Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10215599 | NeuroImage | 2019 | 33 Pages |
Abstract
Low frequency oscillations such as alpha (8-12Â Hz) are hypothesized to rhythmically gate sensory processing, reflected by 40-100Â 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+4Â 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.
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Authors
Jim D. Herring, Sophie Esterer, Tom R. Marshall, Ole Jensen, Til O. Bergmann,