Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.neuron.2017.11.008

Language：English   Publishing type：Research paper (scientific journal)  

During early development, neurons in the brain often form excess synaptic connections. Later, they strengthen some connections while eliminating others to build functional neuronal circuits. In the olfactory bulb, a mitral cell initially extends multiple dendrites to multiple glomeruli but eventually forms a single primary dendrite through the activity-dependent dendrite pruning process. Recent studies have reported that microglia facilitate synapse pruning during the circuit remodeling in some systems. It has remained unclear whether microglia are involved in the activity-dependent dendrite pruning in the developing brains. Here, we examined whether microglia are required for the developmental dendrite pruning of mitral cells in mice. To deplete microglia in the fetal brain, we treated mice with a CSF1R inhibitor, PLX5622, from pregnancy. Microglia were reduced by >90% in mice treated with PLX5622. However, dendrite pruning of mitral cells was not significantly affected. Moreover, we found no significant differences in the number, density, and size of excitatory synapses formed in mitral cell dendrites. We also found no evidence for the role of microglia in the activity-dependent dendrite remodeling of layer 4 neurons in the barrel cortex. In contrast, the density of excitatory synapses (dendritic spines) in granule cells in the olfactory bulb was significantly increased in mice treated with PLX5622 at P6, suggesting a role for the regulation of dendritic spines. Our results indicate that microglia do not play a critical role in activity-dependent dendrite pruning at the neurite level during early postnatal development in mice.Significance StatementSynapse elimination is essential for activity-dependent circuit remodeling in the developing brains of mammals. Recent studies suggested that microglia play a critical role in the synapse elimination. This study found that microglia are dispensable for the activity-dependent dendrite pruning in developing mitral cells and layer 4 neurons in the barrel cortex. Thus, microglia are not critical for activity-dependent dendrite pruning at the neurite level during normal developmental process.

DOI： 10.1523/ENEURO.0323-23.2023

Web of Science

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PubMed

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Publisher：医歯薬出版  

DOI： 10.32118/ayu28605365

CiNii Research

Authorship：Corresponding author   Language：Japanese   Publisher：Japan Association on Odor Environment  

<p>In the olfactory system, individual odorants are recognized by a combination of approximately 400 types of odorant receptors. However, it remains poorly understood how mixtures of multiple odorants are recognized. Recent advances in high-throughput imaging techniques have revealed how mixtures of odorants are recognized by olfactory sensory neurons <i>in vivo</i>. In this review, I describe antagonism and synergy, which happens at the level of odorant receptors, and discuss mechanisms of odor mixture discrimination. I also discuss implications from the recently reported structural analysis of an odorant receptor.</p>

DOI： 10.2171/jao.54.139

CiNii Research

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Language：Japanese   Publisher：The Japanese Association for the Study of Taste and Smell  

DOI： 10.18965/tasteandsmell.30.2_101

CiNii Research

Language：Japanese   Publisher：(公財)上原記念生命科学財団  

Language：Others  

DOI： 10.1101/2022.10.20.512984

Language：Others  

Development of the olfactory system: from sensory neurons to cortical projections

Other Link： https://www.taylorfrancis.com/chapters/edit/10.1201/9781003092810-2/development-olfactory-system-takeshi-imai

Repository Public URL： https://hdl.handle.net/2324/6787716

Language：Others   Publishing type：Research paper (scientific journal)  

DOI： 10.3389/fnana.2021.760063

Language：Others   Publishing type：Research paper (scientific journal)  

In vivo Optical Access to Olfactory Sensory Neurons in the Mouse Olfactory Epithelium

DOI： 10.21769/bioprotoc.4055

Language：English  

Optical Clearing and Index Matching of Tissue Samples for High-resolution Fluorescence Imaging Using SeeDB2

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1186/s13059-017-1154-x

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1523/ENEURO.0242-16.2016

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.celrep.2016.02.057

Language：English  

DOI： 10.1016/j.semcdb.2014.07.012

Language：English  

Optical Clearing Using SeeDB.

