1. Department
of Neurosciences, University of Parma, Via Volturno, 39, 43125 Parma, Italy
2. National Institute of Biostructures and Biosystems, Viale delle Medaglie d’Oro 305, 00136 Rome, Italy
3. Institute of Biophysics, CNR, /o
Area di Ricerca San Cataldo, Via G. Moruzzi N° 1, 56124 Pisa, Italy