研究者データベース

西野 浩史(ニシノ ヒロシ)
電子科学研究所 附属社会創造数学研究センター
助教

基本情報

所属

  • 電子科学研究所 附属社会創造数学研究センター

職名

  • 助教

学位

  • 理学博士(岡山大学)

ホームページURL

科研費研究者番号

  • 80332477

J-Global ID

研究キーワード

  • 神経解剖学   聴覚   フェロモン   嗅覚   害虫防除   バイオミメティクス   感覚生理学   昆虫生理学   神経行動学   

研究分野

  • ライフサイエンス / 動物生理化学、生理学、行動学
  • ライフサイエンス / 神経形態学
  • ライフサイエンス / 基盤脳科学

所属学協会

  • 日本比較生理生化学会   日本動物学会   国際神経行動学会   

研究活動情報

論文

  • Masahiro Komatsu, Keigo Kurihara, Susumu Saito, Mana Domae, Naoki Masuya, Yuta Shimura, Shunichiro Kajiyama, Yuna Kanda, Kouki Sugizaki, Kouji Ebina, Osamu Ikeda, Yudai Moriwaki, Naohiro Atsumi, Katsuyoshi Abe, Tadashi Maruyama, Satoshi Watanabe, Hiroshi Nishino
    Zoological letters 6 1 15 - 15 2020年11月26日 [査読有り]
     
    Insect outbreaks often occur in the absence of natural enemies and in the presence of excess suitable host materials. Outbreaks of gypsy moths are especially problematic in remote areas located in high-latitude regions in Japan because the majority of adults emerge during the short summer season and initiate synchronous mass flight toward artificial lights. The aggregation of moths in public facilities not only is an annoyance to visitors but also permits the establishment of new populations the following year. The aim of this study was to establish a method to reduce the numbers of large moths that are attracted to lights in the rest areas of expressways in Hokkaido based on the results of research on their behavioral ecology and physiology. First, we conducted extensive insect surveys using light traps that emit light at different wavelengths; the traps were set along the expressways in the summers of 2014-2018. The insects attracted to the light were roughly classified into those showing a preference for broadband light wavelengths (from UV-A to green) and short light wavelengths (from UV-A to blue). The former included aquatic insects and winged ants, and the latter included moths and beetles. Next, we analyzed correlations between moth emergence and daily meteorological data. When gypsy moths were abundant during an outbreak, the daily catch of gypsy moths was positively correlated with the highest ambient temperature on the catch day but not with the visibility range, wind speed, or moon phase. In contrast, the daily catch of oak silkmoths did not correlate with any of these parameters. Our results provide guidance for the management of forest insects inhabiting cool-temperate to subarctic regions based on light wavelengths with reference to weather variables.
  • Marco Paoli, Hiroshi Nishino, Einat Couzin-Fuchs, C Giovanni Galizia
    The Journal of experimental biology 223 Pt 3 2020年02月03日 [査読有り][通常論文]
     
    The general architecture of the olfactory system is highly conserved from insects to humans, but neuroanatomical and physiological differences can be observed across species. The American cockroach, inhabiting dark shelters with a rather stable olfactory landscape, is equipped with long antennae used for sampling the surrounding air-space for orientation and navigation. The antennae's exceptional length provides a wide spatial working range for odour detection; however, it is still largely unknown whether and how this is also used for mapping the structure of the olfactory environment. By selectively labelling antennal lobe projection neurons with a calcium-sensitive dye, we investigated the logic of olfactory coding in this hemimetabolous insect. We show that odour responses are stimulus specific and concentration dependent, and that structurally related odorants evoke physiologically similar responses. By using spatially confined stimuli, we show that proximal stimulations induce stronger and faster responses than distal ones. Spatially confined stimuli of the female pheromone periplanone B activate a subregion of the male macroglomerulus. Thus, we report that the combinatorial logic of odour coding deduced from holometabolous insects applies also to this hemimetabolous species. Furthermore, a fast decrease in sensitivity along the antenna, not supported by a proportionate decrease in sensillar density, suggests a neural architecture that strongly emphasizes neuronal inputs from the proximal portion of the antenna.
  • Naomi Takahashi, Hiroshi Nishino, Mana Domae, Makoto Mizunami
    The Journal of neuroscience : the official journal of the Society for Neuroscience 39 44 8690 - 8704 2019年10月30日 [査読有り][通常論文]
     
    The basic organization of the olfactory system has been the subject of extensive studies in vertebrates and invertebrates. In many animals, GABA-ergic neurons inhibit spike activities of higher-order olfactory neurons and help sparsening of their odor representations. In the cockroach, two different types of GABA-immunoreactive interneurons (calyceal giants [CGs]) mainly project to the base and lip regions of the calyces (input areas) of the mushroom body (MB), a second-order olfactory center. The base and lip regions receive axon terminals of two different types of projection neurons, which receive synapses from different classes of olfactory sensory neurons (OSNs), and receive dendrites of different classes of Kenyon cells, MB intrinsic neurons. We performed intracellular recordings from pairs of CGs and MB output neurons (MBONs) of male American cockroaches, the latter receiving synapses from Kenyon cells, and we found that a CG receives excitatory synapses from an MBON and that odor responses of the MBON are changed by current injection into the CG. Such feedback effects, however, were often weak or absent in pairs of neurons that belong to different streams, suggesting parallel organization of the recurrent pathways, although interactions between different streams were also evident. Cross-covariance analysis of the spike activities of CGs and MBONs suggested that odor stimulation produces synchronized spike activities in MBONs and then in CGs. We suggest that there are separate but interactive parallel streams to process odors detected by different OSNs throughout the olfactory processing system in cockroaches.SIGNIFICANCE STATEMENT Organizational principles of the olfactory system have been the subject of extensive studies. In cockroaches, signals from olfactory sensory neurons (OSNs) in two different classes of sensilla are sent to two different classes of projection neurons, which terminate in different areas of the mushroom body (MB), each area having dendrites of different classes of MB intrinsic neurons (Kenyon cells) and terminations of different classes of GABAergic neurons. Physiological and morphological assessments derived from simultaneous intracellular recordings/stainings from GABAergic neurons and MB output neurons suggested that GABAergic neurons play feedback roles and that odors detected by OSNs are processed in separate but interactive processing streams throughout the central olfactory system.
  • Mana Domae, Masazumi Iwasaki, Makoto Mizunami, Hiroshi Nishino
    Neuroscience letters 708 134320 - 134320 2019年08月24日 [査読有り][通常論文]
     
    Female Periplaneta americana cockroaches emit two cooperatively working pheromone components, periplanone-B (PB) as a long-range attractant and periplanone-A (PA) as a short-range arrestant, and males develop enlarged glomeruli for processing them separately in the first-order olfactory center. Using intracellular recordings and neuronal labelings, we found that the Turkestan cockroach, Blatta lateralis, which is phylogenetically close to P. americana but having adapted to inground habitats, has an extraordinary large glomerulus. This is caused by drastic enlargement of the PB-responsive glomerulus but not the PA-responsive glomerulus during the late nymphal stage. The output neuron from the macroglomerulus is sensitive to both PA and PB, at a dose of only 0.1 fg. Nevertheless, B. lateralis males never exhibited courtship rituals in response to the presentation of periplanones or natural sex pheromone but exhibited courtship rituals in response to antennal contact with females. Our findings indicate that the unique behavioral ecology and habitats of B. lateralis are related to the functional unification of the pheromone processing system, opposite to the functional differentiation that often underlies species diversification.
  • Nishino H, Domae M, Takanashi T, Okajima T
    Cell and tissue research 377 2 193 - 214 2019年03月 [査読有り][通常論文]
  • Watanabe H, Koike Y, Tateishi K, Domae M, Nishino H, Yokohari F
    The Journal of comparative neurology 526 16 2683 - 2705 2018年11月 [査読有り][通常論文]
     
    In the cockroach Periplaneta americana, to represent pheromone source in the receptive space, axon terminals of sex pheromone-receptive olfactory sensory neurons (pSNs) are topographically organized within the primary center, the macroglomerulus, according to the peripheral locations of sex pheromone-receptive single walled (sw)-B sensilla. In this study, we sought to determine when and where pSNs emerge in the nymphal antenna. We revealed two different pSN proliferation patterns that underlie the formation of topographic organization in the macroglomerulus. In nymphal antennae, which lack sw-B sensilla, pSNs are identified in the shorter sensilla, termed sw-A sensilla. Because new sw-A sensilla emerge on the proximal antenna at every molt, topographic organization in the macroglomerulus must be formed by adding axon terminals of newly emerged pSNs to the lateral region in the macroglomerulus at each molt. At the final molt, a huge number of new sw-B sensilla appeared throughout the whole antenna. Sw-B sensilla in the proximal part of the adult antenna were newly formed during the last instar stage, whereas those located in the distal antenna were transformed from sw-A sensilla. This transformation was accompanied by an increase in the number of pSNs. Axon terminals of newborn pSNs in new sw-B sensilla were recruited to the lateral part of the macroglomerulus, whereas those of newborn pSNs in transformed sw-B sensilla were recruited to the macroglomerulus according to the sensillar location. These mechanisms enable an increase in sensitivity to sex pheromone in adulthood while retaining the topographic map formed during the postembryonic development.
  • Hiroshi Nishino, Masazumi Iwasaki, Marco Paoli, Itsuro Kamimura, Atsushi Yoritsune, Makoto Mizunami
    Current Biology 28 4 600 - 608.e3 2018年02月19日 [査読有り][通常論文]
     
    Animals rely on olfaction to navigate through complex olfactory landscapes, but the mechanisms that allow an animal to encode the spatial structure of an odorous environment remain unclear. To acquire information about the spatial distribution of an odorant, animals may rely on bilateral olfactory organs and compare side differences of odor intensity and timing [1–6] or may perform spatial and temporal signal integration of subsequent samplings [7]. The American cockroach can efficiently locate a source of sex pheromone even after the removal of one antenna, suggesting that bilateral comparison is not a prerequisite for odor localization in this species [8, 9]. Cognate olfactory sensory neurons (OSNs) originating from different locations on the flagellum, but bearing the same olfactory receptor, converge onto the same glomerulus within the antennal lobe, which is thought to result in a loss of spatial information. Here, we identified 12 types of pheromone-responsive projection neurons (PNs), each with spatially tuned receptive field. The combination of (1) the antennotopic organization of OSNs terminals and (2) the stereotyped compartmentalization of PNs’ dendritic arborization within the macroglomerulus (MG), allows encoding the spatial position of the pheromone. Furthermore, each PN type innervates a different compartment of the mushroom body, providing the means for encoding spatial olfactory information along the olfactory circuit. Finally, MG PNs exhibit both excitatory and inhibitory spatial receptive fields and modulate their responses based on changes in stimulus geometry. In conclusion, we propose a mechanism for encoding information on the spatial distribution of a pheromone, expanding both our understanding of odor coding and of the strategies insects adopt to localize a sexual mate. Nishino et al. describe how spatial information of pheromone distribution can be encoded in the cockroach olfactory circuit. They describe a class of projection neurons with subglomerular compartmentalization and distinct receptive fields along the antenna.
  • Hidehiro Watanabe, Hiroshi Nishino, Makoto Mizunami, Fumio Yokohari
    FRONTIERS IN NEURAL CIRCUITS 11 32  2017年05月 [査読有り][通常論文]
     
    In animals, sensory processing via parallel pathways, including the olfactory system, is a common design. However, the mechanisms that parallel pathways use to encode highly complex and dynamic odor signals remain unclear. In the current study, we examined the anatomical and physiological features of parallel olfactory pathways in an evolutionally basal insect, the cockroach Periplaneta americana. In this insect, the entire system for processing general odors, from olfactory sensory neurons to higher brain centers, is anatomically segregated into two parallel pathways. Two separate populations of secondary olfactory neurons, type1 and type2 projection neurons (PNs), with dendrites in distinct glomerular groups relay olfactory signals to segregated areas of higher brain centers. We conducted intracellular recordings, revealing olfactory properties and temporal patterns of both types of PNs. Generally, type1 PNs exhibit higher odorspecificities to nine tested odorants than type2 PNs. Cluster analyses revealed that odor-evoked responses were temporally complex and varied in type1 PNs, while type2 PNs exhibited phasic on-responses with either early or late latencies to an effective odor. The late responses are 30-40 ms later than the early responses. Simultaneous intracellular recordings from two different PNs revealed that a given odor activated both types of PNs with different temporal patterns, and latencies of early and late responses in type2 PNs might be precisely controlled. Our results suggest that the cockroach is equipped with two anatomically and physiologically segregated parallel olfactory pathways, which might employ different neural strategies to encode odor information.
  • Naomi Takahashi, Ko Katoh, Hidehiro Watanabe, Yuta Nakayama, Masazumi Iwasaki, Makoto Mizunami, Hiroshi Nishino
    JOURNAL OF COMPARATIVE NEUROLOGY 525 1 204 - 230 2017年01月 [査読有り][通常論文]
     
    Global inhibition is a fundamental physiological mechanism that has been proposed to shape odor representation in higher-order olfactory centers. A pair of mushroom bodies (MBs) in insect brains, an analog of the mammalian olfactory cortex, are implicated in multisensory integration and associative memory formation. With the use of single/multiple intracellular recording and staining in the cockroach Periplaneta americana, we succeeded in unambiguous identification of four tightly bundled GABA-immunoreactive giant interneurons that are presumably involved in global inhibitory control of the MB. These neurons, including three spiking neurons and one nonspiking neuron, possess dendrites in termination fields of MB output neurons and send axon terminals back to MB input sites, calyces, suggesting feedback roles onto the MB. The largest spiking neuron innervates almost exclusively the basal region of calyces, while the two smaller spiking neurons and the second-largest nonspiking neuron innervate more profusely the peripheral (lip) region of the calyces than the basal region. This subdivision corresponds well to the calycal zonation made by axon terminals of two populations of uniglomerular projection neurons with dendrites in distinct glomerular groups in the antennal lobe. The four giant neurons exhibited excitatory responses to every odor tested in a neuron-specific fashion, and two of the neurons also exhibited inhibitory responses in some recording sessions. Our results suggest that two parallel olfactory inputs to the MB undergo different forms of inhibitory control by the giant neurons, which may, in turn, be involved in different aspects of odor discrimination, plasticity, and state-dependent gain control. J. Comp. Neurol. 525:204-230, 2017. (c) 2016 Wiley Periodicals, Inc.
  • Ko Katoh, Masazumi Iwasaki, Shouhei Hosono, Atsushi Yoritsune, Masanori Ochiai, Makoto Mizunami, Hiroshi Nishino
    Zoological Letters 3 1 3  2017年 [査読有り][通常論文]
     
    Background Facultative parthenogenesis, seen in many animal phyla, is a reproductive strategy in which females are able to generate offspring when mating partners are unavailable. In some subsocial and eusocial insects, parthenogenesis is often more prevalent than sexual reproduction. However, little is known about how social cooperation is linked to the promotion of parthenogenesis. The domiciliary cockroach Periplaneta americana is well-suited to addressing this issue as this species belongs to the superfamily Blattoidea, which diverged into eusocial termites and shows facultative parthenogenesis. Results We studied environmental factors that influence asexual production of ootheca using behavioral assays in P. americana. When more than three virgin females immediately after the imaginal molt were kept together in a small sealed container, they tended to produce egg cases (oothecae) via parthenogenesis earlier than did isolated females, resulting in apparent synchronization of ootheca production, even among females housed in different containers. In contrast, virgin females housed with genitalia-ablated males or group-housed females with antennae ablated did not significantly promote ootheca production compared to isolated females. Daily addition of the primary sex pheromone component to the container did not promote ootheca production in isolated females. Another line of study showed that grouped females make parthenogenesis more sustainable than previously known a founder colony of 15 virgin females was sufficient to produce female progeny for a period of more than three years. Conclusions Group-housed females promote and stabilize asexual ootheca production compared to isolated females, and that this promotion is triggered by female-specific chemosensory signals (other than sex pheromone) primarily detected by antennae. Promotion of ootheca production between females is likely to be an early stage of social cooperation, reminiscent of the foundation and maintenance of a colony by female pairs in the eusocial termite Reticulitermes speratus.
  • Hiroshi Nishino, Hiromi Mukai, Takuma Takanashi
    CELL AND TISSUE RESEARCH 366 3 549 - 572 2016年12月 [査読有り][通常論文]
     
    Hemipteran insects use sophisticated vibrational communications by striking body appendages on the substrate or by oscillating the abdominal tymbal. There has been, however, little investigation of sensory channels for processing vibrational signals. Using sensory nerve stainings and low invasive confocal analyses, we demonstrate the comprehensive neuronal mapping of putative vibration-responsive chordotonal organs (COs) in stink bugs (Pentatomidae and Cydinidae) and cicadas (Cicadidae). The femoral CO (FCO) in stink bugs consists of ventral and dorsal scoloparia, homologous to distal and proximal scoloparia in locusts, which are implicated in joint movement detection and vibration detection, respectively. The ligament of the dorsal scoloparium is distally attached to the accessory extensor muscle, whereas that of the ventral scoloparium is attached to a specialized tendon. Their afferents project to the dorso-lateral neuropil and the central region of the medial ventral association center (mVAC) in the ipsilateral neuromere, where presumed dorsal scoloparium afferents and subgenual organ afferents are largely intermingled. In contrast, FCOs in cicadas have decreased dorsal scoloparium neurons and lack projections to the mVAC. The tymbal CO of stink bugs contains four sensory neurons that are distally attached to fat body cells via a ligament. Their axons project intersegmentally to the dorsal region of mVACs in all neuromeres. Together with comparisons of COs in different insect groups, the results suggest that hemipteran COs have undergone structural modification for achieving faster signaling of resonating peripheral tissues. The conserved projection patterns of COs suggest functional importance of the FCO and subgenual organ for vibrational communications.
  • Yoshitaka Hamanaka, Run Minoura, Hiroshi Nishino, Toru Miura, Makoto Mizunami
    PLOS ONE 11 8 e0160531  2016年08月 [査読有り][通常論文]
     
