title: Cathodal stimulation of human MT+ leads to elevated fMRI signal: a tDCS-fMRI study.
abstract: OBJECTIVE
  Transcranial direct current stimulation (tDCS) was reintroduced about a decade ago as a tool for inducing long-lasting changes in cortical excitability. Recently it has been shown that both motor and cognitive functions can be influenced by tDCS. Here, we tested the effect of tDCS on the blood-oxygen level dependent (BOLD) signal evoked by coherent visual motion using functional magnetic resonance imaging (fMRI).
  
  
  METHODS
  The subjects underwent 10 min of cathodal and sham tDCS, applied over the right MT+. Following stimulation, random dot kinomatograms (RDK) with different percentages (10%, 30%, 50%) of coherently moving dots were presented.
  
  
  RESULTS
  All motion stimuli activated MT+ in both stimulation conditions. However, cathodal stimulation led to an increase in fMRI signal in MT+ when compared to sham stimulation. This effect did not depend on the coherence level of the visual stimulus.
  
  
  CONCLUSIONS
  Here, we show for the first time, that cathodal tDCS stimulation leads to elevated fMRI signal in the human visual cortex.
authors.affiliation: Department of Clinical Neurophysiology, University Medical Center, Georg-August University of Göttingen, Göttingen, Germany. Aantal@gwdg.de
authors.forename: Andrea
authors.initials: A
authors.lastname: Antal
authors.forename: Gyula
authors.initials: G
authors.lastname: Kovács
authors.forename: Leila
authors.initials: L
authors.lastname: Chaieb
authors.forename: Csaba
authors.initials: C
authors.lastname: Cziraki
authors.forename: Walter
authors.initials: W
authors.lastname: Paulus
authors.forename: Mark W
authors.initials: MW
authors.lastname: Greenlee
mesh_terms: D000328:Adult; D002560:Cerebrovascular Circulation / Q000502:physiology*; D004558:Electric Stimulation / Q000295:instrumentation / Q000379:methods*; D004566:Electrodes / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D009039:Motion Perception / Q000502:physiology*; D013702:Temporal Lobe / Q000502:physiology*; D014793:Visual Cortex / Q000502:physiology*; D055815:Young Adult