They say that once you have learnt to ride a bicycle you never forget - and now neuroscientists at the University of Aberdeen have discovered why. Research published this month has identified a nerve cell in the brain that controls the formulation of memories for skills such as eating with chopsticks, skiing and riding a bike. When a person learns a new motor skill, the cerebellum assimilates the co-ordinated movement. The researchers discovered that one particular nerve cell - the molecular layer interneuron - acts as a gatekeeper that controls signals to the cerebellum. The findings may pave the way for advancements in prosthetics to mimic normal brain function for stroke victims and multiple sclerosis sufferers.