一般口演（若手道場）
若手道場 学習、記憶および可塑性
Wakate Dojo: Learning, Memory and Plasticity
座長：山中 宏二（名古屋大学 環境医学研究所）・吉田 祥子（豊橋技術科学大学） |
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| 2022年7月1日 10:00～10:15 沖縄コンベンションセンター 会議場B2 第5会場
2WD05m2-01
キイロショウジョウバエにおける経験依存的な歌の嗜好性を制御するGABAニューロンの同定
An identification of GABAergic neurons that regulate an experience-dependent song preference in Drosophila melanogaster.
*井本 圭亮(1)、田中 良弥(1)、大橋 拓朗(1)、石川 由希(1)、上川内 あづさ(1)
1. 名古屋大学
*Keisuke Imoto(1), Ryoya Tanaka(1), Takuro Ohashi(1), Yuki Ishikawa(1), Azusa Kamikouchi(1)
1. Nagoya University
Keyword: EXPERIENCE, AUDITORY, RECEPTIVITY, GABA
Sound experiences during development have a significant impact on their later sound discrimination in songbirds and humans. In the fruit fly, Drosophila melanogaster, sound discrimination is also affected by experiences. This study aims to shed light on the neural mechanisms underlying the experience-dependent sound discrimination ability. During courtship, male flies vibrate their wings to play a courtship song. This song makes the females more receptive for copulation. A previous study showed that behavioral response to heterospecific sound is modulated by auditory experience (Li et al., 2018); females that have no experiences of hearing the conspecific song after eclosion loose the preference between conspecific and heterospecific songs. This suggests that song experience after eclosion tunes the song preference of females. This phenotype is called “song preference learning”. Inhibiting the expression of Gad1, a synthetic enzyme of GABA, prevents the change in song preference with experience (Li et al., 2018), suggesting that GABA is required for song preference learning. However, the responsible GABAergic neurons have not yet been identified. To narrow down the responsible neurons, we combined the song preference learning paradigm with an intersection method to suppress GABA productions in smaller subsets of GABAergic neurons. By knocking down the expression of Gad1, we found that ~3 GABAergic neurons / hemisphere may be responsible for song preference learning. We also found that knockdown of Neuropeptide F receptor (NPFR) in GABAergic neurons reduced song preference learning, suggesting that NPFR in GABAergic neurons may also be involved in song preference learning. | | 2022年7月1日 10:15～10:30 沖縄コンベンションセンター 会議場B2 第5会場
2WD05m2-02
異種間ハイブリッドソングバードを用いた発声学習個体差の神経分子基盤
Neurogenetic mechanism underlying individuality in vocal learning in F1 hybrid songbirds
*柴田 ゆき野(1)、田路 矩之(2)、郷 康広(3)、辰本 将司(3)、石川 裕恵(3)、和多 和宏(1,2)
1. 北海道大学 大学院生命科学院、2. 北海道大学 大学院理学研究院、3. 自然科学研究機構 生命創成探究センター
*Yukino Shibata(1), Noriyuki Toji(2), Yasuhiro Go(3), Syoji Tatsumoto(3), Hiroe Ishikawa(3), Kazuhiro Wada(1,2)
1. Hokkaido University Graduate School of Life Science, 2. Hokkaido University Faculty of Science, 3. Exploratory Research Center on Life and Living Systems
Keyword: individual difference, vocal learning, hybrids, genetic factors
How do genetic factors affect individuality in complex motor skill learning? To tackle this question, we developed an animal model system using interspecific first-generation (F1) hybrid songbirds between zebra finch (Taeniopygia guttata) and cherry finch (Neochmia modesta). These two parental species are closely related songbird species, but they produce different characteristic songs at species-specific syllable acoustics and sequence. We tutored the F1 hybrid juveniles by playing back both parental species songs in a controlled environment. The F1 hybrid juveniles developed their songs with individual differences in learned syllable numbers. The range of individual differences in learned syllable numbers was more extensive than ones of their parental species. Notably, some F1 hybrids learned more syllables than both parental species did. In addition, F1 hybrids showed learning ability towards different species other than their parental species. These results suggest that apart genetic background from father and mother generate more divergent phenotypes in learned behaviors. To elucidate the neural basis underlying individual differences in learning, we are now investigating anatomical and transcriptomic differences in the song system, the neural circuit specialized for song learning and production. First, we focus on the vocal motor pathway regulating learned syllable acoustics and sequence patterns. In the vocal motor pathway, syllable learning achievement was not correlated with song nuclei size and neuron numbers. Instead, the single-cell RNA sequencing revealed the transcriptional signatures at specific cell types in the vocal motor song nuclei. These results suggest that, in specific cell types, differentiated transcription in the song system is associated with individuality in song learning. | | 2022年7月1日 10:30～10:45 沖縄コンベンションセンター 会議場B2 第5会場
