This work was supported by fellowship SFRH/BD/63773/2009 from the Foundation for Science and Technology, Portugal; was cofinanced by Quadro de Referência Estratégica Nacional (S.B.), strategic project UID/NEU/04539/2013 (A.P.S.), and the European Research Council (ERC) under the 7th Framework Programme for the European Community (FP7/2007-2013)/ERC Grant agreement No. 200808); “Investissements d’avenir” ANR-10-IAIHU-06; Agence Nationale de la Recherche (ANR-13-BSV4-0015-01), Fondation Recherche Médicale (Equipe FRM DEQ20150331684), and a grant from the Institut du Cerveau et de la Moelle épinière (Paris) (A.B.). A.B. is supported by a 2014 NARSAD Independent Investigator Grant from the Brain and Behavior Research Foundation.