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Titolo:
Modeling the effects of electric fields on nerve fibers: Influence of tissue electrical properties
Autore:
Grill, WM;
Indirizzi:
Case Western Reserve Univ, Dept Biomed Engn, Appl Neural Control Lab, Cleveland, OH 44106 USA Case Western Reserve Univ Cleveland OH USA 44106 Cleveland, OH 44106 USA
Titolo Testata:
IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING
fascicolo: 8, volume: 46, anno: 1999,
pagine: 918 - 928
SICI:
0018-9294(199908)46:8<918:MTEOEF>2.0.ZU;2-#
Fonte:
ISI
Lingua:
ENG
Soggetto:
SPINAL-CORD STIMULATION; SOURCE-DENSITY ANALYSIS; MYELINATED NERVE; SKELETAL-MUSCLE; CONDUCTIVITY; EXCITATION; RECRUITMENT; SELECTIVITY; ACTIVATION; CURRENTS;
Keywords:
anisotropy; current-distance relationship; extra-cellular field; inhomogeneity; neural stimulation;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Engineering, Computing & Technology
Citazioni:
53
Recensione:
Indirizzi per estratti:
Indirizzo: Grill, WM Case Western Reserve Univ, Dept Biomed Engn, Appl Neural ControlLab, CB Bolton Bldg,Room 3480, Cleveland, OH 44106 USA Case Western Reserve Univ CB Bolton Bldg,Room 3480 Cleveland OH USA 44106
Citazione:
W.M. Grill, "Modeling the effects of electric fields on nerve fibers: Influence of tissue electrical properties", IEEE BIOMED, 46(8), 1999, pp. 918-928

Abstract

The effects of anisotropy and inhomogeneity of the electrical conductivityof extracellular tissue on excitation of nerve fibers by an extracellular point source electrode were determined by computer simulation. Analytical solutions to Poisson's equation were used to calculate potentials in anisotropic infinite homogeneous media and isotropic semi-infinite inhomogeneous media, and the net driving function was used to calculate excitation thresholds for nerve fibers. The slope and intercept of the current-distance curvein anisotropic media were power functions of the ratio and product of the orthogonal conductivities, respectively. Excitation thresholds in anisotropic media were also dependent on the orientation of the fibers, and in strongly anisotropic media (sigma(z)/sigma(xy) > 4) there were reversals in the recruitment order between different diameter fibers and between fibers at different distances from the electrode. In source-free regions of inhomogeneous media (two regions of differing conductivity separated by a plane boundary). the current-distance relationship of fibers parallel to the interfacewas dependent only on the average conductivity, whereas in regions containing the source the current-distance relationship was dependent on the individual, values of conductivity. Reversals in recruitment order between fibers at different distances from the electrode and between fibers of differingdiameter were found in inhomogeneous media. The results of this simulationstudy demonstrate that the electrical properties of the extracellular medium can have a strong influence on the pattern of neuronal excitation generated by extracellular electric fields, and indicate the importance of tissueelectrical properties in interpreting results of studies employing electrical stimulation applied in complex biological volume conductors.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 29/03/20 alle ore 22:50:24