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首页> 外文期刊>Journal of Neurophysiology >On the origin of the soleus H-reflex modulation pattern during human walking and its task-dependent differences.
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On the origin of the soleus H-reflex modulation pattern during human walking and its task-dependent differences.

机译：关于比目鱼H反射调制模式在人类行走过程中的起源及其与任务有关的差异。

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Recently, Brooke and colleagues have suggested "that the strong inhibition arising from passive movement about the knee and hip joints, lays down the base for the soleus H-reflex gain modulation seen during human gait." In particular stretch-evoked afferent activity from the quadriceps muscle was emphasized as the most important source of movement-induced inhibition of the H-reflex. To test this hypothesis we examined the kinematics and electromyographic (EMG) activity of the leg during human walking and correlated these with the modulation pattern of the soleus H-reflex. To further test the possible contribution of stretch-evoked quadriceps afferent activity to the soleus H-reflex modulation pattern during walking different walking gaits were studied. In one condition subjects were asked to walk with their knee locked in full extension by a rigid knee brace. In a second condition subjects were asked to walk backwards. During normal walking, the soleus H-reflex modulation pattern is strongly correlated with the EMG events of the soleus and tibialis anterior (TA), but not with hip, knee, or ankle angular displacement or velocity. When subjects walked with the knee locked in full extension, the amplitude of the H-reflex, its modulation pattern, and the task-dependent changes of its amplitude were the same as during normal walking. During backward walking, the H-reflex increases in late swing before activity of the soleus has begun and while the knee is flexing, an observation that highlights central control of the H-reflex amplitude. The effects of imposed flexion of the knee in passive subjects were also reexamined. The knee flexion imposed by the experimenter followed the same trajectory as that which occurred during the swing phase of the subject's step cycle. It was found that imposed knee flexions elicited a burst of TA EMG activity with an average latency of 81.6 ms (SD = 21 ms) in six out of eight subjects. Inhibition of the H-reflex, when it occurred, was associated with the occurrence of this burst. When subjects voluntarily flexed their right knee from an initial quiet standing posture, the inhibition of the soleus H-reflex began before flexion of the knee or that of any other leg segment. Once again the onset of inhibition was closely associated with the onset of activity in the TA. In the discussion section the present observations are examined in light of the predictions made by the movement-induced inhibition hypothesis of Brooke et al. It will be concluded that none of the predictions of this hypothesis were corroborated by present tests done during human walking. In consequence, we suggest that the modulation pattern of the H-reflex observed during normal human walking is centrally determined, as are the task-dependent differences of its amplitude (e.g., standing versus the stance phase of human walking).
机译：最近，布鲁克和同事们提出“膝关节和髋关节被动运动引起的强烈抑制作用，奠定了人类步态中比目鱼H反射增益调节的基础。”尤其强调了股四头肌拉伸诱发的传入活动是运动引起的H反射抑制的最重要来源。为了验证该假设，我们检查了人类步行过程中腿部的运动学和肌电图（EMG）活动，并将其与比目鱼H反射的调制模式相关联。为了进一步测试在不同的步态行走过程中，拉伸诱发的股四头肌传入活动对比目鱼H-反射调制模式的可能贡献，进行了研究。在一种情况下，受试者被要求通过坚硬的膝盖支架将膝盖锁定在完全伸展的状态下行走。在第二种情况下，要求受试者向后走。在正常的步行过程中，比目鱼H反射调制模式与比目鱼肌和胫骨前肌（TA）的EMG事件密切相关，但与臀部，膝盖或踝关节的角位移或速度无关。当受试者在膝盖完全伸展的情况下行走时，H反射的幅度，其调制模式以及与任务有关的幅度变化与正常行走时相同。在向后行走过程中，比目鱼活动开始之前和膝部弯曲时，H反射在后期挥杆中增加，这一观察突出了H反射振幅的中央控制。还重新检查了被动受试者膝部屈曲的影响。实验者施加的膝盖屈曲遵循的轨迹与受试者步伐周期的摆动阶段所发生的轨迹相同。发现八名受试者中有六名屈膝屈曲引起TA EMG活动爆发，平均潜伏期为81.6毫秒（SD = 21毫秒）。发生H反射时，其抑制作用与爆发的发生有关。当受试者从最初的安静站立姿势自愿屈曲右膝时，比目鱼H反射的抑制作用开始于屈膝或其他任何腿部屈曲之前。抑制的发作再次与TA中活性的发作紧密相关。在讨论部分中，根据Brooke等人的运动诱发抑制假说所作的预测，对本观察结果进行了研究。将得出的结论是，该假设的任何预测都不能通过在人类步行过程中进行的当前测试得到证实。因此，我们建议集中确定在正常人的行走过程中观察到的H反射的调制模式，以及其幅度依赖于任务的差异（例如，站立与人行走的站立阶段之间的差异）。

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