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Sehadová H, Podlahová Š, Reppert SM, Sauman I. 3D reconstruction of larval and adult brain neuropils of two giant silk moth species: Hyalophora cecropia and Antheraea pernyi. JOURNAL OF INSECT PHYSIOLOGY 2023; 149:104546. [PMID: 37451537 DOI: 10.1016/j.jinsphys.2023.104546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 06/21/2023] [Accepted: 07/07/2023] [Indexed: 07/18/2023]
Abstract
We present a detailed analysis of the brain anatomy of two saturniid species, the cecropia silk moth, Hyalophora cecropia, and the Chinese oak silk moth, Antheraea pernyi, including 3D reconstructions of the major brain neuropils in the larva and in male and female adults. The 3D reconstructions, prepared from high-resolution optical sections, showed that the corresponding neuropils of these saturniid species are virtually identical. Similarities between the two species include a pronounced sexual dimorphism in the adults in the form of a male-specific assembly of markedly enlarged glomeruli forming the so-called macroglomerular complex. From the reports published to date, it can be concluded that the neuropil architecture of saturniids resembles that of other nocturnal moths, including the sibling family Sphingidae. In addition, compared with previous anatomical data on diurnal lepidopteran species, significant differences were observed in the two saturniid species, which include the thickness of the Y-tract of the mushroom body, the size of the main neuropils of the optic lobes, and the sexual dimorphisms of the antennal lobes.
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Affiliation(s)
- Hana Sehadová
- Biology Centre CAS, Institute of Entomology, Branisovska 31, 370 05 Ceske Budejovice, Czech Republic; University of South Bohemia in Ceske Budejovice, Faculty of Science, Branisovska 31, 370 05 Ceske Budejovice, Czech Republic.
| | - Šárka Podlahová
- Biology Centre CAS, Institute of Entomology, Branisovska 31, 370 05 Ceske Budejovice, Czech Republic; University of South Bohemia in Ceske Budejovice, Faculty of Science, Branisovska 31, 370 05 Ceske Budejovice, Czech Republic.
| | - Steven M Reppert
- Department of Neurobiology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01605, USA.
| | - Ivo Sauman
- Biology Centre CAS, Institute of Entomology, Branisovska 31, 370 05 Ceske Budejovice, Czech Republic; University of South Bohemia in Ceske Budejovice, Faculty of Science, Branisovska 31, 370 05 Ceske Budejovice, Czech Republic.
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2
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Kymre JH, Chu X, Ian E, Berg BG. Organization of the parallel antennal-lobe tracts in the moth. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2022; 208:707-721. [PMID: 36112200 PMCID: PMC9734247 DOI: 10.1007/s00359-022-01566-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 08/16/2022] [Accepted: 08/25/2022] [Indexed: 12/14/2022]
Abstract
The olfactory pathways of the insect brain have been studied comprehensively for more than 40 years, yet the last decade has included a particularly large accumulation of new information relating to this system's structure. In moths, sharp intracellular recording and staining has been used to elucidate the anatomy and physiology of output neurons from the primary olfactory center, the antennal lobe. This review concentrates on the connection patterns characterizing these projection neurons, which follow six separate antennal-lobe tracts. In addition to highlighting the connections between functionally distinct glomerular clusters and higher-order olfactory neuropils, we discuss how parallel tracts in the male convey distinct features of the social signals released by conspecific and heterospecific females. Finally, we consider the current state of knowledge regarding olfactory processing in the moth's protocerebrum and make suggestions as to how the information concerning antennal-lobe output may be used to design future studies.
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Affiliation(s)
- Jonas Hansen Kymre
- Chemosensory Lab, Department of Psychology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Xi Chu
- Chemosensory Lab, Department of Psychology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Elena Ian
- Chemosensory Lab, Department of Psychology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Bente Gunnveig Berg
- Chemosensory Lab, Department of Psychology, Norwegian University of Science and Technology, Trondheim, Norway
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3
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Massah A, Neupert S, Brodesser S, Homberg U, Stengl M. Distribution and daily oscillation of GABA in the circadian system of the cockroach Rhyparobia maderae. J Comp Neurol 2021; 530:770-791. [PMID: 34586642 DOI: 10.1002/cne.25244] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 09/06/2021] [Accepted: 09/09/2021] [Indexed: 12/28/2022]
Abstract
Gamma-aminobutyric acid (GABA) is the prevalent inhibitory neurotransmitter in nervous systems promoting sleep in both mammals and insects. In the Madeira cockroach, sleep-wake cycles are controlled by a circadian clock network in the brain's optic lobes, centered in the accessory medulla (AME) with its innervating pigment-dispersing factor (PDF) expressing clock neurons at the anterior-ventral rim of the medulla. GABA is present in cell clusters that innervate different circuits of the cockroach's AME clock, without colocalizing in PDF clock neurons. Physiological, immunohistochemical, and behavioral assays provided evidence for a role of GABA in light entrainment, possibly via the distal tract that connects the AME's glomeruli to the medulla. Furthermore, GABA was implemented in clock outputs to multiple effector systems in optic lobe and midbrain. Here, GABAergic brain circuits were analyzed further, focusing on the circadian system in search for sleep/wake controlling brain circuits. All GABA-immunoreactive neurons of the cockroach brain were also stained with an antiserum against the GABA-synthesizing enzyme glutamic acid decarboxylase. We found strong overlap of the distribution of GABA-immunoreactive networks with PDF clock networks in optic lobes and midbrain. Neurons in five of the six soma groups that innervate the clock exhibited GABA immunoreactivity. The intensity of GABA immunoreactivity in the distal tract showed daily fluctuations with maximum staining intensity in the middle of the day and weakest staining at the end of the day. Quantification via enzyme-linked immunosorbent assay and quantitative liquid chromatography coupled to electrospray ionization tandem mass spectrometry, likewise, showed higher GABA levels in the optic lobe during the inactivity phase of the cockroach during the day and lower levels during its activity phase at dusk. Our data further support the hypothesis that light- and PDF-dependently the circadian clock network of the cockroach controls GABA levels and thereby promotes sleep during the day.
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Affiliation(s)
- Azar Massah
- Institute of Biology, Animal Physiology, University of Kassel, Kassel, Germany
| | - Susanne Neupert
- Institute of Biology, Animal Physiology, University of Kassel, Kassel, Germany
| | - Susanne Brodesser
- Cluster of Excellence Cellular Stress Responses in Aging-Associated Diseases (CECAD), Faculty of Medicine and University Hospital of Cologne, University of Cologne, Cologne, Germany
| | - Uwe Homberg
- Department of Biology, Animal Physiology, Philipps-Universität Marburg, Marburg, Germany.,Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus Liebig University Giessen, Marburg, Germany
| | - Monika Stengl
- Institute of Biology, Animal Physiology, University of Kassel, Kassel, Germany
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4
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Kymre JH, Liu X, Ian E, Berge CN, Wang G, Berg BG, Zhao X, Chu X. Distinct protocerebral neuropils associated with attractive and aversive female-produced odorants in the male moth brain. eLife 2021; 10:65683. [PMID: 33988500 PMCID: PMC8154038 DOI: 10.7554/elife.65683] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 05/13/2021] [Indexed: 11/22/2022] Open
Abstract
The pheromone system of heliothine moths is an optimal model for studying principles underlying higher-order olfactory processing. In Helicoverpa armigera, three male-specific glomeruli receive input about three female-produced signals, the primary pheromone component, serving as an attractant, and two minor constituents, serving a dual function, that is, attraction versus inhibition of attraction. From the antennal-lobe glomeruli, the information is conveyed to higher olfactory centers, including the lateral protocerebrum, via three main paths – of which the medial tract is the most prominent. In this study, we traced physiologically identified medial-tract projection neurons from each of the three male-specific glomeruli with the aim of mapping their terminal branches in the lateral protocerebrum. Our data suggest that the neurons’ widespread projections are organized according to behavioral significance, including a spatial separation of signals representing attraction versus inhibition – however, with a unique capacity of switching behavioral consequence based on the amount of the minor components.
