Apparatus, system, and method for activating muscle contractions along a GE tract portion. Implantable apparatus includes: elongated member configured for positioning lengthwise in GI tract across a target GI tract portion plurality of electrodes distributed longitudinally spaced in a series along the elongated member and array of controlled relays coupled to the electrodes, that facilitates selective transition of each electrode between positively connected, grounded, and disconnected states. Implantable apparatus is connectable to an external unit including a signal generator connectable to the electrodes via the controlled relays, and controller connected to memory with preset commands set for activating generator to generate signal sequences configured to charge positive electrode into positively connected state and negative electrode into grounded state, thereby producing an electrical field that activates local muscle contraction of the GI tract portion between the positive and negative electrodes, when in contact with the positive and negative electrodes.
