Nakazawa Kimitaka, Miyoshi Tasuku, Sekiguchi Hirofumi, Nozaki Daichi, Akai Masami, Yano Hideo
Motor Control Section, Department of Motor Dysfunction, Research Institute, National Rehabilitation Center for the Disabled, 4-1 Namiki, Tokorozawa 359-8555, Japan.
Clin Neurophysiol. 2004 Jun;115(6):1296-304. doi: 10.1016/j.clinph.2004.01.016.
To investigate the effects of loading and unloading of the lower limb joints on the soleus H-reflex in standing humans.
H-reflexes were elicited in the soleus muscle in subjects standing on a force platform in a water tank under the following loading conditions of the ankle and knee joints: control condition; reduced loads of -10 and -20 N; imposed loads of 10 and 20 N. The joint loading was altered by changing the combinations of buoys and weights attached to the lower limb segments, while total body weight was kept constant.
As the ankle- or knee-joint load was reduced, the H-reflex was significantly enhanced compared to that under the control condition. In contrast, the H-reflex was decreased as the ankle- or knee-joint load was increased. In both cases, similar levels of background activity were recorded.
The present results suggest that joint afferents might mediate the suppression of the soleus H-reflex in standing humans. However, the identification of the receptors and/or the mechanisms cannot be addressed under the current experimental set up.
The results of this study give some basic insights into reflex control in an upright posture.
研究站立人体下肢关节的加载与卸载对比目鱼肌H反射的影响。
在水箱中的力平台上站立的受试者的比目鱼肌中引出H反射，踝关节和膝关节的加载条件如下：对照条件；-10 N和-20 N的减载；10 N和20 N的加载。通过改变附着于下肢节段的浮标和重量的组合来改变关节负荷，同时保持总体重不变。
与对照条件相比，随着踝关节或膝关节负荷的降低，H反射显著增强。相反，随着踝关节或膝关节负荷的增加，H反射降低。在两种情况下，记录到的背景活动水平相似。
目前的结果表明，关节传入神经可能介导站立人体中比目鱼肌H反射的抑制。然而，在当前的实验设置下，无法确定感受器和/或机制。
本研究结果为直立姿势下的反射控制提供了一些基本见解。
