The low-frequency dielectric properties of octopus arm muscle measuredin vivo

Abstract

The conductance and capacitance of octopus arm are measured in vivo over the frequency range 5 Hz to 1 MHz. Measurement of these parameters for a number of electrode separations permits the determination of the variations in tissue conductivity and dielectric constant with frequency. In the range 1-100 kHz the conductivity is independent of the frequency f and the dielectric constant varies as f-1. These results, in conjunction with those reported previously for frog skeletal muscle, are consistent with the fractal model for the dielectric properties of animal tissue proposed by Dissado. Transformation of the results to complex impedance spectra indicates the presence of a dispersion above 100 kHz.

Transcranial magnetic stimulation and brain atrophy: a computer-based human brain model study

“…The tissue conductivities in the model were assigned the mean value from multiple compiled references; skin at 0.465 S/m, bone at 0.010 S/m, CSF at 1.654 S/m, gray matter at 0.276 S/ m, and white matter at 0.126 S/m (Crille et al 1922;Oswald 1937;Lepeschkin 1951;Freygang and Landau 1955;Ranck 1963;Radvan-Ziemnowicz et al 1964;Hasted 1973;Geddes 1987;De Mercato and Garcia Sanchez 1992;Gabriel and Gabriel 1996;Akhtari et al 2002;Kammer et al 2004); thus, each individual tetrahedron of the FEM was assigned the conductivity corresponding to its tissue type. Tissue permittivities were also assigned values reflective of trends in the literature (see Table 1) (Pethig and Kell 1987;Dissado 1990;Foster and Schwan 1996;Gabriel and Gabriel 1996;Hart et al 1996). The source was modeled as a figure-of-eight copper coil with two 3.5 cm radius windings made of a single turn of 7 mm radius copper wire.…”

Dielectric properties of a protein–water system in selected animal tissues

“…Moreover, the measurements of dielectric properties of tissues at low frequencies can be masked by the electrode polarization effects, despite the use of many techniques to overcome them. So, the available literature gives the results of the dielectric properties of human and animal tissues in incomplete adispersion region, i.e., starting from 10 Hz [10][11][12][13][14][15][16]. More information on the dielectric behaviour of biological materials in the a-dispersion has been collected for proteins [3,[17][18][19][20][21].…”

Finite element analysis of electrical impedance myography in the rat hind limb

“…Measurements were performed for needle electrodes distances of 4mm and 6mm using the system described above for the same range of frequencies. To minimize the effects of electrode resistance and reactance, we employed the technique described in [9]. …”