An implantable neural stimulator includes one or more electrodes, at least one antenna, and one or more circuits connected to the at least one antenna. The one or more electrodes are configured to apply one or more electrical pulses to excitable tissue. The antenna is configured to receive one or more input signals containing polarity assignment information and electrical energy, the polarity assignment information designating polarities for the electrodes. The one or more circuits are configured to control an electrode interface such that the electrodes have the polarities designated by the polarity assignment information； create one or more electrical pulses using the electrical energy contained in the input signal； and supply the one or more electrical pulses to the one or more electrodes through the electrode interface so that the one or more electrical pulses are applied according to the polarities designated by the polarity assignment information.