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Affiliation(s)
- Jonas Hansen Kymre
- Chemosensory lab, Department of Psychology, Norwegian University of Science and Technology, Trondheim, Norway
| | - XiaoLan Liu
- Department of Entomology, College of Plant Protection, Henan Agricultural University, Zhengzhou, China.,State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Elena Ian
- Chemosensory lab, Department of Psychology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Christoffer Nerland Berge
- Chemosensory lab, Department of Psychology, Norwegian University of Science and Technology, Trondheim, Norway
| | - GuiRong Wang
- State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Bente Gunnveig Berg
- Chemosensory lab, Department of Psychology, Norwegian University of Science and Technology, Trondheim, Norway
| | - XinCheng Zhao
- Department of Entomology, College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Xi Chu
- Chemosensory lab, Department of Psychology, Norwegian University of Science and Technology, Trondheim, Norway
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5
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Kymre JH, Berge CN, Chu X, Ian E, Berg BG. Antennal-lobe neurons in the moth Helicoverpa armigera: Morphological features of projection neurons, local interneurons, and centrifugal neurons. J Comp Neurol 2021; 529:1516-1540. [PMID: 32949023 PMCID: PMC8048870 DOI: 10.1002/cne.25034] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 09/02/2020] [Accepted: 09/07/2020] [Indexed: 01/11/2023]
Abstract
The relatively large primary olfactory center of the insect brain, the antennal lobe (AL), contains several heterogeneous neuronal types. These include projection neurons (PNs), providing olfactory information to higher‐order neuropils via parallel pathways, and local interneurons (LNs), which provide lateral processing within the AL. In addition, various types of centrifugal neurons (CNs) offer top‐down modulation onto the other AL neurons. By performing iontophoretic intracellular staining, we collected a large number of AL neurons in the moth, Helicoverpa armigera, to examine the distinct morphological features of PNs, LNs, and CNs. We characterize 190 AL neurons. These were allocated to 25 distinct neuronal types or sub‐types, which were reconstructed and placed into a reference brain. In addition to six PN types comprising 15 sub‐types, three LN and seven CN types were identified. High‐resolution confocal images allowed us to analyze AL innervations of the various reported neurons, which demonstrated that all PNs innervating ventroposterior glomeruli contact a protocerebral neuropil rarely targeted by other PNs, that is the posteriorlateral protocerebrum. We also discuss the functional roles of the distinct CNs, which included several previously uncharacterized types, likely involved in computations spanning from multisensory processing to olfactory feedback signalization into the AL.
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Affiliation(s)
- Jonas Hansen Kymre
- Chemosensory lab, Department of Psychology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Christoffer Nerland Berge
- Chemosensory lab, Department of Psychology, Norwegian University of Science and Technology, Trondheim, Norway.,Laboratory for Neural Computation, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Xi Chu
- Chemosensory lab, Department of Psychology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Elena Ian
- Chemosensory lab, Department of Psychology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Bente G Berg
- Chemosensory lab, Department of Psychology, Norwegian University of Science and Technology, Trondheim, Norway
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6
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Fuscà D, Kloppenburg P. Odor processing in the cockroach antennal lobe-the network components. Cell Tissue Res 2021; 383:59-73. [PMID: 33486607 PMCID: PMC7872951 DOI: 10.1007/s00441-020-03387-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 12/07/2020] [Indexed: 02/06/2023]
Abstract
Highly interconnected neural networks perform olfactory signal processing in the central nervous system. In insects, the first synaptic processing of the olfactory input from the antennae occurs in the antennal lobe, the functional equivalent of the olfactory bulb in vertebrates. Key components of the olfactory network in the antennal lobe are two main types of neurons: the local interneurons and the projection (output) neurons. Both neuron types have different physiological tasks during olfactory processing, which accordingly require specialized functional phenotypes. This review gives an overview of important cell type-specific functional properties of the different types of projection neurons and local interneurons in the antennal lobe of the cockroach Periplaneta americana, which is an experimental system that has elucidated many important biophysical and cellular bases of intrinsic physiological properties of these neurons.
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Affiliation(s)
- Debora Fuscà
- Biocenter, Institute for Zoology, and Cologne Excellence Cluster On Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Zülpicher Str. 47b, 50674, Cologne, Germany
| | - Peter Kloppenburg
- Biocenter, Institute for Zoology, and Cologne Excellence Cluster On Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Zülpicher Str. 47b, 50674, Cologne, Germany.
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7
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Neuronal architecture of the second-order CO 2 pathway in the brain of a noctuid moth. Sci Rep 2020; 10:19838. [PMID: 33199810 PMCID: PMC7669840 DOI: 10.1038/s41598-020-76918-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 11/04/2020] [Indexed: 12/17/2022] Open
Abstract
Many insects possess the ability to detect fine fluctuations in the environmental CO2 concentration. In herbivorous species, plant-emitted CO2, in combination with other sensory cues, affect many behaviors including foraging and oviposition. In contrast to the comprehensive knowledge obtained on the insect olfactory pathway in recent years, we still know little about the central CO2 system. By utilizing intracellular labeling and mass staining, we report the neuroanatomy of projection neurons connected with the CO2 sensitive antennal-lobe glomerulus, the labial pit organ glomerulus (LPOG), in the noctuid moth, Helicoverpa armigera. We identified 15 individual LPOG projection neurons passing along different tracts. Most of these uniglomerular neurons terminated in the lateral horn, a previously well-described target area of plant-odor projection neurons originating from the numerous ordinary antennal-lobe glomeruli. The other higher-order processing area for odor information, the calyces, on the other hand, was weakly innervated by the LPOG neurons. The overlapping LPOG terminals in the lateral horn, which is considered important for innate behavior in insects, suggests the biological importance of integrating the CO2 input with plant odor information while the weak innervation of the calyces indicates the insignificance of this ubiquitous cue for learning mechanisms.
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8
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Sizemore TR, Hurley LM, Dacks AM. Serotonergic modulation across sensory modalities. J Neurophysiol 2020; 123:2406-2425. [PMID: 32401124 PMCID: PMC7311732 DOI: 10.1152/jn.00034.2020] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 05/04/2020] [Accepted: 05/12/2020] [Indexed: 12/24/2022] Open
Abstract
The serotonergic system has been widely studied across animal taxa and different functional networks. This modulatory system is therefore well positioned to compare the consequences of neuromodulation for sensory processing across species and modalities at multiple levels of sensory organization. Serotonergic neurons that innervate sensory networks often bidirectionally exchange information with these networks but also receive input representative of motor events or motivational state. This convergence of information supports serotonin's capacity for contextualizing sensory information according to the animal's physiological state and external events. At the level of sensory circuitry, serotonin can have variable effects due to differential projections across specific sensory subregions, as well as differential serotonin receptor type expression within those subregions. Functionally, this infrastructure may gate or filter sensory inputs to emphasize specific stimulus features or select among different streams of information. The near-ubiquitous presence of serotonin and other neuromodulators within sensory regions, coupled with their strong effects on stimulus representation, suggests that these signaling pathways should be considered integral components of sensory systems.
