Ashby P, Verrier M, Lightfoot E
J Neurol Neurosurg Psychiatry. 1974 Dec;37(12):1352-60. doi: 10.1136/jnnp.37.12.1352.
Activity in three segmental pathways was compared in normal subjects, patients with spinal shock, and patients with established spinal spasticity. The Achilles tendon reflex (ATR) was used to estimate transmission in the Ia monosynaptic pathway. Evidence is produced implying that vibration activates motoneurones principally through a polysynaptic pathway. The tonic vibration reflex (TVR) was used to estimate transmission in this Ia polysynaptic pathway. The percentage of the motoneurone pool (M-response) that could be activated by these pathways was used as a measure of transmission. The H reflex (vibration)/H reflex (control) ratio was used as an estimate of the degree of presynaptic inhibition of the Ia monosynaptic pathway. The findings led to the following conclusions. (1) In spinal shock presynaptic inhibition is greater than normal, transmission in the Ia monosynaptic pathway is reduced, and in the Ia polysynaptic pathway virtually abolished. (2) In established spasticity presynaptic inhibition is impaired, transmission in the Ia monosynaptic pathway is increased, but transmission in the Ia polysynaptic pathway never recovers. (3) The failure of presynaptic inhibition associated with spasticity is a gradual process. A hypothesis to explain these findings is proposed.
对正常受试者、脊髓休克患者和已发生脊髓痉挛的患者的三条节段性通路的活动进行了比较。使用跟腱反射（ATR）来评估Ia单突触通路的传导。有证据表明，振动主要通过多突触通路激活运动神经元。使用强直性振动反射（TVR）来评估该Ia多突触通路的传导。这些通路能够激活的运动神经元池的百分比（M反应）被用作传导的指标。H反射（振动）/H反射（对照）比值被用作对Ia单突触通路突触前抑制程度的评估。研究结果得出以下结论。（1）在脊髓休克时，突触前抑制大于正常，Ia单突触通路的传导减少，而Ia多突触通路的传导几乎消失。（2）在已发生的痉挛中，突触前抑制受损，Ia单突触通路的传导增加，但Ia多突触通路的传导从未恢复。（3）与痉挛相关的突触前抑制失败是一个渐进的过程。提出了一个解释这些发现的假说。
