Abstract
Purpose :
In primate retina around 20 morphological types have been distinguished based on the shape and size of their dendritic tree and their projection to higher brain areas (Rodieck and Watanabe, 1993, J. Comp. Neurol; Dacey, 2004, The Cognitive Neurosciences; Yamada et al. 2005, Vis. Neurosci.; Crook et al., 2008a,b, J. Neurosci.; Szmajda et al., 2008, J. Comp. Neurol.; Ivanova et al., 2010, IOVS; Moritoh et al., 2013, PlosOne). The exact proportions of the specific cell types, however, are not known. Here we characterized the ganglion cell types across the retina of the marmoset.
Methods :
Quadrants of adult marmoset retinas were mounted ganglion cell side up onto filter paper and then transfected via particle-mediated transfer using expression plasmid for the postsynaptic density 95-green fluorescent protein (PSD95-GFP). The retinas were cultured in Ames’ medium in an incubator for 3 days, then fixed and processed with immunohistochemical markers. Labeled cells were classified based on eccentricity, dendritic field size and shape, and stratification depth in the inner plexiform layer.
Results :
In total over 580 ganglion cells were identified in three retinas. In accordance with the classification of Dacey (2004) we distinguished inner and outer midget, inner and outer parasol, broad thorny; small bistratified; large bistratified; recursive bistratified, recursive monostratified, outer and inner narrow thorny; smooth monostratified; large sparse cells and inner and outer giant (melanopsin) ganglion cells. Broad thorny cells made up 44% of the widefield cell population. In addition, low numbers of cells resembling ganglion cell types projecting to the superior colliculus and pretectum were identified. In central retina midget ganglion cells made up at least 46%; parasol cells made up 20% and widefield cells 34%. In peripheral retina the proportion of midget and parasol cells decreased to 37% and 15%, respectively, whereas the proportion of widefield cells increased to 48%.
Conclusions :
Particle mediated gene-transfer allows the identification of at least 15 types of ganglion cell in marmoset retina. The proportion of widefield ganglion cell types increases with distance from the fovea.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.