Figure 6

Many displaced ribbons remain paired with GluA2 puncta and/or ANF terminals, and most orphan ribbons remain near the IHC membrane. (a) Locations of orphan ribbons vs. synaptic ribbons for control vs. exposed ears (1–7 day post-exposure) at the 16 kHz location. Projections represent the following group sizes: Unexposed (n = 4 ears, 4 animals), 1 day (n = 4 ears, 3 animals), 1 week (n = 4 ears, 4 animals). As in Fig. 4, symbol size is proportional to ribbon volume (expressed re the median size for each stack), and color is used to distinguish orphan ribbons (unpaired with GluA2 puncta or ANF terminals) from ribbons paired with either GluA2 puncta or ANF terminals, as shown in the key. Pairing was assessed using custom software that creates a maximum projection of the voxel space within 2 microns of each ribbon in each z-stack¹⁹. (b,c) Confocal projections from a representative z-stack from the 16 kHz region at 1 day post-exposure, shown in the acquisition plane (x,y; c) and the perpendicular projection (z,y; b) that reveals the modiolar-pillar axis. Dashed box in (b) shows the z planes included in the xy projection in (c). Arrowhead in c points to the only CtBP2-positive punctum in this projection that does not appear to be at the IHC membrane.