Local interneurons are essential in information processing by neural circuits. Here we present a comprehensive genetic, anatomical and electrophysiological analysis of local interneurons (LNs) in the Drosophila melanogaster antennal lobe, the first olfactory processing center in the brain. We found LNs to be diverse in their neurotransmitter profiles, connectivity and physiological properties. Analysis of >1,500 individual LNs revealed principal morphological classes characterized by coarsely stereotyped glomerular innervation patterns. Some of these morphological classes showed distinct physiological properties. However, the finer-scale connectivity of an individual LN varied considerably across brains, and there was notable physiological variability within each morphological or genetic class. Finally, LN innervation required interaction with olfactory receptor neurons during development, and some individual variability also likely reflected LN–LN interactions. Our results reveal an unexpected degree of complexity and individual variation in an invertebrate neural circuit, a result that creates challenges for solving the Drosophila connectome.
Subscribe to Journal
Get full journal access for 1 year
only $4.92 per issue
All prices are NET prices.
VAT will be added later in the checkout.
Tax calculation will be finalised during checkout.
Rent or Buy article
Get time limited or full article access on ReadCube.
All prices are NET prices.
Markram, H. et al. Interneurons of the neocortical inhibitory system. Nat. Rev. Neurosci. 5, 793–807 (2004).
Olsen, S.R. & Wilson, R.I. Cracking neural circuits in a tiny brain: new approaches for understanding the neural circuitry of Drosophila. Trends Neurosci. 31, 512–520 (2008).
Vosshall, L.B. & Stocker, R.F. Molecular architecture of smell and taste in Drosophila. Annu. Rev. Neurosci. 30, 505–533 (2007).
Shepherd, G.M., Chen, W.R. & Greer, C.A. Olfactory Bulb. in The synaptic Organization of the Brain (ed. Shepherd, G.M.) (Oxford University Press, Oxford, 2004).
Lledo, P.M., Merkle, F.T. & Alvarez-Buylla, A. Origin and function of olfactory bulb interneuron diversity. Trends Neurosci. 31, 392–400 (2008).
Wachowiak, M. & Shipley, M.T. Coding and synaptic processing of sensory information in the glomerular layer of the olfactory bulb. Semin. Cell Dev. Biol. 17, 411–423 (2006).
Christensen, T.A., Waldrop, B.R., Harrow, I.D. & Hildebrand, J.G. Local interneurons and information processing in the olfactory glomeruli of the moth Manduca sexta. J. Comp. Physiol. A 173, 385–399 (1993).
Seki, Y. & Kanzaki, R. Comprehensive morphological identification and GABA immunocytochemistry of antennal lobe local interneurons in Bombyx mori. J. Comp. Neurol. 506, 93–107 (2008).
MacLeod, K. & Laurent, G. Distinct mechanisms for synchronization and temporal patterning of odor-encoding neural assemblies. Science 274, 976–979 (1996).
Fonta, C., Sun, X.J. & Masson, C. Morphology and spatial distribution of bee antennal lobe interneurons responsive to odours. Chem. Senses 18, 101–119 (1993).
Ernst, K.D. & Boeckh, J. A neuroanatomical study on the organization of the central antennal pathways in insects. III. Neuroanatomical characterization of physiologically defined response types of deutocerebral neurons in Periplaneta americana. Cell Tissue Res. 229, 1–22 (1983).
Stocker, R.F., Lienhard, M.C., Borst, A. & Fischbach, K.F. Neuronal architecture of the antennal lobe in Drosophila melanogaster. Cell Tissue Res. 262, 9–34 (1990).
Wilson, R.I. & Laurent, G. Role of GABAergic inhibition in shaping odor-evoked spatiotemporal patterns in the Drosophila antennal lobe. J. Neurosci. 25, 9069–9079 (2005).
Shang, Y., Claridge-Chang, A., Sjulson, L., Pypaert, M. & Miesenbock, G. Excitatory local circuits and their implications for olfactory processing in the fly antennal lobe. Cell 128, 601–612 (2007).
Ng, M. et al. Transmission of olfactory information between three populations of neurons in the antennal lobe of the fly. Neuron 36, 463–474 (2002).
Lai, S.L., Awasaki, T., Ito, K. & Lee, T. Clonal analysis of Drosophila antennal lobe neurons: diverse neuronal architectures in the lateral neuroblast lineage. Development 135, 2883–2893 (2008).
