A multi-scale computational model of the effects of TMS on motor cortex [version 1; referees: 2 approved with reservations]

  • The detailed biophysical mechanisms through which transcranial magnetic stimulation (TMS) activates cortical circuits are still not fully understood. Here we present a multi-scale computational model to describe and explain the activation of different cell types in motor cortex due to transcranial magnetic stimulation. Our model determines precise electric fields based on an individual head model derived from magnetic resonance imaging and calculates how these electric fields activate morphologically detailed models of different neuron types. We predict detailed neural activation patterns for different coil orientations consistent with experimental findings. Beyond this, our model allows us to predict activation thresholds for individual neurons and precise initiation sites of individual action potentials on the neurons’ complex morphologies. Specifically, our model predicts that cortical layer 3 pyramidal neurons are generally easier to stimulate than layer 5 pyramidal neurons, thereby explaining the lower stimulation thresholds observed for I-waves compared to D-waves. It also predicts differences in the regions of activated cortical layer 5 and layer 3 pyramidal cells depending on coil orientation. Finally, it predicts that under standard stimulation conditions, action potentials are mostly generated at the axon initial segment of corctial pyramidal cells, with a much less important activation site being the part of a layer 5 pyramidal cell axon where it crosses the boundary between grey matter and white matter. In conclusion, our computational model offers a detailed account of the mechanisms through which TMS activates different cortical cell types, paving the way for more targeted application of TMS based on individual brain morphology in clinical and basic research settings.
Author:Hyeon Seo, Natalie Schaworonkow, Sung Chan Jun, Jochen TrieschORCiD
Pubmed Id:https://pubmed.ncbi.nlm.nih.gov/28408973
Parent Title (English):F1000Research
Publisher:F1000 Research Ltd
Place of publication:London
Contributor(s):Axel Thielscher, Socrates Dokos
Document Type:Article
Year of Completion:2016
Date of first Publication:2016/08/10
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2018/08/16
Tag:D-wave; I-wave; brain stimulation; compartmental neuron model; computational model; motor cortex; multi-scale modeling; transcranial magnetic stimulation
Edition:version 1
Page Number:24
First Page:1
Last Page:24
Copyright: © 2017 Seo H et al. This is an open access article distributed under the terms of the Creative Commons Attribution Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Data associated with the article are available under the terms of the Creative Commons Zero "No rights reserved" data waiver (CC0 1.0 Public domain dedication).
Institutes:Physik / Physik
Wissenschaftliche Zentren und koordinierte Programme / Frankfurt Institute for Advanced Studies (FIAS)
Dewey Decimal Classification:6 Technik, Medizin, angewandte Wissenschaften / 61 Medizin und Gesundheit / 610 Medizin und Gesundheit
Licence (German):License LogoCreative Commons - Namensnennung 4.0