Functional redundancy of ventral spinal locomotor pathways
Functional redundancy of ventral spinal locomotor pathways
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DOI：
10.1523/jneurosci.22-01-00315.2002
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发表时间：
2002-01-01
影响因子：
5.3
通讯作者：
Whittemore, SR
中科院分区：
文献类型：
--
作者：
Loy, DN;Magnuson, DSK;Whittemore, SR
识别负责启动自发运动的长纤维束对于脊髓损伤（SCI）修复策略至关重要。来自中脑运动区和脑桥延髓内侧网状结构负责虚构的运动在去大脑准备项目的脊髓胸腰段水平通过网状脊髓轴突的腹外侧索（VLF）的路径。然而，自发地上运动的关键白色物质区域仍然不清楚，因为猫，猴和人类显示不同程度的运动恢复后腹侧SCI。我们研究了有髓束的VLF和腹柱（VC）的成年大鼠使用脱髓鞘病变的自发地上运动的贡献。动物接受溴化乙锭加光子照射，产生足以停止VLF、VC、VLF-VC或完全腹侧白色物质（CV）中轴突传导的离散脱髓鞘病变。在损伤后1、2和4周研究行为[开放视野Basso、Beattie和Bresnahan（BBB）评分和网格行走]和经颅磁运动诱发电位（tcMMEP）。VLF病变导致tcMMEP完全丧失或严重衰减，平均BBB评分为18.0，无网格行走缺陷。VC病变产生的行为类似于VLF病变的动物，但没有显着影响tcMMEP。VC-VLF和CV病变导致tcMMEP信号完全丧失，平均BBB评分分别为12.7和6.5。我们的数据支持的腹侧白色的问题，可能包括一个系统的多个下行路径subserving自发地上运动在完整的动物轴突的弥漫性安排。
Identification of long tracts responsible for the initiation of spontaneous locomotion is critical for spinal cord injury (SCI) repair strategies. Pathways derived from the mesencephalic locomotor region and pontomedullary medial reticular formation responsible for fictive locomotion in decerebrate preparations project to the thoracolumbar levels of the spinal cord via reticulospinal axons in the ventrolateral funiculus (VLF). However, white matter regions critical for spontaneous over-ground locomotion remain unclear because cats, monkeys, and humans display varying degrees of locomotor recovery after ventral SCIs. We studied the contributions of myelinated tracts in the VLF and ventral columns (VC) to spontaneous over-ground locomotion in the adult rat using demyelinating lesions. Animals received ethidium bromide plus photon irradiation producing discrete demyelinating lesions sufficient to stop axonal conduction in the VLF, VC, VLF-VC, or complete ventral white matter (CV). Behavior [open-field Basso, Beattie, and Bresnahan (BBB) scores and grid walking] and transcranial magnetic motor-evoked potentials (tcMMEP) were studied at 1, 2, and 4 weeks after lesion. VLF lesions resulted in complete loss or severe attenuation of tcMMEPs, with mean BBB scores of 18.0, and no grid walking deficits. VC lesions produced behavior similar to VLF-lesioned animals but did not significantly affect tcMMEPs. VC-VLF and CV lesions resulted in complete loss of tcMMEP signals with mean BBB scores of 12.7 and 6.5, respectively. Our data support a diffuse arrangement of axons within the ventral white matter that may comprise a system of multiple descending pathways subserving spontaneous over-ground locomotion in the intact animal.