Kinematic-specific proprioceptive stimulations to better understand sensory control of gait movements

步态的复杂运动，即步态运动学，与来自产生这些运动所涉及的所有肌肉的本体感受反馈相关联。这种反馈由自发运动产生，促进运动活动，并在它发出错误或偏离预期运动的信号时用于纠正运动。然而，除了自然发生的反馈之外，应用人工本体感受信息到目前为止并没有一致地或很大程度上改变步态运动。在这里，我们提出，复杂的本体感受刺激，步态运动学的启发，以更好地模仿错误的信息，可以引起步态运动学的大的变化。我们将使用我们实验室开发的独特的多振动器系统，该系统可以根据步态事件，基于实时运动学和动力学测量产生本体感受刺激。它可以激活多达12块肌肉的本体感受，以再现与步态等复杂运动相关的感觉信息。我们将使用它来产生更强烈的本体感受活动，其模式通常与稳态步态相关联，在步态期间延长或缩短的肌肉上，在一个关节或每个下肢关节上，或从运动学中获得灵感的模式，如滑动等大步态扰动。这些刺激将在稳态步态期间和通过改变分离式带仪表跑步机的其中一个带的速度引起的不可预测的步态扰动期间施加。我们将测量和比较步态运动学和平衡和时空参数之间的条件。我们假设，我们将获得步态运动学的最大变化，刺激更全面地再现实际的本体感受模式，即应用于多个关节的延长肌肉，以及在适应性运动过程中复杂的步态情况，如步态扰动。这项创新的研究计划将有助于了解本体感受信息在塑造步态运动中的作用。从长远来看，我们将对本体感觉如何促进运动控制和学习做出实质性贡献。它还可能导致设计用于不同目的的身体穿戴式传感器和致动器，例如增强/虚拟现实，在那里我们可以根据虚拟场景中发生的动作随意改变动作，或者通过在线运动校正，娱乐，表演艺术以及身体康复来学习新的运动技能。

Complex movements of gait, i.e. gait kinematics, are associated with proprioceptive feedback coming from all muscles involved to produce these movements. This feedback, produced by self-generated movements, facilitates motor activity and is used to correct movements when it signals an error or a departure from intended movement. However, applying an artificial proprioceptive message in addition to the naturally occurring feedback did not up-to now change gait movements consistently or largely. Here, we propose that complex proprioceptive stimulation, inspired by gait kinematics, to better mimic error messages, could induce large changes of gait kinematics. We will use a unique system of multiple vibrators, developed in our lab, that can generate proprioceptive stimulations according to gait events, based on real-time kinematics and kinetics measurements. It can activate proprioception of up to 12 muscles, to reproduce sensory messages associated with complex movements such as gait. We will use it to generate a more intense proprioceptive activity with the pattern usually associated with steady-state gait, on the muscles that are lengthened or shortened during gait, on one joint or every lower-limb joints, or with a pattern inspired from kinematics a large gait perturbations such as a slip. These stimulations will be applied during steady-state gait and during unpredictable gait perturbation induced by changing the speed of one of the belts of a split-belt instrumented treadmill. We will measure and compare gait kinematics and balance and spatiotemporal parameters between conditions. We hypothesize that we will obtain the largest change in gait kinematics with stimulations reproducing more comprehensively actual proprioceptive patterns, i.e. applied on lengthening muscles of multiple joints, and during adaptive locomotion to complex gait situations such as gait perturbations. This innovative research program will help to understand the role of proprioceptive information in shaping gait movements. In the long term, we will make substantial contributions to the understanding of how proprioception can facilitate motor control and learning. It may also lead to the design of body-worn sensors and actuators for different purposes such as augmented/virtual reality, where we could change a movement at will according to the action that happens in the virtual scene, or to learn new motor skills with online movement correction, entertainment, performing arts, as well as for physical rehabilitation.