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Qi C, Qian C, Steijvers E, Colvin RA, Lee D. Single dopaminergic neuron DAN-c1 in Drosophila larval brain mediates aversive olfactory learning through D2-like receptors. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.15.575767. [PMID: 38293177 PMCID: PMC10827047 DOI: 10.1101/2024.01.15.575767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
The intricate relationship between the dopaminergic system and olfactory associative learning in Drosophila has been an intense scientific inquiry. Leveraging the formidable genetic tools, we conducted a screening of 57 dopaminergic drivers, leading to the discovery of DAN-c1 driver, uniquely targeting the single dopaminergic neuron (DAN) in each brain hemisphere. While the involvement of excitatory D1-like receptors is well-established, the role of D2-like receptors (D2Rs) remains underexplored. Our investigation reveals the expression of D2Rs in both DANs and the mushroom body (MB) of third instar larval brains. Silencing D2Rs in DAN-c1 via microRNA disrupts aversive learning, further supported by optogenetic activation of DAN-c1 during training, affirming the inhibitory role of D2R autoreceptor. Intriguingly, D2R knockdown in the MB impairs both appetitive and aversive learning. These findings elucidate the distinct contributions of D2Rs in diverse brain structures, providing novel insights into the molecular mechanisms governing associative learning in Drosophila larvae.
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Affiliation(s)
- Cheng Qi
- Department of Biological Sciences, Ohio University, Athens, OH 45701, USA
| | | | | | - Robert A. Colvin
- Department of Biological Sciences, Ohio University, Athens, OH 45701, USA
| | - Daewoo Lee
- Department of Biological Sciences, Ohio University, Athens, OH 45701, USA
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2
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Jiang X, Dimitriou E, Grabe V, Sun R, Chang H, Zhang Y, Gershenzon J, Rybak J, Hansson BS, Sachse S. Ring-shaped odor coding in the antennal lobe of migratory locusts. Cell 2024:S0092-8674(24)00580-4. [PMID: 38897195 DOI: 10.1016/j.cell.2024.05.036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 04/05/2024] [Accepted: 05/20/2024] [Indexed: 06/21/2024]
Abstract
The representation of odors in the locust antennal lobe with its >2,000 glomeruli has long remained a perplexing puzzle. We employed the CRISPR-Cas9 system to generate transgenic locusts expressing the genetically encoded calcium indicator GCaMP in olfactory sensory neurons. Using two-photon functional imaging, we mapped the spatial activation patterns representing a wide range of ecologically relevant odors across all six developmental stages. Our findings reveal a functionally ring-shaped organization of the antennal lobe composed of specific glomerular clusters. This configuration establishes an odor-specific chemotopic representation by encoding different chemical classes and ecologically distinct odors in the form of glomerular rings. The ring-shaped glomerular arrangement, which we confirm by selective targeting of OR70a-expressing sensory neurons, occurs throughout development, and the odor-coding pattern within the glomerular population is consistent across developmental stages. Mechanistically, this unconventional spatial olfactory code reflects the locust-specific and multiplexed glomerular innervation pattern of the antennal lobe.
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Affiliation(s)
- Xingcong Jiang
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, 07745 Jena, Germany; Research Group Olfactory Coding, Max Planck Institute for Chemical Ecology, 07745 Jena, Germany
| | - Eleftherios Dimitriou
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, 07745 Jena, Germany
| | - Veit Grabe
- Microscopic Service Group, Max Planck Institute for Chemical Ecology, 07745 Jena, Germany
| | - Ruo Sun
- Department of Biochemistry, Max Planck Institute for Chemical Ecology, 07745 Jena, Germany
| | - Hetan Chang
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, 07745 Jena, Germany
| | - Yifu Zhang
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, 07745 Jena, Germany
| | - Jonathan Gershenzon
- Department of Biochemistry, Max Planck Institute for Chemical Ecology, 07745 Jena, Germany
| | - Jürgen Rybak
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, 07745 Jena, Germany
| | - Bill S Hansson
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, 07745 Jena, Germany.
| | - Silke Sachse
- Research Group Olfactory Coding, Max Planck Institute for Chemical Ecology, 07745 Jena, Germany.
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3
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Wang Q, Smid HM, Dicke M, Haverkamp A. The olfactory system of Pieris brassicae caterpillars: from receptors to glomeruli. INSECT SCIENCE 2024; 31:469-488. [PMID: 38105530 DOI: 10.1111/1744-7917.13304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 10/17/2023] [Accepted: 10/30/2023] [Indexed: 12/19/2023]
Abstract
The olfactory system of adult lepidopterans is among the best described neuronal circuits. However, comparatively little is known about the organization of the olfactory system in the larval stage of these insects. Here, we explore the expression of olfactory receptors and the organization of olfactory sensory neurons in caterpillars of Pieris brassicae, a significant pest species in Europe and a well-studied species for its chemical ecology. To describe the larval olfactory system in this species, we first analyzed the head transcriptome of third-instar larvae (L3) and identified 16 odorant receptors (ORs) including the OR coreceptor (Orco), 13 ionotropic receptors (IRs), and 8 gustatory receptors (GRs). We then quantified the expression of these 16 ORs in different life stages, using qPCR, and found that the majority of ORs had significantly higher expression in the L4 stage than in the L3 and L5 stages, indicating that the larval olfactory system is not static throughout caterpillar development. Using an Orco-specific antibody, we identified all olfactory receptor neurons (ORNs) expressing the Orco protein in L3, L4, and L5 caterpillars and found a total of 34 Orco-positive ORNs, distributed among three sensilla on the antenna. The number of Orco-positive ORNs did not differ among the three larval instars. Finally, we used retrograde axon tracing of the antennal nerve and identified a mean of 15 glomeruli in the larval antennal center (LAC), suggesting that the caterpillar olfactory system follows a similar design as the adult olfactory system, although with a lower numerical redundancy. Taken together, our results provide a detailed analysis of the larval olfactory neurons in P. brassicae, highlighting both the differences as well as the commonalities with the adult olfactory system. These findings contribute to a better understanding of the development of the olfactory system in insects and its life-stage-specific adaptations.
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Affiliation(s)
- Qi Wang
- Laboratory of Entomology, Wageningen University and Research, Wageningen, the Netherlands
| | - Hans M Smid
- Laboratory of Entomology, Wageningen University and Research, Wageningen, the Netherlands
| | - Marcel Dicke
- Laboratory of Entomology, Wageningen University and Research, Wageningen, the Netherlands
| | - Alexander Haverkamp
- Laboratory of Entomology, Wageningen University and Research, Wageningen, the Netherlands
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4
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Yoon S, Shin M, Shim J. Inter-organ regulation by the brain in Drosophila development and physiology. J Neurogenet 2022:1-13. [DOI: 10.1080/01677063.2022.2137162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Sunggyu Yoon
- Department of Life Sciences, College of Natural Science, Hanyang University, Seoul, Republic of Korea
| | - Mingyu Shin
- Department of Life Sciences, College of Natural Science, Hanyang University, Seoul, Republic of Korea
| | - Jiwon Shim
- Department of Life Sciences, College of Natural Science, Hanyang University, Seoul, Republic of Korea
- Research Institute for Natural Science, Hanyang University, Seoul, Republic of Korea
- Hanyang Institute of Bioscience and Biotechnology, Hanyang University, Seoul, Republic of Korea
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Circuit analysis reveals a neural pathway for light avoidance in Drosophila larvae. Nat Commun 2022; 13:5274. [PMID: 36071059 PMCID: PMC9452580 DOI: 10.1038/s41467-022-33059-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 08/31/2022] [Indexed: 11/30/2022] Open
Abstract
Understanding how neural circuits underlie behaviour is challenging even in the connectome era because it requires a combination of anatomical and functional analyses. This is exemplified in the circuit underlying the light avoidance behaviour displayed by Drosophila melanogaster larvae. While this behaviour is robust and the nervous system relatively simple, the circuit is only partially delineated with some contradictions among studies. Here, we devise trans-Tango MkII, an offshoot of the transsynaptic circuit tracing tool trans-Tango, and implement it in anatomical tracing together with functional analysis. We use neuronal inhibition to test necessity of particular neuronal types in light avoidance and selective neuronal activation to examine sufficiency in rescuing light avoidance deficiencies exhibited by photoreceptor mutants. Our studies reveal a four-order circuit for light avoidance connecting the light-detecting photoreceptors with a pair of neuroendocrine cells via two types of clock neurons. This approach can be readily expanded to studying other circuits. Studying neural circuits requires a multipronged approach. Here, the authors present a transsynaptic tracing tool in fruit fly larvae and combine it with neuronal inhibition and activation to study the circuit underlying light avoidance behaviour.
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Duhart JC, Mosca TJ. Genetic regulation of central synapse formation and organization in Drosophila melanogaster. Genetics 2022; 221:6597078. [PMID: 35652253 DOI: 10.1093/genetics/iyac078] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 04/29/2022] [Indexed: 01/04/2023] Open
Abstract
A goal of modern neuroscience involves understanding how connections in the brain form and function. Such a knowledge is essential to inform how defects in the exquisite complexity of nervous system growth influence neurological disease. Studies of the nervous system in the fruit fly Drosophila melanogaster enabled the discovery of a wealth of molecular and genetic mechanisms underlying development of synapses-the specialized cell-to-cell connections that comprise the essential substrate for information flow and processing in the nervous system. For years, the major driver of knowledge was the neuromuscular junction due to its ease of examination. Analogous studies in the central nervous system lagged due to a lack of genetic accessibility of specific neuron classes, synaptic labels compatible with cell-type-specific access, and high resolution, quantitative imaging strategies. However, understanding how central synapses form remains a prerequisite to understanding brain development. In the last decade, a host of new tools and techniques extended genetic studies of synapse organization into central circuits to enhance our understanding of synapse formation, organization, and maturation. In this review, we consider the current state-of-the-field. We first discuss the tools, technologies, and strategies developed to visualize and quantify synapses in vivo in genetically identifiable neurons of the Drosophila central nervous system. Second, we explore how these tools enabled a clearer understanding of synaptic development and organization in the fly brain and the underlying molecular mechanisms of synapse formation. These studies establish the fly as a powerful in vivo genetic model that offers novel insights into neural development.
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Affiliation(s)
- Juan Carlos Duhart
- Department of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Timothy J Mosca
- Department of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107, USA
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Hiratani N, Latham PE. Developmental and evolutionary constraints on olfactory circuit selection. Proc Natl Acad Sci U S A 2022; 119:e2100600119. [PMID: 35263217 PMCID: PMC8931209 DOI: 10.1073/pnas.2100600119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 01/14/2022] [Indexed: 11/18/2022] Open
Abstract
SignificanceIn this work, we explore the hypothesis that biological neural networks optimize their architecture, through evolution, for learning. We study early olfactory circuits of mammals and insects, which have relatively similar structure but a huge diversity in size. We approximate these circuits as three-layer networks and estimate, analytically, the scaling of the optimal hidden-layer size with input-layer size. We find that both longevity and information in the genome constrain the hidden-layer size, so a range of allometric scalings is possible. However, the experimentally observed allometric scalings in mammals and insects are consistent with biologically plausible values. This analysis should pave the way for a deeper understanding of both biological and artificial networks.
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Affiliation(s)
- Naoki Hiratani
- Gatsby Computational Neuroscience Unit, University College London, London W1T 4JG, United Kingdom
| | - Peter E. Latham
- Gatsby Computational Neuroscience Unit, University College London, London W1T 4JG, United Kingdom
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Drosophila melanogaster Chemosensory Pathways as Potential Targets to Curb the Insect Menace. INSECTS 2022; 13:insects13020142. [PMID: 35206716 PMCID: PMC8874460 DOI: 10.3390/insects13020142] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 01/19/2022] [Accepted: 01/25/2022] [Indexed: 11/17/2022]
Abstract
Simple Summary The perception and processing of chemosensory stimuli are indispensable to the survival of living organisms. In insects, olfaction and gustation play a critical role in seeking food, finding mates and avoiding signs of danger. This review aims to present updated information about olfactory and gustatory signaling in the fruit fly Drosophila melanogaster. We have described the mechanisms involved in olfactory and gustatory perceptions at the molecular level, the receptors along with the allied molecules involved, and their signaling pathways in the fruit fly. Due to the magnifying problems of disease-causing insect vectors and crop pests, the applications of chemosensory signaling in controlling pests and insect vectors are also discussed. Abstract From a unicellular bacterium to a more complex human, smell and taste form an integral part of the basic sensory system. In fruit flies Drosophila melanogaster, the behavioral responses to odorants and tastants are simple, though quite sensitive, and robust. They explain the organization and elementary functioning of the chemosensory system. Molecular and functional analyses of the receptors and other critical molecules involved in olfaction and gustation are not yet completely understood. Hence, a better understanding of chemosensory cue-dependent fruit flies, playing a major role in deciphering the host-seeking behavior of pathogen transmitting insect vectors (mosquitoes, sandflies, ticks) and crop pests (Drosophila suzukii, Queensland fruit fly), is needed. Using D. melanogaster as a model organism, the knowledge gained may be implemented to design new means of controlling insects as well as in analyzing current batches of insect and pest repellents. In this review, the complete mechanisms of olfactory and gustatory perception, along with their implementation in controlling the global threat of disease-transmitting insect vectors and crop-damaging pests, are explained in fruit flies.
