Spinal cord maps of spatiotemporal alpha-motoneuron activation in humans walking at different speeds
Spinal cord maps of spatiotemporal alpha-motoneuron activation in humans walking at different speeds
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DOI：
10.1152/jn.00767.2005
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发表时间：
2006-02-01
影响因子：
2.5
通讯作者：
Lacquaniti, F
中科院分区：
文献类型：
--
作者：
Ivanenko, YP;Poppele, RE;Lacquaniti, F
人类以不同速度行走时的时空运动神经元激活的脊髓图。中国生物医学工程学报（英文版）39(5):559 - 561。2005年11月9日首次出版；doi: 10.1152 /约。00767.2005. 人类脊髓运动神经元活动的功能性磁共振成像（fMRI）成像仍处于起步阶段，它将仍然难以应用于行走。在这里，我们提出了一种可行的替代方法，用于记录行走过程中人类脊髓中α -运动神经元（MN）活动的时空图，类似于最近报道的猫的方法。我们记录了13名健康受试者在跑步机上以不同速度（1-7 km/h）行走时16 - 32个同侧肢体和躯干肌肉的肌电图活动，并将记录的模式映射到脊髓运动神经元池的大致背侧位置。这种方法可以在运动过程中以节段控制的方式而不是以个体肌肉控制的方式提供模式生成器输出的信息。我们发现的一个显著特征是，几乎每个脊髓节段在步进周期中都经历了至少两个激活周期，从而支持了半中心振荡器在任何节段水平上控制MN激活的观点。所得的时空地图模式在研究的步行速度范围内似乎高度刻板化，尽管也有一些系统的MN活动随速度的重新分布。MN活动的爆发要么在时间上跨越几个脊柱节段，要么在不同节段之间切换。例如，腰骶段MN活动的质量中心通常在每一步的两个周期中从吻侧位置转移到尾侧位置，显示出四个主要的激活灶：两个在上腰椎节段，两个在骶节段。结果与至少两个或更多的模式发生器的存在相一致，这些模式发生器控制着腰骶神经网络的激活。
Spinal cord maps of spatiotemporal alpha-motoneuron activation in humans walking at different speeds. J Neurophysiol 95: 602-618, 2006. First published November 9, 2005; doi: 10.1152/jn. 00767.2005. Functional MRI (fMRI) imaging of motoneuron activity in the human spinal cord is still in its infancy, and it will remain difficult to apply to walking. Here we present a viable alternative for documenting the spatiotemporal maps of alpha-motorneuron (MN) activity in the human spinal cord during walking, similar to the method recently reported for the cat. We recorded EMG activity from 16 to 32 ipsilateral limb and trunk muscles in 13 healthy subjects walking on a treadmill at different speeds (1-7 km/h) and mapped the recorded patterns onto the spinal cord in approximate rostrocaudal locations of the motoneuron pools. This approach can provide information about pattern generator output during locomotion in terms of segmental control rather than in terms of individual muscle control. A striking feature we found is that nearly every spinal segment undergoes at least two cycles of activation in the step cycle, thus supporting the idea of half-center oscillators controlling MN activation at any segmental level. The resulting spatiotemporal map patterns seem highly stereotyped over the range of walking speeds studied, although there were also some systematic redistributions of MN activity with speed. Bursts of MN activity were either temporally aligned across several spinal segments or switched between different segments. For example, the center of mass of MN activity in the lumbosacral levels generally shifted from rostral to caudal positions in two cycles for each step, revealing four major activation foci: two in the upper lumbar segments and two in the sacral segments. The results are consistent with the presence of at least two and possibly more pattern generators controlling the activation of lumbosacral MNs.