一般口演（Oral）

Oral Olfiction 一般口演嗅覚

7月27日（土）16:30～16:45　第10会場（万代島ビル　6F　会議室） 3O-10e1-1 線虫の、特定の匂いに特異的な情報処理を可能にするPKG依存的な機構の解析 Takahiro Hino（日野喬央）¹，Manabi Fujiwara（藤原学）²，Takeshi Ishihara（石原健）² ¹九州大院システム生命分子遺伝 ²九州大学理学研究院生物科学部門 In the olfactory system of C. elegans, each single olfactory neuron expresses various olfactory receptors and senses many odorants. In C. elegans, exposure to the odorants sensed by AWA olfactory neuron causes attraction behavior. However, it is not clear whether information of these odorants induce the attraction behavior through common molecules or a common neural circuitry. A mutant of cGMP dependent protein kinase (EGL-4/PKG) shows a defect in attraction to a specific food-related odorant diacetyl, but not to other odorants sensed by AWA. We hypothesized that this difference may be caused by the distinct informational processing of AWA-sensed odorants in the olfactory circuitry, PKG-dependent or PKG-independent manner. Such a mechanism may enable worms to regulate the response to the specific odorant. To examine this hypothesis, we have analyzed the behavior and neuronal activities in PKG mutants. First, we examined the roles of the downstream circuitry of AWA olfactory neurons consisting of AIB, AIY and other interneurons, and found that ablation of AIB cause chemotaxis defect specifically to diacetyl but not to another AWA-sensed odorant. Ablation of AIB in the PKG mutant did not cause an additive effect in the chemotaxis defect to diacetyl. Thus, AIB may be important for processing of specific information for a particular odorant, and that PKG may function in this processing. We also found that AIY malfunction results in recovery of the chemotaxis defect of the PKG mutant, implying that in the absence of PKG, AIY act to disturb the informational processing that induces attraction. To understand the neural mechanisms, we analyzed Calcium responses of AWA, AIB and AIY under the diacetyl stimulation. In the PKG mutant, AWA responded normally to diacetyl, suggesting that PKG modulates a downstream signaling process of AWA upon the odor perception. As expected, the AIB response to diacetyl was attenuated in the PKG mutant, whereas, AIY response to diacetyl was apparently normal in the PKG mutant. Because it is known that AIB drives backward movement and AIY drives forward movement, one plausible model is that PKG controls the balance between these two conflicting drives for adequate movement in chemotaxis somehow specifically to diacetyl. The further studies including behavioral analysis of responses to the odorants will test the model. We hope to shed light on the mechanism for computing manifold olfactory information.		7月27日（土）16:45～17:00　第10会場（万代島ビル　6F　会議室） 3O-10e1-2 Selective Presynaptic Inhibition of Projection Neuron Axon Terminals by the APL neuron in the Mushroom body Calyx Kai Yang（Yang Kai），Yuelin Han（Han Yuelin） Institute of Neuroscience,Chinese Academy of Science Many researchers have used the fruit fly Drosophila melanogaster as a model organism to investigate how olfactory information is transformed through different stage of olfactory neurons. However, the specific modulating mechanisms during olfactory information flow remain largely unknown.We find that the APL neuron, a giant inhibitory interneuron projecting to the mushroom body, presynaptically inhibits the odor responses of projection neuron (PN) axon terminals in the mushroom body calyx. Taking advantage of HRP-labeled 3D EM reconstruction, we can efficiently and accurately recognize the APL neurites and PN terminals and resolve the ultra-structure connectivity between them with a region of mushroom body calyx.We found that the APL-input PN terminals has smaller relative active zone number(active zone number/bouton size) than that of Non-APL-input PN terminals, which suggests that APL inputs to PN terminals are inhibitory. Furthermore,the APL neurites are more likely to provide inputs to PN terminals with a larger size, and that may explain the former finding that preventing neuron transmission of PN leading to increased bouton size.We also found that the APL neuron has more inputs to dense core vesicle(DCV) PNs,which hints that APL neuron may influence the neuropeptide release of PN terminals. By tracing a number of putative KC neurites connected with the identified APL neurites and PN terminals,we found that APL neuron mainly executes lateral inhibition among those glomeruli distant from one another, while rarely perform feedback inhibition within one single microglomerulus. Physiologically, suppressing APL neuron with tetanus toxin resulted in significant increase in the fraction of odor responsive PN terminals among all PN terminals.and photo-activation of the APL neuron significantly decreased the odor response of a fraction of PN terminals. Furthermore,the inhibited PN terminals during photo-activating has odor selectivity. Taken together, we find that APL neuron executes selective presynaptic inhibition to PN terminals in the mushroom body calyx. Take former findings about olfactory adaption into consideration, like decreased PN response and increased bouton size in the mushroom body calyx (Ulrike Pech et al. 2015), we propose that the presynaptic inhibition from APL neuron to PN terminals plays a role in olfactory adaptation in fly.

