Cerebellum, light micrograph. The architecture of the cerebellum shows many folds, or folia, consisting of central cores of white matter axons (yellow) and the covering of grey matter of two layers (brown and yellow) containing neuron cell bodies and their nerve fibres. At 10% of the mass and 20% of the volume of the cerebrum, the cerebellar surface area is 75% of the cerebral cortex. Two types of grey matter neurons are notable. Purkinje neurons numbering some 15 million, are among the largest in size in the brain each with about 100,000 synapses. In the granular layer, there are more granular cell neurons, 60 billion, than all other neurons combined in the brain. Paraffin section, silver stain. Magnification: x6 when width printed at 10cm.