Multi-locus transcranial magnetic stimulation system for electronically targeted brain stimulation

Show full item record



Nieminen , J O , Sinisalo , H , Souza , V H , Malmi , M , Yuryev , M , Tervo , A E , Stenroos , M , Milardovich , D , Korhonen , J T , Koponen , L M & Ilmoniemi , R J 2022 , ' Multi-locus transcranial magnetic stimulation system for electronically targeted brain stimulation ' , Brain Stimulation , vol. 15 , no. 1 , pp. 116-124 .

Title: Multi-locus transcranial magnetic stimulation system for electronically targeted brain stimulation
Author: Nieminen, Jaakko O.; Sinisalo, Heikki; Souza, Victor H.; Malmi, Mikko; Yuryev, Mikhail; Tervo, Aino E.; Stenroos, Matti; Milardovich, Diego; Korhonen, Juuso T.; Koponen, Lari M.; Ilmoniemi, Risto J.
Contributor organization: HUS Medical Imaging Center
BioMag Laboratory
Date: 2022
Language: eng
Number of pages: 9
Belongs to series: Brain Stimulation
ISSN: 1935-861X
Abstract: Background: Transcranial magnetic stimulation (TMS) allows non-invasive stimulation of the cortex. In multi-locus TMS (mTMS), the stimulating electric field (E-field) is controlled electronically without coil movement by adjusting currents in the coils of a transducer. Objective: To develop an mTMS system that allows adjusting the location and orientation of the E-field maximum within a cortical region. Methods: We designed and manufactured a planar 5-coil mTMS transducer to allow controlling the maximum of the induced E-field within a cortical region approximately 30 mm in diameter. We developed electronics with a design consisting of independently controlled H-bridge circuits to drive up to six TMS coils. To control the hardware, we programmed software that runs on a field-programmable gate array and a computer. To induce the desired E-field in the cortex, we developed an optimization method to calculate the currents needed in the coils. We characterized the mTMS system and conducted a proof-of-concept motor-mapping experiment on a healthy volunteer. In the motor mapping, we kept the transducer placement fixed while electronically shifting the E-field maximum on the precentral gyrus and measuring electromyography from the contralateral hand. Results: The transducer consists of an oval coil, two figure-of-eight coils, and two four-leaf-clover coils stacked on top of each other. The technical characterization indicated that the mTMS system performs as designed. The measured motor evoked potential amplitudes varied consistently as a function of the location of the E-field maximum. Conclusion: The developed mTMS system enables electronically targeted brain stimulation within a cortical region. (c) 2021 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license (
Subject: Transcranial magnetic stimulation
Electric field
Motor mapping
3112 Neurosciences
3124 Neurology and psychiatry
Peer reviewed: Yes
Rights: cc_by_nc_nd
Usage restriction: openAccess
Self-archived version: publishedVersion

Files in this item

Total number of downloads: Loading...

Files Size Format View
PIIS1935861X21008299.pdf 1.803Mb PDF View/Open

This item appears in the following Collection(s)

Show full item record