1. A. Riehle, Center for Research in Cognitive Neuroscience, CNRS, 31 Chemin Joseph Aiguier, 13402 Marseille Cx 20, France.
2. S. Grün, Department of Physiology, The Hebrew University, Hadassah Medical School, Jerusalem 91120, Israel.
3. M. Diesmann and A. Aertsen, Department of Neurobiology and Biophysics, Institute of Biology III, Albert-Ludwigs-University, Schänzlestrasse 1, D-79104 Freiburg, Germany.and