No effects of transcranial direct current stimulation on visual evoked potential and peak gamma frequency

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Dawood A. B., Dickinson A., AYTEMÜR A., Milne E., Jones M.

Cognitive Processing, vol.23, no.2, pp.235-254, 2022 (SSCI, Scopus) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 23 Issue: 2
  • Publication Date: 2022
  • Doi Number: 10.1007/s10339-022-01076-3
  • Journal Name: Cognitive Processing
  • Journal Indexes: Social Sciences Citation Index (SSCI), Scopus, PASCAL, EMBASE, Linguistics & Language Behavior Abstracts, MEDLINE, Psycinfo
  • Page Numbers: pp.235-254
  • Keywords: Excitation-inhibition balance, Neuromodulation, tDCS, EEG, Visual evoked potential, Peak gamma frequency
  • Open Archive Collection: AVESIS Open Access Collection
  • Manisa Celal Bayar University Affiliated: Yes

Abstract

Evidence suggests that the visual evoked potential (VEP) and gamma oscillations elicited by visual stimuli reflect the balance of excitatory and inhibitory (E-I) cortical processes. As tDCS has been shown to modulate E–I balance, the current study investigated whether amplitudes of VEP components (N1 and P2) and peak gamma frequency are modulated by transcranial direct current stimulation (tDCS). Healthy adults underwent two electroencephalography (EEG) recordings while viewing stimuli designed to elicit a robust visual response. Between the two recordings, participants were randomly assigned to three tDCS conditions (anodal-, cathodal-, and sham-tDCS) or received no-tDCS. tDCS electrodes were placed over the occipital cortex (Oz) and the left cheek with an intensity of 2 mA for 10 min. Data of 39 participants were analysed for VEP amplitudes and peak gamma frequency using mixed-model ANOVAs. The results showed no main effects of tDCS in any metric. Possible explanations for the absence of tDCS effects are discussed.