Hair cell loss after noise exposure (Gerbil 63). Noise exposure was 120 dB SPL for 3 hours with a high-pass cutoff of 4 kHz. A, There is complete loss of hair cells and supporting cells in the organ of Corti extending from the base to the 3 asterisks. Partial hair cell loss extends beyond this to the 2 asterisks. From there, hair cells are preserved to the apex. B, Magnified view of complete hair cell loss. C, Magnified view of partial loss of inner and outer hair cells. D, Magnified view of apical zone, which contains a nearly normal complement of inner and outer hair cells.