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Shahzad MF, Xu S, Naveed W, Nusrat S, Zahid I. Investigating the impact of artificial intelligence on human resource functions in the health sector of China: A mediated moderation model. Heliyon 2023; 9:e21818. [PMID: 38034787 PMCID: PMC10685199 DOI: 10.1016/j.heliyon.2023.e21818] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2023] [Revised: 10/25/2023] [Accepted: 10/30/2023] [Indexed: 12/02/2023] Open
Abstract
Artificial intelligence (AI) is rapidly transforming the way human resources (HR) functions are carried out in the health sector of China. This study aims to scrutinize the impact of artificial intelligence on the human resource functions operating in the healthcare sector through technological awareness, social media influence, and personal innovativeness. Additionally, this study examines the moderating role of perceived risk between technological awareness and human resources functions. An online questionnaire was administered to human resources professionals in the health sector of China to gather data from 363 respondents. Partial least squares structural equation modeling (PLS-SEM), a statistical procedure, is implemented to investigate the hypothesis of the projected model of artificial intelligence and human resource functions. The research findings reveal that artificial intelligence significantly influences human resource functions through technological awareness, social media influence, and personal innovativeness. Furthermore, perceived risk significantly moderates the relationship between technological awareness and human resource functions. The findings of this study have important implications for HR practitioners and policymakers in the health sectors of China, who can leverage artificial intelligence technologies to optimize and improve organizational performance. However, its adoption needs to be carefully planned and managed to reap the full benefits of this transformative technology.
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Affiliation(s)
| | - Shuo Xu
- College of Economics and Management, Beijing University of Technology, Beijing 100124, PR China
| | - Waliha Naveed
- Institute of Business & Management, University of Engineering and Technology, Lahore 54000, Pakistan
| | - Shahneela Nusrat
- College of Environment and Life Science, Beijing University of Technology, Beijing 100124, PR China
| | - Imran Zahid
- Department of Mechanical Engineering and Technology, Government College University Faisalabad, Pakistan
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2
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Motion vision: Drosophila neural pathways that go with the visual flow. Curr Biol 2022; 32:R881-R883. [PMID: 35998597 DOI: 10.1016/j.cub.2022.07.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Processing visual motion cues to interpret self-motion, the movement of others, and the environment's structure is vital to all animals, whether prey or predator. A new study in Drosophila identifies multiple pathways likely contributing to visual motion-dependent computations and behaviors.
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3
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Bates AS, Jefferis G. Systems neuroscience: Auditory processing at synaptic resolution. Curr Biol 2022; 32:R830-R833. [PMID: 35944481 DOI: 10.1016/j.cub.2022.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Deeper layers of the auditory system have not been fully mapped in any model system. A new study links comprehensive connectomics of Drosophila song perception circuits to physiological response profiles.
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Affiliation(s)
- Alexander Shakeel Bates
- Department of Neurobiology and Howard Hughes Medical Institute, Harvard Medical School, Boston, MA, USA
| | - Greg Jefferis
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK; Drosophila Connectomics Group, Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK.
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4
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Chen PJ, Li Y, Lee CH. Calcium Imaging of Neural Activity in Fly Photoreceptors. Cold Spring Harb Protoc 2022; 2022:Pdb.top107800. [PMID: 35641092 DOI: 10.1101/pdb.top107800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Functional imaging methodologies allow researchers to simultaneously monitor the neural activities of all single neurons in a population, and this ability has led to great advances in neuroscience research. Taking advantage of a genetically tractable model organism, functional imaging in Drosophila provides opportunities to probe scientific questions that were previously unanswerable by electrophysiological recordings. Here, we introduce comprehensive protocols for two-photon calcium imaging in fly visual neurons. We also discuss some challenges in applying optical imaging techniques to study visual systems and consider the best practices for making comparisons between different neuron groups.
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Affiliation(s)
- Pei-Ju Chen
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 11529, Taiwan, Republic of China
| | - Yan Li
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 11529, Taiwan, Republic of China
| | - Chi-Hon Lee
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 11529, Taiwan, Republic of China
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5
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Zeltser G, Sukhanov IM, Nevorotin AJ. MMM - The molecular model of memory. J Theor Biol 2022; 549:111219. [PMID: 35810778 DOI: 10.1016/j.jtbi.2022.111219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Revised: 07/01/2022] [Accepted: 07/04/2022] [Indexed: 11/17/2022]
Abstract
Identifying mechanisms underlying neurons ability to process information including acquisition, storage, and retrieval plays an important role in the understanding of the different types of memory, pathogenesis of many neurological diseases affecting memory and therapeutic target discovery. However, the traditional understanding of the mechanisms of memory associated with the electrical signals having a unique combination of frequency and amplitude does not answer the question how the memories can survive for life-long periods of time, while exposed to synaptic noise. Recent evidence suggests that, apart from neuronal circuits, a diversity of the molecular memory (MM) carriers, are essential for memory performance. The molecular model of memory (MMM) is proposed, according to which each item of incoming information (the elementary memory item - eMI) is encoded by both circuitries, with the unique for a given MI electrical parameters, and also the MM carriers, unique by its molecular composition. While operating as the carriers of incoming information, the MMs, are functioning within the neuron plasma membrane. Inactive (latent) initially, during acquisition each of the eMIs is activated to become a virtual copy of some real fact or events bygone. This activation is accompanied by the considerable remodeling of the MM molecule associated with the resonance effect.
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Affiliation(s)
| | - Ilya M Sukhanov
- Lab. Behavioral Pharmacology, Dept. Psychopharmacology, Valdman Institute of Pharmacology, I.P. Pavlov Medical University, Leo Tolstoi Street 6/8, St. Petersburg 197022, The Russian Federation
| | - Alexey J Nevorotin
- Laboratory of Electron Microscopy, I.P. Pavlov Medical University, Leo Tolstoi Street 6/8, St. Petersburg 197022, The Russian Federation
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6
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Adel M, Chen N, Zhang Y, Reed ML, Quasney C, Griffith LC. Pairing-Dependent Plasticity in a Dissected Fly Brain Is Input-Specific and Requires Synaptic CaMKII Enrichment and Nighttime Sleep. J Neurosci 2022; 42:4297-4310. [PMID: 35474278 PMCID: PMC9145224 DOI: 10.1523/jneurosci.0144-22.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 03/23/2022] [Accepted: 04/19/2022] [Indexed: 11/21/2022] Open
Abstract
In Drosophila, in vivo functional imaging studies revealed that associative memory formation is coupled to a cascade of neural plasticity events in distinct compartments of the mushroom body (MB). In-depth investigation of the circuit dynamics, however, will require an ex vivo model that faithfully mirrors these events to allow direct manipulations of circuit elements that are inaccessible in the intact fly. The current ex vivo models have been able to reproduce the fundamental plasticity of aversive short-term memory, a potentiation of the MB intrinsic neuron (Kenyon cells [KCs]) responses after artificial learning ex vivo However, this potentiation showed different localization and encoding properties from those reported in vivo and failed to generate the previously reported suppression plasticity in the MB output neurons (MBONs). Here, we develop an ex vivo model using the female Drosophila brain that recapitulates behaviorally evoked plasticity in the KCs and MBONs. We demonstrate that this plasticity accurately localizes to the MB α'3 compartment and is encoded by a coincidence between KC activation and dopaminergic input. The formed plasticity is input-specific, requiring pairing of the conditioned stimulus and unconditioned stimulus pathways; hence, we name it pairing-dependent plasticity. Pairing-dependent plasticity formation requires an intact CaMKII gene and is blocked by previous-night sleep deprivation but is rescued by rebound sleep. In conclusion, we show that our ex vivo preparation recapitulates behavioral and imaging results from intact animals and can provide new insights into mechanisms of memory formation at the level of molecules, circuits, and brain state.SIGNIFICANCE STATEMENT The mammalian ex vivo LTP model enabled in-depth investigation of the hippocampal memory circuit. We develop a parallel model to study the Drosophila mushroom body (MB) memory circuit. Pairing activation of the conditioned stimulus and unconditioned stimulus pathways in dissected brains induces a potentiation pairing-dependent plasticity (PDP) in the axons of α'β' Kenyon cells and a suppression PDP in the dendrites of their postsynaptic MB output neurons, localized in the MB α'3 compartment. This PDP is input-specific and requires the 3' untranslated region of CaMKII Interestingly, ex vivo PDP carries information about the animal's experience before dissection; brains from sleep-deprived animals fail to form PDP, whereas those from animals who recovered 2 h of their lost sleep form PDP.
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Affiliation(s)
- Mohamed Adel
- Department of Biology and Volen National Center for Complex Systems, Brandeis University, Waltham, Massachusetts 02454-9110
| | - Nannan Chen
- Department of Biology and Volen National Center for Complex Systems, Brandeis University, Waltham, Massachusetts 02454-9110
| | - Yunpeng Zhang
- Department of Biology and Volen National Center for Complex Systems, Brandeis University, Waltham, Massachusetts 02454-9110
| | - Martha L Reed
- Department of Biology and Volen National Center for Complex Systems, Brandeis University, Waltham, Massachusetts 02454-9110
| | - Christina Quasney
- Department of Biology and Volen National Center for Complex Systems, Brandeis University, Waltham, Massachusetts 02454-9110
| | - Leslie C Griffith
- Department of Biology and Volen National Center for Complex Systems, Brandeis University, Waltham, Massachusetts 02454-9110
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7
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Zjacic N, Scholz M. The role of food odor in invertebrate foraging. GENES, BRAIN, AND BEHAVIOR 2022; 21:e12793. [PMID: 34978135 PMCID: PMC9744530 DOI: 10.1111/gbb.12793] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 12/01/2021] [Accepted: 12/18/2021] [Indexed: 11/30/2022]
Abstract
Foraging for food is an integral part of animal survival. In small insects and invertebrates, multisensory information and optimized locomotion strategies are used to effectively forage in patchy and complex environments. Here, the importance of olfactory cues for effective invertebrate foraging is discussed in detail. We review how odors are used by foragers to move toward a likely food source and the recent models that describe this sensory-driven behavior. We argue that smell serves a second function by priming an organism for the efficient exploitation of food. By appraising food odors, invertebrates can establish preferences and better adapt to their ecological niches, thereby promoting survival. The smell of food pre-prepares the gastrointestinal system and primes feeding motor programs for more effective ingestion as well. Optimizing resource utilization affects longevity and reproduction as a result, leading to drastic changes in survival. We propose that models of foraging behavior should include odor priming, and illustrate this with a simple toy model based on the marginal value theorem. Lastly, we discuss the novel techniques and assays in invertebrate research that could investigate the interactions between odor sensing and food intake. Overall, the sense of smell is indispensable for efficient foraging and influences not only locomotion, but also organismal physiology, which should be reflected in behavioral modeling.
