Title

Uniformity of cell distribution in the ganglion cell layer of prenatal cat retina: Implications for mechanisms of retinal development

Document Type

Journal Article

Publication Date

1-1-1981

Journal

Developmental Brain Research

Volume

2

Issue

2

DOI

10.1016/0165-3806(81)90034-1

Keywords

fetal retina; ganglion cell development; retinal development; retinal topography

Abstract

In an attempt to understand the ontogeny of the topography of the ganglion cell layer of the adult cat, we have studied the distribution of ganglion cells and their presumed percursor cells in pre- and postnatal retinas. Cell distribution was studied in whole-mounted, cresyl violet-stained retinas of fetuses of embryonic ages E47 and E57, of new-born animals, and of the adult. At E47 many cells, presumably the precursors of ganglion cells and of other neurones of the inner layers of the retina, have migrated from the germinative ventricular layer of the retina to the future ganglion cell layer. However, neither of the major features of the topography of the adult retina, the area centralis and visual streak, is apparent. The precursor cells are very numerous (our estimate is 860,000 as against about 116,250 ganglion cells in the adult retina), and apparently uniformly distributed. Their appearance is quite immature, with little cytoplasm evident. By E57, many cells have acquired granular cytoplasm and the area centralis and visual streak are clearly recognisable. Indeed, an 18:1 gradient in ganglion cell density has developed between central and peripheral retina, although the retina has only doubled in area. At birth the topography of the ganglion cell layer has matured considerably, although the number of cells identified as ganglion cells is higher than in the adult. These results suggest that an important mechanism in the development of the area centralis is a process of 'differential maturation' in which there is a marked variation between the area centralis and peripheral retina in the proportion of precursor cells which survive and mature as ganglion cells. The high number of ganglion cells in the neonatal retina suggests that this process continues into early postnatal life. A process of differential growth of the retina, suggested by earlier workers, seems also to contribute to the adult pattern of retinal topography. © 1981.

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