Nat. Neurosci. 2, 642–648 (1999)

Because of an editorial error, the first sentence of the Results section on page 642 was incorrect. The sentence should read as follows:

Tone-evoked basilar membrane displacements were measured with a laser diode interferometer focused to a 5 μm spot with a depth of field of less than 2.3 μm, at up to 15 different locations across the width of the basilar membrane (Fig. 1c).