1
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Eckstein N, Bates AS, Champion A, Du M, Yin Y, Schlegel P, Lu AKY, Rymer T, Finley-May S, Paterson T, Parekh R, Dorkenwald S, Matsliah A, Yu SC, McKellar C, Sterling A, Eichler K, Costa M, Seung S, Murthy M, Hartenstein V, Jefferis GSXE, Funke J. Neurotransmitter classification from electron microscopy images at synaptic sites in Drosophila melanogaster. Cell 2024; 187:2574-2594.e23. [PMID: 38729112 PMCID: PMC11106717 DOI: 10.1016/j.cell.2024.03.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Revised: 10/04/2023] [Accepted: 03/13/2024] [Indexed: 05/12/2024]
Abstract
High-resolution electron microscopy of nervous systems has enabled the reconstruction of synaptic connectomes. However, we do not know the synaptic sign for each connection (i.e., whether a connection is excitatory or inhibitory), which is implied by the released transmitter. We demonstrate that artificial neural networks can predict transmitter types for presynapses from electron micrographs: a network trained to predict six transmitters (acetylcholine, glutamate, GABA, serotonin, dopamine, octopamine) achieves an accuracy of 87% for individual synapses, 94% for neurons, and 91% for known cell types across a D. melanogaster whole brain. We visualize the ultrastructural features used for prediction, discovering subtle but significant differences between transmitter phenotypes. We also analyze transmitter distributions across the brain and find that neurons that develop together largely express only one fast-acting transmitter (acetylcholine, glutamate, or GABA). We hope that our publicly available predictions act as an accelerant for neuroscientific hypothesis generation for the fly.
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Affiliation(s)
- Nils Eckstein
- HHMI Janelia Research Campus, Ashburn, VA, USA; Institute of Neuroinformatics UZH/ETHZ, Zurich, Switzerland
| | - Alexander Shakeel Bates
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, UK; Centre for Neural Circuits and Behaviour, The University of Oxford, Tinsley Building, Mansfield Road, Oxford OX1 3SR, UK; Department of Neurobiology and Howard Hughes Medical Institute, Harvard Medical School, Boston, MA, USA
| | - Andrew Champion
- Drosophila Connectomics Group, Department of Zoology, University of Cambridge, Cambridge, UK
| | - Michelle Du
- HHMI Janelia Research Campus, Ashburn, VA, USA
| | - Yijie Yin
- Drosophila Connectomics Group, Department of Zoology, University of Cambridge, Cambridge, UK
| | - Philipp Schlegel
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, UK; Drosophila Connectomics Group, Department of Zoology, University of Cambridge, Cambridge, UK
| | | | | | | | | | | | - Sven Dorkenwald
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ, USA
| | - Arie Matsliah
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ, USA
| | - Szi-Chieh Yu
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ, USA
| | - Claire McKellar
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ, USA
| | - Amy Sterling
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ, USA
| | - Katharina Eichler
- Drosophila Connectomics Group, Department of Zoology, University of Cambridge, Cambridge, UK
| | - Marta Costa
- Drosophila Connectomics Group, Department of Zoology, University of Cambridge, Cambridge, UK
| | - Sebastian Seung
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ, USA
| | - Mala Murthy
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ, USA
| | - Volker Hartenstein
- Department of Molecular Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, CA, USA
| | - Gregory S X E Jefferis
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, UK; Drosophila Connectomics Group, Department of Zoology, University of Cambridge, Cambridge, UK.
| | - Jan Funke
- HHMI Janelia Research Campus, Ashburn, VA, USA.
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2
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Mallick A, Tan HL, Epstein JM, Gaudry Q, Dacks AM. Serotonin acts through multiple cellular targets during an olfactory critical period. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.14.589413. [PMID: 38645269 PMCID: PMC11030346 DOI: 10.1101/2024.04.14.589413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
Serotonin (5-HT) is known to modulate early development during critical periods when experience drives heightened levels of plasticity in neurons. Here, we take advantage of the genetically tractable olfactory system of Drosophila to investigate how 5-HT modulates critical period plasticity in the CO2 sensing circuit of fruit flies. Our study reveals that 5HT modulation of multiple neuronal targets is necessary for experience-dependent structural changes in an odor processing circuit. The olfactory CPP is known to involve local inhibitory networks and consistent with this we found that knocking down 5-HT7 receptors in a subset of GABAergic local interneurons was sufficient to block CPP, as was knocking down GABA receptors expressed by olfactory sensory neurons (OSNs). Additionally, direct modulation of OSNs via 5-HT2B expression in the cognate OSNs sensing CO2 is also essential for CPP. Furthermore, 5-HT1B expression by serotonergic neurons in the olfactory system is also required during the critical period. Our study reveals that 5-HT modulation of multiple neuronal targets is necessary for experience-dependent structural changes in an odor processing circuit.
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Affiliation(s)
- Ahana Mallick
- Department of Biology, University of Maryland, College Park, MD 20742, USA
| | - Hua Leonhard Tan
- Department of Biology, University of Maryland, College Park, MD 20742, USA
| | | | - Quentin Gaudry
- Department of Biology, University of Maryland, College Park, MD 20742, USA
- Senior Author: These authors contributed equally
| | - Andrew M Dacks
- Departments of Biology and Neuroscience, West Virginia University, Morgantown, WV 26505, USA
- Senior Author: These authors contributed equally
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3
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Cheong HSJ, Boone KN, Bennett MM, Salman F, Ralston JD, Hatch K, Allen RF, Phelps AM, Cook AP, Phelps JS, Erginkaya M, Lee WCA, Card GM, Daly KC, Dacks AM. Organization of an ascending circuit that conveys flight motor state in Drosophila. Curr Biol 2024; 34:1059-1075.e5. [PMID: 38402616 PMCID: PMC10939832 DOI: 10.1016/j.cub.2024.01.071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 12/08/2023] [Accepted: 01/29/2024] [Indexed: 02/27/2024]
Abstract
Natural behaviors are a coordinated symphony of motor acts that drive reafferent (self-induced) sensory activation. Individual sensors cannot disambiguate exafferent (externally induced) from reafferent sources. Nevertheless, animals readily differentiate between these sources of sensory signals to carry out adaptive behaviors through corollary discharge circuits (CDCs), which provide predictive motor signals from motor pathways to sensory processing and other motor pathways. Yet, how CDCs comprehensively integrate into the nervous system remains unexplored. Here, we use connectomics, neuroanatomical, physiological, and behavioral approaches to resolve the network architecture of two pairs of ascending histaminergic neurons (AHNs) in Drosophila, which function as a predictive CDC in other insects. Both AHN pairs receive input primarily from a partially overlapping population of descending neurons, especially from DNg02, which controls wing motor output. Using Ca2+ imaging and behavioral recordings, we show that AHN activation is correlated to flight behavior and precedes wing motion. Optogenetic activation of DNg02 is sufficient to activate AHNs, indicating that AHNs are activated by descending commands in advance of behavior and not as a consequence of sensory input. Downstream, each AHN pair targets predominantly non-overlapping networks, including those that process visual, auditory, and mechanosensory information, as well as networks controlling wing, haltere, and leg sensorimotor control. These results support the conclusion that the AHNs provide a predictive motor signal about wing motor state to mostly non-overlapping sensory and motor networks. Future work will determine how AHN signaling is driven by other descending neurons and interpreted by AHN downstream targets to maintain adaptive sensorimotor performance.
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Affiliation(s)
- Han S J Cheong
- Department of Biology, West Virginia University, Morgantown, WV 26505, USA; Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA; Zuckerman Institute, Columbia University, New York, NY 10027, USA
| | - Kaitlyn N Boone
- Department of Biology, West Virginia University, Morgantown, WV 26505, USA; Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Marryn M Bennett
- Department of Biology, West Virginia University, Morgantown, WV 26505, USA
| | - Farzaan Salman
- Department of Biology, West Virginia University, Morgantown, WV 26505, USA
| | - Jacob D Ralston
- Department of Biology, West Virginia University, Morgantown, WV 26505, USA
| | - Kaleb Hatch
- Department of Biology, West Virginia University, Morgantown, WV 26505, USA
| | - Raven F Allen
- Department of Biology, West Virginia University, Morgantown, WV 26505, USA
| | - Alec M Phelps
- Department of Biology, West Virginia University, Morgantown, WV 26505, USA
| | - Andrew P Cook
- Department of Biology, West Virginia University, Morgantown, WV 26505, USA
| | - Jasper S Phelps
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA; Swiss Federal Institute of Technology Lausanne, 1015 Lausanne, Switzerland
| | - Mert Erginkaya
- Champalimaud Research, Champalimaud Centre for the Unknown, Lisbon 1400-038, Portugal
| | - Wei-Chung A Lee
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Gwyneth M Card
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA; Zuckerman Institute, Columbia University, New York, NY 10027, USA
| | - Kevin C Daly
- Department of Biology, West Virginia University, Morgantown, WV 26505, USA; Department of Neuroscience, West Virginia University, Morgantown, WV 26505, USA
| | - Andrew M Dacks
- Department of Biology, West Virginia University, Morgantown, WV 26505, USA; Department of Neuroscience, West Virginia University, Morgantown, WV 26505, USA.
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4
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Mallick A, Dacks AM, Gaudry Q. Olfactory Critical Periods: How Odor Exposure Shapes the Developing Brain in Mice and Flies. BIOLOGY 2024; 13:94. [PMID: 38392312 PMCID: PMC10886215 DOI: 10.3390/biology13020094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 01/26/2024] [Accepted: 01/30/2024] [Indexed: 02/24/2024]
Abstract
Neural networks have an extensive ability to change in response to environmental stimuli. This flexibility peaks during restricted windows of time early in life called critical periods. The ubiquitous occurrence of this form of plasticity across sensory modalities and phyla speaks to the importance of critical periods for proper neural development and function. Extensive investigation into visual critical periods has advanced our knowledge of the molecular events and key processes that underlie the impact of early-life experience on neuronal plasticity. However, despite the importance of olfaction for the overall survival of an organism, the cellular and molecular basis of olfactory critical periods have not garnered extensive study compared to visual critical periods. Recent work providing a comprehensive mapping of the highly organized olfactory neuropil and its development has in turn attracted a growing interest in how these circuits undergo plasticity during critical periods. Here, we perform a comparative review of olfactory critical periods in fruit flies and mice to provide novel insight into the importance of early odor exposure in shaping neural circuits and highlighting mechanisms found across sensory modalities.
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Affiliation(s)
- Ahana Mallick
- Department of Biology, University of Maryland, College Park, MD 20742, USA
| | - Andrew M Dacks
- Department of Biology, West Virginia University, Morgantown, WV 26505, USA
| | - Quentin Gaudry
- Department of Biology, University of Maryland, College Park, MD 20742, USA
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5
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Barth-Maron A, D'Alessandro I, Wilson RI. Interactions between specialized gain control mechanisms in olfactory processing. Curr Biol 2023; 33:5109-5120.e7. [PMID: 37967554 DOI: 10.1016/j.cub.2023.10.041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 08/16/2023] [Accepted: 10/23/2023] [Indexed: 11/17/2023]
Abstract
Gain control is a process that adjusts a system's sensitivity when input levels change. Neural systems contain multiple mechanisms of gain control, but we do not understand why so many mechanisms are needed or how they interact. Here, we investigate these questions in the Drosophila antennal lobe, where we identify several types of inhibitory interneurons with specialized gain control functions. We find that some interneurons are nonspiking, with compartmentalized calcium signals, and they specialize in intra-glomerular gain control. Conversely, we find that other interneurons are recruited by strong and widespread network input; they specialize in global presynaptic gain control. Using computational modeling and optogenetic perturbations, we show how these mechanisms can work together to improve stimulus discrimination while also minimizing temporal distortions in network activity. Our results demonstrate how the robustness of neural network function can be increased by interactions among diverse and specialized mechanisms of gain control.
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Affiliation(s)
- Asa Barth-Maron
- Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA
| | - Isabel D'Alessandro
- Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA
| | - Rachel I Wilson
- Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA.