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Affiliation(s)
- Nicolina Zjacic
- Max Planck Research Group Neural Information FlowCenter of Advanced European Studies and Research (Caesar)BonnGermany
| | - Monika Scholz
- Max Planck Research Group Neural Information FlowCenter of Advanced European Studies and Research (Caesar)BonnGermany
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8
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Aymanns F, Chen CL, Ramdya P. Descending neuron population dynamics during odor-evoked and spontaneous limb-dependent behaviors. eLife 2022; 11:81527. [PMID: 36286408 PMCID: PMC9605690 DOI: 10.7554/elife.81527] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 10/13/2022] [Indexed: 11/21/2022] Open
Abstract
Deciphering how the brain regulates motor circuits to control complex behaviors is an important, long-standing challenge in neuroscience. In the fly, Drosophila melanogaster, this is coordinated by a population of ~ 1100 descending neurons (DNs). Activating only a few DNs is known to be sufficient to drive complex behaviors like walking and grooming. However, what additional role the larger population of DNs plays during natural behaviors remains largely unknown. For example, they may modulate core behavioral commands or comprise parallel pathways that are engaged depending on sensory context. We evaluated these possibilities by recording populations of nearly 100 DNs in individual tethered flies while they generated limb-dependent behaviors, including walking and grooming. We found that the largest fraction of recorded DNs encode walking while fewer are active during head grooming and resting. A large fraction of walk-encoding DNs encode turning and far fewer weakly encode speed. Although odor context does not determine which behavior-encoding DNs are recruited, a few DNs encode odors rather than behaviors. Lastly, we illustrate how one can identify individual neurons from DN population recordings by using their spatial, functional, and morphological properties. These results set the stage for a comprehensive, population-level understanding of how the brain’s descending signals regulate complex motor actions.
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Affiliation(s)
- Florian Aymanns
- Neuroengineering Laboratory, Brain Mind Institute & Interfaculty Institute of Bioengineering, EPFLLausanneSwitzerland
| | - Chin-Lin Chen
- Neuroengineering Laboratory, Brain Mind Institute & Interfaculty Institute of Bioengineering, EPFLLausanneSwitzerland
| | - Pavan Ramdya
- Neuroengineering Laboratory, Brain Mind Institute & Interfaculty Institute of Bioengineering, EPFLLausanneSwitzerland
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9
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Schlegel P, Bates AS, Stürner T, Jagannathan SR, Drummond N, Hsu J, Serratosa Capdevila L, Javier A, Marin EC, Barth-Maron A, Tamimi IFM, Li F, Rubin GM, Plaza SM, Costa M, Jefferis GSXE. Information flow, cell types and stereotypy in a full olfactory connectome. eLife 2021; 10:e66018. [PMID: 34032214 PMCID: PMC8298098 DOI: 10.7554/elife.66018] [Citation(s) in RCA: 60] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 05/24/2021] [Indexed: 12/19/2022] Open
Abstract
The hemibrain connectome provides large-scale connectivity and morphology information for the majority of the central brain of Drosophila melanogaster. Using this data set, we provide a complete description of the Drosophila olfactory system, covering all first, second and lateral horn-associated third-order neurons. We develop a generally applicable strategy to extract information flow and layered organisation from connectome graphs, mapping olfactory input to descending interneurons. This identifies a range of motifs including highly lateralised circuits in the antennal lobe and patterns of convergence downstream of the mushroom body and lateral horn. Leveraging a second data set we provide a first quantitative assessment of inter- versus intra-individual stereotypy. Comparing neurons across two brains (three hemispheres) reveals striking similarity in neuronal morphology across brains. Connectivity correlates with morphology and neurons of the same morphological type show similar connection variability within the same brain as across two brains.
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Affiliation(s)
- Philipp Schlegel
- Neurobiology Division, MRC Laboratory of Molecular BiologyCambridgeUnited Kingdom
- Department of Zoology, University of CambridgeCambridgeUnited Kingdom
| | | | - Tomke Stürner
- Department of Zoology, University of CambridgeCambridgeUnited Kingdom
| | | | - Nikolas Drummond
- Department of Zoology, University of CambridgeCambridgeUnited Kingdom
| | - Joseph Hsu
- Department of Zoology, University of CambridgeCambridgeUnited Kingdom
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | | | - Alexandre Javier
- Department of Zoology, University of CambridgeCambridgeUnited Kingdom
| | - Elizabeth C Marin
- Department of Zoology, University of CambridgeCambridgeUnited Kingdom
| | - Asa Barth-Maron
- Department of Neurobiology, Harvard Medical SchoolBostonUnited States
| | - Imaan FM Tamimi
- Department of Zoology, University of CambridgeCambridgeUnited Kingdom
| | - Feng Li
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Gerald M Rubin
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Stephen M Plaza
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Marta Costa
- Department of Zoology, University of CambridgeCambridgeUnited Kingdom
| | - Gregory S X E Jefferis
- Neurobiology Division, MRC Laboratory of Molecular BiologyCambridgeUnited Kingdom
- Department of Zoology, University of CambridgeCambridgeUnited Kingdom
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10
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Link N, Bellen HJ. Using Drosophila to drive the diagnosis and understand the mechanisms of rare human diseases. Development 2020; 147:dev191411. [PMID: 32988995 PMCID: PMC7541339 DOI: 10.1242/dev.191411] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Next-generation sequencing has greatly accelerated the discovery of rare human genetic diseases. Nearly 45% of patients have variants associated with known diseases but the unsolved cases remain a conundrum. Moreover, causative mutations can be difficult to pinpoint because variants frequently map to genes with no previous disease associations and, often, only one or a few patients with variants in the same gene are identified. Model organisms, such as Drosophila, can help to identify and characterize these new disease-causing genes. Importantly, Drosophila allow quick and sophisticated genetic manipulations, permit functional testing of human variants, enable the characterization of pathogenic mechanisms and are amenable to drug tests. In this Spotlight, focusing on microcephaly as a case study, we highlight how studies of human genes in Drosophila have aided our understanding of human genetic disorders, allowing the identification of new genes in well-established signaling pathways.
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Affiliation(s)
- Nichole Link
- Howard Hughes Medical Institute, BCM, Houston, TX, 77030, USA
- Department of Molecular and Human Genetics (MHG), BCM, Houston, TX, 77030, USA
- Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, 77030, USA
| | - Hugo J Bellen
- Howard Hughes Medical Institute, BCM, Houston, TX, 77030, USA
- Department of Molecular and Human Genetics (MHG), BCM, Houston, TX, 77030, USA
- Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, 77030, USA
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11
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Tadres D, Louis M. PiVR: An affordable and versatile closed-loop platform to study unrestrained sensorimotor behavior. PLoS Biol 2020; 18:e3000712. [PMID: 32663220 PMCID: PMC7360024 DOI: 10.1371/journal.pbio.3000712] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 06/09/2020] [Indexed: 12/19/2022] Open
Abstract
Tools enabling closed-loop experiments are crucial to delineate causal relationships between the activity of genetically labeled neurons and specific behaviors. We developed the Raspberry Pi Virtual Reality (PiVR) system to conduct closed-loop optogenetic stimulation of neural functions in unrestrained animals. PiVR is an experimental platform that operates at high temporal resolution (70 Hz) with low latencies (<30 milliseconds), while being affordable (
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Affiliation(s)
- David Tadres
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, Santa Barbara, California, United States of America
- Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, California, United States of America
- Institute of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | - Matthieu Louis
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, Santa Barbara, California, United States of America
- Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, California, United States of America
- Department of Physics, University of California, Santa Barbara, Santa Barbara, California, United States of America
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12
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Huang C, Tai CY, Yang KP, Chang WK, Hsu KJ, Hsiao CC, Wu SC, Lin YY, Chiang AS, Chu SW. All-Optical Volumetric Physiology for Connectomics in Dense Neuronal Structures. iScience 2019; 22:133-146. [PMID: 31765994 PMCID: PMC6883334 DOI: 10.1016/j.isci.2019.11.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 09/19/2019] [Accepted: 11/04/2019] [Indexed: 01/04/2023] Open
Abstract
All-optical physiology (AOP) manipulates and reports neuronal activities with light, allowing for interrogation of neuronal functional connections with high spatiotemporal resolution. However, contemporary high-speed AOP platforms are limited to single-depth or discrete multi-plane recordings that are not suitable for studying functional connections among densely packed small neurons, such as neurons in Drosophila brains. Here, we constructed a 3D AOP platform by incorporating single-photon point stimulation and two-photon high-speed volumetric recordings with a tunable acoustic gradient-index (TAG) lens. We demonstrated the platform effectiveness by studying the anterior visual pathway (AVP) of Drosophila. We achieved functional observation of spatiotemporal coding and the strengths of calcium-sensitive connections between anterior optic tubercle (AOTU) sub-compartments and >70 tightly assembled 2-μm bulb (BU) microglomeruli in 3D coordinates with a single trial. Our work aids the establishment of in vivo 3D functional connectomes in neuron-dense brain areas. All-optical volumetric physiology = precise stimulation + fast volumetric recording Precise single-photon point stimulation among genetically defined neurons 3D two-photon imaging by an acoustic gradient-index lens for dense neural structures Observation of 3D functional connectivity in Drosophila anterior visual pathway
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Affiliation(s)
- Chiao Huang
- Department of Physics, National Taiwan University, 1, Sec 4, Roosevelt Road, Taipei 10617, Taiwan
| | - Chu-Yi Tai
- Institute of Biotechnology, National Tsing Hua University, 101, Sec 2, Guangfu Road, Hsinchu 30013, Taiwan
| | - Kai-Ping Yang
- Department of Physics, National Taiwan University, 1, Sec 4, Roosevelt Road, Taipei 10617, Taiwan
| | - Wei-Kun Chang
- Brain Research Center, National Tsing Hua University, 101, Sec 2, Guangfu Road, Hsinchu 30013, Taiwan
| | - Kuo-Jen Hsu
- Department of Physics, National Taiwan University, 1, Sec 4, Roosevelt Road, Taipei 10617, Taiwan; Brain Research Center, National Tsing Hua University, 101, Sec 2, Guangfu Road, Hsinchu 30013, Taiwan
| | - Ching-Chun Hsiao
- Department of Engineering and System Science, National Tsing Hua University, 101, Sec 2, Guangfu Road, Hsinchu 30013, Taiwan
| | - Shun-Chi Wu
- Department of Engineering and System Science, National Tsing Hua University, 101, Sec 2, Guangfu Road, Hsinchu 30013, Taiwan
| | - Yen-Yin Lin
- Brain Research Center, National Tsing Hua University, 101, Sec 2, Guangfu Road, Hsinchu 30013, Taiwan.
