A STUDY OF THE FEASIBILITY OF STIMULATING NEURONS BY ELECTROMAGNETIC WAVES.

This study was to determine the feasibility of using externally applied electromagnetic fields to selectively stimulate electrically any desired point deep in the brain of primates using external electrodes. The squirrel monkey was chosen as the animal specimen for all calculations. Values of the dielectric constants and conductivity of biological tissue and the consequent electromagnetic properties were applied to three potential methods described in detail, including a pulsing technique, a focusing lens system, and a method of creating standing waves in the brain. For all three methods, it was found to be impossible to electrically stimulate neurons within the brain using microwave frequencies. This is because relatively high frequencies are necessary to obtain accuracy, but attenuation of the electrical field increases exponentially with frequency, thereby limiting depth of penetration. One possible solution is to search for an attenuation window in brain substance, much as exists for sea water at visible light frequencies. Author