Fig. 5. Abnormal afferent fiber projections in the semicircular canals of Brn3a^-/- mice. (A,B) DiI-labeled flat mount of E13.5 inner ears shows a dramatic reduction in fiber projection to the posterior vertical canal (pvc) and the cochlea in Brn3a^-/- embryos. Although slightly reduced, the innervation to the anterior vertical canal (avc), horizontal canal (hc) and utricle (u) in Brn3a^-/- mice is comparable with that in the wild type. (C,D) In contrast to the dense innervation in the wild type, the posterior vertical canal of Brn3a^-/- mice shows essentially no innervation at P0. Scale bars: 200 µm.