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.cell.2013.08.033

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1038/nn.3447

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1038/srep01716

Language：Others  

Quartz-Seq: a highly reproducible and sensitive single-cell RNA sequencing method, reveals non-genetic gene-expression heterogeneity.

DOI： 10.1186/gb-2013-14-4-r31

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1186/gb-2013-14-4-r31

Language：English  

DOI： 10.1111/j.1440-169X.2012.01334.x

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1111/j.1460-9568.2011.07817.x

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1111/j.1460-9568.2010.07495.x

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1101/cshperspect.a001776

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1126/science.1173596

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.conb.2008.07.009

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.conb.2007.08.002

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1126/science.1131794

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1111/j.1460-9568.2006.04675.x

Language：Japanese   Publisher：(一社)日本解剖学会  

近年,様々な組織透明化法が開発されたことで,生体組織を3次元的に蛍光観察することが可能となった.蛍光イメージングの1つの利点は,異なる波長の光を用いて多色解析ができる点にある.しかしながら,透明化標本を用いて多色イメージングを行う際には,いくつか注意すべき点もある.本稿では,透明化標本を用いて定量的に多色イメージングを行う上で考慮すべき点について検討するとともに,多色イメージングの今後の方向性について議論したい.(著者抄録)

Language：Japanese   Publisher：(公社)におい・かおり環境協会  

嗅覚系において,個々のにおい分子は約400種類存在する嗅覚受容体の組み合わせによって認識される.一方で,複数のにおい分子が混ざった際にこれらがどのように嗅覚受容体に作用し,認識されるのかについては十分に理解されてこなかった.近年,生体イメージングによるハイスループット解析が可能となり,においの混合物が嗅神経細胞においてどのような応答を生じるのかが明らかになってきた.本稿では,複数のにおい分子の混合物が嗅覚受容体に作用した際に生じる拮抗作用と相乗効果について解説するとともに,においの混合物の識別機構について論じる.また,最近報告された嗅覚受容体の立体構造解析から得られた示唆についても議論する.(著者抄録)

Publisher：Cold Spring Harbor Laboratory  

ABSTRACT

Fluorescence imaging is widely used for the mesoscopic mapping of neuronal connectivity. However, neurite reconstruction is challenging, especially when neurons are densely labelled. Here we report a strategy for the fully automated reconstruction of densely labelled neuronal circuits. Firstly, we established stochastic “super-multicolour” labelling with up to seven different fluorescent proteins using the Tetbow method. With this method, each neuron was labelled with a unique combination of fluorescent proteins, which were then imaged and separated by linear unmixing. We also established an automated neurite reconstruction pipeline based on the quantitative analysis of multiple dyes (QDyeFinder). To classify colour combinations, we used a newly developed unsupervised clustering algorithm, dCrawler, in which data points in multi-dimensional space were clustered based on a given threshold distance. Our new strategy allows for the reconstruction of neurites for up to hundreds of neurons at a millimetre scale without manual tracing.

DOI： 10.1101/2022.10.20.512984

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Language：Japanese  

Language：Japanese  

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BMPR-2 gates activity-dependent stabilization of dendrites during mitral cell remodeling
<title>SUMMARY</title>Developing neurons initially form excessive neurites and then remodel them based on molecular cues and neuronal activity. Developing mitral cells in the olfactory bulb initially extend multiple primary dendrites. They then stabilize single primary dendrites, while eliminating others. However, the mechanisms underlying the selective dendrite remodeling remain elusive. Using CRISPR/Cas9-based knockout screening combined with <italic>in utero</italic> electroporation, we identified BMPR-2 as a key regulator for the selective dendrite stabilization. <italic>Bmpr2</italic> knockout and its rescue experiments show that BMPR-2 inhibits LIMK without ligands and thereby facilitates dendrite destabilization. In contrast, the overexpression of antagonists and agonists indicate that ligand-bound BMPR-2 stabilizes dendrites, most likely by releasing LIMK. Using genetic and FRET imaging experiments, we also demonstrate that free LIMK is activated by NMDARs via Rac1, facilitating dendrite stabilization through F-actin formation. Thus, the selective stabilization of mitral cell dendrites is ensured by concomitant inputs of BMP ligands and neuronal activity.