    The catecholamine dopamine plays several vital roles in the central nervous system of many species, but its neural mechanisms remain elusive. Detailed neuroanatomical characterization of dopamine neurons is a prerequisite for elucidating dopamine's actions in the brain. In the present study, we investigated the distribution of dopaminergic neurons in the brain of the American cockroach, Periplaneta americana, using two antisera: 1) an antiserum against dopamine, and 2) an antiserum against tyrosine hydroxylase (TH, an enzyme required for dopamine synthesis), and identified about 250 putatively dopaminergic neurons. The patterns of dopamine- and TH-immunoreactive neurons were strikingly similar, suggesting that both antisera recognize the same sets of "dopaminergic" neurons. The dopamine and TH antibodies intensively or moderately immunolabeled prominent brain neuropils, e.g. the mushroom body (memory center), antennal lobe (first-order olfactory center) and central complex (motor coordination center). All subdivisions of the mushroom body exhibit both dopamine and TH immunoreactivity. Comparison of immunolabeled neurons with those filled by dye injection revealed that a group of immunolabeled neurons with cell bodies near the calyx projects into a distal region of the vertical lobe, which is a plausible site for olfactory memory formation in insects. In the antennal lobe, ordinary glomeruli as well as macroglomeruli exhibit both dopamine and TH immunoreactivity. It is noteworthy that the dopamine antiserum labeled tiny granular structures inside the glomeruli whereas the TH antiserum labeled processes in the marginal regions of the glomeruli, suggesting a different origin. In the central complex, all subdivisions excluding part of the noduli and protocerebral bridge exhibit both dopamine and TH immunoreactivity. These anatomical findings will accelerate our understanding of dopaminergic systems, specifically in neural circuits underlying aversive memory formation and arousal, in insects.
  • Takanashi T, Fukaya M, Nakamuta K, Skals N, Nishino H
    Zoological letters 2 1 18  2016年08月 [査読有り][通常論文]
     
    Background: Vibrational senses are vital for plant-dwelling animals because vibrations transmitted through plants allow them to detect approaching predators or conspecifics. Little is known, however, about how coleopteran insects detect vibrations.Results: We investigated vibrational responses of the Japanese pine sawyer beetle, Monochamus alternatus, and its putative sense organs. This beetle showed startle responses, stridulation, freezing, and walking in response to vibrations below 1 kHz, indicating that they are able to detect low-frequency vibrations. For the first time in a coleopteran species, we have identified the sense organ involved in the freezing behavior. The femoral chordotonal organ (FCO), located in the mid-femur, contained 60-70 sensory neurons and was distally attached to the proximal tibia via a cuticular apodeme. Beetles with operated FCOs did not freeze in response to low-frequency vibrations during walking, whereas intact beetles did. These results indicate that the FCO is responsible for detecting low-frequency vibrations and mediating the behavioral responses. We discuss the behavioral significance of vibrational responses and physiological functions of FCOs in M. alternatus.Conclusions: Our findings revealed that substrate vibrations mediate behavioral responses via femoral chordotonal organs in M. alternatus.
  • Makoto Mizunami, Hiroshi Nishino, Fumio Yokohari
    FRONTIERS IN PHYSIOLOGY 7 150  2016年04月 [査読有り][通常論文]
     
    Thermosensation is critically important for survival of all animals. In the cockroach Periplaneta americana, thermoreceptor neurons on antennae and thermosensory interneurons in the antennal lobe have been characterized electrophysiologically, and recent studies using advanced transgenic technologies in the fruit fly Drosophila melanogaster have added much to the knowledge of these neurons, enabling us to discuss common principles of thermosensory processing systems in insects. Cockroaches and many other insects possess only one type of thermoreceptor neurons on antennae that are excited by cooling and inhibited by warming. In contrast, the antennae of fruit flies and other dipterans possess oppositely responding warm and cold receptor neurons. Despite differences in their thermoreceptive equipment, central processing of temperature information is much the same in flies and cockroaches. Axons of thermoreceptor neurons project to the margin of the antennal lobe and form glomeruli, from which cold, warm and cold-warm projection neurons originate, the last neurons being excited by both cooling and warming. Axons of antennal lobe thermosensory projection neurons of the antennal lobe terminate in three distinct areas of the protocerebrum, the mushroom body, lateral horn and posterior lateral protocerebrum, the last area also receiving termination of hygrosensory projection neurons. Such multiple thermosensory pathways may serve to control multiple forms of thermosensory behavior. Electrophysiological studies on cockroaches and transgenic approaches in flies are encouraged to complement each other for further elucidating general principles of thermosensory processing in the insect brain.
  • Hiroshi Nishino, Hidehiro Watanabe, Itsuro Kamimura, Fumio Yokohari, Makoto Mizunami
    NEUROSCIENCE LETTERS 595 35 - 40 2015年05月 [査読有り][通常論文]
     
    In contrast to visual, auditory, taste, and mechanosensory neuropils, in which sensory afferents are topographically organized on the basis of their peripheral soma locations, axons of cognate sensory neurons from different locations of the olfactory sense organ converge onto a small spherical neuropil (glomerulus) in the first-order olfactory center. In the cockroach Periplaneta americana, sex pheromone-sensitive afferents with somata in the antero-dorsal and postero-ventral surfaces of a long whip-like antenna are biased toward the anterior and posterior regions of a macroglomerulus, respectively. In each region, afferents with somata in the more proximal antenna project to more proximal region, relative to the axonal entry points. However, precise topography of afferents in the macroglomerulus has remained unknown. Using single and multiple neuronal stainings, we showed that afferents arising from anterior, dorsal, ventral and posterior surfaces of the proximal regions of an antenna were biased progressively from the anterior to posterior region of the macroglomerulus, reflecting chiasmatic axonal re-arrangements that occur immediately before entering the antennal lobe. Morphologies of individual afferents originating from the proximal antenna matched results of mass neuronal stainings, but their three-dimensional origins in the antenna were hardly predictable on the basis of the projection patterns. Such projection biases made by neuronal populations differ from strict somatotopic projections of antennal mechanosensory neurons in the same species, suggesting a unique sensory mechanism to process information about odor location and direction on a single antenna. (C) 2015 Elsevier Ireland Ltd. All rights reserved.
  • Mizunami M, Hamanaka Y, Nishino H
    Zoological letters 1 8  2015年02月 [査読有り][通常論文]
  • Toshio Ichikawa, Yoshihiro Toh, Kazuhiko Ohkubo, Hiroshi Nishino
    ZOOMORPHOLOGY 133 3 273 - 284 2014年09月 [査読有り][通常論文]
     
    Many insects have a pair of claws on each leg. The distribution of mechanoreceptors that monitor claw actions was examined in the tenebrionid beetle Zophobas atratus. Each claw has 25-45 campaniform sensilla (CS) that detect the claw's deformation due to substrate engagement. Five CS clusters are observed around the end of the 5th tarsomere (Ta5) in a concave, socket-like structure. The 1st cluster, containing 2-5 CS, is embedded in the unguifer to which the claws are articulated. The symmetrical 2nd and 3rd clusters, each containing two CS, are located bilaterally in the ventrolateral grooves of the sidewall of the socket, into which the unguis retractor plate slides. The 4th and 5th clusters, containing 1-2 CS with two hair sensilla, are localized near the ventrolateral ridges of the socket into which the basal portion of the claw is pressed during maximal claw flexion. In addition, Ta5 has a chordotonal organ of six sensory cells to monitor claw extension. These results suggest that the mechanoreceptor system may directly monitor the precise mechanical states of individual claws and provide the central nervous system with the sensory information required for fine feedback control of movements of the pretarsus and other leg segments for locomotion and other purposes.
  • Chihiro S. Matsumoto, Tomokazu Kuramochi, Yukihisa Matsumoto, Hidehiro Watanabe, Hiroshi Nishino, Makoto Mizunami
    Neuroscience Letters 541 4 - 8 2013年04月29日 [査読有り][通常論文]
  • Makoto Mizunami, Yukihisa Matsumoto, Hidehiro Watanabe, Hiroshi Nishino
    Handbook of Behavioral Neuroscience 22 549 - 560 2013年 [査読有り][通常論文]
     
    Crickets (Gryllus bimaculatus) and cockroaches (Periplaneta americana) have emerged as pertinent models for studying the neural basis of learning and memory. This is partly because they have excellent capabilities for olfactory and visual learning and partly because their rather large brains allow detailed physiological, pharmacological, and microsurgical analyses of the underlying neural mechanisms. Studies on crickets have documented the roles of octopaminergic and dopaminergic neurons in acquisition and retrieval of memory and have also shown a serial arrangement of the NO-cGMP cascade, cyclic nucleotide-gated channel, and calcium/calmodulin system for long-term memory formation. Studies on cockroaches suggest roles of the mushroom body in olfactory learning and visual place learning. Newer techniques, such as RNA interference (for crickets and cockroaches) and transgenesis (for crickets), have been successfully applied to these insects, which should help advance the study of cellular and molecular mechanisms underlying learning and memory. © 2013 Elsevier B.V.
  • Hiroshi Nishino, Masazumi Iwasaki, Itsuro Kamimura, Makoto Mizunami
    JOURNAL OF COMPARATIVE NEUROLOGY 520 15 3428 - 3445 2012年10月 [査読有り][通常論文]
     
    Many animals utilize sex pheromone for detecting conspecific mates. Sex pheromone is usually a blend of two or more components with similar chemical compositions. The pheromone receivers are equipped with localized olfactory glomeruli in the first-order olfactory center for specifically processing these pheromone components. In the American cockroach, Periplaneta americana, either periplanone A or periplanone B emitted by virgin females evokes identical sexual behaviors in males. The antennal lobes of adult male cockroaches have enlarged, neighboring A- and B-glomeruli, which preferentially process periplanones A and B, respectively. By using intracellular recording and staining of neurons in the same preparations, we provide the first detailed projection maps of output neurons (projection neurons; PNs) from the A-glomerulus and the B-glomerulus. Although both PNs project to the mushroom body calyces and the lateral horn, their proximities in the two centers largely differ: in the calyces, the axon terminals of the A-PN were located more predominantly in the periphery compared with those of the B-PN, whereas axon terminals of both PNs were highly congruent in the anteromedial region of the lateral horn. These results suggest that pheromone component signals are dispersed in the mushroom body for specific odor discrimination but are integrated in the lateral horn for generating behaviors common to the pheromone components. Stimulation of the ipsilateral antenna with various odors showed that the odor specificity of A-PN is higher than that of B-PN. The different developmental lineages of A- and B-PNs suggested by these results are discussed. J. Comp. Neurol. 520:34283445, 2012. (C) 2012 Wiley Periodicals, Inc.
  • Hidehiro Watanabe, S. Shuichi Haupt, Hiroshi Nishino, Michiko Nishikawa, Fumio Yokohari
    JOURNAL OF COMPARATIVE NEUROLOGY 520 8 1687 - 1701 2012年06月 [査読有り][通常論文]
     
    In vertebrates and many invertebrates, olfactory signals detected by peripheral olfactory receptor neurons (ORNs) are conveyed to a primary olfactory center with glomerular organization in which odor-specific activity patterns are generated. In the cockroach, Periplaneta americana, ORNs in antennal olfactory sensilla project to 205 unambiguously identifiable antennal lobe (AL) glomeruli that are classified into 10 glomerular clusters (T1T10 glomeruli) innervated by distinct sensory tracts. In this study we employed single sensillum staining techniques and investigated the topographic projection patterns of individual ORNs to elucidate the relationship between sensillum types and glomerular organization in the AL. Axons of almost all ORNs projected to individual glomeruli. Axons of ORNs in perforated basiconic sensilla selectively innervated the anterodorsal T1T4 glomeruli, whereas those in trichoid and grooved basiconic sensilla innervated the posteroventral T5T9 glomeruli. About 90% of stained ORNs in trichoid sensilla sent axons to the T5 glomeruli and more than 90% of ORNs in grooved basiconic sensilla innervated the T6, T8, and T9 glomeruli. The T5 and T9 glomeruli exclusively receive sensory inputs from the trichoid and grooved basiconic sensilla, respectively. All investigated glomeruli received convergent input from a single type of sensillum except F11 glomerulus in the T6 glomeruli, which was innervated from both trichoid and grooved basiconic sensilla. These results suggest that ORNs in distinct sensillum types project to glomeruli in distinct glomerular clusters. Since ORNs in distinct sensillum types are each tuned to distinct subsets of odorant molecules, the AL is functionally compartmentalized into groups of glomeruli. J. Comp. Neurol. 520:16871701, 2012. (C) 2011 Wiley Periodicals, Inc.
  • Chihiro Sato Matsumoto, Yukihisa Matsumoto, Hidehiro Watanabe, Hiroshi Nishino, Makoto Mizunami
    NEUROBIOLOGY OF LEARNING AND MEMORY 97 1 30 - 36 2012年01月 [査読有り][通常論文]
     
    Context-dependent discrimination learning, a sophisticated form of nonelemental associative learning, has been found in many animals, including insects. The major purpose of this research is to establish a method for monitoring this form of nonelemental learning in rigidly restrained insects for investigation of underlying neural mechanisms. We report context-dependent olfactory learning (occasion-setting problem solving) of salivation, which can be monitored as activity changes of salivary neurons in immobilized cockroaches, Periplaneta americana. A group of cockroaches was trained to associate peppermint odor (conditioned stimulus, CS) with sucrose solution reward (unconditioned stimulus, US) while vanilla odor was presented alone without pairing with the US under a flickering light condition (1.0 Hz) and also trained to associate vanilla odor with sucrose reward while peppermint odor was presented alone under a steady light condition. After training, the responses of salivary neurons to the rewarded peppermint odor were significantly greater than those to the unrewarded vanilla odor under steady illumination and those to the rewarded vanilla odor was significantly greater than those to the unrewarded peppermint odor in the presence of flickering light. Similar context-dependent responses were observed in another group of cockroaches trained with the opposite stimulus arrangement. This study demonstrates context-dependent olfactory learning of salivation for the first time in any vertebrate and invertebrate species, which can be monitored by activity changes of salivary neurons in restrained cockroaches. (C) 2011 Elsevier Inc. All rights reserved.
  • Hiroshi Nishino, Masazumi Iwasaki, Kouji Yasuyama, Hidenori Hongo, Hidehiro Watanabe, Makoto Mizunami
    ARTHROPOD STRUCTURE & DEVELOPMENT 41 1 3 - 16 2012年01月 [査読有り][通常論文]
     
    The cockroach Periplaneta americana is an evolutionary basal neopteran insect, equipped with one of the largest and most elaborate mushroom bodies among insects. Using intracellular recording and staining in the protocerebrum, we discovered two new types of neurons that receive direct input from the optic lobe in addition to the neuron previously reported. These neurons have dendritic processes in the optic lobe, projection sites in the optic tracts, and send axonal terminals almost exclusively to the innermost layer of the MB calyces (input site of MB). Their responses were excitatory to visual but inhibitory to olfactory stimuli, and weak excitation occurred in response to mechanosensory stimuli to cerci. In contrast, interneurons with dendrites mainly in the antennal lobe projection sites send axon terminals to the middle to outer layers of the calyces. These were excited by various olfactory stimuli and mechanosensory stimuli to the antenna. These results suggest that there is general modality-specific terminal segregation in the MB calyces and that this is an early event in insect evolution. Possible postsynaptic and presynaptic elements of these neurons are discussed. (C) 2011 Elsevier Ltd. All rights reserved.
  • Hans-Joachim Pflueger, Laurence H. Field, Hiroshi Nishino, Margaret J. Currie
    JOURNAL OF INSECT PHYSIOLOGY 57 10 1420 - 1430 2011年10月 [査読有り][通常論文]
     
    Wetas are ancient Gondwanan orthopterans (Anostostomatidae) with many species endemic to New Zealand. Like all Orthoptera they possess efferent neuromodulatory dorsal unpaired median (DUM) neurons, with bilaterally symmetrical axons, that are important components of motor networks. These neurons produce overshooting action potentials and are easily stimulated by a variety of external mechanosensory stimuli delivered to the body and appendages. In particular, stimulation of the antennae, mouth parts, tarsi and femora of the legs, abdomen, cerci and ovipositor is very effective in activating DUM neurons in the metathoracic ganglion of wetas. In addition, looming visual stimuli or light on-, light off-stimuli excite many metathoracic DUM neurons. These DUM sensory reflex pathways remain viable after the prothoracic to subesophageal connective is cut, whereas in locusts such reflex pathways are interrupted by the ablation. This suggests that, in wetas, sensory reflex pathways for DUM activation are organized in a less centralized fashion than in locusts, and may therefore reflect a plesiomorphic evolutionary state in the weta. In addition, many weta DUM neurons exhibit slow rhythmic bursting which also persists following the connective ablation. (C) 2011 Elsevier Ltd. All rights reserved.
  • Hiroshi Nishino, Masazumi Iwasaki, Makoto Mizunami
    CHEMICAL SENSES 36 3 261 - 270 2011年03月 [査読有り][通常論文]
     
    Many animals depend on pheromone communication for successful mating. Sex pheromone in insects is usually released by females to attract males. In American cockroaches, the largest glomerulus (B-glomerulus) in the male antennal lobe (first-order olfactory center) processes the major component of sex pheromone. Using intracellular recordings combined with fine neuroanatomical techniques, we provide evidence that the female homolog of the male B-glomerulus also acts as a sex pheromone-specific detector. Whereas ordinary glomeruli that process normal environmental odors are innervated by single projection neurons (PNs), the B-glomerulus in both sexes is innervated by multiple PNs, one of which possesses a thicker axon, termed here B-PN. Both soma size and axon diameter were smaller on B-PNs from females compared with B-PNs from males. The female B-PNs also produce fewer terminal arborizations in the protocerebrum than male B-PNs. Termination fields in the lateral protocerebrum of the female B-PN are mostly segregated from those formed by other uniglomerular PNs innervating ordinary glomeruli. Female B-PN activity was greatest in response to sex pheromone but lower than that in the male B-PN. This specific detection system suggests that sex pheromone affects the behavior and/or endocrine system of female cockroaches.
  • Hidehiro Watanabe, Chihiro Sato Matsumoto, Hiroshi Nishino, Makoto Mizunami
    NEUROBIOLOGY OF LEARNING AND MEMORY 95 1 1 - 13 2011年01月 [査読有り][通常論文]
     
