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APAs Constraints to Voluntary Movements: The Case for Limb Movements Coupling
Fausto G Baldissera1, Luigi Tesio2,3
1RetiredMilan, Italy.
Frontiers in Human Neuroscience
|April 15, 2017
Summary
Rhythmic limb movements are easier in the same direction (ISO) than opposite (ANTI) due to interfering anticipatory postural commands. These commands facilitate ISO and hinder ANTI movements, impacting motor control and potentially rehabilitation.
Area of Science:
- Neuroscience
- Motor Control
- Biomechanics
Background:
- Rhythmic limb movements can be performed in isodirectional (ISO) or antidirectional (ANTI) patterns.
- ANTI movements are more challenging and prone to reverting to ISO, especially at higher frequencies.
Purpose of the Study:
- To investigate the neural mechanisms underlying the difficulty difference between ISO and ANTI limb movements.
- To explore the role of anticipatory postural commands (APAs) in motor control and coordination.
Main Methods:
- Experimental manipulation of hand and foot rhythmic movements (ISO and ANTI).
- Electromyography to measure muscle excitability and contractions.
- Analysis of cortical signals and their influence on motor pathways.
Main Results:
- Subliminal modulation of wrist muscle excitability facilitates ISO and hinders ANTI coupling.
- Anticipatory postural commands (APAs) interfere with voluntary commands during ANTI movements.
- Increased movement frequency amplifies APAs and postural effort, destabilizing ANTI coupling.
Conclusions:
- The dichotomy between easy (ISO) and difficult (ANTI) rhythmic limb movements is attributed to the interference of APAs.
- APAs play a crucial role in coordinating coupled limb movements and may be impaired in neurological diseases.
- Understanding APAs offers potential targets for motor rehabilitation and learning.