title: Cerebellar transcranial direct current stimulation modulates verbal working memory.
abstract: BACKGROUND
  Neuroimaging studies show cerebellar activations in a wide range of cognitive tasks and patients with cerebellar lesions often present cognitive deficits suggesting a cerebellar role in higher-order cognition.
  
  
  OBJECTIVE
  We used cathodal transcranial direct current stimulation (tDCS), known to inhibit neuronal excitability, over the cerebellum to investigate if cathodal tDCS impairs verbal working memory, an important higher-order cognitive faculty.
  
  
  METHODS
  We tested verbal working memory as measured by forward and backward digit spans in 40 healthy young participants before and after applying cathodal tDCS (2 mA, stimulation duration 25 min) to the right cerebellum using a randomized, sham-controlled, double-blind, cross-over design. In addition, we tested the effect of cerebellar tDCS on word reading, finger tapping and a visually cued sensorimotor task.
  
  
  RESULTS
  In line with lower digit spans in patients with cerebellar lesions, cerebellar tDCS reduced forward digit spans and blocked the practice dependent increase in backward digit spans. No effects of tDCS on word reading, finger tapping or the visually cued sensorimotor task were found.
  
  
  CONCLUSIONS
  Our results support the view that the cerebellum contributes to verbal working memory as measured by forward and backward digit spans. Moreover, the induction of reversible "virtual cerebellar lesions" in healthy individuals by means of tDCS may improve our understanding of the mechanistic basis of verbal working memory deficits in patients with cerebellar lesions.
authors.affiliation: Dept. of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany. post@andreas-boehringer.de
authors.forename: Andreas
authors.initials: A
authors.lastname: Boehringer
authors.forename: Katja
authors.initials: K
authors.lastname: Macher
authors.forename: Juergen
authors.initials: J
authors.lastname: Dukart
authors.forename: Arno
authors.initials: A
authors.lastname: Villringer
authors.forename: Burkhard
authors.initials: B
authors.lastname: Pleger
mesh_terms: D000328:Adult; D002531:Cerebellum / Q000502:physiology*; D004311:Double-Blind Method; D004558:Electric Stimulation / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D009483:Neuropsychological Tests; D017397:Prefrontal Cortex / Q000502:physiology
keywords: Cerebellum; Digit span; Working memory; tDCS