1. Department of Molecular and Cellular Neurobiology, Center of Neurogenomics and Cognitive Research, Faculty of Earth and Life Sciences, Vrije Universiteit, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands, Applied Biosystems, Lingley House, 120 Birchwood Boulevard, Warrington, Cheshire, WA3 7QH, Great Britain, and Leibniz Institute for Neurobiology, Department of Neurochemistry and Molecular Biology, Brenneckestr. 6, D-39118 Magdeburg, Germany