Seiterle Stefan, Susko Tyler, Artemiadis Panagiotis K, Riener Robert, Igo Krebs Hermano
Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave, 3-137 Cambridge, MA 02139, USA; Department of Mechanical and Process Engineering, ETH Zurich, Switzerland.
Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave, 3-137 Cambridge, MA 02139, USA.
J Biomech. 2015 Aug 20;48(11):2837-43. doi: 10.1016/j.jbiomech.2015.04.042. Epub 2015 May 8.
Locomotion involves complex neural networks responsible for automatic and volitional actions. During locomotion, motor strategies can rapidly compensate for any obstruction or perturbation that could interfere with forward progression. In this pilot study, we examined the contribution of interlimb pathways for evoking muscle activation patterns in the contralateral limb when a unilateral perturbation was applied and in the case where body weight was externally supported. In particular, the latency of neuromuscular responses was measured, while the stimulus to afferent feedback was limited. The pilot experiment was conducted with six healthy young subjects. It employed the MIT-Skywalker (beta-prototype), a novel device intended for gait therapy. Subjects were asked to walk on the split-belt treadmill, while a fast unilateral perturbation was applied mid-stance by unexpectedly lowering one side of the split-treadmill walking surfaces. Subject's weight was externally supported via the body-weight support system consisting of an underneath bicycle seat and the torso was stabilized via a loosely fitted chest harness. Both the weight support and the chest harness limited the afferent feedback. The unilateral perturbations evoked changes in the electromyographic activity of the non-perturbed contralateral leg. The latency of all muscle responses exceeded 100ms, which precludes the conjecture that spinal cord alone is responsible for the perturbation response. It suggests the role of supraspinal or midbrain level pathways at the inter-leg coordination during gait.
运动涉及负责自动和自主行动的复杂神经网络。在运动过程中，运动策略可以迅速补偿任何可能干扰向前推进的障碍物或干扰。在这项初步研究中，我们研究了在施加单侧干扰以及体重由外部支撑的情况下，肢体间通路对诱发对侧肢体肌肉激活模式的贡献。特别是，在传入反馈刺激受限的情况下，测量了神经肌肉反应的潜伏期。该初步实验对六名健康的年轻受试者进行。实验使用了麻省理工学院的“太空漫步者”（β原型），这是一种用于步态治疗的新型设备。受试者被要求在分体式跑步机上行走，在单腿支撑中期，通过意外降低分体式跑步机行走表面的一侧来施加快速的单侧干扰。受试者的体重通过由下方自行车座椅组成的体重支撑系统得到外部支撑，躯干通过宽松佩戴的胸部安全带得以稳定。体重支撑和胸部安全带都限制了传入反馈。单侧干扰引起了未受干扰的对侧腿部肌电图活动的变化。所有肌肉反应的潜伏期均超过100毫秒，这排除了仅由脊髓负责干扰反应的推测。这表明在步态期间，脊髓上或中脑水平通路在腿部间协调中发挥了作用。