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6
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Xiao N, Xu S, Li ZK, Tang M, Mao R, Yang T, Ma SX, Wang PH, Li MT, Sunilkumar A, Rouyer F, Cao LH, Luo DG. A single photoreceptor splits perception and entrainment by cotransmission. Nature 2023; 623:562-570. [PMID: 37880372 PMCID: PMC10651484 DOI: 10.1038/s41586-023-06681-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Accepted: 09/26/2023] [Indexed: 10/27/2023]
Abstract
Vision enables both image-forming perception, driven by a contrast-based pathway, and unconscious non-image-forming circadian photoentrainment, driven by an irradiance-based pathway1,2. Although two distinct photoreceptor populations are specialized for each visual task3-6, image-forming photoreceptors can additionally contribute to photoentrainment of the circadian clock in different species7-15. However, it is unknown how the image-forming photoreceptor pathway can functionally implement the segregation of irradiance signals required for circadian photoentrainment from contrast signals required for image perception. Here we report that the Drosophila R8 photoreceptor separates image-forming and irradiance signals by co-transmitting two neurotransmitters, histamine and acetylcholine. This segregation is further established postsynaptically by histamine-receptor-expressing unicolumnar retinotopic neurons and acetylcholine-receptor-expressing multicolumnar integration neurons. The acetylcholine transmission from R8 photoreceptors is sustained by an autocrine negative feedback of the cotransmitted histamine during the light phase of light-dark cycles. At the behavioural level, elimination of histamine and acetylcholine transmission impairs R8-driven motion detection and circadian photoentrainment, respectively. Thus, a single type of photoreceptor can achieve the dichotomy of visual perception and circadian photoentrainment as early as the first visual synapses, revealing a simple yet robust mechanism to segregate and translate distinct sensory features into different animal behaviours.
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Affiliation(s)
- Na Xiao
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing, China
- IDG/McGovern Institute for Brain Research, Peking University, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
- School of Life Sciences, Peking University, Beijing, China
- Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Shuang Xu
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing, China
- IDG/McGovern Institute for Brain Research, Peking University, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
- School of Life Sciences, Peking University, Beijing, China
| | - Ze-Kai Li
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing, China
- IDG/McGovern Institute for Brain Research, Peking University, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
- School of Life Sciences, Peking University, Beijing, China
| | - Min Tang
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing, China
- IDG/McGovern Institute for Brain Research, Peking University, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
- School of Life Sciences, Peking University, Beijing, China
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Renbo Mao
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing, China
- IDG/McGovern Institute for Brain Research, Peking University, Beijing, China
| | - Tian Yang
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing, China
- IDG/McGovern Institute for Brain Research, Peking University, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
- School of Life Sciences, Peking University, Beijing, China
| | - Si-Xing Ma
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing, China
- IDG/McGovern Institute for Brain Research, Peking University, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
- School of Life Sciences, Peking University, Beijing, China
| | - Peng-Hao Wang
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing, China
- IDG/McGovern Institute for Brain Research, Peking University, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
- School of Life Sciences, Peking University, Beijing, China
| | - Meng-Tong Li
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing, China
- IDG/McGovern Institute for Brain Research, Peking University, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
- School of Life Sciences, Peking University, Beijing, China
- Zuckerman Mind Brain and Behavior Institute, Columbia University, New York, NY, USA
| | - Ajay Sunilkumar
- Institut des Neurosciences Paris-Saclay, Université Paris-Sud, Université Paris-Saclay, CNRS, Gif-sur-Yvette, France
| | - François Rouyer
- Institut des Neurosciences Paris-Saclay, Université Paris-Sud, Université Paris-Saclay, CNRS, Gif-sur-Yvette, France
| | - Li-Hui Cao
- School of Basic Medical Sciences, Beijing Key Laboratory of Neural Regeneration and Repair, Capital Medical University, Beijing, China
| | - Dong-Gen Luo
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing, China.
- IDG/McGovern Institute for Brain Research, Peking University, Beijing, China.
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China.
- School of Life Sciences, Peking University, Beijing, China.
- Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China.
- Chinese Institute for Brain Research, Beijing, China.
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7
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Sizemore TR, Jonaitis J, Dacks AM. Heterogeneous receptor expression underlies non-uniform peptidergic modulation of olfaction in Drosophila. Nat Commun 2023; 14:5280. [PMID: 37644052 PMCID: PMC10465596 DOI: 10.1038/s41467-023-41012-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 08/21/2023] [Indexed: 08/31/2023] Open
Abstract
Sensory systems are dynamically adjusted according to the animal's ongoing needs by neuromodulators, such as neuropeptides. Neuropeptides are often widely-distributed throughout sensory networks, but it is unclear whether such neuropeptides uniformly modulate network activity. Here, we leverage the Drosophila antennal lobe (AL) to resolve whether myoinhibitory peptide (MIP) uniformly modulates AL processing. Despite being uniformly distributed across the AL, MIP decreases olfactory input to some glomeruli, while increasing olfactory input to other glomeruli. We reveal that a heterogeneous ensemble of local interneurons (LNs) are the sole source of AL MIP, and show that differential expression of the inhibitory MIP receptor across glomeruli allows MIP to act on distinct intraglomerular substrates. Our findings demonstrate how even a seemingly simple case of modulation can have complex consequences on network processing by acting non-uniformly within different components of the overall network.
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Affiliation(s)
- Tyler R Sizemore
- Department of Biology, Life Sciences Building, West Virginia University, Morgantown, WV, 26506, USA.
- Department of Molecular, Cellular, and Developmental Biology, Yale Science Building, Yale University, New Haven, CT, 06520-8103, USA.
| | - Julius Jonaitis
- Department of Biology, Life Sciences Building, West Virginia University, Morgantown, WV, 26506, USA
| | - Andrew M Dacks
- Department of Biology, Life Sciences Building, West Virginia University, Morgantown, WV, 26506, USA.
- Department of Neuroscience, West Virginia University, Morgantown, WV, 26506, USA.
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8
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Marachlian E, Huerta R, Locatelli FF. Gain modulation and odor concentration invariance in early olfactory networks. PLoS Comput Biol 2023; 19:e1011176. [PMID: 37343029 DOI: 10.1371/journal.pcbi.1011176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 05/11/2023] [Indexed: 06/23/2023] Open
Abstract
The broad receptive field of the olfactory receptors constitutes the basis of a combinatorial code that allows animals to detect and discriminate many more odorants than the actual number of receptor types that they express. One drawback is that high odor concentrations recruit lower affinity receptors which can lead to the perception of qualitatively different odors. Here we addressed the contribution that signal-processing in the antennal lobe makes to reduce concentration dependence in odor representation. By means of calcium imaging and pharmacological approach we describe the contribution that GABA receptors play in terms of the amplitude and temporal profiles of the signals that convey odor information from the antennal lobes to higher brain centers. We found that GABA reduces the amplitude of odor elicited signals and the number of glomeruli that are recruited in an odor-concentration-dependent manner. Blocking GABA receptors decreases the correlation among glomerular activity patterns elicited by different concentrations of the same odor. In addition, we built a realistic mathematical model of the antennal lobe that was used to test the viability of the proposed mechanisms and to evaluate the processing properties of the AL network under conditions that cannot be achieved in physiology experiments. Interestingly, even though based on a rather simple topology and cell interactions solely mediated by GABAergic lateral inhibitions, the AL model reproduced key features of the AL response upon different odor concentrations and provides plausible solutions for concentration invariant recognition of odors by artificial sensors.
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Affiliation(s)
- Emiliano Marachlian
- Instituto de Fisiología Biología Molecular y Neurociencias (IFIByNE-UBA-CONICET) and Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Ramón Huerta
- BioCircuits Institute, University of California San Diego, La Jolla, California, United States of America
| | - Fernando F Locatelli
- Instituto de Fisiología Biología Molecular y Neurociencias (IFIByNE-UBA-CONICET) and Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
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9
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Cheong HSJ, Boone KN, Bennett MM, Salman F, Ralston JD, Hatch K, Allen RF, Phelps AM, Cook AP, Phelps JS, Erginkaya M, Lee WCA, Card GM, Daly KC, Dacks AM. Organization of an Ascending Circuit that Conveys Flight Motor State. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.07.544074. [PMID: 37333334 PMCID: PMC10274802 DOI: 10.1101/2023.06.07.544074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Natural behaviors are a coordinated symphony of motor acts which drive self-induced or reafferent sensory activation. Single sensors only signal presence and magnitude of a sensory cue; they cannot disambiguate exafferent (externally-induced) from reafferent sources. Nevertheless, animals readily differentiate between these sources of sensory signals to make appropriate decisions and initiate adaptive behavioral outcomes. This is mediated by predictive motor signaling mechanisms, which emanate from motor control pathways to sensory processing pathways, but how predictive motor signaling circuits function at the cellular and synaptic level is poorly understood. We use a variety of techniques, including connectomics from both male and female electron microscopy volumes, transcriptomics, neuroanatomical, physiological and behavioral approaches to resolve the network architecture of two pairs of ascending histaminergic neurons (AHNs), which putatively provide predictive motor signals to several sensory and motor neuropil. Both AHN pairs receive input primarily from an overlapping population of descending neurons, many of which drive wing motor output. The two AHN pairs target almost exclusively non-overlapping downstream neural networks including those that process visual, auditory and mechanosensory information as well as networks coordinating wing, haltere, and leg motor output. These results support the conclusion that the AHN pairs multi-task, integrating a large amount of common input, then tile their output in the brain, providing predictive motor signals to non-overlapping sensory networks affecting motor control both directly and indirectly.
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Affiliation(s)
- Han S. J. Cheong
- Department of Biology, West Virginia University, Morgantown, WV 26505, United States of America
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, United States of America
| | - Kaitlyn N. Boone
- Department of Biology, West Virginia University, Morgantown, WV 26505, United States of America
| | - Marryn M. Bennett
- Department of Biology, West Virginia University, Morgantown, WV 26505, United States of America
| | - Farzaan Salman
- Department of Biology, West Virginia University, Morgantown, WV 26505, United States of America
| | - Jacob D. Ralston
- Department of Biology, West Virginia University, Morgantown, WV 26505, United States of America
| | - Kaleb Hatch
- Department of Biology, West Virginia University, Morgantown, WV 26505, United States of America
| | - Raven F. Allen
- Department of Biology, West Virginia University, Morgantown, WV 26505, United States of America
| | - Alec M. Phelps
- Department of Biology, West Virginia University, Morgantown, WV 26505, United States of America
| | - Andrew P. Cook
- Department of Biology, West Virginia University, Morgantown, WV 26505, United States of America
| | - Jasper S. Phelps
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, United States of America
| | - Mert Erginkaya
- Champalimaud Research, Champalimaud Centre for the Unknown, Lisbon, 1400-038, Portugal
| | - Wei-Chung A. Lee
- F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, United States of America
| | - Gwyneth M. Card
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, United States of America
- Zuckerman Institute, Columbia University, New York, NY 10027, United States of America
| | - Kevin C. Daly
- Department of Biology, West Virginia University, Morgantown, WV 26505, United States of America
- Department of Neuroscience, West Virginia University, Morgantown, WV 26505, United States of America
| | - Andrew M. Dacks
- Department of Biology, West Virginia University, Morgantown, WV 26505, United States of America
- Department of Neuroscience, West Virginia University, Morgantown, WV 26505, United States of America
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10
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Paoli M, Antonacci Y, Albi A, Faes L, Haase A. Granger Causality Analysis of Transient Calcium Dynamics in the Honey Bee Antennal Lobe Network. INSECTS 2023; 14:539. [PMID: 37367355 DOI: 10.3390/insects14060539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 05/28/2023] [Accepted: 06/08/2023] [Indexed: 06/28/2023]
Abstract
Odorant processing presents multiple parallels across animal species, and insects became relevant models for the study of olfactory coding because of the tractability of the underlying neural circuits. Within the insect brain, odorants are received by olfactory sensory neurons and processed by the antennal lobe network. Such a network comprises multiple nodes, named glomeruli, that receive sensory information and are interconnected by local interneurons participating in shaping the neural representation of an odorant. The study of functional connectivity between the nodes of a sensory network in vivo is a challenging task that requires simultaneous recording from multiple nodes at high temporal resolutions. Here, we followed the calcium dynamics of antennal lobe glomeruli and applied Granger causality analysis to assess the functional connectivity among network nodes in the presence and absence of an odorous stimulus. This approach revealed the existence of causal connectivity links between antennal lobe glomeruli in the absence of olfactory stimulation, while at odor arrival, the connectivity network's density increased and became stimulus-specific. Thus, such an analytical approach may provide a new tool for the investigation of neural network plasticity in vivo.
