1. Centre for Neural Circuits and Behaviour, University of Oxford, Oxford OX1 3SR, U.K., and Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland, friedemann.zenke@fmi.ch
2. Centre for Neural Circuits and Behaviour, University of Oxford, Oxford OX1 3SR, U.K., and Institute for Science and Technology, 3400 Klosterneuburg, Austria, tim.vogels@ist.ac.at