Dynamic regulation of sensorimotor integration in human postural control
Dynamic regulation of sensorimotor integration in human postural control
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DOI：
10.1152/jn.00516.2003
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发表时间：
2004-01-01
影响因子：
2.5
通讯作者：
Loughlin, PJ
中科院分区：
文献类型：
--
作者：
Peterka, RJ;Loughlin, PJ
人类的直立姿势本质上是不稳定的，需要根据来自感觉系统的空间定向信息采取纠正措施。人们可以从逻辑上预测，提供从多个感觉系统获得准确方位信息的环境将促进姿势稳定性。然而，我们发现，在一段时间后，在获得准确的感觉信息减少，恢复准确的信息破坏姿势稳定。在闭眼试验中，本体感受信息通过与身体摇摆成比例地旋转支撑表面（支撑表面“摇摆参考”）来改变。当支撑面返回到水平方向时，大多数受试者产生了短暂的1 Hz身体摇摆振荡，其与通常在安静站立期间观察到的低振幅身体摇摆显著不同。额外的实验表明，进一步增强的1-Hz的振荡时，表面从摇摆参考一个反向摇摆参考运动过渡。振荡行为下降，重复试验，表明学习效果。一个简单的负反馈控制模型的姿势控制系统预测发生这种1赫兹的振荡的条件下，太多的校正扭矩是成比例的身体摇摆。模型模拟用于区分产生过大校正扭矩的两种替代解释。模拟结果有利于解释的基础上的动态重新加权的感官贡献的姿势控制，而不是一个负载补偿机制，比例的固定组合的感官方向信息的扭矩。
Upright stance in humans is inherently unstable, requiring corrective action based on spatial-orientation information from sensory systems. One might logically predict that environments providing access to accurate orientation information from multiple sensory systems would facilitate postural stability. However, we show that, after a period in which access to accurate sensory information was reduced, the restoration of accurate information disrupted postural stability. In eyes-closed trials, proprioceptive information was altered by rotating the support surface in proportion to body sway (support surface "sway-referencing"). When the support surface returned to a level orientation, most subjects developed a transient 1-Hz body sway oscillation that differed significantly from the low-amplitude body sway typically observed during quiet stance. Additional experiments showed further enhancement of the 1-Hz oscillation when the surface transitioned from a sway-referenced to a reverse sway-referenced motion. Oscillatory behavior declined with repetition of trials, suggesting a learning effect. A simple negative feedback-control model of the postural control system predicted the occurrence of this 1-Hz oscillation in conditions where too much corrective torque is generated in proportion to body sway. Model simulations were used to distinguish between two alternative explanations for the excessive corrective torque generation. Simulation results favor an explanation based on the dynamic reweighting of sensory contributions to postural control rather than a load-compensation mechanism that scales torque in proportion to a fixed combination of sensory-orientation information.