Das, A. et al. Drosophila olfactory local interneurons and projection neurons derive from a common neuroblast lineage specified by the empty spiracles gene. Neural Dev. 3, 33 (2008).
Okada, R., Awasaki, T. & Ito, K. Gamma-aminobutyric acid (GABA)-mediated neural connections in the Drosophila antennal lobe. J. Comp. Neurol. 514, 74–91 (2009).
Lee, T. & Luo, L. Mosaic analysis with a repressible cell marker for studies of gene function in neuronal morphogenesis. Neuron 22, 451–461 (1999).
Olsen, S.R., Bhandawat, V. & Wilson, R.I. Excitatory interactions between olfactory processing channels in the Drosophila antennal lobe. Neuron 54, 89–103 (2007).
Lee, T., Lee, A. & Luo, L. Development of the Drosophila mushroom bodies: sequential generation of three distinct types of neurons from a neuroblast. Development 126, 4065–4076 (1999).
Jefferis, G.S.X.E., Marin, E.C., Stocker, R.F. & Luo, L. Target neuron prespecification in the olfactory map of Drosophila. Nature 414, 204–208 (2001).
Jefferis, G.S. et al. Comprehensive maps of Drosophila higher olfactory centers: spatially segregated fruit and pheromone representation. Cell 128, 1187–1203 (2007).
van der Goes van Naters, W. & Carlson, J.R. Receptors and neurons for fly odors in Drosophila. Curr. Biol. 17, 606–612 (2007).
Hallem, E.A. & Carlson, J.R. Coding of odors by a receptor repertoire. Cell 125, 143–160 (2006).
Sachse, S. et al. Activity-dependent plasticity in an olfactory circuit. Neuron 56, 838–850 (2007).
Wassle, H., Peichl, L. & Boycott, B.B. Dendritic territories of cat retinal ganglion cells. Nature 292, 344–345 (1981).
Grueber, W.B., Jan, L.Y. & Jan, Y.N. Tiling of the Drosophila epidermis by multidendritic sensory neurons. Development 129, 2867–2878 (2002).
Jefferis, G.S. et al. Developmental origin of wiring specificity in the olfactory system of Drosophila. Development 131, 117–130 (2004).
Sweeney, L.B. et al. Temporal target restriction of olfactory receptor neurons by Semaphorin-1a/PlexinA-mediated axon-axon interactions. Neuron 53, 185–200 (2007).
Berdnik, D., Chihara, T., Couto, A. & Luo, L. Wiring stability of the adult Drosophila olfactory circuit after lesion. J. Neurosci. 26, 3367–3376 (2006).
Luo, L. & Flanagan, J.G. Development of continuous and discrete neural maps. Neuron 56, 284–300 (2007).
Pirez, N. & Wachowiak, M. In vivo modulation of sensory input to the olfactory bulb by tonic and activity-dependent presynaptic inhibition of receptor neurons. J. Neurosci. 28, 6360–6371 (2008).
Shao, Z., Puche, A.C., Kiyokage, E., Szabo, G. & Shipley, M.T. Two GABAergic intraglomerular circuits differentially regulate tonic and phasic presynaptic inhibition of olfactory nerve terminals. J. Neurophysiol. 101, 1988–2001 (2009).
Bhandawat, V., Olsen, S.R., Gouwens, N.W., Schlief, M.L. & Wilson, R.I. Sensory processing in the Drosophila antennal lobe increases reliability and separability of ensemble odor representations. Nat. Neurosci. 10, 1474–1482 (2007).
Schlief, M.L. & Wilson, R.I. Olfactory processing and behavior downstream from highly selective receptor neurons. Nat. Neurosci. 10, 623–630 (2007).
Miles, R. Perspectives: neurobiology. Diversity in inhibition. Science 287, 244–246 (2000).
Lu, J., Tapia, J.C., White, O.L. & Lichtman, J.W. The interscutularis muscle connectome. PLoS Biol. 7, e32 (2009).
Marin, E.C., Jefferis, G.S.X.E., Komiyama, T., Zhu, H. & Luo, L. Representation of the glomerular olfactory map in the Drosophila brain. Cell 109, 243–255 (2002).
