坐位下体负压对人体脑功能影响的实验研究

Effects of lower body negative pressure in upright seated position on human brain function

目的 探讨坐位下体负压 (Lowerbodynegativepressure,LBNP)暴露时对人体脑功能的影响。方法 15例健康青年男性被试者在坐位LBNP - 4.0 0kPa(- 30mmHg)、- 6 .6 7kPa(- 5 0mmHg)的条件下 ,分别测试暴露前、暴露时和卸压后的脑事件相关电位 (Eventrelatedpotential,ERP)P3 0 0 、反应时 (Reactiontime ,RT)及跟踪误差 (Trackingerror,TrE)等工效学指标 ,并记录主观症状。结果 在 - 4.0 0kPaLBNP作用时 ,P3 0 0 波幅、潜时、反应时、跟踪误差与负压前对照差异无显著性意义 (P >0 0 5 )。在 - 6 .6 7kPaLBNP作用时 ,P3 0 0 波幅降低 (P <0 .0 1) ,P3 0 0 潜时延长 (P <0 .0 1) ,反应时延长 (P <0 .0 5 ) ,跟踪误差增大 (P <0 .0 5 )。主观症状随着负压值的增大 ,症状数量增多 ,程度加重。结论 坐位下体负压造成血液在下肢积聚 ,引起大脑供血量减少 ,从而引起大脑对外界的反应减慢 。

Objective To investigate the effects of different lower body negative pressures(LBNP) in upright seated position on human brain function.Methods Fifteen young men were selected as subjects.P 300 amplitude and latency,reaction time(RT),tracking error(TrE) and subjective symptoms were recorded at LBNP of -4.00 kPa(-30mmHg) and -6.67 kPa(-50mmHg) in upright seated position.Results At -4.00 kPa,P 300 amplitude and latency,RT and TrE had no significant differences,compared with controls;Subjective symptoms were transient and slight.At -6.67 kPa,P 300 amplitude decreased(P<0.01),P 300 latency and RT prolonged(P<0.01,P<0.05),TrE increased(P<0.05),and subjective symptoms angmented and were aggravated,compared with -4.00 kPa.Conclusions LBNP causes hypostasis in lower legs,decreasing the blood supply to the brain,and making the brain reactvslowly to ambient stimuli and its cognitive capacity diminished.