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

复杂的步态运动，即步态运动学，与产生这些运动的所有肌肉的本体感觉反馈有关。这种反馈是由自身产生的动作产生的，有助于运动活动，并在发出错误或偏离预期动作的信号时用于纠正动作。然而，除了自然产生的反馈之外，应用人工本体感觉信息到目前为止并没有始终如一地或很大程度上改变步态动作。在这里，我们提出复杂的本体感觉刺激，受到步态运动学的启发，以更好地模拟错误信息，可能会导致步态运动学的巨大变化。我们将使用我们实验室开发的独特的多可控震源系统，该系统可以根据步态事件产生本体感觉刺激，基于实时运动学和动力学测量。它可以激活多达12块肌肉的本体感觉，以重现与步态等复杂运动相关的感觉信息。我们将用它来产生更强烈的本体感觉活动，通常与稳定步态有关的模式，在步态中延长或缩短的肌肉，在一个关节或每个下肢关节上，或与运动学启发的模式，如滑步等大步态扰动。这些刺激将在稳态步态和由于改变分体式皮带仪表式跑步机其中一个皮带的速度而引起的不可预测的步态扰动期间应用。我们将测量和比较不同条件下的步态运动学和平衡性以及时空参数。我们假设，当刺激更全面地再现实际本体感觉模式时，我们将获得最大的步态运动学变化，即应用于多个关节的伸长肌肉，以及在适应复杂步态情况下的运动，如步态扰动。这一创新的研究计划将有助于理解本体感觉信息在塑造步态运动中的作用。从长远来看，我们将为理解本体感觉如何促进运动控制和学习做出实质性贡献。它还可能导致为不同的目的设计穿戴在身上的传感器和执行器，如增强/虚拟现实，我们可以根据虚拟场景中发生的动作随意改变动作，或者通过在线动作矫正、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.