Effect of Model Accuracy on the Result of Computed Current Densities in the Simulation of Transcranial Magnetic Stimulation

Golestanirad, Laleh; Mattes, Michael; Mosig, J. R.; Pollo, Claudio

doi:10.1109/tmag.2010.2082556

Cited by 26 publications

(20 citation statements)

References 9 publications

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“…Full-wave methods have been extensively used to address the interaction of electromagnetic waves and living tissues (Golestani-Rad et al, 2007; Golestanirad et al, 2010, 2012a,b). To investigate the performance of the proposed modified fractal electrodes, three-dimensional (3D) finite element models of fractal electrodes were developed inside a 3D homogenous conducting medium (Figure 4).…”

Section: Methodsmentioning

confidence: 99%

Analysis of fractal electrodes for efficient neural stimulation

Golestanirad¹,

Elahi²,

Molina³

et al. 2013

Front. Neuroeng.

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Planar electrodes are increasingly used in therapeutic neural stimulation techniques such as functional electrical stimulation, epidural spinal cord stimulation (ESCS), and cortical stimulation. Recently, optimized electrode geometries have been shown to increase the efficiency of neural stimulation by increasing the variation of current density on the electrode surface. In the present work, a new family of modified fractal electrode geometries is developed to enhance the efficiency of neural stimulation. It is shown that a promising approach in increasing the neural activation function is to increase the “edginess” of the electrode surface, a concept that is explained and quantified by fractal mathematics. Rigorous finite element simulations were performed to compute electric potential produced by proposed modified fractal geometries. The activation of 256 model axons positioned around the electrodes was then quantified, showing that modified fractal geometries required a 22% less input power while maintaining the same level of neural activation. Preliminary in vivo experiments investigating muscle evoked potentials due to median nerve stimulation showed encouraging results, supporting the feasibility of increasing neural stimulation efficiency using modified fractal geometries.

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Section: Methodsmentioning

confidence: 99%

Analysis of fractal electrodes for efficient neural stimulation

Golestanirad¹,

Elahi²,

Molina³

et al. 2013

Front. Neuroeng.

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“…To enhance stability and increase speed, magnetic stimulation has been modeled with a variety of equation systems derived from Maxwell’s equations. Alternative equation systems are, for instance, the T-Ω formulation to enforce stability by a more appropriate choice of potentials, and various ways to decouple the coil and the induced currents so that the back-action of the small induced current on the coil current (Goetz, Afinowi, et al, 2013; Golestanirad, Mattes, Mosig, & Pollo, 2010; Miranda, Hallett, & Basser, 2003; Opitz, et al, 2011; Sawicki, Starzynski, & Wincenciak, 2006; Thielscher, Opitz, & Windhoff, 2011; Wagner et al, 2008; Wagner et al, 2014; Yang et al, 2006). The so-called A - V formulation of the magnetic field first solves the magnetic vector potential ( A ), then in a second step, derives the electric scalar potential ( V ).…”

Section: Models Of the Induced Electric Field Distributionmentioning

confidence: 99%

The development and modelling of devices and paradigms for transcranial magnetic stimulation

Goetz

Deng

2017

International Review of Psychiatry

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Magnetic stimulation is a noninvasive neurostimulation technique that can evoke action potentials and modulate neural circuits through induced electric fields. Biophysical models of magnetic stimulation have become a major driver for technological developments and the understanding of the mechanisms of magnetic neurostimulation and neuromodulation. Major technological developments involve stimulation coils with different spatial characteristics and pulse sources to control the pulse waveform. While early technological developments were the result of manual design and invention processes, there is a trend in both stimulation coil and pulse source design to mathematically optimize parameters with the help of computational models. To date, macroscopically highly realistic spatial models of the brain as well as peripheral targets, and user-friendly software packages enable researchers and practitioners to simulate the treatment-specific and induced electric field distribution in the brains of individual subjects and patients. Neuron models further introduce the microscopic level of neural activation to understand the influence of activation dynamics in response to different pulse shapes. A number of models that were designed for online calibration to extract otherwise covert information and biomarkers from the neural system recently form a third branch of modeling.

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“…Full-wave methods have been extensively used to address the interaction of electromagnetic waves and living tissues (Golestani-Rad et al, 2007;Golestanirad et al, 2010Golestanirad et al, , 2012a. To investigate the performance of the proposed modified fractal electrodes, three-dimensional (3D) finite element models of fractal electrodes were developed inside a 3D homogenous conducting medium (Figure 4).…”

Section: Finite Element Modelingmentioning

confidence: 99%

Analysis of fractal electrodes for efficient neural stimulation

Golestanirad¹,

Pollo

Graham³

2013

2013 35th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC)

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Planar electrodes are increasingly used in therapeutic neural stimulation techniques such as functional electrical stimulation, epidural spinal cord stimulation (ESCS), and cortical stimulation. Recently, optimized electrode geometries have been shown to increase the efficiency of neural stimulation by increasing the variation of current density on the electrode surface. In the present work, a new family of modified fractal electrode geometries is developed to enhance the efficiency of neural stimulation. It is shown that a promising approach in increasing the neural activation function is to increase the "edginess" of the electrode surface, a concept that is explained and quantified by fractal mathematics. Rigorous finite element simulations were performed to compute electric potential produced by proposed modified fractal geometries. The activation of 256 model axons positioned around the electrodes was then quantified, showing that modified fractal geometries required a 22% less input power while maintaining the same level of neural activation. Preliminary in vivo experiments investigating muscle evoked potentials due to median nerve stimulation showed encouraging results, supporting the feasibility of increasing neural stimulation efficiency using modified fractal geometries.

show abstract

Effect of Model Accuracy on the Result of Computed Current Densities in the Simulation of Transcranial Magnetic Stimulation

Cited by 26 publications

References 9 publications

Analysis of fractal electrodes for efficient neural stimulation

Analysis of fractal electrodes for efficient neural stimulation

The development and modelling of devices and paradigms for transcranial magnetic stimulation

Analysis of fractal electrodes for efficient neural stimulation

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