Figure 3.
Differential transport loss with structural persistence in the superior colliculus (SC) of mice. The first two columns are cross-sections through the midbrain showing the superior colliculus. (A,B) Robust CTB and ERRβ label were evident in superficial SC of a control D2G mouse at 12 months of age. (C,D) are colorimetric reconstructions of the entire SC, warmer colors are denser with red representing 100% of the pixels at that location positive for either CTB (C) or ERRβ (D). As expected, this colliculus demonstrates a uniformly dense labeling across the entire SC. In aged DBA/2J mice, reductions in CTB label were often found (E,I; G,K). These deficits occurred in sectorial patterns, with some areas devoid of CTB (represented by blue) and some with strong label (right side of G). In DBA/2J mice up to 12 months of age, retinal ganglion cell (RGC) structural marker ERRβ appeared normal even in colliculi with severe CTB loss (F,J; H,L). In 13-month DBA/2J mice we saw significant loss of ERRβ label (N,P) along with absence of CTB label (M,O).