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Komarov N, Sprecher SG. The chemosensory system of the Drosophila larva: an overview of current understanding. Fly (Austin) 2021; 16:1-12. [PMID: 34612150 PMCID: PMC8496535 DOI: 10.1080/19336934.2021.1953364] [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] [Indexed: 12/27/2022] Open
Abstract
Animals must sense their surroundings and be able to distinguish between relevant and irrelevant cues. An enticing area of research aims to uncover the mechanisms by which animals respond to chemical signals that constitute critical sensory input. In this review, we describe the principles of a model chemosensory system: the Drosophila larva. While distinct in many ways, larval behaviour is reminiscent of the dogmatic goals of life: to reach a stage of reproductive potential. It takes into account a number of distinct and identifiable parameters to ultimately provoke or modulate appropriate behavioural output. In this light, we describe current knowledge of chemosensory anatomy, genetic components, and the processing logic of chemical cues. We outline recent advancements and summarize the hypothesized neural circuits of sensory systems. Furthermore, we note yet-unanswered questions to create a basis for further investigation of molecular and systemic mechanisms of chemosensation in Drosophila and beyond.
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Affiliation(s)
- Nikita Komarov
- Institute of Cell and Developmental Biology, Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Simon G Sprecher
- Institute of Cell and Developmental Biology, Department of Biology, University of Fribourg, Fribourg, Switzerland
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10
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Trebels B, Dippel S, Goetz B, Graebner M, Hofmann C, Hofmann F, Schmid FR, Uhl M, Vuong MP, Weber V, Schachtner J. Metamorphic development of the olfactory system in the red flour beetle (Tribolium castaneum, HERBST). BMC Biol 2021; 19:155. [PMID: 34330268 PMCID: PMC8323255 DOI: 10.1186/s12915-021-01055-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 05/25/2021] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Insects depend on their olfactory sense as a vital system. Olfactory cues are processed by a rather complex system and translated into various types of behavior. In holometabolous insects like the red flour beetle Tribolium castaneum, the nervous system typically undergoes considerable remodeling during metamorphosis. This process includes the integration of new neurons, as well as remodeling and elimination of larval neurons. RESULTS We find that the sensory neurons of the larval antennae are reused in the adult antennae. Further, the larval antennal lobe gets transformed into its adult version. The beetle's larval antennal lobe is already glomerularly structured, but its glomeruli dissolve in the last larval stage. However, the axons of the olfactory sensory neurons remain within the antennal lobe volume. The glomeruli of the adult antennal lobe then form from mid-metamorphosis independently of the presence of a functional OR/Orco complex but mature dependent on the latter during a postmetamorphic phase. CONCLUSIONS We provide insights into the metamorphic development of the red flour beetle's olfactory system and compared it to data on Drosophila melanogaster, Manduca sexta, and Apis mellifera. The comparison revealed that some aspects, such as the formation of the antennal lobe's adult glomeruli at mid-metamorphosis, are common, while others like the development of sensory appendages or the role of Orco seemingly differ.
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Affiliation(s)
- Björn Trebels
- Department of Biology, Animal Physiology, Philipps-University Marburg, Karl-von-Frisch-Str. 8, 35032 Marburg, Germany
| | - Stefan Dippel
- Department of Biology, Animal Physiology, Philipps-University Marburg, Karl-von-Frisch-Str. 8, 35032 Marburg, Germany
| | - Brigitte Goetz
- Department of Biology, Animal Physiology, Philipps-University Marburg, Karl-von-Frisch-Str. 8, 35032 Marburg, Germany
| | - Maria Graebner
- Department of Biology, Animal Physiology, Philipps-University Marburg, Karl-von-Frisch-Str. 8, 35032 Marburg, Germany
| | - Carolin Hofmann
- Department of Biology, Animal Physiology, Philipps-University Marburg, Karl-von-Frisch-Str. 8, 35032 Marburg, Germany
| | - Florian Hofmann
- Department of Biology, Animal Physiology, Philipps-University Marburg, Karl-von-Frisch-Str. 8, 35032 Marburg, Germany
| | - Freya-Rebecca Schmid
- Department of Biology, Animal Physiology, Philipps-University Marburg, Karl-von-Frisch-Str. 8, 35032 Marburg, Germany
| | - Mara Uhl
- Department of Biology, Animal Physiology, Philipps-University Marburg, Karl-von-Frisch-Str. 8, 35032 Marburg, Germany
| | - Minh-Phung Vuong
- Department of Biology, Animal Physiology, Philipps-University Marburg, Karl-von-Frisch-Str. 8, 35032 Marburg, Germany
| | - Vanessa Weber
- Department of Biology, Animal Physiology, Philipps-University Marburg, Karl-von-Frisch-Str. 8, 35032 Marburg, Germany
| | - Joachim Schachtner
- Department of Biology, Animal Physiology, Philipps-University Marburg, Karl-von-Frisch-Str. 8, 35032 Marburg, Germany
- Clausthal University of Technology, Adolph-Roemer-Str. 2a, 38678 Clausthal-Zellerfeld, Germany
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11
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Coll-Tané M, Gong NN, Belfer SJ, van Renssen LV, Kurtz-Nelson EC, Szuperak M, Eidhof I, van Reijmersdal B, Terwindt I, Durkin J, Verheij MMM, Kim CN, Hudac CM, Nowakowski TJ, Bernier RA, Pillen S, Earl RK, Eichler EE, Kleefstra T, Kayser MS, Schenck A. The CHD8/CHD7/Kismet family links blood-brain barrier glia and serotonin to ASD-associated sleep defects. SCIENCE ADVANCES 2021; 7:7/23/eabe2626. [PMID: 34088660 PMCID: PMC8177706 DOI: 10.1126/sciadv.abe2626] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 04/19/2021] [Indexed: 05/11/2023]
Abstract
Sleep disturbances in autism and neurodevelopmental disorders are common and adversely affect patient's quality of life, yet the underlying mechanisms are understudied. We found that individuals with mutations in CHD8, among the highest-confidence autism risk genes, or CHD7 suffer from disturbed sleep maintenance. These defects are recapitulated in Drosophila mutants affecting kismet, the sole CHD8/CHD7 ortholog. We show that Kismet is required in glia for early developmental and adult sleep architecture. This role localizes to subperineurial glia constituting the blood-brain barrier. We demonstrate that Kismet-related sleep disturbances are caused by high serotonin during development, paralleling a well-established but genetically unsolved autism endophenotype. Despite their developmental origin, Kismet's sleep architecture defects can be reversed in adulthood by a behavioral regime resembling human sleep restriction therapy. Our findings provide fundamental insights into glial regulation of sleep and propose a causal mechanistic link between the CHD8/CHD7/Kismet family, developmental hyperserotonemia, and autism-associated sleep disturbances.
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Affiliation(s)
- Mireia Coll-Tané
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud university medical center, 6525 GA, Nijmegen, Netherlands.
| | - Naihua N Gong
- Departments of Psychiatry and Neuroscience, Chronobiology and Sleep Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Samuel J Belfer
- Departments of Psychiatry and Neuroscience, Chronobiology and Sleep Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Lara V van Renssen
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud university medical center, 6525 GA, Nijmegen, Netherlands
| | | | - Milan Szuperak
- Departments of Psychiatry and Neuroscience, Chronobiology and Sleep Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ilse Eidhof
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud university medical center, 6525 GA, Nijmegen, Netherlands
| | - Boyd van Reijmersdal
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud university medical center, 6525 GA, Nijmegen, Netherlands
| | - Isabel Terwindt
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud university medical center, 6525 GA, Nijmegen, Netherlands
| | - Jaclyn Durkin
- Departments of Psychiatry and Neuroscience, Chronobiology and Sleep Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Michel M M Verheij
- Department of Cognitive Neuroscience, Centre for Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboud university medical center, Nijmegen, Netherlands
| | - Chang N Kim
- Departments of Anatomy and Psychiatry, University of California, San Francisco, CA 94143 USA
| | - Caitlin M Hudac
- Center for Youth Development and Intervention and Department of Psychology, University of Alabama, Tuscaloosa, AL 35487, USA
| | - Tomasz J Nowakowski
- Departments of Anatomy and Psychiatry, University of California, San Francisco, CA 94143 USA
| | - Raphael A Bernier
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA 98185, USA
| | - Sigrid Pillen
- Center for Sleep Medicine, Kempenhaeghe, Heeze, Netherlands
| | - Rachel K Earl
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA 98185, USA
| | - Evan E Eichler
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, WA 98195, USA
- Howard Hughes Medical Institute, University of Washington, Seattle, WA, USA
| | - Tjitske Kleefstra
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud university medical center, 6525 GA, Nijmegen, Netherlands
| | - Matthew S Kayser
- Departments of Psychiatry and Neuroscience, Chronobiology and Sleep Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Annette Schenck
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud university medical center, 6525 GA, Nijmegen, Netherlands.
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12
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Puñal VM, Ahmed M, Thornton-Kolbe EM, Clowney EJ. Untangling the wires: development of sparse, distributed connectivity in the mushroom body calyx. Cell Tissue Res 2021; 383:91-112. [PMID: 33404837 PMCID: PMC9835099 DOI: 10.1007/s00441-020-03386-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 12/07/2020] [Indexed: 01/16/2023]
Abstract
Appropriate perception and representation of sensory stimuli pose an everyday challenge to the brain. In order to represent the wide and unpredictable array of environmental stimuli, principle neurons of associative learning regions receive sparse, combinatorial sensory inputs. Despite the broad role of such networks in sensory neural circuits, the developmental mechanisms underlying their emergence are not well understood. As mammalian sensory coding regions are numerically complex and lack the accessibility of simpler invertebrate systems, we chose to focus this review on the numerically simpler, yet functionally similar, Drosophila mushroom body calyx. We bring together current knowledge about the cellular and molecular mechanisms orchestrating calyx development, in addition to drawing insights from literature regarding construction of sparse wiring in the mammalian cerebellum. From this, we formulate hypotheses to guide our future understanding of the development of this critical perceptual center.
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Affiliation(s)
- Vanessa M. Puñal
- Department of Molecular, Cellular & Developmental Biology, The University of Michigan, Ann Arbor, MI 48109, USA,Department of Molecular & Integrative Physiology, The University of Michigan, Ann Arbor, MI 48109, USA
| | - Maria Ahmed
- Department of Molecular, Cellular & Developmental Biology, The University of Michigan, Ann Arbor, MI 48109, USA
| | - Emma M. Thornton-Kolbe
- Department of Molecular, Cellular & Developmental Biology, The University of Michigan, Ann Arbor, MI 48109, USA,Neuroscience Graduate Program, The University of Michigan, Ann Arbor, MI 48109, USA
| | - E. Josephine Clowney
- Department of Molecular, Cellular & Developmental Biology, The University of Michigan, Ann Arbor, MI 48109, USA
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Hartenstein V, Omoto JJ, Lovick JK. The role of cell lineage in the development of neuronal circuitry and function. Dev Biol 2020; 475:165-180. [PMID: 32017903 DOI: 10.1016/j.ydbio.2020.01.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 01/23/2020] [Accepted: 01/23/2020] [Indexed: 12/13/2022]
Abstract
Complex nervous systems have a modular architecture, whereby reiterative groups of neurons ("modules") that share certain structural and functional properties are integrated into large neural circuits. Neurons develop from proliferating progenitor cells that, based on their location and time of appearance, are defined by certain genetic programs. Given that genes expressed by a given progenitor play a fundamental role in determining the properties of its lineage (i.e., the neurons descended from that progenitor), one efficient developmental strategy would be to have lineages give rise to the structural modules of the mature nervous system. It is clear that this strategy plays an important role in neural development of many invertebrate animals, notably insects, where the availability of genetic techniques has made it possible to analyze the precise relationship between neuronal origin and differentiation since several decades. Similar techniques, developed more recently in the vertebrate field, reveal that functional modules of the mammalian cerebral cortex are also likely products of developmentally defined lineages. We will review studies that relate cell lineage to circuitry and function from a comparative developmental perspective, aiming at enhancing our understanding of neural progenitors and their lineages, and translating findings acquired in different model systems into a common conceptual framework.
