Sensory contributions to human movement and balance.

人类保持直立姿势的任务涉及一个复杂的控制系统，该系统必须使用和整合来自三个主要感觉来源的感觉信息：前庭系统、体感系统和视觉系统。我的基础研究项目的长期目标是更好地理解这些感官输入在控制人类站立平衡、运动和运动中所起的基本作用。为了继续这个方向的工作，将进行两个主要的集中研究领域。第一个主要集中研究领域的短期目标将集中于下行通路对人类受试者单个运动神经元调节的影响。我们实验室最近使用表面肌电图和丝肌电图进行的研究表明，前庭脊髓下行通路和网状脊髓通路与人类下肢运动神经元之间存在显著的耦合。该实验将进一步研究这些输入在非站立任务和安静站立时对运动神经元的影响。第二个主要集中领域的短期目标将是研究人体肌肉纺锤体的调节，并使用一种称为微神经摄影的研究技术。在第一组实验中，我们将观察在不同水平的肌肉激活（被动和自愿同心/偏心收缩）下，下肢肌肉纺锤波在真实的生理肌肉延长和缩短时的反应概况。在第二组实验中，不同类型的刺激，已知可以激活脑干下行通路，并与前庭系统（随机前庭刺激）和网状系统（声刺激）相关，将用于预设肌肉纺锤体。有证据表明，这些下行通路在肌肉纺锤体的伽马运动神经元调节中发挥作用。本研究提案中的实验将使我们深入了解在正常站立状态下，某些下行和外周输入如何调节肌肉纺锤体和运动单元的行为。

The task of maintaining upright stance in the human involves a complex control system that has to use and integrate sensory information from primarily three sensory sources: the vestibular system, the somatosensory system, and the visual system. The LONG TERM GOAL of my basic research program is to better understand the fundamental role played by these sensory inputs in the control of standing balance, locomotion and movement in humans. To continue with this direction of work, two main concentration areas of research will be carried out. The SHORT TERM goal of the first main concentration area of research will focus on the influence of descending pathways on the regulation of single motorneurons in human subjects. Recent research in our laboratory using surface and wire electromyography has demonstrated significant coupling between descending vestibulospinal and reticulospinal pathways onto human motorneurons in the lower limb. The proposed experiments will further investigate the influence of these inputs on motorneurons during non standing tasks and during quiet stance. The SHORT TERM goal of the second main concentration area will be to investigate the regulation of the human muscle spindle, and uses a research technique termed microneurography. In the first set of experiments, we will look at the response profile of muscle spindles of the lower limb during realistic physiological muscle lengthening and shortening during different levels of muscle activation (passive and voluntary concentric/eccentric contractions). In the second set of experiments, different types of stimuli, known to activate the descending brainstem pathways, and associated with vestibular (stochastic Vestibular stimulation) and reticular systems (acoustic stimulation), will be used to precondition the muscle spindle. Evidence suggests that these descending pathways play a role in gamma motorneuron regulation of the muscle spindle. The experiments in this grant proposal will provide us with insight into how certain descending and peripheral inputs regulate muscle spindle and motor unit behaviour during normal stance.