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Tello JA, Jiang L, Zohar Y, Restifo LL. Drosophila CASK regulates brain size and neuronal morphogenesis, providing a genetic model of postnatal microcephaly suitable for drug discovery. Neural Dev 2023; 18:6. [PMID: 37805506 PMCID: PMC10559581 DOI: 10.1186/s13064-023-00174-y] [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: 08/20/2023] [Accepted: 09/08/2023] [Indexed: 10/09/2023] Open
Abstract
BACKGROUND CASK-related neurodevelopmental disorders are untreatable. Affected children show variable severity, with microcephaly, intellectual disability (ID), and short stature as common features. X-linked human CASK shows dosage sensitivity with haploinsufficiency in females. CASK protein has multiple domains, binding partners, and proposed functions at synapses and in the nucleus. Human and Drosophila CASK show high amino-acid-sequence similarity in all functional domains. Flies homozygous for a hypomorphic CASK mutation (∆18) have motor and cognitive deficits. A Drosophila genetic model of CASK-related disorders could have great scientific and translational value. METHODS We assessed the effects of CASK loss of function on morphological phenotypes in Drosophila using established genetic, histological, and primary neuronal culture approaches. NeuronMetrics software was used to quantify neurite-arbor morphology. Standard nonparametric statistics methods were supplemented by linear mixed effects modeling in some cases. Microfluidic devices of varied dimensions were fabricated and numerous fluid-flow parameters were used to induce oscillatory stress fields on CNS tissue. Dissociation into viable neurons and neurite outgrowth in vitro were assessed. RESULTS We demonstrated that ∆18 homozygous flies have small brains, small heads, and short bodies. When neurons from developing CASK-mutant CNS were cultured in vitro, they grew small neurite arbors with a distinctive, quantifiable "bushy" morphology that was significantly rescued by transgenic CASK+. As in humans, the bushy phenotype showed dosage-sensitive severity. To overcome the limitations of manual tissue trituration for neuronal culture, we optimized the design and operation of a microfluidic system for standardized, automated dissociation of CNS tissue into individual viable neurons. Neurons from CASK-mutant CNS dissociated in the microfluidic system recapitulate the bushy morphology. Moreover, for any given genotype, device-dissociated neurons grew larger arbors than did manually dissociated neurons. This automated dissociation method is also effective for rodent CNS. CONCLUSIONS These biological and engineering advances set the stage for drug discovery using the Drosophila model of CASK-related disorders. The bushy phenotype provides a cell-based assay for compound screening. Nearly a dozen genes encoding CASK-binding proteins or transcriptional targets also have brain-development mutant phenotypes, including ID. Hence, drugs that improve CASK phenotypes might also benefit children with disorders due to mutant CASK partners.
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Affiliation(s)
- Judith A Tello
- Graduate Interdisciplinary Program in Neuroscience, University of Arizona, Tucson, AZ, 85721, USA
- Department of Neurology, University of Arizona Health Sciences, 1501 N. Campbell Ave, Tucson, AZ, 85724-5023, USA
- Present address: Department of Molecular Pathobiology, College of Dentistry, New York University, New York, NY, 10010, USA
| | - Linan Jiang
- Department of Aerospace and Mechanical Engineering, University of Arizona, Tucson, AZ, 85721, USA
| | - Yitshak Zohar
- Department of Aerospace and Mechanical Engineering, University of Arizona, Tucson, AZ, 85721, USA
- Department of Biomedical Engineering, University of Arizona, Tucson, AZ, 85721, USA
- BIO5 Interdisciplinary Research Institute, University of Arizona, Tucson, AZ, 85721, USA
| | - Linda L Restifo
- Graduate Interdisciplinary Program in Neuroscience, University of Arizona, Tucson, AZ, 85721, USA.
- Department of Neurology, University of Arizona Health Sciences, 1501 N. Campbell Ave, Tucson, AZ, 85724-5023, USA.
- BIO5 Interdisciplinary Research Institute, University of Arizona, Tucson, AZ, 85721, USA.
- Department of Cellular & Molecular Medicine, University of Arizona Health Sciences, Tucson, AZ, 85724, USA.
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Baccino-Calace M, Prieto D, Cantera R, Egger B. Compartment and cell-type specific hypoxia responses in the developing Drosophila brain. Biol Open 2020; 9:9/8/bio053629. [PMID: 32816692 PMCID: PMC7449796 DOI: 10.1242/bio.053629] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Environmental factors such as the availability of oxygen are instructive cues that regulate stem cell maintenance and differentiation. We used a genetically encoded biosensor to monitor the hypoxic state of neural cells in the larval brain of Drosophila. The biosensor reveals brain compartment and cell-type specific levels of hypoxia. The values correlate with differential tracheolation that is observed throughout development between the central brain and the optic lobe. Neural stem cells in both compartments show the strongest hypoxia response while intermediate progenitors, neurons and glial cells reveal weaker responses. We demonstrate that the distance between a cell and the next closest tracheole is a good predictor of the hypoxic state of that cell. Our study indicates that oxygen availability appears to be the major factor controlling the hypoxia response in the developing Drosophila brain and that cell intrinsic and cell-type specific factors contribute to modulate the response in an unexpected manner. This article has an associated First Person interview with the first author of the paper. Summary: A fluorescent biosensor reveals cell type specific hypoxia levels in the Drosophila brain in unprecedented detail. It paves the way for further functional studies addressing the role of oxygen in neural stem cell maintenance and differentiation.
