Low-frequency alternating current stimulation rhythmically suppresses gamma-band oscillations and impairs perceptual performance

Neuroimage. 2019 Jan 1:184:440-449. doi: 10.1016/j.neuroimage.2018.09.047. Epub 2018 Sep 19.


Low frequency oscillations such as alpha (8-12 Hz) are hypothesized to rhythmically gate sensory processing, reflected by 40-100 Hz gamma band activity, via the mechanism of pulsed inhibition. We applied transcranial alternating current stimulation (TACS) at individual alpha frequency (IAF) and flanking frequencies (IAF-4 Hz, IAF+4 Hz) to the occipital cortex of healthy human volunteers during concurrent magnetoencephalography (MEG), while participants performed a visual detection task inducing strong gamma-band responses. Occipital (but not retinal) TACS phasically suppressed stimulus-induced gamma oscillations in the visual cortex and impaired target detection, with stronger phase-to-amplitude coupling predicting behavioral impairments. Retinal control TACS ruled out retino-thalamo-cortical entrainment resulting from (subthreshold) retinal stimulation. All TACS frequencies tested were effective, suggesting that visual gamma-band responses can be modulated by a range of low frequency oscillations. We propose that TACS-induced membrane potential modulations mimic the rhythmic change in cortical excitability by which spontaneous low frequency oscillations may eventually exert their impact when gating sensory processing via pulsed inhibition.

Keywords: Alpha; Gamma; Phase-amplitude coupling (PAC); TACS-MEG; Visual cortex; Visual detection.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Female
  • Gamma Rhythm / physiology*
  • Humans
  • Magnetoencephalography* / methods
  • Male
  • Transcranial Direct Current Stimulation* / methods
  • Visual Cortex / physiology*
  • Visual Perception / physiology*
  • Young Adult