English
 
Help Privacy Policy Disclaimer
  Advanced SearchBrowse

Item

ITEM ACTIONSEXPORT
  Linking electric field simulations and physiological measurements to reveal how TMS stimulates the human motor hand area

Thielscher, A., Antunes, A., Bungert, A., Espenhahn, S., Hamada, M., Sørensen, P., et al. (2017). Linking electric field simulations and physiological measurements to reveal how TMS stimulates the human motor hand area. In 47th Annual Meeting of the Society for Neuroscience (Neuroscience 2017).

Item is

Basic

show hide
Genre: Meeting Abstract

Files

show Files

Locators

show
hide
Locator:
Link (Any fulltext)
Description:
-

Creators

show
hide
 Creators:
Thielscher, A, Author              
Antunes, A1, 2, Author              
Bungert, A1, 2, Author              
Espenhahn, S, Author
Hamada, M, Author
Sørensen, PJ, Author
Rothwell, JC, Author
Siebner, HR, Author
Affiliations:
1Department High-Field Magnetic Resonance, Max Planck Institute for Biological Cybernetics, Max Planck Society, ou_1497796              
2Max Planck Institute for Biological Cybernetics, Max Planck Society, ou_1497794              

Content

show
hide
Free keywords: -
 Abstract: Knowledge of the type and position of the neural population stimulated by transcranial magnetic stimulation (TMS) is pivotal for a better understanding of the underlying physiological mechanisms and for advancing a systematic targeting and dosage approach. We will provide evidence that realistic field modeling informed by individual structural MRI, combined with measurements of the elicited motor evoked potentials (MEPs) can help to pinpoint the stimulated brain region and reveal the stimulation depth. We will further show that field modeling can contribute to the understanding of the neural origin of inter-individual differences in MEP latencies. In 9 healthy participants, we systematically varied the orientation of a standard figure-8 coil and compared the MEP threshold changes for monophasic TMS with the electric field changes in the motor cortex that were calculated using the Finite-Element Method (FEM). In addition, in another 9 participants, we used three figure-8 coils having different field decays to correlate the differences in the electrophysiological thresholds for current direction posterior-to-anterior (PA) with the differences in the calculated field distributions. These two experiments consistently showed that TMS stimulates the region of the crown and posterior lip of the precentral gyrus and that the maximal electric field strength in this region is significantly related to the MEP threshold. Finally, in 13 participants, we tested the correlation between the field in the motor cortex and the MEP onset delays for anterior-to-posterior (AP) current orientation. We demonstrated that the part of the motor cortex found in the two prior experiments also exhibited a significant negative correlation between the onset delays and the field strength. The results of our experiments validate the FEM-based field calculations by demonstrating a significant correlation between the electric field estimates and the physiological response to TMS. They further help to resolve uncertainties on the stimulation depth of TMS. They suggest that TMS at the optimal current orientation might mainly stimulate subarea BA 4a of the motor cortex at the transition from the posterior wall to the crown of the precentral gyrus. In addition, in those subjects in which lower field strengths are sufficient to induce a motor response for current orientation AP, later I-waves are recruited. This suggests that local inter-individual differences in cortical organization in the upper part of M1 might underlie the observed latency differences.

Details

show
hide
Language(s):
 Dates: 2017-11
 Publication Status: Published in print
 Pages: -
 Publishing info: -
 Table of Contents: -
 Rev. Type: -
 Identifiers: BibTex Citekey: ThielscherABEHSRS2017
 Degree: -

Event

show
hide
Title: 47th Annual Meeting of the Society for Neuroscience (Neuroscience 2017)
Place of Event: Washington, DC, USA
Start-/End Date: 2017-11-11 - 2017-11-15

Legal Case

show

Project information

show

Source 1

show
hide
Title: 47th Annual Meeting of the Society for Neuroscience (Neuroscience 2017)
Source Genre: Proceedings
 Creator(s):
Affiliations:
Publ. Info: -
Pages: - Volume / Issue: - Sequence Number: 739.06 Start / End Page: - Identifier: -