The influence of inner hair cell loss on the instantaneous frequency of the cochlear microphonic.
The cochlear microphonic (CM) is produced by a change in standing currents during the motion of the cochlear partition. The motion of the partition and associated hair cell transduction processes are nonlinear and are reflected in the variation of the instantaneous frequency (IF) of the CM. Although the CM is dominated from receptor currents from outer hair cells (OHCs), receptor currents from inner hair cells (IHCs) may contribute to the fluctuation in the IF. In this paper we examine the influence of IHCs on the variation of the IF of the CM. A 75 mg/kg intraperitoneal (i.p.) dose of carboplatin reduced the IHC population by approximately 40%. The reduction in IHCs did not substantially affect the amplitude of the CM. The amplitude of the IF, however, was reduced at high signal levels (90 and 100 dB peak SPL). A phenomenological model of the CM indicated that the contribution of IHC receptor currents to the IF was small and that changes in OHC transducer characteristics may have a greater impact on the IF.
Chertoff
Mark E
ME
Department of Hearing and Speech, Kansas University Medical Center, 39th and Rainbow Blvd, Kansas City, KS 66160, USA. mchertof@kumc.edu
Amani-Taleshi
Darius
D
Guo
Yuqing
Y
Burkard
Robert
R
D000161:Acoustic Stimulation; D000818:Animals; D016190:Carboplatin / Q000494:pharmacology; D016923:Cell Death; D002682:Chinchilla; D003055:Cochlear Microphonic Potentials / Q000502:physiology*; D006199:Hair Cells, Auditory, Inner / Q000187:drug effects / Q000502:physiology*; D008954:Models, Biological
D016190:Carboplatin