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Affiliation(s)
- Marco Paoli
- Research Center of Animal Cognition, Center for Integrative Biology, CNRS, University of Toulouse, 31400 Toulouse, France
| | - Yuri Antonacci
- Dipartimento di Ingegneria, Università di Palermo, 90128 Palermo, Italy
| | - Angela Albi
- Department of Collective Behavior, Max Planck Institute of Animal Behavior, 78457 Konstanz, Germany
- Department of Biology, University of Konstanz, 78457 Konstanz, Germany
| | - Luca Faes
- Dipartimento di Ingegneria, Università di Palermo, 90128 Palermo, Italy
| | - Albrecht Haase
- Center for Mind/Brain Science (CIMeC), University of Trento, 38068 Rovereto, Italy
- Department of Physics, University of Trento, 38123 Povo, Italy
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11
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Gugel ZV, Maurais EG, Hong EJ. Chronic exposure to odors at naturally occurring concentrations triggers limited plasticity in early stages of Drosophila olfactory processing. eLife 2023; 12:e85443. [PMID: 37195027 PMCID: PMC10229125 DOI: 10.7554/elife.85443] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Accepted: 02/06/2023] [Indexed: 05/18/2023] Open
Abstract
In insects and mammals, olfactory experience in early life alters olfactory behavior and function in later life. In the vinegar fly Drosophila, flies chronically exposed to a high concentration of a monomolecular odor exhibit reduced behavioral aversion to the familiar odor when it is reencountered. This change in olfactory behavior has been attributed to selective decreases in the sensitivity of second-order olfactory projection neurons (PNs) in the antennal lobe that respond to the overrepresented odor. However, since odorant compounds do not occur at similarly high concentrations in natural sources, the role of odor experience-dependent plasticity in natural environments is unclear. Here, we investigated olfactory plasticity in the antennal lobe of flies chronically exposed to odors at concentrations that are typically encountered in natural odor sources. These stimuli were chosen to each strongly and selectively excite a single class of primary olfactory receptor neuron (ORN), thus facilitating a rigorous assessment of the selectivity of olfactory plasticity for PNs directly excited by overrepresented stimuli. Unexpectedly, we found that chronic exposure to three such odors did not result in decreased PN sensitivity but rather mildly increased responses to weak stimuli in most PN types. Odor-evoked PN activity in response to stronger stimuli was mostly unaffected by odor experience. When present, plasticity was observed broadly in multiple PN types and thus was not selective for PNs receiving direct input from the chronically active ORNs. We further investigated the DL5 olfactory coding channel and found that chronic odor-mediated excitation of its input ORNs did not affect PN intrinsic properties, local inhibitory innervation, ORN responses or ORN-PN synaptic strength; however, broad-acting lateral excitation evoked by some odors was increased. These results show that PN odor coding is only mildly affected by strong persistent activation of a single olfactory input, highlighting the stability of early stages of insect olfactory processing to significant perturbations in the sensory environment.
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Affiliation(s)
- Zhannetta V Gugel
- Division of Biology and Biological Engineering, California Institute of TechnologyPasadenaUnited States
| | - Elizabeth G Maurais
- Division of Biology and Biological Engineering, California Institute of TechnologyPasadenaUnited States
| | - Elizabeth J Hong
- Division of Biology and Biological Engineering, California Institute of TechnologyPasadenaUnited States
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12
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Parisi MJ, Aimino MA, Mosca TJ. A conditional strategy for cell-type-specific labeling of endogenous excitatory synapses in Drosophila. CELL REPORTS METHODS 2023; 3:100477. [PMID: 37323572 PMCID: PMC10261928 DOI: 10.1016/j.crmeth.2023.100477] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 02/28/2023] [Accepted: 04/19/2023] [Indexed: 06/17/2023]
Abstract
Chemical neurotransmission occurs at specialized contacts where neurotransmitter release machinery apposes neurotransmitter receptors to underlie circuit function. A series of complex events underlies pre- and postsynaptic protein recruitment to neuronal connections. To better study synaptic development in individual neurons, we need cell-type-specific strategies to visualize endogenous synaptic proteins. Although presynaptic strategies exist, postsynaptic proteins remain less studied because of a paucity of cell-type-specific reagents. To study excitatory postsynapses with cell-type specificity, we engineered dlg1[4K], a conditionally labeled marker of Drosophila excitatory postsynaptic densities. With binary expression systems, dlg1[4K] labels central and peripheral postsynapses in larvae and adults. Using dlg1[4K], we find that distinct rules govern postsynaptic organization in adult neurons, multiple binary expression systems can concurrently label pre- and postsynapse in a cell-type-specific manner, and neuronal DLG1 can sometimes localize presynaptically. These results validate our strategy for conditional postsynaptic labeling and demonstrate principles of synaptic organization.
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Affiliation(s)
- Michael J. Parisi
- Department of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Bluemle Life Sciences Building, Philadelphia, PA 19107, USA
| | - Michael A. Aimino
- Department of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Bluemle Life Sciences Building, Philadelphia, PA 19107, USA
| | - Timothy J. Mosca
- Department of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Bluemle Life Sciences Building, Philadelphia, PA 19107, USA
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13
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Lazar AA, Liu T, Yeh CH. The functional logic of odor information processing in the Drosophila antennal lobe. PLoS Comput Biol 2023; 19:e1011043. [PMID: 37083547 PMCID: PMC10156017 DOI: 10.1371/journal.pcbi.1011043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 05/03/2023] [Accepted: 03/22/2023] [Indexed: 04/22/2023] Open
Abstract
Recent advances in molecular transduction of odorants in the Olfactory Sensory Neurons (OSNs) of the Drosophila Antenna have shown that the odorant object identity is multiplicatively coupled with the odorant concentration waveform. The resulting combinatorial neural code is a confounding representation of odorant semantic information (identity) and syntactic information (concentration). To distill the functional logic of odor information processing in the Antennal Lobe (AL) a number of challenges need to be addressed including 1) how is the odorant semantic information decoupled from the syntactic information at the level of the AL, 2) how are these two information streams processed by the diverse AL Local Neurons (LNs) and 3) what is the end-to-end functional logic of the AL? By analyzing single-channel physiology recordings at the output of the AL, we found that the Projection Neuron responses can be decomposed into a concentration-invariant component, and two transient components boosting the positive/negative concentration contrast that indicate onset/offset timing information of the odorant object. We hypothesized that the concentration-invariant component, in the multi-channel context, is the recovered odorant identity vector presented between onset/offset timing events. We developed a model of LN pathways in the Antennal Lobe termed the differential Divisive Normalization Processors (DNPs), which robustly extract the semantics (the identity of the odorant object) and the ON/OFF semantic timing events indicating the presence/absence of an odorant object. For real-time processing with spiking PN models, we showed that the phase-space of the biological spike generator of the PN offers an intuit perspective for the representation of recovered odorant semantics and examined the dynamics induced by the odorant semantic timing events. Finally, we provided theoretical and computational evidence for the functional logic of the AL as a robust ON-OFF odorant object identity recovery processor across odorant identities, concentration amplitudes and waveform profiles.
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Affiliation(s)
- Aurel A Lazar
- Department of Electrical Engineering, Columbia University, New York, NY, United States of America
| | - Tingkai Liu
- Department of Electrical Engineering, Columbia University, New York, NY, United States of America
| | - Chung-Heng Yeh
- Department of Electrical Engineering, Columbia University, New York, NY, United States of America
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14
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Fabian B, Sachse S. Experience-dependent plasticity in the olfactory system of Drosophila melanogaster and other insects. Front Cell Neurosci 2023; 17:1130091. [PMID: 36923450 PMCID: PMC10010147 DOI: 10.3389/fncel.2023.1130091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 02/07/2023] [Indexed: 02/24/2023] Open
Abstract
It is long known that the nervous system of vertebrates can be shaped by internal and external factors. On the other hand, the nervous system of insects was long assumed to be stereotypic, although evidence for plasticity effects accumulated for several decades. To cover the topic comprehensively, this review recapitulates the establishment of the term "plasticity" in neuroscience and introduces its original meaning. We describe the basic composition of the insect olfactory system using Drosophila melanogaster as a representative example and outline experience-dependent plasticity effects observed in this part of the brain in a variety of insects, including hymenopterans, lepidopterans, locusts, and flies. In particular, we highlight recent advances in the study of experience-dependent plasticity effects in the olfactory system of D. melanogaster, as it is the most accessible olfactory system of all insect species due to the genetic tools available. The partly contradictory results demonstrate that morphological, physiological and behavioral changes in response to long-term olfactory stimulation are more complex than previously thought. Different molecular mechanisms leading to these changes were unveiled in the past and are likely responsible for this complexity. We discuss common problems in the study of experience-dependent plasticity, ways to overcome them, and future directions in this area of research. In addition, we critically examine the transferability of laboratory data to natural systems to address the topic as holistically as possible. As a mechanism that allows organisms to adapt to new environmental conditions, experience-dependent plasticity contributes to an animal's resilience and is therefore a crucial topic for future research, especially in an era of rapid environmental changes.
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Affiliation(s)
| | - Silke Sachse
- Research Group Olfactory Coding, Max Planck Institute for Chemical Ecology, Jena, Germany
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15
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Synaptic Development in Diverse Olfactory Neuron Classes Uses Distinct Temporal and Activity-Related Programs. J Neurosci 2023; 43:28-55. [PMID: 36446587 PMCID: PMC9838713 DOI: 10.1523/jneurosci.0884-22.2022] [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: 05/12/2022] [Revised: 10/18/2022] [Accepted: 11/02/2022] [Indexed: 12/03/2022] Open
Abstract
Developing neurons must meet core molecular, cellular, and temporal requirements to ensure the correct formation of synapses, resulting in functional circuits. However, because of the vast diversity in neuronal class and function, it is unclear whether or not all neurons use the same organizational mechanisms to form synaptic connections and achieve functional and morphologic maturation. Moreover, it remains unknown whether neurons united in a common goal and comprising the same sensory circuit develop on similar timescales and use identical molecular approaches to ensure the formation of the correct number of synapses. To begin to answer these questions, we took advantage of the Drosophila antennal lobe (AL), a model olfactory circuit with remarkable genetic access and synapse-level resolution. Using tissue-specific genetic labeling of active zones, we performed a quantitative analysis of synapse formation in multiple classes of neurons of both sexes throughout development and adulthood. We found that olfactory receptor neurons (ORNs), projection neurons (PNs), and local interneurons (LNs) each have unique time courses of synaptic development, addition, and refinement, demonstrating that each class follows a distinct developmental program. This raised the possibility that these classes may also have distinct molecular requirements for synapse formation. We genetically altered neuronal activity in each neuronal subtype and observed differing effects on synapse number based on the neuronal class examined. Silencing neuronal activity in ORNs, PNs, and LNs impaired synaptic development but only in ORNs did enhancing neuronal activity influence synapse formation. ORNs and LNs demonstrated similar impairment of synaptic development with enhanced activity of a master kinase, GSK-3β, suggesting that neuronal activity and GSK-3β kinase activity function in a common pathway. ORNs also, however, demonstrated impaired synaptic development with GSK-3β loss-of-function, suggesting additional activity-independent roles in development. Ultimately, our results suggest that the requirements for synaptic development are not uniform across all neuronal classes with considerable diversity existing in both their developmental time frames and molecular requirements. These findings provide novel insights into the mechanisms of synaptic development and lay the foundation for future work determining their underlying etiologies.SIGNIFICANCE STATEMENT Distinct olfactory neuron classes in Drosophila develop a mature synaptic complement over unique timelines and using distinct activity-dependent and molecular programs, despite having the same generalized goal of olfactory sensation.
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16
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Zhao Y, Duan J, Han Z, Engström Y, Hartenstein V. Identification of a GABAergic neuroblast lineage modulating sweet and bitter taste sensitivity. Curr Biol 2022; 32:5354-5363.e3. [PMID: 36347251 PMCID: PMC10728805 DOI: 10.1016/j.cub.2022.10.029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 06/16/2022] [Accepted: 10/14/2022] [Indexed: 11/09/2022]
Abstract
In Drosophila melanogaster, processing of gustatory information and controlling feeding behavior are executed by neural circuits located in the subesophageal zone (SEZ) of the brain.1 Gustatory receptor neurons (GRNs) project their axons in the primary gustatory center (PGC), which is located in the SEZ.1,2,3,4 To address the function of the PGC, we need detailed information about the different classes of gustatory interneurons that frame the PGC. In this work, we screened large collections of driver lines for SEZ interneuron-specific labeling and subsequently used candidate lines to access the SEZ neuroblast lineages. We converted 130 Gal4 lines to LexA drivers and carried out functional screening using calcium imaging. We found one neuroblast lineage, TRdm, whose neurons responded to both sweet and bitter tastants, and formed green fluorescent protein (GFP) reconstitution across synaptic partners (GRASP)-positive synapses with sweet sensory neurons. TRdm neurons express the inhibitory transmitter GABA, and silencing these neurons increases appetitive feeding behavior. These results demonstrate that TRdm generates a class of inhibitory local neurons that control taste sensitivity in Drosophila.
