Functional significance of two parallel olfactory pathways

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K07479
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Animal physiology/Animal behavior
• Research Institution: Hokkaido University
• Principal Investigator: NISHINO HIROSHI 北海道大学, 電子科学研究所, 助教 (80332477)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 昆虫 / 嗅覚 / 並行経路 / 投射ニューロン / 触角葉 / キノコ体 / ケニオン細胞 / 記憶中枢

Outline of Final Research Achievements

Parallel olfactory pathways were seen in brains of both vertebrates and invertebrates, but the functional aspects of segregated olfactory pathways is still unclear. To address this problem, we have used the cockroach Periplaneta americana which heavily relies on olfaction for resource searching. Our aim of this study was to characterize 1) whether two parallel pathways are maintained in Kenyon cells that constitute the mushroom body, 2) which information is encoded by the two parallel pathways. Dye injections into the axons of small populations of Kenyon cells revealed that two pathways are maintained by distinct subgroups of Kenyon cells, class I and class II cells. Intracellular recordings from output neurons of the first-order olfactory center (antennal lobe) revealed that activity of these neurons is modified by air flow that deliver odor molecules and that the modification manners differed between output neurons belonging to two distinct pathways.

Free Research Field

神経行動学

Academic Significance and Societal Importance of the Research Achievements

本発見は2本の嗅覚並行経路を形成する単一糸球体投射ニューロンが嗅質の違いのみならず、匂いを運ぶ媒体（＝気流）によっても修飾されることを示した。また、嗅覚並行経路がキノコ体までは維持されるが、これ以降の階層では並行処理された情報の統合がおこることを明確に示した。以上の成果は進化的に古い昆虫においても周囲の環境の違いに応じたダイナミックな匂い情報処理がなされること、キノコ体（記憶中枢）においても匂いの並列処理が維持されることを示した研究であり、動物の匂い情報処理の動的性質について多大な示唆を与えるものである。