About the size of a human fist, the cerebellum is the only branch of the brain between its inline division going from the spinal cord to the cerebral cortex. There is extensive folding of the thin, outer cortex into folia, and animals with more folia tend to have better motor coordination. A great mass of myeliniated axons (white matter), internal to the cortex, converge at the cerebellum core, the central medullary body. Within the core are a pair of deep cerebellar nuclei. The three layers of the cerebellar cortex are the inner granular layer (which contains mostly granular cells plus the cell bodies of Golgi cells), the middle Purkinje layer (which only contains Purkinje cells), and the outer molecular layer (which includes the stellate and basket cells).