The effects of electrically biasing the cochlear partition on the summating potentials were investigated in guinea pigs. The DIF (DIF = SV − ST) and AVE (2 AVE = SV + ST) SP responses were observed under polarization as well as the cochlear microphonics. These responses were recorded and the cochlear partition was polarized in the first and third turns; a wide range of stimulus parameters was utilized. The negative DIF and positive AVE components exhibited similar qualitative effects of electrical biasing as the (pure tone) CM, but the amount of change induced in the former responses was typically three or more times greater than that seen in the CM. While the DIF+ exhibited the opposite effects of polarization, compared to these responses, the results revealed an underlying relationship between the positive and negative DIF responses. As a rule, positive polarization currents caused the DIF responses to become less positive and more negative while the opposite was true for negative currents. No systematic level-dependent effects of electrical biasing were observed in the behavior of the negative DIF or positive AVE or in the positive DIF, given the complexities of its input-output function (without polarization). The results pertaining to the negative AVE component provided little basis for concrete conclusions concerning the effects of polarization on this component. The findings of this investigation reflect the involvement of electromechanical nonlinearities in the generation of the summating potentials.
ASJC Scopus subject areas
- Arts and Humanities (miscellaneous)
- Acoustics and Ultrasonics