| | - Ann-Shyn Chiang
- Institute of Biotechnology, National Tsing Hua University, 101, Sec 2, Guangfu Road, Hsinchu 30013, Taiwan; Brain Research Center, National Tsing Hua University, 101, Sec 2, Guangfu Road, Hsinchu 30013, Taiwan; Institute of Systems Neuroscience, National Tsing Hua University, 101, Sec 2, Guangfu Road, Hsinchu 30013, Taiwan; Department of Biomedical Science and Environmental Biology, Kaohsiung Medical University, Kaohsiung 80780, Taiwan; Graduate Institute of Clinical Medical Science, China Medical University, Taichung 40402, Taiwan; Institute of Molecular and Genomic Medicine, National Health Research Institutes, Zhunan, Miaoli 35053, Taiwan; Kavli Institute for Brain and Mind, University of California, San Diego, CA 92161, USA.
| | - Shi-Wei Chu
- Department of Physics, National Taiwan University, 1, Sec 4, Roosevelt Road, Taipei 10617, Taiwan; Molecular Imaging Center, National Taiwan University, 1, Sec 4, Roosevelt Road, Taipei 10617, Taiwan.
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13
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Sullivan LF. Rewiring the Drosophila Brain With Genetic Manipulations in Neural Lineages. Front Mol Neurosci 2019; 12:82. [PMID: 31019451 PMCID: PMC6458239 DOI: 10.3389/fnmol.2019.00082] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 03/14/2019] [Indexed: 11/13/2022] Open
Abstract
Neurons originate from neural stem cells and then synapse with stereotyped partners to form neuronal circuits. Recent findings indicate that several molecular mechanisms generating neuronal identity can rewire neuronal connectivity in the Drosophila brain when genetically manipulated. In this review, I discuss how mechanisms generating neuronal identity could activate molecular pathways essential for circuit formation and function. Next, I propose that the central complex of Drosophila, an ancient and highly conserved brain region essential for locomotor control and navigation, is an excellent model system to further explore mechanisms linking circuit development to circuit function.
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Affiliation(s)
- Luis F Sullivan
- Institute of Neuroscience, University of Oregon, Eugene, OR, United States
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14
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A Computational Model of the Escape Response Latency in the Giant Fiber System of Drosophila melanogaster. eNeuro 2019; 6:eN-NWR-0423-18. [PMID: 31001574 PMCID: PMC6469880 DOI: 10.1523/eneuro.0423-18.2019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 02/22/2019] [Accepted: 03/11/2019] [Indexed: 11/29/2022] Open
Abstract
The giant fiber system (GFS) is a multi-component neuronal pathway mediating rapid escape response in the adult fruit-fly Drosophila melanogaster, usually in the face of a threatening visual stimulus. Two branches of the circuit promote the response by stimulating an escape jump followed by flight initiation. A recent work demonstrated an age-associated decline in the speed of signal propagation through the circuit, measured as the stimulus-to-muscle depolarization response latency. The decline is likely due to the diminishing number of inter-neuronal gap junctions in the GFS of ageing flies. In this work, we presented a realistic conductance-based, computational model of the GFS that recapitulates the experimental results and identifies some of the critical anatomical and physiological components governing the circuit’s response latency. According to our model, anatomical properties of the GFS neurons have a stronger impact on the transmission than neuronal membrane conductance densities. The model provides testable predictions for the effect of experimental interventions on the circuit’s performance in young and ageing flies.
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15
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Two Drosophila Neuropeptide Y-like Neurons Define a Reward Module for Transforming Appetitive Odor Representations to Motivation. Sci Rep 2018; 8:11658. [PMID: 30076343 PMCID: PMC6076267 DOI: 10.1038/s41598-018-30113-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 07/24/2018] [Indexed: 01/15/2023] Open
Abstract
Neuropeptides, many of which are conserved among vertebrate and invertebrate animals, are implicated in the regulation of motivational states that selectively facilitate goal-directed behaviors. After a brief presentation of appetitive odors, Drosophila larvae display an impulsive-like feeding activity in readily accessible palatable food. This innate appetitive response may require coordinated signaling activities of dopamine (DA) and neuropeptide F (NPF; a fly homolog of neuropeptide Y). Here we provide anatomical and functional evidence, at single-cell resolution, that two NPF neurons define a reward module in the highest-order brain region for cognitive processing of food-related olfactory representations. First, laser lesioning of these NPF neurons abolished odor induction of appetitive arousal, while their genetic activation mimicked the behavioral effect of appetitive odors. Further, a circuit analysis shows that each of the two NPF neurons relays its signals to a subset of target neurons in the larval hindbrain-like region. Finally, the NPF neurons discriminatively responded to appetitive odor stimuli, and their odor responses were blocked by targeted lesioning of a pair of dopaminergic third-order olfactory neurons that appear to be presynaptic to the NPF neurons. Therefore, the two NPF neurons contribute to appetitive odor induction of impulsive-like feeding by selectively decoding DA-encoded ascending olfactory inputs and relaying NPF-encoded descending motivational outputs for behavioral execution.
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16
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Krzeptowski W, Hess G, Pyza E. Circadian Plasticity in the Brain of Insects and Rodents. Front Neural Circuits 2018; 12:32. [PMID: 29770112 PMCID: PMC5942159 DOI: 10.3389/fncir.2018.00032] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 04/09/2018] [Indexed: 12/22/2022] Open
Abstract
In both vertebrate and invertebrate brains, neurons, glial cells and synapses are plastic, which means that the physiology and structure of these components are modified in response to internal and external stimuli during development and in mature brains. The term plasticity has been introduced in the last century to describe experience-dependent changes in synapse strength and number. These changes result from local functional and morphological synapse modifications; however, these modifications also occur more commonly in pre- and postsynaptic neurons. As a result, neuron morphology and neuronal networks are constantly modified during the life of animals and humans in response to different stimuli. Nevertheless, it has been discovered in flies and mammals that the number of synapses and size and shape of neurons also oscillate during the day. In most cases, these rhythms are circadian since they are generated by endogenous circadian clocks; however, some rhythmic changes in neuron morphology and synapse number and structure are controlled directly by environmental cues or by both external cues and circadian clocks. When the circadian clock is involved in generating cyclic changes in the nervous system, this type of plasticity is called circadian plasticity. It seems to be important in processing sensory information, in learning and in memory. Disruption of the clock may affect major brain functions.
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Affiliation(s)
- Wojciech Krzeptowski
- Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Grzegorz Hess
- Department of Neurophysiology and Chronobiology, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland.,Institute of Pharmacology, Polish Academy of Sciences, Krakow, Poland
| | - Elżbieta Pyza
- Department of Cell Biology and Imaging, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
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17
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Ram A, Lo AW. Is Smaller Better? A Proposal to Use Bacteria For Neuroscientific Modeling. Front Comput Neurosci 2018; 12:7. [PMID: 29527158 PMCID: PMC5829041 DOI: 10.3389/fncom.2018.00007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 01/17/2018] [Indexed: 11/24/2022] Open
Abstract
Bacteria are easily characterizable model organisms with an impressively complicated set of abilities. Among them is quorum sensing, a cell-cell signaling system that may have a common evolutionary origin with eukaryotic cell-cell signaling. The two systems are behaviorally similar, but quorum sensing in bacteria is more easily studied in depth than cell-cell signaling in eukaryotes. Because of this comparative ease of study, bacterial dynamics are also more suited to direct interpretation than eukaryotic dynamics, e.g., those of the neuron. Here we review literature on neuron-like qualities of bacterial colonies and biofilms, including ion-based and hormonal signaling, and a phenomenon similar to the graded action potential. This suggests that bacteria could be used to help create more accurate and detailed biological models in neuroscientific research. More speculatively, bacterial systems may be considered an analog for neurons in biologically based computational research, allowing models to better harness the tremendous ability of biological organisms to process information and make decisions.
