Shindo M, Harayama H, Kondo K, Yanagisawa N, Tanaka R
Exp Brain Res. 1984;53(2):400-8. doi: 10.1007/BF00238170.
Reciprocal Ia inhibition from ankle flexors to extensors was studied during voluntary tonic isometric dorsiflexion and plantar flexion in five normal subjects. The Ia inhibition was examined as the short-latency suppression of the soleus H-reflexes by stimulation of the low-threshold afferents in the common peroneal nerve (Mizuno et al. 1971). At rest, weak Ia inhibition was demonstrated in four subjects out of five, the maximal amount being 14.1 +/- 5.0% suppression of the control H-reflex. The absolute amount of inhibition, which was calculated by subtracting the mean size of the conditioned H-reflex from that of the control H-reflex and expressed as a percentage of the maximal M-response, increased during ankle dorsiflexion, and decreased or disappeared during plantar flexion in parallel with the amount of contraction. The neural mechanisms for facilitation of the Ia inhibitory pathway during dorsiflexion were considered to support the hypothesis of "alpha-gamma-linkage in reciprocal inhibition", i.e. combined facilitatory effects on the Ia inhibitory interneuron from the supraspinal centers directly and indirectly via the gamma motoneuron--Ia afferent route. The mechanism for inhibition of the pathway during plantar flexion was considered to be inhibition of the Ia interneuron of the flexor side by Ia interneuron of antagonist extensors. A quantitative aspect of activity in the reciprocal Ia inhibitory pathway on the performance of voluntary movement is revealed in this study.
在五名正常受试者进行自愿性等长背屈和跖屈时，研究了从踝部屈肌到伸肌的交互性Ia抑制。通过刺激腓总神经中的低阈值传入神经，将Ia抑制作为比目鱼肌H反射的短潜伏期抑制进行检测（水野等人，1971年）。静息时，五名受试者中有四名表现出微弱的Ia抑制，最大抑制量为对照H反射的14.1±5.0%。抑制的绝对量通过从对照H反射的平均大小中减去条件性H反射的平均大小来计算，并表示为最大M反应的百分比，在踝背屈时增加，在跖屈时随着收缩量的增加而减少或消失。背屈时Ia抑制通路促进的神经机制被认为支持“交互抑制中的α-γ联系”这一假说，即通过γ运动神经元-Ia传入途径，脊髓上中枢直接和间接对Ia抑制性中间神经元产生联合促进作用。跖屈时该通路抑制的机制被认为是拮抗伸肌的Ia中间神经元对屈肌侧的Ia中间神经元产生抑制作用。本研究揭示了交互性Ia抑制通路活动在自愿运动表现中的定量方面。