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Affiliation(s)
- Volker Hartenstein
- Department of Molecular Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA, 90095, USA.
| | - Jaison J Omoto
- Department of Molecular Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Jennifer K Lovick
- Department of Molecular Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA, 90095, USA
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14
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Elkahlah NA, Rogow JA, Ahmed M, Clowney EJ. Presynaptic developmental plasticity allows robust sparse wiring of the Drosophila mushroom body. eLife 2020; 9:e52278. [PMID: 31913123 PMCID: PMC7028369 DOI: 10.7554/elife.52278] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2019] [Accepted: 01/07/2020] [Indexed: 01/29/2023] Open
Abstract
In order to represent complex stimuli, principle neurons of associative learning regions receive combinatorial sensory inputs. Density of combinatorial innervation is theorized to determine the number of distinct stimuli that can be represented and distinguished from one another, with sparse innervation thought to optimize the complexity of representations in networks of limited size. How the convergence of combinatorial inputs to principle neurons of associative brain regions is established during development is unknown. Here, we explore the developmental patterning of sparse olfactory inputs to Kenyon cells of the Drosophila melanogaster mushroom body. By manipulating the ratio between pre- and post-synaptic cells, we find that postsynaptic Kenyon cells set convergence ratio: Kenyon cells produce fixed distributions of dendritic claws while presynaptic processes are plastic. Moreover, we show that sparse odor responses are preserved in mushroom bodies with reduced cellular repertoires, suggesting that developmental specification of convergence ratio allows functional robustness.
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Affiliation(s)
- Najia A Elkahlah
- Department of Molecular, Cellular and Developmental BiologyThe University of MichiganAnn ArborUnited States
| | - Jackson A Rogow
- Laboratory of Neurophysiology and BehaviorThe Rockefeller UniversityNew YorkUnited States
| | - Maria Ahmed
- Department of Molecular, Cellular and Developmental BiologyThe University of MichiganAnn ArborUnited States
| | - E Josephine Clowney
- Department of Molecular, Cellular and Developmental BiologyThe University of MichiganAnn ArborUnited States
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15
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Affiliation(s)
- Nadine Ehmann
- Department of Animal Physiology, Institute of Biology, Leipzig University, Leipzig, Germany
| | - Dennis Pauls
- Department of Animal Physiology, Institute of Biology, Leipzig University, Leipzig, Germany
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16
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Si G, Kanwal JK, Hu Y, Tabone CJ, Baron J, Berck M, Vignoud G, Samuel ADT. Structured Odorant Response Patterns across a Complete Olfactory Receptor Neuron Population. Neuron 2019; 101:950-962.e7. [PMID: 30683545 DOI: 10.1016/j.neuron.2018.12.030] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 10/29/2018] [Accepted: 12/20/2018] [Indexed: 11/15/2022]
Abstract
Odor perception allows animals to distinguish odors, recognize the same odor across concentrations, and determine concentration changes. How the activity patterns of primary olfactory receptor neurons (ORNs), at the individual and population levels, facilitate distinguishing these functions remains poorly understood. Here, we interrogate the complete ORN population of the Drosophila larva across a broadly sampled panel of odorants at varying concentrations. We find that the activity of each ORN scales with the concentration of any odorant via a fixed dose-response function with a variable sensitivity. Sensitivities across odorants and ORNs follow a power-law distribution. Much of receptor sensitivity to odorants is accounted for by a single geometrical property of molecular structure. Similarity in the shape of temporal response filters across odorants and ORNs extend these relationships to fluctuating environments. These results uncover shared individual- and population-level patterns that together lend structure to support odor perceptions.
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Affiliation(s)
- Guangwei Si
- Department of Physics, Harvard University, Cambridge, MA 02138, USA; Center for Brain Science, Harvard University, Cambridge, MA 02138, USA
| | - Jessleen K Kanwal
- Center for Brain Science, Harvard University, Cambridge, MA 02138, USA; Program in Neuroscience, Harvard University, Cambridge, MA 02138, USA
| | - Yu Hu
- Center for Brain Science, Harvard University, Cambridge, MA 02138, USA
| | - Christopher J Tabone
- Department of Physics, Harvard University, Cambridge, MA 02138, USA; Center for Brain Science, Harvard University, Cambridge, MA 02138, USA
| | - Jacob Baron
- Department of Physics, Harvard University, Cambridge, MA 02138, USA; Center for Brain Science, Harvard University, Cambridge, MA 02138, USA
| | - Matthew Berck
- Department of Physics, Harvard University, Cambridge, MA 02138, USA; Center for Brain Science, Harvard University, Cambridge, MA 02138, USA
| | - Gaetan Vignoud
- Department of Physics, Harvard University, Cambridge, MA 02138, USA; Center for Brain Science, Harvard University, Cambridge, MA 02138, USA
| | - Aravinthan D T Samuel
- Department of Physics, Harvard University, Cambridge, MA 02138, USA; Center for Brain Science, Harvard University, Cambridge, MA 02138, USA.
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17
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Clark DA, Odell SR, Armstrong JM, Turcotte M, Kohler D, Mathis A, Schmidt DR, Mathew D. Behavior Responses to Chemical and Optogenetic Stimuli in Drosophila Larvae. Front Behav Neurosci 2018; 12:324. [PMID: 30622461 PMCID: PMC6308144 DOI: 10.3389/fnbeh.2018.00324] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 12/10/2018] [Indexed: 11/13/2022] Open
Abstract
An animal’s ability to navigate an olfactory environment is critically dependent on the activities of its first-order olfactory receptor neurons (ORNs). While considerable research has focused on ORN responses to odorants, the mechanisms by which olfactory information is encoded in the activities of ORNs and translated into navigational behavior remain poorly understood. We sought to determine the contributions of most Drosophila melanogaster larval ORNs to navigational behavior. Using odorants to activate ORNs and a larval tracking assay to measure the corresponding behavioral response, we observed that larval ORN activators cluster into four groups based on the behavior responses elicited from larvae. This is significant because it provides new insights into the functional relationship between ORN activity and behavioral response. Subsequent optogenetic analyses of a subset of ORNs revealed previously undescribed properties of larval ORNs. Furthermore, our results indicated that different temporal patterns of ORN activation elicit different behavioral outputs: some ORNs respond to stimulus increments while others respond to stimulus decrements. These results suggest that the ability of ORNs to encode temporal patterns of stimulation increases the coding capacity of the olfactory circuit. Moreover, the ability of ORNs to sense stimulus increments and decrements facilitates instantaneous evaluations of concentration changes in the environment. Together, these ORN properties enable larvae to efficiently navigate a complex olfactory environment. Ultimately, knowledge of how ORN activity patterns and their weighted contributions influence odor coding may eventually reveal how peripheral information is organized and transmitted to subsequent layers of a neural circuit.
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Affiliation(s)
- David A Clark
- Department of Biology, University of Nevada, Reno, NV, United States.,Integrated Neuroscience Graduate Program, University of Nevada, Reno, NV, United States
| | - Seth R Odell
- Department of Biology, University of Nevada, Reno, NV, United States.,Integrated Neuroscience Graduate Program, University of Nevada, Reno, NV, United States
| | - Joanna M Armstrong
- Department of Mathematics & Statistics, University of Nevada, Reno, NV, United States
| | - Mariah Turcotte
- Department of Biology, University of Nevada, Reno, NV, United States
| | - Donovan Kohler
- Department of Biology, University of Nevada, Reno, NV, United States
| | - America Mathis
- Department of Biology, University of Nevada, Reno, NV, United States
| | - Deena R Schmidt
- Integrated Neuroscience Graduate Program, University of Nevada, Reno, NV, United States.,Department of Mathematics & Statistics, University of Nevada, Reno, NV, United States
| | - Dennis Mathew
- Department of Biology, University of Nevada, Reno, NV, United States.,Integrated Neuroscience Graduate Program, University of Nevada, Reno, NV, United States
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18
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Ramon-Cañellas P, Peterson HP, Morante J. From Early to Late Neurogenesis: Neural Progenitors and the Glial Niche from a Fly's Point of View. Neuroscience 2018; 399:39-52. [PMID: 30578972 DOI: 10.1016/j.neuroscience.2018.12.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2018] [Revised: 12/06/2018] [Accepted: 12/12/2018] [Indexed: 12/15/2022]
Abstract
Drosophila melanogaster is an important model organism used to study the brain development of organisms ranging from insects to mammals. The central nervous system in fruit flies is formed primarily in two waves of neurogenesis, one of which occurs in the embryo and one of which occurs during larval stages. In order to understand neurogenesis, it is important to research the behavior of progenitor cells that give rise to the neural networks which make up the adult nervous system. This behavior has been shown to be influenced by different factors including interactions with other cells within the progenitor niche, or local tissue microenvironment. Glial cells form a crucial part of this niche and play an active role in the development of the brain. Although in the early years of neuroscience it was believed that glia were simply scaffolding for neurons and passive components of the nervous system, their importance is nowadays recognized. Recent discoveries in progenitors and niche cells have led to new understandings of how the developing brain shapes its diverse regions. In this review, we attempt to summarize the distinct neural progenitors and glia in the Drosophila melanogaster central nervous system, from embryo to late larval stages, and make note of homologous features in mammals. We also outline the recent advances in this field in order to define the impact that glial cells have on progenitor cell niches, and we finally emphasize the importance of communication between glia and progenitor cells for proper brain formation.
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Affiliation(s)
- Pol Ramon-Cañellas
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas (CSIC), and Universidad Miguel Hernández (UMH), Campus de Sant Joan, Apartado 18, 03550 Sant Joan, Alicante, Spain
| | - Hannah Payette Peterson
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas (CSIC), and Universidad Miguel Hernández (UMH), Campus de Sant Joan, Apartado 18, 03550 Sant Joan, Alicante, Spain
| | - Javier Morante
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas (CSIC), and Universidad Miguel Hernández (UMH), Campus de Sant Joan, Apartado 18, 03550 Sant Joan, Alicante, Spain.
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19
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Tastekin I, Khandelwal A, Tadres D, Fessner ND, Truman JW, Zlatic M, Cardona A, Louis M. Sensorimotor pathway controlling stopping behavior during chemotaxis in the Drosophila melanogaster larva. eLife 2018; 7:e38740. [PMID: 30465650 PMCID: PMC6264072 DOI: 10.7554/elife.38740] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 11/07/2018] [Indexed: 02/02/2023] Open
Abstract
Sensory navigation results from coordinated transitions between distinct behavioral programs. During chemotaxis in the Drosophila melanogaster larva, the detection of positive odor gradients extends runs while negative gradients promote stops and turns. This algorithm represents a foundation for the control of sensory navigation across phyla. In the present work, we identified an olfactory descending neuron, PDM-DN, which plays a pivotal role in the organization of stops and turns in response to the detection of graded changes in odor concentrations. Artificial activation of this descending neuron induces deterministic stops followed by the initiation of turning maneuvers through head casts. Using electron microscopy, we reconstructed the main pathway that connects the PDM-DN neuron to the peripheral olfactory system and to the pre-motor circuit responsible for the actuation of forward peristalsis. Our results set the stage for a detailed mechanistic analysis of the sensorimotor conversion of graded olfactory inputs into action selection to perform goal-oriented navigation.
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Affiliation(s)
- Ibrahim Tastekin
- EMBL-CRG Systems Biology Research UnitCentre for Genomic Regulation, The Barcelona Institute of Science and TechnologyBarcelonaSpain
- Universitat Pompeu FabraBarcelonaSpain
| | - Avinash Khandelwal
- EMBL-CRG Systems Biology Research UnitCentre for Genomic Regulation, The Barcelona Institute of Science and TechnologyBarcelonaSpain
- Janelia Research CampusHoward Hughes Medical InstituteAshburnUnited States
| | - David Tadres
- EMBL-CRG Systems Biology Research UnitCentre for Genomic Regulation, The Barcelona Institute of Science and TechnologyBarcelonaSpain
- Universitat Pompeu FabraBarcelonaSpain
- Institute of Molecular Life SciencesUniversity of ZurichZurichSwitzerland
- Department of Molecular, Cellular and Developmental Biology & Neuroscience Research InstituteUniversity of CaliforniaSanta BarbaraUnited States
| | - Nico D Fessner
- EMBL-CRG Systems Biology Research UnitCentre for Genomic Regulation, The Barcelona Institute of Science and TechnologyBarcelonaSpain
- Universitat Pompeu FabraBarcelonaSpain
| | - James W Truman
- Janelia Research CampusHoward Hughes Medical InstituteAshburnUnited States
| | - Marta Zlatic
- Janelia Research CampusHoward Hughes Medical InstituteAshburnUnited States
- Department of ZoologyUniversity of CambridgeCambridgeUnited Kingdom
| | - Albert Cardona
- Janelia Research CampusHoward Hughes Medical InstituteAshburnUnited States
- Department of Physiology, Development and NeuroscienceUniversity of CambridgeCambridgeUnited Kingdom
| | - Matthieu Louis
- EMBL-CRG Systems Biology Research UnitCentre for Genomic Regulation, The Barcelona Institute of Science and TechnologyBarcelonaSpain
- Universitat Pompeu FabraBarcelonaSpain
- Department of Molecular, Cellular and Developmental Biology & Neuroscience Research InstituteUniversity of CaliforniaSanta BarbaraUnited States
- Department of PhysicsUniversity of California Santa BarbaraCaliforniaUnited States
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20
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Connectomics and function of a memory network: the mushroom body of larval Drosophila. Curr Opin Neurobiol 2018; 54:146-154. [PMID: 30368037 DOI: 10.1016/j.conb.2018.10.007] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 10/04/2018] [Indexed: 11/20/2022]
Abstract
The Drosophila larva is a relatively simple, 10 000-neuron study case for learning and memory with enticing analytical power, combining genetic tractability, the availability of robust behavioral assays, the opportunity for single-cell transgenic manipulation, and an emerging synaptic connectome of its complete central nervous system. Indeed, although the insect mushroom body is a much-studied memory network, the connectome revealed that more than half of the classes of connection within the mushroom body had escaped attention. The connectome also revealed circuitry that integrates, both within and across brain hemispheres, higher-order sensory input, intersecting valence signals, and output neurons that instruct behavior. Further, it was found that activating individual dopaminergic mushroom body input neurons can have a rewarding or a punishing effect on olfactory stimuli associated with it, depending on the relative timing of this activation, and that larvae form molecularly dissociable short-term, long-term, and amnesia-resistant memories. Together, the larval mushroom body is a suitable study case to achieve a nuanced account of molecular function in a behaviorally meaningful memory network.
