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Dynamic regulation of sensorimotor integration in human postural control
Robert J Peterka1, Patrick J Loughlin
1Neurological Sciences Institute, Oregon Health & Science University, Portland, Oregon 97006, USA. peterkar@ohsu.edu
Journal of Neurophysiology
|September 19, 2003
Summary
Humans need sensory information for balance. Surprisingly, restoring accurate sensory input after a period of reduced accuracy can disrupt postural stability, causing body sway oscillations. This highlights complex sensory reweighting in balance control.
Area of Science:
- Human postural control
- Sensory integration
- Motor learning
Background:
- Upright human stance is unstable and relies on sensory systems for stability.
- Accurate spatial-orientation information from multiple senses is presumed to enhance postural control.
Purpose of the Study:
- To investigate the effect of restoring accurate sensory information on postural stability after a period of reduced accuracy.
- To explore the mechanisms underlying transient postural sway oscillations.
Main Methods:
- Subjects stood with eyes closed while the support surface was sway-referenced (rotated with body sway).
- Postural stability was assessed upon return to a level surface, with variations including reverse sway-referencing.
- A negative feedback-control model simulated postural dynamics.
Main Results:
- Restoring accurate proprioceptive information after sway-referencing induced a transient 1-Hz body sway oscillation.
- This oscillation was enhanced by transitioning to reverse sway-referencing.
- Oscillations decreased with trial repetition, indicating a learning effect.
Conclusions:
- Postural control can be disrupted by the sudden restoration of accurate sensory information.
- The 1-Hz oscillation suggests excessive corrective torque generation, likely due to dynamic sensory reweighting rather than load compensation.