Spatiotemporal organization of α-motoneuron activity in the human spinal cord during different gaits and gait transitions
Spatiotemporal organization of α-motoneuron activity in the human spinal cord during different gaits and gait transitions
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DOI：
10.1111/j.1460-9568.2008.06289.x
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发表时间：
2008-06-01
影响因子：
3.4
通讯作者：
Lacquaniti, F.
中科院分区：
文献类型：
--
作者：
Ivanenko, Y. P.;Cappellini, G.;Lacquaniti, F.
在这里，我们研究了运动神经元（MN）的活动在不同的人类步态的时空组织。我们记录了32例正常人在跑台上（3-12 km/h）跑步和步行时同侧肢体和躯干肌肉的肌电活动模式。此外，我们记录了向后行走和跳跃，这是一种独特的人类步态，包括行走和跑步的特征。我们将记录的EMG活动模式映射到MN池的近似吻尾位置的脊髓上。MNs的激活呈爆发性，并以步态特异性方式被脊髓节段分离。特别是，骶骨和颈椎的激活时间明显依赖于步态。摆动相关的活动构成了腿部肌肉总MN活动的一个可观的分数（> 30%）。以非首选速度（分别以5公里/小时和9公里/小时的速度跑步和步行）行走与首选速度相比有明显差异。低速跑步的特征是骶骨激活范围更广。在高非首选的速度行走伴随着一个“非典型”的激活位点在上腰脊髓后期的立场和腰骶段的激活急剧增加。后者的研究结果表明，步态过渡的最佳速度可能与总MN活动的最佳强度有关，除了先前描述的其他因素。结果总体上支持的想法的灵活性和适应性的时空活动的脊髓回路的时间功能连接的假设的脉动爆发发生器的约束。
Here we studied the spatiotemporal organization of motoneuron (MN) activity during different human gaits. We recorded the electromyographic (EMG) activity patterns in 32 ipsilateral limb and trunk muscles from normal subjects while running and walking on a treadmill (3-12 km/h). In addition, we recorded backward walking and skipping, a distinct human gait that comprises the features of both walking and running. We mapped the recorded EMG activity patterns onto the spinal cord in approximate rostrocaudal locations of the MN pools. The activation of MNs tends to occur in bursts and be segregated by spinal segment in a gait-specific manner. In particular, sacral and cervical activation timings were clearly gait-dependent. Swing-related activity constituted an appreciable fraction (> 30%) of the total MN activity of leg muscles. Locomoting at non-preferred speeds (running and walking at 5 and 9 km/h, respectively) showed clear differences relative to preferred speeds. Running at low speeds was characterized by wider sacral activation. Walking at high non-preferred speeds was accompanied by an 'atypical' locus of activation in the upper lumbar spinal cord during late stance and by a drastically increased activation of lumbosacral segments. The latter findings suggest that the optimal speed of gait transitions may be related to an optimal intensity of the total MN activity, in addition to other factors previously described. The results overall support the idea of flexibility and adaptability of spatiotemporal activity in the spinal circuitry with constraints on the temporal functional connectivity of hypothetical pulsatile burst generators.