An electrode cuff (B) including a dielectric sleeve (10) and an annular cathode electrode (20) is disposed around a nerve trunk (A). An anode electrode (22) is disposed in body fluids in electrical communication with the nerve trunk. The cathode electrode is disposed off center within the dielectric sleeve. The flow of electric current from the anode to the cathode has a much greater amplitude along the nerve in the direction extending along the nerve trunk toward the cathode from the end of the dielectric sleeve toward which the cathode electrode is closest. A signal generator (C) applies a pulse train across the anode and cathode electrodes. The pulse train includes a plurality of alternating first amplitude pulse portions (40) and opposite polarity pulse portions (42). Each first polarity pulse includes a sharp leading edge (50) which rises abruptly to a preset amplitude (52). A trailing edge (56) of each first pulse portion decays smoothly into a leading edge (60) of each opposite polarity pulse portion without a discontinuity therebetween. The opposite polarity pulse portion has an amplitude (62) which is smaller than the triggering amplitude and a duration which is longer than the first polarity pulse portion duration. The amplitude and duration of the first and opposite polarity pulse portions are selected such that the net charge transfer in each direction is substantially the same.