title: The COMT Val/Met polymorphism modulates effects of tDCS on response inhibition.
abstract: BACKGROUND
  Transcranial direct current stimulation (tDCS) is increasingly discussed as a new option to support the cognitive rehabilitation in neuropsychiatric disorders. However, the therapeutic impact of tDCS is limited by high inter-individual variability. Genetic factors most likely contribute to this variability by modulating the effects of tDCS.
  
  
  OBJECTIVE
  We aimed to investigate the influence of the COMT Val(108/158)Met polymorphism on cathodal tDCS effects on executive functioning.
  
  
  METHODS
  Cathodal tDCS was applied to the left dorsolateral prefrontal cortex (dlPFC) during the performance of a parametric Go/No-Go test.
  
  
  RESULTS
  We demonstrate an impairing effect of cathodal tDCS to the dlPFC on response inhibition. This effect was only found in individuals homozygous for the Val-allele of the COMT Val(108/158)Met polymorphism. No effects of stimulation on executive functions in Met-allele carriers were detected.
  
  
  CONCLUSIONS
  Our data indicate that i) cathodal, excitability reducing tDCS, interferes with inhibitory cognitive control, ii) the left dlPFC is critically involved in the neuronal network underlying the control of response inhibition, and iii) the COMT Val(108/158)Met polymorphism modulates the impact of cathodal tDCS on inhibitory control. Together with our previous finding that anodal tDCS selectively impairs set-shifting abilities in COMT Met/Met homozygous individuals, these results indicate that genetic factors modulate effects of tDCS on cognitive performance. Therefore, future tDCS research should account for genetic variability in the design and analysis of neurocognitive as well as therapeutic applications to reduce the variability of results and facilitate individualized neurostimulation approaches.
authors.affiliation: Department of Psychiatry and Psychotherapy, University of Tübingen, Calwerstrasse 14, 72076 Tübingen, Germany.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Nieratschker
authors.affiliation: Department of Psychiatry and Psychotherapy, University of Tübingen, Calwerstrasse 14, 72076 Tübingen, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Kiefer
authors.affiliation: Department of Psychosomatic Medicine and Psychotherapy, University of Tübingen, Osianderstrasse 5, 72076 Tübingen, Germany.
authors.forename: Katrin
authors.initials: K
authors.lastname: Giel
authors.affiliation: Clinical and Experimental Neuroscience, Luxembourg Centre for Systems Biomedicine, University of Luxembourg and Centre Hospitalier de Luxembourg, Campus Belval, 7, Avenue des Hauts-Forneaux, L-4362 Esch- sur-Alzette, Luxembourg; Department of Neurodegenerative Diseases, Hertie Institute for Clinical Brain Research, German Center for Neurodegenerative Diseases, University of Tübingen, Hoppe-Seyler-Straße 3, 72076 Tübingen, Germany.
authors.forename: Rejko
authors.initials: R
authors.lastname: Krüger
authors.affiliation: Department of Psychiatry and Psychotherapy, University of Tübingen, Calwerstrasse 14, 72076 Tübingen, Germany. Electronic address: christian.plewnia@uni-tuebingen.de.
authors.forename: Christian
authors.initials: C
authors.lastname: Plewnia
mesh_terms: D001288:Attention / Q000502:physiology; D002394:Catechol O-Methyltransferase / Q000235:genetics*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D056344:Executive Function / Q000502:physiology; D005260:Female; D005838:Genotype; D006801:Humans; D007266:Inhibition, Psychological; D008297:Male; D009433:Neural Inhibition / Q000502:physiology*; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D017397:Prefrontal Cortex / Q000502:physiology*; D065908:Transcranial Direct Current Stimulation; D055815:Young Adult
chemical_list: D002394:Catechol O-Methyltransferase
keywords: Brain stimulation; COMT; Catechol-O-methyltransferase; Dopamine; Genetics; Response inhibition