Prolonged time course of population excitatory postsynaptic potentials in motoneurons of chronic stroke survivors.
Prolonged time course of population excitatory postsynaptic potentials in motoneurons of chronic stroke survivors.
复制标题
慢性中风幸存者运动神经元群体兴奋性突触后电位的延长时间过程。
DOI：
10.1152/jn.00288.2018
复制
发表时间：
2019
影响因子：
2.5
通讯作者：
Rymer,WilliamZ
中科院分区：
文献类型：
--
作者：
Son,Jongsang;Hu,Xiaogang;Suresh,NinaL;Rymer,WilliamZ
脊髓运动神经元的过度兴奋可能导致半球卒中后肌张力增高。这种过度兴奋的起源尚不清楚，但我们假设痉挛性运动神经元的Ia兴奋性突触后电位（EPSP）的延长可能是一种潜在的机制，通过使Ia EPSP更有效的时间总和，使动作电位启动更容易。因此，本研究的目的是量化慢性卒中幸存者脊髓运动神经元中假定的EPSP的时间过程。为了估计EPSP的时间过程，一对低强度的电刺激被依次传递到正中神经在7个半球中风幸存者和6个完整的个人，诱导从桡侧腕屈肌的H反射反应。H反射反应概率，然后被用来量化的时间过程中的运动神经元池的基础EPSP。然后，基于在对第一条件刺激没有反射反应的情况下从第二测试刺激唤起H反射的概率，推导出群体EPSP估计。我们的实验结果表明，在7个半球中风的幸存者中，6个人口的EPSP衰减的明显速度是明显较慢的痉挛相比，对侧（中风）和完整的运动神经元池。中风幸存者对侧和对照受试者肌肉之间的EPSP时程无显著差异。我们认为慢性卒中幸存者痉挛性运动神经元过度兴奋的一个潜在机制可能与Ia EPSP时程的延长有关。我们的阈下双刺激方法可以提供一种非侵入性的工具，用于量化健康和病理条件下EPSP的时间过程。新&值得注意的是，与对侧和完整的运动神经元相比，中风幸存者的痉挛运动神经元显示出延长的Ia兴奋性突触后电位（EPSP）时间过程，提示慢性卒中幸存者痉挛性运动神经元过度兴奋的一个潜在机制可能与Ia EPSP时间的延长有关当然了
Hyperexcitability of spinal motoneurons may contribute to muscular hypertonia after hemispheric stroke. The origins of this hyperexcitability are not clear, but we hypothesized that prolongation of the Ia excitatory postsynaptic potential (EPSP) in spastic motoneurons may be one potential mechanism, by enabling more effective temporal summation of Ia EPSPs, making action potential initiation easier. Thus, the purpose of this study is to quantify the time course of putative EPSPs in spinal motoneurons of chronic stroke survivors. To estimate the EPSP time course, a pair of low-intensity electrical stimuli was delivered sequentially to the median nerve in seven hemispheric stroke survivors and in six intact individuals, to induce an H-reflex response from the flexor carpi radialis muscle. H-reflex response probability was then used to quantify the time course of the underlying EPSPs in the motoneuron pool. A population EPSP estimate was then derived, based on the probability of evoking an H-reflex from the second test stimulus in the absence of a reflex response to the first conditioning stimulus. Our experimental results showed that in six of seven hemispheric stroke survivors, the apparent rate of decay of the population EPSP was markedly slower in spastic compared with contralateral (stroke) and intact motoneuron pools. There was no significant difference in EPSP time course between the contralateral side of stroke survivors and control subject muscles. We propose that one potential mechanism for hyperexcitability of spastic motoneurons in chronic stroke survivors may be associated with this prolongation of the Ia EPSP time course. Our subthreshold double-stimulation approach could provide a noninvasive tool for quantifying the time course of EPSPs in both healthy and pathological conditions.NEW & NOTEWORTHYSpastic motoneurons in stroke survivors showed a prolonged Ia excitatory postsynaptic potential (EPSP) time course compared with contralateral and intact motoneurons, suggesting that one potential mechanism for hyperexcitability of spastic motoneurons in chronic stroke survivors may be associated with this prolongation of the Ia EPSP time course.