Localized cochlear microphonics recorded from the spiral lamina

A greatly improved localization of the cochlear microphonic (CM) recording is obtained by the technique described in this report. CM tuning curves are obtained from the spiral lamina, immediately adjacent to the basilar membrane, when the first turn of the cochlear scala tympani is opened and drained. High-frequency slopes of −85 to −110 dB/octave are recorded, compared with the best slopes of only −30 dB/octave recorded by the differential electrode technique, and the tuning curves closely resemble published mechanical tuning curves for the basilar membrane. The technique should aid considerably the study of CM generator mechanisms. Subject Classification: [43]65.20, [43]65.40.