Funase K, Imanaka K, Nishihira Y, Araki H
School of Allied Medical Sciences, Nagasaki University, Japan.
Eur J Appl Physiol Occup Physiol. 1994;69(1):21-5. doi: 10.1007/BF00867922.
In the present study, we investigated whether weak (10% of maximal voluntary contraction) tonic dorsiflexion (DF) and plantarflexion (PF) affects the two conventional parameters used for evaluating the excitability of the soleus motoneuron (MN) pool, i.e. the ratio of the threshold of H-reflex to that of M-response (Hth:Mth) and the ratio of the maximal amplitude of H-reflex to that of M-response (Hmax:Mmax) in human subjects. The results showed that the Hmax:Mmax decreased during DF and increased during PF compared with that during rest, whereas no clear alteration was observed in Hth:Mth. These results are consistent with the scheme proposed by earlier workers, who have argued that neither inhibitory nor facilitatory effects of the conditioning stimulus apply to specific spinal reflex circuits occurring around the threshold of the test H-reflex. It is suggested, therefore, that the conventional use of the Hth:Mth ratio as a parameter reflecting the excitability of the MN pool should be reconsidered.
在本研究中，我们调查了弱的（最大自主收缩的10%）强直性背屈（DF）和跖屈（PF）是否会影响用于评估比目鱼肌运动神经元（MN）池兴奋性的两个传统参数，即人类受试者中H反射阈值与M反应阈值之比（Hth:Mth）以及H反射最大幅度与M反应最大幅度之比（Hmax:Mmax）。结果显示，与静息时相比，DF期间Hmax:Mmax降低，PF期间Hmax:Mmax升高，而Hth:Mth未观察到明显变化。这些结果与早期研究者提出的方案一致，他们认为条件刺激的抑制或易化作用均不适用于在测试H反射阈值附近发生的特定脊髓反射回路。因此，有人建议，应重新考虑将Hth:Mth比值作为反映MN池兴奋性的参数的传统用法。