2WD05m2-03
Visualization of individual active zone scaffold remodeling in the fly brain
*Hongyang Wu(1), Shu Kondo(2), Nobuhiro Yamagata(1), Hiromu Tanimoto(1)
1. Grad Sch Life Sci, Tohoku Univ, Sendai, Japan, 2. Invertebrate Genetic Lab, National Institute of Genetics
Keyword: ASSOCIATIVE LEARNING, SYNAPTIC PLASTICITY, KENYON CELL, ACTIVE ZONE
Substantial evidence indicates that memory formation involves postsynaptic structural modification of neurons which leads to altered circuit patterns or output consequences. In contrast, structural plasticity on the presynaptic side remains largely unknown. Considering that learning-induced changes in nanostructures take place only in selective cell populations, endogenous presynaptic proteins need to be specifically visualized in target cells. To this end, we tagged endogenous Bruchpilot (Brp) proteins, a key component of the Drosophila cytomatrix of active zones, with a split GFP, and visualized individual active zones only in a group of neurons by expressing the complementary GFP fragment. We here demonstrate individual Brp aggregates at the single-cell resolution in vivo. Furthermore, we applied this system to visualize active zones only in Kenyon cells (KCs) to study the synaptic reorganization in associative learning. KCs were shown to the site of memory formation by undergoing associative plasticity between odor cues and electric shock punishment. Strikingly, we found that learning-induced active zone remodeling was transient and locally regulated along the compartments of KC axons. These results suggest that associative learning induces parallel structural plasticity within KCs by spatially segmenting the synaptic sites. | | 2022年7月1日 10:45～11:00 沖縄コンベンションセンター 会議場B2 第5会場
2WD05m2-04
神経ペプチドNLP-47とその受容体GNRR-1は、線虫C. elegansの嗅覚学習の忘却を促進する
Neuropeptide NLP-47 and its receptor GNRR-1 accelerate forgetting of olfactory memory in C. elegans
*大西 湧己(1)、Teo Jamine(1)、北園 智弘(1)、石原 健(1,2)
1. 九州大学 大学院システム生命科学府、2. 九州大学 理学研究院 生物科学部門
*Yuuki Onishi(1), Jamine Teo(1), Tomohiro Kitazono(1), Takeshi Ishihara(1,2)
1. Graduate School of Systems Life Sciences, Kyushu University, Fukuoka, Japan, 2. Department of Biology, School of Sciences, Kyushu University, Fukuoka, Japan
Keyword: Memory Forgetting, C. elegans, Neuropeptide, GnRH receptor
Animals acquire and store information as memories that are required for their behavior and decision-making. To mitigate effects of old information stored in their brain, they must forget some dispensable memories. However, its molecular mechanism is still unclear. The roundworm Caenorhabditis elegans (C. elegans) is highly attracted to some odorants such as diacetyl, although, after prolonged exposure to odorants without food, the animals adapt to the odorants and show weak chemoattraction. The adapted animals can recover their chemoattraction after the cultivation on food for several hours. We are analyzing this behavioral change as a model of forgetting. Previously, our studies showed that TIR-1/JNK-1 pathway in AWC sensory neurons accelerates forgetting of olfactory adaptation, through releasing of “forgetting signals”. However, the molecular basis of “forgetting signals” remains elusive. In this study, firstly, the behavioral analyses of mutants defective in neuropeptide processing enzyme suggested that neuropeptides might be responsible for forgetting signals. Next, to identify neuropeptides that serve as “forgetting signals” from AWC sensory neuron, we searched for genes by using CeNGEN (C. elegans Neuronal Gene Expression Network, a dataset of single-cell RNA sequencing), and found 15 candidates. By using CRISPR-Cas9, we created these mutants and analyzed their forgetting phenotype. Among these candidates, neuropeptide nlp-47 mutants showed forgetting defect. Moreover, injection of wild-type nlp-47 genomic fragments could recover the forgetting phenotype in the mutants. These suggest that neuropeptide NLP-47 is responsible for accelerating forgetting. Furthermore, NLP-47 receptor GNRR-1, an orthologue of human GnRH receptor, may also be involved in promoting forgetting because gnrr-1 mutants showed the forgetting defect. Further analyses of these factors will reveal how memory forgetting are regulated by signaling pathways including “forgetting signals”. | |
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