FIG. 1.
Waveforms and manipulations used to measure cochlear responses (CRs) to low-frequency sounds. In this example, the sound was a 500-Hz, 65-dB SPL tone burst. A Average of responses to sounds of one phase. B Same as A, but waveform is from the inverted sounds. C CRdif waveform obtained by subtracting B from A. D CRave waveform obtained by averaging B and A. E Slow potential changes extracted from two-cycle smoothing of D. F The high-pass oscillating component of the CRave response obtained by subtracting E from D. Thick lines in C and F show the 20- to 30-ms regions where the amplitudes of the CRdif and CRave were measured, namely, CRdif,mid (pCM) and CRave,mid (pANOW), respectively. Hair cell currents are putatively the dominant origin for waveforms in A–C and auditory nerve action potentials for D–F. In the simplest identification, C is the cochlear microphonic (CM), E is a CAP, and F is the auditory nerve overlapped waveform (ANOW), but see the “DISCUSSION” for the limitations of these identifications.