Evidence of early topographic organization in the embryonic olivocerebellar projection: A model system for the study of pattern formation processes in the central nervous system

Abstract

Many projection systems within the peripheral and central nervous system are topographically organized, and it has become increasinging clear that interactions which occur during development determine the projection patterns these systems exhibit in the adult. The olivocerebellar system was chosen as a model system for this study of afferent pattern formation because it has several characteristics which lend themselves to a study of this type. Applications of horseradish peroxidase were made to both the cerebellar primordium and to the inferior olive of embryonic and neonatal mice using an in vitro perfusion system to support the tissue during the transport period. Fibers labeled after restricted olivary applications are limited to particular mediolateral regions of the cerebellum. Similarly, olivary cells retrogradely labeled after discrete cerebellar applications are restricted to particular olivary subdivisions. The results indicate that the olivocerebellar projection displays elements of topographic organization as early as El5 and that the pattern displayed is roughly comparable to that of the adult mammal. The observed trajectories of olivocerebellar fibers and their concomitant association with both Purkinje and cerebellar nuclear cells during embryonic development suggests a role for either or both cell types in the pattern formation process. 0 1993 Wiley-Liss, Inc.

Reestablishment of the olivocerebellar projection map by compensatory transcommissural reinnervation following unilateral transection of the inferior cerebellar peduncle in the newborn rat

“…Phenotypically heterogeneous subpopulations of Purkinje and inferior olivary neurons are independently generated by intrinsic genetic programs (Wassef and Sotelo, 1984;Wassef et al, 1990Wassef et al, , 1992aOberdick et al, 1993;Millen et al, 1995) and a similar phenomenon likely occurs also in the deep nuclei (Chédotal et al, 1996). The basic organisation of the olivocerebellar projection is already achieved before any contact with target neurons is established through the selective segregation of ingrowing olivocerebellar axon subsets Chédotal and Sotelo, 1992;Paradies and Eisenman, 1993). Then, reciprocal recognition by phenotypically distinct subpopulations of afferent axons and target neurons in the cerebellar cortex and deep nuclei underlies the formation of the topographically arranged olivo-cortico-nuclear loops which subserve cerebellar function (Lliná s and Welsh, 1993).…”

Correspondence between L7-lacZ-expressing purkinje cells and labeled olivocerebellar fibers during late embryogenesis in the mouse

“…Several of the PC-specific markers which are expressed heterogeneously during cerebellar development are not upregulated until late in embryonic development or after birth. By this time the basic parasagittal organization of at least one afferent, the olivocerebellar (OC) projection, is already established (Paradies and Eisenman, 1993). In addition, until recently it has been technically difficult to evaluate the spatial relationship between particular subsets of afferent fibers and specific groups of PC.…”

“…The location of labeled olivocerebellar fiber terminals originating from the caudal medial accessory olive (cMA0) was compared to the mediolateral positions of groups of L7llacZ+ PC at E17118, the earliest developmental time when P-galactosidase (Pgal) activity can be visualized using X-gal histochemistry. The cMAO projection was selected for comparison to the L7llacZ expression pattern because previous studies had demonstrated that, as in the adult, the embryonic cMA0 projects almost exclusively to the contralateral medial cerebellar cortex (Paradies and Eisenman, 1993). Because L7ilacZ is upregulated first in medial cerebellar regions, the projection from the cMAO was considered the most likely to overlap or colocalize with these populations of labeled cells.…”

In vivo analysis of Purkinje cell firing properties during postnatal mouse development

“…These processes include lobule formation, zonal patterning of zebra-striped compartments, and climbing fiber synaptogenesis. In mice, climbing fiber and mossy fiber afferents have already invaded the cerebellum by around embryonic days 13/14 (Grishkat and Eisenman 1995;Paradies and Eisenman 1993). Later, in the cerebellum of older embryos and newborn pups, multiple climbing fibers innervate a single Purkinje cell.…”