Transection of the lateral olfactory tract does not produce anosmia

Rats trained in an olfactometer were tested for retention of an odor detection and odor discrimination task after lesions of the olfactory peduncle. Large lesions of the peduncle, including transection of the lateral olfactory tract and anterior commissure resulted in severe deficits in retention and relearning but did not produce anosmia. Discrete lesions of the lateral olfactory tract had little or no effect on retention. The results indicate that the lateral and intermediate olfactory pathways are not essential for smell and suggest that significant olfactory function may be mediated by medial olfactory bulb projections.