Olfactory Bulb Potentials Induced by Electrical Stimulation of the Nasal Mucosa in the Frog

The potential changes induced in the frog's olfactory nerve and bulb by electrical stimulation of the nasal mucosa have been studied. The response developed by the bulb is composed of two successive negative deflections. It has been possible to segregate these deflections and partly identify their origins. The first component of the response is of synaptic nature and builds up a persisting potential during repetitive stimulation. The second component of the response is sensitive to the action of narcotics and asphyxia and is blocked when secondary neurons are stimulated antidromically. The conclusion has been drawn that this component represents the propagated activity in neurons of secondary order. The properties of the olfactory nerve fibres have been studied in recordings of the nerve action potential.