Transcranial current stimulation (tCS) has been widely used to noninvasively investigate and influence brain function in both healthy volunteers and clinical populations. While many positive effects have been found, the goals of high focality, accurate targeting and deep stimulation are yet to be achieved. Transcranial temporal interference stimulation (TIS) is a new form of tCS that might improve it on all three fronts. TIS uses two alternating currents to create an amplitude-modulated electric field that can peak deep in the brain. Initial murine and human studies showed promising effects of TIS, but knowledge about working mechanisms and optimal application is still limited. In this talk I will present results of finite element simulations with realistic head models to investigate the electric fields induced by TIS in the brain, comparing results in murine and human head models for TIS and conventional tCS. Due to the nonlinear nature of TIS, conventional methods to optimize tCS fields for a specific brain target cannot be used. I will present various novel optimization methods for TIS and compare their efficiency and results. Finally, I will discuss the implications of the results of these simulation and optimization studies for potential applications of TIS in humans.

Sumientra Rampersad is an Assistant Professor of Physics at the University of Massachusetts, and a Research Assistant Professor of Physical Therapy, Movement and Rehabilitation Sciences at Northeastern University, both located in Boston, USA. Her lab studies various brain stimulation modalities (e.g., tCS, TMS, sEEG) through a combination of computational modeling and experiments, aiming to better understand the working mechanisms and improve the application of these methods. She recently received a large grant from the National Institutes of Health to investigate and improve TIS through modeling and optimization, and primate and human experiments.