognitive Science, School of Psychology, South China Normal University, Guangzhou 510631, China.
Brain Sci. 2023 Apr 16;13(4):667. doi: 10.3390/brainsci13040667.
A series of studies have suggested that stage N2 is vulnerable and strongly affected by the first-night effect (FNE). However, the neurophysiological mechanism underlying the vulnerability of stage N2 of the FNE has not been well examined. A total of 17 healthy adults (11 women and 6 men, mean age: 21.59 ± 2.12) underwent two nights of polysomnogram recordings in the sleep laboratory. We analyzed sleep structure and central and autonomic nervous system activity during stage N2 and applied the electroencephalographic (EEG) activation index (beta/delta power ratio) and heart rate variability to reflect changes in central and autonomic nervous system activity caused by the FNE. Correlation analyses were performed between EEG activation and heart rate variability. The results showed that EEG activation and high-frequency heart rate variability increased on the adaptation night (Night 1). Importantly, EEG activation was significantly associated with the percentage of stage N1, and the correlation between EEG activation and high-frequency heart rate variability decreased due to the FNE. These findings indicate that the FNE affects the instability of stage N2 by increasing central nervous system activity and uncoupling the activity between the central and autonomic nervous systems.
一系列研究表明，N2期睡眠较为脆弱，且受到首夜效应（FNE）的强烈影响。然而，FNE的N2期睡眠脆弱性背后的神经生理机制尚未得到充分研究。共有17名健康成年人（11名女性和6名男性，平均年龄：21.59±2.12）在睡眠实验室进行了两晚的多导睡眠图记录。我们分析了N2期睡眠期间的睡眠结构以及中枢和自主神经系统活动，并应用脑电图（EEG）激活指数（β/δ功率比）和心率变异性来反映FNE引起的中枢和自主神经系统活动变化。对EEG激活与心率变异性进行了相关性分析。结果显示，适应夜（第1晚）的EEG激活和高频心率变异性增加。重要的是，EEG激活与N1期睡眠的百分比显著相关，并且由于FNE，EEG激活与高频心率变异性之间的相关性降低。这些发现表明，FNE通过增加中枢神经系统活动以及使中枢和自主神经系统之间的活动解耦，从而影响N2期睡眠的不稳定性。
