Changes in motor cortex excitability for the trained and non-trained hand after long-term unilateral motor training.
Repetitive unilateral upper limb motor training does not only affect behavior but also increases excitability of the contralateral primary motor cortex (M1). The behavioral gain is partially transferred to the non-trained side. Changes in M1 intracortical facilitation (ICF) might as well be observed for both hand sides. We measured ICF of both left and right abductor pollicis brevis muscles (APB) before and after a two-week period of arm ability training (AAT) of the left hand in 13 strongly right handed healthy volunteers. Performance with AAT-tasks improved for both the left trained and right untrained hand. ICF for the untrained hand decreased over training while it remained unchanged for the left trained hand. Decrease of ICF for the right hand was moderately associated with an increase of AAT-performance for the untrained right hand. We conclude that ICF-imbalance between dominant and non-dominant hand is sensitive to long-term motor training: training of the non-dominant hand results in a decrease of ICF of the dominant hand. The ICF-decrease is associated with a transfer of training-induced improvement of performance from the non-dominant to the dominant hand.
Department for Neurology, University of Greifswald, Germany.
Matthias
M
Grothe
Functional Imaging Unit, Center for Diagnostic Radiology, University of Greifswald, Germany.
Karla
K
Doppl
Functional Imaging Unit, Center for Diagnostic Radiology, University of Greifswald, Germany.
Charlotte
C
Roth
BDH-Klinik Greifswald, Neurorehabilitation Centre and Spinal Cord Injury Unit, University of Greifswald, Germany.
Sybille
S
Roschka
BDH-Klinik Greifswald, Neurorehabilitation Centre and Spinal Cord Injury Unit, University of Greifswald, Germany.
Thomas
T
Platz
Functional Imaging Unit, Center for Diagnostic Radiology, University of Greifswald, Germany. Electronic address: martin.lotze@uni-greifswald.de.
Martin
M
Lotze
D000328:Adult; D004292:Dominance, Cerebral; D015444:Exercise; D005260:Female; D006225:Hand / Q000502:physiology*; D006801:Humans; D008297:Male; D009044:Motor Cortex / Q000502:physiology*; D009068:Movement; D018482:Muscle, Skeletal / Q000502:physiology*; D011597:Psychomotor Performance; D050781:Transcranial Magnetic Stimulation; D055815:Young Adult
Excitability; ICI; Long-term training; Primary motor cortex; TMS