Relation Between the Waveform of the Cochlear Whole Nerve Action Potential and Its Intensity Function

Abstract

The whole-nerve action potential (AP) was recorded by intracochlear electrodes in the guinea-pig. As is well known, in normal conditions, the AP elicited by tone bursts displays negative and positive deflections. In-activation of the central end of the nerve at the internal auditory meatus (IAM), by introduction of a few drops of KG solution, or by mechanical pressure, produces a change in the wave shape of the AP which is transformed into a single negative deflection. The relation of the amplitude of the monophasic AP to the intensity of the tone burst is monotonic, in contrast to the classical two-slope variation observed in normal conditions. These results are interpreted by the disappearance of a positive component of the response produced at the IAM. The convolution of the monophasic unit AP would explain the monotonic intensity function.