Axonal remodeling in the corticospinal tract after stroke: how does rehabilitative training modulate it?
Axonal remodeling in the corticospinal tract after stroke: how does rehabilitative training modulate it?
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DOI：
10.4103/1673-5374.200792
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发表时间：
2017-02
影响因子：
6.1
通讯作者：
Miyamoto O
中科院分区：
文献类型：
--
作者：
Okabe N;Narita K;Miyamoto O
中风会导致长期残疾，通常采用康复训练来改善连续功能恢复。脑损伤后，幸存的神经元经历形态改变以重建剩余的神经网络。在运动系统中，这种神经网络重塑被观察为运动图重组。由于其与功能恢复显着相关，运动图重组被认为是中风后功能恢复的关键现象。尽管运动图重组的机制尚不清楚，但越来越多的证据表明皮质脊髓束轴突重塑的关键作用。在这项研究中，我们回顾了先前研究中风后皮质脊髓束轴突重塑的研究，并讨论了哪些机制可能是康复训练的刺激作用的基础。根据皮质脊髓神经元的位置和原始目标，皮质脊髓束的轴突重塑可分为三种类型，并且同侧和对侧半球中所有幸存的皮质脊髓神经元似乎都可以参与轴突重塑和运动图重组。通过轴突重塑，皮质脊髓神经元将其输出选择性从单个区域改变为多个区域，以补偿丧失的功能。皮质脊髓轴突的重塑受到组织破坏程度的影响，并受到各种治疗干预措施（包括康复训练）的促进。尽管康复促进轴突重塑的精确分子机制仍然难以捉摸，但先前的数据表明康复训练通过上调促进生长和下调生长抑制信号来促进轴突重塑。
Stroke causes long-term disability, and rehabilitative training is commonly used to improve the consecutive functional recovery. Following brain damage, surviving neurons undergo morphological alterations to reconstruct the remaining neural network. In the motor system, such neural network remodeling is observed as a motor map reorganization. Because of its significant correlation with functional recovery, motor map reorganization has been regarded as a key phenomenon for functional recovery after stroke. Although the mechanism underlying motor map reorganization remains unclear, increasing evidence has shown a critical role for axonal remodeling in the corticospinal tract. In this study, we review previous studies investigating axonal remodeling in the corticospinal tract after stroke and discuss which mechanisms may underlie the stimulatory effect of rehabilitative training. Axonal remodeling in the corticospinal tract can be classified into three types based on the location and the original targets of corticospinal neurons, and it seems that all the surviving corticospinal neurons in both ipsilesional and contralesional hemisphere can participate in axonal remodeling and motor map reorganization. Through axonal remodeling, corticospinal neurons alter their output selectivity from a single to multiple areas to compensate for the lost function. The remodeling of the corticospinal axon is influenced by the extent of tissue destruction and promoted by various therapeutic interventions, including rehabilitative training. Although the precise molecular mechanism underlying rehabilitation-promoted axonal remodeling remains elusive, previous data suggest that rehabilitative training promotes axonal remodeling by upregulating growth-promoting and downregulating growth-inhibiting signals.