Figure 4. Morphological classification of monostratified RGC types in Brn3c^Cre/WT; Rosa26^tdTomato adult mouse retina.

(a–d) Flat mount perspectives of AAV FLEX-GFP infected retinas from Brn3c^Cre/WT; Rosa26^tdTomato mice. Images represent maximal projections of confocal stacks. Scale bar = 50 μm. (a1–d1) Corresponding reconstructions of cells a–d in en face (top) and vertical (bottom) projections. Scale bars in vertical projections represent the boundaries of the IPL and their horizontal arms are 25 μm. Axons are green, vitreal (ON) dendrites are blue, and scleral (OFF) dendrites are red. (e) RGC dendritic arbor parameters. Inner distance (ID) and outer distance (OD), normalized to the IPL thickness, define the boundaries of dendritic arbor stratification, and are set to 0 at the GCL and 1 at the INL. Arbor area of the bounding polygon is determined from the flat mount perspective. (f–i) Scatter grams of morphological parameters for monostratified RGC types. Gray shaded area indicates OFF layer. Black lines indicate ChAT bands. (f) Outer distance vs. inner distance relative to the normalized inner plexiform layer. (g) Dendritic arbor area vs. inner distance. (h) Area vs. dendritic arbor thickness. (i) Area vs. distance of cell body from optic disk. Proposed cell type assignments are colored and identified in the legend. The measurements for RGC examples identified in a–d are indicated by arrows in each scattergram.