Comprehensive mapping of odor-evoked activity underlying presynaptic plasticity in compartmentalized axonal lobes of Drosophila mushroom body

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K17681
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Animal physiology/Animal behavior; Nerve anatomy/Neuropathology
• Research Institution: The University of Tokyo
• Principal Investigator: Abe Takashi 東京大学, 定量生命科学研究所, 助教 (70756824)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 2光子顕微鏡カルシウムイメージング / 嗅覚記憶学習 / ショウジョウバエ / キノコ体

Outline of Final Research Achievements

In Drosophila, the mushroom body (MB) has been studied for its essential role in olfactory associative memory. It has been known that Kenyon cells (KCs), the 3rd-ordered intrinsic neurons, are anatomically subdivided into distinct 7 subtypes and each type seems to play different functional role during the memory. Their output sites, called γ(m and d), α'/β'(ap and s), and α/β(p, s, and c) lobes, are compartmentalized into 15 sub-regions by their synaptic partners, MBONs and DANs. Moreover, post-synaptic plasticity has been shown in several types of MBONs by 2-photon calcium imaging with single cell level resolution.
However, it is not clear whether such plasticity is also detectable in the pre-synaptic sites of MB, the axonal lobes of KCs. To address this question, we first aimed to describe dynamics of the innate odor responses of the 7 KC subtypes using cell type specific split-gal4 drivers, combining with the lexA-based compartment labeling in their output regions.

Free Research Field

神経生物学

Academic Significance and Societal Importance of the Research Achievements

キノコ体のポストシナプス側であるMBON神経においては、網羅的に単一神経レベルの解像度で匂い応答が調べられ、可塑的変化が顕微鏡下で示された。
一方、プレシナプス側であるKCsにも可視的に検出可能なレベルの可塑性があるのかどうかは未だはっきりしていない。これには、それぞれのKCサブタイプの区画化された出力域においてどのような活動や制御があるのかについて多くが未知であり、変化の検出の前提となる生理学的知見が不足していることが一因として考えられる。サブタイプを分離した発現系統を用いることで、可視的に、時空間的分解能が高い回路地図の構築が可能となり、匂い記憶の形成メカニズムの理解に近づけると考える。