Configural or elemental representation of complex odor stimuli in the olfactory system of Drosophila melanogaster

DUARTE LAUTARO; LOCATELLI FERNANDO; NICOLAS PIREZ

Cordoba

Congreso; XXXIV Reunión Anual SAN 2019; 2019

The olfactory system is an excellent model tostudy how sensory stimuli are detected and processed in the brain. Odormolecules bind to receptor proteins expressed in the olfactory receptor neurons(ORNs), which project to the antennal lobe (AL). Here, all ORNs that expressthe same receptor converge into glomeruli and make contact with projectionneurons (PNs), which constitute the output of the AL, and with local neurons(LNs) that form a network of lateral interactions. Due to the spatialorganization of the input to the AL, each odor is encoded as a combination ofcoactivated glomeruli. The response elicited by a mixture of odors differs fromthe summation of the activity elicited by the elements that constitute themixture. It is thought that this non-elemental representation accounts for the perceptionof the mixture as a novel stimulus, different from the components. Here we studythe representation of pure odors and its mixture in the AL of Drosophila melanogaster flies. Weperform optical calcium imaging at the level of the AL by expressing GCaMP6 inthe PNs. We measure the representation of pure odors and mixtures. Thedifferences among the patterns of activity elicited by the mixture and thoseexpected on the basis of the activity elicited by pure components reveals theaction of the local network which is based mainly on GABAergic inhibitions.Future studies are directed to measure the representation of the mixture whileinterfering with the action of the LNs.