Fig. 4: GlyT2Cre ipRGCs account for the increased dorsal ipRGC density.
a Schematic of the retinal circuit with rod and cone photoreceptors located in the outer nuclear layer (ONL) and ipRGCs in the ganglion cell layer (GCL). Some of the six ipRGC types differ in their dendritic size and stratification in sublamina-a and sublamina-b. b, c Confocal micrographs of melanopsin antibody-stained ipRGCs illustrating M1 ipRGCs (asterisks) are identified by their dendrites transitioning from sublamina-b and branching in the sublamina-a of the IPL. Non-M1 ipRGcs branch earlier in sublamina-b (arrows). Disp displaced ipRGCs. d Neighbor density maps of morphologically identified M1 ipRGCs, e EGFP-positive M1 ipRGCs, f EGFP-negative M1 ipRGCs, and g EGFP-positive non-M1 ipRGCs. Each cell is color-coded according to the number of neighboring cells within a radius of 220 μm. Hotter-colored cells lie within regions of higher density, such as the dorsal retina for all M1 ipRGCs and the temporal retina for EGFP-negative M1 ipRGCs. The average density (±SEM magenta shading) at each retinal location along the dorso-ventral axis is plotted right (100 μm bins across the Y axis, n = 5 retina from n = 3 animals). h Bar graph of quantified M1 ipRGCs, EGFP-positive M1 ipRGCs, and sublamina-b stratifying EGFP-positive ipRGCs from whole-mount retinas (n = 5 retina from n = 3 animals). i Cells per hemisphere (n = 5 retina from n = 3 animals; ***p = 0.0002; ns p = 0.0535) and j density (dorsal vs. ventral) for morphologically identified M1 ipRGCs per 1 mm−2 across n = 7 dorsal regions and n = 9 ventral regions within n = 5 retina from n = 3 animals. k Distribution of average densities along the dorsal-ventral axis for M1 ipRGCs (left) and M1 ipRGCs minus EGFP-positive M1 ipRGCs (right; N = 5 retina from n = 3 animals). Magenta and blue curves are identical per plot but inverted across the optic nerve (ON) to visually compare the distribution of average densities in the dorsal and ventral regions n = 5 retina from n = 3 animals. Data were presented as mean values ± SEM. Statistical significance was assessed using one-way ANOVA using Å Ãdák’s multiple comparisons test. Scale bar in (b) and (c) = 50 µm. Source data are provided as a source data file.
