FIG. 1.

The normal afferent innervation of the inner hair cell (IHC). A Schematic illustrating two of the 15–20 unmyelinated cochlear nerve terminals (green) making synaptic contact with a single IHC. At each synapse, a pre-synaptic ribbon (red) is present within the IHC. When immunostained with anti-CtBP2 (as in Figs. 4 and 6), the IHC nucleus is also stained. The positions of pillar vs. modiolar sides of the IHC are shown. When viewed in the confocal as epithelial whole mounts, the x-, y-, and z-planes are oriented as shown. B An electron micrograph of a synaptic complex illustrating the pre-synaptic ribbon and its halo of synaptic vesicles within the IHC (modified from Liberman 1980).