Domingo Antoinette, Klimstra Marc, Nakajima Tsuyoshi, Lam Tania, Hundza Sandra R
a School of Kinesiology, University of British Columbia , Vancouver , Canada.
J Mot Behav. 2014;46(1):49-57. doi: 10.1080/00222895.2013.854731. Epub 2013 Dec 7.
It is well established that remote whole-limb rhythmic movement (e.g., cycling or stepping) induces suppression of the Hoffman (H-) reflex evoked in stationary limbs. However, the dependence of reflex amplitude on the phase of the movement cycle (i.e., phase-dependence) has not been consistent across this previous research. The authors investigated the phase-dependence of flexor carpi radialis (FCR) H-reflex amplitudes during active walking and in kinematically matched static postures across the gait cycle. FCR H-reflexes were elicited in the stationary forearm with electrical stimulation to the median nerve. Significant phase-dependent modulation occurred during walking when the gait cycle was examined with adequate phase resolution. The suppression was greatest during midstance and midswing, suggesting increased ascending communication during these phases. There was no phase-dependent modulation in static standing postures and no correlation between lower limb background electromyography levels and H-reflex amplitude during active walking. This evidence, along with previous research demonstrating no phase modulation during passive walking, suggests that afferent feedback associated with joint position and leg muscle activation levels are not the sole source of the phase modulation seen during active walking. Possible sources of phase modulation include combinations of afferent feedback related to active movement or central motor commands or both.
众所周知，远程全肢节律性运动（如骑自行车或踏步）会抑制静止肢体中诱发的霍夫曼（H-）反射。然而，在以往的这项研究中，反射幅度对运动周期阶段的依赖性（即相位依赖性）并不一致。作者研究了在主动步行过程中以及在整个步态周期中运动学匹配的静态姿势下桡侧腕屈肌（FCR）H反射幅度的相位依赖性。通过对正中神经进行电刺激，在静止的前臂中诱发FCR H反射。当以足够的相位分辨率检查步态周期时，步行过程中出现了显著的相位依赖性调制。在支撑中期和摆动中期抑制作用最大，表明在这些阶段上行传导增加。在静态站立姿势中没有相位依赖性调制，并且在主动步行过程中下肢背景肌电图水平与H反射幅度之间没有相关性。这一证据，以及先前研究表明被动步行过程中没有相位调制，表明与关节位置和腿部肌肉激活水平相关的传入反馈不是主动步行过程中所见相位调制的唯一来源。相位调制的可能来源包括与主动运动相关的传入反馈或中枢运动指令或两者的组合。
