English
 
User Manual Privacy Policy Disclaimer Contact us
  Advanced SearchBrowse

Item

ITEM ACTIONSEXPORT

Released

Journal Article

Bilateral changes in excitability of sensorimotor cortices during unilateral movement: Combined electroencephalographic and transcranial magnetic stimulation study

MPS-Authors
There are no MPG-Authors available
Locator
There are no locators available
Fulltext (public)
There are no public fulltexts available
Supplementary Material (public)
There is no public supplementary material available
Citation

Kičić, D., Lioumis, P., Ilmoniemi, R. J., & Nikulin, V. V. (2008). Bilateral changes in excitability of sensorimotor cortices during unilateral movement: Combined electroencephalographic and transcranial magnetic stimulation study. Neuroscience, 152(4), 1119-1129. doi:10.1016/j.neuroscience.2008.01.043.


Cite as: http://hdl.handle.net/11858/00-001M-0000-002D-417F-5
Abstract
It remains unclear what neuronal mechanisms in humans are reflected in the activation of the ipsilateral hemisphere during the performance of unilateral movements. To address this question we combined transcranial magnetic stimulation (TMS), electroencephalography (EEG), and electromyographic (EMG) recordings of motor evoked potentials (MEPs). Compared with previous TMS studies, where changes in excitability might be related to both cortical and spinal mechanisms, our setup allowed a more direct evaluation of the cortical processes related to the performance of unilateral movements. EEG responses showed that the unilateral motor reactions were associated with the bilateral increase in the excitability of sensorimotor cortices. However, this increase was smaller in the ipsilateral hemisphere most likely due to the fact that the excitation in ipsilateral hemisphere coincided with additional inhibitory processes related to the suppression of mirror movements. This explanation was further corroborated by showing that only contralateral changes in cortical excitability led to the increase in the amplitude of peripheral MEPs, while neuronal activation in the ipsilateral hemisphere was not associated with the changes in the muscle responses. These results suggest that the increased excitability in the ipsilateral hemisphere was uncoupled from the modulation of the cortico-spinal output. Moreover, we show that the background neuronal activity during unilateral movements was different in the ipsi- and contralateral hemisphere. This difference most likely reflects inter-hemispheric balance between the excitation and inhibition which is required for the optimal performance of the unilateral movement.