Abstract
In Drosophila antennal lobe, olfactory receptor neurons (ORNs) of the same receptor type project to the same glomerulus and make synaptic connections with projection neurons (PNs), which project to higher brain center. The ORNs-glomerulus-PNs pathway forms a channel-like structure, which is heavily innervated by local interneurons (LNs). LNs likely play roles in modulating response of PNs to ORN inputs and in exchanging the olfactory information between channels. Using the wiring diagram of LNs, our analysis showed that the innervation number and the innervation specificity of individual LNs are very diverse while they form a specific innervation pattern that correlates with ORN responses to a certain class of odors. Our result suggests that the neural network architecture of the antennal lobe is extremely complex and beyond the explanation of existing theories. Therefore, we need to reexamine the current theories and, possibly, develop a new theory for the functions of LNs in antennal lobe.