Body Clocks

Are you a morning person or a night owl? Whichever you are, your daily rhythm is determined by your circadian clock - powered by a small group of cells in the brain - and it tells you when to get up and when to sleep. Now Professor Bill Wisden and his team at Imperial College have discovered a second biological clock in the brain, located in a little cluster of nerve cells that produce a chemical called histamine, which helps to wake us up. Kat spoke to him to find out more about this molecular alarm clock.