Effects of Strong Static Magnetic Fields on Nerve Excitation

Recent advances in superconducting magnets for medical devices and for magnetic levitation have given rise to the importance of understanding the biological effects of magnetic fields. The purpose of this study was to investigate the effects of strong static magnetic fields on the action potentials of the rat sciatic nerve. A pair of needle electrodes was inserted beneath the skin of the heel for applying electrical stimulations. Compound action potentials of the left sciatic nerve were measured from a pair of electrodes attached to the nerve bundle under static magnetic fields of up to 8 T. We identified the action potentials originating from the Aalpha and C fibers. The exposure to a static magnetic field did not affect the amplitude of the Aalpha action potentials. An increase in the static magnetic field increases the amplitudes of the peaks of the C fiber. These results indicated that exposure to strong static magnetic fields enhances the excitation of nerve fibers, and this effect depends on the type of fibers involved