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Modification of the human motor cortex by associative stimulation
1Department of Medical Physiology, Panum Institute, University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen, Denmark.
Experimental Brain Research
|July 28, 2004
Summary
Associative stimulation enhances motor cortex excitability by increasing motor evoked potentials and intracortical facilitation. This suggests that changes in excitatory circuits underlie motor cortex reorganization.
Area of Science:
- Neuroscience
- Motor Control
- Neuroplasticity
Background:
- Motor cortex reorganization can be induced by altering sensory input.
- Paired electrical stimulation of hand muscles (
- associative stimulation
- ) increases corticospinal excitability.
- Mechanisms underlying this plasticity require further investigation.
Purpose of the Study:
- To investigate the mechanisms behind motor cortex excitability changes after associative stimulation.
- To determine which intracortical circuits are affected by this stimulation protocol.
Main Methods:
- Utilized transcranial magnetic stimulation (TMS) to assess cortical excitability.
- Measured motor evoked potentials (MEPs), intracortical inhibition (ICI), intracortical facilitation (ICF), and short-interval intracortical facilitation (SICF).
- Applied 1 hour of associative stimulation to hand muscles.
Main Results:
- A significant increase in MEP amplitudes was observed in stimulated hand muscles.
- Intracortical facilitation (ICF) and short-interval intracortical facilitation (SICF) increased significantly.
- No significant changes were found in intracortical inhibition (ICI).
Conclusions:
- Confirms that 1 hour of associative stimulation enhances motor cortex excitability.
- Suggests that modifications in intracortical excitatory circuits are responsible for the observed plasticity.
- Highlights the role of ICF and SICF in motor cortex reorganization.