André Fiala, Annette Witt, and Marc Timme

Odour processing by neuronal circuits is complex, highly multidimensional, and transient. Odours activate or inhibit a diverse array of olfactory receptor neurons, thereby inducing dynamical processes in downstream circuits. In Drosophila, such sensory signals affect a neuronal network within the antennal lobe where odours are represented by dynamically interacting neurons of three different types: sensory neurons (SNs), excitatory and inhibitory local interneurons (eLIs, iLIs), and projection neurons (PNs). So far, it is unclear how SNs, LIs, and PNs cooperatively interact to support odor distinction and odour classification. Drosophila provides an ideal model system for studying spatiotemporal olfactory processing, because subpopulations of neurons can be genetically targeted. This project aims at describing, quantifying and modelling how the various parts of the primary olfactory circuitry contribute to spatio-temporal odour representation and how their dynamics directly relate to computations and resulting behaviours. In particular, we are going to investigate the following problems:

(A) Finding a quantitative description of odour representation in the antennal lobe,

(B) Modifying odor representations by imprinting the animals (i.e., a continuous exposure of Drosophila to odorants and odor combinations during a critical time window),

(C) Modelling the mode of action of olfactory neurons, in particular in LIs, in terms of recurrent neural circuit models.

In summary, this study will help to dissect the contributions of various neuronal subpopulations for odour coding and thus provide important functional information for both odour coding and olfactory imprinting in flies.