title: Rhythmic gamma stimulation affects bistable perception.
abstract: When our brain is confronted with ambiguous visual stimuli, perception spontaneously alternates between different possible interpretations although the physical stimulus remains the same. Both alpha (8-12 Hz) and gamma (>30 Hz) oscillations have been reported to correlate with such spontaneous perceptual reversals. However, whether these oscillations play a causal role in triggering perceptual switches remains unknown. To address this question, we applied transcranial alternating current stimulation (tACS) over the posterior cortex of healthy human participants to boost alpha and gamma oscillations. At the same time, participants were reporting their percepts of an ambiguous structure-from-motion stimulus. We found that tACS in the gamma band (60 Hz) increased the number of spontaneous perceptual reversals, whereas no significant effect was found for tACS in alpha (10 Hz) and higher gamma (80 Hz) frequencies. Our results suggest a mechanistic role of gamma but not alpha oscillations in the resolution of perceptual ambiguity.
authors.affiliation: 1University of Goettingen.|2Leibniz Institute for Primate Research, Goettingen, Germany.
authors.forename: Yuranny
authors.initials: Y
authors.lastname: Cabral-Calderin
authors.affiliation: 1University of Goettingen.
authors.forename: Carsten
authors.initials: C
authors.lastname: Schmidt-Samoa
authors.affiliation: 1University of Goettingen.|2Leibniz Institute for Primate Research, Goettingen, Germany.|3DFG Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMBP).
authors.forename: Melanie
authors.initials: M
authors.lastname: Wilke
mesh_terms: D000328:Adult; D000513:Alpha Rhythm / Q000502:physiology; D002540:Cerebral Cortex / Q000502:physiology*; D004569:Electroencephalography; D005260:Female; D065818:Gamma Rhythm / Q000502:physiology*; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests; D010775:Photic Stimulation / Q000379:methods; D065908:Transcranial Direct Current Stimulation; D014796:Visual Perception / Q000502:physiology*