Comparison of Slow Potentials Evoked in the Frog's Nasal Mucosa and Olfactory Bulb by Natural Stimulation

Abstract

Abstract A comparative study has been made of the slow potential changes induced in the frog's olfactory bulb and nasal mucosa. It was found that the bulb response closely reproduced the slow potential changes in the receptor organ. Thus, changes in stimulus strength brought about identical changes in height of the two potentials. The response of the bulb was sensitive to asphyxia while the receptor response remained unaltered for hours after arrest of circulation. Antidromic stimulation of secondary olfactory pathways blocked the induced waves of the bulb but left the slow potential unaffected. Strong stimulation sometimes gave rise to oscillations superimposed upon the receptor potential. The frequency of the bulbar waves was not influenced by these oscillations. When the olfactory nerve was stimulated antidromically a diphasic spike potential could be recorded from the nasal mucosa. This potential exhibited the same distribution pattern as the receptor response. Repetitive maximal antidromic stimulation of the nerve did not affect the response evoked in the mucosa by natural stimulation.