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A basic posture control mechanism: the stabilization of the centre of gravity
1Department of Clinical Neurology and Neurophysiology, University of Freiburg, F.R.G.
Electroencephalography and Clinical Neurophysiology
|August 1, 1990
Summary
Maintaining upright posture relies on stabilizing the body's center of gravity. This study reveals a gravity-dependent receptor system in joints and the spine, crucial for postural control.
Area of Science:
- Human physiology
- Biomechanics
- Neuroscience
Background:
- Upright stance stabilization is critical for human posture.
- Visual, vestibular, and proprioceptive systems contribute to sway stabilization.
- A gravity-dependent receptor system may signal center of gravity relative to the support surface.
Purpose of the Study:
- To investigate the properties of a proposed gravity-dependent receptor system.
- To evaluate the role of this system in postural stabilization.
- To identify the location and nature of these receptors.
Main Methods:
- Simulated microgravity using water immersion.
- Electromyography (EMG) to measure leg muscle responses.
- Experiment involving varying contact forces and body weight loading.
Main Results:
- An approximately linear relationship was observed between contact force and EMG response amplitudes.
- Loading subjects out of water did not further increase response amplitude.
- A body weight-dependent gain control mechanism for postural reflexes was demonstrated.
Conclusions:
- A novel, gravity-dependent receptor system contributes to postural stabilization.
- This system appears to involve force-dependent receptors located in joints and the vertebral column.
- Postural reflexes exhibit a gain control mechanism influenced by body weight.