Figure 5: Spatially-coincident astrocytes share morphological characteristics that suggest the presence of distinct microdomains of astrocyte reactivity. Threedimensional plots of spatially-coincident reactivity indices in young C57 (A), aged C57 (B), young DBA/2 (C) and aged DBA/2 (D) retina, where each data point represents measurements obtained from a single micrograph. For all graphs, reactivity indices are represented as: astrocytes/mm2 (y-axis), soma area (x-axis) and mean GFAP intensity/cell number (z-axis). (A) In young C57 retina, astrocytes exhibit similar morphological attributes across the population, with only some variability noted in GFAP intensity/cell (arrows). (B) In aged C57 retina, morphological attributes of spatially-coincident astrocytes become more variable, with distinct microdomains emerging with respect to density, GFAP intensity/cell (arrows) and soma area (arrowheads). (C) Young DBA/2 retina exhibits variability in morphological attributes in spatially-coincident astrocytes that is greater than that observed in young C57 retina, but less than that of aged C57 retina. Distinct microdomains appear with respect to density, GFAP intensity/cell (arrows) and soma area (arrowheads). (D) Aged DBA/2 retina exhibits the largest number and diversity of microdomains with significant variability in density, GFAP intensity/cell (arrows) and soma area (arrowheads).