title: The role of the cerebellum in motor imagery.
abstract: OBJECTIVE
  Although it is well documented that the cerebellum plays a role in motor imagery (MI), its exact role in MI is still obscure. Since motor imagery and execution of movement share common pathways, and the cerebellum has an inhibitory effect on the motor cortex, we speculated that the cerebellum also has an inhibitory role on MI.
  
  
  METHODS
  To test this hypothesis, 12 healthy individuals aged 27-47 years (mean age 33.3 years) were enrolled in the study. Subjects were asked to imagine two different tasks, one complex (MI-c) and one simple (MI-s) motor task. The intensity of anodal cerebellar transcranial direct current stimulation (ctDCS) was set at 2 mA for 20 min. Sham ctDCS consisted of 30s current stimulation.
  
  
  RESULTS
  MI-s resulted in significantly increased log MEP amplitude during MI, compared with control MEP amplitude,(p=0.000). The increase in log MEP amplitude during MI disappeared after anodal ctDCS. Before sham ctDCS, both MI-s and MI-c resulted in log MEP amplitude increases (p=0.000). This facilitator effect of both MI-c and MI-s on log MEP amplitude was also persistent after sham ctDCS (p=0.000).
  
  
  CONCLUSIONS
  The study demonstrates for the first time that the cerebellum has an inhibitory effect on MI.
  
  
  CONCLUSIONS
  Combining ctDCS with MI significantly modulates corticomotor excitability.
authors.affiliation: Motor Control Laboratory, The Clinical Neurophysiology Division of the Department of Neurology, Gazi University Faculty of Medicine, Ankara, Turkey. Electronic address: bcengiz@gazi.edu.tr.
authors.forename: Bülent
authors.initials: B
authors.lastname: Cengiz
authors.affiliation: Motor Control Laboratory, The Clinical Neurophysiology Division of the Department of Neurology, Gazi University Faculty of Medicine, Ankara, Turkey.
authors.forename: H Evren
authors.initials: HE
authors.lastname: Boran
mesh_terms: D000328:Adult; D002531:Cerebellum / Q000502:physiology*; D005260:Female; D006801:Humans; D007092:Imagination / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000502:physiology; D009068:Movement; D065908:Transcranial Direct Current Stimulation; D050781:Transcranial Magnetic Stimulation
keywords: Cerebellar excitability; Cerebellar transcranial direct current stimulation; Motor excitability; Motor imagery