Figure 4. Vertical analysis of the retina. A: Numerous green fluorescent protein (GFP)-positive ganglion, amacrine, and horizontal cells can be seen in the cryostat section of a retina after a light-exposed magnetic resonance imaging experiment. B: Nomarski image of the same region shown in (A) reveals the absence of photoreceptors. Abbreviations are as follows: INL represents inner nuclear layer; IPL represents inner plexiform layer; GCL represents ganglion cell layer. The scale bar is equal to 25 μm in A and B. C-D: Pseudocolor linearized average 1/T1 maps of the central retina from uninjected (C) and virus injected (D) eyes, scaled vertically to approximately match the boundaries of (A) and (B). The pseudocolor scale was blue to green to yellow to red, which represents lowest (0.56 s⁻¹) to highest (2.25 s⁻¹) 1/T₁ values. 1/T₁ is directly proportional to manganese concentration [16]. The vertical scale bar is equal to 130 μm, and the horizontal scale bar is 0.6 mm and applies to C and D.