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Affiliation(s)
- Tyler R Sizemore
- Department of Biology, West Virginia University, Morgantown, West Virginia
| | - Laura M Hurley
- Department of Biology, Indiana University, Bloomington, Indiana
| | - Andrew M Dacks
- Department of Biology, West Virginia University, Morgantown, West Virginia
- Department of Neuroscience, West Virginia University, Morgantown, West Virginia
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9
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Evolutionarily conserved anatomical and physiological properties of olfactory pathway through fourth-order neurons in a species of grasshopper (Hieroglyphus banian). J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2019; 205:813-838. [DOI: 10.1007/s00359-019-01369-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 08/08/2019] [Accepted: 09/04/2019] [Indexed: 01/18/2023]
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10
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Lee SG, Celestino CF, Stagg J, Kleineidam C, Vickers NJ. Moth pheromone-selective projection neurons with cell bodies in the antennal lobe lateral cluster exhibit diverse morphological and neurophysiological characteristics. J Comp Neurol 2019; 527:1443-1460. [PMID: 30723902 DOI: 10.1002/cne.24611] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 12/08/2018] [Accepted: 12/10/2018] [Indexed: 11/08/2022]
Abstract
Olfactory projection neurons convey information from the insect antennal lobe (AL) to higher brain centers. Previous reports have demonstrated that pheromone-responsive projection neurons with cell bodies in the moth medial cell cluster (mcPNs) predominantly have dendritic arborizations in the sexually dimorphic macroglomerular complex (MGC) and send an axon from the AL to the calyces of the mushroom body (CA) as well as the lateral horn (LH) of the protocerebrum via the medial AL tract. These neurons typically exhibit a narrow odor tuning range related to the restriction of their dendritic arbors within a single glomerulus (uniglomerular). In this study, we report on the diverse physiological and morphological properties of a group of pheromone-responsive olfactory projection neurons with cell bodies in the AL lateral cell cluster (MGC lcPNs) of two closely related moth species. All pheromone-responsive lcPNs appeared to exhibit "basket-like" dendritic arborizations in two MGC compartments and made connections with various protocerebral targets including ventrolateral and superior neuropils via projections primarily through the lateral AL tract and to a lesser extent the mediolateral antennal lobe tract. Physiological characterization of MGC lcPNs also revealed a diversity of response profiles including those either enhanced by or reliant upon presentation of a pheromone blend. These responses manifested themselves as higher maximum firing rates and/or improved temporal resolution of pulsatile stimuli. MGC lcPNs therefore participate in conveying diverse olfactory information relating to qualitative and temporal facets of the pheromone stimulus to a more expansive number of protocerebral targets than their mcPN counterparts.
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Affiliation(s)
- Seong-Gyu Lee
- School of Biological Sciences, University of Utah, Salt Lake City, Utah
| | - Christine Fogarty Celestino
- School of Biological Sciences, University of Utah, Salt Lake City, Utah.,Program in Neuroscience, University of Utah, Salt Lake City, Utah
| | - Jeffrey Stagg
- School of Biological Sciences, University of Utah, Salt Lake City, Utah
| | | | - Neil J Vickers
- School of Biological Sciences, University of Utah, Salt Lake City, Utah
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11
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First assessment of the comparative toxicity of ivermectin and moxidectin in adult dung beetles: Sub-lethal symptoms and pre-lethal consequences. Sci Rep 2018; 8:14885. [PMID: 30291291 PMCID: PMC6173729 DOI: 10.1038/s41598-018-33241-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 09/20/2018] [Indexed: 11/27/2022] Open
Abstract
Among macrocyclic lactones (ML), ivermectin (IVM) and moxidectin (MOX) potentially affect all Ecdysozoan species, with dung beetles being particularly sensitive. The comparative effects of IVM and MOX on adult dung beetles were assessed for the first time to determine both the physiological sub-lethal symptoms and pre-lethal consequences. Inhibition of antennal response and ataxia were tested as two intuitive and ecologically relevant parameters by obtaining the lowest observed effect concentration (LOEC) values and interpolating other relevant toxicity thresholds derived from concentration-response curves (IC50, as the concentration of each ML where the antennal response is inhibited by half; and pLC50, as the quantity of ingested ML where partial paralysis was observed by half of treated individuals) from concentration-response curves. Both sub-lethal and pre-lethal symptoms obtained in this study coincided in that IVM was six times more toxic than MOX for adult dung beetles. Values of LOEC, IC50 and pLC50 obtained for IVM and MOX evaluated in an environmental context indicate that MOX, despite needing more time for its elimination in the faeces, would be half as harmful to dung beetles as IVM. This approach will be valuable to clarify the real impact of MLs on dung beetle health and to avoid the subsequent environmental consequences.
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12
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Fabian-Fine R, Anderson CM, Roush MA, Johnson JAG, Liu H, French AS, Torkkeli PH. The distribution of cholinergic neurons and their co-localization with FMRFamide, in central and peripheral neurons of the spider Cupiennius salei. Cell Tissue Res 2017; 370:71-88. [PMID: 28687927 DOI: 10.1007/s00441-017-2652-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 05/23/2017] [Indexed: 12/21/2022]
Abstract
The spider Cupiennius salei is a well-established model for investigating information processing in arthropod sensory systems. Immunohistochemistry has shown that several neurotransmitters exist in the C. salei nervous system, including GABA, glutamate, histamine, octopamine and FMRFamide, while electrophysiology has found functional roles for some of these transmitters. There is also evidence that acetylcholine (ACh) is present in some C. salei neurons but information about the distribution of cholinergic neurons in spider nervous systems is limited. Here, we identify C. salei genes that encode enzymes essential for cholinergic transmission: choline ACh transferase (ChAT) and vesicular ACh transporter (VAChT). We used in-situ hybridization with an mRNA probe for C. salei ChAT gene to locate somata of cholinergic neurons in the central nervous system and immunohistochemistry with antisera against ChAT and VAChT to locate these proteins in cholinergic neurons. All three markers labeled similar, mostly small neurons, plus a few mid-sized neurons, in most ganglia. In the subesophageal ganglia, labeled neurons are putative efferent, motor or interneurons but the largest motor and interneurons were unlabeled. Groups of anti-ChAT labeled small neurons also connect the optic neuropils in the spider protocerebrum. Differences in individual cell labeling intensities were common, suggesting a range of ACh expression levels. Double-labeling found a subpopulation of anti-VAChT-labeled central and mechanosensory neurons that were also immunoreactive to antiserum against FMRFamide-like peptides. Our findings suggest that ACh is an important neurotransmitter in the C. salei central and peripheral nervous systems.
