Mini-coil for magnetic stimulation in the behaving primate

Tischler, Hadass; Wolfus, Shuki; Friedman, Alexander; Perel, Eli; Pashut, Tamar; Lavidor, Michal; Korngreen, Alon; Yeshurun, Y.; Bar‐Gad, Izhar

doi:10.1016/j.jneumeth.2010.10.015

Cited by 32 publications

(24 citation statements)

References 33 publications

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“…Simulation models of 50 TMS coil configurations: (1) Animal mini-coil, 145 (2) Magstim 50 mm circular coil (P/N 9999), 146 (3) 50 mm circular coil with iron core, 70 (4) Magstim 70 mm circular coil (P/N 3192), 146 (5) Magstim 90 mm circular coil (P/N 3192), 146 (6) Magstim animal MST coil, (7) Magstim human MST coil (S/N MP39), (8) Brainsway H coil, 147 (9) Brainsway H1 coil, 76,80–83,147 (10) H1 coil with frontal iron core, 79 (11) H1 coil with lateral iron core, 79 (12) Brainsway H1L coil, 80 (13) Brainsway H2 coil, 76,80,81,147 (14) Brainsway HADD coil, 116 (15) Magstim cap coil, (16) crown coil, 3 (17) crown coil with back-splayed winding, (18) crown coil with back-spaced winding, (19) supraorbital halo coil, 98,99 (20) MRI z-gradient coil in parallel-current (Helmholz) mode, 100 (21) 3-layer double coil, 62 (22) double butterfly, 56,58,59 (23) circular slinky-7 coil, 52,53 (24) rectangular slinky-7 coil, 12,53,54 (25) Magstim 25 mm figure-8 (P/N 1165), 21,146 (26) Cadwell Corticoil, 148 (27) Cadwell B-shaped coil, 21 (28) 50 mm V-coil, 13 (29) MagVenture C-B65 butterfly coil, 149 (30) MagVenture MC-B70 butterfly coil, 26,27,149 (31) Magstim 70 mm figure-8 coil (P/N 9925, 3190), 146 (32) 70 mm figure-8 with shielding plate, 65 (33) 70 mm figure-8 with active shield (5 turns), 69 (34) Neuronetics iron-core figure-8 coil (CRS 2100), 28,68 (35) MagVenture D-B80 butterfly coil, 27,149 (36) MagVenture MST twin coil, (37) Magstim double cone coil (P/N 9902), 146 (38) eccentric double cone coil with center-dense windings, (39) eccentric double cone coil with center-sparse windings, (40) stretched C-core coil, 3,68 (41) 3-D differential coil, 60 (42) 3-D coil array #1, 114 (43) 3-D coil array #2, 114 (44) 3-D coil array #3, 114 (45) Cadwell cloverleaf coil, 48,49 (46) circular coil array, 110,150 (47) Magstim 70 mm figure-8 coil in reversed-current mode, 15...…”

Section: Figurementioning

confidence: 99%

Electric field depth–focality tradeoff in transcranial magnetic stimulation: Simulation comparison of 50 coil designs

2013

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Background Various transcranial magnetic stimulation (TMS) coil designs are available or have been proposed. However, key coil characteristics such as electric field focality and attenuation in depth have not been adequately compared. Knowledge of the coil focality and depth characteristics can help TMS researchers and clinicians with coil selection and interpretation of TMS studies. Objective To quantify the electric field focality and depth of penetration of various TMS coils. Methods The electric field distributions induced by 50 TMS coils were simulated in a spherical human head model using the finite element method. For each coil design, we quantified the electric field penetration by the half-value depth, d1/2, and focality by the tangential spread, S1/2, defined as the half-value volume (V1/2) divided by the half-value depth, S1/2 = V1/2/d1/2. Results The 50 TMS coils exhibit a wide range of electric field focality and depth, but all followed a depth–focality tradeoff: coils with larger half-value depth cannot be as focal as more superficial coils. The ranges of achievable d1/2 are similar between coils producing circular and figure-8 electric field patterns, ranging 1.0–3.5 cm and 0.9–3.4 cm, respectively. However, figure-8 field coils are more focal, having S1/2 as low as 5 cm2 compared to 34 cm2 for circular field coils. Conclusions For any coil design, the ability to directly stimulate deeper brain structures is obtained at the expense of inducing wider electrical field spread. Novel coil designs should be benchmarked against comparison coils with consistent metrics such as d1/2 and S1/2.

