Model of electrical conductivity of skeletal muscle based on tissue structure

Gielen, F.L.H.; Cruts, H.E.P.; Alberts, Bruce; Boon, Kathy; Wallinga, W.; Boom, H.B.K.

doi:10.1007/bf02441603

Cited by 59 publications

(18 citation statements)

References 9 publications

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“…The muscle fiber is represented as a circular inclusion 10 μm in radius, a s , surrounded by a thin shell 10 nm in thickness, T s . Although the value of a s (a s = 10 μm) is somewhat smaller than those used in previous theoretical simulations [28,31], it is still realistic. The T s value (T s = 10 nm) was chosen for a practical reason to simplify the calculations, and is larger than the thickness of the hydrophobic region in cell membranes ranging from 4 to 5 nm [2][3][4].…”

Section: Cell Modelsmentioning

confidence: 82%

Effects of T-tubules on dielectric spectra of skeletal muscle simulated by boundary element method with two-dimensional models

Sekine

Hibino

Kimura

et al. 2007

Bioelectrochemistry

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In order to investigate the origin of large intensity the α-relaxation in skeletal muscles observed in dielectric measurements with extracellular electrode methods, effects of the interfacial polarization in the T-tubules on dielectric spectra were evaluated with the boundary-element method using two-dimensional models in which the structure of the T-tubules were represented explicitly. Each model consisted of a circular inclusion surrounded by a thin shell corresponding to the sarcolemma.The T-tubules were represented by simplified two types of invagination of the shell: straight invagination along the radial directions, and branched one. Each of the models was subjected to two kinds of calculations relevant to experiments with the extracellular and the intracellular electrode methods. Electrical interactions between the cells were omitted in the calculations. The both calculations showed that the dielectric spectra of the models contained two relaxation terms. The low-frequency relaxation term assigned to the α-relaxation depended on the structure of the T-tubules.Values of the relaxation frequency of the α-relaxation obtained from the two types of calculations agreed with each other. At the low-frequency limit, the permittivity obtained from the extracellular-electrode-type calculations varied in proportion to the capacitance obtained from the intracellular-electrode-type ones. These results were consistent with conventional lumped and distributed circuit models for the T-tubules. This confirms that the interfacial polarization in the T-tubules in a single muscle cell is not sufficient to explain the experimental results in which the intensity of the α-relaxation in the extracellular-electrode-type experiments exceeded the intensity expected from the results of the intracellular-electrode-type experiments. The high-frequency relaxation term that was assigned to the β-relaxation was also affected by the T-tubule structure in the calculations relevant to the extracellular-electrode-type experiments.

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Section: Cell Modelsmentioning

confidence: 82%

Effects of T-tubules on dielectric spectra of skeletal muscle simulated by boundary element method with two-dimensional models

Sekine

Hibino

Kimura

et al. 2007

Bioelectrochemistry

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“…In a nerve bundle, D/ depends on the anisotropy of the bundle [36]. The presence of nonconducting, non-homogeneities in the volume conductor surrounding the nerve bundles reduces excitation thresholds [18]. For lower values of conductance of perineurium, the transverse field becomes significantly weaker [51].…”

Section: Future Directionsmentioning

confidence: 98%

Transmembrane potential generated by a magnetically induced transverse electric field in a cylindrical axonal model

Cotic

Fehlings

et al. 2010

Med Biol Eng Comput

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During the electrical stimulation of a uniform, long, and straight nerve axon, the electric field oriented parallel to the axon has been widely accepted as the major field component that activates the axon. Recent experimental evidence has shown that the electric field oriented transverse to the axon is also sufficient to activate the axon, by inducing a transmembrane potential within the axon. The transverse field can be generated by a time-varying magnetic field via electromagnetic induction. The aim of this study was to investigate the factors that influence the transmembrane potential induced by a transverse field during magnetic stimulation. Using an unmyelinated axon model, we have provided an analytic expression for the transmembrane potential under spatially uniform, time-varying magnetic stimulation. Polarization of the axon was dependent on the properties of the magnetic field (i.e., orientation to the axon, magnitude, and frequency). Polarization of the axon was also dependent on its own geometrical (i.e., radius of the axon and thickness of the membrane) and electrical properties (i.e., conductivities and dielectric permittivities). Therefore, this article provides evidence that aside from optimal coil design, tissue properties may also play an important role in determining the efficacy of axonal activation under magnetic stimulation. The mathematical basis of this conclusion was discussed. The analytic solution can potentially be used to modify the activation function in current cable equations describing magnetic stimulation.

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“…Assumption 3. Colonic tissue is a thin, linear and isotropic volume conductor medium composed of homogeneous blocks with effective macroscopic conductivity (s eff ) modelling the multilayer structure of the intestinal wall [21,22]. The effective macroscopic conductivity seff is limited by the average extracellular and intracellular conductivity, both associated with linearized passive electrical properties [18,23].…”

Section: Parametric Modelling Of Colonic Electrical Stimulation In Vivomentioning

confidence: 99%

Three-dimensional static parametric modelling of phasic colonic contractions for the purpose of microprocessor-controlled functional stimulation

Rashev

Mintchev

Bowes³

2001

Journal of Medical Engineering & Technology

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The study aimed at creating an integrated electromechanical model of invoked phasic contractions in canine colon during direct high frequency voltage stimulation. The model utilized data obtained from two large anaesthetized dogs that underwent laparotomy and serosal implantation of two circumferential electrode pairs into a distal segment of the left colon. The strength distribution of the stimulating electric field was analysed over a cylindrical mesh-surface grid modelling the interrogated colonic segment. Recordings of the stimulating current were utilized to model smooth muscle depolarization using linearized macroscopic tissue conductivity. The invoked contractile stress was related to the stimulating electric field strength using an exponential sigmoid function. Artificially produced occlusion of the lumen was derived for a pair of 5mm electrodes positioned on a cylindrical mesh-surface of 2 cm diameter and 15 cm length. The model simulated contractions invoked by stimuli of different amplitude (up to 12 V) with 98.6% accuracy of approximation. Macroscopic tissue conductivity was modelled as a combination of two first-order exponential terms involving a 3ms time constant. Real-time simulation of the current drawn by the smooth muscle during 10 V/50Hz bipolar voltage stimulation was performed. The integrated electromechanical model facilitates the quantification of microprocessor-controlled phasic colonic contractions.

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Model of electrical conductivity of skeletal muscle based on tissue structure

Cited by 59 publications

References 9 publications

Effects of T-tubules on dielectric spectra of skeletal muscle simulated by boundary element method with two-dimensional models

Effects of T-tubules on dielectric spectra of skeletal muscle simulated by boundary element method with two-dimensional models

Transmembrane potential generated by a magnetically induced transverse electric field in a cylindrical axonal model

Three-dimensional static parametric modelling of phasic colonic contractions for the purpose of microprocessor-controlled functional stimulation

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