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Neural Plasticity
Volume 2013 (2013), Article ID 613197, 12 pages
http://dx.doi.org/10.1155/2013/613197
Research Article

Trains of Epidural DC Stimulation of the Cerebellum Tune Corticomotor Excitability

1Service de Neurochirurgie, CHU Saint-Pierre-ULB, 1070 Bruxelles, Belgium
2FNRS Neurologie, Unité d’Etude du Mouvement, Hôpital Erasme-ULB, 808 Route de Lennik, 1070 Bruxelles, Belgium

Received 8 March 2013; Accepted 4 April 2013

Academic Editor: José María Delgado-Garcia

Copyright © 2013 Nordeyn Oulad Ben Taib and Mario Manto. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

We assessed the effects of anodal/cathodal direct current stimulation (DCS) applied epidurally over the cerebellum. We studied the excitability of both the motor cortex and the anterior horn of the spinal cord in adult rats under continuous anesthesia. We also investigated the effects on the spatial representation of a couple of agonist/antagonist muscles on primary motor cortex. Moreover, we evaluated the effects on the afferent inhibition in a paradigm of conditioned corticomotor responses. Anodal DCS of the cerebellum (1) decreased the excitability of the motor cortex, (2) reduced the excitability of waves, as shown by the decrease of both mean /mean ratios and persistence of waves, (3) exerted a “smoothing effect” on corticomotor maps, reshaping the representation of muscles on the motor cortex, and (4) enhanced the afferent inhibition of conditioned motor evoked responses. Cathodal DCS of the cerebellum exerted partially reverse effects. DCS of the cerebellum modulates the excitability of both motor cortex and spinal cord at the level of the anterior horn. This is the first demonstration that cerebellar DCS tunes the shape of corticomotor maps. Our findings provide a novel mechanism by which DCS of the cerebellum exerts a remote neuromodulatory effect upon motor cortex.