Abstract
The sense of olfaction can be thought of as consisting of two distinct sub-modalities: orthonasal (perception of odorants that enter the nose through the nostrils) and retronasal (perception of odorants that are present in the mouth and that reach the nasal cavity from the back of the throat). Researchers in the Katz lab have proposed that retronasal olfaction should share properties with taste; recent testing has confirmed that, like taste preference learning, retronasal learning is: 1) more rapid than orthonasal learning; and 2) dependent on taste cortex. This research has used odorants dissolved in water to isolate retronasal stimuli, which theoretically, should differ from pure water only with regard to odor, but which conceivably could contain taste and mouth feel components. In order to ensure that the observed preferences were learned only to odor, it is therefore necessary to render rats anosmic, and then to repeat these tests with the anosmic rats. Here, I began this set of studies, by first establishing orthonasal (i.e., purely olfactory) preferences to an odor, then rendering rats anosmic via deciliation, and then attempting to confirm that the procedure rendered the rats anosmic—my prediction is that the orthonasal preference would be lost. My data did reveal a decline in preference to chance (50%) levels in deciliated animals; unfortunately, this same decrease was also observed in control (anesthesia-only) animals. This suggests that there may have been one of several possible failures in the behavior paradigm for control rats, a failure that made me run out of time before I was able to conduct a test similar to that of previous studies. In the discussion, I explore next steps, and the implications for this research in regard to the current literature on olfaction.