US Patent 7917231 Directional stimulation of neural tissue

A multi-contact electrode for neural tissue stimulation is described. The electrode has an axis and includes a plurality of electrodes going along the axis. Each electrode ends with a contact, and at least one of the contacts has an internal edge, resulting in non-uniform electrical properties throughout the contact surface facing the tissue. Also described are methods of making an electrical contact with an internal edge, and methods and systems for characterizing internal edge.