Transformation of Olfactory Representations in the <i>Drosophila</i> Antennal Lobe

TLDR

Molecular genetics shows a precise stereotypy in how primary olfactory sensory neurons project to secondary neurons. The study aims to understand how this mapping translates into odor responses in second‑order neurons. The authors used in vivo whole‑cell recordings in Drosophila to investigate this question. Monomolecular odors evoke responses in large ensembles of antennal‑lobe neurons, and second‑order neurons show broader tuning and more complex responses than primary afferents, indicating a major transformation of odor representations mediated by lateral interactions.

Abstract

Molecular genetics has revealed a precise stereotypy in the projection of primary olfactory sensory neurons onto secondary neurons. A major challenge is to understand how this mapping translates into odor responses in these second-order neurons. We investigated this question in Drosophila using whole-cell recordings in vivo. We observe that monomolecular odors generally elicit responses in large ensembles of antennal lobe neurons. Comparison of odor-evoked activity from afferents and postsynaptic neurons in the same glomerulus revealed that second-order neurons display broader tuning and more complex responses than their primary afferents. This indicates a major transformation of odor representations, implicating lateral interactions within the antennal lobe.