A Feedback Model Explains the Differential Scaling of Human Postural Responses to Perturbation Acceleration and Velocity

摘要: Although the neural basis of balance control remains unknown, recent studies suggest that a feedback law on center-of-mass (CoM) kinematics determines temporal patterning muscle activity during human postural responses. We hypothesized same would also explain variations in to support-surface translation as perturbation characteristics vary. Subject CoM motion was experimentally modulated using 34 different anterior–posterior translations varying peak acceleration and velocity but total displacement. Electromyographic (EMG) recordings from several muscles lower limbs trunk were compared predicted EMG patterns an inverted pendulum model under delayed control. In both recorded patterns, initial burst scaled linearly with acceleration, whereas tonic “plateau” region velocity. The relatively invariant duration modeled by incorporating transient, time-limited encoding inspired spindle primary afferent dynamic entire time course favorably across all conditions, suggesting is not generated feedforward mechanisms. Perturbation conditions presented randomly subjects maintained constant gains conditions. contrast, optimal solution based trade-off between stabilization energy expenditure should change characteristics. These results used generate variety disturbances.