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21
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Two Drosophila Neuropeptide Y-like Neurons Define a Reward Module for Transforming Appetitive Odor Representations to Motivation. Sci Rep 2018; 8:11658. [PMID: 30076343 PMCID: PMC6076267 DOI: 10.1038/s41598-018-30113-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 07/24/2018] [Indexed: 01/15/2023] Open
Abstract
Neuropeptides, many of which are conserved among vertebrate and invertebrate animals, are implicated in the regulation of motivational states that selectively facilitate goal-directed behaviors. After a brief presentation of appetitive odors, Drosophila larvae display an impulsive-like feeding activity in readily accessible palatable food. This innate appetitive response may require coordinated signaling activities of dopamine (DA) and neuropeptide F (NPF; a fly homolog of neuropeptide Y). Here we provide anatomical and functional evidence, at single-cell resolution, that two NPF neurons define a reward module in the highest-order brain region for cognitive processing of food-related olfactory representations. First, laser lesioning of these NPF neurons abolished odor induction of appetitive arousal, while their genetic activation mimicked the behavioral effect of appetitive odors. Further, a circuit analysis shows that each of the two NPF neurons relays its signals to a subset of target neurons in the larval hindbrain-like region. Finally, the NPF neurons discriminatively responded to appetitive odor stimuli, and their odor responses were blocked by targeted lesioning of a pair of dopaminergic third-order olfactory neurons that appear to be presynaptic to the NPF neurons. Therefore, the two NPF neurons contribute to appetitive odor induction of impulsive-like feeding by selectively decoding DA-encoded ascending olfactory inputs and relaying NPF-encoded descending motivational outputs for behavioral execution.
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22
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Tomasiunaite U, Widmann A, Thum AS. Maggot Instructor: Semi-Automated Analysis of Learning and Memory in Drosophila Larvae. Front Psychol 2018; 9:1010. [PMID: 29973900 PMCID: PMC6019503 DOI: 10.3389/fpsyg.2018.01010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 05/31/2018] [Indexed: 11/21/2022] Open
Abstract
For several decades, Drosophila has been widely used as a suitable model organism to study the fundamental processes of associative olfactory learning and memory. More recently, this condition also became true for the Drosophila larva, which has become a focus for learning and memory studies based on a number of technical advances in the field of anatomical, molecular, and neuronal analyses. The ongoing efforts should be mentioned to reconstruct the complete connectome of the larval brain featuring a total of about 10,000 neurons and the development of neurogenic tools that allow individual manipulation of each neuron. By contrast, standardized behavioral assays that are commonly used to analyze learning and memory in Drosophila larvae exhibit no such technical development. Most commonly, a simple assay with Petri dishes and odor containers is used; in this method, the animals must be manually transferred in several steps. The behavioral approach is therefore labor-intensive and limits the capacity to conduct large-scale genetic screenings in small laboratories. To circumvent these limitations, we introduce a training device called the Maggot Instructor. This device allows automatic training up to 10 groups of larvae in parallel. To achieve such goal, we used fully automated, computer-controlled optogenetic activation of single olfactory neurons in combination with the application of electric shocks. We showed that Drosophila larvae trained with the Maggot Instructor establish an odor-specific memory, which is independent of handling and non-associative effects. The Maggot Instructor will allow to investigate the large collections of genetically modified larvae in a short period and with minimal human resources. Therefore, the Maggot Instructor should be able to help extensive behavioral experiments in Drosophila larvae to keep up with the current technical advancements. In the longer term, this condition will lead to a better understanding of how learning and memory are organized at the cellular, synaptic, and molecular levels in Drosophila larvae.
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Affiliation(s)
| | - Annekathrin Widmann
- Department of Biology, University of Konstanz, Konstanz, Germany.,Department of Molecular Neurobiology of Behavior, Georg-August-University Göttingen, Göttingen, Germany
| | - Andreas S Thum
- Department of Biology, University of Konstanz, Konstanz, Germany.,Department of Genetics, University of Leipzig, Leipzig, Germany
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23
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The Olfactory Logic behind Fruit Odor Preferences in Larval and Adult Drosophila. Cell Rep 2018; 23:2524-2531. [DOI: 10.1016/j.celrep.2018.04.085] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 02/22/2018] [Accepted: 04/19/2018] [Indexed: 01/22/2023] Open
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24
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Widmann A, Eichler K, Selcho M, Thum AS, Pauls D. Odor-taste learning in Drosophila larvae. JOURNAL OF INSECT PHYSIOLOGY 2018; 106:47-54. [PMID: 28823531 DOI: 10.1016/j.jinsphys.2017.08.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 08/07/2017] [Accepted: 08/16/2017] [Indexed: 06/07/2023]
Abstract
The Drosophila larva is an attractive model system to study fundamental questions in the field of neuroscience. Like the adult fly, the larva offers a seemingly unlimited genetic toolbox, which allows one to visualize, silence or activate neurons down to the single cell level. This, combined with its simplicity in terms of cell numbers, offers a useful system to study the neuronal correlates of complex processes including associative odor-taste learning and memory formation. Here, we summarize the current knowledge about odor-taste learning and memory at the behavioral level and integrate the recent progress on the larval connectome to shed light on the sub-circuits that allow Drosophila larvae to integrate present sensory input in the context of past experience and to elicit an appropriate behavioral response.
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Affiliation(s)
| | - Katharina Eichler
- Department of Biology, University of Konstanz, D-78464 Konstanz, Germany; HHMI Janelia Research Campus, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - Mareike Selcho
- Department of Neurobiology and Genetics, Theodor-Boveri-Institute, Biocenter, University of Würzburg, D-97074 Würzburg, Germany
| | - Andreas S Thum
- Department of Biology, University of Konstanz, D-78464 Konstanz, Germany; Department of Genetics, University of Leipzig, D-04103 Leipzig, Germany.
| | - Dennis Pauls
- Department of Neurobiology and Genetics, Theodor-Boveri-Institute, Biocenter, University of Würzburg, D-97074 Würzburg, Germany.
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25
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Clark DA, Kohler D, Mathis A, Slankster E, Kafle S, Odell SR, Mathew D. Tracking Drosophila Larval Behavior in Response to Optogenetic Stimulation of Olfactory Neurons. J Vis Exp 2018. [PMID: 29630041 DOI: 10.3791/57353] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
The ability of insects to navigate toward odor sources is based on the activities of their first-order olfactory receptor neurons (ORNs). While a considerable amount of information has been generated regarding ORN responses to odorants, the role of specific ORNs in driving behavioral responses remains poorly understood. Complications in behavior analyses arise due to different volatilities of odorants that activate individual ORNs, multiple ORNs activated by single odorants, and the difficulty in replicating naturally observed temporal variations in olfactory stimuli using conventional odor-delivery methods in the laboratory. Here, we describe a protocol that analyzes Drosophila larval behavior in response to simultaneous optogenetic stimulation of its ORNs. The optogenetic technology used here allows for specificity of ORN activation and precise control of temporal patterns of ORN activation. Corresponding larval movement is tracked, digitally recorded, and analyzed using custom written software. By replacing odor stimuli with light stimuli, this method allows for a more precise control of individual ORN activation in order to study its impact on larval behavior. Our method could be further extended to study the impact of second-order projection neurons (PNs) as well as local neurons (LNs) on larval behavior. This method will thus enable a comprehensive dissection of olfactory circuit function and complement studies on how olfactory neuron activities translate in to behavior responses.
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Affiliation(s)
- David A Clark
- Department of Biology, MS-0314, University of Nevada; Integrated Neuroscience Graduate Program, University of Nevada
| | | | | | | | - Samipya Kafle
- Department of Biology, MS-0314, University of Nevada
| | - Seth R Odell
- Department of Biology, MS-0314, University of Nevada; Integrated Neuroscience Graduate Program, University of Nevada
| | - Dennis Mathew
- Department of Biology, MS-0314, University of Nevada; Integrated Neuroscience Graduate Program, University of Nevada;
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26
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Transsynaptic Mapping of Second-Order Taste Neurons in Flies by trans-Tango. Neuron 2017; 96:783-795.e4. [PMID: 29107518 DOI: 10.1016/j.neuron.2017.10.011] [Citation(s) in RCA: 143] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Revised: 06/30/2017] [Accepted: 10/05/2017] [Indexed: 12/27/2022]
Abstract
Mapping neural circuits across defined synapses is essential for understanding brain function. Here we describe trans-Tango, a technique for anterograde transsynaptic circuit tracing and manipulation. At the core of trans-Tango is a synthetic signaling pathway that is introduced into all neurons in the animal. This pathway converts receptor activation at the cell surface into reporter expression through site-specific proteolysis. Specific labeling is achieved by presenting a tethered ligand at the synapses of genetically defined neurons, thereby activating the pathway in their postsynaptic partners and providing genetic access to these neurons. We first validated trans-Tango in the Drosophila olfactory system and then implemented it in the gustatory system, where projections beyond the first-order receptor neurons are not fully characterized. We identified putative second-order neurons within the sweet circuit that include projection neurons targeting known neuromodulation centers in the brain. These experiments establish trans-Tango as a flexible platform for transsynaptic circuit analysis.
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27
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Eichler K, Li F, Litwin-Kumar A, Park Y, Andrade I, Schneider-Mizell CM, Saumweber T, Huser A, Eschbach C, Gerber B, Fetter RD, Truman JW, Priebe CE, Abbott LF, Thum AS, Zlatic M, Cardona A. The complete connectome of a learning and memory centre in an insect brain. Nature 2017; 548:175-182. [PMID: 28796202 PMCID: PMC5806122 DOI: 10.1038/nature23455] [Citation(s) in RCA: 275] [Impact Index Per Article: 39.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Accepted: 07/04/2017] [Indexed: 12/19/2022]
Abstract
Associating stimuli with positive or negative reinforcement is essential for survival, but a complete wiring diagram of a higher-order circuit supporting associative memory has not been previously available. Here we reconstruct one such circuit at synaptic resolution, the Drosophila larval mushroom body. We find that most Kenyon cells integrate random combinations of inputs but that a subset receives stereotyped inputs from single projection neurons. This organization maximizes performance of a model output neuron on a stimulus discrimination task. We also report a novel canonical circuit in each mushroom body compartment with previously unidentified connections: reciprocal Kenyon cell to modulatory neuron connections, modulatory neuron to output neuron connections, and a surprisingly high number of recurrent connections between Kenyon cells. Stereotyped connections found between output neurons could enhance the selection of learned behaviours. The complete circuit map of the mushroom body should guide future functional studies of this learning and memory centre.