    In insects, cholinergic neurons are thought to transmit olfactory conditioned stimulus (CS) to the sites for associating the CS with unconditioned stimulus (US), but the types of acetylcholine (ACh) receptor used by neurons participating in the association have not been determined. In cockroaches, a type of nicotinic ACh receptor specifically antagonized by mecamylamine (MEC) has been characterized. Here we investigated the roles of neurons possessing MEC-sensitive ACh receptors (MEC-sensitive neurons) in olfactory conditioning of salivation, monitored by changes in activities of salivary neurons, in cockroaches. Local and bilateral microinjection of MEC into each of the three olfactory centers, antennal lobes, calyces of the mushroom bodies and lateral protocerebra, impaired olfactory responses of salivary neurons, indicating that MEC-sensitive neurons in all olfactory centers participate in pathways mediating olfactory responses of salivary neurons. Conditioning of olfactory CS with sucrose US was impaired by injection of MEC into the antennal lobes or calyces, i.e., conditioned responses were absent even after recovery from MEC injection, suggesting that the CS-US association occurs in MEC-sensitive neurons in calyces (most probably Kenyon cells) or in neurons in downstream pathways. In contrast, conditioned responses appeared after recovery from MEC injection into the lateral protocerebra, suggesting that MEC-sensitive neurons in the lateral protocerebra are downstream of the association sites. Since lateral protocerebra are major termination areas of mushroom body efferent neurons, we suggest that input synapses of MEC-sensitive Kenyon cells, or their output synapses upon mushroom body efferent neurons, are the sites for CS-US association for conditioning of salivation. (C) 2010 Elsevier Inc. All rights reserved.
  • Hidehiro Watanabe, Hiroshi Nishino, Michiko Nishikawa, Makoto Mizunami, Fumio Yokohari
    JOURNAL OF COMPARATIVE NEUROLOGY 518 19 3907 - 3930 2010年10月 [査読有り][通常論文]
     
    Glomeruli are structural and functional units in the primary olfactory center in vertebrates and insects. In the cockroach Periplaneta americana, axons of different types of sensory neurons housed in sensilla on antennae form dorsal and ventral antennal nerves and then project to a number of glomeruli. In this study, we identified all antennal lobe (AL) glomeruli based on detailed innervation patterns of sensory tracts in addition to the shape, size, and locations in the cockroach. The number of glomeruli is similar to 205, and no sex-specific difference is observed. Anterograde dye injections into the antennal nerves revealed that axons supplying the AL are divided into 10 sensory tracts (T1-T10). Each of T1-T3 innervates small, oval glomeruli in the anteroventral region of the AL, with sensory afferents invading each glomerulus from multiple directions, whereas each of T4-T10 innervates large glomeruli with various shapes in the posterodorsal region, with a bundle of sensory afferents invading each glomerulus from one direction. The topographic branching patterns of all these tracts are conserved among individuals. Sensory afferents in a sub-tract of T10 had axon terminals in the dorsal margin of the AL and the protocerebrum, where they form numerous small glomerular structures. Sensory nerve branching pattern should reflect developmental processes to determine spatial arrangement of glomeruli, and thus the complete map of glomeruli based on sensory nerve branching pattern should provide a basis for studying the functional significance of spatial arrangement of glomeruli and its developmental basis. J. Comp. Neurol. 518:3907-3930, 2010. (C) 2010 Wiley-Liss, Inc.
  • Aki Nakanishi, Hiroshi Nishino, Hidehiro Watanabe, Fumio Yokohari, Michiko Nishikawa
    JOURNAL OF COMPARATIVE NEUROLOGY 518 12 2186 - 2201 2010年06月 [査読有り][通常論文]
     
    Ants have well-developed chemosensory systems for social lives. The goal of our study is to understand the functional organization of the ant chemosensory system based on caste- and sex-specific differences. Here we describe the common and sex-specific glomerular organizations in the primary olfactory center, the antennal lobe of the carpenter ant Camponotus japonicus. Differential labeling of the two antennal nerves revealed distinct glomerular clusters innervated by seven sensory tracts (T1-T7 from ventral to dorsal) in the antennal lobe. T7 innervated 10 glomeruli, nine of which received thick axon terminals almost exclusively from the ventral antennal nerve. Coelocapitular (hygro-/thermoreceptive), coeloconic (thermoreceptive), and ampullaceal (CO(2)-receptive) sensilla, closely appositioned in the flagellum, housed one or three large sensory neurons supplying thick axons exclusively to the ventral antennal nerve. These axons, therefore, were thought to project into T7 glomeruli in all three castes. Workers and virgin females had about 140 T6 glomeruli, whereas males completely lacked these glomeruli. Female-specific basiconic sensilla (cuticular hydrocarbon-receptive) contained over 130 sensory neurons and were completely lacking in males' antennae. These sensory neurons may project into T6 glomeruli in the antennal lobe of workers and virgin females. Serotonin-immunopositive neurons innervated T1-T5 and T7 glomeruli but not T6 glomeruli in workers and virgin females. Because males had no equivalents to T6 glomeruli, serotonin-immunopositive neurons appeared to innervate all glomeruli in the male's antennal lobe. T6 glomeruli in workers and virgin females are therefore female-specific and may have functions related to female-specific tasks in the colony rather than sexual behaviors. J. Comp. Neurol. 518:2186-2201, 2010. (C) 2010 Wiley-Liss, Inc.
  • Hiroshi Nishino, Atsushi Yoritsune, Makoto Mizunami
    NEUROSCIENCE LETTERS 469 1 60 - 64 2010年01月 [査読有り][通常論文]
     
    In most insects, sex pheromone is processed by an enlarged glomerular complex (macroglomerular complex, MGC) in the male antennal lobe (first-order olfactory center). The MGC of the American cockroach consists of two closely located A- and B-glomeruli which are responsible for processing the major sex pheromone components, periplanone-A and -B, respectively. Using anterograde dye injection, we investigated sexual dimorphism in sensory afferents and interneuron. The A- and B-glomeruli exist in the first larval instar of both sexes. The female MGC homolog grows at a relatively constant rate (1.2-1.8-fold growth per molt) throughout development, whereas the male MGC shows a period of accelerated growth between the fifth and ninth instars, where volume can be more than double in a single molt. These different growth patterns resulted in a 1:30 ratio in glomerular complex volumes of adult females versus males. In the female MGC homolog, afferents originating from the dorsal and ventral antennal surfaces were biased toward anterior and posterior regions, and segregation of these afferents was less clear compared to the adult male. The staining of interneurons projecting to the protocerebrum revealed that projection patterns characteristic of sex pheromone processing appear in the late eighth instar in males, while possibly homologous projections in the female were far fewer in number. These results suggest that the glomerular complexes in pre-eighth larval males, and probably females, are not differentiated for specific detection of sex pheromone. Male-specific projections for sex pheromone detection may be formed by modification of pre-existing neural circuitry. (C) 2009 Elsevier Ireland Ltd. All rights reserved.
  • Makoto Mizunami, Nobuhiro Yamagata, Hiroshi Nishino
    FRONTIERS IN BEHAVIORAL NEUROSCIENCE 4 28  2010年 [査読有り][通常論文]
     
    Social insects exhibit sophisticated communication by means of pheromones, one example of which is the use of alarm pheromones to alert nestmates for colony defense. We review recent advances in the understanding of the processing of alarm pheromone information in the ant brain. We found that information about formic acid and n-undecane, alarm pheromone components, is processed in a set of specific glomeruli in the antennal lobe of the ant Camponotus obscuripes. Alarm pheromone information is then transmitted, via projection neurons (PNs), to the lateral horn and the calyces of the mushroom body of the protocerebrum. In the lateral horn, we found a specific area where terminal boutons of alarm pheromone-sensitive PNs are more densely distributed than in the rest of the lateral horn. Some neurons in the protocerebrum responded specifically to formic acid or n-undecane and they may participate in the control of behavioral responses to each pheromone component. Other neurons, especially those originating from the mushroom body lobe, responded also to non-pheromonal odors and may play roles in integration of pheromonal and non-pheromonal signals. We found that a class of neurons receive inputs in the lateral horn and the mushroom body lobe and terminate in a variety of premotor areas. These neurons may participate in the control of aggressive behavior, which is sensitized by alarm pheromones and is triggered by non-pheromonal sensory stimuli associated with a potential enemy. We propose that the alarm pheromone processing system has evolved by differentiation of a part of general odor processing system.
  • Aki Nakanishi, Hiroshi Nishino, Hidehiro Watanabe, Fumio Yokohari, Michiko Nishikawa
    CELL AND TISSUE RESEARCH 338 1 79 - 97 2009年10月 [査読有り][通常論文]
     
    The antennae are a critically important component of the ant's highly elaborated chemical communication systems. However, our understanding of the organization of the sensory systems on the antennae of ants, from peripheral receptors to central and output systems, is poorly understood. Consequently, we have used scanning electron and confocal laser microscopy to create virtually complete maps of the structure, numbers of sensory neurons, and distribution patterns of all types of external sensilla on the antennal flagellum of all types of colony members of the carpenter ant Camponotus japonicus. Based on the outer cuticular structures, the sensilla have been classified into seven types: coelocapitular, coeloconic, ampullaceal, basiconic, trichoid-I, trichoid-II, and chaetic sensilla. Retrograde staining of antennal nerves has enabled us to count the number of sensory neurons housed in the different types of sensilla: three in a coelocapitular sensillum, three in a coeloconic sensillum, one in an ampullaceal sensillum, over 130 in a basiconic sensillum, 50-60 in a trichoid-I sensillum, and 8-9 in a trichoid-II sensillum. The basiconic sensilla, which are cuticular hydrocarbon-receptive in the ant, are present in workers and unmated queens but absent in males. Coelocapitular sensilla (putatively hygro- and thermoreceptive) have been newly identified in this study. Coelocapitular, coeloconic, and ampullaceal sensilla form clusters and show biased distributions on flagellar segments of antennae in all colony members. The total numbers of sensilla per flagellum are about 9000 in unmated queens, 7500 in workers, and 6000 in males. This is the first report presenting comprehensive sensillar maps of antennae in ants.
  • Yoshihiro Nakatani, Yukihisa Matsumoto, Yasuhiro Mori, Daisuke Hirashima, Hiroshi Nishino, Kentaro Arikawa, Makoto Mizunami
    NEUROBIOLOGY OF LEARNING AND MEMORY 92 3 370 - 380 2009年10月 [査読有り][通常論文]
     
    One of the most extensively debated topics in educational psychology is whether punishment or reward is more effective for producing short-term and long-term behavioral changes, and it has been proposed that the effect of punishment is less durable than the effect of reward. However, no conclusive evidence to support this proposal has been obtained in any animals. We recently found that punishment memory decayed much faster than reward memory in olfactory learning and visual pattern learning in crickets. We also found that neurotransmitters conveying punishment and reward signals differ in crickets: dopaminergic and octopaminergic neurons play critical roles in conveying punishment and reward signals, respectively. In this study, we investigated whether these features are general features of cricket learning or are specific to olfactory and visual pattern learning. We found that crickets have the capability of color learning and that their color learning has the same features. Based on our findings in crickets and those reported in other species of insects, we conclude that these two features are conserved in many forms of insect learning. In mammals, aminergic neurons are known to convey reward and punishment signals in learning of a variety of sensory stimuli. We propose that the faster decay of punishment memory than reward memory observed in insects and humans reflects different cellular and biochemical processes after activation of receptors for amines conveying punishment and reward signals. The possible adaptive significance of relatively limited durability of punishment memory is proposed. (C) 2009 Elsevier Inc. All rights reserved.
  • Hiroshi Nishino, Michiko Nishikawa, Makoto Mizunami, Fumio Yokohari
    JOURNAL OF COMPARATIVE NEUROLOGY 515 2 161 - 180 2009年07月 [査読有り][通常論文]
     
    In the primary olfactory center of animals, glomeruli are the relay stations where sensory neurons expressing cognate odorant receptors converge onto interneurons. In cockroaches, moths, and honeybees, sensory afferents from sensilla on the anterodorsal surface and the posteroventral surface of the flagellum form two nerves of almost equal thicknesses. In this study, double labeling of the two nerves, or proximal/distal regions of the nerves, with fluorescent dyes was used to investigate topographic organization of sensory afferents in the honeybee. The sensory neurons of ampullaceal sensilla responsive to CO(2), coelocapitular sensilla responsive to hygrosensory, and thermosensory stimuli and coeloconic sensilla of unknown function were characterized with large somata and supplied thick axons exclusively to the ventral nerve. Correspondingly, all glomeruli innervated by sensory tract (T) 4 received thick axonal processes exclusively from the ventral nerve. Almost all T1-3 glomeruli received a similar number of sensory afferents from the two nerves. In the macroglomerular complexes of the drone, termination fields of afferents from the two nerves almost completely overlapped; this differs from moths and cockroaches, which show heterogeneous terminations in the glomerular complex. In T1-3 glomeruli, sensory neurons originating from more distal flagellar segments tended to terminate within the inner regions of the cortical layer. These results suggest that some degree of somatotopic organization of sensory afferents exist in T1-3 glomeruli, and part of T4 glomeruli serve for processing of hygro- and thermosensory signals. J. Comp. Neurol. 515: 161-180, 2009. (C) 2009 Wiley-Liss, Inc.
  • 西野浩史, 頼経篤史, 岩崎正純
    日本動物学会大会予稿集 80th (Web) 3 219 - 224 2009年 [査読有り][通常論文]
     
    In many insect species, sex pheromone is processed by specific, enlarged glomeruli in the antennal lobes of males. In the male American cockroach, two closely located glomeruli (A and B) are responsible for processing the major pheromone components (periplanone-A and -B, respectively), and these collectively form the macroglomerular complex. Afferents originating from the dorsal and ventral surfaces of the antenna tend to project to the anterior and posterior regions of the macroglomerular complex via the dorsal and ventral antennal nerves, respectively. This topographic segregation of afferents is seen only in the macroglomerular complex, and not in other glomeruli that process normal environmental odors. Using differential, anterograde dye injection into the two antennal sensory nerves, we show that the macroglomerular complex is not formed by fusion of several glomeruli, as suggested in previous studies. but that the precursors of the A- and B-glomeruli already exist in the first larval instar. The volume of afferents in the macroglomerular complex precursor increases nearly exponentially with molting times. 430-fold from the first instar to the adult. The A- and B-glomeruli both undergo continuous growth during postembryonic development, but peak growth rates occur in different larval stages. The growth rate of the B-glomerulus peaked in the mid-developmental stage then declined, while growth of A-glomerulus was maintained at low level in early- to mid-developmental stages but increased greatly in later stages. These results suggest perception of sex pheromone occurs in early instars, and that PA and PB have distinct roles in different developmental stages. (c) 2009 Elsevier Ireland Ltd. All rights reserved.
  • Hidehiro Watanabe, Chihiro Sato, Tomokazu Kuramochi, Hiroshi Nishino, Makoto Mizunami
    NEUROBIOLOGY OF LEARNING AND MEMORY 90 1 245 - 254 2008年07月 [査読有り][通常論文]
     
    Classical conditioning of olfactory conditioning stimulus (CS) with gustatory unconditioned stimulus (US) in insects has been used as a pertinent model for elucidation of neural mechanisms underlying learning and memory. However, a conditioning system in which stable intracellular recordings from brain neurons are feasibly obtained while monitoring the conditioning effect has remained to be established. Recently, we found classical conditioning of salivation in cockroaches Periplaneta americana, in which an odor was associated with sucrose solution applied to the mouth, and this conditioning could be monitored by activities of salivary neurons. Application of gustatory US to the mouth, however, leads to feeding movement accompanying a movement of the brain that prevents stable recordings from brain neurons. Here we investigated whether a gustatory stimulus presented to an antenna could serve as an effective US for producing salivary conditioning. Presentation of sucrose or sodium chloride solution to an antenna induced salivation and also increased activities of salivary neurons. A single pairing trial of an odor with antennal presentation of sucrose or sodium chloride solution produced conditioning of salivation or of activities of salivary neurons. Five pairing trials led to a conditioning effect that lasted for one day. Water or tactile stimulus presented to an antenna was not effective for producing conditioning. The results demonstrate that gustatory US presented to an antenna is as effective as that presented to the mouth for producing salivary conditioning. This conditioning system provides a useful model for studying the neural basis of learning at the level of singly identifiable neurons. (C) 2008 Elsevier Inc. All rights reserved.
  • Michiko Nishikawa, Hiroshi Nishino, Yuko Misaka, Maiko Kubota, Eriko Tsuji, Yuji Satoji, Mamiko Ozaki, Fumio Yokohari
    ZOOLOGICAL SCIENCE 25 2 195 - 204 2008年02月 [査読有り][通常論文]
     
    The carpenter ant, a social hymenopteran, has a highly elaborated antennal chemosensory system that is used for chemical communication in social life. The glomeruli in the antennal lobe are the first relay stations where sensory neurons synapse onto interneurons. The system is functionally and structurally similar to the olfactory bulbs of vertebrates. Using three-dimensional reconstruction of glomeruli and subsequent morphometric analyses, we found sexual dimorphism of the antennal lobe glomeruli in carpenter ants, Camponotus japonicus. Female workers and unmated queens had about 430 glomeruli, the highest number reported so far in ants. Males had a sexually dimorphic macroglomerulus and about 215 ordinary glomeruli. This appeared to result from a greatly reduced number of glomeruli in the postero-medial region of the antennal lobe compared with that in females. On the other hand, sexually isomorphic glomeruli were identifiable in the dorsal region of the antennal lobe. For example, large, uniquely shaped glomeruli located at the dorso-central margin of the antennal lobe were detected in all society members. The great sexual dimorphism seen in the ordinary glomeruli of the antennal lobe may reflect gender-specific tasks in chemical communications rather than different reproductive roles.
  • Nobuhiro Yamagata, Hiroshi Nishino, Makoto Mizunami
    JOURNAL OF COMPARATIVE NEUROLOGY 505 4 424 - 442 2007年12月 [査読有り][通常論文]
     
