听觉时间感知的事件相关电位P250的发现  

The Event-related Potential P250 Evoked by the Time Perception

作　　者：刘瑾[1] 王明时[1] 王力群 刘忠国[1] 诸强[1] 

机构地区：[1]天津大学精密测试技术及仪器国家重点实验室,天津300072 [2]日本东京电机大学超电导应用研究所高技术研究中心

出　　处：《中国生物医学工程学报》2006年第6期667-671,共5页Chinese Journal of Biomedical Engineering

基　　金：国家自然科学基金资助项目(30170308)。

摘　　要：探讨大脑对时间信息的处理过程,考察了大脑在由声音标记的时间间隔长短感知过程中的事件相关电位变化,从电生理角度揭示出大脑对时间这一信息的处理过程。实验包括无任务和间隔长短辨识任务,间隔长短辨识任务要求受试者在两种时间间隔(四个声音信号)结束后进行长短判断。结果发现无任务状态下各声音信号诱发的听觉诱发电位与正常的听觉诱发电位无显著性差异。而间隔长短辨识任务的结果表明,时间间隔判别任务中待判别间隔(第二个间隔)较给定间隔(第一个间隔)短时,在两间隔结束时即第四个声音信号的诱发电位与无任务实验的结果出现显著变化,在200ms^300ms左右诱发出一个明显的正峰,称其为P250(因峰值出现在250ms左右),同时,此声音诱发的P2显著被抑制,甚至消失;但是待判别间隔较给定间隔长时,则无显著性差异,原因在于在较长的第四个声音信号结束之前大脑已经判断完毕并作出了决策,从而无法诱发出P250。提示大脑对时间信息的比较判断引发了一个新的电位P250。The brain activity was studied in this paper when people processed the time information by analyzing the event-related potentials of the time perception evoked by a pair of intervals signed by four sounds. The experiments included nontask and judging task. In the former task subjects passively listened to the sounds regardless the time intervals. In the latter task the subjects compared two time intervals in a group and responded by pressing two different keys at the end of last sound. The two tasks had the same procedure of stimuli. The results indicated that the evoked potentials of nontask were same approximately with the normal evoked potentials. And in the judging task the EP corresponded to fourth sound, in which a positive wave named P250 appeared around 200ms - 300ms and the P2 was inhibited apparently, differed significantly with in nontask while the second interval was shorter than the first. The P250 did not appear while the second interval was longer than the first one since the result of judging was clear already before the present of last sound. The conclusion was that the brain activity evoked a new EP component P250 in the udging process of time information.

关 键 词：时间感知 事件相关电位 P250 时间间隔 

分 类 号：R318[医药卫生—生物医学工程]