Intermittent coupling between grip force and load force during oscillations of a hand-held object
Francis Grover1, Maurice Lamb1, Scott Bonnette2
1Center for Cognition, Action, and Perception, Department of Psychology, ML 0376, Edwards Center 1, University of Cincinnati, Cincinnati, OH, 45221-0376, USA.
Experimental Brain Research
|June 23, 2018
Summary
Grip force and load force coordination is not always stable and continuous. This study reveals intermittent coordination and varying stability during load force changes, challenging previous assumptions about motor control anticipation.
Area of Science:
- Neuroscience
- Motor Control
- Biomechanics
Background:
- Grip force adaptations to load forces were previously thought to be continuous, stable, and proportional.
- Sensorimotor feedback delays necessitate predictive mechanisms (internal models) for anticipatory grip force control.
- Recent evidence suggests grip force-load force coupling stability is less persistent than assumed.
Purpose of the Study:
- To comprehensively quantify the time-varying dynamics of grip force-load force coupling.
- To investigate the stability and coordination patterns during dynamic load force changes.
- To re-evaluate the role of predictive mechanisms in motor control.
Main Methods:
- Participants performed grip tasks with oscillating load forces for 30-second intervals.
- Analysis focused on quantifying the time-varying characteristics of grip force and load force coupling.
- Investigated intermittent phases of coordination and stability variations.
Main Results:
- Grip force-load force coupling exhibited intermittent phases of coordination, not continuous stability.
- The stability of the coupling varied significantly over time during load force oscillations.
- Findings contradict the notion of a persistently stable grip force-load force relationship.
Conclusions:
- Grip force-load force coupling is characterized by dynamic and intermittent coordination, not constant stability.
- The findings challenge existing models relying on persistent internal models for anticipatory grip force control.
- Motor control anticipation may involve more flexible and context-dependent mechanisms than previously understood.
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