概率对冲突信息诱发的事件相关电位N270的影响

目的:研究刺激概率对颜色冲突信息诱发的事件相关电位N270的影响。方法:将四种颜色随机组合的刺激对分为三组:一组,在该组刺激中颜色相同的刺激对与不同的刺激对各占50％的概率;二组颜色不同的占85％,相同的占15％的概率;三组颜色不同的概率占15％,相同的占85％。受试者的任务:辨别前后呈现的两个刺激(第一个刺激S1,第二个刺激S2)颜色是否相同。结果:在颜色冲突(两个刺激颜色不同)事件中,S2刺激可诱发出一显著的事件相关电位负波(N270),该负波并不出现在非冲突事件中,且N270的振幅不受概率的影响。结论:N270是反映脑内特定冲突信息探知系统的神经电活动指标,与N2b不同,不受刺激概率的影响。

The effects of probabilities on event-related potential N270

Objective To observe the changes of event - related potential in different probability of conflicting information. Methods: Subjects were instructed to discriminate if the two stimulus spots presented in sequence on screen were of the same color. The stimulus pairs were divided into three groups: 1, The matched and non -matched stimulus pairs were of the same probability, 50% respectively. 2, The probability of non -matched color pairs was 85% but the other was 15%. 3, The probability of non -matched color stimulus pairs was 15%, but the other was 85%. Result; A remarkable negativity (N270) was recorded from all scalp electrodes in the conflicting stimulus pairs (non - matched) rather than the matching stimulus pairs. N270 amplitude was not influenced by the probability of the stimulus pairs. Conclusion: There exists a specific system to process the conflicting information in the brain.