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Affiliation(s)
- Ruth Fabian-Fine
- Department of Biology, Saint Michael's College, One Winooski Park, Box 283, Colchester, VT, 05439, USA.
| | - Carly M Anderson
- Department of Biology, Saint Michael's College, One Winooski Park, Box 283, Colchester, VT, 05439, USA
| | - Molly A Roush
- Department of Biology, Saint Michael's College, One Winooski Park, Box 283, Colchester, VT, 05439, USA
| | - Jessica A G Johnson
- Department of Physiology and Biophysics, Dalhousie University, PO Box 15000, Halifax, NS, B3H 4R2, Canada
| | - Hongxia Liu
- Department of Physiology and Biophysics, Dalhousie University, PO Box 15000, Halifax, NS, B3H 4R2, Canada
| | - Andrew S French
- Department of Physiology and Biophysics, Dalhousie University, PO Box 15000, Halifax, NS, B3H 4R2, Canada
| | - Päivi H Torkkeli
- Department of Physiology and Biophysics, Dalhousie University, PO Box 15000, Halifax, NS, B3H 4R2, Canada
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13
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Ian E, Kirkerud NH, Galizia CG, Berg BG. Coincidence of pheromone and plant odor leads to sensory plasticity in the heliothine olfactory system. PLoS One 2017; 12:e0175513. [PMID: 28467500 PMCID: PMC5414983 DOI: 10.1371/journal.pone.0175513] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Accepted: 03/27/2017] [Indexed: 11/18/2022] Open
Abstract
Male moths possess a highly specialized olfactory system comprised of two segregated sub-arrangements dedicated to processing information about plant odors and pheromones, respectively. Communication between these two sub-systems has been described at the peripheral level, but relatively little is known about putative interactions at subsequent synaptic relays. The male moth faces the challenge of seeking out the conspecific female in a highly dynamic odor world. The female-produced pheromone blend, which is a limited resource serving as guidance for the male, will reach his antennae in intermittent pockets of odor filaments mixed with volatiles from various plants. In the present study we performed calcium imaging for measuring odor-evoked responses in the uni-glomerular antennal-lobe projection neurons (analog to mitral cells in the vertebrate olfactory bulb) of Helicoverpa armigera. In order to investigate putative interactions between the two sub-systems tuned to plant volatiles and pheromones, respectively, we performed repeated stimulations with a selection of biologically relevant odors. We found that paired stimulation with a plant odor and the pheromone led to suppressed responses in both sub-systems as compared to those evoked during initial stimulation including application of each odor stimulus alone. The fact that the suppression persisted also after pairing, indicates the existence of a Hebbian-like plasticity in the primary olfactory center established by temporal pairing of the two odor stimulation categories.
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Affiliation(s)
- Elena Ian
- Norwegian University of Science and Technology (NTNU), Department of Psychology, Trondheim, Norway
| | - Nicholas H. Kirkerud
- Norwegian University of Science and Technology (NTNU), Department of Psychology, Trondheim, Norway
- Universität Konstanz Fachbereich Biologie, Konstanz, Germany
| | | | - Bente G. Berg
- Norwegian University of Science and Technology (NTNU), Department of Psychology, Trondheim, Norway
- * E-mail:
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14
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Ian E, Zhao XC, Lande A, Berg BG. Individual Neurons Confined to Distinct Antennal-Lobe Tracts in the Heliothine Moth: Morphological Characteristics and Global Projection Patterns. Front Neuroanat 2016; 10:101. [PMID: 27822181 PMCID: PMC5075568 DOI: 10.3389/fnana.2016.00101] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 10/05/2016] [Indexed: 11/13/2022] Open
Abstract
To explore fundamental principles characterizing chemosensory information processing, we have identified antennal-lobe projection neurons in the heliothine moth, including several neuron types not previously described. Generally, odor information is conveyed from the primary olfactory center of the moth brain, the antennal lobe, to higher brain centers via projection neuron axons passing along several parallel pathways, of which the medial, mediolateral, and lateral antennal-lobe tract are considered the classical ones. Recent data have revealed the projections of the individual tracts more in detail demonstrating three main target regions in the protocerebrum; the calyces are innervated mainly by the medial tract, the superior intermediate protocerebrum by the lateral tract exclusively, and the lateral horn by all tracts. In the present study, we have identified, via iontophoretic intracellular staining combined with confocal microscopy, individual projection neurons confined to the tracts mentioned above, plus two additional ones. Further, using the visualization software AMIRA, we reconstructed the stained neurons and registered the models into a standard brain atlas, which allowed us to compare the termination areas of individual projection neurons both across and within distinct tracts. The data demonstrate a morphological diversity of the projection neurons within distinct tracts. Comparison of the output areas of the neurons confined to the three main tracts in the lateral horn showed overlapping terminal regions for the medial and mediolateral tracts; the lateral tract neurons, on the contrary, targeted mostly other output areas in the protocerebrum.
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Affiliation(s)
- Elena Ian
- Department of Psychology, Norwegian University of Science and Technology Trondheim, Norway
| | - Xin C Zhao
- Department of Entomology, College of Plant Protection, Henan Agricultural University Zhengzhou, China
| | - Andreas Lande
- Department of Psychology, Norwegian University of Science and Technology Trondheim, Norway
| | - Bente G Berg
- Department of Psychology, Norwegian University of Science and Technology Trondheim, Norway
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Antennal-lobe tracts in the noctuid moth, Heliothis virescens: new anatomical findings. Cell Tissue Res 2016; 366:23-35. [PMID: 27352608 DOI: 10.1007/s00441-016-2448-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 05/17/2016] [Indexed: 10/21/2022]
Abstract
As in other insects, three main tracts in the moth brain form parallel connections between the antennal lobe and the protocerebrum. These tracts, which consist of the antennal-lobe projection-neuron axons, target two main areas in the protocerebrum, the calyces of the mushroom bodies and the lateral horn. In spite of the solid neuroanatomical knowledge already established, there are still unresolved issues regarding the antennal-lobe tracts of the moth. One is the proportion of lateral-tract neurons targeting the calyces. In the study presented here, we have performed both retrograde and anterograde labeling of the antennal-lobe projection neurons in the brain of the moth, Heliothis virescens. The results from the retrograde staining, obtained by applying dye in the calyces, demonstrated that the direct connection between the antennal lobe and this neuropil is maintained primarily by the medial antennal-lobe tract; only a few axons confined to the lateral tract were found to innervate the calyces. In addition, these staining experiments, which allowed us to explore the arborization pattern of labeled neurons within the antennal lobe, resulted in new findings regarding anatomical arrangement of roots and cell body clusters linked to the medial tract. The results from the anterograde staining, obtained by applying dye into the antennal lobe, visualized the total assembly of axons passing along the antennal-lobe tracts. In addition to the three classical tracts, we found a transverse antennal-lobe tract not previously described in the moth. Also, these staining experiments revealed an organized neuropil in the lateral horn formed by terminals of the four antennal-lobe tracts.
