Child's brain. Coloured magnetic resonance imaging (MRI) scan of an coronal (vertical) section through the head and brain of a healthy 3-year-old child, passing through the ears. Seen here is the cerebrum, the largest part of the brain. It is divided into two hemispheres and is responsible for conscious thought, emotion and voluntary movement. Below centre is the cerebellum, a part of the brain that controls voluntary muscular movement and maintains posture and balance. The spine is seen at lower centre, with the shoulders at right and left.