Magnetically Induced Temporal Interference for Focal and Deep-Brain Stimulation

Zonghao Xin; Akihiro Kuwahata; Shuang Liu; Masaki Sekino

doi:10.3389/fnhum.2021.693207

Magnetically Induced Temporal Interference for Focal and Deep-Brain Stimulation

Front Hum Neurosci. 2021 Sep 27:15:693207. doi: 10.3389/fnhum.2021.693207. eCollection 2021.

Authors

Zonghao Xin¹, Akihiro Kuwahata², Shuang Liu², Masaki Sekino¹

Affiliations

¹ Laboratory Sekino, Department of Bioengineering, School of Engineering, The University of Tokyo, Tokyo, Japan.
² Laboratory Sekino, Department of Electrical Engineering and Information Systems, Graduate School of Engineering, The University of Tokyo, Tokyo, Japan.

Abstract

Transcranial magnetic stimulation (TMS) is a non-invasive brain stimulation technique that has been clinically applied for neural modulation. Conventional TMS systems are restricted by the trade-off between depth penetration and the focality of the induced electric field. In this study, we integrated the concept of temporal interference (TI) stimulation, which has been demonstrated as a non-invasive deep-brain stimulation method, with magnetic stimulation in a four-coil configuration. The attenuation depth and spread of the electric field were obtained by performing numerical simulation. Consequently, the proposed temporally interfered magnetic stimulation scheme was demonstrated to be capable of stimulating deeper regions of the brain model while maintaining a relatively narrow spread of the electric field, in comparison to conventional TMS systems. These results demonstrate that TI magnetic stimulation could be a potential candidate to recruit brain regions underneath the cortex. Additionally, by controlling the geometry of the coil array, an analogous relationship between the field depth and focality was observed, in the case of the newly proposed method. The major limitations of the methods, however, would be the considerable intensity and frequency of the input current, followed by the frustration in the thermal management of the hardware.

Keywords: coil array; depth-focality trade-off; temporal interference magnetic stimulation; temporal interference stimulation; transcranial magnetic stimulation.