Zones and stripes: Development of cerebellar topography

Abstract

Cerebellar architecture is organized around the Purkinje cell. Purkinje cells in the mouse cerebellum come in many different subtypes, organized first into four transverse zones and then further grouped into hundreds of reproducible topographical units - stripes. Stripes are identified by their functional properties, connectivity, and expression profiles. The molecular pattern of stripes is highly reproducible between individuals and conserved through evolution. Pattern formation in the cerebellar cortex is a multistage process that begins with the generation of the Purkinje cells in the ventricular zone (VZ) of the fourth ventricle. During this stage or shortly after, Purkinje cell subtypes are specified toward specific positions. Purkinje cells migrate from the VZ to form an array of clusters that form the framework for cerebellar topography. At around birth these clusters disperse, triggered by a Reelin signaling pathway, to form the adult stripe array. The chapter will begin with a brief overview of adult cerebellar topography, primarily focusing on the mouse cerebellum, and then discuss the cellular and molecular mechanisms that establish these remarkable patterns.