Cerebellum

A region of the brain behind the brainstem concerned with maintaining posture and balance and coordinating movement. The cerebellum is situated behind the brainstem and has 2 hemispheres. From the inner side of each hemisphere arise 3 nerve fibre stalks, which link up with different parts of the brainstem and carry signals between the cerebellum and the rest of the brain. Nerve fibres from these stalks fan out towards the deep folds of the cortex (outer part) of each brain hemisphere, which consists of layers of grey matter. Information about the body’s posture and the state of contraction or relaxation in its muscles is conveyed from muscle tendons and the labyrinth in the inner ear via the brainstem to the cerebellum. Working with the basal ganglia (nerve cell clusters deep within the brain), the cerebellum uses this data to fine tune messages sent to muscles from the motor cortex in the cerebrum.