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在平衡扰动期间比目鱼肌肌电图活动变化之前的H反射调制。

H-reflex modulation preceding changes in soleus EMG activity during balance perturbation.

作者信息

Miranda Zoé, Pham Annie, Elgbeili Guillaume, Barthélemy Dorothy

机构信息

Faculty of Medicine, School of Rehabilitation, Université de Montréal, Pavillon du Parc, C.P.6128 Succ. Centre-ville, Montreal, QC, H3C 3J7, Canada.

Centre for Interdisciplinary Research in Rehabilitation of Greater Montreal, CRIR, Montreal, Canada.

出版信息

Exp Brain Res. 2019 Mar;237(3):777-791. doi: 10.1007/s00221-018-5459-0. Epub 2019 Jan 2.

Abstract

When balance is compromised, postural strategies are induced to quickly recover from the perturbation. However, neuronal mechanisms underlying these strategies are not fully understood. Here, we assessed the amplitude of the soleus (SOL) H-reflex during forward and backward tilts of the support surface during standing (n = 15 healthy participants). Electrical stimulation of the tibial nerve was applied randomly before platform tilt (control) and 0, 25, 50, 75, 100 or 200 ms after tilt onset. During backward tilt, a significant decrease in H-reflex amplitude was observed at 75, 100 and 200 ms. The onset of the decreased H-reflex amplitude significantly preceded the onset of the SOL EMG decrease (latency: 144 ± 16 ms). During forward tilt, the amplitude of the H-reflex increased at 100 and 200 ms after tilt onset. The onset of H-reflex increase did not occur significantly earlier than the onset of the SOL EMG increase (127 ± 5 ms). An important inter-subject variability was observed for the onset of H-reflex modulation with respect to EMG response for each direction of tilt, but this variability could not be explained by the subject's height. Taken together, the results establish the time course of change in SOL H-reflex excitability and its relation to the increase and decrease in SOL EMG activity during forward and backward tilts. The data presented here also suggest that balance mechanisms may differ between forward and backward tilts.

摘要

当平衡受到损害时,会诱发姿势策略以便从干扰中快速恢复。然而,这些策略背后的神经机制尚未完全明了。在此,我们评估了站立时支撑面进行前后倾斜过程中比目鱼肌(SOL)H反射的幅度(n = 15名健康参与者)。在平台倾斜前(对照)以及倾斜开始后0、25、50、75、100或200毫秒随机施加胫神经电刺激。在向后倾斜过程中,在75、100和200毫秒时观察到H反射幅度显著降低。H反射幅度降低的起始明显早于SOL肌电图降低的起始(潜伏期:144±16毫秒)。在向前倾斜过程中,倾斜开始后100和200毫秒时H反射幅度增加。H反射增加的起始并不比SOL肌电图增加的起始显著更早(127±5毫秒)。对于每个倾斜方向,H反射调制相对于肌电图反应的起始观察到重要的个体间变异性,但这种变异性无法用受试者的身高来解释。综上所述,结果确定了前后倾斜过程中SOL H反射兴奋性变化的时间进程及其与SOL肌电图活动增减的关系。此处呈现的数据还表明,前后倾斜之间的平衡机制可能有所不同。

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