1 University of Oxford, Centre for Neural Circuits and Behaviour (CNCB), Tinsley Building , Mansfield Road, Oxford OX1 3SR, United Kingdom. Electronic address: tim.vogels@cncb.ox.ac.uk.
2 Brandeis University, Department of Biology, MS008, 415 South St., Waltham, MA 02454-9110, United States. Electronic address: griffith@brandeis.edu.