[1] Univ Freiburg, Bernstein Ctr Computat Neurosci Freiburg, Fac Biol, D-79104 Freiburg, Germany
[2] Swiss Fed Inst Technol, Bio Engn Lab, Dept Biosyst Sci & Engn, CH-4058 Basel, Switzerland
[3] Univ Freiburg, Dept Microsyst Engn, Fac Sci Appl, D-79110 Freiburg, Germany