Experimental Brain Research

, Volume 122, Issue 1, pp 79–84

Facilitation of muscle evoked responses after repetitive cortical stimulation in man

Authors

  • A. Berardelli
    • Dipartimento Scienze Neurologiche, Viale Università n. 30, I-00185 Rome, Italy Tel.: +39-6-4991-4700, Fax: +39-6-4991-4302
  • M. Inghilleri
    • Dipartimento Scienze Neurologiche, Viale Università n. 30, I-00185 Rome, Italy Tel.: +39-6-4991-4700, Fax: +39-6-4991-4302
  • J. C. Rothwell
    • MRC Human Movement and Balance Unit, Institute of Neurology, London, UK
  • S. Romeo
    • Dipartimento Scienze Neurologiche, Viale Università n. 30, I-00185 Rome, Italy Tel.: +39-6-4991-4700, Fax: +39-6-4991-4302
  • A. Currà
    • Dipartimento Scienze Neurologiche, Viale Università n. 30, I-00185 Rome, Italy Tel.: +39-6-4991-4700, Fax: +39-6-4991-4302
  • F. Gilio
    • Dipartimento Scienze Neurologiche, Viale Università n. 30, I-00185 Rome, Italy Tel.: +39-6-4991-4700, Fax: +39-6-4991-4302
  • N. Modugno
    • Dipartimento Scienze Neurologiche, Viale Università n. 30, I-00185 Rome, Italy Tel.: +39-6-4991-4700, Fax: +39-6-4991-4302
  • M. Manfredi
    • Dipartimento Scienze Neurologiche, Viale Università n. 30, I-00185 Rome, Italy Tel.: +39-6-4991-4700, Fax: +39-6-4991-4302
RESEARCH ARTICLE

DOI: 10.1007/s002210050493

Cite this article as:
Berardelli, A., Inghilleri, M., Rothwell, J. et al. Exp Brain Res (1998) 122: 79. doi:10.1007/s002210050493

Abstract 

The technique of repetitive transcranial magnetic stimulation (rTMS) allows cortical motor areas to be activated by trains of magnetic stimuli at different frequencies and intensities. In this paper, we studied long-term neurophysiological effects of rTMS delivered to the motor cortex at 5 Hz with an intensity of 120% of motor threshold. Each stimulus of the train produced muscle-evoked potentials (MEPs) in hand and forearm muscles, which gradually increased in size from the first to the last shock. After the end of the train, the response to a single-test stimulus remained enhanced for 600–900 ms. In contrast, the train had no effect on the size of the MEPs evoked by transcranial electrical stimulation, while it suppressed H-reflexes in forearm muscles for 900 ms. We conclude that rTMS of these parameters increases the excitability of the motor cortex and that this effect outlasts the train for almost 1 s. At the spinal level, rTMS may increase presynaptic inhibition of Ia afferent fibers responsible for the H-reflex.

Key words Motor cortexMagnetic stimulationRepetitive stimulation

Copyright information

© Springer-Verlag Berlin Heidelberg 1998