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Zhao XC, Chen QY, Guo P, Xie GY, Tang QB, Guo XR, Berg BG. Glomerular identification in the antennal lobe of the male mothHelicoverpa armigera. J Comp Neurol 2016; 524:2993-3013. [DOI: 10.1002/cne.24003] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 03/16/2016] [Accepted: 03/24/2016] [Indexed: 01/02/2023]
Affiliation(s)
- Xin-Cheng Zhao
- Department of Entomology, College of Plant Protection; Henan Agricultural University; Zhengzhou 450002 China
| | - Qiu-Yan Chen
- Department of Entomology, College of Plant Protection; Henan Agricultural University; Zhengzhou 450002 China
| | - Pei Guo
- Department of Entomology, College of Plant Protection; Henan Agricultural University; Zhengzhou 450002 China
| | - Gui-Ying Xie
- Department of Entomology, College of Plant Protection; Henan Agricultural University; Zhengzhou 450002 China
| | - Qing-Bo Tang
- Department of Entomology, College of Plant Protection; Henan Agricultural University; Zhengzhou 450002 China
| | - Xian-Ru Guo
- Department of Entomology, College of Plant Protection; Henan Agricultural University; Zhengzhou 450002 China
- Collaborative Innovation Center of Henan Grain Crops; Zhengzhou 450002 China
| | - Bente G. Berg
- Department of Psychology; Norwegian University of Science and Technology; Trondheim 7489 Norway
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Kollmann M, Rupenthal AL, Neumann P, Huetteroth W, Schachtner J. Novel antennal lobe substructures revealed in the small hive beetle Aethina tumida. Cell Tissue Res 2015; 363:679-92. [PMID: 26496732 DOI: 10.1007/s00441-015-2282-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2015] [Accepted: 08/17/2015] [Indexed: 12/28/2022]
Abstract
The small hive beetle, Aethina tumida, is an emerging pest of social bee colonies. A. tumida shows a specialized life style for which olfaction seems to play a crucial role. To better understand the olfactory system of the beetle, we used immunohistochemistry and 3-D reconstruction to analyze brain structures, especially the paired antennal lobes (AL), which represent the first integration centers for odor information in the insect brain. The basic neuroarchitecture of the A. tumida brain compares well to the typical beetle and insect brain. In comparison to other insects, the AL are relatively large in relationship to other brain areas, suggesting that olfaction is of major importance for the beetle. The AL of both sexes contain about 70 olfactory glomeruli with no obvious size differences of the glomeruli between sexes. Similar to all other insects including beetles, immunostaining with an antiserum against serotonin revealed a large cell that projects from one AL to the contralateral AL to densely innervate all glomeruli. Immunostaining with an antiserum against tachykinin-related peptides (TKRP) revealed hitherto unknown structures in the AL. Small TKRP-immunoreactive spherical substructures are in both sexes evenly distributed within all glomeruli. The source for these immunoreactive islets is very likely a group of about 80 local AL interneurons. We offer two hypotheses on the function of such structures.
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Affiliation(s)
- Martin Kollmann
- Department of Biology, Animal Physiology, Philipps-University Marburg, Karl-von-Frisch-Str. 8, 35032, Marburg, Germany
| | - Anna Lena Rupenthal
- Department of Biology, Animal Physiology, Philipps-University Marburg, Karl-von-Frisch-Str. 8, 35032, Marburg, Germany
| | - Peter Neumann
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Wolf Huetteroth
- Department of Biology, Animal Physiology, Philipps-University Marburg, Karl-von-Frisch-Str. 8, 35032, Marburg, Germany.,Department of Biology, Neurobiology, University of Konstanz, 78457, Konstanz, Germany
| | - Joachim Schachtner
- Department of Biology, Animal Physiology, Philipps-University Marburg, Karl-von-Frisch-Str. 8, 35032, Marburg, Germany.
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Tabuchi M, Dong L, Inoue S, Namiki S, Sakurai T, Nakatani K, Kanzaki R. Two types of local interneurons are distinguished by morphology, intrinsic membrane properties, and functional connectivity in the moth antennal lobe. J Neurophysiol 2015; 114:3002-13. [PMID: 26378200 DOI: 10.1152/jn.00050.2015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 09/15/2015] [Indexed: 11/22/2022] Open
Abstract
Neurons in the silkmoth antennal lobe (AL) are well characterized in terms of their morphology and odor-evoked firing activity. However, their intrinsic electrical properties including voltage-gated ionic currents and synaptic connectivity remain unclear. To address this, whole cell current- and voltage-clamp recordings were made from second-order projection neurons (PNs) and two morphological types of local interneurons (LNs) in the silkmoth AL. The two morphological types of LNs exhibited distinct physiological properties. One morphological type of LN showed a spiking response with a voltage-gated sodium channel gene expression, whereas the other type of LN was nonspiking without a voltage-gated sodium channel gene expression. Voltage-clamp experiments also revealed that both of two types of LNs as well as PNs possessed two types of voltage-gated potassium channels and calcium channels. In dual whole cell recordings of spiking LNs and PNs, activation of the PN elicited depolarization responses in the paired spiking LN, whereas activation of the spiking LN induced no substantial responses in the paired PN. However, simultaneous recording of a nonspiking LN and a PN showed that activation of the nonspiking LN induced hyperpolarization responses in the PN. We also observed bidirectional synaptic transmission via both chemical and electrical coupling in the pairs of spiking LNs. Thus our results indicate that there were two distinct types of LNs in the silkmoth AL, and their functional connectivity to PNs was substantially different. We propose distinct functional roles for these two different types of LNs in shaping odor-evoked firing activity in PNs.
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Affiliation(s)
- Masashi Tabuchi
- Department of Advanced Interdisciplinary Studies, Graduate School of Engineering, The University of Tokyo, Meguro-ku, Tokyo, Japan; Research Center for Advanced Science and Technology, The University of Tokyo, Meguro-ku, Tokyo, Japan
| | - Li Dong
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan; and
| | - Shigeki Inoue
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan; and
| | - Shigehiro Namiki
- Research Center for Advanced Science and Technology, The University of Tokyo, Meguro-ku, Tokyo, Japan
| | - Takeshi Sakurai
- Research Center for Advanced Science and Technology, The University of Tokyo, Meguro-ku, Tokyo, Japan
| | - Kei Nakatani
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan; and
| | - Ryohei Kanzaki
- Research Center for Advanced Science and Technology, The University of Tokyo, Meguro-ku, Tokyo, Japan
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Low doses of ivermectin cause sensory and locomotor disorders in dung beetles. Sci Rep 2015; 5:13912. [PMID: 26350768 PMCID: PMC4563563 DOI: 10.1038/srep13912] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 08/07/2015] [Indexed: 01/19/2023] Open
Abstract
Ivermectin is a veterinary pharmaceutical generally used to control the ecto- and endoparasites of livestock, but its use has resulted in adverse effects on coprophilous insects, causing population decline and biodiversity loss. There is currently no information regarding the direct effects of ivermectin on dung beetle physiology and behaviour. Here, based on electroantennography and spontaneous muscle force tests, we show sub-lethal disorders caused by ivermectin in sensory and locomotor systems of Scarabaeus cicatricosus, a key dung beetle species in Mediterranean ecosystems. Our findings show that ivermectin decreases the olfactory and locomotor capacity of dung beetles, preventing them from performing basic biological activities. These effects are observed at concentrations lower than those usually measured in the dung of treated livestock. Taking into account that ivermectin acts on both glutamate-gated and GABA-gated chloride ion channels of nerve and muscle cells, we predict that ivermectin’s effects at the physiological level could influence many members of the dung pat community. The results indicate that the decline of dung beetle populations could be related to the harmful effects of chemical contamination in the dung.
