In the natural environment, odors are often blends of many compounds at different concentrations. A question arises then, how does the olfactory system encode different mixtures of odors? The vinegar fly represents hereby a premier model system to study olfactory processing and mixture coding since the olfactory circuitry exhibits a stereotyped architecture which is similar to its mammalian counterpart, but which is less complex and highly tractable as well as susceptible to genetic manipulations. In a previous paper, we demonstrated that mixtures of odors having opposing hedonic valances valences (at certain ratios) are encoded and processed by a mixture-specific activation of projection neurons, the output neurons of the fly antennal lobe (Mohamed et al., 2019). This mixture code is maintained through lateral inhibition in an anisotropic manner initiated between glomeruli encoding opposing odor valences. We found that the activity of patchy and sparse local interneurons mediate this specific form of mixture inhibition. The goal of this project is to study the calcium dynamics of these patchy local interneurons in response to diverse odor mixtures, at the level of their pre- and post-synaptic activitiessites. We will investigate both the population dynamics, as well as activities at the single neuron level using two-photon functional imaging of the fly antennal lobe using SPARC.
This work is supported by the DFG as a part of SPP 2205: Evolutionary Optimisation of Neuronal Processing project