【摘要】 为进一步阐明事件关联电位（ＥＲＰｓ）中Ｐ３００成分的心理意义，在２２名健康青年男性被试者中，研究了靶与非靶二种视觉刺激概率均为０．５的条件下，对随机刺激序列和规则刺激序列的选择反应Ｐ３００成分的基本时空模式及其头皮分布特点。结果为：选择反应中靶与非靶刺激均诱发了明显的Ｐ３００，对信号的判断以及决策是其最基本的心理因素；在顶区靶Ｐ３００幅度大于非靶，且其潜伏期最短，而在额区非靶Ｐ３００幅度则大于靶Ｐ３００，且潜伏期在此区最短，这种特点表明顶区和额区在信号处理中功能作用不同；刺激序列结构规则化使Ｐ３００幅度降低，而对其潜伏期影响不大。更多还原

【Abstract】 The true features and scalp distribution of P300 in selective response to two visual signals(green flash as target and red flash as non target) with half to half probabilities in random or regular sequence were studied in 22 healthy young men. During selective response test the subjects were asked to make a switch response to green flash and ignore the red. The main results were as follows:both target and non target stimuli elicited significant P300, which are based on discrimination and decision making;both target and non target P300 were centrally dominant. But target P300 amplitude was higher than that of non target P300 and had shortest latency at parietal scalp, while the amplitude of non target P300 was higher than that of target P300 and had shortest latency at frontal scalp,this shows that parietal and frontal structures of the brian play different roles in signal proccessing.The features and scalp distribution of P300 of selective response to random and regular sequences of visual stimuli were similar, but the P300 amplitude to stimuli in regular sequence were lower than that in random sequence. The results indicated that the most fundamental factor inducing P300 is the discrimination or decision mental process; the distribution of P300’s amplitude and latency on the scalp is closely related to different psychological processes ; P300 was affected by the subjective probability chiefly on its amplitude but not on its latency.更多还原