1. Institute for Complex Systems and Mathematical Biology and Department of Physics (SUPA), Old Aberdeen, Aberdeen AB24 3UE, United Kingdom
2. Max Planck Institut für Physik komplexer Systeme, Nöthnitzer Str. 38, 01187 Dresden, Germany
3. Laboratoire de Physique Théorique et Modélisation, Université de Cergy-Pontoise, CNRS, UMR 8089, 95302 Cergy-Pontoise cedex, France
4. Aix Marseille Univ, INSERM, INMED, and INS, Inst Neurosci Syst, 13000 Marseille, France
5. Istituto dei Sistemi Complessi, CNR - Consiglio Nazionale delle Ricerche, via Madonna del Piano 10, I-50019 Sesto Fiorentino, Italy