1. INSERM-CEA Cognitive Neuroimaging Unit, Service Hospitalier Frédéric Joliot, Commissariat à l'Energie Atomique, 91401 Orsay Cedex, France.
2. Collège de France, 11, place Marcelin Berthelot, 75231 Paris Cedex 05, France.
3. Unité Mixte de Recherche 7023 “Formal Structure of Language,” CNRS and Paris VIII University, Paris, France.
4. Psychology Department, Harvard University, Cambridge, MA 02139, USA.