1. An implantable electrode, comprising: a) a first portion of an insulator layer; b) an electrically conductive interconnect layer supported by the first portion of the insulator layer, the interconnect layer comprising an interconnect peripheral edge providing an interconnect width or diameter extending between spaced apart first and second interconnect edges; c) an electrically conductive plug layer supported directly on an upper interconnect surface of the interconnect layer, the plug layer comprising a plug peripheral edge providing a plug width or diameter extending between spaced apart first and second plug edges; d) a second portion of the insulator layer supported on the first portion of the insulator layer and contacting the plug; e) an electrically conductive electrode layer supported directly on an upper plug surface of the plug layer, the electrode layer comprising an electrode peripheral edge providing an electrode width or diameter extending between spaced apart first and second electrode edges; and f) an anchor layer in an overlapping relationship with the electrode layer adjacent to at least one of the first and second electrode edges.