A phenomena of resonance of MEG and EEG signal in sensory cortexes

我们测量了脑磁图上的听觉稳态反应（ASSRs），以正弦振幅调制的音调叠加不同强度的持续白噪声。研究了ASSR的功率和相位相干性，发现与无噪声时相比，有一定噪声时ASSR与刺激的同步性增加，ASSR的功率增加，表明随机共振（SR）。我们还测量了单独噪声的听力阈值，发现SR的最佳噪声强度略大于大多数受试者的阈值。由于功率和相干曲线随噪声与信号比的变化在受试者之间差异很大，因此我们使用功率和相位相干的最大值作为测试统计量来测试群体数据。

We measured auditory steady state responses(ASSRs) in magneto-encephalogram to the sinusoidal amplitude modulated tone superimposed with ongoing white noise of various intensities. The power and phase coherence of the ASSR were investigated and stochastic resonance(SR) was indicated by increased synchrony to the stimulus and by increase in power of the ASSR when there was certain amount of noise compared with those measured without the noise. We also measured the hearing threshold for the noise alone and found that the optimum noise intensity for SR was slightly larger than the threshold for most of the subjects. As the power and coherence curves plotted against the noise to signal ratio varied considerably among subjects, we used the maximum values of power and phase coherence as test statistics for testing the group data.