模拟失重对快慢反应被试视觉选择注意ERPs的不同影响

Comparison of Effects of Simulated Weightlessness on ERPs in Fast and Slow Reaction Groups

目的研究模拟失重对不同反应类型被试者脑功能影响的差异。方法14名右利手正常被试者。以头低位倾斜(-10°,HDT)为模拟失重,头高位倾斜(+20°,HUT)为对照。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,在被试者中交叉规定)进行方位区分反应(DR),忽略非靶刺激。每种体位2h,均作5套DR测试。记录9导脑电。结果1)根据反应时的长短将被试者分成快反应(n=7)和慢反应(n=7)两组,其事件相关电位(ERPs)的主要差异表现为快反应组的N1和P3的幅值更大、前脑区负向慢波NSW的潜伏期更短、幅值更大,提示快反应被试者的觉醒水平和注意程度较高、主动抑制能力较强,脑功能状态较好;2)HDT引起ERPs中P2和P3成分幅值的降低,慢反应组ERPs受HDT影响的程度比快反应组更显著。结论模拟失重对慢反应被试者ERPs的影响更严重,为航天脑功能的评价和航天员的选拔提供了一定的实验依据。

Objective To study different effect of 2h simulated weightlessness between two types of event-related brain potentials （ERPs） during visual selective discrimination. Method The stimuli consisted of two-color LED flashes appeared randomly in left （LVF） or right （RVF） visual field with same probability. Fourteen normal subjects were asked to make switch response to target signals （T） differentially, switching to left for T in LVF and to right for T in RVF, and make no response to non-target signals （N）. Five sets of tests were made during head down tilt （HDT, -10°） and head up tilt （HUT, ＋20°）, respectively. ERPs were obtained from 9 locations on the scalp. Result 1） The subjects could be devided into fast （FR, n =7） and slow （SR, n =7） reaction groups [reaction time： （450.2 ±46.7）ms and （571.2 ±42.8） ms, P 〈0. 001, respectively]. The difference of reactions between the two groups was mainly that the amplitudes of N1 and P3 components in FR group were more larger than those in SR group, and the latency of negative slow wave （NSW） at frontal area in FR group was shortern; 2） Compared with reactions during HUT, the mean amplitude （P2-P3） decreased and more significant in FR group than that in SR group during HDT. Conclusion These data provide further evidence showing that higher brain function was affected by simulated weightlessness, especially to slow reaction subjects. It provides scientific basis for the evaluation of space brain function and the selection of astronaut.