RECURRENT INHIBITION IN THE OLFACTORY BULB: I. EFFECTS OF ANTIDROMIC STIMULATION OF THE LATERAL OLFACTORY TRACT

Abstract

Anti-dromic stimulation of the rabbit''s lateral olfactory tract following chronic isolation of the olfactory bulb by transection of the olfactory peduncle inhibits spontaneous discharge of virtually all types of neuron in the olfactory bulb. This effect is cumulative with repeated stimulation and can then even block the antidromic invasion of the mitral cell soma. Evidence is advanced to support the belief that this recurrent inhibition is due to the direct action of mitral neuron collaterals and does not involve an interneurone. A reflected discharge in the lateral olfactory tract is demonstrated and this can account for periodical following in antidromic driving of mitral cells at high frequencies. Antidromic stimulation of the lateral olfactory tract also causes or permits firing of cells in the external plexiform layer which appears not to be, inhibitory interneurons.