Olfactory Responses in the Gustatory Area of the Parabrachial Pons

Electrophysiological responses to olfactory and gustatory stimuli were recorded in the same neural elements in the parabrachial nuclei (PbN) of rats under Flaxedil. Responses to olfactory stimuli varied in temporal pattern and magnitude from responses to gustatory stimuli. Intravenous infusion of Nembutal while recording from one unit appeared to alter the pattern of responsiveness across stimuli. Most importantly the response to one olfactory stimulus (vanilla) was eliminated by this procedure. Olfactory-gustatory elements were located in the lateral portion of the taste-responsive area of the PbN, just below the brachium conjunctivum. These results suggest that the PbN receives input from both olfactory and gustatory pathways and that these pathways may converge on the same neural elements within the PbN. This convergence may be part of a neurophysiological substrate for the perception of flavor.