    Social insects like ants exhibit sophisticated communication by means of pheromones, one example of which is the use of alarm pheromones to alert nestmates for colony defense. 14 In the ant Camponotus obscuripes, we have reported that information about formic acid and n-undecane, alarm pheromone components, is processed in a set of specific glomeruli in the antennal lobe (primary olfactory center). Alarm pheromone signals are then transmitted, mainly via uniglomerular projection neurons (uni-PNs), to the protocerebrum (PR), where sensory signals are integrated to form motor commands for behavioral responses. In this study, we physiologically and morphologically characterized 63 alarm pheromone-sensitive PR neurons in ants by using intracellular recording and staining techniques. Most of the pheromone-sensitive PR neurons had dendrites in the mushroom body (MB), the lateral horn, or the medial PR. Some neurons with dendrites in these areas responded specifically to formic acid or n-undecane and may participate in the control of specific behavioral responses to each pheromone component. Other neurons responded also to non-pheromonal odors, in contrast to uni-PNs, most of which responded specifically to alarm pheromones. Responses to nonpheromonal odors were most prominent in efferent neurons of the MB lobe, suggesting that they may participate in integration of pheromonal and non-pheromonal information. We found a class of PR neurons that receives input in all of these pheromone-processing areas and terminates in a variety of premotor areas. These neurons may participate in the control of pheromone-sensitized aggressive behavior, which is triggered by non-pheromonal sensory stimuli associated with a potential enemy.
  • Hiroshi Nishino, Makoto Mizunami
    NEUROREPORT 18 17 1765 - 1769 2007年11月 [査読無し][通常論文]
     
    The spatial distribution of chemosensory afferent terminals within glomeruli, with respect to their peripheral origin, was investigated using differential staining of afferents in the cockroach. In all glomeruli, the axon terminals of afferents originating from the more distal regions of the flagellum tended to occur in the more distal regions of the glomeruli, relative to the axonal entry side. Afferent terminals tend to be spatially separated, on the basis of their circumferential origin on the flagellum, in pheromone-receptive glomerular complexes and posterodorsally located large glomeruli; however, they were randomly scattered in anteroventrally located small glomeruli. These results revealed that the location of afferent terminals strongly reflects the three-dimensional position of their olfactory receptor neurons in pheromone-receptive glomeruli, but the relationship is weaker in other glomeruli.
  • Masazumi Iwasaki, Hiroshi Nishino, Antonia Delago, Hitoshi Aonuma
    ZOOLOGICAL SCIENCE 24 9 860 - 868 2007年09月 [査読無し][通常論文]
     
    After a loss against an opponent, the aggressiveness of a male cricket is significantly reduced for up to 30 minutes. This depression of aggressiveness is an important factor in the establishment and maintenance of dominance between individuals. In the present study, we investigated the functional roles of nitric oxide (NO) signaling in the depression of aggressiveness in subordinate male crickets. Pairs of male crickets, pre-injected with various NO-related reagents, were allowed to establish dominant/subordinate relationships in dyadic encounters. Opponents were separated for 15 minutes and then paired again. In second encounters, subordinate crickets pre-injected with PTIO (NO scavenger) showed agonistic behavior towards former dominant opponents. A similar effect was observed in crickets pre-injected with L-NAME (NO synthase inhibitor) or ODQ (soluble guanylate cyclase inhibitor). The effects of the latter two drugs were canceled by co-injection of NOR3 (NO donor) with L-NAME or by co-injection of 8-Br-cGMP (cGMP-analog) with ODQ. Injection of NOR3 alone prolonged the inhibition of agonistic behavior in subordinate crickets from 30 minutes to 3 hours. Our results suggest that the change in agonistic behavior observed in subordinate male crickets is closely linked to NO-mediated cGMP signaling.
  • Hiroyuki Ai, Hiroshi Nishino, Tsunao Itoh
    JOURNAL OF COMPARATIVE NEUROLOGY 502 6 1030 - 1046 2007年06月 [査読無し][通常論文]
     
    Johnston's organ (JO) in insects is a multicellular mechanosensory organ stimulated by movement of the distal part of the antenna. In honeybees JO is thought to be a primary sensor detecting air-particle movements caused by the waggling dance of conspecifics. In this study projection patterns of JO afferents within the brain were investigated. About 720 somata, distributed around the periphery of the second segment of the antenna (pedicel), were divided into three subgroups based on their soma location: an anterior group, a ventral group, and a dorsal group. These groups sent axons to different branches (N2 to N4) diverged from the antennal nerve. Dye injection into individual nerve branches revealed that all three groups of afferents, having fine collaterals in the dorsal lobe, sent axons broadly through tracts T6I, T6II, and T6III to terminate ipsilaterally in the medial posterior protocerebral lobe, the dorsal region of the subesophageal ganglion, and the central posterior protocerebral lobe, respectively. Within these termination fields only axon terminals running in T6I were characterized by thick processes with large varicosities. Differential staining using fluorescent dyes revealed that the axon terminals of the three groups were spatially segregated, especially in T6I, showing some degree of somatotopy. This spatial segregation was not observed in axon terminals running in other tracts. Our results show that projection patterns of JO afferents in the honeybee brain fundamentally resemble those in the dipteran brain. The possible roles of extensive termination fields of JO afferents in parallel processings of mechanosensory signals are discussed.
  • Masazumi Iwasaki, Antonia Delago, Hiroshi Nishino, Hitoshi Aonuma
    ZOOLOGICAL SCIENCE 23 10 863 - 872 2006年10月 [査読無し][通常論文]
     
    Male solitary animals frequently enter aggressive interactions with conspecific individuals to protect their territory or to gain access to females. After an agonistic encounter, the loser (subordinate individual) changes its behaviour from aggression to avoidance. We investigated agonistic interactions between pairs of male crickets to understand how dominance is established and maintained. Two naive males readily entered into agonistic interactions. Fights escalated in a stereotyped manner and were concluded with the establishment of dominance. If individuals were isolated after the first encounter and placed together 15 minutes later, subordinate crickets tended to avoid any further contact with the former dominant opponent. Moreover, subordinate males also avoided unfamiliar dominant and naive opponents. They displayed aggressive behaviour only towards unfamiliar subordinate opponents. This suggests that the subordinate male change their behaviour depending on the dominance status of the opponent. Dominant crickets, in contrast, displayed aggressive behaviour towards familiar as well as unfamiliar opponents. If the interval between the first and second encounter was longer than 30 minutes, the former subordinate male showed aggressive behaviour again. However, if the subordinate cricket was paired with the same opponent three consecutive times within 45 minutes, it avoided the former dominant opponent for up to 6 hours following the third encounter. Our results suggest that the maintenance of dominance in male crickets depends largely on the behavioural change of subordinate individuals. Possible mechanisms to maintain dominance are discussed.
  • Nobuhiro Yamagata, Hiroshi Nishino, Makoto Mizunami
    PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES 273 1598 2219 - 2225 2006年09月 [査読有り][通常論文]
     
    Tremendous evolutional success and the ecological dominance of social insects, including ants, termites and social bees, are due to their efficient social organizations and their underlying communication systems. Functional division into reproductive and sterile castes, cooperation in defending the nest, rearing the young and gathering food are all regulated by communication by means of various kinds of pheromones. No brain structures specifically involved in the processing of non-sexual pheromone have been physiologically identified in any social insects. By use of intracellular recording and staining techniques, we studied responses of projection neurons of the antermal lobe (primary olfactory centre) of ants to alarm pheromone, which plays predominant roles in colony defence. Among 23 alarm pheromone-sensitive projection neurons recorded and stained in this study, eight were uniglomerular projection neurons with dendrites in one glomerulus, a structural unit of the antermal lobe, and the remaining 15 were multiglomerular projection neurons with dendrites in multiple glomeruli. Notably, all alarm pheromone-sensitive uniglomerular projection neurons had dendrites in one of five 'alarm pheromone-sensitive (AS)' glomeruli that form a cluster in the dorsalmost part of the antermal lobe. All alarm pheromone-sensitive multiglomerular projection neurons had dendrites in some of the AS glomeruli as well as in glomeruli in the anterodorsal area of the antermal lobe. The results suggest that components of alarm pheromone are processed in a specific cluster of glomeruli in the antennal lobe of ants.
  • Hiroshi Nishino, Makoto Mizunami
    NEUROREPORT 17 12 1303 - 1307 2006年08月 [査読無し][通常論文]
     
    In cockroach antennae, sensory afferents from sensilla on the anterodorsal surface of the flagellum form the anterior antennal nerve, while afferents from the posteroventral surface form the posterior nerve. Anterograde staining was used to investigate afferent termination profiles in the glomeruli of the antennal lobe. The densities of terminal arborizations from the two nerves differed between glomeruli, with groupings of similar glomeruli evident. Individual glomeruli showed heterogeneous distribution of afferent terminals, with posterior nerve afferent terminals occurring near the nerve/glomeruli interface, and anterior nerve afferent terminals occurring on the opposite side. This study demonstrates, for the first time, a correlation between the distribution of primary afferent terminals in the individual glomeruli, and their origin on the surface of the flagellum.
  • Hiroshi Nishino, Michiko Nishikawa, Fumio Yokohari, Makoto Mizunami
    Journal of Comparative Neurology 493 2 291 - 308 2005年12月12日 [査読無し][通常論文]
     
    The antennae of most insects move actively and detect the physical and chemical composition of objects encountered by using their associated tactile sensors. Positional information is required for these sensory modalities to interpret the physical environment. Although we have a good understanding of antennal olfactory pathways, little is known about the destinations of antennal mechanosensory and contact chemosensory (gustatory) receptor neurons in the central nervous system. The cockroach Periplaneta is equipped with a pair of long, thin antennae, which are covered in bristles. The distal portions of each antenna possess about 6,500 bimodal bristles that house one tactile sensory and one to four contact chemosensory neurons. In this study, we investigated the morphologies of bimodal bristle receptor afferents by staining individual or populations of bristles. Unlike olfactory afferents, which project exclusively into the glomeruli in the ventral region of the deutocerebrum, both the presumptive mechanosensory and the contact chemosensory afferents projected into the posterior dorsal region of the deutocerebrum and the anterior region of the subesophageal ganglion. Each afferent showed multilayered segmentation and spatial occupation reflecting its three-dimensional position in the periphery. Presumptive contact chemosensory afferents, characterized by their thin axons and unique branching pattern, occupied more medioventral positions compared with the presumptive tactile afferents. Furthermore, projection fields of presumptive contact chemosensory afferents from single sensilla tended to be segregated from each other. These observations suggest that touch and taste positional information from the antenna is precisely represented in primary centers in a modality-specific manner. © 2005 Wiley-Liss, Inc.
  • H Nishino
    JOURNAL OF EXPERIMENTAL BIOLOGY 207 22 3899 - 3915 2004年10月 [査読無し][通常論文]
     
    The cricket Gryllus bimaculatus displays a sudden rigid immobility (thanatosis) when voluntary leg movements are forcibly restrained. The tibial joints in all legs are stiffly immobilized for several minutes. The flexed-leg posture typical of thanatosis is maintained by the flexor tibiae muscle. To characterize thanatosis at the motor output level, the mechanical and physiological properties of the metathoracic tibia muscle were investigated. The accessory flexor muscle, especially well-developed in the cricket, acts to stably maintain the tibial flexion driven by the main flexor muscle. Extracellular recordings from the flexor muscle of tethered crickets revealed that activity of intermediate- and fast-excitatory units was almost completely suppressed, while slow-excitatory units persisted in firing tonically during thanatosis. The firing rate of slow-excitatory units progressively increased as the tibia flexed, but remained less than the firing rate seen in the quiescent state. Common inhibitory motor neurones that fire sporadically in the quiescent state were suppressed during thanatosis, especially in the beginning, and showed a large excitation immediately after arousal. These findings suggest that the entire motor neuronal pool is held under active suppression during thanatosis, and that flexor muscle rigidity is maintained by a weak discharge of the slow exciters together with suppression of the inhibitors.
  • H Nishino, LH Field
    JOURNAL OF COMPARATIVE NEUROLOGY 464 3 327 - 342 2003年09月 [査読無し][通常論文]
     
    Most ensiferan insects possess sets of highly specialized chordotonal organs in the proximal tibiae to detect conspecific auditory/vibratory signals or approach of predators. To date, most auditory/vibratory afferents have been classified according to their physiological properties and axonal projection morphology, but not to somatotopic origins. Hence, the functional specialization of identified receptor cells in the tibial organs remains uncertain. To address this question from an anatomical aspect, we investigated the structure of the weta, Hemideina femorata, tibial organs (the most elaborated tibial chordotonal organs among ensiferans) and their central projections by staining small numbers of receptor afferents from identified tibial organs. These organs comprise the "complex tibial organ," including the subgenual organ (primary vibration detector) and its posterior complement, the accessory organ, and the crista acustica (primary auditory organ) and its proximal complement, the intermediate organ. Unlike reports of a membranous organ structure for homologs in other ensiferans, weta tibial organs contain receptor cells embedded in thick solid masses. Primary afferents project ipsilaterally to the medial ventral association center of thoracic ganglia, where axon terminals are arrayed topographically in different areas specific to each organ, except for almost complete overlap of afferents originating from the distal part of the crista acustica and from the intermediate organ. In contrast to somatotopic reflection of sensilla position on limbs, as known for mechanoreceptor hairs, the somatotopic projection map of the insect ear reveals topographic association with acoustic tracheae or tibial cuticular attachment sites, which in turn must reflect determinants of response sensitivity (e.g., frequency or threshold). (C) 2003 Wiley-Liss, Inc.
  • H Nishino
    JOURNAL OF COMPARATIVE NEUROLOGY 464 3 312 - 326 2003年09月 [査読無し][通常論文]
     
    The femoral chordotonal organ (FCO) in orthopteran insects comprises several hundred sensory neurons, making it one of the most complex insect proprioceptors. The sensory neurons are suspended from the proximal femur, connecting distally to ligaments and to a needle-like apodeme extending from the proximal tibia. They monitor the position and movement of the tibia. To address how this complexity depends on evolutionary status and function, the morphology of the FCO neurons in the primitive orthopteran Hemideina femorata was investigated by staining small populations of identified afferents. As in crickets, the FCOs in all legs of the weta comprise partly fused ventral and dorsal scoloparia, with the former containing two groups of somata, the ventral group (VG) and the dorsal group (DG). However, the dendrites of the DG insert into thin connective tissue attached to the ventral side of the dorsal ligament, forming a "third scoloparium." The VG afferents terminate mainly in the motor association neuropils, whereas afferents from the dorsal scoloparium neurons terminate exclusively in the vibratory neuropil as do the afferents from the sub-genual organ, a substrate vibration detector. Several afferents originating in the DG have extensive terminations in the motor association-, vibratory-, and auditory-processing neuropils, indicating lesser functional specialization than in the other groups. The evolutionary development of the FCO is discussed from a comparative viewpoint. (C) 2003 Wiley-Liss, Inc.
  • H Nishino
    ZOOLOGICAL SCIENCE 20 6 697 - 707 2003年06月 [査読無し][通常論文]
     
    To elucidate neural mechanisms underlying walking and jumping in insects, motor neurons supplying femoral muscles have been identified mainly in locusts and katydids, but not in crickets. In this study, the motor innervation patterns of the metathoracic flexor and extensor tibiae muscles in the cricket, Gryllus bimaculatus were investigated by differential back-fills and nerve recordings. Whereas the extensor tibiae muscle has an innervation pattern similar to that of other orthopterans, the flexor has an innervation unique to this species. The main body of the flexor muscle is divided into the proximal, middle and distal regions, which receive morphologically unique terminations from almost non-overlapping sets of motor neurons. The proximal region is innervated by about 12 moderate-sized excitatory motor neurons and two inhibitory neurons while the middle and distal regions are innervated by three and four large excitatory motor neurons, respectively. The most-distally located accessory flexor muscle, inserting on a common flexor apodeme with the main muscle, is innervated by at least four small excitatory (slow-type) and two common inhibitory motor neurons. The two excitatory and two inhibitory motor neurons that innervate the accessory flexor muscle also innervate the proximal bundles of the main flexor muscle. This suggests that the most proximal and distal parts of the flexor muscle participate synergistically in fine motor control while the rest participates in powerful drive of tibial flexion movement.
  • H Nishino, S Yamashita, Y Yamazaki, M Nishikawa, F Yokohari, M Mizunami
    JOURNAL OF COMPARATIVE NEUROLOGY 455 1 40 - 55 2003年01月 [査読無し][通常論文]
     
    Most insects are equipped with specialized thermo- and hygroreceptors to locate a permissible range of ambient temperature and distant water sources, respectively. In the cockroach, Periplaneta americana, cold, moist, and dry receptor cells in the antennae send axons to particular sets of two or three glomeruli in the dorsocentral part of the antennal lobe (primary olfactory center), designated DC1-3 glomeruli. However, it is not known how thermo- and hygrosensory signals from these glomeruli are represented in higher-order centers, the protocerebrum, in any insect species. With the use of intracellular recording and staining techniques, we identified a new class of interneurons with dendrites almost exclusively in the DC1, DC2, or DC3 glomeruli and axons projecting to the protocerebrum in the cockroach. Remarkably, terminals of all these projection neurons (PNs) covered almost identical areas in the lateral protocerebrum (LP), although their termination areas outside the LP differed from neuron to neuron. The termination areas within the LP were distinct from, but close to, those of uniglomerular and macroglomerular PNs that transmitted signals concerning general odors and female sex pheromones, respectively. PNs originating from DC1, DC2, and DC3 glomeruli exhibited excitatory responses to cold, moist, and dry stimuli, respectively, probably due to excitatory synaptic input from cold, moist, and dry receptor cells, respectively, whereas their responses were often modulated by olfactory stimuli. These findings suggested that dorsocentral PNs participate in neural pathways that lead to behavioral responses to temperature or humidity changes. (C) 2002 Wiley-Liss, Inc.
  • H Nishino
    CELL AND TISSUE RESEARCH 299 1 145 - 157 2000年01月 [査読有り][通常論文]
     
