An electrophysiological study of medullary neurons projecting to nucleus parabrachialis of the cat.

Neuronal activity was recorded from a total of 868 cells in the medulla of cats in regions known to project to nucleus parabrachialis (NPB) of the pons and thought to be involved in respiration. Of 196 neurons antidromically (85) or synaptically (111) activated from NPB, 178 were silent in the decerebrate or barbiturate-anesthetized preparation, and could not be induced to activity by increasing CO2, activating Breuer-Hering reflexes, stimulation of the vagus or vagotomy. We conclude that the direct pathway from the lateral tegmental field of the medulla to NPB is not significantly involved in respiratory function in these preparations.