Decoding of Context-Dependent Olfactory Behavior in Drosophila

• Published in: Neuron (Cambridge, Mass.) Vol. 91; no. 1; pp. 155 - 167
• Main Authors: Badel, Laurent, Ohta, Kazumi, Tsuchimoto, Yoshiko, Kazama, Hokto
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 06.07.2016; Elsevier Limited
• Subjects: Animals; Behavior; Behavior, Animal - physiology; Brain - metabolism; Brain research; Data analysis; Drosophila melanogaster; Drosophila Proteins - metabolism; Experiments; Insects; Odors; Olfactory Pathways - metabolism; Olfactory Receptor Neurons - metabolism; Smell - physiology; Studies
• ISSN: 0896-6273; 1097-4199
• DOI: 10.1016/j.neuron.2016.05.022

Odor information is encoded in the activity of a population of glomeruli in the primary olfactory center. However, how this information is decoded in the brain remains elusive. Here, we address this question in Drosophila by combining neuronal imaging and tracking of innate behavioral responses. We find that the behavior is accurately predicted by a model summing normalized glomerular responses, in which each glomerulus contributes a specific, small amount to odor preference. This model is further supported by targeted manipulations of glomerular input, which biased the behavior. Additionally, we observe that relative odor preference changes and can even switch depending on the context, an effect correctly predicted by our normalization model. Our results indicate that olfactory information is decoded from the pooled activity of a glomerular repertoire and demonstrate the ability of the olfactory system to adapt to the statistics of its environment. •Olfactory behavior is predicted by superposition of normalized glomerular activity•Behavioral/neuronal responses to binary mixtures scale linearly with mixing ratio•Manipulation of glomerular activity biases behavior according to the decoding model•Relative valence of odors changes and even switches depending on the context Badel et al. show that flies’ innate odor responses can be predicted by a weighted sum of normalized glomerular activity. They further demonstrate that relative odor preference switches depending on the olfactory context as predicted by their decoding model.