[1] Univ Roma La Sapienza, Dipartimento Genet Biol Mol, I-00185 Rome, Italy
[2] Univ Roma La Sapienza, Ctr Res Neurobiol D Bovet, I-00185 Rome, Italy
[3] Univ Toulouse 3, Ctr Rech Cognit Anim, CNRS, UMR 5169, F-31062 Toulouse, France
[4] Univ Aix Marseille 1, Lab Neurobiol Cognit, CNRS, UMR 6155, F-13331 Marseille, France
[5] Univ Roma La Sapienza, Ist Pasteur, Fdn Cenci Bolognetti, Dipartimento Biol Cellulare & Sviluppo, I-00185 Rome, Italy
[6] CNR, Ist Neurosci, Ctr Europeo Ric Cervello, I-00143 Rome, Italy