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 has been studied in several animal species. This study was carried out to record the near-field brain stem activity as well as the far-field brain stem activity in the cat under the same experimental setup, and to search for the generator sources of the waves. Under general anesthesia, the LBR tracings were recorded adjacent to and within the brain stem 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. From these results, we speculate on the generator sources of each wave.