Interindividual variability of the modulatory effects of repetitive transcranial magnetic stimulation on cortical excitability

Repetitive transcranial magnetic stimulation (rTMS) appears to have effects on cortical excitability that extend beyond the train of rTMS itself. These effects may be inhibitory or facilitatory and appear to depend on the frequency, intensity, duration and intertrain interval of the rTMS. Many studi...

Descripción completa

Detalles Bibliográficos
Autores: Maeda, F., Keenan, Julian P., Tormos Muñoz, José María, Topka, Helge, Pascual Leone, Álvaro
Tipo de recurso: artículo
Fecha de publicación:2000
País:España
Institución:Universidad Católica de Valencia San Vicente Mártir
Repositorio:RIUCV. Repositorio de la Universidad Católica de Valencia San Vicente Mártir
Idioma:inglés
OAI Identifier:oai:riucv.ucv.es:20.500.12466/3318
Acceso en línea:http://hdl.handle.net/20.500.12466/3318
Access Level:acceso abierto
Palabra clave:Repetitive transcranial magnetic stimulation (rTMS)
Train
Frequency tuning curve
Cortical excitability
Neurophysiology
2410 Biología Humana
2490 Neurociencias
Descripción
Sumario:Repetitive transcranial magnetic stimulation (rTMS) appears to have effects on cortical excitability that extend beyond the train of rTMS itself. These effects may be inhibitory or facilitatory and appear to depend on the frequency, intensity, duration and intertrain interval of the rTMS. Many studies assume facilitatory effects of high-frequency rTMS and inhibitory effects of low-frequency rTMS. Nevertheless, the interindividual variability of this modulation of cortical excitability by rTMS has not been systematically investigated. In this study, we applied 240 pulses of rTMS at 90% of the subjects' motor threshold to their motor cortex at different frequencies (1, 10, 15 and 20 Hz) and examined the effects on motor evoked potentials (frequency tuning curve). Although the averaged group data showed a frequency-dependent increase in cortical excitability, each subject had a different pattern of frequency tuning curve, i.e. a different modulatory effect on cortical excitability at different rTMS frequencies. The interindividual variability of these modulatory effects was still high, though less so, when the number of rTMS pulses was increased to 1600. These findings illustrate the degree of variability of the rTMS effects in the human brain.