方向信息冲突诱发的事件相关电位

Event related potential induced by orientation information conflict

waveamplitudeishuge.TheorientaproductionofN270.目的:使用事件相关电位技术,探讨人脑处理方向信息冲突的工作机制。方法:选择首都医科大学的在读本科生10名(6名男生,年龄21～24岁)作为健康受试者(经书面同意),进行人脑对方向冲突的反应的观察。成对的相同动物图片(S1和S2)在屏幕上依次呈现。S1和S2都向左时称为左-左状态(状态1),S1和S2都向右时称为右-右状态(状态2),以上两种状态均视为匹配状态;当S1方向向左而S2向右时称为左-右状态(状态3),反之称为右-左状态(状态4),后两种状态则视为冲突状态。受试者的任务是判断成对出现的S1和S2出现方向是否相同,无论S1方向向左还是向右。采用美国Neuroscan脑电诱发电位工作站在给出刺激的同时在头皮记录事件相关电位存储在硬盘,经离线式叠加处理后分别对各成分进行不同状态间平均电压的比较。结果:10名被试的实验数据全部纳入分析统计。①4种状态(左-左状态、右-右状态、左-右状态和右-左状态)的反应时依次为(577±161)ms、(581±173)ms、(586±100)ms和(594±103)ms,正确率均为99%,差异无显著性意义[F(1,9)=8.94,P>0.05];[F(1,9)=13.87,P>0.05]。②全部4种状态均记录到由S2诱发的P100、N170、N200和P300,冲突状态下电极广泛记录到N270,在前头部额中央区明显。③分别对4种状态下各成分的平均波幅进行双因素方差分析显示:各成分的平均波幅在两种匹配状态和两种冲突状态之间差异均无显著性意义;与匹配状态相比,冲突状态下顶枕部P100和右侧额部P300平均波幅显著增高,右侧顶部和颞部N270平均波幅明显高于左侧;P300的平均波幅在匹配状态下,左侧顶部较右侧顶部高,而在冲突状态下,左右侧顶部的平均波幅差异无显著性意义。结论:当一对刺激的方向不同时,在增强的P100(P1)后可记录到一个明显的负波-N270,波幅以前头部较大。方向信息冲突可以诱发N270的产生。

AIM： To explore the processing mechanism of human brain for orientation conflict with event related potential technique. METHODS： Totally 10 undergraduate students who were studying for Bachelor＇s degree （six males, 21-24 years） from Capital University of Medical Sciences were enrolled as healthy examinees （after signed the informed consent） to observe the response of human brain for orientation conflict. Paired pictures as visual stimuli （S1 and S2） presented sequentially in the computer screen in front of the subjects. S1 and S2 were the same orientated left （condition 1）; paired stimuli were both orientated right （condition 2）; Above two conditions were paired state. S1 was orientated left and S2 was orientated right （condition 3）; S1 was orientated right and S2 was orientated left （condition 4）; Latter two conditions were conflict state. Subjects were required to judge whether S2 was the same orientation to S1 under the four conditions, while event related potentials were recorded on their scalps and stored on a hard disk at the same time of stimulating given by American Neuroscan brainelectricity evoked potential workstation. Mean voltage at different state was compared after disposal with off-line analysis. RESULTS： Experimental data of 10 examinees were involved in the analysis statistics. ①Reaction times of the 4 states （condition 1, 2, 3 and 4） were （577＊161） ms, （581＊173） ms, （586＊100） ms and （594＊103） ms with the accuracy of 99%, which had insignificant difference [F（1.9）=8.94, P〉 0.05];[F（1.9）=13.87,P 〉 0.05]. ②Following the onset of S2, ERP components P100, N170, N200 and P300 were recorded in all conditions while in orientation conflicting conditions, N270 was evoked after an enlarged P100, it was mainly distributed at centra-frontal area. ③Average wave amplitude was analyzed in the four conditions with double factor analysis of variance： There was no significant difference in the mean amplitude of event related potential components neither between the paired conditions nor the two conflict conditions. The mean amplitudes of P100 at parieto-occipital area and P300 at right frontal area in conflict conditions were significantly more positive than those of in paired conditions. The mean amplitude of N270 at right centro-temporal area exceeded that of at the left in conflict conditions, and the mean amplitude of P300 at left pariietal area exceeded that of at the right in match conditions while the asymmetry was absent in conflict conditions. CONCLUSION： A significantly negative wave -N270 can be elicited after fortified P100（P1 ） when the irritative direction is different. Fore headof wave amplitude is huge. The orientation information conflict can induce the production of N270.