    Central projections of the femoral chordotonal organ (FCO) neurons in the cricket Gryllus bimaculatus were investigated by selectively staining small numbers of axons. The FCOs in all legs consist of partly fused ventral and dorsal scoloparia in the proximal femur. The ventral scoloparium neurons can be reliably divided into two groups: the ventral group neurons (VG), which are arranged in a sequentially smaller manner distally, and dorsal group neurons (DG), which simply aggregate in the proximal region near the dorsal scoloparium. All axons of the FCO projected to the ipsilateral half of the respective thoracic ganglion. The VG axons possessed dorso-lateral branches in the motor association neuropile and antero-ventral branches dorso-lateral to the anterior ventral association centre. However, the more proximally the somata were situated, the more medially the main neurites terminated. The DG axons showed some variations: some axons of the distally located neurons possessed dorso-lateral branches and terminated on the boundary region of the mVAC, while the other axons terminated exclusively in the medial ventral association centre (mVAC), including the ventral part, which receives auditory sensory neuron projections. All axons of the dorsal scoloparium neurons projected exclusively into the dorsal part of the mVAC; however, the ventrally located neurons projected more ventrally than did the dorsally located neurons. The above characteristics were nearly identical in the pro- and metathoracic FCOs. These results suggest that the cricket FCO axons are roughly organized in a somatotopic map and are broadly differentiated in their function.
  • H Nishino, M Sakai, LH Field
    JOURNAL OF COMPARATIVE PHYSIOLOGY A-SENSORY NEURAL AND BEHAVIORAL PHYSIOLOGY 185 2 143 - 155 1999年08月 [査読有り][通常論文]
     
    The cricket Gryllus bimaculatus displayed freezing (thanatosis) after struggling while the femorotibial joints of the walking legs were forcibly restrained. Myographic recording indicated that strong contraction of the flexor tibia muscle "leg flexion response" occurred under this restrained condition. During thanatosis, when the femoro-tibial joint was passively displaced and held for several seconds, it maintained its new position (catalepsy). Only discharge of the slow flexor units was mechanically indispensable for maintaining thanatosis and catalepsy. Differing roles of identified neuron subgroups of the femoral chordotonal organ were elucidated using this behavioral substrate. Ablation of the dorsal group neurons in the ventral scoloparium strengthened the leg flexion response and the normal resistance reflex, while ablation of the ventral group weakened both motor outputs. Ablation of the dorsal scoloparium neurons, or other main sensory nerves caused no detectable deficiency in femoro-tibial joint control. These results imply that both modes of flexor muscle activation promoted by the ventral group neurons are normally held under inhibitory control by the dorsal group. It is hypothesized that this antagonistic function causes immobilization of the femoro-tibial joint in a wide range of angles in thanatosis and catalepsy.
  • H Nishino, M Mizunami
    NEUROSCIENCE LETTERS 246 1 57 - 60 1998年04月 [査読有り][通常論文]
     
    The mushroom body (MB) of the insect brain is critical to associative memory formation. Intrinsic neurons within the MB (called Kenyon cells, KCs) receive sensory signals from input neurons in the calyces. The calyces of the cockroach MB receive branches of four giant neurons (calycal giants, CGs) which exhibit gamma-aminobutyric acid (GABA)-like immunoreactivity. Here we examined the CGs by intracellular recording and staining. The CGs have dendritic arborizations in the lateral horn (lateral protocerebral lobe) and the neuropil anterior to the alpha and beta loses (output neuropils of the MB); their terminal arborizations cover the entire calyces. The CGs exhibit a spontaneous and rhythmic burst of spikes, which are suppressed by olfactory, visual, tactile or air current stimulation. The CGs may facilitate, by disinhibition, the acquisition of sensory signals by the KCs when the insect is aroused by sensory stimuli. (C) 1998 Elsevier Science ireland Ltd.
  • M Nishikawa, H Nishino, M Mizunami, F Yokohari
    NEUROSCIENCE LETTERS 245 1 33 - 36 1998年03月 [査読有り][通常論文]
     
    Input neurons (INs) in the calyces of the mushroom bodies (MBs) of the cockroach brain were examined by single- or multiple-staining with cobalt lysine and by Golgi impregnation. Olfactory INs had axon terminals with tuft-like, button-like or spiny-blebbed arbors in specific concentric zones in calycal neuropil. INs which responded to light stimulation had thick brush-like arbors along with axonal branches extending radially along the inner layer of calycal neuropil. Some of multiglomerular INs and two types of protocerebral INs extended blebbed axonal branches to the outer surface layer of calycal neuropil or thick bush-like axonal branches with many varicosities to entire calycal neuropil. The distribution patterns of dendrites and axon terminals of INs in the calyces suggest the existence of functional subdivisions in calycal neuropil. (C) 1998 Elsevier Science Ireland Ltd.
  • H Nishino, M Sakai
    JOURNAL OF EXPERIMENTAL BIOLOGY 200 20 2583 - 2595 1997年10月 [査読有り][通常論文]
     
    The arrangement of neuronal somata and their displacement during joint flexion together with the central projection of the pro- and metathoracic femoral chordotonal organs (FCOs) in the cricket were investigated, The FCO consists of the partially fused ventral and dorsal scoloparia in the proximal femur, The ventrally located neurones (the ventral group) form chainlike rows in which somata became sequentially smaller distally and project their axons ipsilaterally to the dorsolateral regions, giving off abundant branches and terminating in the region between the dorsal intermediate tract and the ventral intermediate tract in the thoracic hemiganglion, The dorsal scoloparium, composed of small, simply aggregated neurones, projects exclusively to the medioventral association centre (mVAC), which is known to be an auditory neuropile, In addition, another neural cluster (the dorsal group) was found in the proximo-dorsal region of the ventral scoloparium, This was composed of simply aggregated neurones with axons giving off sparse branches dorso-laterally and terminating in the peripheral region inside the mVAC. The somata of these three groups were displaced distally by flexion of the femoro-tibial joint: the ventral group showed the greatest displacement, with the degree of movement depending upon soma location, while the dorsal group and dorsal scoloparium neurones were hardly displaced, possibly because of their strong connection with the cuticle, These properties were similar in both the prothoracic FCO and the metathoracic FCO, Taken together, the above points suggest that there is greater functional differentiation of the FCO than was previously thought.
  • H Nishino, M Sakai
    JOURNAL OF COMPARATIVE PHYSIOLOGY A-SENSORY NEURAL AND BEHAVIORAL PHYSIOLOGY 179 5 613 - 624 1996年11月 [査読有り][通常論文]
     
    We have found that the cricket Gryllus bimaculatus shows an immobile posture, so-called thanatosis. Thanatosis was reflexly elicited by gently holding the forelegs and pronotum of the cricket. During thanatosis, the respiration rate decreased markedly while the heart rate doubled compared with the resting state. Animals in the state of extreme rigidity were unresponsive to the external disturbances but easily aroused by mechanical stimulation such as prodding. The immobile posture usually persisted for 2-4 min, but occasionally for more than 20 min, and then suddenly ended. Catalepsy was induced during thanatosis when a leg was passively forced to the extended position. For elicitation of the flexion reflex, either campaniform sensilla and femoral chordotonal organs (FCOs) in the forelegs, and spine-like sensilla on the pronotum were necessary. Among these receptors, however, only the FCOs were involved in inducing the immobile state. Centrally, the brain was indispensable for thanatosis to be maintained. In semi-natural conditions the thanatotic state did occur spontaneously while the cricket struggled to get into a small crevice according to the nature of this species. This sudden immobilization could help the cricket get out of danger of predators like reptiles and amphibians in the natural habitat.

書籍

  • 動物学の百科事典
    西野 浩史 (担当:単著範囲:7章神経回路網における情報処理と統合(ダイナミックな反射制御))
    丸善出版 2018年 808 376-377
  • 昆虫と自然・特集「昆虫の生物音響学」
    西野 浩史, 渡邉 英博 (担当:共著範囲:振動・聴覚受容器のかたちとはたらき)
    ニューサイエンス社 2015年
  • 生物模倣技術と新材料・新製品開発への応用
    高梨 琢磨, 西野 浩史 (担当:共著範囲:第2章 生物の五感に学ぶ機能とその製品開発への応用 第9節 昆虫の振動情報と受容器に学ぶ-振動情報を受容する仕組み、その応用の可能性)
    技術情報協会 2014年
  • Invertebrate Learning and Memory (eds. Randolf Menzel and Paul Benjamin)
    西野 浩史 (担当:共著範囲:Olfactory and visual learning in cockroaches and crickets)
    Academic Press 2013年
  • 生物科学
    高梨 琢磨, 深谷 緑, 小池 卓二, 西野 浩史 (担当:共著範囲:昆虫における振動情報の機能解明と害虫防除への応用)
    農文協 2013年
  • 動物の多様な生き方(全5巻)2.動物の生き残り術:行動とそのしくみ
    西野 浩史 (担当:分担執筆範囲:昆虫の擬死:無駄な抵抗はやめよう)
    共立出版 2009年
  • 昆虫ミメティクス〜昆虫の設計に学ぶ〜第2編第9節
    西川 道子, 西野 浩史 (担当:分担執筆範囲:昆虫の嗅覚糸球体)
    2008年
  • 昆虫ミメティクス〜昆虫の設計に学ぶ〜第2編第22節
    西野 浩史 (担当:分担執筆範囲:昆虫の擬死:多細胞センサーを介した運動抑止機構)
    NTS 2008年
  • Biophilia
    西野 浩史 (担当:分担執筆範囲:昆虫が「死んだふり」をするわけーコオロギに学ぶ擬死行動の機能としくみ)
    アドスリー 2008年
  • バイオとナノの融合I 新生命科学の基礎 「進化がうみだしたもうひとつの耳-昆虫の聴覚器官研究の最前線-」
    北海道大学出版会 2007年
  • 比較生理生化学
    藍 浩之, 西野 浩史 (担当:共著範囲:ジョンストン器官の比較形態学:構造と中枢投射)
    2007年

