Beth Stevens talks about the brain cells most people have never heard of, and suggests what they might have to teach us. Beth is a neuroscientist and associate professor at Harvard Medical School, who in 2015 was awarded a MacArthur Fellowship - the so-called 'genius grant' - for her work on microglial cells. In this talk she describes the connections between her research and her own family history, and explains why these cells - for so long overlooked in favour of neurons - may be the key to understanding much about the brain we don't yet know. Producer: Giles Edwards