Purchase this article with an account.
J. D. Crook, B. Peterson, D. Dacey; Alpha-Like Ganglion Cells of the Primate Retina. Invest. Ophthalmol. Vis. Sci. 2007;48(13):5943.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
The morphological correlate of the cat alpha-Y ganglion cell has been described in a number of mammalian species but its correspondence in primate is uncertain. The prevailing view is that the magnocellular-projecting parasol ganglion cell type (also called the M-cell) corresponds to the cat alpha cell, though parasol cells (and the majority of cells of the magnocellular lateral geniculate nucleus (LGN) layers) are physiologically X-like. In this study we propose a newly identified low density ganglion cell type as an alternative candidate for the primate alpha cell.
The dendritic morphology of diverse ganglion cell types was determined by retrograde transport of biotinylated rhodamine dextran injected into either the LGN or the superior colliculus. Retrogradely labeled ganglion cell morphology was revealed in vitro by photodynamic staining and subsequent HRP histochemistry (Dacey et al., Neuron, 37(1):15-27, 2003).
Alpha-like ganglion cells show large cell bodies comparable to that of the parasol ganglion cells (alpha-like:16.9±2.5∝m diam., n=24 vs parasol:17.4±2.7∝m diam.; Watanabe and Rodieck; J.Comp.Neurol, 289(3):434-54, 1989). However alpha-like cells have thick primarydendrites, simple radiate dendritic branching and larger dendritic field diameters, about 1.5 times that of parasol cells at all retinal eccentricities (457.4±102∝m diam, n=24), and thus comprise ~3% of the total ganglion cell population. The alpha-like cells can also be divided into inner and outer cell populations that stratify at ~40 and 60% depths within the inner plexiform layer appearing to costratify with the inner and outer parasol cells. Alpha-like cells are consistently retrogradely labeled from tracer injections in the LGN and the superior colliculus.
The macaque alpha-like cell shows several morphological features characteristic of the cat alpha cell and is thus a viable candidate for a primate Y-cell physiological type. Measurements of the light response properties of the alpha-like cell can directly test this hypothesis.
This PDF is available to Subscribers Only