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Fusca D, Schachtner J, Kloppenburg P. Colocalization of allatotropin and tachykinin-related peptides with classical transmitters in physiologically distinct subtypes of olfactory local interneurons in the cockroach (Periplaneta americana). J Comp Neurol 2015; 523:1569-86. [PMID: 25678036 DOI: 10.1002/cne.23757] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Revised: 01/28/2015] [Accepted: 02/03/2015] [Indexed: 11/06/2022]
Abstract
In the insect antennal lobe different types of local interneurons mediate complex excitatory and inhibitory interactions between the glomerular pathways to structure the spatiotemporal representation of odors. Mass spectrometric and immunohistochemical studies have shown that in local interneurons classical neurotransmitters are likely to colocalize with a variety of substances that can potentially act as cotransmitters or neuromodulators. In the antennal lobe of the cockroach Periplaneta americana, gamma-aminobutyric acid (GABA) has been identified as the potential inhibitory transmitter of spiking type I local interneurons, whereas acetylcholine is most likely the excitatory transmitter of nonspiking type IIa1 local interneurons. This study used whole-cell patch clamp recordings combined with single-cell labeling and immunohistochemistry to test if the GABAergic type I local interneurons and the cholinergic type IIa1 local interneurons express allatotropin and tachykinin-related neuropeptides (TKRPs). These are two of the most abundant types of peptides in the insect antennal lobe. GABA-like and choline acetyltransferase (ChAT)-like immunoreactivity were used as markers for GABAergic and cholinergic neurons, respectively. About 50% of the GABA-like immunoreactive (-lir) spiking type I local interneurons were allatotropin-lir, and ∼ 40% of these neurons were TKRP-lir. About 20% of nonspiking ChAT-lir type IIa1 local interneurons were TKRP-lir. Our results suggest that in subpopulations of GABAergic and cholinergic local interneurons, allatotropin and TKRPs might act as cotransmitters or neuromodulators. To unequivocally assign neurotransmitters, cotransmitters, and neuromodulators to identified classes of antennal lobe neurons is an important step to deepen our understanding of information processing in the insect olfactory system.
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Affiliation(s)
- Debora Fusca
- Biocenter, Institute for Zoology, and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | | | - Peter Kloppenburg
- Biocenter, Institute for Zoology, and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
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Kromann SH, Hansson BS, Ignell R. Distribution of neuropeptides in the antennal lobes of male Spodoptera littoralis. Cell Tissue Res 2013; 354:431-40. [PMID: 23955643 DOI: 10.1007/s00441-013-1703-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Accepted: 07/10/2013] [Indexed: 10/26/2022]
Abstract
Olfaction is an important sensory modality that regulates a plethora of behavioural expressions in insects. Processing of olfactory information takes place in the primary olfactory centres of the brain, namely the antennal lobes (ALs). Neuropeptides have been shown to be present in the olfactory system of various insect species. In the present study, we analyse the distribution of tachykinin, FMRFamide-related peptides, allatotropin, allatostatin, myoinhibitory peptides and SIFamide in the AL of the male Egyptian cotton leafworm, Spodoptera littoralis. Immunocytochemical analyses revealed that most neuropeptides were expressed in different subpopulations of AL neurons. Their arborisation patterns within the AL suggest a significant role of neuropeptide signalling in the modulation of AL processing. In addition to local interneurons, our analysis also revealed a diversity of extrinsic peptidergic neurons that connected the antennal lobe with other brain centres. Their distributions suggest that extrinsic neurons perform various types of context-related modulation.
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Affiliation(s)
- Sophie H Kromann
- Department of Plant Protection Biology, Unit of Chemical Ecology, Swedish University of Agricultural Sciences, Box 102, 230 53, Alnarp, Sweden,
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Pregitzer P, Schultze A, Raming K, Breer H, Krieger J. Expression of a GABA(B) - receptor in olfactory sensory neurons of sensilla trichodea on the male antenna of the moth Heliothis virescens. Int J Biol Sci 2013; 9:707-15. [PMID: 23904795 PMCID: PMC3729013 DOI: 10.7150/ijbs.6674] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 06/23/2013] [Indexed: 12/03/2022] Open
Abstract
In the olfactory pathway of Drosophila, a GABAB receptor mediated presynaptic gain control mechanism at the first synapse between olfactory sensory neurons (OSNs) and projection neurons has been suggested to play a critical role in setting the sensitivity and detection range of the sensory system. To approach the question if such a mechanism may be realized in the pheromone recognition system of male moths in this study attempts were made to explore if moth's pheromone-responsive cells express a GABAB- receptor. Employing a combination of genome analysis, RT-PCR experiments and screening of an antennal cDNA library we have identified a cDNA which encodes the GABAB-R1 receptor of Heliothis virescens. Moreover, based on the HvirGABAB-R1 sequence we could predict a GABAB-R1 protein from genome sequences of the silkmoth Bombyx mori. To assess whether HvirGABAB-R1 is expressed in OSNs of male antenna we performed whole-mount in situ hybridization (WM-ISH) experiments. Several HvirGABAB-R1 positive cells were visualized under long sensilla trichodea, known to contain pheromone-responsive OSNs. In parallel it was shown that cells under long trichoid hairs were labelled with pheromone receptor specific probes. In addition, the HvirGABAB-R1 specific probe also labelled several cells under shorter olfactory sensilla, but never stained cells under mechanosensory/gustatory sensilla chaetica. Together, the results indicate that a GABAB receptor is expressed in pheromone-responsive OSNs of H. virescens and suggest a presynaptic gain control mechanism in the axon terminals of these cells.
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Affiliation(s)
- Pablo Pregitzer
- University of Hohenheim, Institute of Physiology, Stuttgart, Germany
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Kruangkum T, Chotwiwatthanakun C, Vanichviriyakit R, Tinikul Y, Anuracpreeda P, Wanichanon C, Hanna PJ, Sobhon P. Structure of the olfactory receptor organs, their GABAergic neural pathways, and modulation of mating behavior, in the giant freshwater prawn, Macrobrachium rosenbergii. Microsc Res Tech 2013; 76:572-87. [PMID: 23495186 DOI: 10.1002/jemt.22202] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Revised: 02/05/2013] [Accepted: 02/08/2013] [Indexed: 12/24/2022]
Abstract
In the giant male prawn, Macrobrachium rosenbergii, the olfactory system is thought to be the main pathway for modulating sexual behavior through pheromone perception. In this report, we first used gross anatomical, histological, and SEM methods to describe the structures of the olfactory receptors (sensilla setae), their neural pathways, and possible role in modulating mating behavior. On the surfaces of antennule and antenna filaments there are four types of sensory receptors, viz single spike-like setae, single flagellum-like setae, multiple flagella-like setae, and aesthetascs (ASs). The ASs, which had previously been proposed to be odor receptor setae, are found only on the short filament of lateral antennule (slAn). Each AS on the slAn connects with olfactory receptor neurons (ORNs), whose axons form an outer central antennule nerve (ocAnNv), which then connects with the olfactory neutrophil (ON) of the brain. Thus, the slAn is the major olfactory organ that conveys sensory inputs from each AS to the ON within the deutocerebrum. GABA immunoreactivity was present in ASs, neurons of ORNs, inner central antennular, lateral tegumentary nerve, ocAnNv and the ON, inferring that GABA is the likely neurotransmitter in modulating olfaction. Disruption of the slAn by ablation or covering with Vaseline, resulted in significant reduction of mating behavior, indicating that this organ is crucial for sex pheromone perception. Identification of the active pheromones and further bioassays are now being performed.
