A Feedback Model Reproduces Muscle Activity During Human Postural Responses to Support-Surface Translations
| Autor: | Torrence D. J. Welch, Lena H. Ting |
|---|---|
| Rok vydání: | 2008 |
| Předmět: |
Adult
Male medicine.medical_specialty Adolescent Physiology Posture Kinematics Models Biological Motion (physics) Displacement (vector) Feedback Acceleration Physical medicine and rehabilitation medicine Humans Muscle Skeletal Set (psychology) Postural Balance Mathematics Electromyography General Neuroscience Pendulum Optimal control Biomechanical Phenomena medicine.anatomical_structure Female Ankle |
| Zdroj: | Journal of Neurophysiology. 99:1032-1038 |
| ISSN: | 1522-1598 0022-3077 |
| DOI: | 10.1152/jn.01110.2007 |
| Popis: | Although feedback models have been used to simulate body motions in human postural control, it is not known whether muscle activation patterns generated by the nervous system during postural responses can also be explained by a feedback control process. We investigated whether a simple feedback law could explain temporal patterns of muscle activation in response to support-surface translations in human subjects. Previously, we used a single-link inverted-pendulum model with a delayed feedback controller to reproduce temporal patterns of muscle activity during postural responses in cats. We scaled this model to human dimensions and determined whether it could reproduce human muscle activity during forward and backward support-surface perturbations. Through optimization, we found three feedback gains (on pendulum acceleration, velocity, and displacement) and a common time delay that allowed the model to best match measured electromyographic (EMG) signals. For each muscle and each subject, the entire time courses of EMG signals during postural responses were well reconstructed in muscles throughout the lower body and resembled the solution derived from an optimal control model. In ankle muscles, >75% of the EMG variability was accounted for by model reconstructions. Surprisingly, >67% of the EMG variability was also accounted for in knee, hip, and pelvis muscles, even though motion at these joints was minimal. Although not explicitly required by our optimization, pendulum kinematics were well matched to subject center-of-mass (CoM) kinematics. Together, these results suggest that a common set of feedback signals related to task-level control of CoM motion is used in the temporal formation of muscle activity during postural control. |
| Databáze: | OpenAIRE |
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