File:Midsaggittal diagram of the human cerebellum.png

English: Midsaggittal diagram of the human cerebellum and its constituent layers during perinatal development. The outermost layer of the cerebellum is the transient external granule layer (EGL), which is composed of an outer germinal matrix populated by neural progenitor cells (EGLO; dark spheres) and an inner layer (EGLI; white spheres) where newly formed granule cell neurons congregate and mature. After a short time, these granule cells then migrate (white spheres with arrows) past the molecular (ML) and Purkinje cell layers (PCL) before becoming incorporated into the internal granule layer (IGL), which lies superficial to the cerebellar white matter (WM). After birth, the EGL begins to disappear as its job of producing new neurons ends, and the cerebellum transitions into a more adult state. Insets (right) reflect magnified views of boxed regions (left).