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Affiliation(s)
- Thanapong Kruangkum
- Department of Anatomy, Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand
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Løfaldli BB, Kvello P, Kirkerud N, Mustaparta H. Activity in Neurons of a Putative Protocerebral Circuit Representing Information about a 10 Component Plant Odor Blend in Heliothis virescens. Front Syst Neurosci 2012; 6:64. [PMID: 23060753 PMCID: PMC3461648 DOI: 10.3389/fnsys.2012.00064] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Accepted: 08/21/2012] [Indexed: 11/24/2022] Open
Abstract
The olfactory pathway in the insect brain is anatomically well described from the antennal lobe (AL) to the mushroom bodies and the lateral protocerebrum (LP) in several species. Less is known about the further connections of the olfactory network in protocerebrum and how information about relevant plant odorants and mixtures are represented in this network, resulting in output information mediated by descending neurons. In the present study we have recorded intracellularly followed by dye injections from neurons in the LP and superior protocerebrum (SP) of the moth, Heliothis virescens. As relevant stimuli, we have used selected primary plant odorants and mixtures of them. The results provide the morphology and physiological responses of neurons involved in a putative circuit connecting the mushroom body lobes, the SP, and the LP, as well as input to SP and LP by one multiglomerular AL neuron and output from the LP by one descending neuron. All neurons responded to a particular mixture of ten primary plant odorants, some of them also to single odorants of the mixture. Altogether, the physiological data indicate integration in protocerebral neurons of information from several of the receptor neuron types functionally described in this species.
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Affiliation(s)
- Bjarte Bye Løfaldli
- Neuroscience Unit, Department of Biology, Norwegian University of Science and Technology Trondheim, Norway
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25
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Anatomical basis of sun compass navigation I: The general layout of the monarch butterfly brain. J Comp Neurol 2012; 520:1599-628. [DOI: 10.1002/cne.23054] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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26
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Neupert S, Fusca D, Schachtner J, Kloppenburg P, Predel R. Toward a single-cell-based analysis of neuropeptide expression in Periplaneta americana antennal lobe neurons. J Comp Neurol 2012; 520:694-716. [DOI: 10.1002/cne.22745] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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27
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Missbach C, Harzsch S, Hansson BS. New insights into an ancient insect nose: the olfactory pathway of Lepismachilis y-signata (Archaeognatha: Machilidae). ARTHROPOD STRUCTURE & DEVELOPMENT 2011; 40:317-333. [PMID: 21665539 DOI: 10.1016/j.asd.2011.03.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2010] [Revised: 03/07/2011] [Accepted: 03/30/2011] [Indexed: 05/30/2023]
Abstract
Hexapods most likely derived from an aquatic ancestor, which they shared with crustaceans. During the transition from water to land, their sensory systems had to face the new physiological demands that terrestrial conditions impose. This process also concerns the sense of smell and, more specifically, detection of volatile, air-borne chemicals. In insects, olfaction plays an important role in orientation, mating choice, and food and host finding behavior. The first integration center of odor information in the insect brain is the antennal lobe, which is targeted by the afferents from olfactory sensory neurons on the antennae. Within the antennal lobe of most pterygote insects, spherical substructures called olfactory glomeruli are present. In order to gain insights into the evolution of the structure of the central olfactory pathway in insects, we analyzed a representative of the wingless Archaeognatha or jumping bristletails, using immunocytochemistry, antennal backfills and histological section series combined with 3D reconstruction. In the deutocerebrum of Lepismachilis y-signata, we found three different neuropil regions. Two of them show a glomerular organization, but these glomeruli differ in their shape from those in all other insect groups. The connection of the glomerular neuropils to higher brain centers remains unclear and mushroom bodies are absent as reported from other archaeognathan species. We discuss the evolutionary implications of these findings.
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Affiliation(s)
- Christine Missbach
- Max-Planck-Institute for Chemical Ecology, Department of Neuroethology, Hans-Knöll-Strasse 8, D-07745 Jena, Germany.
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Reisenman CE, Dacks AM, Hildebrand JG. Local interneuron diversity in the primary olfactory center of the moth Manduca sexta. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2011; 197:653-65. [PMID: 21286727 DOI: 10.1007/s00359-011-0625-x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Revised: 01/10/2011] [Accepted: 01/15/2011] [Indexed: 02/06/2023]
Abstract
Local interneurons (LNs) play important roles in shaping and modulating the activity of output neurons in primary olfactory centers. Here, we studied the morphological characteristics, odor responses, and neurotransmitter content of LNs in the antennal lobe (AL, the insect primary olfactory center) of the moth Manduca sexta. We found that most LNs are broadly tuned, with all LNs responding to at least one odorant. 70% of the odorants evoked a response, and 22% of the neurons responded to all the odorants tested. Some LNs showed excitatory (35%) or inhibitory (33%) responses only, while 33% of the neurons showed both excitatory and inhibitory responses, depending on the odorant. LNs that only showed inhibitory responses were the most responsive, with 78% of the odorants evoking a response. Neurons were morphologically diverse, with most LNs innervating almost all glomeruli and others innervating restricted portions of the AL. 61 and 39% of LNs were identified as GABA-immunoreactive (GABA-ir) and non-GABA-ir, respectively. We found no correlations between odor responses and GABA-ir, neither between morphology and GABA-ir. These results show that, as observed in other insects, LNs are diverse, which likely determines the complexity of the inhibitory network that regulates AL output.
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Dacks AM, Nighorn AJ. The organization of the antennal lobe correlates not only with phylogenetic relationship, but also life history: a Basal hymenopteran as exemplar. Chem Senses 2010; 36:209-20. [PMID: 21059697 DOI: 10.1093/chemse/bjq121] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The structure of the brain is a consequence of selective pressures and the ancestral brain structures modified by those pressures. The Hymenoptera are one of the most behaviorally complex insect orders, and the olfactory system of honeybees (one of the most derived members) has been extensively studied. To understand the context in which the olfactory system of the Hymenoptera evolved, we performed a variety of immunocytochemical and anatomical labeling techniques on the antennal lobes (ALs) of one of its most primitive members, the sawflies, to provide a comparison between the honeybee and other insect model species. The olfactory receptor neurons project from the antennae to fill the entire glomerular volume but do not form distinct tracts as in the honeybee. Labeling of projection neurons revealed 5 output tracts similar to those in moths and immunolabeling for several transmitters revealed distinct populations of local interneurons and centrifugal neurons that were also similar to moths. There were, however, no histaminergic or dopaminergic AL neurons. The similarities between sawflies and moths suggest that along with the great radiation and increased complexity of behavioral repertoire of the Hymenoptera, there were extensive modifications of AL structure.
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Affiliation(s)
- Andrew M Dacks
- Department of Neuroscience, The University of Arizona, 1040 East 4th Street, Tucson, AZ 85721, USA.
