睡眠剥夺对大脑状态影响的时-频-空分析

结合脑电信号EEG的小波变换和非负矩阵分解，寻求正常睡眠和睡眠剥夺（sleep deprivation，SD）两种条件下，大脑状态在时域、频域和空域的主要差异，探讨其发生机制，并建立综合评价方法．为此，获取两种条件下11名受试者的听觉诱发电位，对脑电gamma频段做小波变换得到时频信息，采用ANOVA统计计算每个时频点的F检验值，对此进行两分量的非负矩阵分解结果表明，SD引起的大脑状态变化主要发生在40Hz左右，刺激后约400ms处的额叶和前额叶位置．基于此，分别从时频复合域、时域和空域的角度来分析具体的变化，发现SD引起gamma振荡减少，活动时间延迟，额叶功能区兴奋性降低，推断SD的作用机制在于降低了神经元的活动和同步化效应．分析表明结合EEG的小波变换和非负矩阵分解，可以建立一条从时、频、空三域全面评价大脑状态主要变化的途径．

Evaluation of the Effects of Sleep Deprivation on Brain State Based on Time-Frequency-Space Decomposition of EEG

Non-negative matrix factorization （NMF） was applied to wavelet transformed EEG to find the major difference of brain state between normal and one night＇s sleep deprived conditions in time, frequency and space domains, and an integrated way was built to evaluate the effect of sleep deprivation （ SD ）. Auditory evoked potentials of eleven healthy volunteers were recorded under two conditions and were wavelet transformed to time-frequency （TF） values in EEG gamma frequency range. The F-test statistic of TF values by ANOVA were decomposed into two components by NME Results show that after SD, the major difference appears at about 400 ms after stimuli around 40 Hz on prefrontal and frontal lobes. Comparing detailed information in time-frequency, time and space domains, we find that the gamma oscillation of auditory response decreases and delays, activity of frontal lobes weakens after SD, which indicates that SD brings negative effect on neuronal activity and synchrony. Combining wavelet transform with NMF, analysis of EEG can be an integrated way to evaluate the change of brain states in three domains.