DEVELOPMENT

 

The cerebellum derives from the rostral portion of the rhombencephalon, called the metencephalon. During the development, two dorsal growths (rhombic lips) develop in the metencephalic alar plate. They expand to meet and fuse in the midline.

 

As a result of the deepening of the pontine flexure, the fussed rhombic lips are compressed in the rostrocaudal direction and form the cerebellar plate with a middle line or vermis and two lateral portions or hemispheres. Due to the vermis develops latter that the hemispheres, it is most likely to be absent or underdeveloped that other parts of the cerebellum.

 

Neuroepithelial cells from the rhombic lips migrate to the top of the roof of the fourth ventricle and form the mantle layer. From this layer, the same cells migrate towards the surface and give rise to a cortical layer. Then, cells from the cortical layer descend and form the granular and Golgi cells, giving room on the surface for the molecular layer to form. At the same time, some mantle cells ascend to form the Purkinje cells. Their dendrites make up a major portion of the molecular layer and their axons are directed deeply toward the cerebellar nuclei (which are derived from mantle cells that have not been displaced) and vestibular nuclei.

 

Once granule cells start to differentiate, they bind to astroglial cells via neuroglia-adhesion systems and commence their migration along the glial guides. The formation of neural layers uses a system of radial glial fibers for the migration of young neurons from their site of origin to their final location.