A method for changing the avian endocochlear potential by current injection.

The endocochlear potential (EP) in the pigeon was found to be +10 +/- 3 mV. A method for changing the EP by current injection into the scala media is described. The EP change brought about was 1.6-2.9 mV/microA and was dependent on the distance from the tip of the current electrode. Single fiber activity in the cochlear ganglion could be recorded simultaneously with the current injection. These experiments have shown that decreases in the EP reduce the sound-evoked activity of primary afferent nerves and elevate their threshold.