WMN：非靶刺激加工过程中一个与工作记忆相关的视觉ERPs负成分

目的通过比较复杂程度不同的视觉作业中的非靶ERPs特征 ,探讨脑对非靶刺激的加工机制。方法 2 6名健康青年男性被试者 [( 2 1 .2± 3.3)岁 ]。刺激为等概率出现在左、右视场的红、绿闪光刺激 ,要求被试者对靶刺激 (红光或绿光 ,交叉规定 )进行拨开关 (SR)或方位区分 (DR) ,忽略非靶刺激。结果与SR相比 ,DR非靶ERPs在额区产生了 1 0 0～ 70 0ms的峰值在 380ms左右的负向慢波 -工作记忆负波(WMN ,workingmemorynegativity)。 结论ERPs负成分WMN的产生表明对非靶刺激除了感知加工过程 ,还可能涉及到对工作记忆中模式的消除和重新提取等脑活动过程 ,而这种脑活动主要发生在额区

WMN: A Negative ERPs Component Related to Working Memory during Non-target Visual Stimuli Processing

Objective To study non target stimuli processing in the brain. Method Features of the event related potentials (ERPs) from non target stimuli during selective response task (SR) was compared with that during visual selective discrimination (DR) task in 26 normal subjects. The stimuli consisted of two color LED flashes (red and green) appeared randomly in left (LVF) or right (RVF) visual field with same probability. ERPs were derived at 9 electrode sites on the scalp under 2 task conditions: a) SR, making switch response to the target (T) stimuli from LVF or RVF in one direction and making no response to the non target (NT) ones; b) DR, making switching response to T stimuli differentially, i.e., to the left for T from LVF and to the right for T from RVF. Result 1) the non target stimuli in DR conditions, compared with that in SR condition, elicited smaller P2 and P3 components and larger N2 component at the frontal brain areas; 2) a significant negative component, named as WMN (working memmory negativity), appeared in the non target ERPs during DR in the period of 100 to 700 ms post stimulation which was predominant at the frontal brain areas. Conclusion According to the major difference between brain activities for non target stimuli during SR and DR, the predominant appearance of WMN at the frontal brain areas demonstrated that the non target stimulus processing was an active process and was related to working memory, i.e., the temporary elimination and the retrieval of the response mode which was stored in working memory.