[1] Karolinska Inst, Nobel Inst Neurophysiol, Dept Neurosci, SE-17177 Stockholm, Sweden
[2] Moscow MV Lomonosov State Univ, AN Belozersky Inst Physicochem Biol, Moscow 119899, Russia
[3] Univ Calif San Diego, Inst Nonlinear Sci, La Jolla, CA 92093 USA
[4] Russian Acad Sci, Inst Informat Transmiss Problems, Moscow 101447, Russia