Original Research ARTICLE
EEG alpha activity reflects motor preparation rather than the mode of action selection
- 1INSERM U1039, Faculty of Medicine, La Tronche, France
- 2Clinical Neurophysiology and Neuroimaging Unit, Department of Psychiatry, University Hospitals of Geneva, Chêne-Bourg, Geneva, Switzerland
- 3GRISSUL, University of Lausanne, Lausanne, Switzerland
- 4FPSE, University of Geneva, Geneva, Switzerland
- 5CIG, University of Geneva, Geneva, Switzerland
Alpha-band activity (8–13 Hz) is not only suppressed by sensory stimulation and movements, but also modulated by attention, working memory and mental tasks, and could be sensitive to higher motor control functions. The aim of the present study was to examine alpha oscillatory activity during the preparation of simple left or right finger movements, contrasting the external and internal mode of action selection. Three preparation conditions were examined using a precueing paradigm with S1 as the preparatory and S2 as the imperative cue: Full, laterality instructed by S1; Free, laterality freely selected and None, laterality instructed by S2. Time-frequency (TF) analysis was performed in the alpha frequency range during the S1–S2 interval, and alpha motor-related amplitude asymmetries (MRAA) were also calculated. The significant MRAA during the Full and Free conditions indicated effective external and internal motor response preparation. In the absence of specific motor preparation (None), a posterior alpha event-related desynchronization (ERD) dominated, reflecting the main engagement of attentional resources. In Full and Free motor preparation, posterior alpha ERD was accompanied by a midparietal alpha event-related synchronization (ERS), suggesting a concomitant inhibition of task-irrelevant visual activity. In both Full and Free motor preparation, analysis of alpha power according to MRAA amplitude revealed two types of functional activation patterns: (1) a motor alpha pattern, with predominantly midparietal alpha ERS and large MRAA corresponding to lateralized motor activation/visual inhibition and (2) an attentional alpha pattern, with dominating right posterior alpha ERD and small MRAA reflecting visuospatial attention. The present results suggest that alpha oscillatory patterns do not resolve the selection mode of action, but rather distinguish separate functional strategies of motor preparation.
Keywords: motor preparation, motor selection, externally-cued action, internally-cued action, alpha-band activity, motor-related amplitude asymmetry
Citation: Deiber M-P, Sallard E, Ludwig C, Ghezzi C, Barral J and Ibañez V (2012) EEG alpha activity reflects motor preparation rather than the mode of action selection. Front. Integr. Neurosci. 6:59. doi: 10.3389/fnint.2012.00059
Received: 18 May 2012; Accepted: 26 July 2012;
Published online: 14 August 2012.
Edited by:Jose L. Perez Velazquez, Hospital for Sick Children and University of Toronto, Canada
Reviewed by:Gidon Felsen, University of Colorado Medical School, USA
David I. Shore, McMaster University, Canada
Copyright © 2012 Deiber, Sallard, Ludwig, Ghezzi, Barral and Ibañez. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in other forums, provided the original authors and source are credited and subject to any copyright notices concerning any third-party graphics etc.
*Correspondence: Marie-Pierre Deiber, Clinical Neurophysiology and Neuroimaging Unit, Department of Psychiatry, University Hospitals of Geneva, Chemin du Petit-Bel-Air 2, 1225 Chêne-Bourg, Geneva, Switzerland. e-mail: email@example.com