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Affiliation(s)
- Archana Ram
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Andrew W. Lo
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, United States
- Sloan School of Management, Massachusetts Institute of Technology, Cambridge, MA, United States
- Laboratory for Financial Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States
- Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology, Cambridge, MA, United States
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18
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Reichert H. How the humble insect brain became a powerful experimental model system. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2017; 203:879-889. [PMID: 28831545 DOI: 10.1007/s00359-017-1206-4] [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: 07/20/2017] [Revised: 08/10/2017] [Accepted: 08/10/2017] [Indexed: 10/19/2022]
Abstract
In the 21st century, neurobiological studies focused on the insect brain are revealing unprecedented insight into the molecular, cellular, developmental, and circuit aspects of brain organization and function, notably in the genetic model system of Drosophila melanogaster. Underlying this accelerating progress in understanding the insect brain is a century-long history of ground breaking experimental investigation, methodological advance, and conceptual insight catalyzed by the integration of two emerging research fields, neuroscience and genetics. This review traces some of the key early steps in this remarkable historical scientific adventure of exploring the brain of "these apparently humble representatives of life".
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19
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Ian E, Kirkerud NH, Galizia CG, Berg BG. Coincidence of pheromone and plant odor leads to sensory plasticity in the heliothine olfactory system. PLoS One 2017; 12:e0175513. [PMID: 28467500 PMCID: PMC5414983 DOI: 10.1371/journal.pone.0175513] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Accepted: 03/27/2017] [Indexed: 11/18/2022] Open
Abstract
Male moths possess a highly specialized olfactory system comprised of two segregated sub-arrangements dedicated to processing information about plant odors and pheromones, respectively. Communication between these two sub-systems has been described at the peripheral level, but relatively little is known about putative interactions at subsequent synaptic relays. The male moth faces the challenge of seeking out the conspecific female in a highly dynamic odor world. The female-produced pheromone blend, which is a limited resource serving as guidance for the male, will reach his antennae in intermittent pockets of odor filaments mixed with volatiles from various plants. In the present study we performed calcium imaging for measuring odor-evoked responses in the uni-glomerular antennal-lobe projection neurons (analog to mitral cells in the vertebrate olfactory bulb) of Helicoverpa armigera. In order to investigate putative interactions between the two sub-systems tuned to plant volatiles and pheromones, respectively, we performed repeated stimulations with a selection of biologically relevant odors. We found that paired stimulation with a plant odor and the pheromone led to suppressed responses in both sub-systems as compared to those evoked during initial stimulation including application of each odor stimulus alone. The fact that the suppression persisted also after pairing, indicates the existence of a Hebbian-like plasticity in the primary olfactory center established by temporal pairing of the two odor stimulation categories.
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Affiliation(s)
- Elena Ian
- Norwegian University of Science and Technology (NTNU), Department of Psychology, Trondheim, Norway
| | - Nicholas H. Kirkerud
- Norwegian University of Science and Technology (NTNU), Department of Psychology, Trondheim, Norway
- Universität Konstanz Fachbereich Biologie, Konstanz, Germany
| | | | - Bente G. Berg
- Norwegian University of Science and Technology (NTNU), Department of Psychology, Trondheim, Norway
- * E-mail:
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20
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dal Maschio M, Donovan JC, Helmbrecht TO, Baier H. Linking Neurons to Network Function and Behavior by Two-Photon Holographic Optogenetics and Volumetric Imaging. Neuron 2017; 94:774-789.e5. [DOI: 10.1016/j.neuron.2017.04.034] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 03/29/2017] [Accepted: 04/21/2017] [Indexed: 10/19/2022]
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21
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Uhlmann V, Ramdya P, Delgado-Gonzalo R, Benton R, Unser M. FlyLimbTracker: An active contour based approach for leg segment tracking in unmarked, freely behaving Drosophila. PLoS One 2017; 12:e0173433. [PMID: 28453566 PMCID: PMC5409058 DOI: 10.1371/journal.pone.0173433] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2017] [Accepted: 02/11/2017] [Indexed: 11/24/2022] Open
Abstract
Understanding the biological underpinnings of movement and action requires the development of tools for quantitative measurements of animal behavior. Drosophila melanogaster provides an ideal model for developing such tools: the fly has unparalleled genetic accessibility and depends on a relatively compact nervous system to generate sophisticated limbed behaviors including walking, reaching, grooming, courtship, and boxing. Here we describe a method that uses active contours to semi-automatically track body and leg segments from video image sequences of unmarked, freely behaving D. melanogaster. We show that this approach yields a more than 6-fold reduction in user intervention when compared with fully manual annotation and can be used to annotate videos with low spatial or temporal resolution for a variety of locomotor and grooming behaviors. FlyLimbTracker, the software implementation of this method, is open-source and our approach is generalizable. This opens up the possibility of tracking leg movements in other species by modifications of underlying active contour models.
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Affiliation(s)
- Virginie Uhlmann
- Biomedical Imaging Group, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- * E-mail: (PR); (VU)
| | - Pavan Ramdya
- Institute of Microengineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
- * E-mail: (PR); (VU)
| | - Ricard Delgado-Gonzalo
- Biomedical Imaging Group, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Richard Benton
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Michael Unser
- Biomedical Imaging Group, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
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22
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Roblodowski C, He Q. Drosophila Dunc-115 mediates axon projection through actin binding. INVERTEBRATE NEUROSCIENCE 2017; 17:2. [PMID: 28124181 DOI: 10.1007/s10158-017-0195-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 01/13/2017] [Indexed: 11/26/2022]
Abstract
A central step in organizing the central nervous system development is the growth cone of an axon navigating through guidance cues to reach its specific target. While a great deal of this process has been understood especially in identifying the extracellular guidance cues and their membrane receptors, much less is known about how guidance signals are further relayed to the actin filaments that are central to the mobility of the growth cone. The previous results from our laboratory have shown that Drosophila gene dunc-115 regulates axon projection in the eye and the central nervous system. Furthermore, Dunc-115 has a villin-headpiece (VHD) domain, implying the possibility of binding to actin. To further characterize Dunc-115's functions, we have identified the isoform Dunc-115L as a possible downstream target in relaying guidance cues further down to the cytoskeleton. Specifically, we have shown that Dunc-115 regulates neural connections in both the eye and the central nervous system in Drosophila and that Dunc-115 contains an actin-binding domain potentially capable of binding to actin filaments. In this report, we show that Dunc-115 binds to actin via its VHD domain directly, suggesting a possible mechanism for how Dunc-115 relays guidance signals.
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Affiliation(s)
- Christopher Roblodowski
- Department of Biology, Brooklyn College, City University of New York, 2900 Bedford Avenue, Brooklyn, NY, 11210, USA
- Department of Biological Sciences and Geology, Queensborough Community College, City University of New York, 222-05 56th Avenue, Bayside, NY, 11364, USA
| | - Qi He
- Department of Biology, Brooklyn College, City University of New York, 2900 Bedford Avenue, Brooklyn, NY, 11210, USA.
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23
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Corrales-Carvajal VM, Faisal AA, Ribeiro C. Internal states drive nutrient homeostasis by modulating exploration-exploitation trade-off. eLife 2016; 5. [PMID: 27770569 PMCID: PMC5108593 DOI: 10.7554/elife.19920] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 10/20/2016] [Indexed: 12/16/2022] Open
Abstract
Internal states can profoundly alter the behavior of animals. A quantitative understanding of the behavioral changes upon metabolic challenges is key to a mechanistic dissection of how animals maintain nutritional homeostasis. We used an automated video tracking setup to characterize how amino acid and reproductive states interact to shape exploitation and exploration decisions taken by adult Drosophila melanogaster. We find that these two states have specific effects on the decisions to stop at and leave proteinaceous food patches. Furthermore, the internal nutrient state defines the exploration-exploitation trade-off: nutrient-deprived flies focus on specific patches while satiated flies explore more globally. Finally, we show that olfaction mediates the efficient recognition of yeast as an appropriate protein source in mated females and that octopamine is specifically required to mediate homeostatic postmating responses without affecting internal nutrient sensing. Internal states therefore modulate specific aspects of exploitation and exploration to change nutrient selection. DOI:http://dx.doi.org/10.7554/eLife.19920.001 When making decisions, animals, including humans, do not always choose the same option. One reason for this is that their “internal state” changes the value of different options. This is particularly evident when deciding what type of food to eat. Depending on which nutrients the animal needs, it will choose to eat different foods. Amino acids are key nutrients that affect health, lifespan and reproduction. Female fruit flies that have recently mated, for example, eat more amino acids in order to obtain the raw materials required to produce eggs. Despite the importance of amino acids, little was known about how animal behavior changes in response to a lack of this nutrient. Corrales-Carvajal et al. used a video tracking system to measure the time that fruit flies – some of which had a need for amino acids – spent feeding on patches of yeast (which are rich in amino acids) versus patches of sucrose. Recently mated females – and virgins that had been fed a diet lacking in amino acids – consumed more yeast than sucrose, whereas virgin females that were not amino acid deficient showed the opposite pattern. To bias the fly toward eating the right food for their needs, several aspects of the fly’s behavior changed, including the number and length of individual feeding bouts. These different behaviors did not all change at the same time. The pattern of exploration taken by the flies also depended on their need for amino acids. Amino acid deficient flies spent most of their time near known yeast patches. By contrast, fully fed flies adopted a riskier foraging strategy, moving away from known sources of food to explore their environment more widely. In common with humans, the flies relied upon their sense of smell to efficiently identify different types of food. Overall, the results presented by Corrales-Carvajal et al. provide us with a detailed understanding about how changes to the internal state of the fly affect its behavior. The next step will be to use the powerful genetic tools available for studying fruit flies to reveal the neural circuits and molecular mechanisms that help animals find the types of food that they need. DOI:http://dx.doi.org/10.7554/eLife.19920.002
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Affiliation(s)
- Verónica María Corrales-Carvajal
- Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Lisbon, Portugal.,Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Aldo A Faisal
- Department of Bioengineering, Imperial College London, London, United Kingdom.,Department of Computing, Imperial College London, London, United Kingdom.,Integrative Biology Division, MRC Clinical Sciences Centre, London, United Kingdom
| | - Carlos Ribeiro
- Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Lisbon, Portugal
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24
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Lone SR, Venkataraman A, Srivastava M, Potdar S, Sharma VK. Or47b-neurons promote male-mating success in Drosophila. Biol Lett 2016; 11:20150292. [PMID: 26018835 DOI: 10.1098/rsbl.2015.0292] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Drosophila performs elaborate well-defined rituals of courtship, which involve several types of sensory inputs. Here, we report that Or47b-neurons promote male-mating success. Males with Or47b-neurons silenced/ablated exhibit reduced copulation frequency and increased copulation latency. Copulation latency of Or47b-manipulated flies increased proportionately with size of the assay arena, whereas in controls it remained unchanged. While competing for mates, Or47b-ablated males are outperformed by intact controls. These results suggest the role of Or47b-neurons in promoting male-mating success.
