规律短音中极短间隔短音诱发的失匹配负电位

失匹配负电位是听觉事件相关电位的一个成分,它由一系列重复的,同性质的“标准刺激”的物理性质稍有偏离的“偏差刺激”所诱发,在规律性的标准刺激中,偶然的物理性质稍有偏离的刺激,如频率,强度,久度等的些微变化均可诱发ＭＭＮ。偶然地给于时间上“过早出现”的同样刺激,即频率,强度,久度完全相同,只是在规律性的标准刺激中过早地出现的刺激,作为偏差刺激,也可以诱发出ＮＮＭ。本研究在恒定刺激间隔ＩＳＩ＝６００ｍｓ

MISMATCH NEGATIVITY (MMN) TO VERY SHORT INTERVAL BETWEEN REGULAR TONES

The Mismatch Negativity(MMN)component of the auditory event--related potential(AERP)is elicited by infrequent,physically "deviantll stimuli in a sequence of frequent homogeneous stimuli("lstandardl"),for instance, by a change in frequency,intencity of duration etc.When the inter-stimulus interval (ISI)of tone pips was occasionally shortened either to 300,150,75,60 and 52 ms from regular ISI 600 ms,which resulted in the elicitation of MMN.The amplitude of MMN elicited by occasional shorter ISI was not reduced as a function of ISI shortening.This indicates that the MMN is not just due to activation of new afferent elements by deviant stimulus.Thus,by no means the elicitation of the MMN can be explained on the basis of the refractoriness.