Permanent reorganization of Ia afferent synapses on motoneurons after peripheral nerve injuries.
Permanent reorganization of Ia afferent synapses on motoneurons after peripheral nerve injuries.
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DOI：
10.1111/j.1749-6632.2010.05459.x
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发表时间：
2010-06
影响因子：
5.2
通讯作者：
Cope TC
中科院分区：
文献类型：
--
作者：
Alvarez FJ;Bullinger KL;Titus HE;Nardelli P;Cope TC
在运动神经的外周神经损伤后，运动神经元和本体感受器的轴突与外周断开，并且来自I组传入神经和运动神经元的单突触连接在脊髓中减少。在外周成功的神经再支配后，运动神经元的运动强度、本体感觉编码和Ia传入突触传递部分恢复。然而，肌肉拉伸反射永远不会恢复，运动行为仍然不协调。在这篇综述中，我们总结了最近的研究结果表明，挥之不去的运动功能障碍可能与Ia传入神经中枢连接性降低有关。首先，感觉传入突触从第九层缩回，导致输入永久性地重新定位到更远的位置，并与运动神经元显著断开。第二，本体感觉传入和肌梭之间的外周重连是不完善的。因此，一部分与运动神经元保持中枢连接的感觉传入神经可能无法在外周适当地重新连接。提出了一个假设的模型，在该模型中，外周和中枢重连缺陷的综合作用可能会解释肌肉拉伸的失败，启动或调制许多homebrag运动神经元的发射。
After peripheral nerve injuries to a motor nerve the axons of motoneurons and proprioceptors are disconnected from the periphery and monosynaptic connections from group I afferents and motoneurons become diminished in the spinal cord. Following successful reinnervation in the periphery, motor strength, proprioceptive sensory encoding, and Ia afferent synaptic transmission on motoneurons partially recover. Muscle stretch reflexes, however, never recover and motor behaviors remain uncoordinated. In this review, we summarize recent findings that suggest that lingering motor dysfunction might be in part related to decreased connectivity of Ia afferents centrally. First, sensory afferent synapses retract from lamina IX causing a permanent relocation of the inputs to more distal locations and significant disconnection from motoneurons. Second, peripheral reconnection between proprioceptive afferents and muscle spindles is imperfect. As a result, a proportion of sensory afferents that retain central connections with motoneurons might not reconnect appropriately in the periphery. A hypothetical model is proposed in which the combined effect of peripheral and central reconnection deficits might explain the failure of muscle stretch to initiate or modulate firing of many homonymous motoneurons.
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影响因子：
5.3
作者：
de Carrizosa, Maria A. Davis-Lopez;Morado-Diaz, Camilo J.;Pastor, Angel M.
通讯作者：
Pastor, Angel M.
影响因子：
2.5
作者：
Alvarez, FJ;Villalba, RM;Schneider, SP
通讯作者：
Schneider, SP
影响因子：
5.5
作者：
COPE, TC;FETZ, EE;MATSUMURA, M
通讯作者：
MATSUMURA, M
DOI：
10.1007/bf00325030
发表时间：
1968-01-01
期刊：
ZEITSCHRIFT FUR ZELLFORSCHUNG UND MIKROSKOPISCHE ANATOMIE
影响因子：
--
作者：
BLINZING.K;KREUTZBE.G
通讯作者：
KREUTZBE.G
影响因子：
2.5
作者：
Abelew, TA;Miller, MD;Nichols, TR
通讯作者：
Nichols, TR