Insl5 has been found to be orexigenic, i. The edge of the shank away from the tip of the fluke is curved and the free end of the shank is offset from a plane tangent to the back edge of the fluke and to the edge of the shank. The size of the aperture through which light energy is applied to the medium is also controlled so as to provide a desired amplification coefficient as a result of retroreflection. The proximity communication may be used to initially limit the number of devices that respond to a discovery request and then subsequently used to select the intended implantable medical device as well as automatically select the appropriate therapy application corresponding to the selected IMD.