Recognition of propionic acid vapor after removal of the olfactory bulb area associated with high 2-DG uptake.

Rats were trained in an olfactometer to recognize the odor of propionic acid using a go, no-go operant discrimination tasks in which propionic acid vapor served as the negative stimulus and a series of novel odors served as positive stimuli. After training, rats readily responded to all novel odors but not to propionic acid. Removal of the olfactory bulb region previously identified with 2-deoxyglucose (2-DG) as being responsive to propionic acid had no effect on recognition of propionic acid, ability to discriminate novel odors from propionic acid or odor mixtures containing propionic acid or to discriminate propionic acid from a very similar odor (acetic acid). These results demonstrate that the 2-DG-identified propionic acid focal area is not essential for detection, discrimination or recognition of the odor. The outcomes are in accord with and extend those of other behavioral studies that have failed to demonstrate a functional correlate for the regional increases in metabolic activity produced by exposure to specific odors.