Rotational field TMS: Comparison with conventional TMS based on motor evoked potentials and thresholds in the hand and leg motor cortices.
MEP
Motor cortex
Motor threshold
Rotational field
TMS
Unidirectional
Journal
Brain stimulation
ISSN: 1876-4754
Titre abrégé: Brain Stimul
Pays: United States
ID NLM: 101465726
Informations de publication
Date de publication:
Historique:
received:
04
12
2019
revised:
20
02
2020
accepted:
16
03
2020
pubmed:
15
4
2020
medline:
24
11
2020
entrez:
15
4
2020
Statut:
ppublish
Résumé
Transcranial magnetic stimulation (TMS) is a rapidly expanding technology utilized in research and neuropsychiatric treatments. Yet, conventional TMS configurations affect primarily neurons that are aligned parallel to the induced electric field by a fixed coil, making the activation orientation-specific. A novel method termed rotational field TMS (rfTMS), where two orthogonal coils are operated with a 90° phase shift, produces rotation of the electric field vector over almost a complete cycle, and may stimulate larger portion of the neuronal population within a given brain area. To compare the physiological effects of rfTMS and conventional unidirectional TMS (udTMS) in the motor cortex. Hand and leg resting motor thresholds (rMT), and motor evoked potential (MEP) amplitudes and latencies (at 120% of rMT), were measured using a dual-coil array based on the H7-coil, in 8 healthy volunteers following stimulation at different orientations of either udTMS or rfTMS. For both target areas rfTMS produced significantly lower rMTs and much higher MEPs than those induced by udTMS, for comparable induced electric field amplitude. Both hand and leg rMTs were orientation-dependent. rfTMS induces stronger physiologic effects in targeted brain regions at significantly lower intensities. Importantly, given the activation of a much larger population of neurons within a certain brain area, repeated application of rfTMS may induce different neuroplastic effects in neural networks, opening novel research and clinical opportunities.
Sections du résumé
BACKGROUND
Transcranial magnetic stimulation (TMS) is a rapidly expanding technology utilized in research and neuropsychiatric treatments. Yet, conventional TMS configurations affect primarily neurons that are aligned parallel to the induced electric field by a fixed coil, making the activation orientation-specific. A novel method termed rotational field TMS (rfTMS), where two orthogonal coils are operated with a 90° phase shift, produces rotation of the electric field vector over almost a complete cycle, and may stimulate larger portion of the neuronal population within a given brain area.
OBJECTIVE
To compare the physiological effects of rfTMS and conventional unidirectional TMS (udTMS) in the motor cortex.
METHODS
Hand and leg resting motor thresholds (rMT), and motor evoked potential (MEP) amplitudes and latencies (at 120% of rMT), were measured using a dual-coil array based on the H7-coil, in 8 healthy volunteers following stimulation at different orientations of either udTMS or rfTMS.
RESULTS
For both target areas rfTMS produced significantly lower rMTs and much higher MEPs than those induced by udTMS, for comparable induced electric field amplitude. Both hand and leg rMTs were orientation-dependent.
CONCLUSIONS
rfTMS induces stronger physiologic effects in targeted brain regions at significantly lower intensities. Importantly, given the activation of a much larger population of neurons within a certain brain area, repeated application of rfTMS may induce different neuroplastic effects in neural networks, opening novel research and clinical opportunities.
Identifiants
pubmed: 32289723
pii: S1935-861X(20)30063-2
doi: 10.1016/j.brs.2020.03.010
pii:
doi:
Types de publication
Comparative Study
Journal Article
Research Support, Non-U.S. Gov't
Langues
eng
Sous-ensembles de citation
IM
Pagination
900-907Informations de copyright
Copyright © 2020 The Author(s). Published by Elsevier Inc. All rights reserved.
Déclaration de conflit d'intérêts
Declaration of competing interest AZ and YR are inventors of deep TMS technology and have financial interest in Brainsway Ltd., a company that develops and commercialize deep TMS devices. GSP, MA, YH and AT are Brainsway employees. All other authors declare no competing interest.