Cargando…
Local Differences in Cortical Excitability – A Systematic Mapping Study of the TMS-Evoked N100 Component
Transcranial magnetic stimulation (TMS) with simultaneous electroencephalography applied to the primary motor cortex provides two parameters for cortical excitability: motor evoked potentials (MEPs) and TMS-evoked potentials (TEPs). This study aimed to evaluate the effects of systematic coil shifts...
Autores principales: | , , , |
---|---|
Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Frontiers Media S.A.
2021
|
Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7959732/ https://www.ncbi.nlm.nih.gov/pubmed/33732105 http://dx.doi.org/10.3389/fnins.2021.623692 |
_version_ | 1783665013752332288 |
---|---|
author | Roos, Daniela Biermann, Lea Jarczok, Tomasz A. Bender, Stephan |
author_facet | Roos, Daniela Biermann, Lea Jarczok, Tomasz A. Bender, Stephan |
author_sort | Roos, Daniela |
collection | PubMed |
description | Transcranial magnetic stimulation (TMS) with simultaneous electroencephalography applied to the primary motor cortex provides two parameters for cortical excitability: motor evoked potentials (MEPs) and TMS-evoked potentials (TEPs). This study aimed to evaluate the effects of systematic coil shifts on both the TEP N100 component and MEPs in addition to the relationship between both parameters. In 12 healthy adults, the center of a standardized grid was fixed above the hot spot of the target muscle of the left primary motor cortex. Twelve additional positions were arranged in a quadratic grid with positions between 5 and 10 mm from the hot spot. At each of the 13 positions, TMS single pulses were applied. The topographical maximum of the resulting N100 was located ipsilateral and slightly posterior to the stimulation site. A source analysis revealed an equivalent dipole localized more deeply than standard motor cortex coordinates that could not be explained by a single seeded primary motor cortex dipole. The N100 topography might not only reflect primary motor cortex activation, but also sum activation of the surrounding cortex. N100 amplitude and latency decreased significantly during stimulation anterior-medial to the hot spot although MEP amplitudes were smaller at all other stimulation sites. Therefore, N100 amplitudes might be suitable for detecting differences in local cortical excitability. The N100 topography, with its maximum located posterior to the stimulation site, possibly depends on both anatomical characteristics of the stimulated cortex and differences in local excitability of surrounding cortical areas. The less excitable anterior cortex might contribute to a more posterior maximum. There was no correlation between N100 and MEP amplitudes, but a single-trial analysis revealed a trend toward larger N100 amplitudes in trials with larger MEPs. Thus, functionally efficient cortical excitation might increase the probability of higher N100 amplitudes, but TEPs are also generated in the absence of MEPs. |
format | Online Article Text |
id | pubmed-7959732 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2021 |
publisher | Frontiers Media S.A. |
record_format | MEDLINE/PubMed |
spelling | pubmed-79597322021-03-16 Local Differences in Cortical Excitability – A Systematic Mapping Study of the TMS-Evoked N100 Component Roos, Daniela Biermann, Lea Jarczok, Tomasz A. Bender, Stephan Front Neurosci Neuroscience Transcranial magnetic stimulation (TMS) with simultaneous electroencephalography applied to the primary motor cortex provides two parameters for cortical excitability: motor evoked potentials (MEPs) and TMS-evoked potentials (TEPs). This study aimed to evaluate the effects of systematic coil shifts on both the TEP N100 component and MEPs in addition to the relationship between both parameters. In 12 healthy adults, the center of a standardized grid was fixed above the hot spot of the target muscle of the left primary motor cortex. Twelve additional positions were arranged in a quadratic grid with positions between 5 and 10 mm from the hot spot. At each of the 13 positions, TMS single pulses were applied. The topographical maximum of the resulting N100 was located ipsilateral and slightly posterior to the stimulation site. A source analysis revealed an equivalent dipole localized more deeply than standard motor cortex coordinates that could not be explained by a single seeded primary motor cortex dipole. The N100 topography might not only reflect primary motor cortex activation, but also sum activation of the surrounding cortex. N100 amplitude and latency decreased significantly during stimulation anterior-medial to the hot spot although MEP amplitudes were smaller at all other stimulation sites. Therefore, N100 amplitudes might be suitable for detecting differences in local cortical excitability. The N100 topography, with its maximum located posterior to the stimulation site, possibly depends on both anatomical characteristics of the stimulated cortex and differences in local excitability of surrounding cortical areas. The less excitable anterior cortex might contribute to a more posterior maximum. There was no correlation between N100 and MEP amplitudes, but a single-trial analysis revealed a trend toward larger N100 amplitudes in trials with larger MEPs. Thus, functionally efficient cortical excitation might increase the probability of higher N100 amplitudes, but TEPs are also generated in the absence of MEPs. Frontiers Media S.A. 2021-02-25 /pmc/articles/PMC7959732/ /pubmed/33732105 http://dx.doi.org/10.3389/fnins.2021.623692 Text en Copyright © 2021 Roos, Biermann, Jarczok and Bender. https://creativecommons.org/licenses/by/4.0/This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. |
spellingShingle | Neuroscience Roos, Daniela Biermann, Lea Jarczok, Tomasz A. Bender, Stephan Local Differences in Cortical Excitability – A Systematic Mapping Study of the TMS-Evoked N100 Component |
title | Local Differences in Cortical Excitability – A Systematic Mapping Study of the TMS-Evoked N100 Component |
title_full | Local Differences in Cortical Excitability – A Systematic Mapping Study of the TMS-Evoked N100 Component |
title_fullStr | Local Differences in Cortical Excitability – A Systematic Mapping Study of the TMS-Evoked N100 Component |
title_full_unstemmed | Local Differences in Cortical Excitability – A Systematic Mapping Study of the TMS-Evoked N100 Component |
title_short | Local Differences in Cortical Excitability – A Systematic Mapping Study of the TMS-Evoked N100 Component |
title_sort | local differences in cortical excitability – a systematic mapping study of the tms-evoked n100 component |
topic | Neuroscience |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7959732/ https://www.ncbi.nlm.nih.gov/pubmed/33732105 http://dx.doi.org/10.3389/fnins.2021.623692 |
work_keys_str_mv | AT roosdaniela localdifferencesincorticalexcitabilityasystematicmappingstudyofthetmsevokedn100component AT biermannlea localdifferencesincorticalexcitabilityasystematicmappingstudyofthetmsevokedn100component AT jarczoktomasza localdifferencesincorticalexcitabilityasystematicmappingstudyofthetmsevokedn100component AT benderstephan localdifferencesincorticalexcitabilityasystematicmappingstudyofthetmsevokedn100component |