Neurobiology of cochlear inner and outer hair cells: intracellular recordings

Recordings were made in the low-frequency region (third and fourth turns) of the guinea pig cochlea from both inner (IHC) and outer (OHC) hair cells. Certain electrical characteristics of these cells that have been described before (P. Dallos (1985) J. Neurosci. 5, 1591-1608) are reviewed. These are resting membrane potentials, response magnitude and saturation, and response phase. A comparison of sensitivity and best frequency is provided for IHCs and OHCs that are located in the same cochlear region. New data are presented for the level-dependence of response phase and for the properties of response asymmetry and the resulting dc component. The effects of intracellular polarizing current upon ac response magnitude are shown for both cell types.