Integration mechanisms of parallel olfactory processing pathways

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K06732
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 44050:Animal physiological chemistry, physiology and behavioral biology-related
• 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): 2020-04-01 – 2023-03-31
• Keywords: 昆虫 / キノコ体 / 細胞内記録 / 統合処理 / ケニオン細胞 / 嗅覚情報処理 / 前大脳側葉 / 層構造

Outline of Final Research Achievements

Parallel olfactory pathways are prevalent in both vertebrates and invertebrates. Our previous studies have shown that two parallel pathways that stem from distinct types of sensilla in the antenna are delivered to gamma and non-gamma regions of the mushroom body via distinct populations of of projection neurons in the American cockroach. In order to elucidate how these pathways are integrated in the mushroom body, we applied intracellular recordings and stainings to extrinsic neurons of the mushroom body in the male cockroach. The extrinsic neurons were classified into input and output neurons. Whereas input neurons had axon terminals extensively in both gamma and non-gamma regions, output neurons had dendrites in either or both regions. Each type of output neurons had distinct physiological properties. These results suggested that two parallel pathways are generally segregated but partly integrated at the level of the mushroom body output.

Free Research Field

神経行動学

Academic Significance and Societal Importance of the Research Achievements

嗅覚並行経路は同じ匂いに付随する異なる性質を処理すると推定される経路で、無脊椎動物、脊椎動物に広く見られるが、並行経路がどこでどう統合されるのかは理解されていない。本研究は嗅覚依存度の高い夜行性の動物（ゴキブリ）を用い、その2本の並行経路の統合様式を高次中枢（キノコ体）の外来性ニューロンの細胞内記録/染色により探る独自性の高い研究であり、得られた結果は並行経路の機能的意義や進化のみならず、嗅覚中枢の発達、匂いの情報統合、記憶の形成機構、行動決定など神経科学の諸課題に深い示唆を与えるものである。