RT Journal Article
SR Electronic
T1 Phase-specific manipulation of neural oscillations by transcranial alternating current stimulation
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 579631
DO 10.1101/579631
A1 Marina Fiene
A1 Bettina C. Schwab
A1 Jonas Misselhorn
A1 Christoph S. Herrmann
A1 Till R. Schneider
A1 Andreas K. Engel
YR 2019
UL http://biorxiv.org/content/early/2019/07/18/579631.abstract
AB Oscillatory phase has been proposed as a key parameter defining the spatiotemporal structure of neural activity. To enhance our understanding of brain rhythms, phase-specific modulation of oscillations by transcranial alternating current stimulation (tACS) emerged as a promising approach. However, the effectiveness of tACS is still critically debated. Here, we investigated the phase-specificity of tACS effects on visually evoked steady state responses (SSRs). We observed that the phase shift between flicker and tACS modulates evoked SSR amplitudes. Neural sources of phase-specific effects were localized in the parieto-occipital cortex within flicker-aligned regions. Importantly, tACS effects were stronger in subjects with weaker locking of neural responses to flicker phase. Overall, our data provide evidence for a phase-specific modulation of oscillations by tACS, since SSR amplitude changes can only result from phase-dependent interactions with applied electric fields. This finding corroborates the physiological efficacy of tACS and highlights its potential for controlled modulations of brain signals.