Cerebellum anatomy. Light micrograph of a cross- section through cortex and medulla of the human cerebellum. The highly folded cerebellum of the hindbrain contains white matter at its core, known as the medulla, seen at lower right. White matter consists of axon nerve fibres. External to this is the folded cortex (brown) made of two layers. Next to the medulla is the granular layer of the cortex (brown, dotted) packed with nerve cells. A thicker molecular layer (red brown) is rich in dendrites, nerve fibre networks. Purkinje cells (black) occur between these cortical layers. The cerebellum controls body posture, coordinates muscle movement and balance. Magnification: x14 at 4x5 inch size.