Central and peripheral mechanisms contributing to human balance control

我们都看到了恐惧、焦虑和自信对控制平衡能力的影响。试想一下，有人想要走过平衡木。如果梁是在地面上，大多数人通常没有困难走过去；然而，如果它被高高举起，人们很可能失去平衡而摔倒。有趣的是，在这两种情况下，唯一发生变化的是摔倒的威胁或后果。我们认为，对摔倒威胁的情绪反应可能是导致老年人和有平衡障碍的人出现平衡问题和摔倒的一个因素。我们的研究表明，在健康的个体中，威胁和兴奋的增加会直接影响他们控制平衡的方式。然而，威胁影响大脑控制平衡能力的具体方式目前尚不清楚。因此，研究计划的短期目标是了解威胁如何影响动态平衡反应，并可能影响大脑接收和处理与控制平衡相关的感觉信息的方式。这项研究是我了解大脑、感觉系统和肌肉如何促进健康和病理平衡的长期目标的一部分。我们将通过让受试者站在可以上升到不同高度的物理或虚拟（使用3D虚拟现实）平台上执行平衡任务来操纵威胁。将进行一系列的研究，以评估威胁如何影响我们对意外平衡干扰的反应能力，并发现威胁如何影响负责检测身体和头部运动的感觉系统。平衡性能将从地面反作用力、运动分析和在安静站立和平衡扰动时记录的肌肉活动来评估。从拟议的研究项目中获得的知识将用于确定与人类平衡控制的威胁相关的变化有关的特定神经机制，并将提高我们对情感和平衡之间的联系如何导致平衡缺陷和跌倒的理解。

We have all seen the effect that fear, anxiety and confidence can have on the ability to control balance. Just think of someone trying to walk across a balance beam. If the beam is on the ground, most people usually have no difficulty to walk across it; however, if it is raised high in the air, people are likely to lose their balance and fall. Interestingly, the only thing that has changed in those two conditions is the threat or consequence of a fall. The emotional response to the threat of falling is one factor that we believe may contribute to balance problems and falls in older adults and people with balance disorders. Our research has shown that increased threat and arousal in otherwise healthy individuals can directly influence the way they control balance. However, the specific way in which threat influences the brain's ability to control balance is currently unknown. Therefore, the short term goal of the research program is to understand how threat influences dynamic balance responses, and may influence the way the brain receives and processes sensory information relevant to controlling balance. This research is part of my long term goal to understand how the brain, sensory systems and muscles contribute to healthy and pathological balance. We will manipulate threat by having subjects perform balance tasks while standing on a physical, or virtual (using 3D virtual reality), platform that can be raised to different heights. A series of studies will be performed to assess how threat influences our ability to respond to unexpected balance disturbances and discover how threat influences sensory systems responsible for detecting movement of the body and head. Balance performance will be assessed from ground-reaction forces, motion analysis and muscular activity recorded during quiet standing and balance perturbations. Knowledge developed from the proposed research program will be used to identify the specific neural mechanisms that are involved in threat-related changes in human balance control and will improve our understanding of how links between emotion and balance may contribute to balance deficits and falls.