Misiaszek J E, Brooke J D, Lafferty K B, Cheng J, Staines W R
Biophysics Interdepartmental Group, University of Guelph, Ont., Canada.
Brain Res. 1995 Apr 17;677(1):69-81. doi: 10.1016/0006-8993(95)00126-b.
Human soleus H reflexes are attenuated during passive pedalling movements. This depression occurs within 70 ms of movement onset. We hypothesized that the reflex gain would return to control values with a similar brevity following movement. However, H reflexes sampled following a slow (10 rpm) passive pedalling movement of a single leg remained below control values for the duration of a 200 ms collection period, for all four pedal positions tested. The extent of the attenuation after movement was position dependent in a manner similar to that observed during movement. This position effect was more precisely defined by sampling reflexes 200 ms post-movement at 10 pedal crank positions. Also, the full course of reflex recovery was investigated by sampling up to 8 s post-movement at four pedal positions. Reflex gain remained reduced 1-4 s post-movement, in a position dependent manner. There was a subsequent facilitation of the reflex. Thus, following a locomotor-like movement there is sustained attenuation of the soleus H reflex. The early post-movement period is likely the continued expression of movement-induced reflex inhibition while the later period may arise from descending influences consequent to the termination of movement. Presynaptic inhibition is implicated, as reflexes still showed the gain modulation when sampled while soleus was tonically contracted, both following and during the passive movement.
在被动蹬踏运动期间，人类比目鱼肌的H反射会减弱。这种抑制在运动开始后70毫秒内出现。我们假设运动后反射增益会在类似的短时间内恢复到对照值。然而，在单腿进行缓慢（10转/分钟）被动蹬踏运动后采集的H反射，在200毫秒的采集期内，对于所有测试的四个踏板位置，其值都低于对照值。运动后衰减的程度与运动期间观察到的情况类似，与位置有关。通过在运动后200毫秒对10个踏板曲柄位置的反射进行采样，更精确地定义了这种位置效应。此外，通过在四个踏板位置对运动后长达8秒的反射进行采样，研究了反射恢复的全过程。运动后1至4秒，反射增益仍以位置依赖的方式降低。随后出现了反射的易化。因此，在类似运动的活动后，比目鱼肌H反射会持续衰减。运动后的早期阶段可能是运动诱导的反射抑制的持续表现，而后期阶段可能源于运动终止后的下行影响。由于在被动运动之后和期间，当比目鱼肌进行强直性收缩时采样，反射仍显示出增益调制，因此涉及突触前抑制。
