RT Journal Article
SR Electronic
T1 Electric Field Dynamics in the Brain During Multi-Electrode Transcranial Electric Stimulation
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 340224
DO 10.1101/340224
A1 Alekseichuk, Ivan
A1 Falchier, Arnaud Y.
A1 Linn, Gary
A1 Xu, Ting
A1 Milham, Michael P.
A1 Schroeder, Charles E.
A1 Opitz, Alexander
YR 2018
UL http://biorxiv.org/content/early/2018/06/06/340224.abstract
AB 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. Of particular interest, TACS protocols using multiple electrodes with phase shifted stimulation currents were developed to alter the connectivity between two or more brain regions. Typically, an increase in coordination between two sites 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, thus limiting our ability to develop a mechanistic understanding. Here, we leverage direct invasive recordings from two non-human primates during multi-electrode TACS to show that the electric field magnitude and phase depend on the phase of the stimulation currents in a non-linear manner. Further, we report a novel phenomenon of a “traveling wave” stimulation where the location of the electric field maximum changes over the stimulation cycle. Our results provide a basis for a mechanistic understanding of multi-electrode TACS, necessitating the reevaluation of previously published studies, and enable future developments of novel stimulation protocols.