7月27日（土）17:00～17:15　第10会場（万代島ビル　6F　会議室） 3O-10e1-3 ラット梨状皮質ニューロンは匂いと「匂い経験」を紐づける: Go/No-Go学習および逆転学習における多彩な応答様式と、そのポピュレーションGo/No-Go相関表現 Yuta Tanisumi（谷隅勇太）^1,2，Kazuki Shiotani（塩谷和基）^1,2，Keiji Miura（三浦佳二）³，Junya Hirokawa（廣川純也）¹，Yoshio Sakurai（櫻井芳雄）¹，Hiroyuki Manabe（眞部寛之）¹ ¹同志社大院脳研究 ²日本学術振興会特別研究員DC1 ³関西学院大 The piriform cortex, also known as the association cortex, is capable of integrating incoming olfactory information with top-down input from higher order regions. However, it still remains a mystery as to how these top-down signals are expressed in the piriform cortex and associated with information relative to odor stimulus identity. As piriform cortex activity measurements - through odor-inducing behaviors and sampling - have not been studied extensively, here we recorded neural ensemble activity in the anterior piriform cortex (aPC) of freely moving rats performing a go/no-go association task using four cue-odors and its reversal. Specifically, in each session, two odors induced the rat to enter the reward port (go trial), and another two induced the rat to stay near the odor port to wait for the next trial (no-go trial). Our findings revealed that a subset of neurons responded considerably to the odor presentation phase, in addition, the most of them also responded to the following odor-induced behavioral events: the movement to the reward port, the expectation of the rewards, the consumption of the rewards and the waiting on no-go trials. Furthermore, they have a positive correlation between the selectivity for go-cue odors and go-behavioral events, as well as no-go-cue odors and no-go-behavioral events, suggesting odor-event associative encodings in aPC populations. Finally, rats were applied to a reversal of the odor-outcome associations. Across the reversal learning, many odor-event selective neurons maintained the event-selective firings respectively, whereas the odor-selective firings during the odor presentation phase exhibited various changes in their firing patterns. Interestingly enough, aPC populations showed a positive correlation to the odor-event associative encodings after rats acquired the reversal problem. Based on these results, we speculate that aPC neurons have an important role in the associative integration between flexible odor representations and steady top-down signals related to odor-induced learned behaviors.		7月27日（土）17:15～17:30　第10会場（万代島ビル　6F　会議室） 3O-10e1-4 マウス嗅覚系の神経回路形成と意思決定の分子機構 Hirofumi Nishizumi（西住裕文），Nobuko Inoue（井上展子），Kasumi Inokuchi（井ノ口霞），Hitoshi Sakano（坂野仁）福井大学医学部高次脳機能領野 Topography of an olfactory map is established by axon-axon interactions of olfactory sensory neurons (OSNs) using multiple sets of Neuropilin (Nrp), Semaphorin (Sema), and Plexin (Plxn) molecules. During the process of OSN projection to the olfactory bulb (OB), odor information is roughly sorted into two distinct qualities, aversive and attractive, with the aid of an axon-guidance receptor Nrp2 and its repulsive ligand Sema3F. Although the primary projection takes place independently from second-order neurons, mitral and tufted (M/T) cells, OSNs have to make proper connections to M/T cells to make the olfactory circuit functional. How do the M/T cells find their partner glomeruli for synapse formation with OSN axons? We analyzed dendrite connection of M/T cells in various mutant mice in which glomerular formation is perturbed. Our results support the ""proximity model"", whereby M/T cells tend to connect primary dendrites to the nearest neighboring glomeruli regardless of their odorant-receptor identity. An activity-dependent signaling molecule Sema7A and its receptor PlxnC1 are essential for triggering the olfactory synapse formation. We then studied how mitral-cell (MC) axons are guided to the amygdala for quality decisions of odor information. We found that Nrp2⁺ MCs play crucial roles in transmitting attractive social signals from the posteroventral OB to the anterior region of the medial amygdala (MeA). Sema3F regulates both migration of Nrp2⁺ MCs to the posteroventral OB and their axonal projection to the anterior MeA. We also found that aversive/fear signals are transmitted from the posterodorsal OB to the medial and posterior regions of the cortical amygdala by Nrp2^- MCs. Our in utero electroporation experiment demonstrates that activation of a single axon guidance gene, Nrp2, is sufficient for instructing hard-wired circuit formation to mediate attractive social responses in the mouse olfactory system.