Institute of Neurophysiology and Cellular Biophysics

Mapping of odors in the olfactory bulb

ORNs project into different zones of the OB. Glomeruli activated by amino acids are located laterally compared to those activated by cAMP pathway activators. This unequal projection to the OB is consistent with our finding that the glomerular layer in larval Xenopus laevis is organized in spatially distinct clusters, and that the presynaptic proteins synaptophysin and synaptotagmin are differentially expressed in glomeruli in the lateral and medial OB. Taken together, the glomerular layer of the OB of larval Xenopus laevis is organized in spatially distinct clusters that receive input from different subsets of ORNs with varying transduction mechanisms, odorant spectra and an unequal composition of presynaptic proteins. This strongly suggests that the main olfactory system of larval Xenopus laevis is made up of at least two diverse subsystems with different functional relevance possibly emerged at different points in the evolution of the olfactory system.