Antigenic compartmentation of the primate and tree shrew cerebellum: a common topography of zebrin II in Macaca mulatta and Tupaia belangeri.

Abstract

Despite the apparent uniformity in cellular composition of the adult cerebellar cortex, functional, anatomical, mutational and molecular maps all reveal a complex topography underlying the relatively simple architecture. In particular, zebrin II, a polypeptide antigen identified as aldolase C, is restricted to a subset of Purkinje cells that form a symmetrical and reproducible array of zones and stripes. The vermis of the well-studied rodent cerebellar cortex is divided into four transverse zones--anterior ( approximately lobules I-V), central ( approximately lobules VI and VII), posterior ( approximately lobule VIII) and nodular ( approximately lobules IX and X). Each transverse zone is further subdivided mediolaterally into parasagittal stripes. To gain insight into the evolution of cerebellar compartmentation, the pattern of zebrin II expression has been compared between the primate Macaca mulatta and the tree shrew Tupaia belangeri, and the results related to previous findings from other species. Although the somata of most Purkinje cells in the Macaca cerebellum express zebrin II, parasagittal stripes can still be delineated owing to the alternating high and low zebrin II immunoreactivity in the dendrites. In the macaque vermis, a complex set of zebrin II parasagittal compartments is found in all transverse zones. Unlike in rodents, in which uniform expression domains interrupt heterogeneous zones, zebrin II parasagittal stripes in the macaque cerebellum are seen throughout the vermis. In Tupaia, the parasagittal pattern of zebrin II expression also reveals a striking array of stripes in all lobules. The data suggest that cerebellar compartmentation in Tupaia belangeri more closely resembles that of primates than it does rodents or lagomorphs.