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Affiliation(s)
- Martin Baccino-Calace
- Developmental Neurobiology, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo 11600, Uruguay
| | - Daniel Prieto
- Developmental Neurobiology, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo 11600, Uruguay
| | - Rafael Cantera
- Developmental Neurobiology, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo 11600, Uruguay.,Zoology Department, Stockholm University, Stockholm 106 91, Sweden
| | - Boris Egger
- Department of Biology, University of Fribourg, Fribourg CH-1700, Switzerland
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Itakura Y, Kohsaka H, Ohyama T, Zlatic M, Pulver SR, Nose A. Identification of Inhibitory Premotor Interneurons Activated at a Late Phase in a Motor Cycle during Drosophila Larval Locomotion. PLoS One 2015; 10:e0136660. [PMID: 26335437 PMCID: PMC4559423 DOI: 10.1371/journal.pone.0136660] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2015] [Accepted: 08/06/2015] [Indexed: 11/25/2022] Open
Abstract
Rhythmic motor patterns underlying many types of locomotion are thought to be produced by central pattern generators (CPGs). Our knowledge of how CPG networks generate motor patterns in complex nervous systems remains incomplete, despite decades of work in a variety of model organisms. Substrate borne locomotion in Drosophila larvae is driven by waves of muscular contraction that propagate through multiple body segments. We use the motor circuitry underlying crawling in larval Drosophila as a model to try to understand how segmentally coordinated rhythmic motor patterns are generated. Whereas muscles, motoneurons and sensory neurons have been well investigated in this system, far less is known about the identities and function of interneurons. Our recent study identified a class of glutamatergic premotor interneurons, PMSIs (period-positive median segmental interneurons), that regulate the speed of locomotion. Here, we report on the identification of a distinct class of glutamatergic premotor interneurons called Glutamatergic Ventro-Lateral Interneurons (GVLIs). We used calcium imaging to search for interneurons that show rhythmic activity and identified GVLIs as interneurons showing wave-like activity during peristalsis. Paired GVLIs were present in each abdominal segment A1-A7 and locally extended an axon towards a dorsal neuropile region, where they formed GRASP-positive putative synaptic contacts with motoneurons. The interneurons expressed vesicular glutamate transporter (vGluT) and thus likely secrete glutamate, a neurotransmitter known to inhibit motoneurons. These anatomical results suggest that GVLIs are premotor interneurons that locally inhibit motoneurons in the same segment. Consistent with this, optogenetic activation of GVLIs with the red-shifted channelrhodopsin, CsChrimson ceased ongoing peristalsis in crawling larvae. Simultaneous calcium imaging of the activity of GVLIs and motoneurons showed that GVLIs’ wave-like activity lagged behind that of motoneurons by several segments. Thus, GVLIs are activated when the front of a forward motor wave reaches the second or third anterior segment. We propose that GVLIs are part of the feedback inhibition system that terminates motor activity once the front of the motor wave proceeds to anterior segments.
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Affiliation(s)
- Yuki Itakura
- Department of Complexity Science and Engineering Graduate School of Frontier Sciences, The University of Tokyo, Kashiwanoha, Kashiwa, Chiba, Japan
| | - Hiroshi Kohsaka
- Department of Complexity Science and Engineering Graduate School of Frontier Sciences, The University of Tokyo, Kashiwanoha, Kashiwa, Chiba, Japan
| | - Tomoko Ohyama
- Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, United States of America
| | - Marta Zlatic
- Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, United States of America
| | - Stefan R Pulver
- Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, United States of America
| | - Akinao Nose
- Department of Complexity Science and Engineering Graduate School of Frontier Sciences, The University of Tokyo, Kashiwanoha, Kashiwa, Chiba, Japan; Department of Physics, Graduate School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, Japan
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Pulver SR, Bayley TG, Taylor AL, Berni J, Bate M, Hedwig B. Imaging fictive locomotor patterns in larval Drosophila. J Neurophysiol 2015; 114:2564-77. [PMID: 26311188 PMCID: PMC4637366 DOI: 10.1152/jn.00731.2015] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 08/24/2015] [Indexed: 11/22/2022] Open
Abstract
We have established a preparation in larval Drosophila to monitor fictive locomotion simultaneously across abdominal and thoracic segments of the isolated CNS with genetically encoded Ca2+ indicators. The Ca2+ signals closely followed spiking activity measured electrophysiologically in nerve roots. Three motor patterns are analyzed. Two comprise waves of Ca2+ signals that progress along the longitudinal body axis in a posterior-to-anterior or anterior-to-posterior direction. These waves had statistically indistinguishable intersegmental phase delays compared with segmental contractions during forward and backward crawling behavior, despite being ∼10 times slower. During these waves, motor neurons of the dorsal longitudinal and transverse muscles were active in the same order as the muscle groups are recruited during crawling behavior. A third fictive motor pattern exhibits a left-right asymmetry across segments and bears similarities with turning behavior in intact larvae, occurring equally frequently and involving asymmetry in the same segments. Ablation of the segments in which forward and backward waves of Ca2+ signals were normally initiated did not eliminate production of Ca2+ waves. When the brain and subesophageal ganglion (SOG) were removed, the remaining ganglia retained the ability to produce both forward and backward waves of motor activity, although the speed and frequency of waves changed. Bilateral asymmetry of activity was reduced when the brain was removed and abolished when the SOG was removed. This work paves the way to studying the neural and genetic underpinnings of segmentally coordinated motor pattern generation in Drosophila with imaging techniques.
