Pontocerebellar fibers
The pontocerebellar fibers are the second-order neuron fibers of the corticopontocerebellar tracts that cross to the other side of the pons and run within the middle cerebellar peduncles, from the pons to the contralateral cerebellum.
They arise from the pontine nuclei as the second part of the corticopontocerebellar tract, and decussate in the pons before passing through the middle cerebellar peduncles to reach and terminate in the contralateral posterior lobe of the cerebellum. It is part of a pathway involved in the coordination of voluntary movements.
The middle cerebellar peduncle consists entirely of pontocerebellar fibers and is the largest pathway of the cerebellum.
Anatomy
The fibers are horizontally oriented, forming bundles which pass dorsally through the pons among the pontine nuclei and interweave with the perpendicularly oriented corticospinal fibers.Termination
The pontocerebellar fibers terminate throughout the cerebellar cortex except the flocculonodular lobe in an arrangement corresponding to the cortical origin of the pathway: efferents of the primary motor cortex project to the vermis and paravermal zone; efferents of the premotor, somatosensory, and association cortex project to the cerebellar hemisphere cortex. Additionally, the fibers also issue collaterals to the dentate nucleus.Pathway
The entire pathway begins and ends in the cerebral cortex, and its entire course is the following:cerebral cortex → corticopontine fibers → nuclei pontis → pontocerebellar fibers → middle cerebellar peduncle → posterior lobe of cerebellum → cerebellothalamic tract → superior cerebellar peduncle → mesencephalon (midbrain) → thalamus → motor (cerebral) cortex