Roby-Brami A, Bussel B
Brain. 1987 Jun;110 ( Pt 3):707-25. doi: 10.1093/brain/110.3.707.
Electromyographic (EMG) flexor muscle responses evoked by electrical stimulation of ipsilateral peripheral nerves were studied in 16 patients with clinically complete spinal cord transection. Stimuli were applied either to a cutaneous nerve (sural) or to a mixed nerve (tibial) and muscle responses were recorded from tibialis anterior, biceps femoris and rectus femoris. EMG recordings after both sural and tibial nerve stimulation showed that distinct early and late ipsilateral flexor muscle responses could be elicited. This distinction was more evident for tibialis anterior. The latency of the early responses averaged approximately 100 ms with sural and 75 ms with tibial nerve stimulation. This corresponds to the latency of the flexion withdrawal reflex previously described in normal man. After sural stimulation, the early reflex appeared in biceps femoris at a threshold intensity not significantly different from that in normal man given the same stimulation parameters. Late responses appeared after a longer latency (130 ms) and at a lower threshold than the early flexor reflex. In all patients a striking feature of the late response was that its latency increased with increasing stimulus intensity, the maximum latency being as long as 450 ms. This increase also occurred with increasing duration of high intensity stimulus trains. Neither the appearance of a late response nor its latency increase could be explained by a peripheral loop due to a preceding muscle contraction (from either motor axon stimulation or motoneuronal discharge corresponding to the early flexion reflex). It was therefore concluded that both were directly elicited by the afferent volley set up by electrical stimulation. The low threshold of the late reflex corresponded to the excitation of relatively rapidly conducting afferents and its central spinal delay was more than 100 ms. The late reflexes were compared with those described by Andén et al. (1964) in the acute spinal cat injected with DOPA and were found to have similar characteristics. The mechanism for the increase in latency of the late response is discussed in relation to the interpretation of Lundberg (1979).
对16例临床诊断为完全性脊髓横断损伤的患者，研究了电刺激同侧周围神经所诱发的肌电图（EMG）屈肌反应。刺激施加于皮神经（腓肠神经）或混合神经（胫神经），并记录胫骨前肌、股二头肌和股直肌的肌肉反应。腓肠神经和胫神经刺激后的EMG记录显示，可引出明显的早期和晚期同侧屈肌反应。这种区别在胫骨前肌中更为明显。早期反应的潜伏期在腓肠神经刺激时平均约为100毫秒，在胫神经刺激时为75毫秒。这与先前在正常人中描述的屈肌退缩反射的潜伏期相对应。腓肠神经刺激后，股二头肌中早期反射出现时的阈值强度与给予相同刺激参数的正常人相比无显著差异。晚期反应出现的潜伏期较长（130毫秒），且阈值低于早期屈肌反射。在所有患者中，晚期反应的一个显著特征是其潜伏期随刺激强度的增加而增加，最大潜伏期长达450毫秒。随着高强度刺激序列持续时间的增加，这种增加也会出现。晚期反应的出现及其潜伏期增加均不能用先前肌肉收缩（来自运动轴突刺激或与早期屈肌反射相对应的运动神经元放电）所导致的外周环路来解释。因此得出结论，两者均由电刺激所引发的传入冲动直接诱发。晚期反射的低阈值对应于相对快速传导的传入神经的兴奋，其在脊髓中的中枢延迟超过100毫秒。将晚期反射与Andén等人（1964年）在注射多巴的急性脊髓猫中所描述的反射进行了比较，发现它们具有相似的特征。结合Lundberg（1979年）的解释，讨论了晚期反应潜伏期增加的机制。
