睡眠剥夺对脑电活动相位相干性的影响研究

STUDY ON THE EFFECT OF SLEEP DEPRIVATION ON PHASE COHERENCE OF EEG ACTIVITY

将小波变换和相位相干分析应用到事件相关电位实验的脑电信号中。在正常状态和一夜睡眠剥夺状态下提取12名受试者的视觉ERP,进行30-60Hz的小波变换,以此计算前额叶区域的导联内相位相干,以及枕叶和前额叶之间的相位相干性。发现睡眠剥夺引起前额叶的导联内相位相干活动减少和延迟,表明大脑维持完成任务的能力下降;枕叶与前额叶之间的gamma波段相位相干活动减少,表明功能区域之间的电活动传递效应减弱。基于小波变换的相位相干分析可以得到脑电的同步活动,为更好地理解睡眠的机制和评价睡眠剥夺对认知的影响提供了一条思路。

Phase coherence analysis is applied on wavelet transformed EEG. Visual evoked potentials of twelve healthy volunteers were recorded under two conditions including normal state and one night＇s sleep deprived state, and were wavelet transformed to time-frequency values between 30 to 60 Hz. The inter-trial phase coherence （ITPC） of prefrontal lobe and the evoked response phase coherence （ERPCOH） between prefrontal lobe and occipital lobes were calculated. Results showed that after sleep deprivation, activities of ITPC decreased and delayed on prefrontal lobe, indicating the ability of brain for maintaining its state to respond to repeated stimulus was decreased; activities of ERPCOH between prefrontal and occipital lobes reduced after sleep deprivation, indicating information transfer between functional areas was lessened. Based on wavelet transform, analysis of phase coherence can provide a way to evaluate the effect of sleep deprivation on brain cognition and to help to understand the working mechanism of sleep.