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Neural Plasticity
Volume 2014, Article ID 210396, 8 pages
http://dx.doi.org/10.1155/2014/210396
Clinical Study

Modulation of Cortical Interhemispheric Interactions by Motor Facilitation or Restraint

1University of Lisbon, Faculty of Human Kinetics, CIPER, LBMF, 1499-002 Lisbon, Portugal
2Garcia de Orta Hospital, Pragal, 2801-951 Almada, Portugal
3Visual Neuroscience Laboratory, Institute for Biomedical Imaging in Life Sciences (IBILI), ICNAS, Faculty of Medicine, University of Coimbra, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal
4Stroke Unit, Department of Neurology, Coimbra University Hospital, 3000-075 Coimbra, Portugal

Received 1 December 2013; Accepted 13 January 2014; Published 24 February 2014

Academic Editor: Michel Baudry

Copyright © 2014 Ana Cristina Vidal et al. 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

Cortical interhemispheric interactions in motor control are still poorly understood and it is important to clarify how these depend on inhibitory/facilitatory limb movements and motor expertise, as reflected by limb dominance. Here we addressed this problem using functional magnetic resonance imaging (fMRI) and a task involving dominant/nondominant limb mobilization in the presence/absence of contralateral limb restraint. In this way we could modulate excitation/deactivation of the contralateral hemisphere. Blocks of arm elevation were alternated with absent/present restraint of the contralateral limb in 17 participants. We found the expected activation of contralateral sensorimotor cortex and ipsilateral cerebellum during arm elevation. In addition, only the dominant arm elevation (hold period) was accompanied by deactivation of ipsilateral sensorimotor cortex, irrespective of presence/absence of contralateral restraint, although the latter increased deactivation. In contrast, the nondominant limb yielded absent deactivation and reduced area of contralateral activation upon restriction. Our results provide evidence for a difference in cortical communication during motor control (action facilitation/inhibition), depending on the “expertise” of the hemisphere that controls action (dominant versus nondominant). These results have relevant implications for the development of facilitation/inhibition strategies in neurorehabilitation, namely, in stroke, given that fMRI deactivations have recently been shown to reflect decreases in neural responses.