Brain. Computer artwork of a section through a healthy brain. The front of the brain is at left. The highly folded area is the cerebrum, which is responsible for conscious thought, emotion and voluntary movement. At centre is a ventricle (cavity, yellow) which is filled with cerebrospinal fluid that cushions the brain. At bottom right is the cerebellum, which controls voluntary muscular movement and maintains posture and balance. To the left of the cerebellum is the brainstem, which controls subconscious functions such as breathing and the regulation of heart rate, and also connects the brain to the spinal cord.