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Stimulating the Lip Motor Cortex with Transcranial Magnetic Stimulation
Published on: June 14, 2014
Changes in the perioral muscle responses to cortical TMS induced by decrease of sensory input and electrical
Summary
Lower facial anesthesia causes rapid brain changes, enhancing motor cortex activity in both hemispheres. Repetitive electrical stimulation did not significantly alter motor cortex responses.
Area of Science:
- Neuroscience
- Motor Control
- Neuroplasticity
Background:
- The motor cortex controls voluntary movements, including facial expressions.
- Understanding cortical plasticity is crucial for rehabilitation after neurological injury.
Purpose of the Study:
- To investigate how repetitive electrical stimulation and local anesthesia in the lower face affect the motor cortex.
- To explore rapid neuroplastic changes in response to sensory input modulation.
Main Methods:
- Cortical motor evoked potentials (MEPs) were recorded using transcranial magnetic stimulation in subjects undergoing repetitive electrical stimulation or local facial anesthesia.
- Repetitive electrical stimulation was applied at 5 Hz to the cheek.
- Local anesthesia (lidocaine/prilocaine cream) was applied to the lip-cheek region.
Main Results:
- Repetitive electrical stimulation showed no significant changes in perioral MEPs.
- Lower facial anesthesia led to a significant increase in cortical MEP amplitude, particularly on the ipsilateral and contralateral sides.
- Contralateral perioral MEPs also showed increased amplitude during anesthesia.
Conclusions:
- Topical anesthesia of the lower face induces significant cortical modulation.
- Fast plastic changes occur in both brain hemispheres, directed towards the non-anesthetized side.