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Affiliation(s)
- Yunpo Zhao
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden; Biozentrum, University of Basel, 4056 Basel, Switzerland; Center for Precision Disease Modeling, University of Maryland School of Medicine, Baltimore 21201, USA.
| | - Jianli Duan
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden; Center for Precision Disease Modeling, University of Maryland School of Medicine, Baltimore 21201, USA
| | - Zhe Han
- Center for Precision Disease Modeling, University of Maryland School of Medicine, Baltimore 21201, USA
| | - Ylva Engström
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden
| | - Volker Hartenstein
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles 90095-1606, USA.
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17
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Calvin-Cejudo L, Martin F, Mendez LR, Coya R, Castañeda-Sampedro A, Gomez-Diaz C, Alcorta E. Neuron-glia interaction at the receptor level affects olfactory perception in adult Drosophila. iScience 2022; 26:105837. [PMID: 36624835 PMCID: PMC9823236 DOI: 10.1016/j.isci.2022.105837] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 11/17/2022] [Accepted: 12/16/2022] [Indexed: 12/23/2022] Open
Abstract
Some types of glia play an active role in neuronal signaling by modifying their activity although little is known about their role in sensory information signaling at the receptor level. In this research, we report a functional role for the glia that surround the soma of the olfactory receptor neurons (OSNs) in adult Drosophila. Specific genetic modifications have been targeted to this cell type to obtain live individuals who are tested for olfactory preference and display changes both increasing and reducing sensitivity. A closer look at the antenna by Ca2+ imaging shows that odor activates the OSNs, which subsequently produce an opposite and smaller effect in the glia that partially counterbalances neuronal activation. Therefore, these glia may play a dual role in preventing excessive activation of the OSNs at high odorant concentrations and tuning the chemosensory window for the individual according to the network structure in the receptor organ.
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Affiliation(s)
- Laura Calvin-Cejudo
- Group of Neurobiology of the Sensory Systems (NEUROSEN), Department of Functional Biology, Faculty of Medicine, University of Oviedo, 33006 Oviedo, Spain
| | - Fernando Martin
- Group of Neurobiology of the Sensory Systems (NEUROSEN), Department of Functional Biology, Faculty of Medicine, University of Oviedo, 33006 Oviedo, Spain
| | - Luis R. Mendez
- Group of Neurobiology of the Sensory Systems (NEUROSEN), Department of Functional Biology, Faculty of Medicine, University of Oviedo, 33006 Oviedo, Spain
| | - Ruth Coya
- Group of Neurobiology of the Sensory Systems (NEUROSEN), Department of Functional Biology, Faculty of Medicine, University of Oviedo, 33006 Oviedo, Spain
| | - Ana Castañeda-Sampedro
- Group of Neurobiology of the Sensory Systems (NEUROSEN), Department of Functional Biology, Faculty of Medicine, University of Oviedo, 33006 Oviedo, Spain
| | - Carolina Gomez-Diaz
- Group of Neurobiology of the Sensory Systems (NEUROSEN), Department of Functional Biology, Faculty of Medicine, University of Oviedo, 33006 Oviedo, Spain
| | - Esther Alcorta
- Group of Neurobiology of the Sensory Systems (NEUROSEN), Department of Functional Biology, Faculty of Medicine, University of Oviedo, 33006 Oviedo, Spain
- Corresponding author
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18
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Qiu S, Sun K, Di Z. Long-range connections are crucial for synchronization transition in a computational model of Drosophila brain dynamics. Sci Rep 2022; 12:20104. [PMID: 36418353 PMCID: PMC9684149 DOI: 10.1038/s41598-022-17544-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 07/27/2022] [Indexed: 11/24/2022] Open
Abstract
The synchronization transition type has been the focus of attention in recent years because it is associated with many functional characteristics of the brain. In this paper, the synchronization transition in neural networks with sleep-related biological drives in Drosophila is investigated. An electrical synaptic neural network is established to research the difference between the synchronization transition of the network during sleep and wake, in which neurons regularly spike during sleep and chaotically spike during wake. The synchronization transition curves are calculated mainly using the global instantaneous order parameters S. The underlying mechanisms and types of synchronization transition during sleep are different from those during wake. During sleep, regardless of the network structure, a frustrated (discontinuous) transition can be observed. Moreover, the phenomenon of quasi periodic partial synchronization is observed in ring-shaped regular network with and without random long-range connections. As the network becomes dense, the synchronization of the network only needs to slightly increase the coupling strength g. While during wake, the synchronization transition of the neural network is very dependent on the network structure, and three mechanisms of synchronization transition have emerged: discontinuous synchronization (explosive synchronization and frustrated synchronization), and continuous synchronization. The random long-range connections is the main topological factor that plays an important role in the resulting synchronization transition. Furthermore, similarities and differences are found by comparing synchronization transition research for the Hodgkin-Huxley neural network in the beta-band and gammma-band, which can further improve the synchronization phase transition research of biologically motivated neural networks. A complete research framework can also be used to study coupled nervous systems, which can be extended to general coupled dynamic systems.
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Affiliation(s)
- Shuihan Qiu
- grid.20513.350000 0004 1789 9964International Academic Center of Complex Systems, Beijing Normal University, Zhuhai, 519087 China ,grid.20513.350000 0004 1789 9964School of Systems Science, Beijing Normal University, Beijing, 100875 China
| | - Kaijia Sun
- grid.20513.350000 0004 1789 9964School of Systems Science, Beijing Normal University, Beijing, 100875 China
| | - Zengru Di
- grid.20513.350000 0004 1789 9964International Academic Center of Complex Systems, Beijing Normal University, Zhuhai, 519087 China ,grid.20513.350000 0004 1789 9964School of Systems Science, Beijing Normal University, Beijing, 100875 China
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19
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Zocchi D, Ye ES, Hauser V, O'Connell TF, Hong EJ. Parallel encoding of CO 2 in attractive and aversive glomeruli by selective lateral signaling between olfactory afferents. Curr Biol 2022; 32:4225-4239.e7. [PMID: 36070776 PMCID: PMC9561050 DOI: 10.1016/j.cub.2022.08.025] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 07/13/2022] [Accepted: 08/10/2022] [Indexed: 12/14/2022]
Abstract
We describe a novel form of selective crosstalk between specific classes of primary olfactory receptor neurons (ORNs) in the Drosophila antennal lobe. Neurotransmitter release from ORNs is driven by two distinct sources of excitation: direct activity derived from the odorant receptor and stimulus-selective lateral signals originating from stereotypic subsets of other ORNs. Consequently, the level of presynaptic neurotransmitter release from an ORN can be significantly dissociated from its firing rate. Stimulus-selective lateral signaling results in the distributed representation of CO2-a behaviorally important environmental cue that directly excites a single ORN class-in multiple olfactory glomeruli, each with distinct response dynamics. CO2-sensitive glomeruli coupled to behavioral attraction respond preferentially to fast changes in CO2 concentration, whereas those coupled to behavioral aversion more closely follow absolute levels of CO2. Behavioral responses to CO2 also depend on the temporal structure of the stimulus: flies walk upwind to fluctuating, but not sustained, pulses of CO2. Stimulus-selective lateral signaling generalizes to additional odors and glomeruli, revealing a subnetwork of lateral interactions between ORNs that reshapes the spatial and temporal structure of odor representations in a stimulus-specific manner.
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Affiliation(s)
- Dhruv Zocchi
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA; Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Emily S Ye
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Virginie Hauser
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Thomas F O'Connell
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Elizabeth J Hong
- Division of Biology & Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
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20
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Hildebrandt K, Klöppel C, Gogel J, Hartenstein V, Walldorf U. Orthopedia expression during Drosophila melanogaster nervous system development and its regulation by microRNA-252. Dev Biol 2022; 492:87-100. [PMID: 36179878 DOI: 10.1016/j.ydbio.2022.09.006] [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: 07/15/2022] [Revised: 09/05/2022] [Accepted: 09/19/2022] [Indexed: 11/03/2022]
Abstract
During brain development of Drosophila melanogaster many transcription factors are involved in regulating neural fate and morphogenesis. In our study we show that the transcription factor Orthopedia (Otp), a member of the 57B homeobox gene cluster, plays an important role in this process. Otp is expressed in a stable pattern in defined lineages from mid-embryonic stages into the adult brain and therefore a very stable marker for these lineages. We determined the abundance of the two different otp transcripts in the brain and hindgut during development using qPCR. CRISPR/Cas9 generated otp mutants of the longer protein form significantly affect the expression of Otp in specific areas. We generated an otp enhancer trap strain by gene targeting and reintegration of Gal4, which mimics the complete expression of otp during development except the embryonic hindgut expression. Since in the embryo, the expression of Otp is posttranscriptionally regulated, we looked for putative miRNAs interacting with the otp 3'UTR, and identified microRNA-252 as a candidate. Further analyses with mutated and deleted forms of the microRNA-252 interacting sequence in the otp 3'UTR demonstrate an in vivo interaction of microRNA-252 with the otp 3'UTR. An effect of this interaction is seen in the adult brain, where Otp expression is partially abolished in a knockout strain of microRNA-252. Our results show that Otp is another important factor for brain development in Drosophila melanogaster.
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Affiliation(s)
- Kirsten Hildebrandt
- Developmental Biology, Saarland University, Building 61, 66421, Homburg, Saar, Germany
| | - Christine Klöppel
- Developmental Biology, Saarland University, Building 61, 66421, Homburg, Saar, Germany
| | - Jasmin Gogel
- Developmental Biology, Saarland University, Building 61, 66421, Homburg, Saar, Germany
| | - Volker Hartenstein
- Department of Molecular Cell and Developmental Biology, University of California, Los Angeles, CA, 90095, USA
| | - Uwe Walldorf
- Developmental Biology, Saarland University, Building 61, 66421, Homburg, Saar, Germany.
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21
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Vaughn MJ, Haas JS. On the Diverse Functions of Electrical Synapses. Front Cell Neurosci 2022; 16:910015. [PMID: 35755782 PMCID: PMC9219736 DOI: 10.3389/fncel.2022.910015] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 05/25/2022] [Indexed: 11/13/2022] Open
Abstract
Electrical synapses are the neurophysiological product of gap junctional pores between neurons that allow bidirectional flow of current between neurons. They are expressed throughout the mammalian nervous system, including cortex, hippocampus, thalamus, retina, cerebellum, and inferior olive. Classically, the function of electrical synapses has been associated with synchrony, logically following that continuous conductance provided by gap junctions facilitates the reduction of voltage differences between coupled neurons. Indeed, electrical synapses promote synchrony at many anatomical and frequency ranges across the brain. However, a growing body of literature shows there is greater complexity to the computational function of electrical synapses. The paired membranes that embed electrical synapses act as low-pass filters, and as such, electrical synapses can preferentially transfer spike after hyperpolarizations, effectively providing spike-dependent inhibition. Other functions include driving asynchronous firing, improving signal to noise ratio, aiding in discrimination of dissimilar inputs, or dampening signals by shunting current. The diverse ways by which electrical synapses contribute to neuronal integration merits furthers study. Here we review how functions of electrical synapses vary across circuits and brain regions and depend critically on the context of the neurons and brain circuits involved. Computational modeling of electrical synapses embedded in multi-cellular models and experiments utilizing optical control and measurement of cellular activity will be essential in determining the specific roles performed by electrical synapses in varying contexts.
