Function of the cerebellum

Synonyms

Medical: Cerebellum (lat.)

English: cerebrellum

introduction

The fact that the cerebellum contains nerve cells in particular, which have an inhibitory effect, gives an idea of ​​its function. The cerebellum serves - to put it briefly at the beginning - to control movement sequences, primarily to limit movements so that they proceed in a regulated manner and do not become excessive.

Illustration brain

Cerebrum (1st - 6th) = endbrain -
Telencephalon (Cerembrum)

1. Frontal lobe - Frontal lobe
2. Parietal lobe - Parietal lobe
3. Occipital lobe -
   Occipital lobe
4. Temporal lobe -
   Temporal lobe
5. Bar - Corpus callosum
6. Lateral ventricle -
   Lateral ventricle
7. Midbrain - Mesencephalon
   Diencephalon (8th and 9th) -
   Diencephalon
8. Pituitary gland - Hypophysis
9. Third ventricle -
   Ventriculus tertius
10. Bridge - Pons
11. Cerebellum - Cerebellum
12. Midbrain aquifer -
    Aqueductus mesencephali
13. Fourth ventricle - Ventriculus quartus
14. Cerebellar hemisphere - Hemispherium cerebelli
15. Elongated Mark -
    Myelencephalon (Medulla oblongata)
16. Big cistern -
    Cisterna cerebellomedullaris posterior
17. Central canal (of the spinal cord) -
    Central canal
18. Spinal cord - Medulla spinalis
19. External cerebral water space -
    Subarachnoid space
    (leptomeningeum)
20. Optic nerve - Optic nerve
    
    Forebrain (Prosencephalon)
    = Cerebrum + diencephalon
    (1.-6. + 8.-9.)
    Hindbrain (Metencephalon)
    = Bridge + cerebellum (10th + 11th)
    Hindbrain (Rhombencephalon)
    = Bridge + cerebellum + elongated medulla
    (10. + 11. + 15)
    Brain stem (Truncus encephali)
    = Midbrain + bridge + elongated medulla
    (7. + 10. + 15.)

You can find an overview of all Dr-Gumpert images at: medical illustrations

Pontocerebellum

The Cerebral cortex (cerebral cortex) is responsible, among other things, for planning movements. It sends information to the Basal ganglia and - via a detour via the Bridge (pons) - the Cerebellumwho then fine-tune these movements and coordinate the muscle groups that will be involved in the movement. This happens both before and during the execution of the movement. For example, if you are grabbing a jam jar, constant feedback from the cerebellum and basal ganglia to the Coretx will ensure that at the end of the movement the hand has actually reached the jam jar and not the butter dish, which is 30 cm further to the left of it.

Vestibulocerebellum

The vestibular nuclei are the intermediate stations for information that comes from the Equilibrium organs (Vestibular organs: macular organ and semicircular canal organs, each in the Inner ear are to be found). Afferents from the vestibular nuclei into Cerebellum therefore serve to constantly compare the posture of the head with the current position of the body in space. In addition to coordinating head movement and posture, the cerebellum is also significantly involved in coordinating eye movements, which of course have to be coordinated with the position and movement of the head.

Spinocerebellum

Information about the position of joints and muscles (so-called propria = self and ception = perception) reaches the cerebellum from the spinal cord.In this way, the cerebellum “knows” at any time what position the body is currently in. For example, you can also tell with your eyes closed whether and in which direction you are moving a single finger.This is only possible because there are receptors in our joints, muscles and tendons that provide information about the position of their respective seat via the spinal cord pass on to the CNS.

Here the cerebellum has the task of adapting the holding and supporting motor skills (i.e. the body while standing and walking) to the respective situation.

All of this information reaches the cerebellum from the spinal cord, vestibular nuclei and cerebral cortex via so-called moss fibers that end at the granule cell layer. The granule cells are excited by these endings and now in turn excite the Purkinje cells (as already mentioned, the granule cells are the only excitatory nerve cells in the cerebellum, they use the neurotransmitter glutamate). Since the Purkinje cells have an inhibitory effect, this would mean that the Purkinje cells simply massively inhibit everything that they can achieve with their cell appendages. But that would not be helpful for the functionality of our motion sequences. And so the other inhibitory cell types in the cerebellum now come into play. Star cells, basket cells and Golgi cells have an inhibitory effect on the Purkinje cells in various ways (shown in simplified form in the diagram). What results from this is therefore an inhibition of inhibition, which means something like a certain but not too strong arousal. In order to understand what exactly is being excited in this way, one has to look at the upper part of the diagram. The cerebellum sends information to the spinal cord, vestibular nuclei and cerebral cortex via the Purkinje cells. To do exactly what was described above. Coordinating head and body posture, coordinating eye movements and directing movements in the exact direction and not choppy, but fine-tuning.

The cerebellum is essential to implicit learning. Well-trained movement sequences are “stored” in the cerebellum, so you no longer have to think while performing them. Think, for example, of cycling or driving, playing the piano and dancing.

Also read our article: motor learning