On the magnetic field and the electrical potential generated by bioelectric sources in an anisotropic volume conductor

The electrical conductivity in biological tissue is often dependent on the direction of the fibres. In the paper the influence of this anisotropic nature on the electrical potential and magnetic field generated by a current dipole is studied analytically. Three different methods are discussed. The volume conductor is described by piecewise homogeneous compartments and the interfaces between compartments are either parallel or perpendicular to one of the principal axes. To illustrate the methods, the influence of the anisotropic nature is computed for a two-layered medium. It turns out that the influence on both the potential and the magnetic field cannot be ignored. However, for some commonly used models of the head and torso, a certain component of the magnetic field is not influenced by the anisotropy.

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