DOI： 10.1101/2020.10.30.358861

Language：Japanese  

Language：English  

Spontaneous activity generated within the olfactory bulb establishes the discrete wiring of mitral cell dendrites
<title>ABSTRACT</title>In the mouse olfactory bulb, sensory information detected by ∼1,000 types of olfactory sensory neurons (OSNs) is represented by the glomerular map. The second-order neurons, mitral and tufted cells, connect a single primary dendrite to one glomerulus. This forms discrete connectivity between the ∼1,000 types of input and output neurons. It has remained unknown how this discrete dendrite wiring is established during development. We found that genetically silencing neuronal activity in mitral cells, but not from OSNs, perturbs the dendrite pruning of mitral cells. <italic>In vivo</italic> calcium imaging of awake neonatal animals revealed two types of spontaneous neuronal activity in mitral/tufted cells, but not in OSNs. Pharmacological and knockout experiments revealed a role for glutamate and NMDARs. The genetic blockade of neurotransmission among mitral/tufted cells reduced spontaneous activity and perturbed dendrite wiring. Thus, spontaneous network activity generated within the olfactory bulb self-organizes the parallel discrete connections in the mouse olfactory system.

DOI： 10.1101/625616

Language：Japanese  

Language：Japanese  

Language：Japanese  

Language：Japanese  

Language：English  

DOI： 10.21769/BioProtoc

Language：Japanese  

Language：Japanese  

神経回路機能や発達過程を理解するには、まずその構造的基盤を明らかにすることが必須である。近年、GFPをはじめとする蛍光タンパク質や遺伝子導入技術が発展したことで、神経細胞の形態や接続様式の可視化が容易になった。さらに、こうした蛍光タンパク質の蛍光を保持しながら組織を透明にする手法が開発され、神経回路構造を三次元的に解析することが可能となってきた。本稿では、蛍光タンパク質と組織透明化法を用いて神経回路構造を定量解析するためのアプローチについて紹介したい。(著者抄録)

Language：Others  

DOI： 10.7875/first.author.2017.144

Language：Others  

Language：English  

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Language：Japanese  

Language：Japanese  

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Axonal Wiring Specificity by Differential cAMP Levels in the Mouse Olfactory System (GE & Science Prize winning essay).

Language：Others  

Language：Japanese  

Audience： General,　Scientific,　Company,　Civic organization,　Governmental agency

Audience： General,　Scientific,　Company,　Civic organization,　Governmental agency

Audience： General,　Scientific,　Company,　Civic organization,　Governmental agency

Audience： General,　Scientific,　Company,　Civic organization,　Governmental agency

Type：Lecture

【脳科学の達人2018】今井 猛 “脳の中で起こる究極の形作りを見る” 【第41回日本神経科学大会 市民公開講座】

においの調和 仕組み解明

プレス発表内容について

Tetbow: Bright Multicolor Labeling for Neuronal Tracing

Follow the Brainbow

脳細胞を明るく色分け 九州大 機能解明へ新手法開発

Photos of the Year

Where To Find Some Of The Most Stunning Neuroscience Images Of 2018

発火タイミングに基づく匂い識別 理研など仕組み解明

論文プレス発表内容について

におい識別の仕組み 解明か

ほ乳類の匂い識別解明

匂い識別 仕組み分かった 理研などの研究チーム発表

匂い識別、タイミング重要

匂い識別、タイミング重要＝神経の電気活動分析ー理研