Nonlinearities in cochlear receptor potentials and their origins.

Using intracellular recording methods in vivo [P. Dallos, J. Neurosci. 5, 1591-1608 (1985)], various nonlinear characteristics of receptor potentials from hair cells located in the low-frequency region of the guinea pig cochlea have been examined. Patterns of saturation for ac and dc response components obtained from Fourier analysis and directly from averaged waveforms are studied. Growth patterns of lower harmonic components are investigated and the interesting nonmonotonic properties of even harmonics noted. The latter are seen in both inner and outer hair cell responses, primarily with stimuli near the cells' best frequency. Fundamental ac and the dc potentials occasionally exhibit nonmonotonic growth. These patterns are studied and their occurrence in inner and outer hair cell responses considered.