Figure 4. Radial section of cochlea showing missing IHC, but intact nerve fibers in the habenula perforata. (A) Toluidine stained radial section (3 μM) from the middle turn of an Epon embedded cochlea from a 9-month-old dwg/dwg mouse stained with toluidine blue. Stria vascularis (StV), scala vestibuli (SV), scala media (SM),scala tympani (ST), organ of Corti (OC), nerve fibers (NF) and spiral ganglion neurons (SGN). Inset shows higher magnification view of OC with three rows of OHC, inner pillar cell (IPC), outer pillar cell (OPC), but missing IHC. Dashed red line shows approximate plane of section through the habenula perforata (HP). (B) Toluidine stained section (3 μM) tangential to the habenula perforata. Habenular openings densely packed with nerve fibers.