Muscular responses and movement strategies during stumbling over obstacles
Muscular responses and movement strategies during stumbling over obstacles
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DOI：
10.1152/jn.2000.83.4.2093
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发表时间：
2000-04-01
影响因子：
2.5
通讯作者：
Duysens, J
中科院分区：
文献类型：
--
作者：
Schillings, AM;Van Wezel, BMH;Duysens, J
在障碍物绊倒时的肌肉反应和运动策略。神经生理学杂志。83：2093-2102，2000.尽管许多研究已经调查了皮肤或本体感觉传入刺激后的反射，但对更自然的扰动（例如绊倒障碍物）后的反应知之甚少，特别是这些反应的相位依赖性及其与绊倒行为的关系很少受到关注。因此，在步态摆动阶段的扰动后，在绊倒反应的反应策略进行了研究。当受试者在跑步机上行走时，一个坚硬的障碍物意外地阻碍了脚的向前摆动。所有受试者在早期摆动扰动后表现出“升高策略”，在晚期摆动扰动后表现出“降低策略”。在抬高策略期间，通过同侧股二头肌（iBF）反应辅助的额外膝关节屈曲和胫骨前肌（iTA）反应辅助的踝关节背屈，将脚直接抬过障碍物。随后，大的股直肌（iRF）激活诱导膝关节伸展，将脚放在跑步机上。在降低策略期间，将脚快速放置在跑步机上，并在随后的摆动中抬起越过障碍物。足部放置由与膝关节伸展和前摆减速相关的iRF和iBF反应主动控制。iTA的激活主要先于同侧比目鱼肌（ISO）的主要反应。对于这两种策略，可以区分四个响应峰，其延迟时间类似于40 ms（RP 1）、类似于75 ms（RP 2）、类似于110 ms（RP 3）和类似于160 ms（RP 4）。这些响应峰值的幅度取决于步进循环中的相位。相位依赖性调制的反应不能占刺激或背景活动的差异，因此被认为是前运动神经元的起源。在中间摇摆。升高和降低策略都可能发生。对于该阶段，可以在不存在阶段依赖性响应调制的情况下比较两种策略的响应。两种策略具有相同的初始肌电反应，直到扰动后100 ms（RP 1-RP 2）相似。最早的反应（RP 1）被认为是一个短潜伏期的拉伸反射引起的相当大的影响的碰撞，而第二（RP 2）的功能让人想起皮肤和本体感受的反应。这两种反应都不能决定行为反应策略。功能上重要的反应策略取决于后来的反应（RP 3-RP 3）。这些数据表明，在绊倒反应，作为第一道防线，中枢神经系统释放一个相对非特异性的反应，这是由一个适当的行为反应，以避免障碍。
Muscular responses and movement strategies during stumbling over obstacles. J. Neurophysiol. 83: 2093-2102, 2000. Although many studies have investigated reflexes after stimulation of either cutaneous or proprioceptive afferents, much less is known about responses after more natural perturbations, such as stumbling over an obstacle, in particular, the phase dependency of these responses and their relation to the stumbling behavior has received little attention. Hence response strategies during stumbling reactions after perturbations at different times in the swing phase of gait were studied. While subjects walked on a treadmill, a rigid obstacle unexpectedly obstructed the forward sway of the foot. All subjects showed an "elevating strategy" after early swing perturbations and a "lowering strategy" after late swing perturbations. During the elevating strategy, the foot was directly lifted over the obstacle through extra knee flexion assisted by ipsilateral biceps femoris (iBF) responses and ankle dorsiflexion assisted by tibialis anterior (iTA) responses. Later, large rectus femoris (iRF) activations induced knee extension to place the foot on the treadmill. During the lowering strategy, the foot was quickly placed on the treadmill and was lifted over the obstacle in the subsequent swing. Foot placement was actively controlled by iRF and iBF responses related to knee extension and deceleration of the forward sway. Activations of iTA mostly preceded the main ipsilateral soleus (iSO) responses. For both strategies, four response peaks could be distinguished with latencies of similar to 40 ms (RP1), similar to 75 ms (RP2), similar to 110 ms (RP3), and similar to 160 ms (RP4). The amplitudes of these response peaks depended on the phase in the step cycle. The phase-dependent modulation of the responses could not be accounted for by differences in stimulation or in background activity and therefore is assumed to be premotoneuronal in origin. In mid swing. both the elevating and lowering strategy could occur. For this phase, the responses of the two strategies could be compared in the absence of phase-dependent response modulation. Both strategies had the same initial electromyographic responses till similar to 100 ms (RP1-RP2) after perturbation. The earliest response (RP1) is assumed to be a short-latency stretch reflex evoked by the considerable impact of the collision, whereas the second (RP2) has features reminiscent of cutaneous and proprioceptive responses. Both these responses did not determine the behavioral response strategy. The functionally important response strategies depended on later responses (RP3-RP3). These data suggest that during stumbling reactions, as a first line of defense, the CNS releases a relatively aspecific response, which is Followed by an appropriate behavioral response to avoid the obstacle.