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Affiliation(s)
- Mitchell J Vaughn
- Department of Biological Sciences, Lehigh University, Bethlehem, PA, United States
| | - Julie S Haas
- Department of Biological Sciences, Lehigh University, Bethlehem, PA, United States
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22
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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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Aldworth ZN, Stopfer M. Insect neuroscience: Filling the knowledge gap on gap junctions. Curr Biol 2022; 32:R420-R423. [DOI: 10.1016/j.cub.2022.03.062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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24
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Ammer G, Vieira RM, Fendl S, Borst A. Anatomical distribution and functional roles of electrical synapses in Drosophila. Curr Biol 2022; 32:2022-2036.e4. [DOI: 10.1016/j.cub.2022.03.040] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 02/16/2022] [Accepted: 03/14/2022] [Indexed: 10/18/2022]
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25
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Welzel G, Schuster S. Connexins evolved after early chordates lost innexin diversity. eLife 2022; 11:74422. [PMID: 35042580 PMCID: PMC8769644 DOI: 10.7554/elife.74422] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 01/05/2022] [Indexed: 11/26/2022] Open
Abstract
Gap junction channels are formed by two unrelated protein families. Non-chordates use the primordial innexins, while chordates use connexins that superseded the gap junction function of innexins. Chordates retained innexin-homologs, but N-glycosylation prevents them from forming gap junctions. It is puzzling why chordates seem to exclusively use the new gap junction protein and why no chordates should exist that use non-glycosylated innexins to form gap junctions. Here, we identified glycosylation sites of 2388 innexins from 174 non-chordate and 276 chordate species. Among all chordates, we found not a single innexin without glycosylation sites. Surprisingly, the glycosylation motif is also widespread among non-chordate innexins indicating that glycosylated innexins are not a novelty of chordates. In addition, we discovered a loss of innexin diversity during early chordate evolution. Most importantly, lancelets, which lack connexins, exclusively possess only one highly conserved innexin with one glycosylation site. A bottleneck effect might thus explain why connexins have become the only protein used to form chordate gap junctions.
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Affiliation(s)
- Georg Welzel
- Department of Animal Physiology, University of Bayreuth
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26
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Piao C, Sigrist SJ. (M)Unc13s in Active Zone Diversity: A Drosophila Perspective. Front Synaptic Neurosci 2022; 13:798204. [PMID: 35046788 PMCID: PMC8762327 DOI: 10.3389/fnsyn.2021.798204] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 11/29/2021] [Indexed: 12/03/2022] Open
Abstract
The so-called active zones at pre-synaptic terminals are the ultimate filtering devices, which couple between action potential frequency and shape, and the information transferred to the post-synaptic neurons, finally tuning behaviors. Within active zones, the release of the synaptic vesicle operates from specialized “release sites.” The (M)Unc13 class of proteins is meant to define release sites topologically and biochemically, and diversity between Unc13-type release factor isoforms is suspected to steer diversity at active zones. The two major Unc13-type isoforms, namely, Unc13A and Unc13B, have recently been described from the molecular to the behavioral level, exploiting Drosophila being uniquely suited to causally link between these levels. The exact nanoscale distribution of voltage-gated Ca2+ channels relative to release sites (“coupling”) at pre-synaptic active zones fundamentally steers the release of the synaptic vesicle. Unc13A and B were found to be either tightly or loosely coupled across Drosophila synapses. In this review, we reported recent findings on diverse aspects of Drosophila Unc13A and B, importantly, their nano-topological distribution at active zones and their roles in release site generation, active zone assembly, and pre-synaptic homeostatic plasticity. We compared their stoichiometric composition at different synapse types, reviewing the correlation between nanoscale distribution of these two isoforms and release physiology and, finally, discuss how isoform-specific release components might drive the functional heterogeneity of synapses and encode discrete behavior.
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Affiliation(s)
- Chengji Piao
- Institute for Biology/Genetics, Freie Universität Berlin, Berlin, Germany
- NeuroCure Cluster of Excellence, Charité Universitätsmedizin, Berlin, Germany
| | - Stephan J. Sigrist
- Institute for Biology/Genetics, Freie Universität Berlin, Berlin, Germany
- NeuroCure Cluster of Excellence, Charité Universitätsmedizin, Berlin, Germany
- *Correspondence: Stephan J. Sigrist
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Fusca D, Kloppenburg P. Task-specific roles of local interneurons for inter- and intraglomerular signaling in the insect antennal lobe. eLife 2021; 10:65217. [PMID: 34554087 PMCID: PMC8460249 DOI: 10.7554/elife.65217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 09/09/2021] [Indexed: 11/13/2022] Open
Abstract
Local interneurons (LNs) mediate complex interactions within the antennal lobe, the primary olfactory system of insects, and the functional analog of the vertebrate olfactory bulb. In the cockroach Periplaneta americana, as in other insects, several types of LNs with distinctive physiological and morphological properties can be defined. Here, we combined whole-cell patch-clamp recordings and Ca2+ imaging of individual LNs to analyze the role of spiking and nonspiking LNs in inter- and intraglomerular signaling during olfactory information processing. Spiking GABAergic LNs reacted to odorant stimulation with a uniform rise in [Ca2+]i in the ramifications of all innervated glomeruli. In contrast, in nonspiking LNs, glomerular Ca2+ signals were odorant specific and varied between glomeruli, resulting in distinct, glomerulus-specific tuning curves. The cell type-specific differences in Ca2+ dynamics support the idea that spiking LNs play a primary role in interglomerular signaling, while they assign nonspiking LNs an essential role in intraglomerular signaling.
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Affiliation(s)
- Debora Fusca
- Biocenter, Institute for Zoology, and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Peter Kloppenburg
- Biocenter, Institute for Zoology, and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
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Das Chakraborty S, Sachse S. Olfactory processing in the lateral horn of Drosophila. Cell Tissue Res 2021; 383:113-123. [PMID: 33475851 PMCID: PMC7873099 DOI: 10.1007/s00441-020-03392-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 12/10/2020] [Indexed: 11/24/2022]
Abstract
Sensing olfactory signals in the environment represents a crucial and significant task of sensory systems in almost all organisms to facilitate survival and reproduction. Notably, the olfactory system of diverse animal phyla shares astonishingly many fundamental principles with regard to anatomical and functional properties. Binding of odor ligands by chemosensory receptors present in the olfactory peripheral organs leads to a neuronal activity that is conveyed to first and higher-order brain centers leading to a subsequent odor-guided behavioral decision. One of the key centers for integrating and processing innate olfactory behavior is the lateral horn (LH) of the protocerebrum in insects. In recent years the LH of Drosophila has garnered increasing attention and many studies have been dedicated to elucidate its circuitry. In this review we will summarize the recent advances in mapping and characterizing LH-specific cell types, their functional properties with respect to odor tuning, their neurotransmitter profiles, their connectivity to pre-synaptic and post-synaptic partner neurons as well as their impact for olfactory behavior as known so far.
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Affiliation(s)
- Sudeshna Das Chakraborty
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Hans-Knoell-Str. 8, 07745, Jena, Germany
| | - Silke Sachse
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Hans-Knoell-Str. 8, 07745, Jena, Germany.
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Rabinowitch I, Upadhyaya B, Pant A, Galski D, Kreines L, Bai J. Circumventing neural damage in a C. elegans chemosensory circuit using genetically engineered synapses. Cell Syst 2021; 12:263-271.e4. [PMID: 33472027 DOI: 10.1016/j.cels.2020.12.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 11/03/2020] [Accepted: 12/22/2020] [Indexed: 10/22/2022]
Abstract
Neuronal loss can considerably diminish neural circuit function, impairing normal behavior by disrupting information flow in the circuit. Here, we use genetically engineered electrical synapses to reroute the flow of information in a C. elegans damaged chemosensory circuit in order to restore organism behavior. We impaired chemotaxis by removing one pair of interneurons from the circuit then artificially coupled two other adjacent neuron pairs by ectopically expressing the gap junction protein, connexin, in them. This restored chemotaxis in the animals. We expected to observe linear and direct information flow between the connexin-coupled neurons in the recovered circuit but also revealed the formation of new potent left-right lateral electrical connections within the connexin-expressing neuron pairs. Our analysis suggests that these additional electrical synapses help restore circuit function by amplifying weakened neuronal signals in the damaged circuit in addition to emulating the wild-type circuit. A record of this paper's transparent peer review process is included in the Supplemental Information.
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Affiliation(s)
- Ithai Rabinowitch
- Department of Medical Neurobiology, IMRIC - Institute for Medical Research Israel-Canada, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 9112002, Israel.
| | - Bishal Upadhyaya
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Aaradhya Pant
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Dolev Galski
- Department of Medical Neurobiology, IMRIC - Institute for Medical Research Israel-Canada, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 9112002, Israel
| | - Lena Kreines
- Department of Medical Neurobiology, IMRIC - Institute for Medical Research Israel-Canada, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 9112002, Israel
| | - Jihong Bai
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA.
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30
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Fuscà D, Kloppenburg P. Odor processing in the cockroach antennal lobe-the network components. Cell Tissue Res 2021; 383:59-73. [PMID: 33486607 PMCID: PMC7872951 DOI: 10.1007/s00441-020-03387-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 12/07/2020] [Indexed: 02/06/2023]
Abstract
Highly interconnected neural networks perform olfactory signal processing in the central nervous system. In insects, the first synaptic processing of the olfactory input from the antennae occurs in the antennal lobe, the functional equivalent of the olfactory bulb in vertebrates. Key components of the olfactory network in the antennal lobe are two main types of neurons: the local interneurons and the projection (output) neurons. Both neuron types have different physiological tasks during olfactory processing, which accordingly require specialized functional phenotypes. This review gives an overview of important cell type-specific functional properties of the different types of projection neurons and local interneurons in the antennal lobe of the cockroach Periplaneta americana, which is an experimental system that has elucidated many important biophysical and cellular bases of intrinsic physiological properties of these neurons.
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Affiliation(s)
- Debora Fuscà
- Biocenter, Institute for Zoology, and Cologne Excellence Cluster On Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Zülpicher Str. 47b, 50674, Cologne, Germany
| | - Peter Kloppenburg
- Biocenter, Institute for Zoology, and Cologne Excellence Cluster On Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Zülpicher Str. 47b, 50674, Cologne, Germany.
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31
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Neuronal architecture of the second-order CO 2 pathway in the brain of a noctuid moth. Sci Rep 2020; 10:19838. [PMID: 33199810 PMCID: PMC7669840 DOI: 10.1038/s41598-020-76918-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 11/04/2020] [Indexed: 12/17/2022] Open
Abstract
Many insects possess the ability to detect fine fluctuations in the environmental CO2 concentration. In herbivorous species, plant-emitted CO2, in combination with other sensory cues, affect many behaviors including foraging and oviposition. In contrast to the comprehensive knowledge obtained on the insect olfactory pathway in recent years, we still know little about the central CO2 system. By utilizing intracellular labeling and mass staining, we report the neuroanatomy of projection neurons connected with the CO2 sensitive antennal-lobe glomerulus, the labial pit organ glomerulus (LPOG), in the noctuid moth, Helicoverpa armigera. We identified 15 individual LPOG projection neurons passing along different tracts. Most of these uniglomerular neurons terminated in the lateral horn, a previously well-described target area of plant-odor projection neurons originating from the numerous ordinary antennal-lobe glomeruli. The other higher-order processing area for odor information, the calyces, on the other hand, was weakly innervated by the LPOG neurons. The overlapping LPOG terminals in the lateral horn, which is considered important for innate behavior in insects, suggests the biological importance of integrating the CO2 input with plant odor information while the weak innervation of the calyces indicates the insignificance of this ubiquitous cue for learning mechanisms.
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32
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Coates KE, Calle-Schuler SA, Helmick LM, Knotts VL, Martik BN, Salman F, Warner LT, Valla SV, Bock DD, Dacks AM. The Wiring Logic of an Identified Serotonergic Neuron That Spans Sensory Networks. J Neurosci 2020; 40:6309-6327. [PMID: 32641403 PMCID: PMC7424878 DOI: 10.1523/jneurosci.0552-20.2020] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 06/16/2020] [Accepted: 06/25/2020] [Indexed: 12/21/2022] Open
Abstract
Serotonergic neurons project widely throughout the brain to modulate diverse physiological and behavioral processes. However, a single-cell resolution understanding of the connectivity of serotonergic neurons is currently lacking. Using a whole-brain EM dataset of a female Drosophila, we comprehensively determine the wiring logic of a broadly projecting serotonergic neuron (the CSDn) that spans several olfactory regions. Within the antennal lobe, the CSDn differentially innervates each glomerulus, yet surprisingly, this variability reflects a diverse set of presynaptic partners, rather than glomerulus-specific differences in synaptic output, which is predominately to local interneurons. Moreover, the CSDn has distinct connectivity relationships with specific local interneuron subtypes, suggesting that the CSDn influences distinct aspects of local network processing. Across olfactory regions, the CSDn has different patterns of connectivity, even having different connectivity with individual projection neurons that also span these regions. Whereas the CSDn targets inhibitory local neurons in the antennal lobe, the CSDn has more distributed connectivity in the LH, preferentially synapsing with principal neuron types based on transmitter content. Last, we identify individual novel synaptic partners associated with other sensory domains that provide strong, top-down input to the CSDn. Together, our study reveals the complex connectivity of serotonergic neurons, which combine the integration of local and extrinsic synaptic input in a nuanced, region-specific manner.SIGNIFICANCE STATEMENT All sensory systems receive serotonergic modulatory input. However, a comprehensive understanding of the synaptic connectivity of individual serotonergic neurons is lacking. In this study, we use a whole-brain EM microscopy dataset to comprehensively determine the wiring logic of a broadly projecting serotonergic neuron in the olfactory system of Drosophila Collectively, our study demonstrates, at a single-cell level, the complex connectivity of serotonergic neurons within their target networks, identifies specific cell classes heavily targeted for serotonergic modulation in the olfactory system, and reveals novel extrinsic neurons that provide strong input to this serotonergic system outside of the context of olfaction. Elucidating the connectivity logic of individual modulatory neurons provides a ground plan for the seemingly heterogeneous effects of modulatory systems.
