A. Surface preparation from the apical turn of an Ly 5.1 mouse stained with NF 200. NF 200 positive nerve processes project to both inner (IHC) and outer (OHC) hair cells. Note that unmyelinated nerve processes distal to the habenula perforata (white dashed line) were labeled, whereas myelinated nerve fibers within the osl, proximal to the habenula perforata, were unlabeled. NF 200 positive fibers include large terminals (arrowheads) under IHCs, the inner spiral bundle (isb), the tunnel spiral bundle (tsb), the tunnel radial bundle (trb) and the outer spiral bundle (osb). B–D. Surface preparations from the apical, middle and basal turns of an Ly5.1 mouse stained with myosin VIIA. Almost all IHCs and OHCs were intact. E. Mean cochleograms from C57BL/6J and Ly 5.1 mice. Very little OHC loss was seen in either strain. Data presented as mean ± standard error of the mean (SEM) (n=5 per group). A magenta-green copy of this figure is available as Supplementary Figure 6. Scale bars: A, 15 µm; B–D, 20 µm.