Concentric zones for pheromone components in the mushroom body calyx of the moth brain

Authors

  • Shigehiro Namiki,

    1. Intelligent Cooperative Systems Laboratory, Research Center for Advanced Science and Technology, University of Tokyo, Tokyo 153-8904, Japan
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  • Mitsuko Takaguchi,

    1. Intelligent Cooperative Systems Laboratory, Research Center for Advanced Science and Technology, University of Tokyo, Tokyo 153-8904, Japan
    2. Graduate School of Life and Environmental Sciences, University of Tsukuba, Ibaraki 305-8572, Japan
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  • Yoichi Seki,

    1. Intelligent Cooperative Systems Laboratory, Research Center for Advanced Science and Technology, University of Tokyo, Tokyo 153-8904, Japan
    2. Graduate School of Life and Environmental Sciences, University of Tsukuba, Ibaraki 305-8572, Japan
    3. Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Jena DE D-07745, Germany
    Current affiliation:
    1. Laboratory of Cellular Neurobiology, School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan
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  • Tomoki Kazawa,

    1. Intelligent Cooperative Systems Laboratory, Research Center for Advanced Science and Technology, University of Tokyo, Tokyo 153-8904, Japan
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  • Ryota Fukushima,

    1. Intelligent Cooperative Systems Laboratory, Research Center for Advanced Science and Technology, University of Tokyo, Tokyo 153-8904, Japan
    2. Graduate School of Life and Environmental Sciences, University of Tsukuba, Ibaraki 305-8572, Japan
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  • Chika Iwatsuki,

    1. Intelligent Cooperative Systems Laboratory, Research Center for Advanced Science and Technology, University of Tokyo, Tokyo 153-8904, Japan
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  • Ryohei Kanzaki

    Corresponding author
    1. Intelligent Cooperative Systems Laboratory, Research Center for Advanced Science and Technology, University of Tokyo, Tokyo 153-8904, Japan
    2. Graduate School of Information Science and Technology, University of Tokyo, Tokyo 113-8656, Japan
    • Research Center for Advanced Science and Technology, University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo 153-8904, Japan
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Abstract

The spatial distribution of input and output neurons in the mushroom body (MB) calyx was investigated in the silkmoth Bombyx mori. In Lepidoptera, the brain has a specialized system for processing sex pheromones. How individual pheromone components are represented in the MB has not yet been elucidated. Toward this end, we first compared the distribution of the presynaptic boutons of antennal lobe projection neurons (PNs), which transfer odor information from the antennal lobe to the MB calyx. The axons of PNs that innervate pheromonal glomeruli were confined to a relatively small area within the calyx. In contrast, the axons of PNs that innervate nonpheromonal glomeruli were more widely distributed. PN axons for the minor pheromone component covered a larger area than those for the major pheromone component and partially overlapped with those innervating nonpheromonal glomeruli, suggesting the integration of the minor pheromone component with plant odors. Overall, we found that PN axons innervating pheromonal and nonpheromonal glomeruli were organized into concentric zones. We then analyzed the dendritic fields of Kenyon cells (KCs), which receive inputs from PNs. Despite the strong regional localization of axons of different PN classes, the dendrites of KCs were less well classified. Finally, we estimated the connectivity between PNs and KCs and suggest that the dendritic field may be organized to receive different amounts of pheromonal and nonpheromonal inputs. PNs for multiple pheromone components and plant odors enter the calyx in a concentric fashion, and they are read out by the elaborate dendritic field of KCs. J. Comp. Neurol. 521:1073–1092, 2013. © 2012 Wiley Periodicals, Inc.

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