Chapters 5 - Motor systems 04. The role of the cerebellum

04. The role of the cerebellum

yellow-warning1Article automatically translated : We'll be reviewing and optimising it soon ...

The cerebellum (or small brain) plays an extremely important role in our life. It alone contains more than half of all the neurons in brain [ 54 ] with more than 50 billion neurons [ 159 ]!

1. Functions of the cerebellum:

The cerebellum plays an important role in voluntary movements, in posture, in maintaining the balance in the coordination of complex movements in their learning and many other recently highlighted including vegetative and cognitive-emotional roles [ 36 , 41 ].

Whatever the simplicity movement to achieve, the cerebellum is always there to control and coordinate. Without cerebellum, it would be impossible for us to walk or even stand up. It would be impossible to do the most simple things in life that require more or less a degree of precision, and without cerebellum we would be unable to learn to perform tasks of varying complexity.

2. Cerebellar cortex:

The cerebellar cortex is different from its counterpart brain, whereas the latter is made ​​up of layers of different cell number varying according to the cortical regions of up to 6 and thus delimiting the Brodmann areas, throughout the cerebellar cortex contains three cell layers [ 75 ], so no Brodmann areas in the cerebellum.

If the cerebellar cortex is unfolded, it is that its surface is about 75% of the cerebral cortex [ 4 ].

3. Purkinje cells:

All 50 billion of cerebellar cells, only Purkinje cells (which number around 15 million [ 3 ]) project outside the cerebellum [ 32 ] (0.03% of all cerebellar neurons).

Each Purkinje cell can have up to 300,000 synapses with other neurons [ 57 ] This shows the degree of integration is happening in the cerebellum [ 82 ].

Patients with cerebellar disease have similar clinical symptoms to those of an intoxicated person. In fact, alcohol is very toxic to Purkinje cells, which are the most valuable cerebellar cells.

4. Cerebellar pathways:

To provide these functions, the cerebellum must receive information of all kinds and almost all parts of the CNS. Thus, it receives proprioceptive information directly from the spinal cord and visual and vestibular original signals to balance the body. It also receives the most beams and central nuclei of the brainstem ganglia.

The cerebellum receives through the pons collateral relay from the fibers of the pyramidal tract [ 41 ], which enables it to constantly be aware of the movements to achieve and monitor their achievement As a whole sensory feedback including visual and proprioceptive.

The cerebellum therefore has all the information regarding the circumstances of the completion of the movement. From there, it assumes control of these movements by relay control loops ending on the primary motor cortex contralateral to join the pyramidal tract [ 41 ]. Because this route also crosses the midline, it is then that the cerebellar hemispheres ipsilateral motor control [ 5 ].

Chapters 5 - Motor systems 04. The role of the cerebellum