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Affiliation(s)
- Kaylynn E Coates
- Department of Biology, West Virginia University, Morgantown, West Virginia 26506
| | | | - Levi M Helmick
- Department of Biology, West Virginia University, Morgantown, West Virginia 26506
| | - Victoria L Knotts
- Department of Biology, West Virginia University, Morgantown, West Virginia 26506
| | - Brennah N Martik
- Department of Biology, West Virginia University, Morgantown, West Virginia 26506
| | - Farzaan Salman
- Department of Biology, West Virginia University, Morgantown, West Virginia 26506
| | - Lauren T Warner
- Department of Biology, West Virginia University, Morgantown, West Virginia 26506
| | - Sophia V Valla
- Department of Biology, West Virginia University, Morgantown, West Virginia 26506
| | - Davi D Bock
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia 20147
- Department of Neurological Sciences, Larner College of Medicine, University of Vermont, Burlington, Vermont 05405
| | - Andrew M Dacks
- Department of Biology, West Virginia University, Morgantown, West Virginia 26506
- Department of Neuroscience, West Virginia University, Morgantown, West Virginia 26506
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Sizemore TR, Hurley LM, Dacks AM. Serotonergic modulation across sensory modalities. J Neurophysiol 2020; 123:2406-2425. [PMID: 32401124 PMCID: PMC7311732 DOI: 10.1152/jn.00034.2020] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 05/04/2020] [Accepted: 05/12/2020] [Indexed: 12/24/2022] Open
Abstract
The serotonergic system has been widely studied across animal taxa and different functional networks. This modulatory system is therefore well positioned to compare the consequences of neuromodulation for sensory processing across species and modalities at multiple levels of sensory organization. Serotonergic neurons that innervate sensory networks often bidirectionally exchange information with these networks but also receive input representative of motor events or motivational state. This convergence of information supports serotonin's capacity for contextualizing sensory information according to the animal's physiological state and external events. At the level of sensory circuitry, serotonin can have variable effects due to differential projections across specific sensory subregions, as well as differential serotonin receptor type expression within those subregions. Functionally, this infrastructure may gate or filter sensory inputs to emphasize specific stimulus features or select among different streams of information. The near-ubiquitous presence of serotonin and other neuromodulators within sensory regions, coupled with their strong effects on stimulus representation, suggests that these signaling pathways should be considered integral components of sensory systems.
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Affiliation(s)
- Tyler R Sizemore
- Department of Biology, West Virginia University, Morgantown, West Virginia
| | - Laura M Hurley
- Department of Biology, Indiana University, Bloomington, Indiana
| | - Andrew M Dacks
- Department of Biology, West Virginia University, Morgantown, West Virginia
- Department of Neuroscience, West Virginia University, Morgantown, West Virginia
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34
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Martin EA, Lasseigne AM, Miller AC. Understanding the Molecular and Cell Biological Mechanisms of Electrical Synapse Formation. Front Neuroanat 2020; 14:12. [PMID: 32372919 PMCID: PMC7179694 DOI: 10.3389/fnana.2020.00012] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Accepted: 03/09/2020] [Indexed: 12/20/2022] Open
Abstract
In this review article, we will describe the recent advances made towards understanding the molecular and cell biological mechanisms of electrical synapse formation. New evidence indicates that electrical synapses, which are gap junctions between neurons, can have complex molecular compositions including protein asymmetries across joined cells, diverse morphological arrangements, and overlooked similarities with other junctions, all of which indicate new potential roles in neurodevelopmental disease. Aquatic organisms, and in particular the vertebrate zebrafish, have proven to be excellent models for elucidating the molecular mechanisms of electrical synapse formation. Zebrafish will serve as our main exemplar throughout this review and will be compared with other model organisms. We highlight the known cell biological processes that build neuronal gap junctions and compare these with the assemblies of adherens junctions, tight junctions, non-neuronal gap junctions, and chemical synapses to explore the unknown frontiers remaining in our understanding of the critical and ubiquitous electrical synapse.
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Affiliation(s)
- E Anne Martin
- Department of Biology, Institute of Neuroscience, University of Oregon, Eugene, OR, United States
| | - Abagael M Lasseigne
- Department of Biology, Institute of Neuroscience, University of Oregon, Eugene, OR, United States
| | - Adam C Miller
- Department of Biology, Institute of Neuroscience, University of Oregon, Eugene, OR, United States
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35
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Amin H, Lin AC. Neuronal mechanisms underlying innate and learned olfactory processing in Drosophila. CURRENT OPINION IN INSECT SCIENCE 2019; 36:9-17. [PMID: 31280185 DOI: 10.1016/j.cois.2019.06.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Accepted: 06/03/2019] [Indexed: 06/09/2023]
Abstract
Olfaction allows animals to adapt their behavior in response to different chemical cues in their environment. How does the brain efficiently discriminate different odors to drive appropriate behavior, and how does it flexibly assign value to odors to adjust behavior according to experience? This review traces neuronal mechanisms underlying these processes in adult Drosophila melanogaster from olfactory receptors to higher brain centers. We highlight neural circuit principles such as lateral inhibition, segregation and integration of olfactory channels, temporal accumulation of sensory evidence, and compartmentalized synaptic plasticity underlying associative memory.
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Affiliation(s)
- Hoger Amin
- Department of Biomedical Science, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, United Kingdom
| | - Andrew C Lin
- Department of Biomedical Science, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, United Kingdom.
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36
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Storace DA, Cohen LB, Choi Y. Using Genetically Encoded Voltage Indicators (GEVIs) to Study the Input-Output Transformation of the Mammalian Olfactory Bulb. Front Cell Neurosci 2019; 13:342. [PMID: 31417362 PMCID: PMC6684792 DOI: 10.3389/fncel.2019.00342] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 07/11/2019] [Indexed: 12/19/2022] Open
Abstract
Genetically encoded voltage indicators (GEVIs) are fluorescent protein reporters of membrane potential. These tools can, in principle, be used to monitor the neural activity of genetically distinct cell types in the brain. Although introduced in 1997, they have been a challenge to use to study intact neural circuits due to a combination of small signal-to-noise ratio, slow kinetics, and poor membrane expression. New strategies have yielded novel GEVIs such as ArcLight, which have improved properties. Here, we compare the in vivo properties of ArcLight with Genetically Encoded Calcium Indicators (GECIs) in the mouse olfactory bulb. We show how voltage imaging can be combined with organic calcium sensitive dyes to measure the input-output transformation of the olfactory bulb. Finally, we demonstrate that ArcLight can be targeted to olfactory bulb interneurons. The olfactory bulb contributes substantially to the perception of the concentration invariance of odor recognition.
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Affiliation(s)
- Douglas A Storace
- Department of Biological Science, Florida State University, Tallahassee, FL, United States.,Department of Cellular and Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT, United States
| | - Lawrence B Cohen
- Department of Cellular and Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT, United States.,Center for Functional Connectomics, Korea Institute of Science and Technology, Seoul, South Korea
| | - Yunsook Choi
- Department of Cellular and Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT, United States.,Center for Functional Connectomics, Korea Institute of Science and Technology, Seoul, South Korea
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37
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Raad H, Robichon A. The pleiotropic effects of Innexin genes expressed in Drosophila glia encompass wing chemosensory sensilla. J Neurosci Res 2019; 97:1319-1330. [PMID: 31257643 DOI: 10.1002/jnr.24485] [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: 03/04/2019] [Revised: 06/05/2019] [Accepted: 06/07/2019] [Indexed: 11/07/2022]
Abstract
The neuroanatomy of Drosophila wing chemosensilla and the analysis of their sensory organ precursor cell lineage have demonstrated that they are surprisingly related to taste perception. The microarchitecture of wing bristles limits the use of electrophysiology methods to investigate wing chemosensory mechanisms. However, by monitoring the fluorescence of the complex calcium/GCaMP, calcium flux triggered upon tastant stimulation was observed within sensilla aligned along the wing anterior nerve. This string of fluorescent puncta was impaired in wings of Innexin 2 (Inx2) mutant flies; although it is unclear whether the Innexin proteins act at the level of the wing imaginal disc, adult wing and/or at both levels. Glial cells known to shelter Innexin(s) expression have no documented role in adult chemosensory sensilla. Our data suggest that Innexin(s) are likely required for the maturation of functional wing chemosensilla in adulthood. The unexpected presence of most Innexin transcripts in adult wing RNAseq data set argues for the expression of Innexin proteins in the larval imaginal wing disc that are continued in wing chemosensilla at adulthood. OPEN PRACTICES: This article has earned an Open Data badge for making publicly available the digitally-shareable data necessary to reproduce the reported results. The data is available as supporting materials and includes the electronic lab notebook. Learn more about the Open Practices badges from the Center for Open Science: https://osf.io/tvyxz/wiki.
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Affiliation(s)
- Hussein Raad
- INRA, CNRS, Université Côte d'Azur, Institut Sophia Agrobiotech, Sophia Antipolis, France.,Lebanese International University, Mazraa, Lebanon
| | - Alain Robichon
- INRA, CNRS, Université Côte d'Azur, Institut Sophia Agrobiotech, Sophia Antipolis, France
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38
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Martelli C, Fiala A. Slow presynaptic mechanisms that mediate adaptation in the olfactory pathway of Drosophila. eLife 2019; 8:43735. [PMID: 31169499 PMCID: PMC6581506 DOI: 10.7554/elife.43735] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2018] [Accepted: 06/05/2019] [Indexed: 12/14/2022] Open
Abstract
The olfactory system encodes odor stimuli as combinatorial activity of populations of neurons whose response depends on stimulus history. How and on which timescales previous stimuli affect these combinatorial representations remains unclear. We use in vivo optical imaging in Drosophila to analyze sensory adaptation at the first synaptic step along the olfactory pathway. We show that calcium signals in the axon terminals of olfactory receptor neurons (ORNs) do not follow the same adaptive properties as the firing activity measured at the antenna. While ORNs calcium responses are sustained on long timescales, calcium signals in the postsynaptic projection neurons (PNs) adapt within tens of seconds. We propose that this slow component of the postsynaptic response is mediated by a slow presynaptic depression of vesicle release and enables the combinatorial population activity of PNs to adjust to the mean and variance of fluctuating odor stimuli.
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Affiliation(s)
- Carlotta Martelli
- Molecular Neurobiology of Behavior, Johann-Friedrich-Blumenbach-Institute for Zoology and Anthropology, University of Goettingen, Goettingen, Germany.,Department of Biology, Neurobiology, University of Konstanz, Konstanz, Germany
| | - André Fiala
- Molecular Neurobiology of Behavior, Johann-Friedrich-Blumenbach-Institute for Zoology and Anthropology, University of Goettingen, Goettingen, Germany
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39
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Dolan MJ, Frechter S, Bates AS, Dan C, Huoviala P, Roberts RJV, Schlegel P, Dhawan S, Tabano R, Dionne H, Christoforou C, Close K, Sutcliffe B, Giuliani B, Li F, Costa M, Ihrke G, Meissner GW, Bock DD, Aso Y, Rubin GM, Jefferis GSXE. Neurogenetic dissection of the Drosophila lateral horn reveals major outputs, diverse behavioural functions, and interactions with the mushroom body. eLife 2019; 8:e43079. [PMID: 31112130 PMCID: PMC6529221 DOI: 10.7554/elife.43079] [Citation(s) in RCA: 84] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 02/07/2019] [Indexed: 01/26/2023] Open
Abstract
Animals exhibit innate behaviours to a variety of sensory stimuli including olfactory cues. In Drosophila, one higher olfactory centre, the lateral horn (LH), is implicated in innate behaviour. However, our structural and functional understanding of the LH is scant, in large part due to a lack of sparse neurogenetic tools for this region. We generate a collection of split-GAL4 driver lines providing genetic access to 82 LH cell types. We use these to create an anatomical and neurotransmitter map of the LH and link this to EM connectomics data. We find ~30% of LH projections converge with outputs from the mushroom body, site of olfactory learning and memory. Using optogenetic activation, we identify LH cell types that drive changes in valence behavior or specific locomotor programs. In summary, we have generated a resource for manipulating and mapping LH neurons, providing new insights into the circuit basis of innate and learned olfactory behavior.
