ANALYSIS OF THE STIMULATION OF A NERVE FIBER SURROUNDED BY AN INHOMOGENEOUS~ ANISOTROPIC, AND DISPERSIVE TISSUE

Abstract

A method for evaluating the threshold for electric and magnetic stimulation of nerves surrounded by an inhomogeneous, anisotropic, and dispersive tissue has been developed. The scalar potential distribution induced by a given electric or magnetic source is evaluated by using the Finite Difference Technique. Calculations are perforrned with a FORTRAN code, and for non dispersive tissues a spread-sheet is also used. Nerve fiber excitation is described by using the FrankenhaeuserHuxley model in which the stimulating current density is obtained by extending the method proposed by Rattay. The analysis results predict that, with reference to the homogeneous case usually considered in literature, the larger differences in the current threshold are due to the tissue inhomogeneity, while the consideration of the dispersive properties of the tissues has less effect. [Vol. 7, No. 2, pp. 179-190 (1992), Special Issue on Bioelectromagnetic Computations]