Figure 3

Reduction of innervation of the ear is shown in 8-day old mice. While all vestibular sensory epithelia retain some afferent (a) and efferent (b) innervation, there is a more pronounced reduction, in particular of efferent fibers, to the utricle (a,b) as compared to the canals. In the cochlea there is an increased spacing between radial fiber bundles in the basal turn (c,e). No afferents can be traced to the three outer spiral bundles along outer hair cells of mutant littermates (c, e). The apex shows little change, except for the absence of fibers to the area of outer hair cells and the formation of inner spiral bundles passing along the few immature hair cells (d,f,g). The pattern obtained with DiI tracing is identical to that obtained by acetylated tubulin immunoreactivity (f,g). Bar indicates 1000 μm in a, 100 μm in b-g.