Sensorimotor Integration in Human Postural Control

描述(由申请人提供)：t 该项目的长期目标是了解感觉运动整合如何有助于人体姿势稳定。要完全理解姿势控制，需要了解中枢神经系统(CNS)如何整合来自多个感官来源的身体定向信息，以响应环境条件的变化而产生适当的平衡校正，以及生物力学如何影响感觉信息的使用来进行姿势控制。这一建议的中心假设是，在改变可用感觉定向信息的环境中，以及在生物力学因素限制身体运动和改变稳定性极限的条件下，中枢神经系统积极调节感觉整合，以实现最佳的动态平衡控制。 拟议的工作有三个具体目标。第一个目标是确定被动的、生物力学相关的和主动的、神经介导的对在矢状面上平衡控制所需的平衡校正的产生的贡献。被动和主动机制将根据身体摇摆反应的时间来区分，这些反应是由持续的扰动引起的，以达到平衡。姿势控制系统也将受到挑战，人为地推迟感觉定向信息的到达，以确定受试者如何补偿延迟的感觉反馈。第二个目标是确定姿势控制系统整合多源感觉定向信息的能力。假设感觉整合是通过感觉线索的加权组合实现的，加权因子随着环境和生物力学条件的变化而变化，加权因子的选择由最优控制策略决定。第三个目的是描述用于控制前额平面身体摇摆的感觉-运动整合策略，并确定由于站姿宽度变化而产生的生物力学约束如何影响感觉-运动整合过程。 这项拟议的研究依赖于一种基于模型的方法来解释和预测各种环境和实验条件下的姿势行为。在工程学科中开发的用于系统识别的方法将被广泛使用。 涉及感觉运动整合主动调节的异常可能是不稳定和跌倒的一个未被认识的来源。更好地了解这些积极的调节过程可能会导致新的康复方法和新的临床平衡功能测试。

DESCRIPTION (provided by applicant): T The long-term objective of this project is to understand how sensorimotor integration contributes to postural stability in humans. A complete understanding of postural control requires knowledge of how the central nervous system (CNS) integrates body-orientation information from multiple sensory sources to generate appropriate balance corrections in response to changing environmental conditions and how biomechanics influence the use of sensory information for postural control. The central hypothesis of this proposal is that the CNS actively regulates sensory integration to achieve optimal dynamic control of balance in environments that alter the available sensory-orientation information and in conditions where biomechanical factors constrain body motion and alter stability limits. The proposed work has three specific aims. The first aim is to identify the passive, biomechanically related and active, neurally-mediated contributions to the generation of balance corrections required for balance control in the sagittal plane. Passive and active mechanisms will be distinguished from one another based on the timing of body-sway responses evoked by continuous perturbations to balance. The postural control system will also be challenged by artificially delaying the arrival of sensory-orientation information to determine how subjects compensate for delayed sensory feedback. The second aim is to determine the ability of the postural control system to integrate multiple sources of sensory-orientation information. The hypothesis is that sensory integration is achieved by a weighted combination of sensory cues, the weighting factors change as a function of environmental and biomechanical conditions, and the selection of weighting factors is determined by an optimal-control strategy. The third aim is to characterize the sensorimotor integration strategies used for the control of body sway in the frontal plane and to determine how biomechanical constraints due to changes in stance width influence the sensorimotor-integration process. The proposed research relies on a model-based approach to explain and to predict postural behavior in a variety of environments and experimental conditions. Methodology developed in engineering disciplines for system identification will be used extensively. Abnormalities involving the active regulation of sensorimotor integration may be an unrecognized source of instability and falls. A better understanding of these active regulatory processes may lead to new rehabilitative methods and new clinical balance-function tests.