Fig. 7. Basal turn cochlear innervation at P7 in wild-type and B/N mice. A collapsed z-series of confocal images shows the radial fibers (RF) extending to the inner hair cells (IHC) and outer hair cells (OHC) in the control animal (A). The innervation of the outer hair cells is less well organized in the organ of Corti in mutant animals (C) and additional fibers can be seen running underneath the organ of Corti in a separate bundle (* in B) and between the radial fibers (^ in B). None of these fibers exists in control animals. Radial sections reveal the presence of longitudinally cut radial fibers in the control animals (D) and additional transversally cut spiraling fiber bundles (^,*) below the organ of Corti among the tympanic border cells in the mutant mice (E). These fibers may be myelinated (^ in E). Immunohistochemistry (red) for acetylated tubulin (F,G) can visualize these fibers only in the mutant (^,* in G). Scale bar: 10 µm.