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Affiliation(s)
- Shahnaz Rahman Lone
- Chronobiology Laboratory, Evolutionary and Organismal Biology Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, PO Box 6436, Jakkur, Bangalore, Karnataka 560064, India
| | - Archana Venkataraman
- Chronobiology Laboratory, Evolutionary and Organismal Biology Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, PO Box 6436, Jakkur, Bangalore, Karnataka 560064, India
| | - Manishi Srivastava
- Chronobiology Laboratory, Evolutionary and Organismal Biology Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, PO Box 6436, Jakkur, Bangalore, Karnataka 560064, India
| | - Sheetal Potdar
- Chronobiology Laboratory, Evolutionary and Organismal Biology Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, PO Box 6436, Jakkur, Bangalore, Karnataka 560064, India
| | - Vijay Kumar Sharma
- Chronobiology Laboratory, Evolutionary and Organismal Biology Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, PO Box 6436, Jakkur, Bangalore, Karnataka 560064, India
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25
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Xu Y, Yan Y, He M, Liao Z, Ran D, Sun X, Liu Y, Wang X, Huang Y, Xu H, Gu H. A giant local interneuron modulates the rhythmic activities of the antennal lobe in Pupae Drosophila. Neurosci Lett 2015. [PMID: 26200249 DOI: 10.1016/j.neulet.2015.07.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
In Drosophila, olfaction is tightly related to feeding and reproduction. There are three classes of neurons forming synapses in the olfactory circuit: the olfactory receptor neurons (ORNs), projection neurons (PNs), and local interneurons (LNs). Here, we showed that giant local interneurons named GLNs, which were different from the classical neurons in the olfactory circuits, displayed distinctive rhythmic activities in the dorsolateral side of antennal lobe (AL) in Drosophila Pupae. Anatomically, GLNs were much larger than ipsilateral LNs and extended arborizations throughout the AL. Electrophysiologically, GLN exhibited typical 4-phased rhythmic spontaneous membrane activities, and the surrounding cells were dye-coupled when biocytin was injected into the cell body of GLN. Our study demonstrated that spontaneous activities of GLNs correlated with that of LNs and PNs. After the GLNs were damaged, the membrane activities of ipsilateral LNs and PNs became smaller, but faster. By depressing the firing frequencies of PNs and LNs, GLNs modulated the synchronization of AL and might play an important role as a "modulator" in the local circuit.
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Affiliation(s)
- Yanyang Xu
- Department of Anatomy and Neurobiology, Zhongshan School of Medicine, Sun Yat-sen University, 74 Zhongshan 2nd Road, Guangzhou 510080, PR China
| | - Ying Yan
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Key Laboratory of Natural Pesticide and Chemical Biology of the Ministry of Education, South China Agricultural University, Guangzhou 510642, PR China
| | - Mintong He
- Department of Anatomy and Neurobiology, Zhongshan School of Medicine, Sun Yat-sen University, 74 Zhongshan 2nd Road, Guangzhou 510080, PR China
| | - Zhiheng Liao
- Department of Anatomy and Neurobiology, Zhongshan School of Medicine, Sun Yat-sen University, 74 Zhongshan 2nd Road, Guangzhou 510080, PR China
| | - Dongzhi Ran
- Department of Anatomy and Neurobiology, Zhongshan School of Medicine, Sun Yat-sen University, 74 Zhongshan 2nd Road, Guangzhou 510080, PR China
| | - Xicui Sun
- Affiliated Psychiatric Hospital of Guangzhou, Medical College, Guangzhou 510080, PR China
| | - Yulou Liu
- Department of Anatomy and Neurobiology, Zhongshan School of Medicine, Sun Yat-sen University, 74 Zhongshan 2nd Road, Guangzhou 510080, PR China
| | - Xutian Wang
- Department of Anatomy and Neurobiology, Zhongshan School of Medicine, Sun Yat-sen University, 74 Zhongshan 2nd Road, Guangzhou 510080, PR China
| | - Yingcheng Huang
- Department of Anatomy and Neurobiology, Zhongshan School of Medicine, Sun Yat-sen University, 74 Zhongshan 2nd Road, Guangzhou 510080, PR China
| | - Hanhong Xu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Key Laboratory of Natural Pesticide and Chemical Biology of the Ministry of Education, South China Agricultural University, Guangzhou 510642, PR China.
| | - Huaiyu Gu
- Department of Anatomy and Neurobiology, Zhongshan School of Medicine, Sun Yat-sen University, 74 Zhongshan 2nd Road, Guangzhou 510080, PR China.
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26
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Bhatla N, Droste R, Sando SR, Huang A, Horvitz HR. Distinct Neural Circuits Control Rhythm Inhibition and Spitting by the Myogenic Pharynx of C. elegans. Curr Biol 2015; 25:2075-89. [PMID: 26212880 PMCID: PMC4546535 DOI: 10.1016/j.cub.2015.06.052] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Revised: 05/28/2015] [Accepted: 06/19/2015] [Indexed: 02/05/2023]
Abstract
Neural circuits have long been known to modulate myogenic muscles such as the heart, yet a mechanistic understanding at the cellular and molecular levels remains limited. We studied how light inhibits pumping of the Caenorhabditis elegans pharynx, a myogenic muscular pump for feeding, and found three neural circuits that alter pumping. First, light inhibits pumping via the I2 neuron monosynaptic circuit. Our electron microscopic reconstruction of the anterior pharynx revealed evidence for synapses from I2 onto muscle that were missing from the published connectome, and we show that these "missed synapses" are likely functional. Second, light inhibits pumping through the RIP-I1-MC neuron polysynaptic circuit, in which an inhibitory signal is likely transmitted from outside the pharynx into the pharynx in a manner analogous to how the mammalian autonomic nervous system controls the heart. Third, light causes a novel pharyngeal behavior, reversal of flow or "spitting," which is induced by the M1 neuron. These three neural circuits show that neurons can control a myogenic muscle organ not only by changing the contraction rate but also by altering the functional consequences of the contraction itself, transforming swallowing into spitting. Our observations also illustrate why connectome builders and users should be cognizant that functional synaptic connections might exist despite the absence of a declared synapse in the connectome.
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Affiliation(s)
- Nikhil Bhatla
- Howard Hughes Medical Institute, Department of Biology, McGovern Institute for Brain Research, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA; Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Rita Droste
- Howard Hughes Medical Institute, Department of Biology, McGovern Institute for Brain Research, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Steven R Sando
- Howard Hughes Medical Institute, Department of Biology, McGovern Institute for Brain Research, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Anne Huang
- Howard Hughes Medical Institute, Department of Biology, McGovern Institute for Brain Research, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - H Robert Horvitz
- Howard Hughes Medical Institute, Department of Biology, McGovern Institute for Brain Research, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
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27
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Hückesfeld S, Schoofs A, Schlegel P, Miroschnikow A, Pankratz MJ. Localization of Motor Neurons and Central Pattern Generators for Motor Patterns Underlying Feeding Behavior in Drosophila Larvae. PLoS One 2015; 10:e0135011. [PMID: 26252658 PMCID: PMC4529123 DOI: 10.1371/journal.pone.0135011] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Accepted: 07/16/2015] [Indexed: 11/19/2022] Open
Abstract
Motor systems can be functionally organized into effector organs (muscles and glands), the motor neurons, central pattern generators (CPG) and higher control centers of the brain. Using genetic and electrophysiological methods, we have begun to deconstruct the motor system driving Drosophila larval feeding behavior into its component parts. In this paper, we identify distinct clusters of motor neurons that execute head tilting, mouth hook movements, and pharyngeal pumping during larval feeding. This basic anatomical scaffold enabled the use of calcium-imaging to monitor the neural activity of motor neurons within the central nervous system (CNS) that drive food intake. Simultaneous nerve- and muscle-recordings demonstrate that the motor neurons innervate the cibarial dilator musculature (CDM) ipsi- and contra-laterally. By classical lesion experiments we localize a set of CPGs generating the neuronal pattern underlying feeding movements to the subesophageal zone (SEZ). Lesioning of higher brain centers decelerated all feeding-related motor patterns, whereas lesioning of ventral nerve cord (VNC) only affected the motor rhythm underlying pharyngeal pumping. These findings provide a basis for progressing upstream of the motor neurons to identify higher regulatory components of the feeding motor system.
