Graduate School of Systems and Information Engineering, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573, Japan.
Exp Brain Res. 2010 Apr;202(2):385-95. doi: 10.1007/s00221-009-2145-2. Epub 2010 Jan 1.
We investigated the modulation of the soleus (Sol) Hoffmann (H-) reflex excitability by peripheral sensory inputs during passive stepping using a robotic-driven gait orthosis in healthy subjects and spinal cord-injured patients. The Sol H-reflex was evoked at standing and at six phases during passive stepping in 40 and 100% body weight unloaded conditions. The Sol H-reflex excitability was significantly inhibited during passive stepping when compared with standing posture at each unloaded condition. During passive stepping, the H-reflex amplitude was significantly smaller in the early- and mid-swing phases than in the stance phase, which was similar to the modulation pattern previously reported for normal walking. No significant differences were observed in the H-reflex amplitude between the two unloaded conditions during passive stepping. The reflex depression observed at the early part of the swing phase during passive stepping might be attributed to the sensory inputs elicited by flexion of the hip and knee joints. The present study provides evidence that peripheral sensory inputs have a significant role in phase-dependent modulation of the Sol H-reflex during walking, and that the Sol H-reflex excitability might be less affected by load-related afferents during walking.
我们使用机器人驱动的步态矫形器研究了健康受试者和脊髓损伤患者在被动步态时，外周感觉输入对比目鱼肌（Sol）Hoffmann（H-）反射兴奋性的调制作用。在 40%和 100%体重卸载条件下，在站立和被动步态的六个相位中诱发 Sol H 反射。与每个卸载条件下的站立姿势相比，被动步态时 Sol H 反射兴奋性显著受到抑制。在被动步态时，H 反射幅度在早期和中期摆动阶段明显小于站立阶段，这与正常行走时的调制模式相似。在被动步态时，两个卸载条件之间的 H 反射幅度没有观察到显著差异。在被动步态时，摆动早期观察到的反射抑制可能归因于髋关节和膝关节弯曲引起的感觉输入。本研究提供的证据表明，外周感觉输入在行走时对 Sol H 反射的时相关调制中起重要作用，并且在行走时，Sol H 反射兴奋性可能较少受到与负荷相关的传入的影响。
