[1] Harvard Univ, Sch Med, Dept Cell Biol, Boston, MA 02115 USA
[2] Massachusetts Gen Hosp, Stroke & Neurovasc Regulat Lab, Boston, MA 02129 USA
[3] Yale Univ, Sch Med, Program Neurogent, New Haven, CT 06520 USA
[4] Yale Univ, Sch Med, Dept Neurosurg, New Haven, CT 06520 USA
[5] Harvard Univ, Sch Med, Brigham & Womens Hosp, Vasc Med Res Unit, Cambridge, MA 02139 USA
[6] Coll France, F-75231 Paris, France