講演・口頭発表等

  • 環境にやさしい飛来虫低減へのとりくみーアカデミックな知見を中心にー  [招待講演]
    西野 浩史
    第二回SILaWay合同報告会 2019年04月 口頭発表(招待・特別)
  • ナミアゲハのメス成虫におけるミカン葉抽出物提示時の活動脳領域の解析  [通常講演]
    宇賀神 篤, 西野 浩史, 尾崎 克久
    第63回応用動物昆虫学会 2019年 筑波大学
  • 増谷直輝, 小松正宏, 西野浩史
    土木学会年次学術講演会講演概要集(CD-ROM) 2018年08月
  • 宇賀神篤, 西野浩史, 尾崎克久
    日本応用動物昆虫学会大会講演要旨 2018年03月
  • 小松 正宏, 増谷 直輝, 栗原 啓伍, 西野 浩史
    「野生生物と交通」研究発表会講演論文集 2018年02月
  • 昆虫の生理メカニズムに基づく環境にやさしい飛来虫制御ー見え始めた光ー  [通常講演]
    西野 浩史
    SILaWay合同報告会 2018年 NEXCO東日本北海道支社 
    演者忌引きのため代理で増谷直輝(NEXCO東日本)が代理発表
  • Vibration sensitivity in a cerambycid pest and its potential for pest management  [通常講演]
    T. Takanashi, H. Nishino
    2nd International Symposium on Biotremology 2018年 Riva del Garda, Trento, Italy
  • 昆虫の聴覚・振動受容器-発見と観察のテクニック  [通常講演]
    西野 浩史
    昆虫分類学若手懇談会シンポジウム「昆虫の発音と振動-その多様なアプローチ」 2018年 名城大学天白キャンパス(名古屋市)
  • 高速道路の飛来虫に関する研究  [通常講演]
    小松 正宏, 増谷 直輝, 栗原 啓伍, 西野 浩史
    第17回 「野生生物と交通」研究発表会 2018年 札幌市教育文化会館
  • 不動の神経メカニズムー擬死の進化的起源を探るー  [通常講演]
    西野 浩史
    第65回日本生態学会全国大会 W20自由集会 「昆虫の動きと不動を科学する」:生理学と生態学の融合を目指して 2018年 札幌コンベンションセンター 
    発表は3月17日
  • ナミアゲハ食草認識における脳の寄与の検討  [通常講演]
    宇賀神 篤, 西野 浩史, 尾崎 克久
    第62回日本応用動物昆虫学会大会 2018年 鹿児島大学郡元キャンパス
  • Neural representation of spatial odour perception in the American cockroach  [通常講演]
    M. Paoli, E. Couzin-Fuchs, M. Sekulic, H. Nishino, G. C. Galizia
    International Congress of Neuroethology 2018 2018年 Brisbane, Australia
  • ワモンゴキブリの嗅覚局所受容野の形成機構  [通常講演]
    渡邉 英博, 小池 雪乃, 立石 康介, 堂前 愛, 西野 浩史, 横張 文男
    日本動物学会第89回札幌大会 2018年 札幌市コンベンションセンター
  • 明瞭分離された2つの嗅覚経路は気流情報を符号化する  [通常講演]
    西野 浩史, 堂前 愛
    日本動物学会第89回札幌大会 2018年 札幌市コンベンションセンター
  • Sex pheromone processing in Turkestan cockroach  [通常講演]
    H. Nishino, M. Domae
    日本比較生理生化学会 第40回神戸大会 2018年 神戸大学先端融合研究環統合研究拠点コンベンションホール 
    短い口頭発表もあり
  • 古賀晴華, 渡邉英博, 西野浩史, 北條優, 大村和香子, 高梨琢磨, 横張文男
    日本応用動物昆虫学会大会講演要旨 2017年03月
  • 向井 裕美, 西野 浩史, スカルス ニールス, 高梨 琢磨
    第61回日本応用動物昆虫学会大会 2017年03月 東京農工大学小金井キャンパス
  • 田中 真史, 加藤 巧, 西野 浩史, 大門 高明
    第61回日本応用動物昆虫学会大会 2017年03月 東京農工大学小金井キャンパス
  • Spatial odor coding in the cockroach  [通常講演]
    H. Nishino
    Mini symposium for olfactory processing in insects 2017年 University of Konstanz 
    invited there as a mentor of the "mentorship Programme"
  • シロアリの触角葉糸球体構成のカースト間比較  [通常講演]
    古賀 晴華, 渡邉 英博, 西野 浩史, 北條 優, 大村 和香子, 横張 文男
    第61回日本応用動物昆虫学会大会 2017年 東京農工大学(東京都小金井市)
  • How the cockroach brain can encode spatial olfactory information  [通常講演]
    M. Paoli, H. Nishino, G. C. Galizia
    G?ttingen School 2017年 G?ttingen School, G?ttingen, Germany
  • Interspecies and intercaste comparisons of antennal lobe constitution in seven species of termite  [通常講演]
    H. Koga, H, Watanabe,H. Nishino, M. Hojo, W. Omura, T. Takanashi, F. Yokohari
    2017 ISCE/APACE 2017年 Fukakusa Campus, Ryukoku University, Kyoto, Japan
  • Vibration sensitivity in cerambycid beetles and its potential for pest control  [通常講演]
    T. Takanashi, S. Fukui, T. Koike, H. Nishino
    17th Invertebrate Sound and Vibration Meeting 2017年 Schloss Rauischholzhausen, Giessen
  • Axonal layer-dependent dendritic organization of Kenyon cells in a hemimetabolous insect  [通常講演]
    H. Nishino, K. Katoh, M. Domae
    JSCPB 2017 Fukuoka 2017年 Fukuoka University (Fukuoka City)
  • Comparative study of antennal lobe glomeruli in seven species of termites  [通常講演]
    H. Koga, H, Watanabe,H. Nishino, M. Hojo, W. Omura, T. Takanashi, F. Yokohari
    JSCPB 2017 Fukuoka 2017年 Fukuoka University (Fukuoka City) 
    大会委員長賞受賞
  • Postembryonic development of sex pheromone-receptive olfactory sensory neurons in the cockroach  [通常講演]
    Watanabe Hidehiro, Koike Yukino, Nishino Hiroshi, Yokohari Fumio
    CHEMICAL SENSES 2016年11月
  • 加藤 巧, 岩崎 正純, 水波 誠, 西野 浩史
    日本昆虫学会第76回大会・第60回日本応用動物昆虫学会・合同大会 2016年03月 大阪府立大学・中百舌鳥キャンパス(堺市)
  • 7種のシロアリの触角葉糸球体構成の比較解析  [通常講演]
    古賀 晴華, 渡邉 英博, 西野 浩史, 北條 優, 大村 和香子, 高梨 琢磨, 横張 文男
    動物学会・植物学会・生態学会三学会合同鹿児島大会 2016年 鹿児島大学
  • Olfactory processing via temporally and spatially segregated parallel pathways in an insect brain.  [通常講演]
    H. Watanabe, H. Nishino, M. Mizunami, F. Yokohari
    Environmental Sensing and Animal Behavior(ESAB) 2016年 東京大学
  • Distribution of putative octopaminergic and tyraminergic neurons in a cockroach brain  [通常講演]
    K. Terao, T, Watanabe,H. Aonuma, H. Nishino, M. Mizunami
    JSCPB 2016 Tokyo 2016年 玉川大学(東京・町田市)
  • Activity of a pheromone-responsive projection neuron is inhibited by pheromonal stimulation to the contralateral antenna.  [通常講演]
    H. Nishino, K. Katoh, M. Iwasaki, N. Takahashi, H. Watanabe
    JSCPB 2016 Tokyo 2016年 玉川大学(東京・町田市)
  • Aggregation pheromone processing in a cockroach brain  [通常講演]
    K. Katoh, N. Takahashi, H, Watanabe,M. Mizunami, H. Nishino
    JSCPB 2016 Tokyo 2016年 玉川大学(東京・町田市) 
    大会委員長賞受賞
  • Complete identification of four calycal giant interneurons in an insect brain.  [通常講演]
    N. Takahashi, K. Katoh, H, Watanabe,M. Mizunami, H. Nishino
    日本動物学会第87回沖縄大会 2016 The 87th Annual Meeting of the Zoological Society of Japan 2016年 沖縄コンベンションセンター(宜野湾市)
  • Vibration sensitivity in cerambycid beetles and its potential for insect pest control  [通常講演]
    T. Takanashi, H, Sakamoto, N. Skals, S. Fukui, Y. Matsui, T. Koike, H. Nishino
    日本動物学会第87回沖縄大会 2016 The 87th Annual Meeting of the Zoological Society of Japan 2016年 沖縄コンベンションセンター(宜野湾市)
  • Two parallel coding strategies to process general odor in basal insects  [通常講演]
    H. Watanabe, H. Nishino, M. Mizunami, F. Yokohari
    日本動物学会 第87回 沖縄大会 2016 The 87th Annual Meeting of the Zoological Society of Japan 2016年 沖縄コンベンションセンター(宜野湾市)
  • Similarity and variability of glomerular organizations of the antennal lobes in seven species of termites  [通常講演]
    H. Koga, H, Watanabe,H. Nishino, M. Hojo, W. Omura, T. Takanashi, F. Yokohari
    日本動物学会第87回沖縄大会2016 The 87th Annual Meeting of the Zoological Society of Japan 2016年 沖縄コンベンションセンター(宜野湾市)
  • A neuron coding odor direction  [通常講演]
    H. Nishino, M. Iwasaki, N. Takahashi, K. Katoh, A. Matsushita
    日本動物学会第87回沖縄大会 2016 The 87th Annual Meeting of the Zoological Society of Japan 2016年 沖縄コンベンションセンター(宜野湾市)
  • Male jewel bug localizes female calling vibrations: directional vibration sensing by chordotonal organs  [通常講演]
    H. Mukai, H. Nishino, N. Skals, T. Takanashi
    第3回生物音響学会年次研究発表会 2016年 伊良湖シーパーク & スパ(愛知県田 原市伊良湖町宮下) 
    生物音響学会最優秀賞受賞
  • 向井裕美, 西野浩史, 高梨琢磨
    日本応用動物昆虫学会大会講演要旨 2015年03月
  • 求愛シグナルの振動を脚で感知する:キンカメムシ類における振動受容機構の解明  [通常講演]
    向井 裕美, 西野 浩史, 高梨 琢磨
    応用動物昆虫学会第59回大会 2015年 山形大学小白川キャンパス
  • Vibratory signals detected by leg chordotonal organs enhance mating success in a jewel bug  [通常講演]
    H. Mukai, H, Nishino,T. Takanashi
    15th International Meeting on Invertebrate Sound & Vibration 2015年 Lord Elgin Hotel, Ottawa, Ontario
  • Substrate vibrations mediate behavioral responses via leg chordotonal organ in the Japanese pine sawyerbeetle  [通常講演]
    T. Takanashi, M. Fukaya, H. Nishino
    15th International Meeting on Invertebrate Sound & Vibration 2015年 Lord Elgin Hotel, Ottawa, Ontario
  • マツノマダラカミキリ弦音器官がもつセロトニン免疫陽性の細胞内微細構造  [通常講演]
    渡邉 英博, 西野 浩史, 高梨 琢磨, 横張 文男
    日本動物学会第86回大会 2015年 朱鷺メッセ(新潟市)
  • 単一ニューロンによる匂いの方向検出  [通常講演]
    西野 浩史, 岩崎 正純, 加藤 巧, 高橋 直美
    日本動物学会第86回大会 2015年 朱鷺メッセ(新潟市)
  • Traditional insect hearing organ revisited: key anatomical feature for frequency discrimination  [通常講演]
    西野 浩史
    CompBiol 2015 広島大会 2015年 JMS アステールプラザ (広島市中区加古町)
  • Dormitory effect in cockroaches: synchronization of assexual ootheca production in females  [通常講演]
    加藤 巧, 岩崎 正純, 水波 誠, 西野 浩史
    CompBiol 2015 広島大会 2015年 JMS アステールプラザ (広島市中区加古町)
  • Complete identification of four types of calycal giant interneurons in an insect brain  [通常講演]
    高橋 直美, 加藤 巧, 渡邉 英博, 水波 誠, 西野 浩史
    CompBiol 2015 広島大会 2015年 JMS アステールプラザ (広島市中区加古町) 
    大会会長賞(1位)受賞
  • 西野 浩史
    日本化学会第94春季年会 ATP交流会 新材料開発最前線 連携が支えるバイオミメティクス 2014年03月 名古屋大学 東山キャンパス
  • 岩崎 正純, 西野 浩史
    第58回日本応用動物昆虫学会大会 2014年03月 高知大学朝倉キャンパス
  • 椿 玲未, 細田 奈麻絵, 北島 博, 深谷 緑, 神崎 菜摘, 小池 卓二, 黒田 克史, 森 直樹, 西野 浩史, 野村 周平, 土原 和子, 矢崎 健一, Voigt Dagmar, 高梨 琢磨
    日本化学会第94春季年会 ATP交流会 新材料開発最前線 連携が支えるバイオミメティクス 2014年03月 名古屋大学 東山キャンパス
  • Sensing vibration in land bugs: the unusual morphologies of leg chordotonal organs  [通常講演]
    H. Mukai, H, Nishino,T. Takanashi
    The 19th Auditory Research Forum 2014年 Doshisha Biwako Retreat Center, Doshisha University
  • Vibration signals in insects and their application to pest control  [通常講演]
    T. Takanashi, W. Kojima, H. Nishino
    Joint International Symposium on Nature-Inspired Technology 2014 and Engineering Neo-Biomimetics V 2014年 札幌
  • Substrate vibrations mediate startle behavior via femoral chordotonal organ in a cerambycid beetle  [通常講演]
    T. Takanashi, M. Fukaya, H. Nishino
    11th International Congress of Neuroethology 2014年 Convention Center, sapporo
  • Temporal activity patterns of two different types of projection neurons revealed by simultaneous intracellular recordings in the cockroach  [通常講演]
    H. Watanabe, H. Nishino, F. Yokohari
    11th International Congress of Neuroethology 2014年 Convention Center, Sapporo
  • Sensing the structural architecture of odor plumes with a single antenna  [通常講演]
    H. Nishino, M. Iwasaki, A. Yoritsune, I. Kamimura, M. Mizunami
    11th International Congress of Neuroethology 2014年 Convention Center, Sapporo
  • 岩崎 正純, 西野 浩史
    日本動物学会第84回大会 2013年08月 岡山大学(岡山市)
  • 西野 浩史, 岩崎 正純
    日本動物学会第84回大会 2013年08月 岡山大学(岡山市)
  • 中山雄太, 西野浩史, 水波誠
    日本動物学会大会予稿集 2012年08月
  • 市川 敏夫, 大久保 和彦, 藤 義博, 西野 浩史
    日本動物学会第83回大会 2012年08月 大阪大学豊中キャンパス
  • 西野 浩史, 岩崎 正純, 頼経 篤史, 上村 逸郎
    日本動物学会第83回大会 2012年08月 大阪大学豊中キャンパス
  • 西野 浩史
    第56回日本応用動物昆虫学会大会 小集会:昆虫音響学への招待ー振動感覚と行動 2012年03月 奈良市・近畿大学農学部
  • 岩崎 正純, 水波 誠, 西野 浩史
    日本動物学会第82回大会 2011年08月 旭川市大雪クリスタルホール
  • 泰山 浩司, 松村 龍成, 夏秋 友香, 西川 道子, 横張 文男, 西野 浩史
    日本動物学会第82回大会 2011年08月 旭川市大雪クリスタルホール
  • 西野 浩史, 岩崎 正純, 上村 逸郎
    日本動物学会第82回大会 2011年08月 旭川市大雪クリスタルホール
  • 高梨琢磨, 久保島吉貴, 深谷緑, 西野浩史, 菅谷章洋, 小池卓二
    日本応用動物昆虫学会大会講演要旨 2011年03月
  • 化学生態学への神経行動学的アプローチ:ゴキブリの性フェロモンコミュニケーション  [通常講演]
    西野 浩史
    第6回化学生態学研究会 2011年 湯の川プリンスホテル渚亭(函館)
  • 泰山 浩司, 松村 龍成, 有井 達夫, 村田 和義, 夏秋 友香, 西川 道子, 横張 文男, 西野 浩史
    日本動物学会中国四国支部大会2011 2011年 香川大学幸町北キャンパス
  • Detection of female sex pheromone by male and female cockroaches: a comparative study  [通常講演]
    H. Nishino, M. Iwasaki, M. Mizunami
    ICCPB2011 2011年 Nagoya Congress Center
  • 泰山浩司, 松村龍成, 有井達夫, 夏秋友香, 西川道子, 横張文男, 西野浩史
    日本動物学会大会予稿集 2010年08月
  • 高梨 琢磨, 深谷 緑, 西野 浩史
    日本動物学会第81回大会 2010年08月 東京大学教養部(駒場キャンパス)
  • 高梨 琢磨, 深谷 緑, 西野 浩史
    聴覚研究会資料 2010年05月
  • 深谷緑, 西野浩史, 高梨琢磨
    日本応用動物昆虫学会大会講演要旨 2010年03月
  • 高梨琢磨, 深谷緑, 久保島吉貴, 石田厚, 神崎菜摘, 中野亮, 小池卓二, 西野浩史
    日本応用動物昆虫学会大会講演要旨 2010年03月
  • 昆虫の単一嗅覚介在ニューロンの挙動から脳高次機能を探る:その有用性と限界  [通常講演]
    西野 浩史
    文部科学省「物質・デバイス領域共同研究拠点」複雑系数理とその応用に関するシンポジウム 2010年 北海道大学電子科学研究所1階会議室
  • 振動に対するマツノマダラカミキリの反応性及びマツの「自己」振動の特性  [通常講演]
    高梨 琢磨, 深谷 緑, 久保島 吉貴, 石田 厚, 神崎 菜摘, 中野 亮, 小池 卓二, 西野 浩史
    日本応用動物昆虫学会第54回大会 2010年 千葉大学・西千葉キャンパス
  • マツノマダラカミキリの触角「迎え打ち」反応における視覚情報と振動情報の協力作用  [通常講演]
    深谷 緑, 西野 浩史, 高梨 琢磨
    日本応用動物昆虫学会第54回大会 2010年 千葉大学・西千葉キャンパス
  • 渡邉 英博, 西野 浩史, 西川 道子, 横張 文男
    日本比較生理生化学会第32回大会 2010年 九州産業大学
  • 西野 浩史, 岩崎 正純
    日本比較生理生化学会第32回大会 2010年 九州産業大学
  • Dual pathways to process general odors in the cockroach brain  [通常講演]
    H. Watanabe, H. Nishino, M. Nishikawa, F. Yokohari
    9th International Congress of Neuroethology 2010年 Salamanca
  • 高梨 琢磨, 中牟田 潔, Skals Neils, 西野 浩史
    第53回応用動物昆虫学会 2009年03月 北海道大学(札幌市)
  • Sex-specific antennal sensilla of the carpenter ant Camponotus japonicus.  [通常講演]
    A. Nakanishi, H. Nishino,H, Watanabe, F. Yokohari, M. Nishikawa
    Memorial Symposium for the 25th International Prize for Biology "Biology of Sensing" Celebrating Dr. Winslow R. Briggs 2009年 Shiran Kaikan, Kyoto University
  • 昆虫脳の単一ニューロンの活動記録・染色法  [通常講演]
    岩崎 正純, 池田 正幸, 西野 浩史
    第15回低温科学研究所技術報告会 2009年 北大・低温研・2階講義室
  • Analysis of the neural processings of thermo and hygrosensory signal in the insect brain  [通常講演]
    H. Watanabe, H. Nishino, M. Nishikawa, F. Yokohari
    Australlian Neuroscience Society 29th Annual Meeting 2009年 Canberra
  • ワモンゴキブリ触角葉における糸球体構成  [通常講演]
    渡邉 英博, 西野 浩史, 西川 道子, 横張 文男
    第62回動物学会九州支部大会 2009年 宮崎大学
  • クロオオアリ触角の性的二形と鞭節感覚子  [通常講演]
    中西 あき, 西野 浩史, 渡邉 英博, 横張 文男, 西川 道子
    第62回日本動物学会九州支部大会 2009年 宮崎大学
  • クロオオアリ触角葉における雌特異的糸球体群  [通常講演]
    中西 あき, 西野 浩史, 渡邉 英博, 横張 文男, 西川 道子
    日本動物学会第80回大会 2009年 静岡グランシップ
  • クロオオアリ触角における雌特異的感覚子  [通常講演]
    中西 あき, 西野 浩史, 渡邉 英博, 横張 文男, 西川 道子
    日本動物学会第80回大会 2009年 静岡グランシップ
  • ワモンゴキブリ嗅覚投射ニューロンの時空間的情報処理  [通常講演]
    渡邉 英博, 西野 浩史, 西川 道子, 横張 文男
    日本動物学会第80回大会 2009年 静岡グランシップ
  • 昆虫の嗅覚糸球体はダイナミックな発生過程をたどる  [通常講演]
    西野 浩史, 頼経 篤史, 岩崎 正純
    日本動物学会第80回大会 2009年 静岡グランシップ
  • 中西 あき, 西野 浩史, 渡邉 英博, 横張 文男, 西川 道子
    日本比較生理生化学会第31回大会CompBiol2009 2009年 大阪(千里ライフサイエンスセンター)
  • ゴキブリ嗅覚情報処理過程における触角葉局所介在ニューロンの役割  [通常講演]
    渡邉 英博, 西野 浩史, 西川 道子, 横張 文男
    日本比較生理生化学会第31回大会CompBiol2009 2009年 大阪(千里ライフサイエンスセンター)
  • 西野 浩史, 頼経 篤史
    日本比較生理生化学会第31回大会CompBiol2009 2009年 大阪(千里ライフサイエンスセンター)
  • Nishino Hiroshi, Nishikawa Michiko, Yokohari Fumio
    COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY B-BIOCHEMISTRY & MOLECULAR BIOLOGY 2008年12月
  • 渡邉英博, 西野浩史, 横張文男
    日本動物学会大会予稿集 2008年08月
  • 西野 浩史, 岩崎 正純
    日本動物学会第79回大会 2008年08月 福岡大学
  • Topographic organization of olfactory afferents: insights into evolution of olfactory sensory system in insects  [通常講演]
    H. Nishino
    International seminar: Evolutionary Studies in Behavioral Neuroscience 2008年 湘南国際村センター
  • 西野 浩史, 西川 道子, 横張 文男
    日本比較生理生化学会第30回大会 2008年 北海道大学
  • ワモンゴキブリ前大脳における湿度情報処理の神経生理学的解析  [通常講演]
    渡邉 英博, 西野 浩史, 横張 文男
    日本動物学会第79回大会 2008年 福岡大学
  • Nishino Hiroshi
    COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY B-BIOCHEMISTRY & MOLECULAR BIOLOGY 2007年11月
  • Nishikawa Michiko, Nishino Hiroshi, Nakanishi Aki, Natsuaki Yuka, Yokohari Fumio
    COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY B-BIOCHEMISTRY & MOLECULAR BIOLOGY 2007年11月
  • 西川 道子, 西野 浩史, 中西 あき, 夏秋 友香, 横張 文男
    日本動物学会第78回大会 2007年08月 弘前大学
  • 西野浩史
    日本比較生理生化学会大会予稿集 2007年
  • 西川 道子, 西野 浩史, 中西 あき, 夏秋 友香, 横張 文男
    第29回日本比較生理生化学会 2007年 岡山大学
  • 匂い受容細胞の3次元的位置情報は糸球体中にマッピングされるか?  [通常講演]
    西野 浩史
    第29回日本比較生理生化学会 2007年 岡山大学
  • Somatotopic projection of sensory afferents of Johnston's organ in the honybee brain  [通常講演]
    H. Ai, H. Nishino, T. Ito
    The Eighth International Congress of Neuroethology 2007年 University of British Columbia (Vancouver)
  • Topographic organization of olfactory and contact chemosensory afferents in an insect brain.  [通常講演]
    H. Nishino
    The 4th Asia-Pacific Conference on Chemical Ecology 2007年 Tsukuba
  • Polymorphism in the antennal lobe structure of the carpenter ant  [通常講演]
    Nishikawa Michiko, Nishino Hiroshi, Tsuji Eriko, Misaka Yuko, Kubota Maiko, Satoji Yuji, Ozaki Mamiko, Yokohari Fumio
    ZOOLOGICAL SCIENCE 2006年12月
  • Ai Hiroyuki, Nishino Hiroshi, Itoh Tsunao
    COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY B-BIOCHEMISTRY & MOLECULAR BIOLOGY 2006年11月
  • Nishino Hiroshi, Nishikawa Michiko, Yokohari Fumio
    COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY B-BIOCHEMISTRY & MOLECULAR BIOLOGY 2006年11月
  • 西川 道子, 西野 浩史, 辻 衣里子, 三坂 優子, 久保田 麻衣子, 里路 裕司, 尾崎 まみこ, 横張 文男
    日本比較生理生化学会第28回大会 2006年 浜松
  • 藍 浩之, 西野 浩史, 伊藤 綱男
    日本比較生理生化学会第28回大会 2006年 浜松
  • 西野 浩史, 西川 道子, 横張 文男
    日本比較生理生化学会第28回大会 2006年 浜松
  • Anatomical substrate for spatial representation of location of odor in an insect brain  [通常講演]
    Nishino Hiroshi
    ZOOLOGICAL SCIENCE 2005年12月
  • 西野 浩史
    第27回日本比較生理生化学会 2005年 電気通信大学
  • 聴覚の収斂進化-昆虫の聴覚器官が教えてくれること-  [通常講演]
    西野 浩史
    第7回日本進化学会 2005年 仙台
  • 匂いの位置情報の脳内表現  [通常講演]
    西野 浩史
    日本動物学会第76回大会 2005年 つくば国際会議場
  • Anatomy of sensory afferents of sensilla chaetica in cockroach antennae  [通常講演]
    Nishino Hiroshi, Nishikawa Michiko, Yokohari Fumio
    ZOOLOGICAL SCIENCE 2004年12月
  • Central projections of antennal and maxillary palpal afferents in the brain of the cockroach, Periplaneta americana  [通常講演]
    Nishikawa Michiko, Nishino Hiroshi, Yokohari Fumio
    ZOOLOGICAL SCIENCE 2004年12月
  • コオロギ触角感覚情報の中枢処理経路  [通常講演]
    高原 里佳, 西野 浩史, 西川 道子, 横張 文男
    第26回日本比較生理生化学会 2004年 神戸大学
  • Olfactory signal processing in the lateral protocerebrum of the cockroach brain  [通常講演]
    H. Nishino, H. Hongo, M. Mizunami
    The 7th Congress of the International Society for Neuroethology 2004年 Nyborg
  • Insects smell humidity and temperature  [通常講演]
    H. Nishino, M. Nishikawa, S. Yamashita, Y. Yamazaki, M. Mizunami, F. Yokohari
    The 7th Congress of the International Society for Neuroethology 2004年 Nyborg
  • コオロギ触角・小腮鬚感覚情報の中枢投射  [通常講演]
    西川 道子, 西野 浩史, 横張 文男
    日本動物学会第75回大会 2004年 神戸
  • ゴキブリ触角上の剛毛感覚子の軸索地図  [通常講演]
    西野 浩史, 西川 道子, 横張 文男
    日本動物学会第75回大会 2004年 神戸
  • コオロギ死にまね行動の神経機構  [通常講演]
    西野 浩史
    日本比較生理生化学会 第25回大会 2003年 仙台 
    吉田奨励賞受賞者講演
  • ウェタ聴覚器官の機能解剖  [通常講演]
    西野 浩史
    日本比較生理生化学会 第25回大会 2003年 仙台
  • ゴキブリ高次嗅覚情報処理ニューロンの生理学的性質  [通常講演]
    西野 浩史, 本郷 秀紀, 水波 誠
    日本動物学会第74回大会 2003年 函館大学
  • 西野 浩史
    日本生理学会北海道地方会第82回大会 2002年10月 札幌
  • How do the brains of cockroaches differ from those of social Hymenoptera?  [通常講演]
    M. Mizunami, H. Nishino
    14th International Congress of IUSSI(国際社会性昆虫学会議) 2002年 北海道大学学術交流会館
  • ゴキブリの前大脳側葉部での匂い情報処理  [通常講演]
    本郷 秀紀, 西野 浩史, 水波 誠
    日本動物学会第73回大会 2002年 金沢大学
  • コオロギ死にまね行動における脛節屈筋運動ニューロンの機能的役割  [通常講演]
    西野 浩史
    日本動物学会第73回大会 2002年 金沢大学
  • Inhibition of startle response to sensory stimuli during thanatosis is modality-Specific  [通常講演]
    M. Sakai, K. Tanizawa, H. Nishino
    International Symposium: Neuronal organization and plasticity in the microbarin system 2001年 Tsukuba
  • Input neurons in calyces of mushroom bodies of cockroach brain  [通常講演]
    M. Nishikawa, H. Nishino, M. Mizunami, F. Yokohari
    International Symposium: Neuronal organization and plasticity in the microbarin system 2001年 Tsukuba
  • Oligoglomerular projection neurons in the cockroach brain  [通常講演]
    H. Nishino, S. Yamashita, Y. Yamazaki, M. Nishikawa, F. Yokohari, M. Mizunami
    International Symposium: Neuronal organization and plasticity in the microbarin system 2001年 Tsukuba
  • ゴキブリの脳のキノコ体出力ニューロンの形態と匂い応答  [通常講演]
    山下 新吾, 西野 浩史, 水波 誠
    日本動物学会第72回大会 2001年 福岡
  • キノコ体傘部入力ニューロンと感覚モダリティー  [通常講演]
    西川 道子, 西野 浩史, 水波 誠, 横張 文男
    日本動物学会第72回大会 2001年 福岡
  • ゴキブリの湿度・温度受容性介在ニューロン  [通常講演]
    西野 浩史, 山崎 吉之, 西川 道子, 横張 文男, 水波 誠
    日本動物学会第72回大会 2001年 福岡
  • 山崎吉之, 西野浩史, 水波誠
    日本動物学会大会予稿集 2000年09月
  • 西野浩史
    日本動物学会大会予稿集 2000年09月
  • 谷沢和紀, 小西ゆかり, 西野浩史, 酒井正樹
    日本動物学会大会予稿集 1999年09月
  • 小西ゆかり, 谷沢和紀, 西野浩史, 酒井正樹
    日本動物学会中国四国支部会報 1999年05月
  • 山崎吉之, 西野浩史, 水波誠
    日本動物学会大会予稿集 1998年09月
  • 小西ゆかり, 西野浩史, 酒井正樹
    日本動物学会大会予稿集 1998年09月
  • 小西ゆかり, 西野浩史, 酒井正樹
    日本動物学会中国四国支部会報 1998年05月
  • 西野浩史, 水波誠
    日本動物学会大会予稿集 1997年10月
  • 西野浩史, 酒井正樹
    日本動物学会大会予稿集 1995年09月
  • 西野浩史, 酒井正樹
    日本動物学会大会予稿集 1994年10月
  • 西野浩史, 酒井正樹
    日本動物学会大会予稿集 1993年11月
  • 西野浩史, 酒井正樹
    日本動物学会中国四国支部会報 1992年05月
  • 西野浩史, 酒井正樹
    日本動物学会中国四国支部会報 1991年05月

