1. Cell and Molecular Biology Unit, Institut Municipal d'Investigació Mèdica (IMIM), Dr Aiguader 88, Barcelona, Spain.
2. INSERM U846, Stem Cell and Brain Research Institute, Department of Stem Cells and Cortical Development, Bron Cedex, France.
3. Université de Lyon, Université Lyon I, Lyon, France.
4. Pompeu Fabra University, Dr Aiguader 88, Barcelona, Spain.