title: Effects of High-Definition and Conventional tDCS on Response Inhibition.
abstract: Response inhibition is a critical executive function, enabling the adaptive control of behavior in a changing environment. The inferior frontal cortex (IFC) is considered to be critical for response inhibition, leading researchers to develop transcranial direct current stimulation (tDCS) montages attempting to target the IFC and improve inhibitory performance. However, conventional tDCS montages produce diffuse current through the brain, making it difficult to establish causality between stimulation of any one given brain region and resulting behavioral changes. Recently, high-definition tDCS (HD-tDCS) methods have been developed to target brain regions with increased focality relative to conventional tDCS.
  
  
  
  Remarkably few studies have utilized HD-tDCS to improve cognitive task performance, however, and no study has directly compared the behavioral effects of HD-tDCS to conventional tDCS.
  
  
  
  In the present study, participants received either HD-tDCS or conventional tDCS to the IFC during performance of a response inhibition task (stop-signal task, SST) or a control task (choice reaction time task, CRT). A third group of participants completed the same behavioral protocols, but received tDCS to a control site (mid-occipital cortex). Post-stimulation improvement in SST performance was analyzed as a function of tDCS group and the task performed during stimulation using both conventional and Bayesian parameter estimation analyses.
  
  
  
  Bayesian estimation of the effects of HD- and conventional tDCS to IFC relative to control site stimulation demonstrated enhanced response inhibition for both conditions. No improvements were found after control task (CRT) training in any tDCS condition.
  
  
  
  Results support the use of both HD- and conventional tDCS to the IFC for improving response inhibition, providing empirical evidence that HD-tDCS can be used to facilitate performance on an executive function task.
authors.affiliation: Cognitive Neuroscience Laboratory, Rehabilitation Institute of Chicago, Chicago, IL, USA; Department of Physical Medicine and Rehabilitation, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA. Electronic address: jeremy.hogeveen@northwestern.edu.
authors.forename: J
authors.initials: J
authors.lastname: Hogeveen
authors.affiliation: Cognitive Neuroscience Laboratory, Rehabilitation Institute of Chicago, Chicago, IL, USA; Department of Physical Medicine and Rehabilitation, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA; Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
authors.forename: J
authors.initials: J
authors.lastname: Grafman
authors.affiliation: Department of Biomedical Engineering, The City College of New York, New York, NY, USA.
authors.forename: M
authors.initials: M
authors.lastname: Aboseria
authors.affiliation: Department of Biomedical Engineering, The City College of New York, New York, NY, USA.
authors.forename: A
authors.initials: A
authors.lastname: David
authors.affiliation: Department of Biomedical Engineering, The City College of New York, New York, NY, USA.
authors.forename: M
authors.initials: M
authors.lastname: Bikson
authors.affiliation: Cognitive Neuroscience Laboratory, Rehabilitation Institute of Chicago, Chicago, IL, USA; Department of Physical Medicine and Rehabilitation, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA; Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
authors.forename: K K
authors.initials: KK
authors.lastname: Hauner
mesh_terms: D001499:Bayes Theorem; D056344:Executive Function / Q000502:physiology*; D005260:Female; D005625:Frontal Lobe / Q000502:physiology*; D006801:Humans; D007266:Inhibition, Psychological; D008297:Male; D009483:Neuropsychological Tests; D011930:Reaction Time / Q000502:physiology; D065908:Transcranial Direct Current Stimulation / Q000379:methods*
keywords: Computational neurostimulation; HD-tDCS; Inferior frontal cortex; Response inhibition; Transcranial direct current stimulation