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28
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Kazama H. Systems neuroscience in Drosophila: Conceptual and technical advantages. Neuroscience 2015; 296:3-14. [DOI: 10.1016/j.neuroscience.2014.06.035] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Revised: 06/17/2014] [Accepted: 06/17/2014] [Indexed: 11/25/2022]
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29
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Tastekin I, Riedl J, Schilling-Kurz V, Gomez-Marin A, Truman J, Louis M. Role of the Subesophageal Zone in Sensorimotor Control of Orientation in Drosophila Larva. Curr Biol 2015; 25:1448-60. [DOI: 10.1016/j.cub.2015.04.016] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Revised: 04/02/2015] [Accepted: 04/08/2015] [Indexed: 01/14/2023]
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30
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Günay C, Sieling FH, Dharmar L, Lin WH, Wolfram V, Marley R, Baines RA, Prinz AA. Distal spike initiation zone location estimation by morphological simulation of ionic current filtering demonstrated in a novel model of an identified Drosophila motoneuron. PLoS Comput Biol 2015; 11:e1004189. [PMID: 25978332 PMCID: PMC4433181 DOI: 10.1371/journal.pcbi.1004189] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Accepted: 02/10/2015] [Indexed: 11/18/2022] Open
Abstract
Studying ion channel currents generated distally from the recording site is difficult because of artifacts caused by poor space clamp and membrane filtering. A computational model can quantify artifact parameters for correction by simulating the currents only if their exact anatomical location is known. We propose that the same artifacts that confound current recordings can help pinpoint the source of those currents by providing a signature of the neuron’s morphology. This method can improve the recording quality of currents initiated at the spike initiation zone (SIZ) that are often distal to the soma in invertebrate neurons. Drosophila being a valuable tool for characterizing ion currents, we estimated the SIZ location and quantified artifacts in an identified motoneuron, aCC/MN1-Ib, by constructing a novel multicompartmental model. Initial simulation of the measured biophysical channel properties in an isopotential Hodgkin-Huxley type neuron model partially replicated firing characteristics. Adding a second distal compartment, which contained spike-generating Na+ and K+ currents, was sufficient to simulate aCC’s in vivo activity signature. Matching this signature using a reconstructed morphology predicted that the SIZ is on aCC’s primary axon, 70 μm after the most distal dendritic branching point. From SIZ to soma, we observed and quantified selective morphological filtering of fast activating currents. Non-inactivating K+ currents are filtered ∼3 times less and despite their large magnitude at the soma they could be as distal as Na+ currents. The peak of transient component (NaT) of the voltage-activated Na+ current is also filtered more than the magnitude of slower persistent component (NaP), which can contribute to seizures. The corrected NaP/NaT ratio explains the previously observed discrepancy when the same channel is expressed in different cells. In summary, we used an in vivo signature to estimate ion channel location and recording artifacts, which can be applied to other neurons. The study of ion channels is essential both for understanding normal brain function and for finding drug targets to treat neurological disease. Traditional experimental techniques remain challenging for recording ion channel currents accurately because of their locations in the neuron. Computer modeling of the three dimensional structure of neurons can provide a correction estimate for the measurement error introduced by neuronal membranes. To achieve this, we developed a modeling approach to localize, and correct for, distant ion channels. We demonstrated this approach by constructing novel computer models of an identified insect motor neuron, which provides a powerful model for studying the central nervous system. Through the study of electrical activity and genetic manipulations, it has been found that the persistent sodium current contributes to seizure. By modeling three dimensional structure, we were able to predict the location of these currents in the neuron, which were more distal than expected. Localizing sodium channels allowed us to predict their properties at origin, which favorably matched isolated recordings of these channels in more compact cells. This result is important in validating the use of heterologous compact cells to study insect sodium channels, and also demonstrates the usefulness of the presented modeling approach for studying channel physiology more generally.
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Affiliation(s)
- Cengiz Günay
- Department of Biology, Emory University, Atlanta, Georgia, United States of America
| | - Fred H Sieling
- Department of Biology, Emory University, Atlanta, Georgia, United States of America; Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Logesh Dharmar
- Department of Biology, Emory University, Atlanta, Georgia, United States of America
| | - Wei-Hsiang Lin
- Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia, United States
| | - Verena Wolfram
- Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia, United States
| | - Richard Marley
- Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia, United States
| | - Richard A Baines
- Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia, United States
| | - Astrid A Prinz
- Department of Biology, Emory University, Atlanta, Georgia, United States of America
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Gepner R, Mihovilovic Skanata M, Bernat NM, Kaplow M, Gershow M. Computations underlying Drosophila photo-taxis, odor-taxis, and multi-sensory integration. eLife 2015; 4. [PMID: 25945916 PMCID: PMC4466338 DOI: 10.7554/elife.06229] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 05/05/2015] [Indexed: 12/31/2022] Open
Abstract
To better understand how organisms make decisions on the basis of temporally varying multi-sensory input, we identified computations made by Drosophila larvae responding to visual and optogenetically induced fictive olfactory stimuli. We modeled the larva's navigational decision to initiate turns as the output of a Linear-Nonlinear-Poisson cascade. We used reverse-correlation to fit parameters to this model; the parameterized model predicted larvae's responses to novel stimulus patterns. For multi-modal inputs, we found that larvae linearly combine olfactory and visual signals upstream of the decision to turn. We verified this prediction by measuring larvae's responses to coordinated changes in odor and light. We studied other navigational decisions and found that larvae integrated odor and light according to the same rule in all cases. These results suggest that photo-taxis and odor-taxis are mediated by a shared computational pathway. DOI:http://dx.doi.org/10.7554/eLife.06229.001 Living organisms can sense cues from their surroundings and respond in appropriate ways. For example, animals will often move towards the smell of food or away from potential threats, such as predators. However, it is not fully understood how an animal's nervous system is set up to allow sensory information to control how the animal navigates its environment. It is also not clear how animals ‘decide’ what to do when they receive conflicting information from different senses. Optogenetics is a technique that allows neuroscientists to control the activities of individual nerve cells simply by shining light on to them. Fruit fly larvae have a simple but well-studied nervous system, and they are nearly transparent, so scientists can use optogenetics to activate nerve cells in freely moving larvae. Fruit fly larvae move in a series of forward ‘runs’ and direction-changing ‘turns’ and use sensory cues to decide when to turn, how large of a turn to make, and whether to turn left or right. Gepner, Mihovilovic Skanata et al. used optogenetics to stimulate different combinations of sensory nerve cells in larvae, while tracking the larvae's movements to discover exactly what information they used to make these decisions. An independent study by Hernandez-Nunez et al. also used a similar approach. Fruit fly larvae are attracted towards scents from rotting fruit and are repelled by light—in particular, larvae are most sensitive to blue light but cannot detect red light. Therefore, Gepner, Mihovilovic Skanata et al. could expose the larvae to blue light to activate light-sensing nerve cells as normal, and use red light to activate odor-sensing nerve cells via optogenetics. These experiments showed that larvae changed direction more often when the level of blue light was increased or when the level of red light (which simulated the detection of odors from rotting fruits) was decreased. Analysis of the data from these experiments revealed that larvae essentially assign negative values to the blue light and positive values to the ‘odor-mimicking’ red light. The larvae then use the sum of these two values to dictate their next move. This suggests that navigation in response to both light and odors is supported by the same pathways in a larva's nervous system. The approach of using optogenetics in combination with quantitative analysis, as used in these two independent studies, is now opening the door to a more complete understanding of the connections between the activities of sensory nerve cells and perception and behavior. DOI:http://dx.doi.org/10.7554/eLife.06229.002
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Affiliation(s)
- Ruben Gepner
- Department of Physics, New York University, New York, United States
| | | | - Natalie M Bernat
- Department of Physics, New York University, New York, United States
| | - Margarita Kaplow
- Center for Neural Science, New York University, New York, United States
| | - Marc Gershow
- Department of Physics, New York University, New York, United States
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Emerging from the bottleneck: benefits of the comparative approach to modern neuroscience. Trends Neurosci 2015; 38:273-8. [PMID: 25800324 DOI: 10.1016/j.tins.2015.02.008] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Revised: 02/24/2015] [Accepted: 02/27/2015] [Indexed: 01/08/2023]
Abstract
Neuroscience has historically exploited a wide diversity of animal taxa. Recently, however, research has focused increasingly on a few model species. This trend has accelerated with the genetic revolution, as genomic sequences and genetic tools became available for a few species, which formed a bottleneck. This coalescence on a small set of model species comes with several costs that are often not considered, especially in the current drive to use mice explicitly as models for human diseases. Comparative studies of strategically chosen non-model species can complement model species research and yield more rigorous studies. As genetic sequences and tools become available for many more species, we are poised to emerge from the bottleneck and once again exploit the rich biological diversity offered by comparative studies.
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Pool AH, Kvello P, Mann K, Cheung SK, Gordon MD, Wang L, Scott K. Four GABAergic interneurons impose feeding restraint in Drosophila. Neuron 2014; 83:164-77. [PMID: 24991960 DOI: 10.1016/j.neuron.2014.05.006] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/02/2014] [Indexed: 10/25/2022]
Abstract
Feeding is dynamically regulated by the palatability of the food source and the physiological needs of the animal. How consumption is controlled by external sensory cues and internal metabolic state remains under intense investigation. Here, we identify four GABAergic interneurons in the Drosophila brain that establish a central feeding threshold which is required to inhibit consumption. Inactivation of these cells results in indiscriminate and excessive intake of all compounds, independent of taste quality or nutritional state. Conversely, acute activation of these neurons suppresses consumption of water and nutrients. The output from these neurons is required to gate activity in motor neurons that control meal initiation and consumption. Thus, our study reveals a layer of inhibitory control in feeding circuits that is required to suppress a latent state of unrestricted and nonselective consumption.
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Affiliation(s)
- Allan-Hermann Pool
- Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, University of California, Berkeley, 16 Barker Hall, Berkeley, CA 94720, USA
| | - Pal Kvello
- Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, University of California, Berkeley, 16 Barker Hall, Berkeley, CA 94720, USA; Howard Hughes Medical Institute, University of California, Berkeley, 16 Barker Hall, Berkeley, CA 94720, USA
| | - Kevin Mann
- Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, University of California, Berkeley, 16 Barker Hall, Berkeley, CA 94720, USA
| | - Samantha K Cheung
- Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, University of California, Berkeley, 16 Barker Hall, Berkeley, CA 94720, USA
| | - Michael D Gordon
- Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, University of California, Berkeley, 16 Barker Hall, Berkeley, CA 94720, USA
| | - Liming Wang
- Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, University of California, Berkeley, 16 Barker Hall, Berkeley, CA 94720, USA
| | - Kristin Scott
- Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, University of California, Berkeley, 16 Barker Hall, Berkeley, CA 94720, USA; Howard Hughes Medical Institute, University of California, Berkeley, 16 Barker Hall, Berkeley, CA 94720, USA.
