Rats with one olfactory bulb removed and the contralateral naris closed can detect odors.

Rats with one olfactory bulb removed were trained to detect 0.5%-0.005% concentrations of amyl acetate. These rats had only a slight decrement in performance when the naris ipsilateral to the intact olfactory bulb was closed. Thus, vapors inhaled through one naris can stimulate olfactory receptor neurons in the contralateral nasal vault. This internasal stimulation is probably mediated by the nasopharyngeal canal or nasopharynx.