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Carlsson MA, Diesner M, Schachtner J, Nässel DR. Multiple neuropeptides in the Drosophila antennal lobe suggest complex modulatory circuits. J Comp Neurol 2010; 518:3359-80. [PMID: 20575072 DOI: 10.1002/cne.22405] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The fruitfly, Drosophila, is dependent on its olfactory sense in food search and reproduction. Processing of odorant information takes place in the antennal lobes, the primary olfactory center in the insect brain. Besides classical neurotransmitters, earlier studies have indicated the presence of a few neuropeptides in the olfactory system. In the present study we made an extensive analysis of the expression of neuropeptides in the Drosophila antennal lobes by direct profiling using matrix-assisted laser desorption/ionization-time-of-flight (MALDI-TOF) mass spectrometry and immunocytochemistry. Neuropeptides from seven different precursor genes were unambiguously identified and their localization in neurons was subsequently revealed by immunocytochemistry. These were short neuropeptide F, tachykinin related peptide, allatostatin A, myoinhibitory peptide, SIFamide, IPNamide, and myosuppressin. The neuropeptides were expressed in subsets of olfactory sensory cells and different populations of local interneurons and extrinsic (centrifugal) neurons. In some neuron types neuropeptides were colocalized with classical neurotransmitters. Our findings suggest a huge complexity in peptidergic signaling in different circuits of the antennal lobe.
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Affiliation(s)
- Mikael A Carlsson
- Department of Zoology, Stockholm University, S-10691, Stockholm, Sweden.
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Sombke A, Harzsch S, Hansson BS. Organization of Deutocerebral Neuropils and Olfactory Behavior in the Centipede Scutigera coleoptrata (Linnaeus, 1758) (Myriapoda: Chilopoda). Chem Senses 2010; 36:43-61. [DOI: 10.1093/chemse/bjq096] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
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Krieger J, Sandeman RE, Sandeman DC, Hansson BS, Harzsch S. Brain architecture of the largest living land arthropod, the Giant Robber Crab Birgus latro (Crustacea, Anomura, Coenobitidae): evidence for a prominent central olfactory pathway? Front Zool 2010; 7:25. [PMID: 20831795 PMCID: PMC2945339 DOI: 10.1186/1742-9994-7-25] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2010] [Accepted: 09/10/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Several lineages within the Crustacea conquered land independently during evolution, thereby requiring physiological adaptations for a semi-terrestrial or even a fully terrestrial lifestyle. Birgus latro Linnaeus, 1767, the giant robber crab or coconut crab (Anomura, Coenobitidae), is the largest land-living arthropod and inhabits Indo-Pacific islands such as Christmas Island. B. latro has served as a model in numerous studies of physiological aspects related to the conquest of land by crustaceans. From an olfactory point of view, a transition from sea to land means that molecules need to be detected in gas phase instead of in water solution. Previous studies have provided physiological evidence that terrestrial hermit crabs (Coenobitidae) such as B. latro have a sensitive and well differentiated sense of smell. Here we analyze the brain, in particular the olfactory processing areas of B. latro, by morphological analysis followed by 3 D reconstruction and immunocytochemical studies of synaptic proteins and a neuropeptide. RESULTS The primary and secondary olfactory centers dominate the brain of B. latro and together account for ca. 40% of the neuropil volume in its brain. The paired olfactory neuropils are tripartite and composed of more than 1,000 columnar olfactory glomeruli, which are radially arranged around the periphery of the olfactory neuropils. The glomeruli are innervated ca. 90,000 local interneurons and ca. 160,000 projection neurons per side. The secondary olfactory centers, the paired hemiellipsoid neuropils, are targeted by the axons of these olfactory projection neurons. The projection neuron axonal branches make contact to ca. 250.000 interneurons (per side) associated with the hemiellipsoid neuropils. The hemiellipsoid body neuropil is organized into parallel neuropil lamellae, a design that is quite unusual for decapod crustaceans. The architecture of the optic neuropils and areas associated with antenna two suggest that B. latro has visual and mechanosensory skills that are comparable to those of marine Crustacea. CONCLUSIONS In parallel to previous behavioral findings that B. latro has aerial olfaction, our results indicate that their central olfactory pathway is indeed most prominent. Similar findings from the closely related terrestrial hermit crab Coenobita clypeatus suggest that in Coenobitidae, olfaction is a major sensory modality processed by the brain, and that for these animals, exploring the olfactory landscape is vital for survival in their terrestrial habitat. Future studies on terrestrial members of other crustacean taxa such as Isopoda, Amphipoda, Astacida, and Brachyura will shed light on how frequently the establishment of an aerial sense of olfaction evolved in Crustacea during the transition from sea to land. Amounting to ca. 1,000,000, the numbers of interneurons that analyse the olfactory input in B. latro brains surpasses that in other terrestrial arthropods, as e.g. the honeybee Apis mellifera or the moth Manduca sexta, by two orders of magnitude suggesting that B. latro in fact is a land-living arthropod that has devoted a substantial amount of nervous tissue to the sense of smell.
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Affiliation(s)
- Jakob Krieger
- Institute of Zoology, Department of Cytology and Evolution, University of Greifswald, Johann-Sebastian-Bach-Straße 11/12, D-17487 Greifswald, Germany
| | - Renate E Sandeman
- Justus-Liebig-Universität Gießen, Fachbereich 06 Psychologie und Sportwissenschaft, Abteilung für Entwicklungspsychologie, Otto-Behaghel-Strasse 10F, D-35394 Giessen, Germany
| | - David C Sandeman
- Wellesley College, 106 Central Street, Wellesley College, Department of Biological Sciences, Wellesley, MA 02481-8203, USA
| | - Bill S Hansson
- Max Planck Institute for Chemical Ecology, Department of Evolutionary Neuroethology, Beutenberg Campus, Hans-Knöll-Str. 8, D-07745 Jena, Germany
| | - Steffen Harzsch
- Institute of Zoology, Department of Cytology and Evolution, University of Greifswald, Johann-Sebastian-Bach-Straße 11/12, D-17487 Greifswald, Germany.,Max Planck Institute for Chemical Ecology, Department of Evolutionary Neuroethology, Beutenberg Campus, Hans-Knöll-Str. 8, D-07745 Jena, Germany
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Kreissl S, Strasser C, Galizia CG. Allatostatin immunoreactivity in the honeybee brain. J Comp Neurol 2010; 518:1391-417. [PMID: 20187126 DOI: 10.1002/cne.22343] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Information transmission and processing in the brain is achieved through a small family of chemical neurotransmitters and neuromodulators and a very large family of neuropeptides. In order to understand neural networks in the brain it will be necessary, therefore, to understand the connectivity, morphology, and distribution of peptidergic neurons, and to elucidate their function in the brain. In this study we characterize the distribution of substances related to Dip-allatostatin I in the honeybee brain, which belongs to the allatostatin-A (AST) peptide family sharing the conserved c-terminal sequence -YXFGL-NH(2). We found about 500 AST-immunoreactive (ASTir) neurons in the brain, scattered in 18 groups that varied in their precise location across individuals. Almost all areas of the brain were innervated by ASTir fibers. Most ASTir neurites formed networks within functionally distinct areas, e.g., the antennal lobes, the mushroom bodies, or the optic lobes, indicating local functions of the peptide. A small number of very large neurons had widespread arborizations and neurites were found in the corpora cardiaca and in the cervical connectives, suggesting that AST also has global functions. We double-stained AST and GABA and found that a subset of ASTir neurons were GABA-immunoreactive (GABAir). Double staining AST with backfills of olfactory receptor neurons or mass fills of neurons in the antennal lobes and in the mushroom bodies allowed a more fine-grained description of ASTir networks. Together, this first comprehensive description of AST in the bee brain suggests a diverse functional role of AST, including local and global computational tasks.
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Affiliation(s)
- Sabine Kreissl
- Department of Biology, University of Konstanz, D-78457 Konstanz, Germany
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