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Biomedical Engineering / Biomedizinische Technik

Joint Journal of the German Society for Biomedical Engineering in VDE and the Austrian and Swiss Societies for Biomedical Engineering and the German Society of Biomaterials

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Volume 63, Issue 6


Volume 57 (2012)

Effect of TMS coil orientation on the spatial distribution of motor evoked potentials in an intrinsic hand muscle

Victor Hugo SouzaORCID iD: http://orcid.org/0000-0002-0254-4322
  • Corresponding author
  • Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (FFCLRP), Universidade de São Paulo (USP), Av. Bandeirantes, 3900, 14040-901 Ribeirão Preto-SP, Brazil, Phone: +55 16 33153778, Fax: +55 16 33154887
  • orcid.org/0000-0002-0254-4322
  • Email
  • Other articles by this author:
  • De Gruyter OnlineGoogle Scholar
/ Taian Martins Vieira
  • Departamento de Arte Corporal, Escola de Educação Física e Desportos, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho, 540, 21941-599 Rio de Janeiro, RJ, Brazil
  • Laboratorio di Ingegneria del Sistema Neuromuscolare, Dipartimento di Elettronica e Telecomunicazioni, Politecnico di Torino, Via Cavalli 22/H, 10138 Turin, Italy
  • Other articles by this author:
  • De Gruyter OnlineGoogle Scholar
/ André Salles Cunha Peres
  • Instituto Internacional de Neurociência de Natal Edmond e Lily Safra, Instituto Santos Dumont, Rodovia RN 160 Km 03, 3003, 59280-000 Macaíba-RN, Brazil
  • Other articles by this author:
  • De Gruyter OnlineGoogle Scholar
/ Marco Antonio Cavalcanti GarciaORCID iD: http://orcid.org/0000-0002-8225-6573 / Claudia Domingues Vargas
  • Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho, 373, 21941-902 Rio de Janeiro-RJ, Brazil
  • Other articles by this author:
  • De Gruyter OnlineGoogle Scholar
/ Oswaldo Baffa
  • Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes, 3900, 14040-901 Ribeirão Preto, SP, Brazil
  • Other articles by this author:
  • De Gruyter OnlineGoogle Scholar
Published Online: 2017-08-10 | DOI: https://doi.org/10.1515/bmt-2016-0240


Previous reports on the relationship between coil orientation and amplitude of motor evoked potential (MEP) in transcranial magnetic stimulation (TMS) did not consider the effect of electrode arrangement. Here we explore this open issue by investigating whether TMS coil orientation affects the amplitude distribution of MEPs recorded from the abductor pollicis brevis (APB) muscle with a bi-dimensional grid of 61 electrodes. Moreover, we test whether conventional mono- and bipolar montages provide representative MEPs compared to those from the grid of electrodes. Our results show that MEPs with the greatest amplitudes were elicited for 45° and 90° coil orientations, i.e. perpendicular to the central sulcus, for all electrode montages. Stimulation with the coil oriented at 135° and 315°, i.e. parallel to the central sulcus, elicited the smallest MEP amplitudes. Additionally, changes in coil orientation did not affect the spatial distribution of MEPs over the muscle extent. It has been shown that conventional electrodes with detection volume encompassing the APB belly may detect representative MEPs for optimal coil orientations. In turn, non-optimal orientations were identified only with the grid of electrodes. High-density electromyography may therefore provide new insights into the effect of coil orientation on MEPs from the APB muscle.

Keywords: brain stimulation; conventional electrodes; electric field direction; high-density electromyography; muscle imaging; transcranial magnetic stimulation


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About the article

aTaian Martins Vieira and André Salles Cunha Peres: These authors contributed equally to this work

Received: 2016-08-24

Accepted: 2017-07-03

Published Online: 2017-08-10

Published in Print: 2018-11-27

Funding: VHS was a recipient of a scholarship provided by Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP; 2012/11937-0). This research has been conducted as part of the activities of FAPESP research, dissemination, and innovation center for Neuromathematics (grant 2013/07699-0). This work was also supported by Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES).

Conflict of interest statement: Authors state no conflict of interest.

Citation Information: Biomedical Engineering / Biomedizinische Technik, Volume 63, Issue 6, Pages 635–645, ISSN (Online) 1862-278X, ISSN (Print) 0013-5585, DOI: https://doi.org/10.1515/bmt-2016-0240.

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