In-vivo Imaging of Magnetic Fields Induced by Transcranial Direct Current Stimulation (tDCS) in Human Brain using MRI

Authors

Mayank V. Jog, University of California, Los Angeles
Robert X. Smith, University of California, Los Angeles
Kay Jann, University of California, Los Angeles
Walter Dunn, University of California, Los Angeles
Belen Lafon, CUNY City College
Dennis Truong, CUNY City College
Allan Wu, University of California, Los Angeles
Lucas C. Parra, CUNY City CollegeFollow
Marom Bikson, CUNY City CollegeFollow
Danny J. J. Wang, University of California, Los Angeles

Document Type

Article

Publication Date

10-6-2016

Abstract

Transcranial direct current stimulation (tDCS) is an emerging non-invasive neuromodulation technique that applies mA currents at the scalp to modulate cortical excitability. Here, we present a novel magnetic resonance imaging (MRI) technique, which detects magnetic fields induced by tDCS currents. This technique is based on Ampere’s law and exploits the linear relationship between direct current and induced magnetic fields. Following validation on a phantom with a known path of electric current and induced magnetic field, the proposed MRI technique was applied to a human limb (to demonstrate invivo feasibility using simple biological tissue) and human heads (to demonstrate feasibility in standard tDCS applications). The results show that the proposed technique detects tDCS induced magnetic fields as small as a nanotesla at millimeter spatial resolution. Through measurements of magnetic fields linearly proportional to the applied tDCS current, our approach opens a new avenue for direct in-vivo visualization of tDCS target engagement.

Comments

This article was originally published in Scientific Reports, available at DOI: 10.1038/srep34385.

This work is licensed under a Creative Commons Attribution 4.0 International License.