NeuroImage (Oct 2021)

Enhancing visual motion discrimination by desynchronizing bifocal oscillatory activity

  • Roberto F. SALAMANCA-GIRON,
  • Estelle RAFFIN,
  • Sarah B. ZANDVLIET,
  • Martin SEEBER,
  • Christoph M. MICHEL,
  • Paul SAUSENG,
  • Krystel R. HUXLIN,
  • Friedhelm C. HUMMEL

Journal volume & issue
Vol. 240
p. 118299

Abstract

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Visual motion discrimination involves reciprocal interactions in the alpha band between the primary visual cortex (V1) and mediotemporal areas (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 with the following conditions: (1) individualized In-Phase V1alpha-V5alpha tACS (0° lag), (2) individualized Anti-Phase V1alpha-V5alpha tACS (180° lag) and (3) sham tACS. Motion discrimination and EEG activity were recorded before, during and after tACS. Performance significantly improved in the Anti-Phase group compared to the In-Phase group 10 and 30 min after stimulation. This result was explained by decreases in bottom-up alpha-V1 gamma-V5 phase-amplitude coupling. One possible explanation of these results is that 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.

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