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Section: Figurementioning

confidence: 99%

Electric field depth–focality tradeoff in transcranial magnetic stimulation: Simulation comparison of 50 coil designs

2013

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“…Unfortunately, the large size of TMS coils prohibits implantation and until recently, the possibility of implanting smaller coils into the parenchyma was not considered viable because the fields induced by small coils were thought to be not strong enough to modulate neuronal activity. However, several recent studies have found that small coils [36], [37], including ones as small as 0.5 mm in diameter [36], could in fact activate neurons. Because such coils are small enough to be implanted, these findings raise the possibility that micromagnetic stimulation ( μ MS) could form the basis of one or more next-generation neural prosthetic devices.…”

Section: Introductionmentioning

confidence: 99%

Suppression of Subthalamic Nucleus Activity by Micromagnetic Stimulation

Lee

Fried

2015

IEEE Trans. Neural Syst. Rehabil. Eng.

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Magnetic stimulation delivered via 0.5-mm diameter coils was recently shown to activate retinal neurons; the small coil size raises the possibility that micromagnetic stimulation (μMS) could underlie a new generation of implanted neural prosthetics. Such an approach has several inherent advantages over conventional electric stimulation, including the potential for selective activation of neuronal targets as well as less susceptibility to inflamma-tory responses. The viability of μMS for some applications, e.g., deep brain stimulation (DBS), may require suppression (rather than creation) of neuronal activity, however, and therefore we explore here whether (μMS) could, in fact, suppress activity. While single pulses elicited weak and inconsistent spiking in neurons of the mouse subthalamic nucleus (in vitro), repetitive stimulation effectively suppressed activity in ~70% of targeted neurons. This is the same percentage suppressed by conventional electric stimulation; with both modalities, suppression occurred only after an initial increase in spiking. The latency to the onset of suppression was inversely correlated to the energy of the stimulus waveform: larger amplitudes and lower frequencies had the fastest onset of suppression. These findings continue to support the viability of μMS as a next-generation implantable neural prosthetic.

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“…To study the effect of stimulation parameters (magnitude and pulse width of coil current), many studies used frog sciatic nerve in in vitro experiments, [11], [15], [16]. Other studies focused on in vivo experiments, performing peripheral stimulation of rabbit sciatic nerve [7] and transcranial stimulation in behaving primates [17]. These experiments established stimulation thresholds in terms of stimulation voltage [11] or induced electric field magnitude [7].…”

Section: Introductionmentioning

confidence: 99%

A <inline-formula><tex-math>$\mu$</tex-math></inline-formula>m-Scale Computational Model of Magnetic Neural Stimulation in Multifascicular Peripheral Nerves

RamRakhyani

Kagan

Warren

et al. 2015

IEEE Trans. Biomed. Eng.

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There has been recurring interest in using magnetic neural stimulation for implantable localized stimulation. However, the large stimulation voltages and energies necessary to evoke neuronal activity have tempered this interest. To investigate the potential of magnetic stimulation as a viable methodology and to provide the ability to investigate novel coil designs that can result in lower stimulation threshold voltages and energies, there is a need for a model that accurately predicts the magnetic field-tissue interaction that results in neuronal stimulation. In this study, we provide a computational framework to accurately estimate the stimulation threshold and have validated the model with in vivo magnetic stimulation experiments. To make such predictions, we developed a micrometer-resolution anatomically driven computational model of rat sciatic nerve and quantified the effect of tissue heterogeneity (i.e., fascicular organization, axon distribution, and density) and axonal membrane capacitance on the resulting threshold. Using the multiresolution impedance method, we computed the spatial-temporal distribution of the induced electric field in the nerve and applied this field to a Frankenhaeuser-Huxley axon model in NEURON to simulate the nonlinear mechanisms of the membrane channels. The computational model developed predicts the stimulation thresholds for four magnetic coil designs with different geometrical parameters within the 95% confidence interval (experiments count = 4) of measured in vivo stimulation thresholds for the rat sciatic nerve.

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Mini-coil for magnetic stimulation in the behaving primate

Cited by 32 publications

References 33 publications

Electric field depth–focality tradeoff in transcranial magnetic stimulation: Simulation comparison of 50 coil designs

Electric field depth–focality tradeoff in transcranial magnetic stimulation: Simulation comparison of 50 coil designs

Suppression of Subthalamic Nucleus Activity by Micromagnetic Stimulation

A <inline-formula><tex-math>$\mu$</tex-math></inline-formula>m-Scale Computational Model of Magnetic Neural Stimulation in Multifascicular Peripheral Nerves

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