その他活動・業績

特許

  • 高梨 琢磨, 大村 和香子, 大谷 英児, 久保島 吉貴, 森 輝夫, 小池 卓二, 西野 浩史  国立研究開発法人森林総合研究所, 国立大学法人電気通信大学, 国立大学法人北海道大学  201603010506001087
  • 高梨 琢磨, 大村 和香子, 大谷 英児, 久保島 吉貴, 森 輝夫, 小池 卓二, 西野 浩史  独立行政法人森林総合研究所, 国立大学法人電気通信大学, 国立大学法人北海道大学  201303052542486463

受賞

  • 2011年09月 日本動物学会 成茂科学振興賞
     昆虫の擬死の神経メカニズムの解明 
    受賞者: 西野 浩史
  • 2003年07月 吉田奨励賞
     コオロギ死にまね行動の神経機構 
    受賞者: 西野 浩史

共同研究・競争的資金等の研究課題

  • 嗅覚並行処理経路の統合様式の解明
    日本学術振興会:科学研究費助成事業 基盤研究(C)
    研究期間 : 2020年04月 -2023年03月 
    代表者 : 西野 浩史
  • 不完全変態昆虫の成長に伴う性フェロモン受容・処理経路の発達
    日本学術振興会:科学研究費助成事業 基盤研究(C)
    研究期間 : 2019年04月 -2022年03月 
    代表者 : 渡邉 英博, 西野 浩史
  • 明瞭分離された2つの嗅覚経路のシグナルフローの意義の解明
    日本学術振興会:科学研究費助成事業 基盤研究(C)
    研究期間 : 2017年04月 -2020年03月 
    代表者 : 西野 浩史
     
    本研究は多くの動物の嗅覚情報処理経路に共通にみられる並行経路についての具体的な機能や進化的起源についての示唆を得るため、進化的に古い昆虫(ワモンゴキブリ)を用いた形態・生理学的研究を行うものである。 研究開始2年目となるH30年度は当初計画通り、嗅覚情報を処理する単一糸球体投射ニューロン(介在ニューロン)の細胞内記録を行った。記録中には触角に定常的に与えられる気流の速度や加速度に対し、投射ニューロンの自発発火がどのように変化するのかについて調べた。記録後のニューロンには通電による細胞内染色を施し、共焦点レーザー顕微鏡を用いてその形態を詳細に観察した。 その結果、一般臭を処理する投射ニューロンのほとんどが匂い刺激を行わない状態において、1-10 Hz程度の自発発火を示すことがわかった。単一糸球体に樹状突起を持つ投射ニューロンの約半数は気流に対する発火頻度の変化が見られないか、もしくは変化の不明瞭なタイプであり、残り半数が気流に対して明確な発火頻度変化がおこるタイプであった。発火頻度の変化がおこるタイプには流速を徐々に増加することでその自発発火が徐々に増大するものと自発発火が減弱するものが存在した。ただし、記録できたニューロンは全体の3割程度に留まっており、気流情報処理における2つの並行処理経路依存的な違いがあるのかどうかについてはさらなる検討が必要である。 以上の結果は投射ニューロンが匂い情報を処理していない間にも周囲の環境、すなわち、匂いを運ぶ気流についての情報を処理していることを明確に示すものである。本結果の一部については国内学会での発表を行った。
  • 高速道路の飛来虫対策に関する研究
    東日本高速道路(株):共同研究
    研究期間 : 2015年04月 -2020年03月 
    代表者 : 西野浩史
  • Spatial odor coding in insects
    University of Konstanz(DEU):Mentorship Programme
    研究期間 : 2017年04月 -2018年03月 
    代表者 : 西野浩史
  • カミキリムシにおける基質付着の制御機構の解明
    日本学術振興会:科学研究費助成事業 基盤研究(B)
    研究期間 : 2014年04月 -2017年03月 
    代表者 : 高梨 琢磨, 小池 卓二, 細田 奈麻絵, 西野 浩史
     
    昆虫は肢先端に植物などの複雑な基質面に付着できる剛毛を持つ。また、基質を伝わる振動を肢に内在する振動受容器で感知する。本研究では、行動・生理学的実験と付着試験、振動・数理解析から、カミキリムシの基質付着の制御機構を統合的に解明する。そして、付着制御機構を害虫防除技術に応用することを目指す。 1) 付着機能と体表構造の解析 マツノマダラカミキリとラミーカミキリを用いて、肢先端の密生した剛毛の微細構造を走査型電子顕微鏡により観察した。並行して、接着性剛毛の接着試験を行い、特に被着基板表面の化学的性質と接着性の関係を調査した。その結果、基板表面の表面自由エネルギーの内、分散性成分に影響を受けていることが分かった。 2) 振動に対する行動反応性の解析 特定周波数において、持続時間と振幅の振動特性を変化させた合成振動を作成する。これらの合成振動に対するマツノマダラカミキリの行動の反応率より、持続時間と振幅の差異による効果を比較、振動に対する行動反応性を明らかにした。 3) 振動受容器の構造と生理応答性の解析 マツノマダラカミキリを用いて、弦音器官中の感覚細胞を蛍光色素等により染色し、共焦点顕微鏡によって感覚細胞の形態を観察した。感覚細胞に付着する弦などの微細構造や感覚細胞周辺の構造もあわせて解析した。
  • 日本学術振興会:科学研究費助成事業 基盤研究(C)
    研究期間 : 2014年04月 -2017年03月 
    代表者 : 西野 浩史, 松下 敦子
     
    空気中の匂いの分布や移動方向は時々刻々と変化する。このように瞬時に変化する感覚情報を動物がどう読み取り、匂い源に定位するのかは神経科学の重要課題のひとつである。夜行性昆虫の代表格であるゴキブリは採餌や交尾相手の発見を全面的に嗅覚に依存し、視覚的手がかりのない状況でも正確に匂い源に定位できる。申請者は触角全域に分布する性フェロモン応答性の感覚細胞が触角内の三次元的位置に応じて大糸球体内の特定の領域に投射する傾向をもつことを発見した。また、大糸球体から出力する投射ニューロンの1つが触角を横切るフェロモンの方向変化によって顕著に異なる応答パターンを示すことを明らかにした。
  • 日本学術振興会:科学研究費助成事業 新学術領域研究(研究領域提案型)
    研究期間 : 2012年06月 -2017年03月 
    代表者 : 森 直樹, 奥本 裕, 三瀬 和之, 西野 浩史, 光野 秀文, 尾崎 まみこ, 岩佐 達郎, 中村 整, 奥田 隆, 齋藤 正男, 高梨 琢磨, 福田 永
     
    「フェロモンブレンドの受容機構解明とそのモデル構築」と「多成分ブレンドの差分検出における感覚突起のサブセルラー構造の機能」を重点項目と位置付け,研究を展開した。 その結果,2成分系フェロモンブレンドを利用するヒメアトスカシバから各成分に特異的に応答する性フェロモン受容体を同定するとともに、触角における各受容体の発現細胞の割合がフェロモンブレンドの構成比率と類似する傾向を見出した。また,アリは,複合成分で構成される匂いパターンの差分をもとに仲間と非仲間を識別しており,この差分検出には内部神経間の相互連絡を制御するサブセルラー構造が重要な役割を担っていた。
  • 昆虫の聴覚器規範設計の解明
    日本学術振興会:科学研究費助成事業 新学術領域研究(研究領域提案型)
    研究期間 : 2013年04月 -2015年03月 
    代表者 : 西野 浩史
     
    コオロギの前肢の脛節内部にある聴覚器(鼓膜器官)は世界最小クラス(200マイクロメートル四方)であるが、ヒトよりも広い可聴周波数域を有している。本研究では鼓膜器官のサブセルラー構造や物性を精査することにより、システムとしての基本設計を明らかにし、微少振動・聴覚センサーの開発へ向けた具体的知見を得ることを目的とする 本年度は昨年度の解剖学的研究をさらに推し進め、コオロギの鼓膜器官が音受容において、1. 鼓膜の機械的振動、2. 気管による振動増幅、3. 流体(聴覚リンパ液)移動による感覚細胞の機械的刺激、という3つの過程を経ることを明らかにした。このことは鼓膜器官の音受容過程が脊椎動物のそれと似ていることを意味する。振動増幅から流体移動への変換過程では半透明のクチクラ装置が介在しており、これをクチクラコア(cuticle core)と命名した。このクチクラコアはキチン質からなるが、成虫脱皮直後には存在しておらず、約1週間かけて徐々に自己組織化的に形成される。また、脛節の長軸方向に対し感覚細胞を斜めに配置することで省スペースを実現していることがわかった。また、京都大・農学部の森直樹氏、島津製作所との共同研究により、100個体以上のコオロギから基底膜の内部に存在する聴覚リンパ液をガラスキャピラリーを用いて採取し、そのイオン組成を発光分光分析装置(ICPE9000)を用いて調べた。また、北大・工学部の岡嶋孝治氏との共同研究により、聴覚器を構成する組織の粘弾性計測も進めた。 結果を総括すると、コオロギ聴覚器の基本設計については解明することができた一方、リンパ液のイオン組成、聴覚器のサブセルラー領域の粘弾性計測については技術的な難易度の高さに加え、個体差が大きいため、未だに確固とした特徴を得るまでには至っていない。よって達成率は60%と自己評価する。
  • 昆虫における性フェロモンの多面的作用の解明
    住友財団:基礎科学研究助成
    研究期間 : 2012年10月 -2013年10月 
    代表者 : 西野浩史
  • 日本学術振興会:科学研究費助成事業 基盤研究(C)
    研究期間 : 2011年 -2013年 
    代表者 : 西野 浩史
     
    夜行性昆虫の嗅感覚器(触角)は長く、しかも自発的に動くため、匂いの空間分布を捉えるのにすぐれた特徴を持つ。我々は細胞内記録・染色法を用いることによって、オスのゴキブリの触角の基部~先端の特定領域の性フェロモン刺激に応じる介在ニューロン9個を形態学的、生理学的に同定することに成功した。各々のニューロンの樹状突起は大糸球体に入力する感覚細胞の触角上の位置に応じて明瞭に組織化されていた。また、これらのニューロンの軸索終末は多種感覚連合中枢であるキノコ体傘部の異なる領域に投射する一方で、前大脳側葉部には収束していた。以上より、キノコ体が匂いの空間構造の把握に重要な役割を果たすことが示唆された。
  • 擬死における広汎な運動抑止機構の解明
    〔株)成茂製作所:日本動物学会・成茂動物科学基金
    研究期間 : 2011年09月 -2012年09月 
    代表者 : 西野浩史
  • 日本学術振興会:科学研究費助成事業 基盤研究(C)
    研究期間 : 2008年 -2010年 
    代表者 : 西野 浩史
     
    匂いが嗅感覚器のどこに当たっているのかを検出する神経基盤について解剖学、生理学的手法を用いて精査した。その結果、1)ゴキブリの嗅覚求心繊維は触角内の細胞の位置に応じて糸球体中で組織化されているが、この組織化は幼虫期を通じて徐々に発達する、2)介在ニューロンの中には触角の特定領域の匂い刺激にのみ感受性を持つものがある、3)メスにも性フェロモンを特異的に処理する糸球体が存在するが、求心繊維の組織化の程度はオスよりも低く、出力するニューロン数も少ないことが明らかとなった。
  • 昆虫最高次中枢のシステム論的解析
    日本学術振興会:科学研究費助成事業 若手研究(A)
    研究期間 : 2005年 -2007年 
    代表者 : 西野 浩史
     
    当初の計画に沿って研究を進めた。キノコ体関連ニューロン(GABA作働性巨大ニューロンおよびキノコ体出力ニューロン)からの細胞内記録を行い、これらが多種感覚モダリティーに応答すること、さらに各モダリティーのパラメータをその発火パターンの違いによって符号化していることを明らかにした。たとえば、キノコ体出力ニューロンは匂い刺激に対して応答初期において特徴的な抑制性入力が入るが、視覚刺激や機械刺激においては抑制性入力なしの興奮性の応答を示した。また、キノコ体関連ニューロンは匂いの種類の違いに対しては発火の時間的パターンの違い、濃度増加に対してはスパイク応答の増加によって匂いのパラメータを表現している可能性が示唆された。GABA作働性巨大ニューロンの破壊実験については破壊後の個体の生存率が思わしくなく、学習への影響を十分に検証できなかった。現在、個体へのダメージを少なくする手術方法を検討中である。研究過程での最も大きな成果は、匂いの位置や方向の符号化に寄与する神経基盤を発見したことである。プライオリティー確保のため、完全変態昆虫においても同様の検証を行い、関連テーマだけで3本の原著論文として発表することができた。この研究成果については国際学会でも発表し、国外の研究者からも高い評価を受けた。しかし、結果として論文執筆に膨大な時間を割くことになり、生理実験が少しおろそかになったのは反省すべき点と考える。以上、総括すると今年度の研究目的の7割は達成できたと考える。
  • 多細胞化の直接的生存価に関する熱雑音仮説
    日本学術振興会:科学研究費助成事業 萌芽研究
    研究期間 : 2005年 -2006年 
    代表者 : 下澤 楯夫, 青沼 仁志, 西野 浩史
     
