＋Gx作用对视觉－运动反应的影响

Effect of十Gx Stress on Visual-motor Reaction

为了研究＋Ｇｘ作用对视觉－运动反应的影响，６名健康男性青年在人体离心机上，承受＋３Ｇｘ、＋５Ｇｘ和＋７Ｇｘ作用时，进行视觉－运动反应操作。结果表明，随着超重值的增大，被试者简单视觉－运动反应时延长，漏反应次数增多，反应时概率分布曲线发生了偏移。当被试者进行视觉辨别～运动反操作时，除反应时的变化同简单反应时的变化大同小异外，还观察到了随Ｇ值的增加漏反应和误操作次数增多的现象，感觉敏感性指数逐渐变小，决策标准指数在低Ｇ值时基本不变，在＋７Ｇｘ时增加明显。此外，心率和呼吸频率有随Ｇ值增加而增大的趋势。这表明在＋Ｇｘ作用时人的监控能力受到了一定程度的损害。

Monitoring and discriminating performances were done in six malehealthy volunteers(aged l8～23 years and passed the required physical examinations).The subject sat in a contour couch with 20°backangle in the gondola of a human cen-trifuge with l2 meter radius. A visual-motor system was used ,it comprised a single-board computer, an LED array display placed 70cm in front of the subject, a tapere-corder, a printer and a specially desiged finger一tip controller placed on the subjects ab-domen. The G strcss was+Gx of trapezoidal profile having plateaus of+3Gx、+5Gxand+7Gx with duration of 90s. The subject’s task was to complete simple visual-motorand discriminating visual-motor reactions during +Gx exposures.It was found that:(1)with the increase of G level ,reaction time for both simple visual-motor reaction and dis-criminating visual-motor reaction increased;(2) probability distribution of simple visual-motor reaction time changed;(3)number of missed reactions and incorrect reactions in-creased.Indexes of sensitivity of observation and detection criteria were calculated usingsignal detecting theory(SDT).It was found that both of the indexes were impaired du-ring+Gx exposures. Besides ,heart rate and respiration rate as parameters of psycho-physiological load also increased with increase of G levei. The results showed that visual-motor performance was impaired significantly under+Gx stress。 Its cause was analysedand explained.