Neuromechanical Modeling of Postural Responses

描述（由申请人提供）：由于失去平衡而导致的福尔斯跌倒是老年人受伤和死亡的主要原因，是一种广泛的神经、肌肉骨骼和认知缺陷的衰弱症状。然而，由于许多神经和肌肉骨骼因素可能导致平衡障碍-或相当于补偿策略-临床医生通常难以评估平衡障碍的严重程度，或确定其根本原因。本研究的目的是了解在站立平衡控制过程中，前馈和反馈神经机械元件对姿势稳定性的调节原理。我们选择研究神经系统在一次数据收集的时间范围内可以快速调制或选择的神经力学元素。我们定义前馈神经力学元素是那些调整内在的机械稳定性的肌肉骨骼系统在预期的姿势扰动，如姿势配置和姿势肌张力。我们定义反馈神经机械元素是那些激活肌肉反应性的姿势扰动，包括任务级反馈增益，肌肉协同作用，和脊髓反射。我们假设前馈和反馈神经机械元件被调制，以实现隐含的性能目标，如稳定性，可操作性，能量最小化，或鲁棒性的不确定性。不同的表现目标可以解释在不同试验、不同个体、不同背景或不同运动缺陷中观察到的运动变化。我们预测，神经机械元素的各种组合可能会产生定性相似的运动，但定量不同的功能和能量的后果。我们将研究目标1中正常猫和神经功能受损猫的站立平衡控制的前馈和反馈神经机械元件之间的相互作用;目标3中完整动物的短期和长期姿势适应期间。在目标2中，我们将使用姿势控制的神经力学模型来确定功能和能量成本与可能驱动健康和疾病中的姿势适应的约束之间的权衡。这项建议继续我们的一般科学框架的发展，以实现我们的长期目标，即理解，诊断和预测平衡缺陷和运动障碍的个体的最佳运动功能。 公共卫生相关性：由于失去平衡而导致的福尔斯跌倒是导致老年人死亡的主要原因。由于一些神经和肌肉骨骼缺陷，导致某人跌倒的平衡丧失可能会发生。我们将确定特定的神经损伤如何改变平衡控制的微妙但可测量的变化。我们还开发了计算机模拟和分析工具，最终可能帮助医生预测如何最好地治疗平衡障碍。

DESCRIPTION (provided by applicant): Falls due to a loss of balance are a primary cause of injury and death in the elderly, and a debilitating symptom of a wide range of neurological, musculoskeletal, and cognitive deficits. However, because many neural and musculoskeletal elements can contribute to balance impairments - or equivalently to compensatory strategies - it is often difficult for clinicians to evaluate the severity of balance impairments, or to identify their underlying causes. The objective of this project is to understand the principles governing the modulation of feedforward and feedback neuromechanical elements contributing to postural stability during standing balance control. We have chosen to study the neuromechanical elements that can be rapidly modulated or selected by the nervous system, within the time frame of one session of data collection. We define feedforward neuromechanical elements to be those that adjust the intrinsic mechanical stability of the musculoskeletal system in anticipation of a postural perturbation, such as postural configuration and postural muscle tone. We define feedback neuromechanical elements to be those that activate muscles reactively following postural perturbations, and include task-level feedback gains, muscle synergies, and spinal reflexes. We hypothesize that the feedforward and feedback neuromechanical elements are modulated to achieve implicit performance goals such as stability, maneuverability, energy minimization, or robustness to uncertainty. Differing performance goals could explain variations in movement observed across trials, across individuals, across contexts, or across motor deficits. We predict that various combinations of neuromechanical elements may produce qualitatively similar movements, and yet quantitatively different functional and energetic consequences. We will study interactions between feedforward and feedback neuromechanical elements for standing balance control in normal and neurologically-impaired cats in Aim 1; during short- and long- term postural adaptations in intact animals in Aim 3. In Aim 2, we will identify tradeoffs between functional and energetic costs and constraints that may drive postural adaptations in both health and disease using neuromechanical models of postural control. This proposal continues our development of a general scientific framework toward our long-term goal of understanding, diagnosing, and predicting optimal motor function in individuals with balance deficits, and motor impairments in general. PUBLIC HEALTH RELEVANCE: Falls due to a loss of balance are the leading cause of injury leading to death in older adults. Loss of balance causing someone to fall can happen due to a number of neurological and musculoskeletal deficits. We will identify how specific neurological impairments alter subtle, but measurable changes in balance control. We also develop computer simulation and analysis tools that may eventually help physicians predict how best to treat balance impairments.