“计数”和“不计数”状态下300ms处电位研究

Auditory 300 ms Potential in "Counting" and" non-Counting" methods

文中观察了１０名健康飞行员在“计数”和“不计数”状态下３００ｍｓ的电位情况。采用新异的声刺激模式，小概率靶刺激信号为２ｋＨｚ短音（占２０％），大概率非靶刺激信号为１ｋＨ２短音（占８０％）。测试方式分为“计数”、“不计数”两种，分别测定靶与非靶刺激所诱发的３００ｍｓ处电位，并计算二者相减所得差异负波各参数。结果显示：“计数”状态下，比“不计数”状态下Ｐ３００的潜伏期为短，波幅为大，Ｐ３００反映了选择性注意时脑控制性加工过程。而“不计数”状态下的差异负波的基线上面积，虽较“计数”状态时为小，但仍清晰可辨。差异负波包括失匹配负电位（ＭＭＮ）和／或Ｎ２ａ，属外源性电位，反映了被动注意时脑自动加工过程。作者认为Ｐ３００及差异负波可分别作为“计数”与“不计数”测试指标，有可能客观而无创性地对中枢听觉脑认知功能作出评估，具有一定的临床应用价值。

This study observed the effects of different counting manners on the 300 ms potential.It was elicited by nontarget(l kHz,80%)and target (deviant)(2 kHz,20%)stimuli in an auditory oddball paradigm for l0 healthy subjects.The results showed that the latencies of P300 were the shortest,amplitude was larger in 'counting' manner than the 'non-counting'manner。But the different negative waves elicited clearly even in' non-counting'manner,through its area above base line was smaller than that in the' manner.The different negative wave consisted in mismatch negativity(MMN) and N2a potential was an exogenous component elicited in autornatic processing,while P300 was an endogenous component elicited,especially in' counting'and 'non-counting'methods,these P 300 and different negative wave may be considered an objective and noninvasive clinical measure for assessing central auditory cognitive brain function。