An apparatus and method using an array of VCSELs operable to emit light at one or more wavelengths, pulse-repetition rates, pulse durations, pulse powers, pulse energies, and / or light-distribution spatial and / or temporal patterns, that are effective to stimulate or photostimulate human or other animal tissue, and in particular, nerve tissue. In some embodiments, the invention provides an implantable device that includes an array having a plurality of VCSELs in a spatial pattern suitable to stimulate or photostimulate a plurality of different areas of tissue (e.g., a plurality of different nerves). In some embodiments, the device is instead partially implantable. In some embodiments, the device is instead external to the body of the animal.