Transcranial magnetic stimulation is an attractive research and possibly therapeutic tool for non-invasive stimulation of brain tissue. However, relatively little is known about the direction, magnitude and distribution of induced fields and current flow in tissue, and optimal setup characteristics remain largely undetermined. Further, the profound influence of brain size and shape as well as of brain tissue irregularity on actual stimulation patterns is unclear. We model the conductive phenomena induced in brain tissue by TMS by solving the quasistatic problem over a realistic head model of 1 mm resolution derived from anatomical MRI scans using a finite difference successive overrelaxation procedure. The magnetic field is calculated from digitized coil geometry and realistic stimulator parameters. Stimulation with a symmetrical primary electric field results in electric field and current density distributions which are highly asymmetrical both in magnitude and in direction (i.e. distributed, non-contiguous stimulation peaks, deviation of stimulated area from coil "hot spot", sudden jumps in stimulation intensity and non-zero current flow across tissue interfaces). Knowledge of coil and stimulator specifications alone is hence not sufficient to control stimulation conditions, and a stereotaxic setup coupled with an individually adjusted field solver appears essential in performing reliable TMS studies. Our results bear direct relevance to any application of TMS, both investigative and therapeutic. © 2008.

Toschi, N., Welt, T., Guerrisi, M.g., Keck, M. (2008). A reconstruction of the conductive phenomena elicited by transcranial magnetic stimulation in heterogeneous brain tissue. PHYSICA MEDICA, 24(2), 80-86 [10.1016/j.ejmp.2008.01.005].

A reconstruction of the conductive phenomena elicited by transcranial magnetic stimulation in heterogeneous brain tissue

TOSCHI, NICOLA;GUERRISI, MARIA GIOVANNA;
2008-01-01

Abstract

Transcranial magnetic stimulation is an attractive research and possibly therapeutic tool for non-invasive stimulation of brain tissue. However, relatively little is known about the direction, magnitude and distribution of induced fields and current flow in tissue, and optimal setup characteristics remain largely undetermined. Further, the profound influence of brain size and shape as well as of brain tissue irregularity on actual stimulation patterns is unclear. We model the conductive phenomena induced in brain tissue by TMS by solving the quasistatic problem over a realistic head model of 1 mm resolution derived from anatomical MRI scans using a finite difference successive overrelaxation procedure. The magnetic field is calculated from digitized coil geometry and realistic stimulator parameters. Stimulation with a symmetrical primary electric field results in electric field and current density distributions which are highly asymmetrical both in magnitude and in direction (i.e. distributed, non-contiguous stimulation peaks, deviation of stimulated area from coil "hot spot", sudden jumps in stimulation intensity and non-zero current flow across tissue interfaces). Knowledge of coil and stimulator specifications alone is hence not sufficient to control stimulation conditions, and a stereotaxic setup coupled with an individually adjusted field solver appears essential in performing reliable TMS studies. Our results bear direct relevance to any application of TMS, both investigative and therapeutic. © 2008.
2008
Pubblicato
Rilevanza internazionale
Articolo
Sì, ma tipo non specificato
Settore FIS/07 - FISICA APPLICATA (A BENI CULTURALI, AMBIENTALI, BIOLOGIA E MEDICINA)
Settore MED/26 - NEUROLOGIA
Settore MED/25 - PSICHIATRIA
English
Con Impact Factor ISI
article; brain size; brain tissue; conductance; electric field; image reconstruction; magnetic field; mathematical computing; nuclear magnetic resonance scanner; transcranial magnetic stimulation, Biophysics; Brain; Electrophysiology; Humans; Magnetics; Models, Anatomic; Models, Neurological; Transcranial Magnetic Stimulation
Toschi, N., Welt, T., Guerrisi, M.g., Keck, M. (2008). A reconstruction of the conductive phenomena elicited by transcranial magnetic stimulation in heterogeneous brain tissue. PHYSICA MEDICA, 24(2), 80-86 [10.1016/j.ejmp.2008.01.005].
Toschi, N; Welt, T; Guerrisi, Mg; Keck, M
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2108/29079
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