Magnetic nerve stimulation without interlinkage between nerve and magnetic flux

A new method of magnetic stimulation of nerves is proposed. Nerves are located on a core aperture outside the core which is implanted in the body. Nerves can be stimulated by the secondary currents which flow in the body fluids around the core when the magnetic flux in the core is changed. One of the advantages in this method is to be able to avoid the interlinkage between the core and nerves. The equivalent resistance of tissues around the core is calculated, and current density for nerve excitation is estimated. The validity of the new method is demonstrated by experiments using frog nerve-muscle preparations. The results show that the nerve can be excited by a change of magnetic flux which generates an EMF of 0.8-volts peak amplitude and 0.8-ms duration in a monitor wire. The current density in the vicinity of the core aperture for nerve excitation is 3.2 mA/cm².