Fig. 6. Region-specific loss of inner hair cells in the organ of Corti of 10-month-old Barhl1-null mice. Whole-mount organs of Corti from Barhl1^+/– (A,C,E) and Barhl1^–/– (B,D,F) mice were labeled with rhodamine-conjugated phalloidin. Compared with the heterozygote, no inner hair cells are present within the basal turn of the null mutant (E,F), many of them are missing from the middle turn (C,D), but the large majority of them still remain in the apical turn (A,B). The outer hair cells, however, appear to be entirely missing from the mutant organ of Corti (B,D,F). The arrow points to cell debris presumably resulting from degenerated supporting cells (F). AT, apical turn; BT, basal turn; IHC, inner hair cell; MT, middle turn; OHC, outer hair cell. Scale bar: 18.75 µm.