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.[1] They arise from the pontine nuclei as the second part of the corticopontocerebellar tract (the first part being the corticopontine fibers which synapse in the pontine nuclei), and decussate (cross-over) in the pons before passing through the middle cerebellar peduncles to reach and terminate in the contralateral posterior lobe of the cerebellum (neocerebellum). It is part of a pathway involved in the coordination of voluntary movements.[2]
| Pontocerebellar fibers | |
|---|---|
 Scheme showing the connections of the several parts of the brain. | |
| Details | |
| Identifiers | |
| Latin | fibrae pontocerebellares |
| NeuroNames | 1345 |
| TA98 | A14.1.05.110 |
| TA2 | 5849 |
| FMA | 75215 |
| Anatomical terms of neuroanatomy | |
The middle cerebellar peduncle consists entirely of pontocerebellar fibers and is the largest pathway of the cerebellum.[2]
Anatomy
editThe fibers are horizontally oriented, forming bundles which pass dorsally through the pons among the pontine nuclei and interweave with the perpendicularly oriented corticospinal fibers.[2]
Termination
editThe 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.[2]
Pathway
editThe entire pathway begins and ends in the cerebral cortex, and its entire course is the following:[2]
(Motor and sensory areas of) cerebral cortex → corticopontine fibers → (ipsilateral) nuclei pontis (synapse) → pontocerebellar fibers (decussation within pons) → middle cerebellar peduncle → (contralateral) (cerebellar cortex and (collaterals) dentate nucleus of) posterior lobe of cerebellum (synapse) → cerebellothalamic tract → superior cerebellar peduncle → mesencephalon (midbrain) (decussation of tract at level of inferior colliculus) → (ipsilateral) (ventral lateral nucleus of) thalamus → (ipsilateral) motor (cerebral) cortex (predominately premotor cortex and primary motor cortex)
Clinical significance
editDamage to the pontocerebellar fibers (or pontine nuclei) will result in contralateral ataxia: due to the double decussation of the pathway along its entire course, it terminates in the motor cortex of the same cerebral hemisphere in which it began; the motor lateral corticospinal tract then decussates once during its descent to control movement of the opposite side of the body.[2]
References
edit- ^ Rahman, Masum; Tadi, Prasanna (2024). "Neuroanatomy, Pons". StatPearls. StatPearls Publishing. Retrieved 11 August 2024.
- ^ a b c d e f Patestas, Maria A.; Gartner, Leslie P. (2016). A Textbook of Neuroanatomy (2nd ed.). Hoboken, New Jersey: Wiley-Blackwell. pp. 109–110, 113, 116, 292, 295–296. ISBN 978-1-118-67746-9.
External links
edit- https://web.archive.org/web/20130330093937/http://www.neuroanatomy.wisc.edu/virtualbrain/BrainStem/16Pontine.html
- https://web.archive.org/web/20080221222726/http://isc.temple.edu/neuroanatomy/lab/atlas/pmjdc/
- http://www.sylvius.com/index/p/pontocerebellar_fibers.html
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