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When the electrophysiological response of the olfactory bulb to lateral olfactory tract stimulation is compared with its response to olfactory nerve stimulation, two major differences appear in the field potentials thus obtained. These have been investigated and ascribed to the activity of the glomerular layer by Freeman. In this study we explored the electrophysiological maturation of the glomerular layer in normal and anosmic bulbs of- postnatal rats using these two characteristics, named the <> and the <>. The results revealed that both the transmission attenuation (which appear to be related to the glomerular structure as a whole and its glial enca psulation) and the base line shift began to show mature characteristics after day 12 and were completely matured by day 15. This is in accord with anatomical findings which show histological maturation of glomerular structure and synapses preceed the electrophysiological maturity by a few days.
In anosmic bulbs the responses with regard to the characteristics under consideration, are more or less like normal animals.