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Updated: Jun 12, 2026
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Intracortical Inhibition Within the Primary Motor Cortex Can Be Modulated by Changing the Focus of Attention
Published on: September 11, 2017
Cast immobilization increases long-interval intracortical inhibition
Brian C Clark1, Janet L Taylor, Richard L Hoffman
1Institute for Neuromusculoskeletal Research, Ohio University, Athens, Ohio 45701, USA. clarkb2@ohio.edu
Muscle & Nerve
|June 15, 2010
Summary
Immobilization significantly reduces muscle strength and central activation. Following immobilization, increased cortical inhibition during muscle contraction correlated with strength loss, suggesting neural adaptations.
Area of Science:
- Neuroscience
- Motor Control
- Human Physiology
Background:
- Muscle immobilization leads to performance decline and neural impairments.
- Cortical adaptations underlying these changes remain poorly understood.
Purpose of the Study:
- To investigate changes in cortical excitability, specifically intracortical facilitation (ICF) and inhibition (SICI, LICI), following immobilization.
- To assess the relationship between cortical adaptations, muscle strength loss, and central activation.
Main Methods:
- Healthy participants underwent 3 weeks of immobilization.
- Transcranial magnetic stimulation (TMS) assessed ICF, SICI, and LICI at rest and during contraction.
- Central activation and the H-reflex were also measured.
Main Results:
- Strength decreased by 43.2% and central activation by 24.3% after immobilization.
- No changes in ICF, SICI, or LICI were observed at rest.
- Long-interval intracortical inhibition (LICI) increased during contraction, correlating with strength loss (r = -0.63).
- The H-reflex increased post-immobilization.
Conclusions:
- Immobilization increases cortical inhibition during muscle contraction, potentially mediated by GABA(B) receptors.
- This enhanced inhibition is linked to strength reduction and may represent a neural adaptation to immobilization.
