Locomotion Control by Lumbar Spinal Cord Stimulation

描述（由申请人提供）：在腰段以上的脊髓损伤（SCI）后，由于失去来自大脑的下行命令，下肢将瘫痪。然而，脊髓损伤后，腰段脊髓的神经元间网络仍然可以维持运动功能，如空气步。慢性SCI猫也可以在训练后在跑步机上站立或行走一小段时间。不完全性脊髓损伤的患者经过大量的踏车训练后可以恢复地面活动能力。这些结果表明，脊髓损伤后，腰段脊髓神经元间网络在适当激活的情况下可以进行运动。因此，我们建议在这个项目中，电激活猫的腰椎神经元间运动网络，以恢复SCI后的行走功能。先前的研究表明，腰椎神经元间运动网络可以被激活，只有几个电极，以引起复杂的，协调的，多关节的运动。当使用传统的外周神经肌肉刺激时，这样的运动需要许多电极：脊髓刺激的其他优点包括：（1）。椎管内的电极经历相对小的运动，因此比肌内电极表现出更少的断裂;（2）.腰部神经元间运动网络可以以生理学募集顺序激活肌肉，这更能抵抗疲劳。肌肉疲劳是周围神经肌肉刺激中的主要问题。在这个项目中，我们将确定有效的刺激位置，并制定控制策略，以恢复行走功能的SCI猫，使用脊髓外电刺激的腰脊髓结合脊髓内刺激。脊髓外电极比脊髓内电极对脊髓的侵入性更小，但是脊髓内电极比脊髓外电极更有效地激活腰脊髓深处的神经成分。这项研究在猫身上的成功将提示如何进行人类研究。该项目的长期目标是开发一种基于腰椎脊髓刺激的新型运动神经假体。这些研究不仅有助于提高我们对腰髓运动控制的认识，而且对脊髓损伤患者也有一定的帮助。

DESCRIPTION (provided by applicant): After spinal cord injury (SCI) above the lumbar level, the lower limbs will be paralyzed due to the loss of descending commands from the brain. However, after SCI the interneuronal network in lumbar spinal cord can still sustain locomotor function such as air-stepping. Chronic SCI cats can also stand or walk for a short time on a treadmill after training. Patients with incomplete SCI can regain over ground mobility after extensive treadmill training. All of these observations indicate that the interneuronal network in lumbar spinal cord can carry out locomotion after SCI, if it can be activated properly. Therefore, we propose in this project to electrically activate the lumbar interneuronal locomotor network in cats to restore walking function after SCI. Previous studies have shown that the lumbar interneuronal locomotor network can be activated with only a few electrodes to elicit complex, coordinated, multi-joint movements. Such movements require many electrodes when traditional peripheral neuromuscular stimulation is used: Other advantages of spinal cord stimulation include: (1). electrodes in spinal canal experience relatively small movements, and thus exhibit less breakage, than the intramuscular electrodes; (2). the lumbar interneuronal locomotor network can activate muscles in a physiological recruitment order, which is more resistant to fatigue. Muscle fatigue is a major problem in the peripheral neuromuscular stimulation. In this project we will identify the effective stimulation locations and develop the control strategy to restore walking function in SCI cats, using extra- spinal electrical stimulation of the lumbar spinal cord in combination with intra-spinal stimulation. The extra- spinal electrode is less invasive to the spinal cord than the intra-spinal electrode, but the intra-spinal electrode is more effective than the extra-spinal electrode to activate the neural component deep in the lumbar spinal cord. The success of this study in cat will suggest how human studies could be pursued. The long-term goal of this project is to develop a new neuroprosthesis for locomotion based on lumbar spinal cord stimulation. The proposed studies will not only improve our understanding of locomotion control in lumbar spinal cord but also benefit SCI patients.