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Affiliation(s)
- Stefan R Pulver
- School of Psychology and Neuroscience, University of St Andrews, St Andrews, United Kingdom; Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia
| | - Timothy G Bayley
- Department of Zoology, University of Cambridge, Cambridge, United Kingdom; and
| | - Adam L Taylor
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia
| | - Jimena Berni
- Department of Zoology, University of Cambridge, Cambridge, United Kingdom; and
| | - Michael Bate
- Department of Zoology, University of Cambridge, Cambridge, United Kingdom; and
| | - Berthold Hedwig
- Department of Zoology, University of Cambridge, Cambridge, United Kingdom; and
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5
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Whole-central nervous system functional imaging in larval Drosophila. Nat Commun 2015; 6:7924. [PMID: 26263051 PMCID: PMC4918770 DOI: 10.1038/ncomms8924] [Citation(s) in RCA: 126] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 06/25/2015] [Indexed: 12/21/2022] Open
Abstract
Understanding how the brain works in tight concert with the rest of the central nervous system (CNS) hinges upon knowledge of coordinated activity patterns across the whole CNS. We present a method for measuring activity in an entire, non-transparent CNS with high spatiotemporal resolution. We combine a light-sheet microscope capable of simultaneous multi-view imaging at volumetric speeds 25-fold faster than the state-of-the-art, a whole-CNS imaging assay for the isolated Drosophila larval CNS and a computational framework for analysing multi-view, whole-CNS calcium imaging data. We image both brain and ventral nerve cord, covering the entire CNS at 2 or 5 Hz with two- or one-photon excitation, respectively. By mapping network activity during fictive behaviours and quantitatively comparing high-resolution whole-CNS activity maps across individuals, we predict functional connections between CNS regions and reveal neurons in the brain that identify type and temporal state of motor programs executed in the ventral nerve cord. To understand how neuronal networks function, it is important to measure neuronal network activity at the systems level. Here Lemon et al. develop a framework that combines a high-speed multi-view light-sheet microscope, a whole-CNS imaging assay and computational tools to demonstrate simultaneous functional imaging across the entire isolated Drosophila larval CNS.
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6
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Venu I, Durisko Z, Xu J, Dukas R. Social attraction mediated by fruit flies' microbiome. ACTA ACUST UNITED AC 2015; 217:1346-52. [PMID: 24744425 DOI: 10.1242/jeb.099648] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Larval and adult fruit flies are attracted to volatiles emanating from food substrates that have been occupied by larvae. We tested whether such volatiles are emitted by the larval gut bacteria by conducting tests under bacteria-free (axenic) conditions. We also tested attraction to two bacteria species, Lactobacillus brevis, which we cultured from larvae in our lab, and L. plantarum, a common constituent of fruit flies' microbiome in other laboratory populations and in wild fruit flies. Neither larvae nor adults showed attraction to axenic food that had been occupied by axenic larvae, but both showed the previously reported attraction to standard food that had been occupied by larvae with an intact microbiome. Larvae also showed significant attraction to volatiles from axenic food and larvae to which we added only either L. brevis or L. plantarum, and volatiles from L. brevis reared on its optimal growth medium. Controlled learning experiments indicated that larvae experienced with both standard and axenic used food do not perceive either as superior, while focal larvae experienced with simulated used food, which contains burrows, perceive it as superior to unused food. Our results suggest that flies rely on microbiome-derived volatiles for long-distance attraction to suitable food patches. Under natural settings, fruits often contain harmful fungi and bacteria, and both L. brevis and L. plantarum produce compounds that suppress the growth of some antagonistic fungi and bacteria. The larval microbiome volatiles may therefore lead prospective fruit flies towards substrates with a hospitable microbial environment.
