1. Division of Physiology, Department of Experimental and Clinical Medicine, University of Florence, Viale G. Morgagni 63, Florence, Italy
2. European Laboratory for Non-Linear Spectroscopy (LENS), Via Nello Carrara 1, Sesto Fiorentino (FI), Italy
3. Division of Pharmacology, Department ‘NeuroFarBa’, University of Florence, Viale Pieraccini 6, Florence, Italy
4. National Institute of Optics, National Research Council (INO-CNR), Florence, Italy