Balgrist University Hospital, Zurich, Switzerland.
Clin Neurophysiol. 2010 Dec;121(12):2152-8. doi: 10.1016/j.clinph.2010.05.018. Epub 2010 Jun 15.
In healthy subjects, spinal reflexes (SR) evoked by non-noxious tibial nerve stimulation consist of an early (60-120ms latency) and an occasional late-appearing (120-450ms latency) component in the ipsilateral tibialis anterior. In chronic (>1year) complete spinal cord injured (cSCI) subjects early components are small or lacking while late components are dominant. Here we report on the modulation of SR by assisted locomotion in healthy and chronic motor cSCI subjects.
SR was evoked by tibial nerve stimulation at the terminal stance phase during assisted locomotion and was compared to SR recorded during upright stance.
In chronic cSCI subjects only a late SR component was consistently present during upright stance. However during assisted locomotion, an early SR component appeared, while amplitude of the late SR component became small. In contrast, in healthy subjects the early SR component dominated in all conditions, but a small late component appeared during assisted locomotion.
A more balanced activity of early and late SR components occurred in both subject groups if an appropriate proprioceptive input was provided.
Early and late SR components are assumed to reflect the activity of separate neuronal circuits, which are associated with the locomotor circuitry possibly by shaping the pattern.
在健康受试者中，由非伤害性胫神经刺激引发的脊髓反射（SR）在同侧胫骨前肌中表现为早期（60-120ms 潜伏期）和偶尔出现的晚期（120-450ms 潜伏期）成分。在慢性（>1 年）完全性脊髓损伤（cSCI）受试者中，早期成分较小或缺失，而晚期成分占主导地位。在这里，我们报告了健康和慢性运动性 cSCI 受试者在辅助运动时 SR 的调制。
在辅助运动的终末站立阶段通过胫神经刺激诱发 SR，并与直立站立时记录的 SR 进行比较。
在慢性 cSCI 受试者中，只有晚期 SR 成分在直立站立时始终存在。然而，在辅助运动期间，早期 SR 成分出现，而晚期 SR 成分的幅度变小。相比之下，在健康受试者中，所有条件下早期 SR 成分都占主导地位，但在辅助运动期间出现了一个较小的晚期成分。
如果提供适当的本体感受输入，两个受试者组的早期和晚期 SR 成分的活动更加平衡。
早期和晚期 SR 成分被认为反映了不同的神经元回路的活动，这些回路可能通过塑造模式与运动回路相关联。
