title: Importance of baseline in event-related desynchronization during a combination task of motor imagery and motor observation.
abstract: OBJECTIVE
  Event-related desynchronization (ERD) or synchronization (ERS) refers to the modulation of any EEG rhythm in response to a particular event. It is typically quantified as the ratio between a baseline and a task condition (the event). Here, we focused on the sensorimotor mu-rhythm. We explored the effects of different baselines on mu-power and ERD of the mu-rhythm during a motor imagery task.
  
  
  METHODS
  Eighteen healthy subjects performed motor imagery tasks while EEGs were recorded. Five different baseline movies were shown. For the imagery task a right-hand opening/closing movie was shown. Power and ERD of the mu-rhythm recorded over C3 and C4 for the different baselines were estimated.
  
  
  RESULTS
  50% of the subjects showed relatively high mu-power for specific baselines only, and ERDs of these subjects were strongly dependent on the baseline used. In 17% of the subjects no preference was found. Contralateral ERD of the mu-rhythm was found in about 67% of the healthy volunteers, with a significant baseline preference in about 75% of that subgroup.
  
  
  CONCLUSIONS
  The sensorimotor ERD quantifies activity of the brain during motor imagery tasks. Selection of the optimal baseline increases ERD.
authors: Neural Engineering Department, Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede, The Netherlands. c.tangwiriyasakul@utwente.nl
authors: Chayanin
authors: C
authors: Tangwiriyasakul
authors: Rens
authors: R
authors: Verhagen
authors: Michel J A M
authors: MJ
authors: van Putten
authors: Wim L C
authors: WL
authors: Rutten
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D004569:Electroencephalography; D058407:Electroencephalography Phase Synchronization; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006225:Hand / Q000502:physiology; D006801:Humans; D007092:Imagination / Q000502:physiology*; D008297:Male; D009068:Movement / Q000502:physiology*; D055815:Young Adult