Abstract
The acoustic far-field response (FFR) was observed in Kanamycin-treated guinea pigs from silvere wire electrodes chronically implanted in the epidural space of the temporal site. Binaural interaction was also checked by unilateral destruction of the anesthetized animal's cochlea. The early components of FFR, i.e., cochlear microphonics (CM) and a part of cochlear action potentials (AP) recorded from the temporal site were mainly contributed by the cochlea homolateral to the recording site. Later components, i.e., the brain stem responses, (BSR) and early phase of cortical evoked potentials (EP), were affected bilaterally and showed complex characteristics. Kanamycin was injected subcutaneously (400mg/kg) daily. CM disappeared primarily while the other neural responses persisted. EP was the last to be recorded. Abrupt decrease in amplitude of the responses of more than 80dB within 2 days occurred approximately 2 weeks later. The bioelectric correlates may suggest that CM is generated at the hair cells and plays a significant role in the hearing process.
