Absence of local sign withdrawal in chronic human spinal cord injury.
Absence of local sign withdrawal in chronic human spinal cord injury.
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慢性人类脊髓损伤中不存在局部征象撤回。
DOI：
10.1152/jn.00924.2002
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发表时间：
2003
期刊：
影响因子：
--
通讯作者：
Benz,ElaN
中科院分区：
文献类型：
--
作者：
Schmit,BrianD;Hornby,TGeorge;Tysseling-Mattiace,VickiM;Benz,ElaN
局部体征退缩，一种引导肢体远离有害皮肤刺激的反射，被认为是脊髓模块化组织的指示。为了评估这种组织的脊髓在慢性人类脊髓损伤（SCI）的完整性，我们测试了肌电图（EMG）和关节扭矩反应皮肤刺激施加到6个位置的腿在10个SCI志愿者和3个脊髓完整的控制。这6个位置包括足内侧弓、第二跖骨、足背、外踝腓肠神经上方区域以及小腿前后。虽然脊柱完整的受试者表现出当地的迹象撤回，从SCI受试者的数据表明，一个不变的屈曲反应模式产生的刺激位置无关。所有受试者在所有位置均产生踝关节背屈和髋关节屈曲，6个测试位置的髋关节：踝关节扭矩比无差异。一个windup交叉测试，采用一个序列的6刺激在1秒的时间间隔被用来评估是否共同的神经元通路负责模块化组织的损失。另外10名SCI志愿者使用刺激进行测试，其中刺激位置在测试序列的第2和第3刺激之间切换。对交叉刺激的反应更接近于对第三刺激的反应，而不是没有条件刺激的反应。这些结果表明，在一个刺激位点上由windup产生的增加的兴奋性在第二个位点上得以维持。这一观察结果表明，深背角神经元，通常与肌肉定位映射，可能在慢性脊髓损伤重组。
Local sign withdrawal, a reflex to direct the limb away from noxious cutaneous stimuli, is thought to be indicative of a modular organization of the spinal cord. To assess the integrity of such an organization of the spinal cord in chronic human spinal cord injury (SCI), we tested the electromyogram (EMG) and joint torque responses to cutaneous stimuli applied to 6 locations of the leg in 10 SCI volunteers and 3 spinal-intact controls. The 6 locations included the medial arch of the foot, the second metatarsal, the dorsum, the region over the sural nerve at the lateral malleolus, and the anterior and posterior aspects of the lower leg. Although spinal-intact subjects demonstrated local sign withdrawal, the data from SCI subjects indicated that an invariant flexion response pattern was produced regardless of stimulus location. Ankle dorsiflexion and hip flexion were produced in all subjects at all locations and no difference in the ratio of hip:ankle torques could be detected for the 6 test locations. A windup-crossover test, employing a sequence of 6 stimuli at 1-s intervals was used to assess whether common neuronal pathways were responsible for the loss of modular organization. An additional 10 SCI volunteers were tested using stimuli in which the stimulus location was switched between the 2nd and 3rd stimulus of the test sequence. The response to the crossover stimulus more closely resembled the response to the 3rd stimulus of a windup sequence than a response without conditioning stimuli. These results indicate that increased excitability produced by windup at one stimulus site is maintained at the 2nd site. This observation suggests that deep dorsal horn neurons, typically associated with musculotopic mapping, may be reorganized in chronic spinal cord injury.