MTV Networks Chairman and CEO Judy McGrath is stepping down, parent company Viacom announced Thursday; she will not be replaced. McGrath started with the company in 1981, when she was working as a copywriter. She was named chairman and CEO of MTV Networks in 2004. “I leave with pride, joy, and gratitude for the ride of a lifetime,” she said in a statement. All MTV division heads are going to report directly to Viacom President and CEO Philippe Dauman.