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bioRxiv · 10.1101/2020.11.16.382267

Bifocal tACS Enhances Visual Motion Discrimination by Modulating Phase Amplitude Coupling Between V1 and V5 Regions

Salamanca, R.·Raffin, E.·Zandvliet, S.·Seeber, M.·Michel, C.·Sauseng, P.·Huxlin, K. R.·Hummel, F.
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Abstract

Visual motion discrimination involves reciprocal interactions in the alpha band between the primary visual cortex (V1) and the mediotemporal area (V5/MT). We investigated whether modulating alpha phase synchronization using individualized multisite transcranial alternating current stimulation (tACS) over V5 and V1 regions would improve motion discrimination. We tested 3 groups of healthy subjects: 1) an individualized In-Phase V1alpha-V5alpha tACS (0{degrees} lag) group, 2) an individualized Anti-Phase V1alpha-V5alpha tACS (180{degrees} lag) group and 3) a sham tACS group. Motion discrimination and EEG activity were compared before, during and after tACS. Performance significantly improved in the Anti-Phase group compared to that in the In-Phase group at 10 and 30 minutes after stimulation. This result could be explained by changes in bottom-up alpha-V1 gamma-V5 phase-amplitude coupling. Thus, Anti-Phase V1alpha-V5alpha tACS might impose an optimal phase lag between stimulation sites due to the inherent speed of wave propagation, hereby supporting optimized neuronal communication. IMPACT STATEMENTO_LIAlpha multisite (V1 and V5) tACS influences global motion discrimination and integration C_LIO_LIPhase-amplitude coupling is associated with visual performance C_LIO_LIMultisite Anti-Phase stimulation of strategic visual areas (V1 and V5) is associated with connectivity changes in the visual cortex and thus, associated with changes in direction acuity C_LI

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Salamanca, R., Raffin, E., Zandvliet, S., Seeber, M., Michel, C., Sauseng, P., Huxlin, K. R., Hummel, F.. 2020-11-17. Bifocal tACS Enhances Visual Motion Discrimination by Modulating Phase Amplitude Coupling Between V1 and V5 Regions. https://doi.org/10.1101/2020.11.16.382267

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