Evidence for electrically evoked travelling waves in the guinea pig cochlea.

Electrically evoked compound action potentials (EECAP) were produced by the injection of pulsed sinusoidal current through metal electrodes into the basal turn. Plots of current threshold against frequency closely resembled conventional compound action potentials (CAP) audiograms for frequencies represented apically of the electrode location. EECAPs were masked by sound and CAPs were masked by current in a manner consistent with the generation of a propagated travelling wave.