Granule cells are very small in comparison to stellate and pyramidal cells, but are the most numerous within the human brain at an estimated 10 billion cells.  Granule cells are located primarily in the somatosensory region of the neo-cortex, forming the first processing stage of the neo-cortex (similar to the cerebellum).  Axons of the granule cell arborize extensively, forming synaptic connections with multiple stellate cells.