SUPERIOR LARYNGEAL NERVE BRAIN-STEM EVOKED-RESPONSE IN THE CAT

The generator sources of each wave of the laryngeal brain stem evoked response (LBR) have yet to be precisely demonstrated, although this ha s been studied in several animal species. This study was carried out t o record the near-field brain stem activity as well as the far-field b rain stem activity in the cat under the same experimental setup, and t o search for the generator sources of the waves. Under general anesthe sia, the LBR tracings were recorded adjacent to and within the brain s tem following direct electrical stimulation of the internal branch of the superior laryngeal nerve. Reproducible positive and negative waves were detected by the far- and near-field techniques. Mean latencies, configurations, and reproducibility of each wave were demonstrated. Fr om these results, we speculate on the generator sources of each wave.