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Corticospinal Excitability Modulation During Action Observation
Published on: December 31, 2013
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Sensorimotor uncertainty modulates corticospinal excitability during skilled object manipulation.
Marco Davare1,2, Pranav J Parikh3,4, Marco Santello4
1Department of Movement Sciences and Leuven Brain Institute, KU Leuven, Leuven , Belgium.
Journal of Neurophysiology
|February 7, 2019
Summary
Sensorimotor memory aids grasp force planning, but unpredictable object contact shifts control to feedback mechanisms. Corticospinal excitability changes after contact reveal this adaptive sensorimotor processing.
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Area of Science:
- Neuroscience
- Motor Control
- Human Sensorimotor System
Background:
- Sensorimotor memory enables feedforward grasp force planning when contact points are stable.
- Unpredictable grasp locations increase trial-to-trial variability, necessitating adaptive force modulation.
- This suggests a shift from memory-based to feedback-based control mechanisms.
Purpose of the Study:
- To investigate sensorimotor transformation mechanisms during object manipulation.
- To determine how fingertip placement uncertainty influences the reliance on memory versus feedback control.
- To examine the role of corticospinal excitability in response to sensorimotor uncertainty.
Main Methods:
- Subjects grasped and lifted an object with an asymmetrical center of mass.
- Two conditions manipulated fingertip position predictability while keeping average position and force distribution similar.
- Corticospinal excitability was measured using transcranial magnetic stimulation.
Main Results:
- Sensorimotor uncertainty affected corticospinal excitability after object contact, but not before.
- This indicates a rapid tuning of sensorimotor integration post-contact.
- The findings support a shift in control mechanisms based on digit placement predictability.
Conclusions:
- The balance between predictive (memory-based) and feedback mechanisms in force control depends on grasp predictability.
- Distinct sensorimotor integration processes are engaged based on the need for feedback versus memory.
- Corticospinal excitability shortly after contact reflects the processing demands of these distinct mechanisms.