Fig. 7. Progressive loss of cochlear hair cells along the longitudinal axis of the Barhl1^–/– organ of Corti. In the null mice, degeneration of cochlear hair cells follows two reciprocal longitudinal gradients – apical-to-basal for outer hair cells but basal-to-apical for inner hair cells. AVC, anterior vertical canal; Co, cochlea; HC, horizontal canal; IHC, inner hair cell; OHC, outer hair cell; PVC, posterior vertical canal; S, saccule; U, utricule.