The deeper two layers of the cerebellar cortex, it contains the dark nuclei of the small densely packed neurons referred to as granule cells in addition to some Golgi type II cells in the cerebellar cortex. A notable feature of this layer is the presence of small spaces or islands termed cerebellar glomeruli where dendrites of granule cells and axon terminals of the Golgi cells form complex synaptic contacts called ‘rosettes’ with the endings of mossy fibers. It is distinguished in terms of an external and an internal granular layer. Once born, the granule neurons migrate from the exterior layer to form an inner layer (i.e., the internal granule layer). The external granular layer then ceases to exist in the mature cerebellum, leaving only granule cells in the internal layer. Furthermore, its dendrites synapse with incoming highly branched nerve fibers, but whose axons in turn form synapses with dendrites of Purkinje cells, basket cells, and stellate cells.
See Basket cells, Cerebellar cortex, Cerebellum (anatomy), Golgi type II cells, Granule cells, Molecular layer, Mossy fibers, Parallel fibers, Purkinje cell layer, Stellate cells