A single electrode, asymmetric electrode cuff (B) is disposed around a nerve trunk (A). A signal generator (C) is connected between a cathode (20) disposed asymmetrically in the electrode cuff and an anode (22) disposed in an electrically conductive relationship within the body tissue. The signal generator applies a stimulus signal (FIG. 3) which generates unidirectionally propagating action potentials on the nerve trunk. The electrode cuff includes a dielectric sleeve (10) in which the cathode is positioned a first distance (L1) from an escape end (14) and a second distance (L2) from an arrest end (16). The first distance is at least 1.7, and preferably about 7, times the second distance. This asymmetry causes a primary or forward stimulus signal current (30) to be correspondingly greater than a secondary or reverse current (32).