Discharge rates and discharge variability of muscle spindle afferents in human chronic spinal cord injury
Discharge rates and discharge variability of muscle spindle afferents in human chronic spinal cord injury
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DOI：
10.1016/j.clinph.2012.05.015
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发表时间：
2013-01-01
影响因子：
4.7
通讯作者：
Macefield, Vaughan G.
中科院分区：
文献类型：
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作者：
Macefield, Vaughan G.
目的：检验人体肌梭的放电频率和放电变异性不受脊髓损伤影响的假设。方法：将钨微电极插入 6 名脊髓损伤后下肢完全瘫痪的个体的腓神经肌束中：12 个传入神经在休息时自发活动，7 个传入神经在被动肌肉拉伸过程中被募集。为了进行比较，我们对 12 名完整受试者的 17 个自发活动传入神经和 9 个牵张募集传入神经进行了记录。结果：脊髓 (9.8 +/- 1.6 Hz) 和完整受试者 (10.2 +/- 1.3 Hz) 受试者之间自发活动肌梭的放电率没有显着差异；对于拉伸招募的传入神经来说也是如此 - 在斜坡和保持拉伸的最后 1 秒内测量的静态放电率在脊柱组和完整组之间没有差异（13.1 +/- 3.1% vs 10.0 +/- 2.5 Hz）。脊柱和完整受试者之间的放电变异性也没有差异，无论是自发活动纺锤体（8.1 +/- 2.0% vs 5.7 +/- 0.9%）还是拉伸激活纺锤体，在静态拉伸的最后 1 秒内计算（19.7 +/- 5.6% vs 17.0 +/- 1.9%）。此外，实验者对手动施加的拉伸的反应没有提供证据表明患者对拉伸的动态反应有所增加。结论：人类肌梭的静态拉伸敏感性不受慢性脊髓损伤的影响，这表明慢性脊髓损伤中静态（可能是动态）梭动驱动对瘫痪肌肉没有差异。意义：这项研究没有提供证据表明梭动驱动的增加是与慢性脊髓损伤相关的痉挛的机制，尽管进一步的研究使用在得出这些患者的动态梭运动驱动是“正常”的结论之前，需要进行受控的拉伸。 (C) 2012 年国际临床神经生理学联合会。由爱思唯尔爱尔兰有限公司出版。保留所有权利。
Objectives: To test the hypothesis that the firing rates and discharge variability of human muscle spindles are not affected by spinal cord injury.Methods: Tungsten microelectrodes were inserted into muscle fascicles of the peroneal nerve in six individuals with complete paralysis of the lower limbs following spinal cord injury: 12 afferents were spontaneously active at rest and 7 were recruited during passive muscle stretch. For comparison, recordings were made from 17 spontaneously active and 9 stretch-recruited afferents in 12 intact subjects.Results: Firing rates for the spontaneously active muscle spindles were not significantly different between the spinal (9.8 +/- 1.6 Hz) and intact (10.2 +/- 1.3 Hz) subjects; the same was true for the stretch-recruited afferents - static firing rates, measured over the final 1 s of a ramp-and-hold stretch, were not different between the spinal and intact groups (13.1 +/- 3.1% vs 10.0 +/- 2.5 Hz). There were also no differences in discharge variability between the spinal and intact subjects, either for the spontaneously active spindles (8.1 +/- 2.0% vs 5.7 +/- 0.9%) or for the stretch-activated spindles, calculated over the final 1 s of static stretch (19.7 +/- 5.6% vs 17.0 +/- 1.9%). In addition, the responses to stretch imposed manually by the experimenter provided no evidence for an increase in the dynamic response to stretch in the patients.Conclusions: The static stretch sensitivity of human muscle spindles is not affected by chronic spinal cord injury, suggesting that there is no difference in static (and possibly dynamic) fusimotor drive to paralyzed muscles in chronic spinal cord injury.Significance: This study provides no evidence for an increase in fusimotor drive as a mechanism for the spasticity associated with chronic spinal injury, though further studies using controlled stretch would be required before it can be concluded that dynamic fusimotor drive is " normal" in these patients. (C) 2012 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.