eLife assessment
The work shows that the experimental application of serotonin to locust antennal lobes induces an increased feeding-related response to some odorants (even in food-satiated animals). To explain how the odorant-specific effects are seen despite similar consequences of 5-HT modulation on all projection neuronal types analyses by electrophysiology, the authors propose a simple quantitative model built around PNs with different downstream connections. These convincing observations are useful to guide further studies of serotonin and other modulatory mechanisms in the olfactory system.