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Affiliation(s)
- Isvarya Venu
- Animal Behaviour Group, Department of Psychology, Neuroscience and Behaviour, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4K1, Canada
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7
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Food selection in larval fruit flies: dynamics and effects on larval development. Naturwissenschaften 2013; 101:61-8. [DOI: 10.1007/s00114-013-1129-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 12/04/2013] [Accepted: 12/05/2013] [Indexed: 02/07/2023]
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8
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The serotonergic central nervous system of the Drosophila larva: anatomy and behavioral function. PLoS One 2012; 7:e47518. [PMID: 23082175 PMCID: PMC3474743 DOI: 10.1371/journal.pone.0047518] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Accepted: 09/12/2012] [Indexed: 01/03/2023] Open
Abstract
The Drosophila larva has turned into a particularly simple model system for studying the neuronal basis of innate behaviors and higher brain functions. Neuronal networks involved in olfaction, gustation, vision and learning and memory have been described during the last decade, often up to the single-cell level. Thus, most of these sensory networks are substantially defined, from the sensory level up to third-order neurons. This is especially true for the olfactory system of the larva. Given the wealth of genetic tools in Drosophila it is now possible to address the question how modulatory systems interfere with sensory systems and affect learning and memory. Here we focus on the serotonergic system that was shown to be involved in mammalian and insect sensory perception as well as learning and memory. Larval studies suggested that the serotonergic system is involved in the modulation of olfaction, feeding, vision and heart rate regulation. In a dual anatomical and behavioral approach we describe the basic anatomy of the larval serotonergic system, down to the single-cell level. In parallel, by expressing apoptosis-inducing genes during embryonic and larval development, we ablate most of the serotonergic neurons within the larval central nervous system. When testing these animals for naïve odor, sugar, salt and light perception, no profound phenotype was detectable; even appetitive and aversive learning was normal. Our results provide the first comprehensive description of the neuronal network of the larval serotonergic system. Moreover, they suggest that serotonin per se is not necessary for any of the behaviors tested. However, our data do not exclude that this system may modulate or fine-tune a wide set of behaviors, similar to its reported function in other insect species or in mammals. Based on our observations and the availability of a wide variety of genetic tools, this issue can now be addressed.
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9
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Robinson BG, Khurana S, Pohl JB, Li WK, Ghezzi A, Cady AM, Najjar K, Hatch MM, Shah RR, Bhat A, Hariri O, Haroun KB, Young MC, Fife K, Hooten J, Tran T, Goan D, Desai F, Husain F, Godinez RM, Sun JC, Corpuz J, Moran J, Zhong AC, Chen WY, Atkinson NS. A low concentration of ethanol impairs learning but not motor and sensory behavior in Drosophila larvae. PLoS One 2012; 7:e37394. [PMID: 22624024 PMCID: PMC3356251 DOI: 10.1371/journal.pone.0037394] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2011] [Accepted: 04/22/2012] [Indexed: 11/18/2022] Open
Abstract
Drosophila melanogaster has proven to be a useful model system for the genetic analysis of ethanol-associated behaviors. However, past studies have focused on the response of the adult fly to large, and often sedating, doses of ethanol. The pharmacological effects of low and moderate quantities of ethanol have remained understudied. In this study, we tested the acute effects of low doses of ethanol (∼7 mM internal concentration) on Drosophila larvae. While ethanol did not affect locomotion or the response to an odorant, we observed that ethanol impaired associative olfactory learning when the heat shock unconditioned stimulus (US) intensity was low but not when the heat shock US intensity was high. We determined that the reduction in learning at low US intensity was not a result of ethanol anesthesia since ethanol-treated larvae responded to the heat shock in the same manner as untreated animals. Instead, low doses of ethanol likely impair the neuronal plasticity that underlies olfactory associative learning. This impairment in learning was reversible indicating that exposure to low doses of ethanol does not leave any long lasting behavioral or physiological effects.
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Affiliation(s)
- Brooks G. Robinson
- Section of Neurobiology, Institute for Neuroscience, The University of Texas at Austin, Austin, Texas, United States of America
| | - Sukant Khurana
- Section of Neurobiology, Institute for Neuroscience, The University of Texas at Austin, Austin, Texas, United States of America
| | - Jascha B. Pohl
- Section of Neurobiology, Institute for Neuroscience, The University of Texas at Austin, Austin, Texas, United States of America
| | - Wen-ke Li
- Section of Neurobiology, Institute for Neuroscience, The University of Texas at Austin, Austin, Texas, United States of America
| | - Alfredo Ghezzi
- Section of Neurobiology, Institute for Neuroscience, The University of Texas at Austin, Austin, Texas, United States of America
| | - Amanda M. Cady
- Section of Neurobiology, Institute for Neuroscience, The University of Texas at Austin, Austin, Texas, United States of America
| | - Kristina Najjar
- Section of Neurobiology, Institute for Neuroscience, The University of Texas at Austin, Austin, Texas, United States of America
| | - Michael M. Hatch
- Section of Neurobiology, Institute for Neuroscience, The University of Texas at Austin, Austin, Texas, United States of America
