Facial nerve injury-induced disinhibition in the primary motor cortices of both hemispheres
| Autor: | Tamás Farkas, János A. Perge, Joachim R. Wolff, József Toldi, Zsolt Kis |
|---|---|
| Rok vydání: | 2000 |
| Předmět: |
Denervation
Trigeminal nerve 0303 health sciences General Neuroscience Nerve injury Facial nerve 03 medical and health sciences 0302 clinical medicine medicine.anatomical_structure Disinhibition medicine Sensory cortex medicine.symptom Primary motor cortex Psychology Neuroscience 030217 neurology & neurosurgery 030304 developmental biology Sensory nerve |
| Zdroj: | European Journal of Neuroscience. 12:2190-2194 |
| ISSN: | 0953-816X |
| DOI: | 10.1046/j.1460-9568.2000.00096.x |
| Popis: | Unilateral facial nerve transection induces plastic reorganization of the somatotopic order in the primary motor cortex area (MI). This process is biphasic and starts with a transient disinhibition of connections between cortical areas in both hemispheres. Little is known about the underlying mechanisms. Here, cortical excitability has been studied by paired pulse electrical stimulation, applied either within the MI or peripherally to the trigeminal nerve, while the responses were recorded bilaterally in the MI. The ratios between the amplitudes of the second and first evoked potentials (EPs or fEPSPs) were taken as measures of the inhibitory capacity in the MI ipsilateral or contralateral to the nerve injury. A skin wound or unilateral facial nerve exposure immediately caused a transient facilitation, which was followed by a reset to some level of inhibition in the MI on both sides. After facial nerve transection, the first relatively mild reduction of inhibition started shortly (within 10 min) after denervation. This was followed by a second step, involving a stronger decrease in inhibition, 40-45 min later. Previous publications have proved that sensory nerve injury (deafferentation) induces disinhibition in corresponding areas of the sensory cortex. It is now demonstrated that sham operation and, to an even greater extent, unilateral transection of the purely motoric facial nerve (deefferentation), each induce extended disinhibition in the MIs on both sides. |
| Databáze: | OpenAIRE |
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