Neural Generators of Brainstem Evoked Potentials Results from Human Intracranial Recordings

Recordings were made from the auditory nerve near its entrance into the brainstem during neurosurgical operations for cranial nerve disorders. The recorded compound action potentials in response to 2000 Hz tonebursts at 90 dB were characterized by a negative peak with a latency of 3.0 to 3.7 ms. When these compound action potentials were compared with the brainstem evoked potentials (BSEP) recorded from the scalp during the operation or before the operation, it was found that the latency of the main peak of the compound action potential matched the latency of the vertex negative wave located between waves II and III (P2) and the potentials recorded from the nerve were found to match the N2P2N3 complex of the scalp-recorded BSEP. The results indicate that the auditory nerve is the neural generator of the two first peaks in the human BSEP, in contrast to the results of experiments in animals which show that the second peak originates in the cochlear nucleus.