| | - Ruchita R. Shah
- Section of Neurobiology, Institute for Neuroscience, The University of Texas at Austin, Austin, Texas, United States of America
| | - Amar Bhat
- Section of Neurobiology, Institute for Neuroscience, The University of Texas at Austin, Austin, Texas, United States of America
| | - Omar Hariri
- Section of Neurobiology, Institute for Neuroscience, The University of Texas at Austin, Austin, Texas, United States of America
| | - Kareem B. Haroun
- Section of Neurobiology, Institute for Neuroscience, The University of Texas at Austin, Austin, Texas, United States of America
| | - Melvin C. Young
- Section of Neurobiology, Institute for Neuroscience, The University of Texas at Austin, Austin, Texas, United States of America
| | - Kathryn Fife
- Section of Neurobiology, Institute for Neuroscience, The University of Texas at Austin, Austin, Texas, United States of America
| | - Jeff Hooten
- Section of Neurobiology, Institute for Neuroscience, The University of Texas at Austin, Austin, Texas, United States of America
| | - Tuan Tran
- Section of Neurobiology, Institute for Neuroscience, The University of Texas at Austin, Austin, Texas, United States of America
| | - Daniel Goan
- Section of Neurobiology, Institute for Neuroscience, The University of Texas at Austin, Austin, Texas, United States of America
| | - Foram Desai
- Section of Neurobiology, Institute for Neuroscience, The University of Texas at Austin, Austin, Texas, United States of America
| | - Farhan Husain
- Section of Neurobiology, Institute for Neuroscience, The University of Texas at Austin, Austin, Texas, United States of America
| | - Ryan M. Godinez
- Section of Neurobiology, Institute for Neuroscience, The University of Texas at Austin, Austin, Texas, United States of America
| | - Jeffrey C. Sun
- Section of Neurobiology, Institute for Neuroscience, The University of Texas at Austin, Austin, Texas, United States of America
| | - Jonathan Corpuz
- Section of Neurobiology, Institute for Neuroscience, The University of Texas at Austin, Austin, Texas, United States of America
| | - Jacxelyn Moran
- Section of Neurobiology, Institute for Neuroscience, The University of Texas at Austin, Austin, Texas, United States of America
| | - Allen C. Zhong
- Section of Neurobiology, Institute for Neuroscience, The University of Texas at Austin, Austin, Texas, United States of America
| | - William Y. Chen
- Section of Neurobiology, Institute for Neuroscience, The University of Texas at Austin, Austin, Texas, United States of America
| | - Nigel S. Atkinson
- Section of Neurobiology, Institute for Neuroscience, The University of Texas at Austin, Austin, Texas, United States of America
- * E-mail:
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Active sensation during orientation behavior in the Drosophila larva: more sense than luck. Curr Opin Neurobiol 2011; 22:208-15. [PMID: 22169055 DOI: 10.1016/j.conb.2011.11.008] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2011] [Revised: 11/08/2011] [Accepted: 11/11/2011] [Indexed: 11/20/2022]
Abstract
The fruit fly Drosophila larva demonstrates a sophisticated repertoire of behavior under the control of a numerically simple neural system. Historically, the stereotyped responses of larvae to light and odors captivated the attention of biologists. More recently, the sensory receptors responsible for chemosensation, thermosensation, and vision have been identified. While our understanding of the molecular logic of perception has clearly progressed, little is known about the neural and computational mechanisms guiding movement in sensory gradients. Here we review evidence that larvae orient based on active sensation-a feature distinct from the strategies used by simpler model organisms. Reorientation maneuvers are controlled by the spatiotemporal integration of changes in stimulus intensity detected during runs and lateral head movements.
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Iyengar BG, Chou CJ, Vandamme KM, Klose MK, Zhao X, Akhtar-Danesh N, Campos AR, Atwood HL. Silencing synaptic communication between random interneurons duringDrosophilalarval locomotion. GENES BRAIN AND BEHAVIOR 2011; 10:883-900. [DOI: 10.1111/j.1601-183x.2011.00729.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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12
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Friedrich M. Drosophila as a developmental paradigm of regressive brain evolution: proof of principle in the visual system. BRAIN, BEHAVIOR AND EVOLUTION 2011; 78:199-215. [PMID: 21893944 DOI: 10.1159/000329850] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2011] [Accepted: 05/23/2011] [Indexed: 11/19/2022]
Abstract
Evolutionary developmental biology focuses heavily on the constructive evolution of body plan components, but there are many instances such as parasitism, cave adaptation, or postembryonic growth rate optimization where evolutionary regression is of adaptive value. This is particularly true in the nervous system because of its massive energy costs. However, comparatively little effort has thus far been made to understand the evolutionary developmental trajectories of adaptive nervous system reduction. This review focuses on the organization and evolution of the Drosophila larval brain, which represents an exceptional example of miniaturization, most dramatically in the visual system. It is specifically discussed how the dependency of outer optic lobe development on retinal innervation can be assumed to have facilitated a first evolutionary phase of larval visual system reduction. Afferent input-contingent development of neu- ral compartments very likely plays a widespread role in adaptive brain evolution. Understanding the complete deconstruction of the larval optic neuropiles in Drosophila awaits expanded comparative analysis but has the promise to inform about further developmental trajectories and mechanisms underlying regressive evolution of the brain.