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Schoofs A, Hückesfeld S, Schlegel P, Miroschnikow A, Peters M, Zeymer M, Spieß R, Chiang AS, Pankratz MJ. Selection of motor programs for suppressing food intake and inducing locomotion in the Drosophila brain. PLoS Biol 2014; 12:e1001893. [PMID: 24960360 PMCID: PMC4068981 DOI: 10.1371/journal.pbio.1001893] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Accepted: 05/15/2014] [Indexed: 12/20/2022] Open
Abstract
Central mechanisms by which specific motor programs are selected to achieve meaningful behaviors are not well understood. Using electrophysiological recordings from pharyngeal nerves upon central activation of neurotransmitter-expressing cells, we show that distinct neuronal ensembles can regulate different feeding motor programs. In behavioral and electrophysiological experiments, activation of 20 neurons in the brain expressing the neuropeptide hugin, a homolog of mammalian neuromedin U, simultaneously suppressed the motor program for food intake while inducing the motor program for locomotion. Decreasing hugin neuropeptide levels in the neurons by RNAi prevented this action. Reducing the level of hugin neuronal activity alone did not have any effect on feeding or locomotion motor programs. Furthermore, use of promoter-specific constructs that labeled subsets of hugin neurons demonstrated that initiation of locomotion can be separated from modulation of its motor pattern. These results provide insights into a neural mechanism of how opposing motor programs can be selected in order to coordinate feeding and locomotive behaviors.
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Affiliation(s)
- Andreas Schoofs
- Molecular Brain Physiology and Behavior, LIMES-Institute, University of Bonn, Germany
| | - Sebastian Hückesfeld
- Molecular Brain Physiology and Behavior, LIMES-Institute, University of Bonn, Germany
| | - Philipp Schlegel
- Molecular Brain Physiology and Behavior, LIMES-Institute, University of Bonn, Germany
| | - Anton Miroschnikow
- Molecular Brain Physiology and Behavior, LIMES-Institute, University of Bonn, Germany
| | - Marc Peters
- Molecular Brain Physiology and Behavior, LIMES-Institute, University of Bonn, Germany
| | - Malou Zeymer
- Molecular Brain Physiology and Behavior, LIMES-Institute, University of Bonn, Germany
| | - Roland Spieß
- Department of Forensic Entomology, Institute of Legal Medicine, Jena University Hospital, Germany
| | - Ann-Shyn Chiang
- Brain Research Center, National Tsing Hua University, Taiwan
| | - Michael J. Pankratz
- Molecular Brain Physiology and Behavior, LIMES-Institute, University of Bonn, Germany
- * E-mail:
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Gomez-Marin A, Louis M. Multilevel control of run orientation in Drosophila larval chemotaxis. Front Behav Neurosci 2014; 8:38. [PMID: 24592220 PMCID: PMC3923145 DOI: 10.3389/fnbeh.2014.00038] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2013] [Accepted: 01/24/2014] [Indexed: 11/21/2022] Open
Abstract
Chemotaxis is a powerful paradigm to study how orientation behavior is driven by sensory stimulation. Drosophila larvae navigate odor gradients by controlling the duration of their runs and the direction of their turns. Straight runs and wide-amplitude turns represent two extremes of a behavioral continuum. Here we establish that, on average, runs curl toward the direction of higher odor concentrations. We find that the orientation and strength of the local odor gradient perpendicular to the direction of motion modulates the orientation of individual runs in a gradual manner. We discuss how this error-correction mechanism, called weathervaning, contributes to larval chemotaxis. We use larvae with a genetically modified olfactory system to demonstrate that unilateral function restricted to a single olfactory sensory neuron (OSN) is sufficient to direct weathervaning. Our finding that bilateral sensing is not necessary to control weathervaning highlights the role of temporal sampling. A correlational analysis between sensory inputs and behavioral outputs suggests that weathervaning results from low-amplitude head casts implemented without interruption of the run. In addition, we report the involvement of a sensorimotor memory arising from previous reorientation events. Together, our results indicate that larval chemotaxis combines concurrent orientation strategies that involve complex computations on different timescales.
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Affiliation(s)
- Alex Gomez-Marin
- EMBL/CRG Research Unit in Systems Biology, Centre de Regulació Genòmica, Universitat Pombeu Fabra Barcelona, Spain ; Champalimaud Neuroscience Programme, Champalimaud Center for the Unknown Lisbon, Portugal
| | - Matthieu Louis
- EMBL/CRG Research Unit in Systems Biology, Centre de Regulació Genòmica, Universitat Pombeu Fabra Barcelona, Spain
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Liang L, Li Y, Potter CJ, Yizhar O, Deisseroth K, Tsien RW, Luo L. GABAergic projection neurons route selective olfactory inputs to specific higher-order neurons. Neuron 2013; 79:917-31. [PMID: 24012005 DOI: 10.1016/j.neuron.2013.06.014] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/04/2013] [Indexed: 11/16/2022]
Abstract
We characterize an inhibitory circuit motif in the Drosophila olfactory system, parallel inhibition, which differs from feedforward or feedback inhibition. Excitatory and GABAergic inhibitory projection neurons (ePNs and iPNs) each receive input from antennal lobe glomeruli and send parallel output to the lateral horn, a higher center implicated in regulating innate olfactory behavior. Ca(2+) imaging of specific lateral horn neurons as an olfactory readout revealed that iPNs selectively suppressed food-related odor responses, but spared signal transmission from pheromone channels. Coapplying food odorant did not affect pheromone signal transmission, suggesting that the differential effects likely result from connection specificity of iPNs, rather than a generalized inhibitory tone. Ca(2+) responses in the ePN axon terminals show no detectable suppression by iPNs, arguing against presynaptic inhibition as a primary mechanism. The parallel inhibition motif may provide specificity in inhibition to funnel specific olfactory information, such as food and pheromone, into distinct downstream circuits.
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Affiliation(s)
- Liang Liang
- Department of Biology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA; Department of Applied Physics, Stanford University, Stanford, CA 94305, USA
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Pech U, Dipt S, Barth J, Singh P, Jauch M, Thum AS, Fiala A, Riemensperger T. Mushroom body miscellanea: transgenic Drosophila strains expressing anatomical and physiological sensor proteins in Kenyon cells. Front Neural Circuits 2013; 7:147. [PMID: 24065891 PMCID: PMC3779816 DOI: 10.3389/fncir.2013.00147] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Accepted: 08/29/2013] [Indexed: 01/08/2023] Open
Abstract
The fruit fly Drosophila melanogaster represents a key model organism for analyzing how neuronal circuits regulate behavior. The mushroom body in the central brain is a particularly prominent brain region that has been intensely studied in several insect species and been implicated in a variety of behaviors, e.g., associative learning, locomotor activity, and sleep. Drosophila melanogaster offers the advantage that transgenes can be easily expressed in neuronal subpopulations, e.g., in intrinsic mushroom body neurons (Kenyon cells). A number of transgenes has been described and engineered to visualize the anatomy of neurons, to monitor physiological parameters of neuronal activity, and to manipulate neuronal function artificially. To target the expression of these transgenes selectively to specific neurons several sophisticated bi- or even multipartite transcription systems have been invented. However, the number of transgenes that can be combined in the genome of an individual fly is limited in practice. To facilitate the analysis of the mushroom body we provide a compilation of transgenic fruit flies that express transgenes under direct control of the Kenyon-cell specific promoter, mb247. The transgenes expressed are fluorescence reporters to analyze neuroanatomical aspects of the mushroom body, proteins to restrict ectopic gene expression to mushroom bodies, or fluorescent sensors to monitor physiological parameters of neuronal activity of Kenyon cells. Some of the transgenic animals compiled here have been published already, whereas others are novel and characterized here for the first time. Overall, the collection of transgenic flies expressing sensor and reporter genes in Kenyon cells facilitates combinations with binary transcription systems and might, ultimately, advance the physiological analysis of mushroom body function.
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Affiliation(s)
- Ulrike Pech
- Department of Molecular Neurobiology of Behavior, Georg-August-Universität Göttingen Göttingen, Germany
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Meyer A, Galizia CG, Nawrot MP. Local interneurons and projection neurons in the antennal lobe from a spiking point of view. J Neurophysiol 2013; 110:2465-74. [PMID: 24004530 DOI: 10.1152/jn.00260.2013] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Local computation in microcircuits is an essential feature of distributed information processing in vertebrate and invertebrate brains. The insect antennal lobe represents a spatially confined local network that processes high-dimensional and redundant peripheral input to compute an efficient odor code. Social insects can rely on a particularly rich olfactory receptor repertoire, and they exhibit complex odor-guided behaviors. This corresponds with a high anatomical complexity of their antennal lobe network. In the honeybee, a large number of glomeruli that receive sensory input are interconnected by a dense network of local interneurons (LNs). Uniglomerular projection neurons (PNs) integrate sensory and recurrent local network input into an efficient spatio-temporal odor code. To investigate the specific computational roles of LNs and PNs, we measured several features of sub- and suprathreshold single-cell responses to in vivo odor stimulation. Using a semisupervised cluster analysis, we identified a combination of five characteristic features as sufficient to separate LNs and PNs from each other, independent of the applied odor-stimuli. The two clusters differed significantly in all these five features. PNs showed a higher spontaneous subthreshold activation, assumed higher peak response rates and a more regular spiking pattern. LNs reacted considerably faster to the onset of a stimulus, and their responses were more reliable across stimulus repetitions. We discuss possible mechanisms that can explain our results, and we interpret cell-type-specific characteristics with respect to their functional relevance.
