Cerebellar connections - Physiology

This presentation discusses in brief about cerebellar connections from physiology point of view.

1. Cerebellar Connections Venkatesh Karthikeyan , I MBBS, VMCH & RI.

2. Connects Cerebellum to caudal midbrain and pons. Afferent fibres : Anterior spinocerebellar tract Tectocerebellar fibres Rubrocerebellar fibres Superior Cerebellar Peduncle Efferent fibres arises from: Cerebellar cortex Deep cerebellar nuclei

3. Connects Cererbellum to Pons Afferent: Pontocerebellar fibres Middle cerebellar Peduncle

4. Connects Cerebellum to medulla Afferent fibres : Dorsal spinocerebellar tract Cuneocerebellar tract Olivocerebellar tract Reticulocerebellar tract Vestibulocerebellar tract Inferior Cerebellar Peduncle

5. Afferent Connections Dorsal Spinocerebellar tract Ventral Spinocerebellar tract Olivocerebellar tract Vestibulocerebellar tract Cuneocerebellar tract Tectocerebellar tract Cortico - ponto -cerebellar tract Rubrocerebellar tract Reticulocerebellar tract

6. Dorsal Spinocerebellar Tract Carries unconscious kinesthetic and cutaneous afferents from the trunk and leg. Enters Ipsilateral inferior cerebellar peduncle . Distributed to anterior lobe, pyramid, uvula and median part of paramedian lobe

7. Ventral spinocerebellar tract Carries Cutaneous and proprioceptive fibers from all parts of the body. Enters the cerebellum via ipsilateral superior cerebellar peduncle. Distributed to vermis and anterior lobe.

8. Olivocerebellar tract Carries proprioceptive inputs from whole body. Relay in Inferior olive. Enters via inferior cerebellar peduncle to supply all parts of cerebellar cortex and deep cerebellar nuclei via climbing fibres . It is mainly a crossed pathway .

9. Vestibulocerebellar Tract Arises from vestibular nucleus. Fibers enter via Ipsilateral inferior cerebellar peduncle. Supplies Flocculonodular lobe and uvula.

10. Cuneocerebellar tract Carries proprioceptive impulses from arm and neck muscles. Arises in external arcuate nucleus. Enters through ipsilateral inferior cerebellar peduncle to anterior lobe, pyramid and uvula.

11. Tectocerebellar tract Arises from superior colliculi which relays fibres from eye. Also arises from inferior colliculi which relays fibres from ear. It enters via superior cerebellar peduncle to lobulus simplex, declive and tuber.

12. Rubrocerebellar tract Arises from the red nucleus Enters via superior cerebellar peduncle Distributed to mainly dentate nucleus. Transmits impulses which have originated from the cortex and relays in the red nucleus.

13. Cortico -Ponto-Cerebellar Tract Arises mainly from motor cortex . Ends in nuclei pontis . From nuclei pontis , the pontocerebellar fibres cross to enter the opposite side in the middle cerebellar peduncle. Distributed to all parts of Cerebellar cortex (except flocculonodular node).

14. Reticulocerebellar tract Arises in the lateral reticular nucleus and is uncrossed. Distributed via ipsilateral inferior cerebellar peduncle to whole of cerebellar cortex.

15. To brainstem To red nucleus and reticular formation To cerebral cortex Efferents from cerebellum

16. Vermis Fastigial Nucleus Medullary and Pontine regions of Brain Stem * This circuit is responsible is for controlling equilibrium and postural attitudes of the body.

17. Intermediate zone of cerebellum Interposed nuleus V entrolateral and V entroanterior nuclei of the thalamus Cerebral Cortex Thalamus Basal ganglia Red nucleus and reticular formation *Coordinates the reciprocals of agonist and antagonist muscles

18. C erebellar cortex of the lateral zone of the cerebellar hemisphere Dentate nucleus Ventrolateral and Ventroanterior nuclei of the thalamus Cerebral Cortex *Coordinate sequential motor activities initiated by the cerebral cortex.

19. Thank You  *Cerebellum has more neurons than the rest of the brain put together. * Cerebellum is the only part of whole brain, which receives enormous amount of information from the Cerebral Cortex with more than 40 million nerve fibres connecting the cerebellum.