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Affiliation(s)
- Markus Friedrich
- Department of Biological Sciences, School of Medicine, Wayne State University, Detroit, MI 48202, USA. friedrichm @ wayne.edu
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Khurana S, Robinson BG, Wang Z, Shropshire WC, Zhong AC, Garcia LE, Corpuz J, Chow J, Hatch MM, Precise EF, Cady A, Godinez RM, Pulpanyawong T, Nguyen AT, Li WK, Seiter M, Jahanian K, Sun JC, Shah R, Rajani S, Chen WY, Ray S, Ryazanova NV, Wakou D, Prabhu RK, Atkinson NS. Olfactory conditioning in the third instar larvae of Drosophila melanogaster using heat shock reinforcement. Behav Genet 2011; 42:151-61. [PMID: 21833772 DOI: 10.1007/s10519-011-9487-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2010] [Accepted: 07/13/2011] [Indexed: 11/25/2022]
Abstract
Adult Drosophila melanogaster has long been a popular model for learning and memory studies. Now the larval stage of the fruit fly is also being used in an increasing number of classical conditioning studies. In this study, we employed heat shock as a novel negative reinforcement for larvae and obtained high learning scores following just one training trial. We demonstrated heat-shock conditioning in both reciprocal and non-reciprocal paradigms and observed that the time window of association for the odor and heat shock reinforcement is on the order of a few minutes. This is slightly wider than the time window for electroshock conditioning reported in previous studies, possibly due to lingering effects of the high temperature. To test the utility of this simplified assay for the identification of new mutations that disrupt learning, we examined flies carrying mutations in the dnc gene. While the sensitivity to heat shock, as tested by writhing, was similar for wild type and dnc homozygotes, dnc mutations strongly diminished learning. We confirmed that the learning defect in dnc flies was indeed due to mutation in the dnc gene using non-complementation analysis. Given that heat shock has not been employed as a reinforcement for larvae in the past, we explored learning as a function of heat shock intensity and found that optimal learning occurred around 41 °C, with higher and lower temperatures both resulting in lower learning scores. In summary, we have developed a very simple, robust paradigm of learning in fruit fly larvae using heat shock reinforcement.
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Affiliation(s)
- Sukant Khurana
- Section of Neurobiology and Institute for Neuroscience, University of Texas at Austin, Austin, TX, USA.
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Shinomiya K, Matsuda K, Oishi T, Otsuna H, Ito K. Flybrain neuron database: a comprehensive database system of the Drosophila brain neurons. J Comp Neurol 2011; 519:807-33. [PMID: 21280038 DOI: 10.1002/cne.22540] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The long history of neuroscience has accumulated information about numerous types of neurons in the brain of various organisms. Because such neurons have been reported in diverse publications without controlled format, it is not easy to keep track of all the known neurons in a particular nervous system. To address this issue we constructed an online database called Flybrain Neuron Database (Flybrain NDB), which serves as a platform to collect and provide information about all the types of neurons published so far in the brain of Drosophila melanogaster. Projection patterns of the identified neurons in diverse areas of the brain were recorded in a unified format, with text-based descriptions as well as images and movies wherever possible. In some cases projection sites and the distribution of the post- and presynaptic sites were determined with greater detail than described in the original publication. Information about the labeling patterns of various antibodies and expression driver strains to visualize identified neurons are provided as a separate sub-database. We also implemented a novel visualization tool with which users can interactively examine three-dimensional reconstruction of the confocal serial section images with desired viewing angles and cross sections. Comprehensive collection and versatile search function of the anatomical information reported in diverse publications make it possible to analyze possible connectivity between different brain regions. We analyzed the preferential connectivity among optic lobe layers and the plausible olfactory sensory map in the lateral horn to show the usefulness of such a database.
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Affiliation(s)
- Kazunori Shinomiya
- Institute of Molecular and Cellular Biosciences, University of Tokyo, Tokyo, Japan
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Drosophila larvae establish appetitive olfactory memories via mushroom body neurons of embryonic origin. J Neurosci 2010; 30:10655-66. [PMID: 20702697 DOI: 10.1523/jneurosci.1281-10.2010] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Insect mushroom bodies are required for diverse behavioral functions, including odor learning and memory. Using the numerically simple olfactory pathway of the Drosophila melanogaster larva, we provide evidence that the formation of appetitive olfactory associations relies on embryonic-born intrinsic mushroom body neurons (Kenyon cells). The participation of larval-born Kenyon cells, i.e., neurons that become gradually integrated in the developing mushroom body during larval life, in this task is unlikely. These data provide important insights into how a small set of identified Kenyon cells can store and integrate olfactory information in a developing brain. To investigate possible functional subdivisions of the larval mushroom body, we anatomically disentangle its input and output neurons at the single-cell level. Based on this approach, we define 10 subdomains of the larval mushroom body that may be implicated in mediating specific interactions between the olfactory pathway, modulatory neurons, and neuronal output.
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Løfaldli BB, Kvello P, Mustaparta H. Integration of the antennal lobe glomeruli and three projection neurons in the standard brain atlas of the moth heliothis virescens. Front Syst Neurosci 2010; 4:5. [PMID: 20179785 PMCID: PMC2826183 DOI: 10.3389/neuro.06.005.2010] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2009] [Accepted: 01/26/2010] [Indexed: 11/13/2022] Open
Abstract
Digital three dimensional standard brain atlases (SBAs) are valuable tools for integrating neuroimaging data of different preparations. In insects, SBAs of five species are available, including the atlas of the female Heliothis virescens moth brain. Like for the other species, the antennal lobes (ALs) of the moth brain atlas were integrated as one material identity without internal structures. Different from the others, the H. virescens SBA exclusively included the glomerular layer of the AL. This was an advantage in the present study for performing a direct registration of the glomerular layer of individual preparations into the standard brain. We here present the H. virescens female SBA with a new model of the AL glomeruli integrated into the atlas, i.e. with each of the 66 glomeruli identified and labelled with a specific number. The new model differs from the previous H. virescens AL model both in respect to the number of glomeruli and the numbering system; the latter according to the system used for the AL atlases of two other heliothine species. For identifying female specific glomeruli comparison with the male AL was necessary. This required a new male AL atlas, included in this paper. As demonstrated by the integration of three AL projection neurons of different preparations, the new SBA with the integrated glomruli is a helpful tool for determining the glomeruli innervated as well as the relative position of the axonal projections in the protocerebrum.
