ACTIVITY ELICITED IN THE AUDITORY PATHWAY OF THE RAT BY ELECTRICAL-STIMULATION OF THE COCHLEA

The activity elicited by electrical stimulation of the cochlea in the auditory pathway was assessed in an animal model of cochlear implants on the basis of the induction of the immediate early gene c-fos and si ngle neuron recordings. Electrical stimulation of the cochlea induced Fos-like immunoreactivity in the cochlear nucleus, mainly in its dorsa l nucleus, in the superior olivary complex, in the lateral lemniscus, but not in the central nucleus of the inferior colliculus, the main re lay nucleus in the auditory midbrain. However, single unit recordings from the inferior colliculus, ipsilateral and contralateral to the ele ctrically stimulated cochlea, showed clear responses of single neurons , reminiscent of those elicited by acoustic stimulation. These finding s provide immunocytochemical and electrophysiological evidence that th e various nuclei of the auditory pathway are activated by electrical s timulation of the cochlea.