Restoration of movement using muscle synergies to control natural limb dynamics

描述(申请人提供)：控制每一个动作，无论是基本的反射还是复杂的技巧，都是非常复杂的，涉及到控制分布在四肢和身体各处的肌肉。这种复杂性是存在的，无论运动是由神经系统自然产生的，还是由康复工程师为恢复运动损伤后的运动而人工产生的。因此，了解用于克服这些复杂性的神经策略可以潜在地为我们在受伤后恢复运动的能力提供新的进展。我们在建议的研究中采用这种方法，试图将来自基础实验和理论研究的见解转化为改进用于恢复运动功能的策略。这项研究中进行的实验是基于最近提出的两个简化生物马达控制的原则。第一个原理表明，神经系统利用肌肉的协同作用来减少在产生动作时需要指定的变量的数量。在这个假说中，每一种协同作用都控制着一小群肌肉的激活，通过灵活地结合多种协同作用来产生复杂的运动。第二个原理认为神经系统利用肢体的内在动力来提高运动控制的效率。在这个假设中，肌肉和骨骼的特性允许某些运动指令在产生动作时特别有效。在这项建议中，我们将这两个原则结合起来，以开发一种新的损伤后运动功能恢复的策略。特别是，我们将开发和评估一种基于肌肉协同效应的控制器，该控制器旨在利用肢体的内在动力学。我们已经在仿真工作中证明了该假设能够有效地产生大范围的运动。所提出的实验将扩展这一模拟工作，并通过使用它来复活瘫痪的肢体来直接评估该策略。具体地说，这项研究将1)使用肌肉骨骼动力学的实验测量来识别大鼠后肢的低维表示，2)识别一组控制大鼠后肢内在动力学的肌肉协同效应，3)最后利用这些协同效应在瘫痪的肢体中产生动作。因此，这项研究将直接测试这种利用肌肉协同作用来开发肢体内在动力的策略是否能够恢复受伤后的运动功能。这项工作将采用最近的新理论研究，并将其转化为具有直接临床意义的实验情况。因此，这项研究的结果有可能极大地促进临床应用，使用控制策略恢复运动障碍患者的运动。 公共卫生相关性：该提案中的研究将评估一种恢复瘫痪后运动功能的新策略。这一策略将极大地简化使用功能性电刺激控制肢体运动，提高康复策略的效率和效果。因此，本研究中将要进行的实验有可能极大地促进运动障碍患者功能恢复的临床应用。

DESCRIPTION (provided by applicant): The control of every movement, whether it is a basic reflex or a sophisticated skill, is highly complex, involving the control of muscles distributed throughout the limb and body. This complexity is present whether movements are produced naturally by the nervous system or artificially by rehabilitation engineers for the restoration of movement following motor impairments. Understanding the neural strategies used to overcome these complexities can therefore potentially provide new advances in our ability to restore movement following injury. We take this approach in the proposed research, attempting to translate insights derived from basic experimental and theoretical research in order to improve strategies used to restore motor function. The experiments performed in this research are based on two recently proposed principles for the simplification of biological motor control. The first principle suggests that the nervous system uses muscle synergies to reduce the number of variables that need to be specified in the production of movements. In this hypothesis, each such 'synergy' controls the activation of a small group of muscles, with complex movements produced by flexibly combining multiple synergies. The second principle suggests that the nervous system exploits the intrinsic dynamics of the limb in order to increase the efficiency of motor control. In this hypothesis, the properties of the muscles and skeleton allow certain motor commands to be particularly effective in producing movements. In this proposal, we combine these two principles in order to develop a novel strategy for the restoration of motor function following injury. In particular, we will develop and evaluate a controller based on muscles synergies which are designed to exploit the intrinsic dynamics of the limb. We have shown in simulation work that this hypothesis is capable of producing a wide range of movement efficiently and effectively. The proposed experiments will extend this simulation work and evaluate this strategy directly by using it to reanimate a paralyzed limb. Specifically, this research will 1) use experimental measurements of the musculoskeletal dynamics to identify a low dimensional representation of the rat hindlimb, 2) identify a set of muscle synergies which controls the intrinsic dynamics of the rat hindlimb, 3) then finally use these synergies to produce movements in a paralyzed limb. This research will therefore directly test whether this strategy of using muscle synergies to exploit intrinsic limb dynamics is capable of restoring motor function following injury. This work will take recent novel theoretical research and translate it to an experimental situation with direct clinical relevance. The results of this research therefore have the potential to significantly advance clinical applications using control strategies to restore movement in patients with motor impairments. PUBLIC HEALTH RELEVANCE: The research in this proposal will evaluate a novel strategy for restoring motor function following paralysis. This strategy will greatly simplify the control of limb movements using functional electrical stimulation, increasing the efficiency and efficacy of rehabilitation strategies. The experiments to be performed in this research therefore have the potential to significantly advance clinical applications for the restoration of function in patients with motor impairments.