Illustration of the human cerebellum and brain- stem. At right, the highly convoluted surface of the cerebellum is seen, partly cut through to show its lobular structure. It attaches to the brain- stem at the swollen region of the pons (centre left). Beneath the pons is the medulla of the brainstem which narrows to the spinal cord. Above the pons is the midbrain area. Both the cerebellum and brainstem are primitive (evolutionary older) regions of the brain. They are concerned with in- voluntary, unconscious nerve control: cerebellum controls posture, balance and coordination; the brainstem controls heartbeat, breathing, digestion & blood pressure, facial expressions & blinking.