Simulation study of the magnetic field produced by a nerve fiber

Computer simulations were conducted to investigate the relationship between the magnetic field induced by the action of a nerve fiber and the distribution of its source current. The normal component of the magnetic field on a sensing plane produced by an active nerve fiber was calculated. A contour map of the magnetic field showed four peaks. It was found that the interpeak distance orthogonal to the nerve fiber was affected by the distance from the sensing plane to the fiber, and the interpeak distance parallel to the fiber was affected by both the diameter of the fiber and the distance from the sensing plane to the fiber. A procedure to estimate the location and active part of the nerve fiber from the interpeak distances of the contour of magnetic field is proposed.