Mapping of odor-related neuronal activity in the olfactory bulb by high-resolution 2-deoxyglucose autoradiography.

Abstract

The spatial distribution of odor-induced neuronal activity in the olfactory bulb, the 1st relay station of the olfactory pathway, is believed to reflect important aspects of chemosensory coding. The application of high-resolution 2-deoxyglucose autoradiography to the mapping of spatial patterns of metabolic activity at the level of single neurons in the olfactory bulb of rats and tiger salamanders (Ambystoma tigrinum) is reported. Glomeruli, which are synaptic complexes containing the 1st synaptic relay, tend to be uniformly active or inactive during odor exposure. Differential 2-deoxyglucose uptake was observed in the somata of projection neurons (mitral cells) and interneurons (periglomerular and granule cells). The glomerulus apparently serves as a functional unit of activity. The high-resolution results are interpreted in terms of the well-characterized synaptic organization of the olfactory bulb and serve to illustrate the capability of the 2-deoxyglucose autoradiographic technique to map metabolic activity in single neurons of the vertebrate CNS.