Causes and consequences of structural aberrations in cerebellar development

The multitude of functions that are ascribed to the cerebellum has been growing steadily over the past decades. Despite the various functional domains, ranging from sensorimotor to emotion and cognition, the cerebellar structure is a phylogenetically conserved structure. The cerebellum comprises of a cortex and centrally located nuclei, which are organized in lobules and in functional modules. The main part of this chapter describes the development of the cerebellum and how cerebellar anatomy can be compromised during the earliest stages of life. Both intrinsic and extrinsic factors that affect the pre- and postnatal development of the cerebellum are reviewed. These include the causes and consequences of abnormal cerebellar neurogenesis and abnormal neuronal migration, synaptogenesis, and connectivity. Why is the developing cerebellum so vulnerable and why does injury to the developing cerebellum (e.g., cerebellar hemorrhages, which are relatively common as a complication of preterm birth) lead to such a major impact on nonmotor functioning, such as behavior. This chapter provides a concise literature overview that explains the answers to these important questions. Furthermore, we will highlight some important gaps in our current knowledge on abnormal cerebellar development, which will be important to solve in future studies to provide the basis for neuroprotective intervention trials.