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Affiliation(s)
- Katharina Eichler
- Howard Hughes Medical Institute Janelia Research Campus, 19700 Helix Drive, Ashburn, Virginia 20147, USA
- Department of Biology, University of Konstanz, Universitätsstrasse 10, 78464 Konstanz, Germany
| | - Feng Li
- Howard Hughes Medical Institute Janelia Research Campus, 19700 Helix Drive, Ashburn, Virginia 20147, USA
| | - Ashok Litwin-Kumar
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Department of Neuroscience, Columbia University, 3227 Broadway, New York, New York 10027, USA
| | - Youngser Park
- Department of Applied Mathematics and Statistics, Whiting School of Engineering, Johns Hopkins University, 100 Whitehead Hall, 3400 North Charles Street, Baltimore, Maryland 21218, USA
| | - Ingrid Andrade
- Howard Hughes Medical Institute Janelia Research Campus, 19700 Helix Drive, Ashburn, Virginia 20147, USA
| | - Casey M Schneider-Mizell
- Howard Hughes Medical Institute Janelia Research Campus, 19700 Helix Drive, Ashburn, Virginia 20147, USA
| | - Timo Saumweber
- Abteilung Genetik von Lernen und Gedächtnis, Leibniz Institut für Neurobiologie, 39118 Magdeburg, Germany
| | - Annina Huser
- Department of Biology, University of Konstanz, Universitätsstrasse 10, 78464 Konstanz, Germany
| | - Claire Eschbach
- Howard Hughes Medical Institute Janelia Research Campus, 19700 Helix Drive, Ashburn, Virginia 20147, USA
| | - Bertram Gerber
- Abteilung Genetik von Lernen und Gedächtnis, Leibniz Institut für Neurobiologie, 39118 Magdeburg, Germany
- Otto von Guericke Universität Magdeburg, Institut für Biologie, Verhaltensgenetik, Universitätsplatz 2, D-39106 Magdeburg, Germany
- Otto-von-Guericke University Magdeburg, Center for Behavioral Brain Sciences, Universitätsplatz 2, D-39106 Magdeburg, Germany
| | - Richard D Fetter
- Howard Hughes Medical Institute Janelia Research Campus, 19700 Helix Drive, Ashburn, Virginia 20147, USA
| | - James W Truman
- Howard Hughes Medical Institute Janelia Research Campus, 19700 Helix Drive, Ashburn, Virginia 20147, USA
| | - Carey E Priebe
- Department of Applied Mathematics and Statistics, Whiting School of Engineering, Johns Hopkins University, 100 Whitehead Hall, 3400 North Charles Street, Baltimore, Maryland 21218, USA
| | - L F Abbott
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Department of Neuroscience, Columbia University, 3227 Broadway, New York, New York 10027, USA
- Department of Physiology and Cellular Biophysics, Columbia University, Russ Berrie Pavilion, 1150 St Nicholas Avenue, New York, New York 10032, USA
| | - Andreas S Thum
- Department of Biology, University of Konstanz, Universitätsstrasse 10, 78464 Konstanz, Germany
| | - Marta Zlatic
- Howard Hughes Medical Institute Janelia Research Campus, 19700 Helix Drive, Ashburn, Virginia 20147, USA
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK
| | - Albert Cardona
- Howard Hughes Medical Institute Janelia Research Campus, 19700 Helix Drive, Ashburn, Virginia 20147, USA
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3DY, UK
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Huser A, Eschment M, Güllü N, Collins KAN, Böpple K, Pankevych L, Rolsing E, Thum AS. Anatomy and behavioral function of serotonin receptors in Drosophila melanogaster larvae. PLoS One 2017; 12:e0181865. [PMID: 28777821 PMCID: PMC5544185 DOI: 10.1371/journal.pone.0181865] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Accepted: 07/07/2017] [Indexed: 12/21/2022] Open
Abstract
The biogenic amine serotonin (5-HT) is an important neuroactive molecule in the central nervous system of the majority of animal phyla. 5-HT binds to specific G protein-coupled and ligand-gated ion receptors to regulate particular aspects of animal behavior. In Drosophila, as in many other insects this includes the regulation of locomotion and feeding. Due to its genetic amenability and neuronal simplicity the Drosophila larva has turned into a useful model for studying the anatomical and molecular basis of chemosensory behaviors. This is particularly true for the olfactory system, which is mostly described down to the synaptic level over the first three orders of neuronal information processing. Here we focus on the 5-HT receptor system of the Drosophila larva. In a bipartite approach consisting of anatomical and behavioral experiments we describe the distribution and the implications of individual 5-HT receptors on naïve and acquired chemosensory behaviors. Our data suggest that 5-HT1A, 5-HT1B, and 5-HT7 are dispensable for larval naïve olfactory and gustatory choice behaviors as well as for appetitive and aversive associative olfactory learning and memory. In contrast, we show that 5-HT/5-HT2A signaling throughout development, but not as an acute neuronal function, affects associative olfactory learning and memory using high salt concentration as a negative unconditioned stimulus. These findings describe for the first time an involvement of 5-HT signaling in learning and memory in Drosophila larvae. In the longer run these results may uncover developmental, 5-HT dependent principles related to reinforcement processing possibly shared with adult Drosophila and other insects.
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Affiliation(s)
- Annina Huser
- Department of Biology, University of Konstanz, Konstanz, Germany
| | - Melanie Eschment
- Department of Biology, University of Konstanz, Konstanz, Germany
| | - Nazli Güllü
- Department of Biology, University of Konstanz, Konstanz, Germany
| | | | - Kathrin Böpple
- Department of Biology, University of Konstanz, Konstanz, Germany
| | - Lyubov Pankevych
- Department of Biology, University of Konstanz, Konstanz, Germany
| | - Emilia Rolsing
- Department of Biology, University of Konstanz, Konstanz, Germany
| | - Andreas S. Thum
- Department of Biology, University of Konstanz, Konstanz, Germany
- Zukunftskolleg, University of Konstanz, Konstanz, Germany
- Department of Genetics, University of Leipzig, Leipzig, Germany
- * E-mail:
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29
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Minocha S, Boll W, Noll M. Crucial roles of Pox neuro in the developing ellipsoid body and antennal lobes of the Drosophila brain. PLoS One 2017; 12:e0176002. [PMID: 28441464 PMCID: PMC5404782 DOI: 10.1371/journal.pone.0176002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Accepted: 04/04/2017] [Indexed: 01/18/2023] Open
Abstract
The paired box gene Pox neuro (Poxn) is expressed in two bilaterally symmetric neuronal clusters of the developing adult Drosophila brain, a protocerebral dorsal cluster (DC) and a deutocerebral ventral cluster (VC). We show that all cells that express Poxn in the developing brain are postmitotic neurons. During embryogenesis, the DC and VC consist of only 20 and 12 neurons that express Poxn, designated embryonic Poxn-neurons. The number of Poxn-neurons increases only during the third larval instar, when the DC and VC increase dramatically to about 242 and 109 Poxn-neurons, respectively, virtually all of which survive to the adult stage, while no new Poxn-neurons are added during metamorphosis. Although the vast majority of Poxn-neurons express Poxn only during third instar, about half of them are born by the end of embryogenesis, as demonstrated by the absence of BrdU incorporation during larval stages. At late third instar, embryonic Poxn-neurons, which begin to express Poxn during embryogenesis, can be easily distinguished from embryonic-born and larval-born Poxn-neurons, which begin to express Poxn only during third instar, (i) by the absence of Pros, (ii) their overt differentiation of axons and neurites, and (iii) the strikingly larger diameter of their cell bodies still apparent in the adult brain. The embryonic Poxn-neurons are primary neurons that lay out the pioneering tracts for the secondary Poxn-neurons, which differentiate projections and axons that follow those of the primary neurons during metamorphosis. The DC and the VC participate only in two neuropils of the adult brain. The DC forms most, if not all, of the neurons that connect the bulb (lateral triangle) with the ellipsoid body, a prominent neuropil of the central complex, while the VC forms most of the ventral projection neurons of the antennal lobe, which connect it ipsilaterally to the lateral horn, bypassing the mushroom bodies. In addition, Poxn-neurons of the VC are ventral local interneurons of the antennal lobe. In the absence of Poxn protein in the developing brain, embryonic Poxn-neurons stall their projections and cannot find their proper target neuropils, the bulb and ellipsoid body in the case of the DC, or the antennal lobe and lateral horn in the case of the VC, whereby the absence of the ellipsoid body neuropil is particularly striking. Poxn is thus crucial for pathfinding both in the DC and VC. Additional implications of our results are discussed.
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Affiliation(s)
- Shilpi Minocha
- Institute of Molecular Life Sciences, University of Zürich, Zürich, Switzerland
| | - Werner Boll
- Institute of Molecular Life Sciences, University of Zürich, Zürich, Switzerland
| | - Markus Noll
- Institute of Molecular Life Sciences, University of Zürich, Zürich, Switzerland
- * E-mail:
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30
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Lutz EK, Lahondère C, Vinauger C, Riffell JA. Olfactory learning and chemical ecology of olfaction in disease vector mosquitoes: a life history perspective. CURRENT OPINION IN INSECT SCIENCE 2017; 20:75-83. [PMID: 28602240 PMCID: PMC5492930 DOI: 10.1016/j.cois.2017.03.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Revised: 02/28/2017] [Accepted: 03/07/2017] [Indexed: 06/07/2023]
Abstract
Mosquitoes transmit many debilitating diseases including malaria, dengue and Zika. Odors mediate behaviors that directly impact disease transmission (blood-feeding) as well as life history events that contribute to mosquito survival and fitness (mating and oviposition, nectar foraging, larval foraging and predator avoidance). In addition to innate olfaction-mediated behaviors, mosquitoes rely on olfactory experience throughout their life to inform advantageous choices in many of these important behaviors. Previous reviews have addressed either the chemical ecology of mosquitoes, or olfactory-driven behaviors including host-feeding or oviposition. Adding to this literature, we use a holistic life history perspective to integrate and compare innate and learned olfactory behavior at various stages of mosquito development.
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Affiliation(s)
- Eleanor K Lutz
- Department of Biology, University of Washington, Seattle, WA 98195, United States
| | - Chloé Lahondère
- Department of Biology, University of Washington, Seattle, WA 98195, United States
| | - Clément Vinauger
- Department of Biology, University of Washington, Seattle, WA 98195, United States
| | - Jeffrey A Riffell
- Department of Biology, University of Washington, Seattle, WA 98195, United States.
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31
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Barish S, Li Q, Pan JW, Soeder C, Jones C, Volkan PC. Transcriptional profiling of olfactory system development identifies distal antenna as a regulator of subset of neuronal fates. Sci Rep 2017; 7:40873. [PMID: 28102318 PMCID: PMC5244397 DOI: 10.1038/srep40873] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 12/13/2016] [Indexed: 01/22/2023] Open
Abstract
Drosophila uses 50 different olfactory receptor neuron (ORN) classes that are clustered within distinct sensilla subtypes to decipher their chemical environment. Each sensilla subtype houses 1-4 ORN identities that arise through asymmetric divisions of a single sensory organ precursor (SOP). Despite a number of mutational studies investigating the regulation of ORN development, a majority of the transcriptional programs that lead to the different ORN classes in the developing olfactory system are unknown. Here we use transcriptional profiling across the time series of antennal development to identify novel transcriptional programs governing the differentiation of ORNs. We surveyed four critical developmental stages of the olfactory system: 3rd instar larval (prepatterning), 8 hours after puparium formation (APF, SOP selection), 40 hrs APF (neurogenesis), and adult antennae. We focused on the expression profiles of olfactory receptor genes and transcription factors-the two main classes of genes that regulate the sensory identity of ORNs. We identify distinct clusters of genes that have overlapping temporal expression profiles suggesting they have a key role during olfactory system development. We show that the expression of the transcription factor distal antenna (dan) is highly similar to other prepatterning factors and is required for the expression of a subset of ORs.
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Affiliation(s)
- Scott Barish
- Duke University, Department of Biology, Durham, NC, USA
| | - Qingyun Li
- Duke University, Department of Biology, Durham, NC, USA
| | - Jia W. Pan
- Duke University, Department of Biology, Durham, NC, USA
| | - Charlie Soeder
- University of North Carolina- Chapel Hill, Integrative Program for Biological & Genome Sciences, Chapel Hill, NC, USA
| | - Corbin Jones
- University of North Carolina- Chapel Hill, Integrative Program for Biological & Genome Sciences, Chapel Hill, NC, USA
- University of North Carolina- Chapel Hill, Department of Biology, Chapel Hill, NC, USA
| | - Pelin C. Volkan
- Duke University, Department of Biology, Durham, NC, USA
- Duke Institute for Brain Sciences, Durham, NC, USA
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32
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Kohsaka H, Guertin PA, Nose A. Neural Circuits Underlying Fly Larval Locomotion. Curr Pharm Des 2017; 23:1722-1733. [PMID: 27928962 PMCID: PMC5470056 DOI: 10.2174/1381612822666161208120835] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 12/01/2016] [Indexed: 12/17/2022]
Abstract
Locomotion is a complex motor behavior that may be expressed in different ways using a variety of strategies depending upon species and pathological or environmental conditions. Quadrupedal or bipedal walking, running, swimming, flying and gliding constitute some of the locomotor modes enabling the body, in all cases, to move from one place to another. Despite these apparent differences in modes of locomotion, both vertebrate and invertebrate species share, at least in part, comparable neural control mechanisms for locomotor rhythm and pattern generation and modulation. Significant advances have been made in recent years in studies of the genetic aspects of these control systems. Findings made specifically using Drosophila (fruit fly) models and preparations have contributed to further understanding of the key role of genes in locomotion. This review focuses on some of the main findings made in larval fruit flies while briefly summarizing the basic advantages of using this powerful animal model for studying the neural locomotor system.