Wong, A.M., Wang, J.W. & Axel, R. Spatial representation of the glomerular map in the Drosophila protocerebrum. Cell 109, 229–241 (2002).
Murthy, M., Fiete, I. & Laurent, G. Testing odor response stereotypy in the Drosophila mushroom body. Neuron 59, 1009–1023 (2008).
Lichtman, J.W. & Sanes, J.R. Ome sweet ome: what can the genome tell us about the connectome? Curr. Opin. Neurobiol. 18, 346–353 (2008).
Laissue, P.P. et al. Three-dimensional reconstruction of the antennal lobe in Drosophila melanogaster. J. Comp. Neurol. 405, 543–552 (1999).
Hayashi, S. et al. GETDB, a database compiling expression patterns and molecular locations of a collection of Gal4 enhancer traps. Genesis 34, 58–61 (2002).
Martin, J.R., Ernst, R. & Heisenberg, M. Mushroom bodies suppress locomotor activity in Drosophila melanogaster. Learn. Mem. 5, 179–191 (1998).
Stocker, R.F., Heimbeck, G., Gendre, N. & de Belle, J.S. Neuroblast ablation in Drosophila P[GAL4] lines reveals origins of olfactory interneurons. J. Neurobiol. 32, 443–456 (1997).
Kim, J. et al. A TRPV family ion channel required for hearing in Drosophila. Nature 424, 81–84 (2003).
Dubnau, J. et al. The staufen/pumilio pathway is involved in Drosophila long-term memory. Curr. Biol. 13, 286–296 (2003).
Gouwens, N.W. & Wilson, R.I. Signal propagation in Drosophila central neurons. J. Neurosci. 29, 6239–6249 (2009).
Hallem, E.A., Ho, M.G. & Carlson, J.R. The molecular basis of odor coding in the Drosophila antenna. Cell 117, 965–979 (2004).
We thank U. Heberlein (University of California, San Francisco) and E. Marin for respectively providing and screening unpublished Gal4 lines, which lead to identification of line 1 and line 6; J. Simpson (Janelia Farm, Howard Hughes Medical Institute) for providing unpublished LCCH3 (line 7) Gal4; K. Wehner (Stanford University) for mouse anti-HA; A. DiAntonio (Washington University) for rabbit anti-DVGLUT; and the Bloomington Stock Center, Kyoto Stock Center, Drosophila Genetic Resource Center, Gal4 Enhancer Trap Insertion Database (GETDB), and Developmental Studies Hybridoma Bank for other reagents. M.L.S. is grateful for the help of J. Brooks in data collection. We thank the Stanford Department of Statistics Consulting Service for technical help with statistical analyses. We thank T. Clandinin, G. Jefferis and members of the Luo and Wilson laboratories for helpful comments on the manuscript. This work was supported by US National Institutes of Health grants to L.L. (R01-DC005982) and R.I.W. (R01-DC008174), a Pew Scholar award, a McKnight Scholar award, a Sloan Foundation research fellowship, and a Beckman Young Investigator award (to R.I.W). M.L.S. is supported by a US National Research Service predoctoral award. E.Y. is supported by a Human Frontiers Science Program Long Term Fellowship. J.C.S.L. is supported by the Medical Scientist Training Program at Stanford University. L.L. receives investigator support from the Howard Hughes Medical Institute.
The authors declare no competing financial interests.
Supplementary Tables 1 and 4, Supplementary Figures 1–11 (PDF 1737 kb)
Raw data for ipsilateral glomerular innervation patterns (XLS 639 kb)
Raw data for contralateral glomerular innervation patterns of bilateral projection LNs (XLS 52 kb)
About this article
Cite this article
Chou, YH., Spletter, M., Yaksi, E. et al. Diversity and wiring variability of olfactory local interneurons in the Drosophila antennal lobe. Nat Neurosci 13, 439–449 (2010). https://doi.org/10.1038/nn.2489
Cell and Tissue Research (2021)
Cell and Tissue Research (2021)
Targeted molecular profiling of rare olfactory sensory neurons identifies fate, wiring, and functional determinants
Cell and Tissue Research (2021)
A Population of Interneurons Signals Changes in the Basal Concentration of Serotonin and Mediates Gain Control in the Drosophila Antennal Lobe
Current Biology (2020)