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Affiliation(s)
- Bjarte Bye Løfaldli
- Neuroscience Unit, Department of Biology, Norwegian University of Science and Technology Trondheim, Norway
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Jansen AM, Nässel DR, Madsen KL, Jung AG, Gether U, Kjaerulff O. PICK1 expression in theDrosophilacentral nervous system primarily occurs in the neuroendocrine system. J Comp Neurol 2009; 517:313-32. [DOI: 10.1002/cne.22155] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Kvello P, Løfaldli BB, Rybak J, Menzel R, Mustaparta H. Digital, Three-dimensional Average Shaped Atlas of the Heliothis Virescens Brain with Integrated Gustatory and Olfactory Neurons. Front Syst Neurosci 2009; 3:14. [PMID: 19949481 PMCID: PMC2784302 DOI: 10.3389/neuro.06.014.2009] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2009] [Accepted: 10/02/2009] [Indexed: 12/02/2022] Open
Abstract
We use the moth Heliothis virescens as model organism for studying the neural network involved in chemosensory coding and learning. The constituent neurons are characterised by intracellular recordings combined with staining, resulting in a single neuron identified in each brain preparation. In order to spatially relate the neurons of different preparations a common brain framework was required. We here present an average shaped atlas of the moth brain. It is based on 11 female brain preparations, each stained with a fluorescent synaptic marker and scanned in confocal laser-scanning microscope. Brain neuropils of each preparation were manually reconstructed in the computer software Amira, followed by generating the atlas using the Iterative Shape Average Procedure. To demonstrate the application of the atlas we have registered two olfactory and two gustatory interneurons, as well as the axonal projections of gustatory receptor neurons into the atlas, visualising their spatial relationships. The olfactory interneurons, showing the typical morphology of inner-tract antennal lobe projection neurons, projected in the calyces of the mushroom body and laterally in the protocerebral lobe. The two gustatory interneurons, responding to sucrose and quinine respectively, projected in different areas of the brain. The wide projections of the quinine responding neuron included a lateral area adjacent to the projections of the olfactory interneurons. The sucrose responding neuron was confined to the suboesophageal ganglion with dendritic arborisations overlapping the axonal projections of the gustatory receptor neurons on the proboscis. By serving as a tool for the integration of neurons, the atlas offers visual access to the spatial relationship between the neurons in three dimensions, and thus facilitates the study of neuronal networks in the Heliothis virescens brain. The moth standard brain is accessible at http://www.ntnu.no/biolog/english/neuroscience/brain
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Affiliation(s)
- Pål Kvello
- Department of Biology, Norwegian University of Science and Technology Trondheim, Norway
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Selcho M, Pauls D, Han KA, Stocker RF, Thum AS. The role of dopamine in Drosophila larval classical olfactory conditioning. PLoS One 2009; 4:e5897. [PMID: 19521527 PMCID: PMC2690826 DOI: 10.1371/journal.pone.0005897] [Citation(s) in RCA: 134] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2009] [Accepted: 05/07/2009] [Indexed: 11/18/2022] Open
Abstract
Learning and memory is not an attribute of higher animals. Even Drosophila larvae are able to form and recall an association of a given odor with an aversive or appetitive gustatory reinforcer. As the Drosophila larva has turned into a particularly simple model for studying odor processing, a detailed neuronal and functional map of the olfactory pathway is available up to the third order neurons in the mushroom bodies. At this point, a convergence of olfactory processing and gustatory reinforcement is suggested to underlie associative memory formation. The dopaminergic system was shown to be involved in mammalian and insect olfactory conditioning. To analyze the anatomy and function of the larval dopaminergic system, we first characterize dopaminergic neurons immunohistochemically up to the single cell level and subsequent test for the effects of distortions in the dopamine system upon aversive (odor-salt) as well as appetitive (odor-sugar) associative learning. Single cell analysis suggests that dopaminergic neurons do not directly connect gustatory input in the larval suboesophageal ganglion to olfactory information in the mushroom bodies. However, a number of dopaminergic neurons innervate different regions of the brain, including protocerebra, mushroom bodies and suboesophageal ganglion. We found that dopamine receptors are highly enriched in the mushroom bodies and that aversive and appetitive olfactory learning is strongly impaired in dopamine receptor mutants. Genetically interfering with dopaminergic signaling supports this finding, although our data do not exclude on naïve odor and sugar preferences of the larvae. Our data suggest that dopaminergic neurons provide input to different brain regions including protocerebra, suboesophageal ganglion and mushroom bodies by more than one route. We therefore propose that different types of dopaminergic neurons might be involved in different types of signaling necessary for aversive and appetitive olfactory memory formation respectively, or for the retrieval of these memory traces. Future studies of the dopaminergic system need to take into account such cellular dissociations in function in order to be meaningful.
