Magnetic Stimulation of the Brain and Spinal Cord by a Pair of Opposing Pulsed Magnetic Fields

A method of localized stimulation of the human brain and spinal cord is proposed. The basic idea is to concentrate induced eddy currents locally in the vicinity of a target by a pair of opposing pulsed magnetic fields. A figure-of-eight coil was designed, and magnetic stimulation of brain and spinal roots were carried out. The results show that the functional mapping of the human motor cortex related to the hand, arm and foot areas can be obtained. Experiments using rabbits were carried out to verify the usefulness of magnetic stimulation of the spinal cord in detail. Selective stimulation of each spinal segment from outside of the body was possible. It was also found that the amplitude of the EMG signals varies with the direction of the stimulating currents.