An apparatus for implantation in the body to locally stimulate a mass of electrically excitable tissue without stimulating nearby tissue structures, and the method of so stimulating the tissue is described. The apparatus includes a plurality of electrodes, each of the electrodes including a pair of conductors for carrying signals of positive and negative polarity, each of said conductors having a plurality of electrically conductive coupling points for coupling to the mass of tissue. Apparatus is also described for providing timed sequenced electrical impulses to the plurality of electrodes so that only one of the electrodes has a voltage applied between its input terminals at any given time. An insulating backing placed between the electrodes and tissue structures surrounding the implanted stimulator for eliminating undesirable secondary tissue stimulation is also described. The method of applying controlled time-spaced electrical impulses to a mass of electrically excitable tissue structure for causing stimulation of that tissue structure is also described.