Mergner T, Maurer C, Peterka R J
Neurological University Clinic, Freiburg, Germany.
Prog Brain Res. 2003;142:189-201. doi: 10.1016/S0079-6123(03)42014-1.
We present a multisensory postural control model based on experiments where the balance in normal subjects and vestibular loss patients was perturbed by application of external torque produced by force-controlled pull stimuli. The stimuli were applied while subjects stood on a stationary or body-sway-referenced motion platform with eyes closed and auditory cues masked. Excursions of the center of mass (COM) and the center of pressure (COP) were analyzed using a systems analysis approach. The results were compared to an 'inverted pendulum' model of posture control. The model receives input from four sensors: ankle proprioceptors, semicircular canals, otoliths, and plantar pressure sensors (somatosensory graviceptors). Sensor fusion mechanisms are used to yield separate internal representations of foot support motion, gravity, and external torque (pull). These representations are fed as global set point signals into a local control loop based on ankle proprioceptive negative feedback. This set point control upgrades the proprioceptive body-on-foot (support) stabilization into a body-in-space control which compensates for support tilt, gravity, and contact forces. This compensation occurs even when the stimuli are combined or a voluntary lean is superimposed. Model simulations paralleled our experimental findings.
我们基于实验提出了一种多感官姿势控制模型。在实验中，通过施加由力控牵拉刺激产生的外部扭矩，扰乱正常受试者和前庭功能丧失患者的平衡。刺激施加时，受试者闭眼站在固定或身体摆动参考运动平台上，同时听觉线索被屏蔽。使用系统分析方法分析质心（COM）和压力中心（COP）的偏移。将结果与姿势控制的“倒立摆”模型进行比较。该模型从四个传感器接收输入：踝关节本体感受器、半规管、耳石和足底压力传感器（体感重力感受器）。传感器融合机制用于产生足部支撑运动、重力和外部扭矩（牵拉）的单独内部表征。这些表征作为全局设定点信号输入到基于踝关节本体感受负反馈的局部控制回路中。这种设定点控制将本体感受的足部对身体（支撑）稳定提升为空间中身体控制，以补偿支撑倾斜、重力和接触力。即使刺激组合或叠加了自愿倾斜，这种补偿也会发生。模型模拟与我们的实验结果相似。
