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Updated: May 15, 2026
08:12
Experimental Methods to Study Human Postural Control
Published on: September 11, 2019
Does the nervous system use equilibrium-point control to guide single and multiple joint movements?
E Bizzi1, N Hogan, F A Mussa-Ivaldi
1Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, Electronic mail: emilio@wheaties.ai.mit.edu.
The Behavioral and Brain Sciences
|January 11, 2013
Summary
The central nervous system may generate movement by shifting limb equilibrium posture. This equilibrium-point hypothesis simplifies complex motor control and can be tested using spinal cord microstimulation.
Area of Science:
- Neuroscience
- Motor Control
- Biophysics
Background:
- The equilibrium-point hypothesis proposes that the central nervous system (CNS) generates movement by altering the limb's equilibrium posture.
- This hypothesis simplifies the complex computations required for multijoint movements and interactions with the environment.
Purpose of the Study:
- To provide experimental evidence for the equilibrium-point hypothesis of motor control.
- To investigate the neurophysiological basis of this hypothesis within the spinal cord.
Main Methods:
- Review of existing psychophysical and behavioral experiments supporting the hypothesis.
- Description of recent neurophysiological experiments involving microstimulation of the frog spinal cord's premotoneural network.
Main Results:
- Prior evidence from human studies supports the hypothesis for single- and multijoint limb movements.
- Microstimulation of the frog spinal cord elicits leg movements, indicating a direct link to motor output.
Conclusions:
- The equilibrium-point hypothesis offers a unified framework for understanding posture, movement, and contact tasks.
- The study demonstrates that the hypothesis is now testable within the neurophysiological mechanisms of the spinal cord.
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