不同心理刺激诱发的交感和副交感神经活动的比较

The Effect of Different Psychological Stressorson Responses of Sympathetic and Parasympathetic Nervous Systems

让24名女大学生被试完成划消测验、镜画测验、心算和准备演讲四种应激任务,目的在于探讨在不同心理刺激下交感和副交感神经系统的活动是否存在差异。记录HRV(Heart Rate Variability,心率变异性)的频域成分TP(Total Power,总功率)、HF(High Frequency,高频)、LF(Low Frequency,低频)、LF/HF(低频高频比)、平均R-R间期和血压等指标在基线和不同应激任务期间的变化。通过单因素重复测量方差分析和多重比较发现,准备演讲期间的TP、LF值显著地高于基线和其它三项任务,HF的值显著地高于划消测验和心算;镜画测验、划消测验和心算期间的LF值与基线比较显著下降,TP、LF和HF三项指标在这三项任务之间无显著差异;不同任务期间在LF/HF上无显著主效应。平均R-R间期基线水平与所有任务间的比较及各任务之间有显著差异。收缩压基线水平与划消、镜画任务间的比较有显著差异。结果表明,准备演讲期间的交感神经和副交感神经张力显著地大于其它任务,不同任务表现出的不同的自主神经张力变化说明交感神经与副交感神经活动不是一方活动增强、另一方活动减弱的单纯的活动方式,这一结果为Berntson提出的自主神经活动可能存在九种活动搭配模式的理论提供了实验证据。

Introduction Studies indicated that psychological stress may result in increase or decrease in target - specific sympathetic outputs, increase or decrease in certain vagal outputs. The altered responses may be less efficient and less adaptive and, thus, on a long - term basis, unfavorable to health. Evidence of disordered autonomic function has also been observed in patients with various somatic disorders, for instance, functional bowel disorders headaches, or cardiac arrhythrnias. In order to clarify the relations between psychological stress and autonomic nervous system, in the present study, we examined the effect of different psychological stressors on the sympathetic and parasympathetic activities and other cardiovascular activities. Method Twenty four healthy female undergraduates participated in the study. The participants were requested to complete baseline rest, cancellation test, mirror - tracing task, arithmetic task and speech - preparation, and simultaneously recorded spectrum domain of HRV（ TP： total power, HF： high frequency, LF： low frequency and LF/HF： low - to high - frequency ratio）, averaged R - R interval and blood pressure. The different components of HRV allow to observe sympathetic and parasympathetic function non- invasively and independently of each other. The data obtained were analyzed by SPSS 10.0. The order of the stressors presentation were counterbalanced in order to avoid order effect. Results One - way analysis of variance for repeated measures showed the values of TP and LF during speech - preparation were significantly increased than baseline and other tasks, HF was increased significantly than cancellation test and arithmetic and there was no difference compared to baseline. During other three tasks LF decreased compared to baseline, the values of TP, LF and HF were no difference between them. The values of LF/ HF didn＇ t show main effect between any tasks. Compared to the baseline,any of the four psychological stressors induced a decrease for Averaged R - R interval, and an increase for the systolic pressure. No differences were observed for the diastolic pressure. Subjective experience of stress was not consistent with its physiological responses. Conclusion The findings indicated that the activities in sympathetic nervous system （SNS） and parasympathetic nervous system （PNS） decreased during cancellation test, mirror - tracing task and arithmetic task. However, the activities of SNS and PNS during speech - preparation was stronger than other tasks. The autonomic nervous activities during speech - preparation were different from those on the other three tasks. Averaged R - R interval and Blood pressure were both sensitive to the differences between the baseline and the tasks. The differences of ANS activities during different tasks supported strongly for Berntson＇s theory that proposed there were nine changeable modes of ANS. It was still not clear that the mental mechanism resulted in such differences.