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脑电相干幅谱是目前用来研究脑电同步性变化的主要指标 ,但由于计算中可靠性的要求 ,不可能同时具备较高的时间和频率分辨率 ,因此其应用价值受限 ,特别是难以进行事件关联性观察。为此 ,本文报道一个可以克服上述局限的新方法。方法 1 .利用快速哈特莱变换和建立的算法得出具有 1s和 1Hz分辨率的相干相位。 2 .对相干相位值序列的动态变化和分布特征进行分析。 3.根据相干相位的分布特征提出了脑电同步指数谱SynI(f)的概念和计算方法。利用此方法 ,计算了 2 5名正常青年被试者在对视觉信号进行选择区分反应作业中的事件关联脑电同步指数谱。结果 ( 1 )左右脑区之间的脑电同步指数谱表现出一定的脑区 -频率特征 ,在额区α活动的SynI高于其它频率 ,但在后脑区则相反 ;( 2 )除中央脑区外 ,额区和后脑区的中线与左右两侧的SynI有不大但统计上显著的差别 ,且都是右侧大于左侧 ;( 3)与VC比 ,DR作业中靶信号在中央脑区和后脑区引起SynI显著增大 ,但在中央脑区主要发生在 7～ 2 3Hz,而在后脑区则在 1～ 4Hz,额区无明显变化 ;对非靶信号的反应在程度上明显小于靶信号 ,特别是后脑区的 1～ 4Hz活动。结论本文报道的脑电同步指数谱可以从一个新的侧面揭示出脑在进行认知活动中的空间 -频率反应特性。
EEG is currently used to study changes in the main indicators of EEG synchronization, but due to the calculation of the reliability requirements, it is impossible to have both high time and frequency resolution, so its value is limited, in particular It is difficult to observe the events. To this end, this article reports a new method that can overcome the above limitations. Method 1. Coherent phases with resolutions of 1s and 1Hz are derived using the fast Hadley transformation and the established algorithm. Analyze the dynamic change and distribution of coherent phase sequence. According to the distribution of coherence phase, the concept and calculation method of SynI (f) is proposed. Using this method, twenty five normal subjects were enrolled in the event-related EEG profile of selective reaction to visual signals. Results (1) The EEG spectrum between the left and right brain regions showed some brain-frequency characteristics. Syn I activity in the frontal area was higher than other frequencies but opposite in the posterior brain region. (2) Outside the area, SynI of the midline and left and right sides of the frontal and the hindbrain regions were not statistically significant but statistically greater than the left ones. (3) Compared with the VC, Syn I increased significantly in the brain and cerebellum, but mainly in the central brain region between 7 and 23 Hz and in the posterior brain region between 1 and 4 Hz, with no significant changes in the frontal area; the response to non-target signals was significantly less Target signals, especially 1 ~ 4Hz activity in the posterior brain area. Conclusion The EEG profile reported in this paper can reveal the spatial-frequency response of brain during cognitive activity from a new perspective.