Structure and function of the cerebellum

Introduction. The cerebellum is a neural structure, of a crystalline-like organization, present in all vertebrates. Its progressive growth from fishes to mammals, and particularly in primates, takes place following the repetition of a primitive cellular plan and connectivity. Development. The cerebellum is organized in folia located one behind the other in the rostrocaudal axis, and placed transversally on the brain stem. The cerebellar cortex has five types of neuron: Purkinje, stellate, basket, Golgi and granule cells. Apart from granule cells, the other cell types are inhibitory in nature. Afferent fibers to the cerebellar cortex are of two types (mossy and climbing) and carry information from somatosensory, vestibular, acoustic and visual origins, as well as from the cerebral cortex and other brain stem and spinal motor centers. The only neural output from the cerebellar cortex is represented by Purkinje axons that synapse on the underlying deep nuclei. Cerebellar nuclei send their axons towards many brain stem centers and, by thalamic relay nuclei, act on different cortical areas. Functionally, the cerebellum seems to be organized in small modules, similar in structure, but different in the origin and end of their afferent and efferent fibers. The cerebellum is involved in the coordination or integration of motor and cognitive processes. Conclusion. Although cerebellar lesion does not produce severe motor paralysis, loss of sensory inputs or definite deficits in cognitive functions, its certainly affects motor performance and specific perceptive and cognitive phenomena.