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Affiliation(s)
- Michael-John Dolan
- Howard Hughes Medical Institute, Janelia Research CampusAshburnUnited States
- Division of NeurobiologyMRC Laboratory of Molecular BiologyCambridgeUnited Kingdom
| | - Shahar Frechter
- Division of NeurobiologyMRC Laboratory of Molecular BiologyCambridgeUnited Kingdom
| | | | - Chuntao Dan
- Howard Hughes Medical Institute, Janelia Research CampusAshburnUnited States
| | - Paavo Huoviala
- Division of NeurobiologyMRC Laboratory of Molecular BiologyCambridgeUnited Kingdom
| | | | - Philipp Schlegel
- Division of NeurobiologyMRC Laboratory of Molecular BiologyCambridgeUnited Kingdom
- Department of ZoologyUniversity of CambridgeCambridgeUnited Kingdom
| | - Serene Dhawan
- Division of NeurobiologyMRC Laboratory of Molecular BiologyCambridgeUnited Kingdom
- Department of ZoologyUniversity of CambridgeCambridgeUnited Kingdom
| | - Remy Tabano
- Howard Hughes Medical Institute, Janelia Research CampusAshburnUnited States
| | - Heather Dionne
- Howard Hughes Medical Institute, Janelia Research CampusAshburnUnited States
| | | | - Kari Close
- Howard Hughes Medical Institute, Janelia Research CampusAshburnUnited States
| | - Ben Sutcliffe
- Division of NeurobiologyMRC Laboratory of Molecular BiologyCambridgeUnited Kingdom
| | - Bianca Giuliani
- Howard Hughes Medical Institute, Janelia Research CampusAshburnUnited States
| | - Feng Li
- Howard Hughes Medical Institute, Janelia Research CampusAshburnUnited States
| | - Marta Costa
- Department of ZoologyUniversity of CambridgeCambridgeUnited Kingdom
| | - Gudrun Ihrke
- Howard Hughes Medical Institute, Janelia Research CampusAshburnUnited States
| | | | - Davi D Bock
- Howard Hughes Medical Institute, Janelia Research CampusAshburnUnited States
| | - Yoshinori Aso
- Howard Hughes Medical Institute, Janelia Research CampusAshburnUnited States
| | - Gerald M Rubin
- Howard Hughes Medical Institute, Janelia Research CampusAshburnUnited States
| | - Gregory SXE Jefferis
- Howard Hughes Medical Institute, Janelia Research CampusAshburnUnited States
- Division of NeurobiologyMRC Laboratory of Molecular BiologyCambridgeUnited Kingdom
- Department of ZoologyUniversity of CambridgeCambridgeUnited Kingdom
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40
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Mohamed AAM, Retzke T, Das Chakraborty S, Fabian B, Hansson BS, Knaden M, Sachse S. Odor mixtures of opposing valence unveil inter-glomerular crosstalk in the Drosophila antennal lobe. Nat Commun 2019; 10:1201. [PMID: 30867415 PMCID: PMC6416470 DOI: 10.1038/s41467-019-09069-1] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 02/20/2019] [Indexed: 12/17/2022] Open
Abstract
Evaluating odor blends in sensory processing is a crucial step for signal recognition and execution of behavioral decisions. Using behavioral assays and 2-photon imaging, we have characterized the neural and behavioral correlates of mixture perception in the olfactory system of Drosophila. Mixtures of odors with opposing valences elicit strong inhibition in certain attractant-responsive input channels. This inhibition correlates with reduced behavioral attraction. We demonstrate that defined subsets of GABAergic interneurons provide the neuronal substrate of this computation at pre- and postsynaptic loci via GABAB- and GABAA receptors, respectively. Intriguingly, manipulation of single input channels by silencing and optogenetic activation unveils a glomerulus-specific crosstalk between the attractant- and repellent-responsive circuits. This inhibitory interaction biases the behavioral output. Such a form of selective lateral inhibition represents a crucial neuronal mechanism in the processing of conflicting sensory information.
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Affiliation(s)
- Ahmed A M Mohamed
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Hans-Knoell-Str. 8, 07745, Jena, Germany
| | - Tom Retzke
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Hans-Knoell-Str. 8, 07745, Jena, Germany
| | - Sudeshna Das Chakraborty
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Hans-Knoell-Str. 8, 07745, Jena, Germany
| | - Benjamin Fabian
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Hans-Knoell-Str. 8, 07745, Jena, Germany
| | - Bill S Hansson
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Hans-Knoell-Str. 8, 07745, Jena, Germany
| | - Markus Knaden
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Hans-Knoell-Str. 8, 07745, Jena, Germany
| | - Silke Sachse
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Hans-Knoell-Str. 8, 07745, Jena, Germany.
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41
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Abstract
A new genetically encoded system manipulates the pH inside cells to detect whether they are coupled to each other.
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Affiliation(s)
- Daniel R Kick
- Division of Biological Sciences, University of Missouri-Columbia, Columbia, United States
| | - David J Schulz
- Division of Biological Sciences, University of Missouri-Columbia, Columbia, United States
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42
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Groschner LN, Miesenböck G. Mechanisms of Sensory Discrimination: Insights from Drosophila Olfaction. Annu Rev Biophys 2019; 48:209-229. [PMID: 30786228 DOI: 10.1146/annurev-biophys-052118-115655] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
All an animal can do to infer the state of its environment is to observe the sensory-evoked activity of its own neurons. These inferences about the presence, quality, or similarity of objects are probabilistic and inform behavioral decisions that are often made in close to real time. Neural systems employ several strategies to facilitate sensory discrimination: Biophysical mechanisms separate the neuronal response distributions in coding space, compress their variances, and combine information from sequential observations. We review how these strategies are implemented in the olfactory system of the fruit fly. The emerging principles of odor discrimination likely apply to other neural circuits of similar architecture.
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Affiliation(s)
- Lukas N Groschner
- Centre for Neural Circuits and Behavior, University of Oxford, Oxford OX1 3SR, United Kingdom;
| | - Gero Miesenböck
- Centre for Neural Circuits and Behavior, University of Oxford, Oxford OX1 3SR, United Kingdom;
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43
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Activity-Dependent Remodeling of Drosophila Olfactory Sensory Neuron Brain Innervation during an Early-Life Critical Period. J Neurosci 2019; 39:2995-3012. [PMID: 30755492 DOI: 10.1523/jneurosci.2223-18.2019] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 01/07/2019] [Accepted: 02/03/2019] [Indexed: 12/12/2022] Open
Abstract
Critical periods are windows of development when the environment has a pronounced effect on brain circuitry. Models of neurodevelopmental disorders, including autism spectrum disorders, intellectual disabilities, and schizophrenia, are linked to disruption of critical period remodeling. Critical periods open with the onset of sensory experience; however, it remains unclear exactly how sensory input modifies brain circuits. Here, we examine olfactory sensory neuron (OSN) innervation of the Drosophila antennal lobe of both sexes as a genetic model of this question. We find that olfactory sensory experience during an early-use critical period drives loss of OSN innervation of antennal lobe glomeruli and subsequent axon retraction in a dose-dependent mechanism. This remodeling does not result from olfactory receptor loss or OSN degeneration, but rather from rapid synapse elimination and axon pruning in the target olfactory glomerulus. Removal of the odorant stimulus only during the critical period leads to OSN reinnervation, demonstrating that remodeling is transiently reversible. We find that this synaptic refinement requires the OSN-specific olfactory receptor and downstream activity. Conversely, blocking OSN synaptic output elevates glomeruli remodeling. We find that GABAergic neurotransmission has no detectable role, but that glutamatergic signaling via NMDA receptors is required for OSN synaptic refinement. Together, these results demonstrate that OSN inputs into the brain manifest robust, experience-dependent remodeling during an early-life critical period, which requires olfactory reception, OSN activity, and NMDA receptor signaling. This work reveals a pathway linking initial olfactory sensory experience to glutamatergic neurotransmission in the activity-dependent remodeling of brain neural circuitry in an early-use critical period.SIGNIFICANCE STATEMENT Neurodevelopmental disorders manifest symptoms at specific developmental milestones that suggest an intersection between early sensory experience and brain neural circuit remodeling. One classic example is Fragile X syndrome caused by loss of an RNA-binding translation regulator of activity-dependent synaptic refinement. As a model, Drosophila olfactory circuitry is well characterized, genetically tractable, and rapidly developing, and thus ideally suited to probe underlying mechanisms. Here, we find olfactory sensory neurons are dramatically remodeled by heightened sensory experience during an early-life critical period. We demonstrate removing the olfactory stimulus during the critical period can reverse the connectivity changes. We find that this remodeling requires neural activity and NMDA receptor-mediated glutamatergic transmission. This improved understanding may help us design treatments for neurodevelopmental disorders.
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44
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Wu L, Dong A, Dong L, Wang SQ, Li Y. PARIS, an optogenetic method for functionally mapping gap junctions. eLife 2019; 8:43366. [PMID: 30638447 PMCID: PMC6396999 DOI: 10.7554/elife.43366] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2018] [Accepted: 01/12/2019] [Indexed: 12/29/2022] Open
Abstract
Cell-cell communication via gap junctions regulates a wide range of physiological processes by enabling the direct intercellular electrical and chemical coupling. However, the in vivo distribution and function of gap junctions remain poorly understood, partly due to the lack of non-invasive tools with both cell-type specificity and high spatiotemporal resolution. Here, we developed PARIS (pairing actuators and receivers to optically isolate gap junctions), a new fully genetically encoded tool for measuring the cell-specific gap junctional coupling (GJC). PARIS successfully enabled monitoring of GJC in several cultured cell lines under physiologically relevant conditions and in distinct genetically defined neurons in Drosophila brain, with ~10 s temporal resolution and sub-cellular spatial resolution. These results demonstrate that PARIS is a robust, highly sensitive tool for mapping functional gap junctions and study their regulation in both health and disease. For the tissues and organs of our bodies to work properly, the cells within them need to communicate with each other. One important part of cellular communication is the movement of signals – usually small molecules or ions – directly from one cell to another. This happens via structures called gap junctions, a type of sealed ‘channel’ that connects two cells. Gap junctions are found throughout the body, but investigating their precise roles in health and disease has been difficult. This is due to problems with the tools available to detect and monitor gap junctions. Some are simply harmful to cells, while others cannot be restricted to specific cell populations within a tissue. This lack of specificity makes it difficult to study gap junctions in the brain, where it is important to understand the connectivity patterns between distinct types of nerve cells. Wu et al. wanted to develop a new, non-harmful method to track gap junctions in distinct groups of cells within living tissues. To do this, Wu et al. devised PARIS, a two-part, genetically encoded system. The first part comprises a light-sensitive molecular ‘pump’, which can only be turned on by shining a laser onto the cell of interest. When the pump is active, it transports hydrogen ions out of the cell. The second part of the system is a fluorescent sensor, present inside ‘receiving’ cells, which responds to the outcoming hydrogen ions (small enough to pass through gap junctions). If an illuminated ‘signaling’ cell is connected via gap junctions to cells containing the fluorescent sensor, they will light up within seconds, but other cells not connected through gap junctions will not. The researchers first tested PARIS in cultured human and rat cells that had been genetically engineered to produce both components of the system. The experiments confirmed that PARIS could both detect networks of gap junctions in healthy cells and reveal when these networks had been disrupted, for instance by drugs or genetic mutations. Experiments using fruit flies demonstrated that PARIS was stable in living tissue and could also map the gap junctions connecting specific groups of nerve cells. PARIS is a valuable addition to the toolbox available to study cell communication. In the future, it could help increase our understanding of diseases characterized by defective gap junctions, such as seizures, cardiac irregularities, and even some cancers.
