Ratio of shear to load ground-reaction force may underlie the directional tuning of the automatic postural response to rotation and translation.
Ratio of shear to load ground-reaction force may underlie the directional tuning of the automatic postural response to rotation and translation.
复制标题
剪切力与负载地面反作用力的比率可能是对旋转和平移的自动姿势响应的方向调整的基础。
DOI：
10.1152/jn.00773.2003
复制
发表时间：
2004
影响因子：
2.5
通讯作者：
Macpherson,JaneM
中科院分区：
文献类型：
--
作者：
Ting,LenaH;Macpherson,JaneM
本研究试图识别的感觉信号，编码扰动方向足够快的形状自动姿势反应的方向调谐。我们比较了自由站立的猫在水平面上对16个方向的俯仰和滚动旋转以及16个方向的线性平移的反应。在相对于脚的相同方向上移动质心的旋转和平移诱发了类似的肌肉活动和主动地面反作用力模式，这表明存在一种单一的、稳健的姿势策略来稳定旋转和平移中的质心。因此，我们假设应该有一个共同的感觉输入，编码的扰动的方向，并导致姿势反应的早期肌电爆发的方向调谐。我们比较了主动姿势反应之前旋转和平移引起的机械变化。在旋转和平移方向的整个范围内，唯一一致的共同特征是地面反作用力角度的初始变化。其他变量，包括关节角度，地面反作用力的大小，压力中心，并在空间中的质量中心显示出相反的或不显着的变化旋转和平移。爪处的力角度的变化反映了加载力与滑动力的比率，类似于手指抓握任务期间的滑动。我们建议，皮肤传感器在脚底检测地面反作用力角度的变化，并提供关键的输入方向调整的自动姿势反应的平衡。
This study sought to identify the sensory signals that encode perturbation direction rapidly enough to shape the directional tuning of the automatic postural response. We compared reactions to 16 directions of pitch and roll rotation and 16 directions of linear translation in the horizontal plane in freely standing cats. Rotations and translations that displaced the center of mass in the same direction relative to the feet evoked similar patterns of muscle activity and active ground-reaction force, suggesting the presence of asingle, robust postural strategy for stabilizing the center of mass in both rotation and translation. Therefore we postulated there should be a common sensory input that encodes the direction of the perturbation and leads to the directional tuning of the early electromyographic burst in the postural response. We compared the mechanical changes induced by rotations and translations prior to the active, postural response. The only consistent feature common to the full range of rotation and translation directions was the initial change in ground-reaction force angle. Other variables including joint angles, ground-reaction force magnitudes, center of pressure, and center of mass in space showed opposite or nonsignificant changes for rotation and translation. Change in force angle at the paw reflects the ratio of loading force to slip force, analogous to slips during finger grip tasks. We propose that cutaneous sensors in the foot soles detect change in ground-reaction force angle and provide the critical input underlying the directional tuning of the automatic postural response for balance.