Brain excitability and electroencephalographic activation: non-invasive evaluation in healthy humans via transcranial magnetic stimulation
| Autor: | P.M. Rossini, Maria D. Caramia, M.T. Desiato, F. Lavaroni |
|---|---|
| Rok vydání: | 1991 |
| Předmět: |
Male
medicine.medical_specialty medicine.medical_treatment Alpha (ethology) Stimulation Electroencephalography Audiology Forearm Reference Values Reflex medicine Humans Evoked potential Molecular Biology Evoked Potentials Vision Ocular Motor Neurons medicine.diagnostic_test General Neuroscience Muscles Motor Cortex Brain Transcranial Magnetic Stimulation Transcranial magnetic stimulation Electrophysiology medicine.anatomical_structure Anesthesia Female Neurology (clinical) H-reflex Psychology Developmental Biology |
| Zdroj: | Brain research. 567(1) |
| ISSN: | 0006-8993 |
| Popis: | Excitability changes of the central motor tracts as a function of the electroencephalographic (EEG) characteristics has been investigated in 10 healthy volunteers. Transcranial magnetic stimulation (TCS) was administered to the right motor cortex with an intensity 5-10% above threshold for the elicitation of motor evoked potentials (MEPs) in the left forearm muscles. Simultaneously, the right median nerve was stimulated to provoke an H-reflex in the forearm flexors and EEG activity was recorded from the left hemiscalp. Subjects were completely relaxed and were asked at random either to keep the eyes closed while maintaining mental inactivity (A) or to open their eyes and perform mental arithmetics (B). Latencies and amplitudes of MEPs and H-reflexes were statistically matched with the spectral content of the EEG. In condition A, MEPs of 119 +/- 61 microV, with up to 36% of missing responses and background EEG activity dominated by rhythms in the alpha range were found. In condition B, MEPs of 219 +/- 66 microV (P less than 0.001), with less than 16% of missing responses, 'blocking' of the background alpha rhythms, and a potentiation of the faster ones' relative power were observed. Changes of the H-reflex characteristics were neither statistically significant nor related to MEP amplitude and EEG spectral profile fluctuations. |
| Databáze: | OpenAIRE |
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