granule cell Granule cells are a class of small neurons found significantly in the cerebellum, olfactory bulb, and the dentate gyrus of the hippocampus in the human central nervous system. Their name derives from the presence of internal granular structures and they are one of the most abundant cell types in the entire brain, with estimates suggesting they likely comprise over half of all neurons. Due to their location, these cells play a vital role in the modulation of motor coordination, the olfactory system, and some aspects of memory and learning. Structurally, granule cells differ depending on their location. They have unmyelinated, very thin, T-shaped axons and a few short dendrites in the cerebellum. These dendrites receive information from a variety of sources, while their axons transmit the information to other parts of the brain. In granule cells of the cerebellum, the axons form parallel fibers that run into the molecular layer and synapse onto Purkinje cells, stellate, and basket cells, setting up a neuronal circuit critical for generating precise and fluid movements. Functionally, granule cells receive excitatory input from mossy fibers, which deliver sensory and motor information to the cerebellum, and this interaction is fundamental for the timing and coordination of body movements. In the olfactory bulb, granule cells process and modify olfactory information before passing it to the cerebral cortex, thereby aiding smell perception. Meanwhile, in the hippocampus, these cells participate in the formation and sorting of memories, particularly episodic memories. Due to their number, location, and function, the granule cells have a significant influence on cognition and behavior. (This extended description was generated by ChatGPT and reviewed by the CellGuide team, who added references, and by the CL editors, who approved it for inclusion in CL. It may contain information that applies only to some subtypes and species, and so should not be considered definitional.) ZFA:0009070 BTO:0003393 https://cellxgene.cziscience.com/cellguide/CL_0000120 A neuron of the vertebrate central nervous system that is small in size. This general class includes small neurons in the granular layer of the cerebellar cortex, cerebral cortex neurons that are not pyramidal cells and small neurons without axons found in the olfactory bulb. granule cell central nervous system neuron