The cerebellum is an intriguing component of the brain. In humans it occupies only 10% of the brain volume, yet has approximately 69 billion neurons; that is 80% of the nerve cells in the brain. The cerebellum first arose in jawed vertebrates such as sharks, and sharks in fact have an additional cerebellum-like structure that works as an adaptive filter. The function of shark cerebellum-like structures is to discriminate 'self' from 'other' in sensory inputs. With the evolution of the true cerebellum the adaptive filter functionality was adopted for motor control and paved the way for...