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Corticospinal Excitability Modulation During Action Observation
Published on: December 31, 2013
Human corticospinal excitability during a precued reaction time paradigm
Steven McMillan1, Vincent Nougier, Winston D Byblow
1Department of Sport and Exercise Science, University of Auckland, Tamaki Campus, Auckland, New Zealand.
Experimental Brain Research
|December 20, 2003
Summary
Corticospinal excitability during reaction time (RT) tasks is modulated by precue information. Greater excitability was observed when less movement information was provided, potentially to compensate for increased RT.
Area of Science:
- Neuroscience
- Motor Control
- Human Movement Science
Background:
- Reaction time (RT) is influenced by the predictability of upcoming movements.
- Corticospinal excitability plays a crucial role in motor preparation and execution.
Purpose of the Study:
- To investigate the time-course of corticospinal excitability during RT tasks.
- To compare corticospinal excitability under different precue conditions (full, direction-only, none).
Main Methods:
- Ten healthy subjects performed a four-choice RT task involving wrist flexion/extension.
- Transcranial magnetic stimulation (TMS) was used to probe corticospinal excitability.
- Motor-evoked potential (MEP) amplitude was analyzed in relation to TMS onset.
Main Results:
- A significant relationship between MEP amplitude and TMS onset was observed, explainable by the Boltzmann equation.
- Corticospinal excitability was significantly different between conditions with and without precue information.
- Modulation of excitability was greater in the flexor carpi radialis (FCR) than extensor carpi radialis (ECR).
Conclusions:
- Corticospinal excitability is not altered by movement extent specification but is influenced by movement direction precues.
- Increased corticospinal tract gain may compensate for longer RTs when less precue information is available.
- Precue information significantly modulates motor preparation and corticospinal excitability during RT tasks.
