Neural oscillations play a crucial role in communication between remote brain areas. Transcranial electric stimulation with alternating currents (TACS) can manipulate these brain oscillations in a non-invasive manner. Recently, TACS using multiple electrodes with phase shifted stimulation currents were developed to alter long-range connectivity. Typically, an increase in coordination between two areas is assumed when they experience an in-phase stimulation and a disorganization through an anti-phase stimulation. However, the underlying biophysics of multi-electrode TACS has not been studied in detail. Here, we leverage direct invasive recordings from two non-human primates during multi-electrode TACS to characterize electric field magnitude and phase as a function of the phase of stimulation currents. Further, we report a novel “traveling wave” stimulation where the location of the electric field maximum changes over the stimulation cycle. Our results provide a mechanistic understanding of the biophysics of multi-electrode TACS and enable future developments of novel stimulation protocols.
Bibliographical noteFunding Information:
Research reported in this publication was supported by NIH (R21 MH110217-01, R01 MH111439-01, and P50 MH109429) and the University of Minnesota’s MnDRIVE Initiative. We thank Stan Colcombe, Raj Sangoi, and Caixia Hu for MR imaging support and we thank Deborah Ross, Mark Klinger, Kathleen Shannon, and Tammy McGinnis for veterinary assistance.
© 2019, The Author(s).
PubMed: MeSH publication types
- Journal Article
- Research Support, N.I.H., Extramural
- Research Support, Non-U.S. Gov't