Point 18











Cortico - Ponto - Cerebello - Thalamo- Cortical PathwaySuperior Cerebellar PeduncleThe majority of fibers that pass OUT of the cerebellum to the brain stem do so via the SUPERIOR CEREBELLAR PEDUNCLE. This peduncle is formed by axons that arise from certain deep cerebellar nuclei. These nuclei lie deep in the cerebellum. The "most famous" of these deep cerebellar nuclei resembles the inferior olive and is called the dentate nucleus (the remaining will be discussed later). This bundle passes rostrally into the dorsal pons where it forms a compact bundle along the dorsolateral wall of the fourth ventricle. At the level of the inferior colliculus all fibers of the superior cerebellar peduncle decussate. The majority of these crossed fibers ascend and either terminate in the red nucleus or continue rostrally to end within the MOTOR NUCLEI OF THE THALAMUS, the VENTRAL LATERAL and VENTRAL ANTERIOR nuclei. These thalamic nuclei project to motor-related cortical areas. Further details of the pathways connecting the cerebellar cortex with the brain stem and thalamus will be discussed during the lectures on the cerebellum.