Mossy fibers are one of the major inputs to cerebellum. There are many sources of this pathway, the largest of which is the cerebral cortex, which sends input to the cerebellum via the pontocerebellar pathway. Other contributors include the

vestibular nerve The vestibular nerve is one of the two branches of the vestibulocochlear nerve (the cochlear nerve being the other). In humans the vestibular nerve transmits sensory information transmitted by vestibular hair cells located in the two otolith orga ...

and nuclei, the

spinal cord The spinal cord is a long, thin, tubular structure made up of nervous tissue, which extends from the medulla oblongata in the brainstem to the lumbar region of the vertebral column (backbone). The backbone encloses the central canal of the sp ...

, the reticular formation, and feedback from

deep cerebellar nuclei The cerebellum has four deep cerebellar nuclei embedded in the white matter in its center. 4 pairs of nuclei are embedded deep in the medullary centre, in the medial to lateral direction. They are fastigial nuclei, globose nuclei, emboliform nuc ...

. Axons enter the cerebellum via the middle and inferior cerebellar peduncles, where some branch to make contact with deep cerebellar nuclei. They ascend into the white matter of the cerebellum, where each axon branches to innervate

granule cells A granule is a large particle or grain. It can refer to: * Granule (cell biology), any of several submicroscopic structures, some with explicable origins, others noted only as cell type-specific features of unknown function ** Azurophilic granul ...

in several cerebellar

folia ''La Folía'' (Spanish), or ''Follies'' (English), also known as ''folies d'Espagne'' (French), ''La Follia'' (Italian), and ''Folia'' (Portuguese), is one of the oldest remembered European musical themes, or primary material, generally melodic, ...

. In this case, the pathway is so named for a unique synapse formed by its projections, the ''mossy fiber rosette''. Fine branches of the mossy fiber axons twist through the granule cell layer, and slight enlargements giving a knotted appearance indicate synaptic contacts. These contacts have the appearance of a classic Gray's type 1 synapse, indicating they are glutamatergic and excitatory. Sensory information relayed from the pons through the mossy fibers to the granule cells is then sent along the parallel fibers to the

Purkinje cells Purkinje cells, or Purkinje neurons, are a class of GABAergic inhibitory neurons located in the cerebellum. They are named after their discoverer, Czech anatomist Jan Evangelista Purkyně, who characterized the cells in 1839. Structure T ...

for processing. Extensive branching in white matter and synapses to granular cells ensures that input from a single mossy fiber axon will influence processing in a very large number of Purkinje cells.

References

* * {{Cerebellum Cerebellar connections

See also

References