    受精卵は卵割を繰り返して単細胞から多細胞へと移行する。受精卵の卵割を、単細胞生物から多細胞へと移行した進化過程のモデルとして扱い、多細胞化が、単細胞に比べて、熱雑音に埋もれた微弱な観測信号の信頼性(情報量)を加算平均化によって改善していることを実証する。 これまでに、コオロギの気流感覚細胞は分子1個の平均運動エネルギー【approximately equal】k_BT(常温で約4×10〜<-21>Joule)に応答できることを実測し、この熱雑音感受性が神経系の基本構造である並列伝送回路の起源であることを示した。 ここで重要なのは、単一分子の熱揺動エネルギーを検出する程の高感度は進化の結果ではなく拘束である、という結論にある。その根拠は、もし細胞がかって低かった感度を上げてk_BT領域に近づいたのなら、自ら熱雑音の中に埋もれて行ったことになり、観測装置としての自殺行為に他ならないからである。時間的空間的に偏った資源環境は、情報伝送速度を上げる向きの淘汰圧として働く。生命誕生前の原始のスープで利用可能なエネルギーは熱揺らぎ幅k_BTの程度であり、このk_BTの程度のエネルギー差を観測して情報(負のエントロピー)に変換する非平衡系が生命である。 生命の起源にとって、k_BTの程度のエネルギー感度は必然である。細胞表面に複数のレセプター分子を並べることも加算平均化になる。観測装置としての細胞が複数結合した加算平均化が生存価を増す。多細胞生物への進化は、単細胞生物に比べて、熱雑音に埋もれた微弱な観測信号の信頼性(情報量)を加算平均化によって改善した例である、ことの情報理論的検証を目的とした。 当初計画は、割球数の増加にともなう膜電位雑音の振幅減少の実測によって、加算平均原理を実証するものであった。しかし膜電位雑音の計測は不安定で卵割前後の比較が困難であった。また代替法として試みた膜電位固定下での電流雑音の計測も不調に終わった。このため、多細胞化の熱雑音仮説の実証は達成できなかったが、その情報論的考察の拡張に寄与した。
  • 神経系はなぜ東なのか-並列構造の起源に関する実験的検証
    日本学術振興会:科学研究費助成事業 基盤研究(B)
    研究期間 : 2003年 -2005年 
    代表者 : 下澤 楯夫, 青沼 仁志, 西野 浩史
     
    神経系はなぜ多数の繊維からなる束なのか?多細胞生物としての当然の帰結なのか?これらの疑問は、つまるところ、神経系は進化の上での如何なる淘汰圧への適応の産物なのか、またその適応にはいかなる拘束条件が付きまとったのか、を問うことである。 情報の生成(観測)にはエネルギー散逸が避けられず、感覚細胞における情報のエネルギーコストは統計熱力学上の理論限界である0.7K_BT[Joule/bit]に近い。本研究は、細胞の熱雑音感受性は進化を通して達成した適応ではなく、生命の起源に遡る拘束であることを明らかにし、資源や危害が時間的空間的に偏在する生存環境は情報伝送(観測)速度増大の淘汰圧として働くこと、それに対する唯一の適応方策は神経細胞の並列化であること、を次のように明らかにした。 1)気流感覚毛で、揺動散逸定理に従ったブラウン運動を観察できることを光学計測によって示した。コオロギ尾葉上の近傍にある二つの気流感覚毛のブラウン運動の無相関性の計測は達成できなかった。 2)気流感覚毛のブラウン運動と感覚細胞の電気的応答の相関(コヒーレンス)の実証には至らなかった。 3)神経細胞は熱雑音領域で動作しており、情報伝送素子としての信号対雑音比が極めて低いことを、実証した。 4)計測と平行して、信号対雑音比の極めて低い神経細胞のパルス列からでも、介在神経へのシナプス加重によって信号を再構成できることを理論的に示した。確率統計学や情報理論で、標本の平均値が母集団の真の平均値から外れる確率が標本数の平方根に反比例して少なくなる「加算平均原理」に着目し、熱雑音に拘束された細胞でも多数による加算平均によって、熱雑音以下の信号の検出精度が向上することを示した。もちろん「束」の前提として多細胞化は必要であるが、多細胞化の直接的生存価自体も、「加算平均原理」で説明できることを示した
  • 昆虫のひずみ受容センサー“ナノスケールの感度を生み出す秘密を探る
    文部科学省:21世紀COE“バイオとナノを融合する新生命科学拠点”事業
    研究期間 : 2002年04月 -2004年03月 
    代表者 : 西野 浩史
  • ゴキブリ高次嗅覚情報処理ニューロンに学ぶ匂い識別・学習のしくみ
    日本学術振興会:科学研究費助成事業 若手研究(B)
    研究期間 : 2003年 -2004年 
    代表者 : 西野 浩史
     
    ゴキブリは我々哺乳類に比してわずか百万分の一以下の脳容量しか持たないにもかかわらず、すぐれた匂い識別能を示し、嗅覚と他の感覚とを連合させて記憶する能力を持つことが知られている。加えて、匂いを処理する高次ニューロンは他の動物に比して格段に大きいことから、無限に存在する匂いを識別・記憶する神経機構を単一ニューロンレベルで解析できる利点をもつ。 昨年度の研究からはキノコ体(最高次嗅覚中枢)の出力側に位置する嗅覚情報処理ニューロンが匂い刺激に対し、1)初期スパイクバーストとそれに続く複雑なスパイク発火パターンからなる二相性の応答を示すこと、2)前者が匂いの濃度を、後者が匂いの質を符号化しているらしいこと、をつきとめた。 今年度はこれらの知見をもとに拘束下のゴキブリにおいて匂い(条件刺激)を触角に、砂糖水(無条件刺激)を触鬚に与えることで古典的条件づけの成立過程におけるニューロンのダイナミックな応答変化を捉えることをこころみた。しかしながら、触鬚固定に伴う侵襲性が高くなるためか、有意な応答変化を捉えることができなかった。そこで味覚刺激を触角に与える侵襲性の少ないパラダイムを新たに開発し、行動実験において良好な結果を得た。現在、本パラダイムを適用した高次ニューロンの細胞内記録、応答の解析を進めている。 一方、味覚系から嗅覚系への神経修飾経路を解明する第一歩として、触角の単一味感覚ニューロンの順行性染色に昆虫で初めて成功した。その軸索は一次嗅覚中枢(触角葉)に近接した領域(背側葉)、および食道下神経節に投射し、末梢における三次元的な細胞体の位置、および味覚のカテゴリーに依存した空間分布を示すことが明らかとなった。以上の成果は国際神経行動学会、日本動物学会等で発表し、高い評価を得た。現在投稿中の論文を含め、二本の論文の執筆を進めている。
  • 神経系の基本構造の起源に関する熱雑音仮設
    日本学術振興会:科学研究費助成事業 萌芽研究
    研究期間 : 2002年 -2003年 
    代表者 : 下澤 楯夫, 西野 浩史, 青沼 仁志, 水波 誠
     
    神経細胞は熱雑音感受性をもっており、そのことが神経系に共通する基本構造である並列伝送回路の起源であることを、1.神経細胞は情報受容に当たってエネルギーを散逸する抵抗体として動作し、揺動散逸定理に従ったブラウン運動を観察できること、2.異なる細胞のブラウン運動は互いに無相関であること、3.感覚細胞がブラウン運動を用いて確率サンプリングした信号は介在神経でシナプス加算によって再構成されること、を実証するため研究を進めてきた。 コオロギ気流感覚毛の機械特性の計測から感覚閾値で感覚細胞が受け取るエネルギーが常温における分子1個の熱揺動エネルギーk_BTに近いこと、閾値付近の刺激に対する応答発火揺らぎの解析から感覚細胞は内部の熱雑音源をパルス符号化に用いるStochastic Samplingで中枢へ信号を送っていること、感覚細胞の情報伝送容量の測定から、信号対雑音比は0.1程度と非常に低いこと、このため情報伝送素子としての細胞1個の性能は400ビット/秒程度に制限されている。 これまでの研究で、気流感覚毛先端のブラウン運動が10nm程度であることを予想して、光学顕微鏡を改造し感覚毛のレーザー照明強拡大像(900倍)を4分割受光素子上に結ばせたブラウン運動計測装置(分解能3nmでの計測が可能)を実用化(平成12年度基盤研究(B)で製作)し、コオロギ気流感覚毛のブラウン運動を光学的に測定した。現在引き続き、2本の気流感覚毛のブラウン運動を同時計測し、近傍のものでも感覚細胞は互いに無相関な熱雑音に曝されていることを実証すべく解析を続けている。
  • コオロギ死にまね行動における運動抑制機構の解明
    日本学術振興会:科学研究費助成事業 若手研究(B)
    研究期間 : 2001年 -2002年 
    代表者 : 西野 浩史
     
    フタホシコオロギは前肢を拘束すると全ての肢を強く屈曲させ、3〜4分間凍り付いたように身動きひとつしなくなるいわゆる"死にまね"をおこす。死にまね中に特異的にみられる生理現象として"カタレプシー"がある。これは屈曲位置にある脛節を強制的に伸展位置まで動かすと新たに与えられた位置を保持し続ける現象で、筋肉が一定の緊張状態と柔軟性を併せ持つ状態と解釈される。本年度はこの独特の硬直姿勢をつくるのに寄与する脛節屈筋を支配する運動ニューロン群の細胞外記録を行い、その発火パターンや頻度を解析ソフト(Lab View)を用いて詳細に調べた。 その結果、死にまね中の姿勢保持に寄与する4個の遅筋タイプの興奮性運動ニューロンの発火頻度は単に静止している状態の発火頻度と違いがみられないことがわかった。両状態においてその総スパイク頻度は脛節の位置に依存して大きく変動した(脛節が伸展位置にあるほど減少する)。さらに死にまね中に特異的に抑制されるユニットを細胞内記録・染色により同定したところ、筋緊張を抑制する機能を持つ抑制性運動ニューロンであることが判明した。つまり、死にまね特有の筋緊張は興奮性運動ニューロンの活動昂進によるものではなく、抑制性運動ニューロンの抑制によりつくられることが強く示唆された。 さらにこの死にまね時特有の運動ニューロンの発火特徴を指標として死にまね誘発時の拘束刺激を受容する自己受容器の探索を行ったところ、両前肢の腿節内弦音器官の除去により死にまね特有の硬直状態が誘発されなくなることがわかった。一方、他の感覚器の除去では全く影響がみられなかった。これにより、死にまね維持への関与が示唆された腿節内弦音器官が死にまね誘発にも関与するという決定的な証拠が得られた。 以上、死にまね行動を特徴づける運動抑制の末梢の神経機構はほぼ解明され、2年間にわたる研究目標はほぼ達成された。
  • 昆虫機械感覚細胞の刺激受容初期過程の力学的研究
    日本学術振興会:科学研究費助成事業 基盤研究(B)
    研究期間 : 2000年 -2002年 
    代表者 : 下澤 楯夫, 西野 浩史, 馬場 欣也, 水波 誠, 青沼 仁志
     
    機械受容は、動物と外界との相互作用の「基本要素」であり、機械刺激の受容機構を抜きにして動物の進化・適応は語れない。従来、機械受容は「膜の張力によるイオンチャネルの開閉」といった「マクロで単純すぎる」図式でとらえられて来た。また、機械感覚の超高感度性の例として、ヒトやクサカゲロウの聴覚閾値での鼓膜の変位量が0.1オングストローム、つまり水素原子の直径の1/10に過ぎないことも、数多く示されてきた。しかし、変位で機械感度を議論するのは明らかに誤っている。感覚細胞は外界のエネルギーを情報エントロピーに変換する観測器であり、その性能はエネルギー感度で表現すべきである。エネルギーの授受無しの観測は「Maxwellの魔物」で代表される統計熱力学上の矛盾に行き着くから、いかなる感覚細胞も応答に際し刺激からエネルギーを受け取っている。コオロギの気流感覚細胞は、単一分子の常温における熱搖動ブラウン運動)エネルギーkBT(300°Kで4×10^<-21>[Joule])と同程度の刺激に反応してしまう。 機械エネルギーが感覚細胞の反応に変換される仕組み、特にその初期過程は全く解明されていない。この未知の細胞機構を解明するため、ブラウン運動に近いレベルの微弱な機械刺激を気流感覚毛に与えたときの感覚細胞の膜電流応答の計測に、真正面から取り組んだ。 長さ約1000μmのコオロギ気流感覚毛を根元から100μmで切断し、ピエゾ素子に取付けた電極を被せてナノメートル領域で動かし、気流感覚細胞の膜電流応答を計測した。長さ1000μmの気流感覚毛の先端は、ブラウン運動によって約14nm揺らいでいることは計測済みである。先端を切除した気流感覚毛を10-100nmの範囲で動かしたときの膜電流応答のエネルギーを計測し、刺激入力として与えた機械エネルギーと比べたところ、すでに10^6倍ほどのエネルギー増幅を受けていた。従って、機械受容器の初期過程は細胞膜にあるイオンチャンネルの開閉以前の分子機構にあることが明らかとなった。
  • 昆虫機械受容系の熱雑音感受性と中枢における微弱信号抽出機構
    日本学術振興会:科学研究費助成事業 特定領域研究(A)
    研究期間 : 2000年 -2001年 
    代表者 : 下澤 楯夫, 青沼 仁志, 西野 浩史, 馬場 欣哉
     
    昆虫の機械受容器は、常温の熱揺動エネルギーk_BT(約4×10^<-21>J、可視光フォトンのエネルギーの1/100)をも検出できる最高度に進化した刺激受容系である。コオロギ気流感覚細胞が熱雑音(ブラウン運動)に揺すられて発火するほど高感度なこと、中枢の介在神経は熱雑音の無相関性を利用して閾値以下の微弱な信号を抽出することを明らかにする目的で本プロジェクトを遂行した。フォトンのような量子を持たない機械受容器、化学受容器、イオンチャンネル、シナプス受容体などは必然的に熱雑音に出会うから、雑音揺らぎやシナプス加重機構が神経系一般に広くみられることなど、情報機械としての神経系が究極の乱数発生器としての熱雑音を利用する設計原理の解明につながる。 コオロギを実験材料に、気流感覚器の機械的構造と感覚細胞のエネルギー変換応答とを分離し、分子熱雑音限界までエネルギー感度を進化させた機械感覚細胞の刺激受容機構解明の手がかりを得、情報機械としての感覚細胞の性質を解明するため感覚細胞が運ぶ情報、感覚細胞が介在神経に伝える情報量の定量化を試みた。中枢の介在神経から記録をとり、閾値付近の気流刺激への応答から、感覚細胞から介在神経への情報伝送量を測定した。コオロギの気流感覚細胞が運ぶ情報量はスパイク1つ当たり2〜4bit。入力感覚繊維1本あたりの情報量はおよそ300bits/secであることを示した。また、中枢の気流感覚介在神経の樹状突起部から細胞内記録をとり、閾値付近の人口白色雑音波形を繰り返し与え、後シナプス集合電位の変動分から、気流から介在神経までの情報伝送量(bits/sec)を測定した結果、50〜200bits/sec程度とばらつきはあるが1個の感覚細胞が伝える情報量より遥かに小さいことがわかった。昆虫の機械受容器は究極感度まで進化し熱雑音に直面している、逆説的に熱雑音のエネルギーと無相関性を利用してさらに微弱な信号を検出する中枢機構が進化したことが示唆された。
  • 昆虫のキノコ体の出力ニューロンの生理・形態学的研究
    日本学術振興会:科学研究費助成事業 基盤研究(C)
    研究期間 : 1997年 -1999年 
    代表者 : 水波 誠, 西野 浩史
     
    昆虫の脳にはキノコ体と呼ばれ高次中枢がある。キノコ体は匂いや場所の連合学習に関わることが示唆されている。本研究では、まず第一に、慢性埋込みワイヤ電極法を用いて、自由行動中のゴキブリのキノコ体出力ニューロンの活動の細胞外記録を行い、41例のユニット記録に成功した。記録されたユニットは感覚刺激に応ずるもの(14例)、行動と関連した活動を示すもの(12例)、感覚刺激に応じかつ行動と関連した活動を示すもの(15例)の3つのタイプに分けられた。行動に関連した活動を示すものには、自己受容器から信号を受け、自己の行動をモニターしていると考えられるもの、運動の方向に依存して活動が変わり、前運動中枢から運動指令のefference copyを受けると考えられるもの、行動の開始に0.2-1秒先行した活動を示し、運動の準備や組み立てに関わるものと考えられるもの、などがあった。これらの結果は、キノコ体が昆虫の自発的運動の企画と遂行において重要な役割を担うことを示唆するものである。 キノコ体は約30の構造単位から形成されるが、次にキノコ体を構造単位とキノコ体出力ニューロンの関係を調べた。出力ニューロンには分節状の樹状突起を持ち、特定の組み合わせのモジュールからの信号を伝えるものがあることが明らかになった。これは、各構造単位がキノコ体からの信号出力における機能的な単位を成していることを示唆するものであった。 さらに、キノコ体出力ニューロンの活動と匂い記憶との関係を解析できる実験系の確立を目指し、その第1歩としてワモンゴキブリとクロコオロギの匂い学習能力について調べた結果、どちらの昆虫も非常に高い匂い学習の能力があることが明らかになった。現在さらに、出力ニューロンと匂い記憶との解析を可能とするような匂い学習のパラダイムの開発を進めている。

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  • 行動システム制御科学特論
    開講年度 : 2020年
    課程区分 : 修士課程
    開講学部 : 生命科学院
    キーワード : 行動,脳,中枢神経系,社会性,コミュニケーション,認知,神経回路,ニューロン,最初期遺伝子,感覚情報処理,運動制御,学習,進化

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  • 2015年 - 現在   日本比較生理生化学会   評議員・編集委員
  • 2007年 - 2008年   日本比較生理生化学会   評議員   日本比較生理生化学会


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