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Affiliation(s)
- Hiroshi Kohsaka
- Department of Complexity Science and Engineering, University of Tokyo, Kashiwanoha, Kashiwa, Chiba 277-8561, Japan
| | - Pierre A. Guertin
- Department of Psychiatry & Neurosciences, Laval University, Québec City, QC, Canada
| | - Akinao Nose
- Department of Complexity Science and Engineering, University of Tokyo, Kashiwanoha, Kashiwa, Chiba 277-8561, Japan
- Department of Physics, Graduate School of Science, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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33
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Clark JT, Ray A. Olfactory Mechanisms for Discovery of Odorants to Reduce Insect-Host Contact. J Chem Ecol 2016; 42:919-930. [PMID: 27628342 DOI: 10.1007/s10886-016-0770-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2016] [Revised: 08/25/2016] [Accepted: 09/08/2016] [Indexed: 11/29/2022]
Abstract
Insects have developed highly sophisticated and sensitive olfactory systems to find animal or plant hosts for feeding. Some insects vector pathogens that cause diseases in hundreds of millions of people and destroy billions of dollars of food products every year. There is great interest, therefore, in understanding how the insect olfactory system can be manipulated to reduce their contact with hosts. Here, we review recent advances in our understanding of insect olfactory detection mechanisms, which may serve as a foundation for designing insect control programs based on manipulation of their behaviors by using odorants. Because every insect species has a unique set of olfactory receptors and olfactory-mediated behaviors, we focus primarily on general principles of odor detection that potentially apply to most insects. While these mechanisms have emerged from studies on model systems for study of insect olfaction, such as Drosophila melanogaster, they provide a foundation for discovery of odorants to repel vector insects or reduce their host-seeking behavior.
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Affiliation(s)
- Jonathan T Clark
- Interdepartmental Neuroscience Program, University of California, Riverside, CA, 92521, USA
| | - Anandasankar Ray
- Interdepartmental Neuroscience Program, University of California, Riverside, CA, 92521, USA. .,Entomology Department, University of California, Riverside, CA, 92521, USA. .,Center for Disease Vector Research, University of California, Riverside, CA, 92521, USA.
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34
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Differential Contributions of Olfactory Receptor Neurons in a Drosophila Olfactory Circuit. eNeuro 2016; 3:eN-NWR-0045-16. [PMID: 27570823 PMCID: PMC4987412 DOI: 10.1523/eneuro.0045-16.2016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 07/11/2016] [Accepted: 07/13/2016] [Indexed: 01/02/2023] Open
Abstract
The ability of an animal to detect, discriminate, and respond to odors depends on the functions of its olfactory receptor neurons (ORNs). The extent to which each ORN, upon activation, contributes to chemotaxis is not well understood. We hypothesized that strong activation of each ORN elicits a different behavioral response in the Drosophila melanogaster larva by differentially affecting the composition of its navigational behavior. To test this hypothesis, we exposed Drosophila larvae to specific odorants to analyze the effect of individual ORN activity on chemotaxis. We used two different behavioral paradigms to analyze the chemotaxis response of larvae to odorants. When tested with five different odorants that elicit strong physiological responses from single ORNs, larval behavioral responses toward each odorant differed in the strength of attraction as well as in the composition of discrete navigational elements, such as runs and turns. Further, behavioral responses to odorants did not correlate with either the strength of odor gradients tested or the sensitivity of each ORN to its cognate odorant. Finally, we provide evidence that wild-type larvae with all ORNs intact exhibit higher behavioral variance than mutant larvae that have only a single pair of functional ORNs. We conclude that individual ORNs contribute differently to the olfactory circuit that instructs chemotactic responses. Our results, along with recent studies from other groups, suggest that ORNs are functionally nonequivalent units. These results have implications for understanding peripheral odor coding.
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35
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Berck ME, Khandelwal A, Claus L, Hernandez-Nunez L, Si G, Tabone CJ, Li F, Truman JW, Fetter RD, Louis M, Samuel AD, Cardona A. The wiring diagram of a glomerular olfactory system. eLife 2016; 5. [PMID: 27177418 PMCID: PMC4930330 DOI: 10.7554/elife.14859] [Citation(s) in RCA: 116] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2016] [Accepted: 05/06/2016] [Indexed: 12/12/2022] Open
Abstract
The sense of smell enables animals to react to long-distance cues according to learned and innate valences. Here, we have mapped with electron microscopy the complete wiring diagram of the Drosophila larval antennal lobe, an olfactory neuropil similar to the vertebrate olfactory bulb. We found a canonical circuit with uniglomerular projection neurons (uPNs) relaying gain-controlled ORN activity to the mushroom body and the lateral horn. A second, parallel circuit with multiglomerular projection neurons (mPNs) and hierarchically connected local neurons (LNs) selectively integrates multiple ORN signals already at the first synapse. LN-LN synaptic connections putatively implement a bistable gain control mechanism that either computes odor saliency through panglomerular inhibition, or allows some glomeruli to respond to faint aversive odors in the presence of strong appetitive odors. This complete wiring diagram will support experimental and theoretical studies towards bridging the gap between circuits and behavior. DOI:http://dx.doi.org/10.7554/eLife.14859.001 Our sense of smell can tell us about bread being baked faraway in the kitchen, or whether a leftover piece finally went bad. Similarly to the eyes, the nose enables us to make up a mental image of what lies at a distance. In mammals, the surface of the nose hosts a huge number of olfactory sensory cells, each of which is tuned to respond to a small set of scent molecules. The olfactory sensory cells communicate with a region of the brain called the olfactory bulb. Olfactory sensory cells of the same type converge onto the same small pocket of the olfactory bulb, forming a structure called a glomerulus. Similarly to how the retina generates an image, the combined activity of multiple glomeruli defines an odor. A particular smell is the combination of many volatile compounds, the odorants. Therefore the interactions between different olfactory glomeruli are important for defining the nature of the perceived odor. Although the types of neurons involved in these interactions were known in insects, fish and mice, a precise wiring diagram of a complete set of glomeruli had not been described. In particular, the points of contact through which neurons communicate with each other – known as synapses – among all the neurons participating in an olfactory system were not known. Berck, Khandelwal et al. have now taken advantage of the small size of the olfactory system of the larvae of Drosophila fruit flies to fully describe, using high-resolution imaging, all its neurons and their synapses. The results define the complete wiring diagram of the neural circuit that processes the signals sent by olfactory sensory neurons in the larva’s olfactory circuits. In addition to the neurons that read out the activity of a single glomerulus and send it to higher areas of the brain for further processing, there are also numerous neurons that read out activity from multiple glomeruli. These neurons represent a system, encoded in the genome, for quickly extracting valuable olfactory information and then relaying it to other areas of the brain. An essential aspect of sensation is the ability to stop noticing a stimulus if it doesn't change. This allows an animal to, for example, find food by moving in a direction that increases the intensity of an odor. Inhibition mediates some aspects of this capability. The discovery of structure in the inhibitory connections among glomeruli, together with prior findings on the inner workings of the olfactory system, enabled Berck, Khandelwal et al. to hypothesize how the olfactory circuits enable odor gradients to be navigated. Further investigation revealed more about how the circuits could detect slight changes in odor concentration regardless of whether the overall odor intensity is strong or faint. And, crucially, it revealed how the worst odors – which can signal danger – can still be perceived in the presence of very strong pleasant odors. With the wiring diagram, theories about the sense of smell can now be tested using the genetic tools available for Drosophila, leading to an understanding of how neural circuits work. DOI:http://dx.doi.org/10.7554/eLife.14859.002
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Affiliation(s)
- Matthew E Berck
- Department of Physics, Harvard University, Cambridge, United States.,Center for Brain Science, Harvard University, Cambridge, United States
| | - Avinash Khandelwal
- EMBL-CRG Systems Biology Program, Centre for Genomic Regulation, The Barcelona Institute of Science and Technology, Barcelona, Spain.,Universitat Pompeu Fabra, Barcelona, Spain
| | - Lindsey Claus
- Department of Physics, Harvard University, Cambridge, United States.,Center for Brain Science, Harvard University, Cambridge, United States
| | - Luis Hernandez-Nunez
- Department of Physics, Harvard University, Cambridge, United States.,Center for Brain Science, Harvard University, Cambridge, United States
| | - Guangwei Si
- Department of Physics, Harvard University, Cambridge, United States.,Center for Brain Science, Harvard University, Cambridge, United States
| | | | - Feng Li
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - James W Truman
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Rick D Fetter
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Matthieu Louis
- EMBL-CRG Systems Biology Program, Centre for Genomic Regulation, The Barcelona Institute of Science and Technology, Barcelona, Spain.,Universitat Pompeu Fabra, Barcelona, Spain
| | - Aravinthan Dt Samuel
- Department of Physics, Harvard University, Cambridge, United States.,Center for Brain Science, Harvard University, Cambridge, United States
| | - Albert Cardona
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
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36
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Changes Across Development Influence Visible and Cryptic Natural Variation of Drosophila melanogaster Olfactory Response. Evol Biol 2015. [DOI: 10.1007/s11692-015-9352-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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37
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Apostolopoulou AA, Rist A, Thum AS. Taste processing in Drosophila larvae. Front Integr Neurosci 2015; 9:50. [PMID: 26528147 PMCID: PMC4602287 DOI: 10.3389/fnint.2015.00050] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 09/25/2015] [Indexed: 02/04/2023] Open
Abstract
The sense of taste allows animals to detect chemical substances in their environment to initiate appropriate behaviors: to find food or a mate, to avoid hostile environments and predators. Drosophila larvae are a promising model organism to study gustation. Their simple nervous system triggers stereotypic behavioral responses, and the coding of taste can be studied by genetic tools at the single cell level. This review briefly summarizes recent progress on how taste information is sensed and processed by larval cephalic and pharyngeal sense organs. The focus lies on several studies, which revealed cellular and molecular mechanisms required to process sugar, salt, and bitter substances.
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Affiliation(s)
| | - Anna Rist
- Department of Biology, University of Konstanz Konstanz, Germany
| | - Andreas S Thum
- Department of Biology, University of Konstanz Konstanz, Germany ; Zukunftskolleg, University of Konstanz Konstanz, Germany
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38
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Rohwedder A, Selcho M, Chassot B, Thum AS. Neuropeptide F neurons modulate sugar reward during associative olfactory learning ofDrosophilalarvae. J Comp Neurol 2015; 523:2637-64. [DOI: 10.1002/cne.23873] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Revised: 07/19/2015] [Accepted: 07/28/2015] [Indexed: 01/29/2023]
Affiliation(s)
- Astrid Rohwedder
- Department of Biology; University of Fribourg; Fribourg Switzerland
| | - Mareike Selcho
- Department of Neurobiology and Genetics, Theodor-Boveri-Institute, Biocenter; University of Würzburg; Würzburg Germany
| | - Bérénice Chassot
- Department of Biology; University of Fribourg; Fribourg Switzerland
| | - Andreas S. Thum
- Department of Biology; University of Fribourg; Fribourg Switzerland
- Department of Biology; University of Konstanz; Konstanz Germany
- Zukunftskolleg; University of Konstanz; Konstanz Germany
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39
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Hartenstein V, Younossi-Hartenstein A, Lovick JK, Kong A, Omoto JJ, Ngo KT, Viktorin G. Lineage-associated tracts defining the anatomy of the Drosophila first instar larval brain. Dev Biol 2015; 406:14-39. [PMID: 26141956 DOI: 10.1016/j.ydbio.2015.06.021] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Revised: 06/25/2015] [Accepted: 06/27/2015] [Indexed: 11/15/2022]
Abstract
Fixed lineages derived from unique, genetically specified neuroblasts form the anatomical building blocks of the Drosophila brain. Neurons belonging to the same lineage project their axons in a common tract, which is labeled by neuronal markers. In this paper, we present a detailed atlas of the lineage-associated tracts forming the brain of the early Drosophila larva, based on the use of global markers (anti-Neuroglian, anti-Neurotactin, inscuteable-Gal4>UAS-chRFP-Tub) and lineage-specific reporters. We describe 68 discrete fiber bundles that contain axons of one lineage or pairs/small sets of adjacent lineages. Bundles enter the neuropil at invariant locations, the lineage tract entry portals. Within the neuropil, these fiber bundles form larger fascicles that can be classified, by their main orientation, into longitudinal, transverse, and vertical (ascending/descending) fascicles. We present 3D digital models of lineage tract entry portals and neuropil fascicles, set into relationship to commonly used, easily recognizable reference structures such as the mushroom body, the antennal lobe, the optic lobe, and the Fasciclin II-positive fiber bundles that connect the brain and ventral nerve cord. Correspondences and differences between early larval tract anatomy and the previously described late larval and adult lineage patterns are highlighted. Our L1 neuro-anatomical atlas of lineages constitutes an essential step towards following morphologically defined lineages to the neuroblasts of the early embryo, which will ultimately make it possible to link the structure and connectivity of a lineage to the expression of genes in the particular neuroblast that gives rise to that lineage. Furthermore, the L1 atlas will be important for a host of ongoing work that attempts to reconstruct neuronal connectivity at the level of resolution of single neurons and their synapses.
