Purkinje cell migration and differentiation

The Purkinje cell is the pivotal element of the cerebellar network, which integrates distinct extracerebellar inputs and generates the ultimate cortical output to be conveyed to the deep cerebellar nuclei. During development, the adult Purkinje cell phenotype is acquired through a complex sequence of ontogenetic processes, including migration from the ventricular neuroepithelium to the cortex, formation of the Purkinje cell plate and progressive arrangement into the final monolayer, axonal growth and expansion of the dendritic tree. Most of the distinctive features of Purkinje cells can be achieved even in dissociated cultures, suggesting that the acquisition of adult traits is regulated by the unfolding of a cell-autonomous program. On the other hand, the maturing Purkinje cells play a fundamental role in orchestrating the development of the entire cerebellum. Indeed, Purkinje cells are required for the genesis or the survival of different populations of cerebellar and extracerebellar neurons. They contribute to regulate the morphogenic processes leading to construct the cortical layering and network. They provide positional information to extracerebellar afferent systems, so to direct the topographic arrangement of projection maps. These phenomena and the underlying mechanisms will be described and discussed in the chapter, proposing that development of Purkinje cells is not just the acquisition of a mature neuronal phenotype, but is an essential organizational event of the whole cerebellar ontogenesis.