title: Electroencephalographic effects of transcranial random noise stimulation in the auditory cortex.
abstract: BACKGROUND
  Transcranial random noise stimulation (tRNS) is an innovative technique of non-invasive electrical stimulation. tRNS over the parietal cortex has improved cognitive function in healthy controls and, applied to the auditory cortex, tRNS has shown beneficial effects on tinnitus.
  
  
  OBJECTIVE
  Here we aimed to investigate the effects of tRNS over the auditory cortex on resting state and evoked activity in healthy subjects.
  
  
  METHODS
  We used EEG to measure tRNS induced changes in resting state activity and in auditory steady state responses (ASSRs). Stimuli were 1000 Hz carrier frequency tones, amplitude modulated at 20 Hz and 40 Hz and applied in randomized order. Fourteen subjects participated in a placebo-controlled randomized design study; each received 20 min of tRNS applied over auditory cortices with 2 mA, with a one week interval between real and sham stimulation.
  
  
  RESULTS
  We found a significant increase in the ASSR in response to 40 Hz frequency modulated tone and a non-significant trend toward an increase in mean theta band power and variability of the theta band power for the resting state data.
  
  
  CONCLUSIONS
  Our finding of tRNS induced increased excitability in the auditory cortex parallels previous findings of tRNS effects on motor cortex excitability and is in line with current concepts of tRNS mechanisms such as increase of stochastic resonance.
authors.affiliation: Department of Psychiatry and Psychotherapy, University of Regensburg, Germany; Experimental and Clinical Neuroscience, University of Regensburg, Elite Network Bavaria, Germany.
authors.forename: Jessica
authors.initials: J
authors.lastname: Van Doren
authors.affiliation: Department of Psychiatry and Psychotherapy, University of Regensburg, Germany.
authors.forename: Berthold
authors.initials: B
authors.lastname: Langguth
authors.affiliation: Department of Psychiatry and Psychotherapy, University of Regensburg, Germany. Electronic address: martin.schecklmann@medbo.de.
authors.forename: Martin
authors.initials: M
authors.lastname: Schecklmann
mesh_terms: D000328:Adult; D001303:Auditory Cortex / Q000502:physiology*; D058256:Brain Waves / Q000502:physiology*; D004569:Electroencephalography; D005260:Female; D006801:Humans; D008297:Male; D012146:Rest / Q000502:physiology; D065908:Transcranial Direct Current Stimulation / Q000009:adverse effects*; D055815:Young Adult
keywords: Auditory cortex; Auditory steady state response; Transcranial random noise stimulation; tRNS