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Experimental Brain Research

, Volume 159, Issue 2, pp 197–205 | Cite as

Motor skill training induces changes in the excitability of the leg cortical area in healthy humans

  • Monica A. Perez
  • Bjarke K. S. Lungholt
  • Kathinka Nyborg
  • Jens B. NielsenEmail author
Research Article

Abstract

Training-induced changes in cortical excitability may play an important role in rehabilitation of gait ability in patients with neurological disorders. In this study, we investigated the effect of a 32-min period of motor skill, non-skill and passive training involving the ankle muscles on leg motor cortical excitability in healthy humans. Transcranial magnetic stimulation (TMS) at a range of intensities was applied to obtain a recruitment curve of the motor evoked potentials (MEPs) in the tibialis anterior (TA) muscle before and after training. We also explored the effect of training on inhibitory and facilitatory cortical circuits by using a paired-pulse TMS technique at intervals of 2.5 ms (short-interval intracortical inhibition, SICI) and 8 ms (intracortical facilitation, ICF). During motor skill training, subjects were instructed to make a cursor follow a series of target lines on a computer screen by performing voluntary ankle dorsi- and plantarflexion movements. Non-skill and passive training consisted of repeated voluntary and assisted dorsi- and plantarflexion movements, respectively. Recruitment curves increased significantly after 32 min of motor skill training but not after non-skill and passive training, suggesting that only skill motor training increases motor cortical excitability. Motor skill training was not accompanied by any changes in the recruitment curves of TA MEPs evoked by transcranial electrical stimulation, suggesting that the increased MEPs to TMS was likely caused by changes in excitability at a cortical site. SICI was decreased after 32 min of motor skill training but no changes were observed in ICF. We conclude that similar plastic changes as have previously been reported for the hand motor following motor skill training may also be observed for the leg motor area. The observed plastic changes appeared to be related to the degree of difficulty in the motor task, and may be of relevance for rehabilitation of gait disorders.

Keywords

Corticospinal tract Intracortical circuits Plasticity Transcranial magnetic stimulation 

Notes

Acknowledgements

The authors are very grateful to Torill Bjugan, Dinah Merklin and Lene Østerby for their help during this study. This work was supported by grants from the Danish Health Research Council, The Danish Society of Multiple Sclerosis, The Novo Nordisk Foundation and The Danish Ministry of Culture.

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Copyright information

© Springer-Verlag 2004

Authors and Affiliations

  • Monica A. Perez
    • 1
  • Bjarke K. S. Lungholt
    • 1
  • Kathinka Nyborg
    • 1
  • Jens B. Nielsen
    • 1
    Email author
  1. 1.Department of Medical Physiology, Panum InstituteUniversity of CopenhagenCopenhagen NDenmark

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