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Affiliation(s)
- Volker Hartenstein
- Department of Molecular Cell and Developmental Biology, University of California, Los Angeles, 610 Charles E. Young Drive, 5009 Terasaki Life Sciences Building, Los Angeles, CA 90095, USA.
| | - Amelia Younossi-Hartenstein
- Department of Molecular Cell and Developmental Biology, University of California, Los Angeles, 610 Charles E. Young Drive, 5009 Terasaki Life Sciences Building, Los Angeles, CA 90095, USA
| | - Jennifer K Lovick
- Department of Molecular Cell and Developmental Biology, University of California, Los Angeles, 610 Charles E. Young Drive, 5009 Terasaki Life Sciences Building, Los Angeles, CA 90095, USA
| | - Angel Kong
- Department of Molecular Cell and Developmental Biology, University of California, Los Angeles, 610 Charles E. Young Drive, 5009 Terasaki Life Sciences Building, Los Angeles, CA 90095, USA
| | - Jaison J Omoto
- Department of Molecular Cell and Developmental Biology, University of California, Los Angeles, 610 Charles E. Young Drive, 5009 Terasaki Life Sciences Building, Los Angeles, CA 90095, USA
| | - Kathy T Ngo
- Department of Molecular Cell and Developmental Biology, University of California, Los Angeles, 610 Charles E. Young Drive, 5009 Terasaki Life Sciences Building, Los Angeles, CA 90095, USA
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40
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Schulze A, Gomez-Marin A, Rajendran VG, Lott G, Musy M, Ahammad P, Deogade A, Sharpe J, Riedl J, Jarriault D, Trautman ET, Werner C, Venkadesan M, Druckmann S, Jayaraman V, Louis M. Dynamical feature extraction at the sensory periphery guides chemotaxis. eLife 2015; 4. [PMID: 26077825 PMCID: PMC4468351 DOI: 10.7554/elife.06694] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 05/30/2015] [Indexed: 11/13/2022] Open
Abstract
Behavioral strategies employed for chemotaxis have been described across phyla, but the sensorimotor basis of this phenomenon has seldom been studied in naturalistic contexts. Here, we examine how signals experienced during free olfactory behaviors are processed by first-order olfactory sensory neurons (OSNs) of the Drosophila larva. We find that OSNs can act as differentiators that transiently normalize stimulus intensity—a property potentially derived from a combination of integral feedback and feed-forward regulation of olfactory transduction. In olfactory virtual reality experiments, we report that high activity levels of the OSN suppress turning, whereas low activity levels facilitate turning. Using a generalized linear model, we explain how peripheral encoding of olfactory stimuli modulates the probability of switching from a run to a turn. Our work clarifies the link between computations carried out at the sensory periphery and action selection underlying navigation in odor gradients. DOI:http://dx.doi.org/10.7554/eLife.06694.001 Fruit flies are attracted to the smell of rotting fruit, and use it to guide them to nearby food sources. However, this task is made more challenging by the fact that the distribution of scent or odor molecules in the air is constantly changing. Fruit flies therefore need to cope with, and exploit, this variation if they are to use odors as cues. Odor molecules bind to receptors on the surface of nerve cells called olfactory sensory neurons, and trigger nerve impulses that travel along these cells. While many studies have investigated how fruit flies can distinguish between different odors, less is known about how animals can use variation in the strength of an odor to guide them towards its source. Optogenetics is a technique that allows neuroscientists to control the activities of individual nerve cells, simply by shining light on to them. Because fruit fly larvae are almost transparent, optogenetics can be used on freely moving animals. Now, Schulze, Gomez-Marin et al. have used optogenetics in these larvae to trigger patterns of activity in individual olfactory sensory neurons that mimic the activity patterns elicited by real odors. These virtual realities were then used to study, in detail, some of the principles that control the sensory navigation of a larva—as it moves using a series of forward ‘runs’ and direction-changing ‘turns’. Olfactory sensory neurons responded most strongly whenever light levels changed rapidly in strength (which simulated a rapid change in odor concentration). On the other hand, these neurons showed relatively little response to constant light levels (i.e., constant odors). This indicates that the activity of olfactory sensory neurons typically represents the rate of change in the concentration of an odor. An independent study by Kim et al. found that olfactory sensory neurons in adult fruit flies also respond in a similar way. Schulze, Gomez-Marin et al. went on to show that the signals processed by a single type of olfactory sensory neuron could be used to predict a larva's behavior. Larvae tended to turn less when their olfactory sensory neurons were highly active. Low levels and inhibition of activity in the olfactory sensory neurons had the opposite effect; this promoted turning. It remains to be determined how this relatively simple control principle is implemented by the neural circuits that connect sensory neurons to the parts of a larva's nervous system that are involved with movement. DOI:http://dx.doi.org/10.7554/eLife.06694.002
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Affiliation(s)
- Aljoscha Schulze
- EMBL-CRG Systems Biology Program, Centre for Genomic Regulation, Barcelona, Spain
| | - Alex Gomez-Marin
- EMBL-CRG Systems Biology Program, Centre for Genomic Regulation, Barcelona, Spain
| | - Vani G Rajendran
- EMBL-CRG Systems Biology Program, Centre for Genomic Regulation, Barcelona, Spain
| | - Gus Lott
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Marco Musy
- EMBL-CRG Systems Biology Program, Centre for Genomic Regulation, Barcelona, Spain
| | - Parvez Ahammad
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Ajinkya Deogade
- EMBL-CRG Systems Biology Program, Centre for Genomic Regulation, Barcelona, Spain
| | - James Sharpe
- EMBL-CRG Systems Biology Program, Centre for Genomic Regulation, Barcelona, Spain
| | - Julia Riedl
- EMBL-CRG Systems Biology Program, Centre for Genomic Regulation, Barcelona, Spain
| | - David Jarriault
- EMBL-CRG Systems Biology Program, Centre for Genomic Regulation, Barcelona, Spain
| | - Eric T Trautman
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Christopher Werner
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Madhusudhan Venkadesan
- Department of Mechanical Engineering and Materials Science, Yale University, New Haven, United States
| | - Shaul Druckmann
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Vivek Jayaraman
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Matthieu Louis
- EMBL-CRG Systems Biology Program, Centre for Genomic Regulation, Barcelona, Spain
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Lovick JK, Hartenstein V. Hydroxyurea-mediated neuroblast ablation establishes birth dates of secondary lineages and addresses neuronal interactions in the developing Drosophila brain. Dev Biol 2015; 402:32-47. [PMID: 25773365 PMCID: PMC4472457 DOI: 10.1016/j.ydbio.2015.03.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Revised: 02/27/2015] [Accepted: 03/05/2015] [Indexed: 11/27/2022]
Abstract
The Drosophila brain is comprised of neurons formed by approximately 100 lineages, each of which is derived from a stereotyped, asymmetrically dividing neuroblast. Lineages serve as structural and developmental units of Drosophila brain anatomy and reconstruction of lineage projection patterns represents a suitable map of Drosophila brain circuitry at the level of neuron populations ("macro-circuitry"). Two phases of neuroblast proliferation, the first in the embryo and the second during the larval phase (following a period of mitotic quiescence), produce primary and secondary lineages, respectively. Using temporally controlled pulses of hydroxyurea (HU) to ablate neuroblasts and their corresponding secondary lineages during the larval phase, we analyzed the effect on development of primary and secondary lineages in the late larval and adult brain. Our findings indicate that timing of neuroblast re-activation is highly stereotyped, allowing us to establish "birth dates" for all secondary lineages. Furthermore, our results demonstrate that, whereas the trajectory and projection pattern of primary and secondary lineages is established in a largely independent manner, the final branching pattern of secondary neurons is dependent upon the presence of appropriate neuronal targets. Taken together, our data provide new insights into the degree of neuronal plasticity during Drosophila brain development.
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Affiliation(s)
- Jennifer K Lovick
- Department of Molecular Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Volker Hartenstein
- Department of Molecular Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA.
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42
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Nehrkorn J, Tanimoto H, Herz AVM, Yarali A. A model for non-monotonic intensity coding. ROYAL SOCIETY OPEN SCIENCE 2015; 2:150120. [PMID: 26064666 PMCID: PMC4453257 DOI: 10.1098/rsos.150120] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Accepted: 04/09/2015] [Indexed: 05/12/2023]
Abstract
Peripheral neurons of most sensory systems increase their response with increasing stimulus intensity. Behavioural responses, however, can be specific to some intermediate intensity level whose particular value might be innate or associatively learned. Learning such a preference requires an adjustable trans- formation from a monotonic stimulus representation at the sensory periphery to a non-monotonic representation for the motor command. How do neural systems accomplish this task? We tackle this general question focusing on odour-intensity learning in the fruit fly, whose first- and second-order olfactory neurons show monotonic stimulus-response curves. Nevertheless, flies form associative memories specific to particular trained odour intensities. Thus, downstream of the first two olfactory processing layers, odour intensity must be re-coded to enable intensity-specific associative learning. We present a minimal, feed-forward, three-layer circuit, which implements the required transformation by combining excitation, inhibition, and, as a decisive third element, homeostatic plasticity. Key features of this circuit motif are consistent with the known architecture and physiology of the fly olfactory system, whereas alternative mechanisms are either not composed of simple, scalable building blocks or not compatible with physiological observations. The simplicity of the circuit and the robustness of its function under parameter changes make this computational motif an attractive candidate for tuneable non-monotonic intensity coding.
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Affiliation(s)
- Johannes Nehrkorn
- Department of Biology II, Bernstein Center for Computational Neuroscience Munich and Graduate School of Systemic Neurosciences, Ludwig-Maximilians-Universität München, Martinsried 82152, Germany
- Max Planck Institute of Neurobiology, Martinsried 82152, Germany
| | - Hiromu Tanimoto
- Max Planck Institute of Neurobiology, Martinsried 82152, Germany
- Tohoku University Graduate School of Life Sciences, Sendai 980-8577, Japan
| | - Andreas V. M. Herz
- Department of Biology II, Bernstein Center for Computational Neuroscience Munich and Graduate School of Systemic Neurosciences, Ludwig-Maximilians-Universität München, Martinsried 82152, Germany
- Authors for correspondence: Andreas V. M. Herz e-mail:
| | - Ayse Yarali
- Max Planck Institute of Neurobiology, Martinsried 82152, Germany
- Research Group Molecular Systems Biology of Learning, Leibniz Institute for Neurobiology, Magdeburg 39118, Germany
- Center for Brain and Behavioural Sciences, Magdeburg, Germany
- Authors for correspondence: Ayse Yarali e-mail:
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43
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Bose C, Basu S, Das N, Khurana S. Chemosensory apparatus of Drosophila larvae. Bioinformation 2015; 11:185-8. [PMID: 26124558 PMCID: PMC4479052 DOI: 10.6026/97320630011185] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Accepted: 02/26/2015] [Indexed: 02/08/2023] Open
Abstract
Many insects, including Drosophila melanogaster, have a rich repertoire of olfactory behavior. Combination of robust behavioral assays, physiological and molecular tools render D. melanogaster as highly suitable system for olfactory studies. The small number of neurons in the olfactory system of fruit flies, especially the number of sensory neurons in the larval stage, makes the exploration of sensory coding at all stages of its nervous system a potentially tractable goal, which is not possible in the foreseeable future in any mammalian preparation. Advances in physiological recordings, olfactory signaling and detailed analysis of behavior, can place larvae in a position to ask previously unanswerable questions.
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Affiliation(s)
| | | | - Nabajit Das
- Indian Institute of Science Education and Research Kolkata (IISER-K), Mohanpur, West Bengal – 741246, India
- Authors equally contributed
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44
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Abstract
Chemotaxis is important for the survival of most animals. How the brain translates sensory input into motor output beyond higher olfactory processing centers is largely unknown. We describe a group of excitatory neurons, termed Odd neurons, which are important for Drosophila larval chemotaxis. Odd neurons receive synaptic input from projection neurons in the calyx of the mushroom body and project axons to the central brain. Functional imaging shows that some of the Odd neurons respond to odor. Larvae in which Odd neurons are silenced are less efficient at odor tracking than controls and sample the odor space more frequently. Larvae in which the excitability of Odd neurons is increased are better at odor intensity discrimination and odor tracking. Thus, the Odd neurons represent a distinct pathway that regulates the sensitivity of the olfactory system to odor concentrations, demonstrating that efficient chemotaxis depends on processing of odor strength downstream of higher olfactory centers.
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45
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Grewal JS, Nguyen C, Robles R, Cho C, Kir K, Fledderman N, Gacharna G, Wesolowski M, Klinger C, Vallejo P, Menhennett L, Nagaraj A, Ebo C, Peacy G, Davelis E, Kucher D, Giers S, Kreher SA. Complex and non-redundant signals from individual odor receptors that underlie chemotaxis behavior in Drosophila melanogaster larvae. Biol Open 2014; 3:947-57. [PMID: 25238759 PMCID: PMC4197443 DOI: 10.1242/bio.20148573] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The rules by which odor receptors encode odors and allow behavior are still largely unexplored. Although large data sets of electrophysiological responses of receptors to odors have been generated, few hypotheses have been tested with behavioral assays. We use a data set on odor responses of Drosophila larval odor receptors coupled with chemotaxis behavioral assays to examine rules of odor coding. Using mutants of odor receptors, we have found that odor receptors with similar electrophysiological responses to odors across concentrations play non-redundant roles in odor coding at specific odor concentrations. We have also found that high affinity receptors for odors determine behavioral response thresholds, but the rules for determining peak behavioral responses are more complex. While receptor mutants typically show loss of attraction to odors, some receptor mutants result in increased attraction at specific odor concentrations. The odor receptor mutants were rescued using transgenic expression of odor receptors, validating assignment of phenotypes to the alleles. Vapor pressures alone cannot fully explain behavior in our assay. Finally, some odors that did not elicit strong electrophysiological responses are associated with behavioral phenotypes upon examination of odor receptor mutants. This result is consistent with the role of sensory neurons in lateral inhibition via local interneurons in the antennal lobe. Taken together, our results suggest a complexity of odor coding rules even in a simple olfactory sensory system.