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Affiliation(s)
- Mareike Selcho
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Dennis Pauls
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Kyung-An Han
- Department of Biology and The Huck Institute Neuroscience and Genetics Graduate Program, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | | | - Andreas S. Thum
- Department of Biology, University of Fribourg, Fribourg, Switzerland
- * E-mail:
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Kurylas AE, Rohlfing T, Krofczik S, Jenett A, Homberg U. Standardized atlas of the brain of the desert locust, Schistocerca gregaria. Cell Tissue Res 2008; 333:125-45. [DOI: 10.1007/s00441-008-0620-x] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2008] [Accepted: 03/31/2008] [Indexed: 11/29/2022]
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Daniels RW, Gelfand MV, Collins CA, DiAntonio A. Visualizing glutamatergic cell bodies and synapses in Drosophila larval and adult CNS. J Comp Neurol 2008; 508:131-52. [PMID: 18302156 DOI: 10.1002/cne.21670] [Citation(s) in RCA: 142] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Glutamate is the major excitatory neurotransmitter in the vertebrate central nervous system (CNS) and at Drosophila neuromuscular junctions (NMJs). Although glutamate is also used as a transmitter in the Drosophila CNS, there has been no systematic description of the central glutamatergic signaling system in the fly. With the recent cloning of the Drosophila vesicular glutamate transporter (DVGLUT), it is now possible to mark many, if not all, central glutamatergic neurons and synapses. Here we present the pattern of glutamatergic synapses and cell bodies in the late larval CNS and in the adult fly brain by using an anti-DVGLUT antibody. We also introduce two new tools for studying the Drosophila glutamatergic system: a dvglut promoter fragment fused to Gal4 whose expression labels glutamatergic neurons and a green fluorescent protein (GFP)-tagged DVGLUT transgene that localizes to synapses. In the larval CNS, we find synaptic DVGLUT immunoreactivity prominent in all brain lobe neuropil compartments except for the mushroom body. Likewise in the adult CNS, glutamatergic synapses are abundant throughout all major brain structures except the mushroom body. We also find that the larval ventral nerve cord neuropil is rich in glutamatergic synapses, which are primarily located near the dorsal surface of the neuropil, segregated from the ventrally positioned cholinergic processes. This description of the glutamatergic system in Drosophila highlights the prevalence of glutamatergic neurons in the CNS and presents tools for future study and manipulation of glutamatergic transmission.
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Affiliation(s)
- Richard W Daniels
- Department of Molecular Biology and Pharmacology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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Abstract
Glutamate is the predominant excitatory neurotransmitter in the vertebrate brain, whereas acetylcholine has been considered to play the same role in insects. Recent studies have, however, questioned the latter view by showing a rather general distribution of glutamate transporters. Here, we describe the expression pattern of the receptor DmGlu-A (DmGluRA), the unique homolog of vertebrate metabotropic glutamate receptors. Metabotropic glutamate receptors play important roles in the regulation of glutamatergic neurotransmission. Using a specific antibody, we report DmGluRA expression in most neuropile areas in both larvae and adults, but not in the lobes of the mushroom bodies. These observations suggest a key role for glutamate in the insect brain.
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Neuroarchitecture of aminergic systems in the larval ventral ganglion of Drosophila melanogaster. PLoS One 2008; 3:e1848. [PMID: 18365004 PMCID: PMC2268740 DOI: 10.1371/journal.pone.0001848] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2007] [Accepted: 02/12/2008] [Indexed: 12/24/2022] Open
Abstract
Biogenic amines are important signaling molecules in the central nervous system of both vertebrates and invertebrates. In the fruit fly Drosophila melanogaster, biogenic amines take part in the regulation of various vital physiological processes such as feeding, learning/memory, locomotion, sexual behavior, and sleep/arousal. Consequently, several morphological studies have analyzed the distribution of aminergic neurons in the CNS. Previous descriptions, however, did not determine the exact spatial location of aminergic neurite arborizations within the neuropil. The release sites and pre-/postsynaptic compartments of aminergic neurons also remained largely unidentified. We here used gal4-driven marker gene expression and immunocytochemistry to map presumed serotonergic (5-HT), dopaminergic, and tyraminergic/octopaminergic neurons in the thoracic and abdominal neuromeres of the Drosophila larval ventral ganglion relying on Fasciclin2-immunoreactive tracts as three-dimensional landmarks. With tyrosine hydroxylase- (TH) or tyrosine decarboxylase 2 (TDC2)-specific gal4-drivers, we also analyzed the distribution of ectopically expressed neuronal compartment markers in presumptive dopaminergic TH and tyraminergic/octopaminergic TDC2 neurons, respectively. Our results suggest that thoracic and abdominal 5-HT and TH neurons are exclusively interneurons whereas most TDC2 neurons are efferent. 5-HT and TH neurons are ideally positioned to integrate sensory information and to modulate neuronal transmission within the ventral ganglion, while most TDC2 neurons appear to act peripherally. In contrast to 5-HT neurons, TH and TDC2 neurons each comprise morphologically different neuron subsets with separated in- and output compartments in specific neuropil regions. The three-dimensional mapping of aminergic neurons now facilitates the identification of neuronal network contacts and co-localized signaling molecules, as exemplified for DOPA decarboxylase-synthesizing neurons that co-express crustacean cardioactive peptide and myoinhibiting peptides.
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