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Affiliation(s)
- Ling Wu
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing, China.,PKU-IDG/McGovern Institute for Brain Research, Beijing, China.,Peking-Tsinghua Center for Life Sciences, Beijing, China
| | - Ao Dong
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing, China.,PKU-IDG/McGovern Institute for Brain Research, Beijing, China.,Peking-Tsinghua Center for Life Sciences, Beijing, China
| | - Liting Dong
- Peking-Tsinghua Center for Life Sciences, Beijing, China
| | - Shi-Qiang Wang
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing, China
| | - Yulong Li
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing, China.,PKU-IDG/McGovern Institute for Brain Research, Beijing, China.,Peking-Tsinghua Center for Life Sciences, Beijing, China.,Chinese Institute for Brain Research, Beijing, China
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45
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Semelidou O, Acevedo SF, Skoulakis EM. Temporally specific engagement of distinct neuronal circuits regulating olfactory habituation in Drosophila. eLife 2018; 7:39569. [PMID: 30576281 PMCID: PMC6303106 DOI: 10.7554/elife.39569] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 11/29/2018] [Indexed: 11/13/2022] Open
Abstract
Habituation is the process that enables salience filtering, precipitating perceptual changes that alter the value of environmental stimuli. To discern the neuronal circuits underlying habituation to brief inconsequential stimuli, we developed a novel olfactory habituation paradigm, identifying two distinct phases of the response that engage distinct neuronal circuits. Responsiveness to the continuous odor stimulus is maintained initially, a phase we term habituation latency and requires Rutabaga Adenylyl-Cyclase-depended neurotransmission from GABAergic Antennal Lobe Interneurons and activation of excitatory Projection Neurons (PNs) and the Mushroom Bodies. In contrast, habituation depends on the inhibitory PNs of the middle Antenno-Cerebral Track, requires inner Antenno-Cerebral Track PN activation and defines a temporally distinct phase. Collectively, our data support the involvement of Lateral Horn excitatory and inhibitory stimulation in habituation. These results provide essential cellular substrates for future analyses of the molecular mechanisms that govern the duration and transition between these distinct temporal habituation phases. Editorial note: This article has been through an editorial process in which the authors decide how to respond to the issues raised during peer review. The Reviewing Editor's assessment is that all the issues have been addressed (see decision letter).
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Affiliation(s)
- Ourania Semelidou
- Division of Neuroscience, Biomedical Sciences Research Centre "Alexander Fleming", Vari, Greece.,School of Medicine, University of Crete, Heraklion, Greece
| | - Summer F Acevedo
- Division of Neuroscience, Biomedical Sciences Research Centre "Alexander Fleming", Vari, Greece
| | - Efthimios Mc Skoulakis
- Division of Neuroscience, Biomedical Sciences Research Centre "Alexander Fleming", Vari, Greece
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46
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Eliason J, Afify A, Potter C, Matsumura I. A GAL80 Collection To Inhibit GAL4 Transgenes in Drosophila Olfactory Sensory Neurons. G3 (BETHESDA, MD.) 2018; 8:3661-3668. [PMID: 30262521 PMCID: PMC6222567 DOI: 10.1534/g3.118.200569] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 09/17/2018] [Indexed: 01/16/2023]
Abstract
Fruit flies recognize hundreds of ecologically relevant odors and respond appropriately to them. The complexity, redundancy and interconnectedness of the olfactory machinery complicate efforts to pinpoint the functional contributions of any component neuron or receptor to behavior. Some contributions can only be elucidated in flies that carry multiple mutations and transgenes, but the production of such flies is currently labor-intensive and time-consuming. Here, we describe a set of transgenic flies that express the Saccharomyces cerevisiae GAL80 in specific olfactory sensory neurons (OrX-GAL80s). The GAL80s effectively and specifically subtract the activities of GAL4-driven transgenes that impart anatomical and physiological phenotypes. OrX-GAL80s can allow researchers to efficiently activate only one or a few types of functional neurons in an otherwise nonfunctional olfactory background. Such experiments will improve our understanding of the mechanistic connections between odorant inputs and behavioral outputs at the resolution of only a few functional neurons.
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Affiliation(s)
- Jessica Eliason
- Janelia Research Campus, Howard Hughes Medical Institute' Ashburn, VA, 20147
- Department of Biochemistry; Emory University School of Medicine; Atlanta, GA, 30322
| | - Ali Afify
- Solomon H. Snyder Department of Neuroscience; Johns Hopkins University School of Medicine; Baltimore, MD, 21205
| | - Christopher Potter
- Solomon H. Snyder Department of Neuroscience; Johns Hopkins University School of Medicine; Baltimore, MD, 21205
| | - Ichiro Matsumura
- Department of Biochemistry; Emory University School of Medicine; Atlanta, GA, 30322
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47
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Welzel G, Schuster S. Long-term potentiation in an innexin-based electrical synapse. Sci Rep 2018; 8:12579. [PMID: 30135467 PMCID: PMC6105662 DOI: 10.1038/s41598-018-30966-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Accepted: 08/09/2018] [Indexed: 11/08/2022] Open
Abstract
Electrical synapses are formed by two unrelated gap junction protein families, the primordial innexins (invertebrates) or the connexins (vertebrates). Although molecularly different, innexin- and connexin-based electrical synapses are strikingly similar in their membrane topology. However, it remains unclear if this similarity extends also to more sophisticated functions such as long-term potentiation which is only known in connexin-based synapses. Here we show that this capacity is not unique to connexin-based synapses. Using a method that allowed us to quantitatively measure gap-junction conductance we provide the first and unequivocal evidence of long-term potentiation in an innexin-based electrical synapse. Our findings suggest that long-term potentiation is a property that has likely existed already in ancestral gap junctions. They therefore could provide a highly potent system to dissect shared molecular mechanisms of electrical synapse plasticity.
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Affiliation(s)
- Georg Welzel
- Department of Animal Physiology, University of Bayreuth, 95440, Bayreuth, Germany.
| | - Stefan Schuster
- Department of Animal Physiology, University of Bayreuth, 95440, Bayreuth, Germany.
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48
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Franconville R, Beron C, Jayaraman V. Building a functional connectome of the Drosophila central complex. eLife 2018; 7:e37017. [PMID: 30124430 PMCID: PMC6150698 DOI: 10.7554/elife.37017] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 08/14/2018] [Indexed: 01/27/2023] Open
Abstract
The central complex is a highly conserved insect brain region composed of morphologically stereotyped neurons that arborize in distinctively shaped substructures. The region is implicated in a wide range of behaviors and several modeling studies have explored its circuit computations. Most studies have relied on assumptions about connectivity between neurons based on their overlap in light microscopy images. Here, we present an extensive functional connectome of Drosophila melanogaster's central complex at cell-type resolution. Using simultaneous optogenetic stimulation, calcium imaging and pharmacology, we tested the connectivity between 70 presynaptic-to-postsynaptic cell-type pairs. We identified numerous inputs to the central complex, but only a small number of output channels. Additionally, the connectivity of this highly recurrent circuit appears to be sparser than anticipated from light microscopy images. Finally, the connectivity matrix highlights the potentially critical role of a class of bottleneck interneurons. All data are provided for interactive exploration on a website.
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Affiliation(s)
| | - Celia Beron
- Janelia Research CampusHoward Hughes Medical InstituteAshburnUnited States
| | - Vivek Jayaraman
- Janelia Research CampusHoward Hughes Medical InstituteAshburnUnited States
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49
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Liou NF, Lin SH, Chen YJ, Tsai KT, Yang CJ, Lin TY, Wu TH, Lin HJ, Chen YT, Gohl DM, Silies M, Chou YH. Diverse populations of local interneurons integrate into the Drosophila adult olfactory circuit. Nat Commun 2018; 9:2232. [PMID: 29884811 PMCID: PMC5993751 DOI: 10.1038/s41467-018-04675-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 05/14/2018] [Indexed: 11/09/2022] Open
Abstract
Drosophila olfactory local interneurons (LNs) in the antennal lobe are highly diverse and variable. How and when distinct types of LNs emerge, differentiate, and integrate into the olfactory circuit is unknown. Through systematic developmental analyses, we found that LNs are recruited to the adult olfactory circuit in three groups. Group 1 LNs are residual larval LNs. Group 2 are adult-specific LNs that emerge before cognate sensory and projection neurons establish synaptic specificity, and Group 3 LNs emerge after synaptic specificity is established. Group 1 larval LNs are selectively reintegrated into the adult circuit through pruning and re-extension of processes to distinct regions of the antennal lobe, while others die during metamorphosis. Precise temporal control of this pruning and cell death shapes the global organization of the adult antennal lobe. Our findings provide a road map to understand how LNs develop and contribute to constructing the olfactory circuit. Local interneurons (LNs) in the Drosophila olfactory system are highly diverse. Here, the authors labeled different LN types and described how different LN subtypes are integrated into the developing circuit.
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Affiliation(s)
- Nan-Fu Liou
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Shih-Han Lin
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Ying-Jun Chen
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Kuo-Ting Tsai
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Chi-Jen Yang
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Tzi-Yang Lin
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, 11529, Taiwan.,Research Institute of Molecular Pathology (IMP), Vienna Biocenter, Campus-Vienna-Biocenter 1, 1030, Vienna, Austria
| | - Ting-Han Wu
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Hsin-Ju Lin
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Yuh-Tarng Chen
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Daryl M Gohl
- Department of Neurobiology, Stanford University, Stanford, CA, 94305, USA.,University of Minnesota Genomics Center, 1-210 CCRB, 2231 6th Street SE, Minneapolis, MN, 55455, USA
| | - Marion Silies
- Department of Neurobiology, Stanford University, Stanford, CA, 94305, USA.,European Neuroscience Institute, University Medical Center Göttingen, Grisebachstr. 5, 37077, Göttingen, Germany
| | - Ya-Hui Chou
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, 11529, Taiwan. .,Neuroscience Program of Academia Sinica, Academia Sinica, Taipei, 11529, Taiwan.
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50
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Tsai KT, Hu CK, Li KW, Hwang WL, Chou YH. Circuit variability interacts with excitatory-inhibitory diversity of interneurons to regulate network encoding capacity. Sci Rep 2018; 8:8027. [PMID: 29795277 PMCID: PMC5966413 DOI: 10.1038/s41598-018-26286-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 05/09/2018] [Indexed: 01/15/2023] Open
Abstract
Local interneurons (LNs) in the Drosophila olfactory system exhibit neuronal diversity and variability, yet it is still unknown how these features impact information encoding capacity and reliability in a complex LN network. We employed two strategies to construct a diverse excitatory-inhibitory neural network beginning with a ring network structure and then introduced distinct types of inhibitory interneurons and circuit variability to the simulated network. The continuity of activity within the node ensemble (oscillation pattern) was used as a readout to describe the temporal dynamics of network activity. We found that inhibitory interneurons enhance the encoding capacity by protecting the network from extremely short activation periods when the network wiring complexity is very high. In addition, distinct types of interneurons have differential effects on encoding capacity and reliability. Circuit variability may enhance the encoding reliability, with or without compromising encoding capacity. Therefore, we have described how circuit variability of interneurons may interact with excitatory-inhibitory diversity to enhance the encoding capacity and distinguishability of neural networks. In this work, we evaluate the effects of different types and degrees of connection diversity on a ring model, which may simulate interneuron networks in the Drosophila olfactory system or other biological systems.
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Affiliation(s)
- Kuo-Ting Tsai
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan.,Institute of Physics, Academia Sinica, Taipei, Taiwan
| | - Chin-Kun Hu
- Institute of Physics, Academia Sinica, Taipei, Taiwan.,Neuroscience Program of Academia Sinica, Academia Sinica, Taipei, Taiwan.,National Center for Theoretical Sciences, National Tsing Hua University, Hsinchu, Taiwan.,Business School, University of Shanghai for Science and Technology, Shanghai, China
| | - Kuan-Wei Li
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan
| | - Wen-Liang Hwang
- Neuroscience Program of Academia Sinica, Academia Sinica, Taipei, Taiwan.,Institute of Information Science, Academia Sinica, Taipei, Taiwan
| | - Ya-Hui Chou
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan. .,Neuroscience Program of Academia Sinica, Academia Sinica, Taipei, Taiwan.
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