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Affiliation(s)
- Jeewanjot S Grewal
- Department of Biological Sciences, Dominican University, 7900 West Division Street, Parmer Hall 244, River Forest, IL 60305, USA
| | - Christine Nguyen
- Department of Biological Sciences, Dominican University, 7900 West Division Street, Parmer Hall 244, River Forest, IL 60305, USA
| | - Raquel Robles
- Department of Biological Sciences, Dominican University, 7900 West Division Street, Parmer Hall 244, River Forest, IL 60305, USA
| | - Christina Cho
- Department of Biological Sciences, Dominican University, 7900 West Division Street, Parmer Hall 244, River Forest, IL 60305, USA
| | - Karolina Kir
- Department of Biological Sciences, Dominican University, 7900 West Division Street, Parmer Hall 244, River Forest, IL 60305, USA
| | - Nicole Fledderman
- Department of Biological Sciences, Dominican University, 7900 West Division Street, Parmer Hall 244, River Forest, IL 60305, USA
| | - George Gacharna
- Department of Biological Sciences, Dominican University, 7900 West Division Street, Parmer Hall 244, River Forest, IL 60305, USA
| | - Michael Wesolowski
- Department of Biological Sciences, Dominican University, 7900 West Division Street, Parmer Hall 244, River Forest, IL 60305, USA
| | - Christie Klinger
- Department of Biological Sciences, Dominican University, 7900 West Division Street, Parmer Hall 244, River Forest, IL 60305, USA
| | - Pedro Vallejo
- Department of Biological Sciences, Dominican University, 7900 West Division Street, Parmer Hall 244, River Forest, IL 60305, USA
| | - Lorien Menhennett
- Department of Biological Sciences, Dominican University, 7900 West Division Street, Parmer Hall 244, River Forest, IL 60305, USA
| | - Abhiram Nagaraj
- Department of Biological Sciences, Dominican University, 7900 West Division Street, Parmer Hall 244, River Forest, IL 60305, USA
| | - Chineze Ebo
- Department of Biological Sciences, Dominican University, 7900 West Division Street, Parmer Hall 244, River Forest, IL 60305, USA
| | - Garrett Peacy
- Department of Biological Sciences, Dominican University, 7900 West Division Street, Parmer Hall 244, River Forest, IL 60305, USA
| | - Eftihia Davelis
- Department of Biological Sciences, Dominican University, 7900 West Division Street, Parmer Hall 244, River Forest, IL 60305, USA
| | - David Kucher
- Department of Biological Sciences, Dominican University, 7900 West Division Street, Parmer Hall 244, River Forest, IL 60305, USA
| | - Sarah Giers
- Department of Biological Sciences, Dominican University, 7900 West Division Street, Parmer Hall 244, River Forest, IL 60305, USA
| | - Scott A Kreher
- Department of Biological Sciences, Dominican University, 7900 West Division Street, Parmer Hall 244, River Forest, IL 60305, USA
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46
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Engsontia P, Sangket U, Chotigeat W, Satasook C. Molecular evolution of the odorant and gustatory receptor genes in lepidopteran insects: implications for their adaptation and speciation. J Mol Evol 2014; 79:21-39. [PMID: 25038840 DOI: 10.1007/s00239-014-9633-0] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Accepted: 07/06/2014] [Indexed: 12/22/2022]
Abstract
Lepidoptera (comprised of butterflies and moths) is one of the largest groups of insects, including more than 160,000 described species. Chemoreception plays important roles in the adaptation of these species to a wide range of niches, e.g., plant hosts, egg-laying sites, and mates. This study investigated the molecular evolution of the lepidopteran odorant (Or) and gustatory receptor (Gr) genes using recently identified genes from Bombyx mori, Danaus plexippus, Heliconius melpomene, Plutella xylostella, Heliothis virescens, Manduca sexta, Cydia pomonella, and Spodoptera littoralis. A limited number of cases of large lineage-specific gene expansion are observed (except in the P. xylostella lineage), possibly due to selection against tandem gene duplication. There has been strong purifying selection during the evolution of both lepidopteran odorant and gustatory genes, as shown by the low ω values estimated through CodeML analysis, ranging from 0.0093 to 0.3926. However, purifying selection has been relaxed on some amino acid sites in these receptors, leading to sequence divergence, which is a precursor of positive selection on these sequences. Signatures of positive selection were detected only in a few loci from the lineage-specific analysis. Estimation of gene gains and losses suggests that the common ancestor of the Lepidoptera had fewer Or genes compared to extant species and an even more reduced number of Gr genes, particularly within the bitter receptor clade. Multiple gene gains and a few gene losses occurred during the evolution of Lepidoptera. Gene family expansion may be associated with the adaptation of lepidopteran species to plant hosts, especially after angiosperm radiation. Phylogenetic analysis of the moth sex pheromone receptor genes suggested that chromosomal translocations have occurred several times. New sex pheromone receptors have arisen through tandem gene duplication. Positive selection was detected at some amino acid sites predicted to be in the extracellular and transmembrane regions of the newly duplicated genes, which might be associated with the evolution of the new pheromone receptors.
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Affiliation(s)
- Patamarerk Engsontia
- Department of Biology, Faculty of Science, Prince of Songkla University, Songkla, 90112, Thailand,
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47
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Masuda-Nakagawa LM, Ito K, Awasaki T, O'Kane CJ. A single GABAergic neuron mediates feedback of odor-evoked signals in the mushroom body of larval Drosophila. Front Neural Circuits 2014; 8:35. [PMID: 24782716 PMCID: PMC3988396 DOI: 10.3389/fncir.2014.00035] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2014] [Accepted: 03/23/2014] [Indexed: 11/13/2022] Open
Abstract
Inhibition has a central role in defining the selectivity of the responses of higher order neurons to sensory stimuli. However, the circuit mechanisms of regulation of these responses by inhibitory neurons are still unclear. In Drosophila, the mushroom bodies (MBs) are necessary for olfactory memory, and by implication for the selectivity of learned responses to specific odors. To understand the circuitry of inhibition in the calyx (the input dendritic region) of the MBs, and its relationship with MB excitatory activity, we used the simple anatomy of the Drosophila larval olfactory system to identify any inhibitory inputs that could contribute to the selectivity of MB odor responses. We found that a single neuron accounts for all detectable GABA innervation in the calyx of the MBs, and that this neuron has pre-synaptic terminals in the calyx and post-synaptic branches in the MB lobes (output axonal area). We call this neuron the larval anterior paired lateral (APL) neuron, because of its similarity to the previously described adult APL neuron. Reconstitution of GFP partners (GRASP) suggests that the larval APL makes extensive contacts with the MB intrinsic neurons, Kenyon Cells (KCs), but few contacts with incoming projection neurons (PNs). Using calcium imaging of neuronal activity in live larvae, we show that the larval APL responds to odors, in a manner that requires output from KCs. Our data suggest that the larval APL is the sole GABAergic neuron that innervates the MB input region and carries inhibitory feedback from the MB output region, consistent with a role in modulating the olfactory selectivity of MB neurons.
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Affiliation(s)
| | - Kei Ito
- Institute of Molecular and Cellular Biosciences, The University of Tokyo Tokyo, Japan
| | - Takeshi Awasaki
- Institute of Molecular and Cellular Biosciences, The University of Tokyo Tokyo, Japan
| | - Cahir J O'Kane
- Department of Genetics, University of Cambridge Cambridge, UK
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48
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Apostolopoulou AA, Hersperger F, Mazija L, Widmann A, Wüst A, Thum AS. Composition of agarose substrate affects behavioral output of Drosophila larvae. Front Behav Neurosci 2014; 8:11. [PMID: 24478658 PMCID: PMC3904111 DOI: 10.3389/fnbeh.2014.00011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Accepted: 01/08/2014] [Indexed: 11/17/2022] Open
Abstract
In the last decade the Drosophila larva has evolved into a simple model organism offering the opportunity to integrate molecular genetics with systems neuroscience. This led to a detailed understanding of the neuronal networks for a number of sensory functions and behaviors including olfaction, vision, gustation and learning and memory. Typically, behavioral assays in use exploit simple Petri dish setups with either agarose or agar as a substrate. However, neither the quality nor the concentration of the substrate is generally standardized across these experiments and there is no data available on how larval behavior is affected by such different substrates. Here, we have investigated the effects of different agarose concentrations on several larval behaviors. We demonstrate that agarose concentration is an important parameter, which affects all behaviors tested: preference, feeding, learning and locomotion. Larvae can discriminate between different agarose concentrations, they feed differently on them, they can learn to associate an agarose concentration with an odor stimulus and change locomotion on a substrate of higher agarose concentration. Additionally, we have investigated the effect of agarose concentration on three quinine based behaviors: preference, feeding and learning. We show that in all cases examined the behavioral output changes in an agarose concentration-dependent manner. Our results suggest that comparisons between experiments performed on substrates differing in agarose concentration should be done with caution. It should be taken into consideration that the agarose concentration can affect the behavioral output and thereby the experimental outcomes per se potentially due to the initiation of an escape response or changes in foraging behavior on more rigid substrates.
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Affiliation(s)
| | | | - Lorena Mazija
- Department of Biology, University of Konstanz Konstanz, Germany
| | | | - Alexander Wüst
- Department of Biology, University of Konstanz Konstanz, Germany
| | - Andreas S Thum
- Department of Biology, University of Konstanz Konstanz, Germany
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49
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Apostolopoulou AA, Mazija L, Wüst A, Thum AS. The neuronal and molecular basis of quinine-dependent bitter taste signaling in Drosophila larvae. Front Behav Neurosci 2014; 8:6. [PMID: 24478653 PMCID: PMC3902218 DOI: 10.3389/fnbeh.2014.00006] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2013] [Accepted: 01/06/2014] [Indexed: 12/12/2022] Open
Abstract
The sensation of bitter substances can alert an animal that a specific type of food is harmful and should not be consumed. However, not all bitter compounds are equally toxic and some may even be beneficial in certain contexts. Thus, taste systems in general may have a broader range of functions than just in alerting the animal. In this study we investigate bitter sensing and processing in Drosophila larvae using quinine, a substance perceived by humans as bitter. We show that behavioral choice, feeding, survival, and associative olfactory learning are all directly affected by quinine. On the cellular level, we show that 12 gustatory sensory receptor neurons that express both GR66a and GR33a are required for quinine-dependent choice and feeding behavior. Interestingly, these neurons are not necessary for quinine-dependent survival or associative learning. On the molecular receptor gene level, the GR33a receptor, but not GR66a, is required for quinine-dependent choice behavior. A screen for gustatory sensory receptor neurons that trigger quinine-dependent choice behavior revealed that a single GR97a receptor gene expressing neuron located in the peripheral terminal sense organ is partially necessary and sufficient. For the first time, we show that the elementary chemosensory system of the Drosophila larva can serve as a simple model to understand the neuronal basis of taste information processing on the single cell level with respect to different behavioral outputs.
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Affiliation(s)
| | - Lorena Mazija
- Department of Biology, University of Konstanz Konstanz, Germany
| | - Alexander Wüst
- Department of Biology, University of Konstanz Konstanz, Germany
| | - Andreas S Thum
- Department of Biology, University of Konstanz Konstanz, Germany
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50
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Rossi Stacconi MV, Hansson BS, Rybak J, Romani R. Comparative neuroanatomy of the antennal lobes of 2 homopteran species. Chem Senses 2014; 39:283-94. [PMID: 24443423 DOI: 10.1093/chemse/bjt114] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We compared the morphology of the primary olfactory center, the antennal lobe (AL), in 2 homopteran insects, Hyalesthes obsoletus Signoret (Homoptera: Cixiidae) and Scaphoideus titanus Ball (Homoptera: Cicadomorpha). The comparison between the ALs of the 2 species is particularly interesting considering that, although both use volatile cues to locate their host plants, their feeding behavior differs considerably: specifically, H. obsoletus is a highly polyphagous species, whereas S. titanus is strictly monophagous (on grapevine). Our investigation of the AL structure using immunocytochemical staining and antennal backfills did not reveal any sexual dimorphism in either the size of the ALs or in the size of individual glomeruli for either species. Instead, the AL of H. obsoletus displayed numerous and well-delineated glomeruli (about 130 in both sexes) arranged in a multilayered structure, whereas the smaller AL of S. titanus contained fewer than 15 glomerular-like structures. This difference is likely to reflect the comparatively reduced olfactory abilities in S. titanus, probably as a consequence of the reduced number of volatiles coming from the single host plant. Instead, in H. obsoletus, the ability to distinguish among several host plants may require a more complex olfactory neuronal network.
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