Spatial Representation of Odorant Valence in an Insect Brain

• Published in: Cell reports (Cambridge) 2012-04, Vol.1 (4), p.392-399
• Main Authors: Knaden, Markus, Strutz, Antonia, Ahsan, Jawaid, Sachse, Silke, Hansson, Bill S.
• Format: Article
• Language: English
• Subjects: Animals; Arthropod Antennae - physiology; Brain - physiology; Brain Mapping; Cues; Drosophila melanogaster; Drosophila melanogaster - physiology; Mice; Odorants; Olfactory Bulb - physiology; Olfactory Receptor Neurons - drug effects; Olfactory Receptor Neurons - physiology; Stimulation, Chemical
• ISSN: 2211-1247; 2211-1247
• DOI: 10.1016/j.celrep.2012.03.002

Brains have to decide whether and how to respond to detected stimuli based on complex sensory input. The vinegar fly Drosophila melanogaster evaluates food sources based on olfactory cues. Here, we performed a behavioral screen using the vinegar fly and established the innate valence of 110 odorants. Our analysis of neuronal activation patterns evoked by attractive and aversive odorants suggests that even though the identity of odorants is coded by the set of activated receptors, the main representation of odorant valence is formed at the output level of the antennal lobe. The topographic clustering within the antennal lobe of valence-specific output neurons resembles a corresponding domain in the olfactory bulb of mice. The basal anatomical structure of the olfactory circuit between insects and vertebrates is known to be similar; our study suggests that the representation of odorant valence is as well. [Display omitted] ► We establish the innate hedonic valence of 110 odors for Drosophila melanogaster ► A clear valence of odors is first represented at the output of the antennal lobe ► Aversive- and attractive-specific glomeruli cluster in separate functional areas Drosophila melanogaster strongly depends on olfaction to assess food, oviposition sites, and mates. Knaden, Hansson, and colleagues screened 110 odorants for olfactory valence and compared neuronal activation patterns evoked by the most aversive and most attractive compounds. A correlation of neuronal activity and valence was found within the projection neurons (PNs) of the antennal lobe (AL). Aversive specific PNs clustered in the lateral part of the AL, whereas PNs specific for attractive odorants clustered in the medial part.