The Midbrain and Hindbrain (Brainstem)
The cerebellum, part of the hindbrain, is located under the occipital lobes and connects to the rest of the brain by tracts, or bundles of nerve fibers, which enter the brainstem. The cerebellum is responsible for equilibrium and the coordination of voluntary muscle activity. It also plays a role in the modulation of muscle tone, the amount of tension or resistance to movement in a muscle.
The midbrain and the hindbrain (pons and medulla oblongata less the cerebellum) are sometimes referred to collectively as the “brainstem”. The brainstem connects to the diencephalon at the top end, and the spinal cord at the tail end. The brainstem is responsible for basic bodily function such as breathing and heart rate. Through the brainstem pass all of the pathways that run between the spinal cord and the brain. These pathways carry messages to the brain and to the rest of the body to control movement and posture. Ten out of twelve cranial nerves also originate in and emerge from the brainstem. These nerves supply sensation and movement to the head and neck. If these pathways don’t work properly, it can result in a coma.