Figure 7. Isodensity maps of retinal ganglion cells labeled with dextran tetramethylrhodamine and 10% hydroxystilbamidine methanesulfonate in control and experimental retinas. Retinal whole-mounts of representative adult albino Swiss mice are shown at different survival intervals after lasering the left eye and treating with dextran tetramethylrhodamine (DTMR) and 10% hydroxystilbamidine methanesulfonate (OHSt). To identify retinal ganglion cells (RGCs) capable of retrograde axonal transport, OHSt was applied to both superior colliculi 1 week before animal sacrifice, and to identify RGCs with a competent axon at the level of the optic nerve (ON) head, DTMR was applied to the ocular stump of the intraorbitally divided ON 2 days before sacrifice. These retinal whole-mounts illustrate typical topological distributions of OHSt⁺ RGCs and DTMR⁺ RGCs throughout these retinas. Note the close correspondence of the areas lacking backlabeled RGCs with both tracers for each illustrated retina. For all retinas, the dorsal pole is orientated at the 12 o’clock position (scale bar=1 mm). A-C: Whole-mount of a representative control right retina double-labeled with OHSt (A) applied 1 week before dissection and DTMR (B) applied 5 days later. An isodensity map of OHSt-labeled RGCs was constructed by splitting each frame into 36 parts and estimating RGC densities (C). Intensely labeled RGCs are distributed throughout the retina, but higher densities are present in a region along the naso-temporal axis of the superior retina, resembling a visual streak [69]. D-F: Whole-mounts of a representative experimental left retina from Group II (17 days after lasering) show the lack of OHSt-labeled RGCs (D) in a large sector that comprises the superior and small sectors of the inferior retina. Stained with DTMR (E), the same retinal sector shows few to no DTMR-labeled RGCs. An OHSt-labeled RGC isodensity map (F) illustrates the areas lacking backlabeled RGCs in a sector that spans almost from the 4 o’clock position to half past 8 o’clock. G-I: These whole-mounts of representative experimental retinas from Group III (35 days after lasering) show important diminutions in the numbers of OHSt-labeled RGCs (G) in all quadrants of the retina, except for the inferior-nasal. When stained with DTMR (H), the same retinal quadrants show few to no DTMR-labeled RGCs. The OHSt-labeled RGC isodensity map (I) illustrates the areas that lack backlabeled RGCs. J-L: Whole-mounts of a representative experimental retina from Group IV (63 days after lasering) show a lack of OHSt-labeled RGCs (J) mainly within the nasal retina and the superior-temporal quadrant. Stained with DTMR (K), the same retinal quadrants showed few to no DTMR-labeled RGCs. The OHSt-labeled RGC isodensity map (L) also illustrates the areas with focal loss of RGCs, as well as a small sector of the inferior temporal quadrant that shows diffuse loss of backlabeled RGCs.