Bill Richardson is Professor of Biology at UCL. He has made major contributions to glial cell biology. He identified platelet-derived growth factor (PDGF) as an essential mitogen for oligodendrocyte development and normal myelination in vivo. This implied that the PDGF pathway may be a useful therapeutic target in demyelinating diseases like multiple sclerosis. Bill showed that oligodendrocyte development and myelination continues throughout adulthood, raising intriguing questions about the functions of late-myelinating axons. He is now combining mouse genetics and behavioural analyses to study the role of myelin formation in motor learning and memory.