1. European Laboratory for Non-Linear Spectroscopy, Via Nello Carrara 1, 50019 Sesto Fiorentino, Italy
2. Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Viale Gaetano Pieraccini 6, 50139 Florence, Italy
3. Interdepartmental Centre for the Study of Complex Dynamics, University of Florence, Via Giovanni Sansone 1, 50019 Sesto Fiorentino, Italy
4. Department of Physics and Astronomy, University of Florence, Via Giovanni Sansone 1, 50019 Sesto Fiorentino, Italy
5. National Institute of Optics, National Research Council, Via Nello Carrara 1, 50019 Sesto Fiorentino, Italy
6. Department of Biology, University of Florence, Via Madonna del Piano 6, 50019 Sesto Fiorentino, Italy