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Affiliation(s)
- Anneke Meyer
- Neuroinformatik/Theoretical Neuroscience, Institute of Biology, Freie Universität Berlin, Berlin, Germany
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41
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Lin CY, Chuang CC, Hua TE, Chen CC, Dickson BJ, Greenspan RJ, Chiang AS. A comprehensive wiring diagram of the protocerebral bridge for visual information processing in the Drosophila brain. Cell Rep 2013; 3:1739-53. [PMID: 23707064 DOI: 10.1016/j.celrep.2013.04.022] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Revised: 03/12/2013] [Accepted: 04/25/2013] [Indexed: 11/19/2022] Open
Abstract
How the brain perceives sensory information and generates meaningful behavior depends critically on its underlying circuitry. The protocerebral bridge (PB) is a major part of the insect central complex (CX), a premotor center that may be analogous to the human basal ganglia. Here, by deconstructing hundreds of PB single neurons and reconstructing them into a common three-dimensional framework, we have constructed a comprehensive map of PB circuits with labeled polarity and predicted directions of information flow. Our analysis reveals a highly ordered information processing system that involves directed information flow among CX subunits through 194 distinct PB neuron types. Circuitry properties such as mirroring, convergence, divergence, tiling, reverberation, and parallel signal propagation were observed; their functional and evolutional significance is discussed. This layout of PB neuronal circuitry may provide guidelines for further investigations on transformation of sensory (e.g., visual) input into locomotor commands in fly brains.
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Affiliation(s)
- Chih-Yung Lin
- Institute of Biotechnology and Department of Life Science, National Tsing Hua University, Hsinchu 30013, Taiwan
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42
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Albertson R, Tan V, Leads RR, Reyes M, Sullivan W, Casper-Lindley C. Mapping Wolbachia distributions in the adult Drosophila brain. Cell Microbiol 2013; 15:1527-44. [PMID: 23490256 DOI: 10.1111/cmi.12136] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Revised: 02/22/2013] [Accepted: 03/02/2013] [Indexed: 01/03/2023]
Abstract
The maternally inherited bacterium Wolbachia infects the germline of most arthropod species. Using Drosophila simulans and D. melanogaster, we demonstrate that localization of Wolbachia to the fat bodies and adult brain is likely also a conserved feature of Wolbachia infection. Examination of three Wolbachia strains (WMel , WRiv , WPop ) revealed that the bacteria preferentially concentrate in the central brain with low titres in the optic lobes. Distribution within regions of the central brain is largely determined by the Wolbachia strain, while the titre is influenced by both, the host species and the bacteria strain. In neurons of the central brain and ventral nerve cord, Wolbachia preferentially localizes to the neuronal cell bodies but not to axons. All examined Wolbachia strains are present intracellularly or in extracellular clusters, with the pathogenic WPop strain exhibiting the largest and most abundant clusters. We also discovered that 16 of 40 lines from the Drosophila Genetic Reference Panel are Wolbachia infected. Direct comparison of Wolbachia infected and cured lines from this panel reveals that differences in physiological traits (chill coma recovery, starvation, longevity) are partially due to host line influences. In addition, a tetracycline-induced increase in Drosophila longevity was detected many generations after treatment.
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Abstract
Temperature sensation has a strong impact on animal behavior and is necessary for animals to avoid exposure to harmful temperatures. It is now well known that thermoTRP (transient receptor potential) channels in thermosensory neurons detect a variable range of temperature stimuli. However, little is known about how a range of temperature information is relayed and integrated in the neural circuits. Here, we show novel temperature integration between two warm inputs via Drosophila TRPA channels, TRPA1 and Pyrexia (Pyx). The internal AC (anterior cell) thermosensory neurons, which express TRPA1, detect warm temperatures and mediate temperature preference behavior. We found that the AC neurons were activated twice when subjected to increasing temperatures. The first response was at ∼25°C via TRPA1 channel, which is expressed in the AC neurons. The second response was at ∼27°C via the second antennal segments, indicating that the second antennal segments are involved in the detection of warm temperatures. Further analysis reveals that pyx-Gal4-expressing neurons have synapses on the AC neurons and that mutation of pyx eliminates the second response of the AC neurons. These data suggest that AC neurons integrate both their own TRPA1-dependent temperature responses and a Pyx-dependent temperature response from the second antennal segments. Our data reveal the first identification of temperature integration, which combines warm temperature information from peripheral to central neurons and provides the possibility that temperature integration is involved in the plasticity of behavioral outputs.
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Abstract
The visual neurons of many animals process sensory input differently depending on the animal's state of locomotion. Now, new work in Drosophila melanogaster shows that neuromodulatory neurons active during flight boost responses of neurons in the visual system.
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Affiliation(s)
- Vivek Jayaraman
- Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA.
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45
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Brown SR. Emergence in the central nervous system. Cogn Neurodyn 2012; 7:173-95. [PMID: 24427200 DOI: 10.1007/s11571-012-9229-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Revised: 10/04/2012] [Accepted: 11/20/2012] [Indexed: 11/30/2022] Open
Abstract
"Emergence" is an idea that has received much attention in consciousness literature, but it is difficult to find characterizations of that concept which are both specific and useful. I will precisely define and characterize a type of epistemic ("weak") emergence and show that it is a property of some neural circuits throughout the CNS, on micro-, meso- and macroscopic levels. I will argue that possession of this property can result in profoundly altered neural dynamics on multiple levels in cortex and other systems. I will first describe emergent neural entities (ENEs) abstractly. I will then show how ENEs function specifically and concretely, and demonstrate some implications of this type of emergence for the CNS.
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Affiliation(s)
- Steven Ravett Brown
- Department of Neuroscience, Mt. Sinai School of Medicine, Icahn Medical Institute, 1425 Madison Ave, Rm 10-70E, New York, NY 10029 USA ; 158 W 23rd St, Fl 3, New York, NY 10011 USA
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Pavlou HJ, Goodwin SF. Courtship behavior in Drosophila melanogaster: towards a 'courtship connectome'. Curr Opin Neurobiol 2012; 23:76-83. [PMID: 23021897 PMCID: PMC3563961 DOI: 10.1016/j.conb.2012.09.002] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Revised: 08/29/2012] [Accepted: 09/08/2012] [Indexed: 01/24/2023]
Abstract
The construction of a comprehensive structural, and importantly functional map of the network of elements and connections forming the brain represents the Holy Grail for research groups working in disparate disciplines. Although technical limitations have restricted the mapping of human and mouse ‘connectomes’ to the level of brain regions, a finer degree of functional resolution is attainable in the fruit fly, Drosophila melanogaster, due to the armamentarium of genetic tools available for this model organism. Currently, one of the most amenable approaches employed by Drosophila neurobiologists involves mapping neuronal circuitry underlying complex innate behaviors – courtship being a classic paradigm. We discuss recent studies aimed at identifying the cellular components of courtship neural circuits, mapping function in these circuits and defining causal relationships between neural activity and behavior.
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Affiliation(s)
- Hania J Pavlou
- Department of Physiology, Anatomy & Genetics, University of Oxford, Oxford, OX1 3PT, UK
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Chen GY, Wu CC, Shao HC, Chang HM, Chiang AS, Chen YC. Retention of features on a mapped Drosophila brain surface using a Bézier-tube-based surface model averaging technique. IEEE Trans Biomed Eng 2012; 59:3314-26. [PMID: 22922691 DOI: 10.1109/tbme.2012.2214774] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Model averaging is a widely used technique in biomedical applications. Two established model averaging methods, iterative shape averaging (ISA) method and virtual insect brain (VIB) method, have been applied to several organisms to generate average representations of their brain surfaces. However, without sufficient samples, some features of the average Drosophila brain surface obtained using the above methods may disappear or become distorted. To overcome this problem, we propose a Bézier-tube-based surface model averaging strategy. The proposed method first compensates for disparities in position, orientation, and dimension of input surfaces, and then evaluates the average surface by performing shape-based interpolation. Structural features with larger individual disparities are simplified with half-ellipse-shaped Bézier tubes, and are unified according to these tubes to avoid distortion during the averaging process. Experimental results show that the average model yielded by our method could preserve fine features and avoid structural distortions even if only a limit amount of input samples are used. Finally, we qualitatively compare our results with those obtained by ISA and VIB methods by measuring the surface-to-surface distances between input surfaces and the averaged ones. The comparisons show that the proposed method could generate a more representative average surface than both ISA and VIB methods.
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Affiliation(s)
- Guan-Yu Chen
- Department of Electrical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
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Zhou Y, Wilson RI. Transduction in Drosophila olfactory receptor neurons is invariant to air speed. J Neurophysiol 2012; 108:2051-9. [PMID: 22815404 DOI: 10.1152/jn.01146.2011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
In the vertebrate nose, increasing air speed tends to increase the magnitude of odor-evoked activity in olfactory receptor neurons (ORNs), given constant odor concentration and duration. It is often assumed that the same is true of insect olfactory organs, but this has not been directly tested. In this study, we examined the effect of air speed on ORN responses in Drosophila melanogaster. We constructed an odor delivery device that allowed us to independently vary concentration and air speed, and we used a fast photoionization detector to precisely measure the actual odor concentration at the antenna while simultaneously recording spikes from ORNs in vivo. Our results demonstrate that Drosophila ORN odor responses are invariant to air speed, as long as odor concentration is kept constant. This finding was true across a >100-fold range of air speeds. Because odor hydrophobicity has been proposed to affect the air speed dependence of olfactory transduction, we tested a >1,000-fold range of hydrophobicity values and found that ORN responses are invariant to air speed across this full range. These results have implications for the mechanisms of odor delivery to Drosophila ORNs. Our findings are also significant because flies have a limited ability to control air flow across their antennae, unlike terrestrial vertebrates, which can control air flow within their nasal cavity. Thus, for the fly, invariance to air speed may be adaptive because it confers robustness to changing wind conditions.
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Affiliation(s)
- Yi Zhou
- Department of Neurobiology, Harvard Medical School, Boston, Massachusetts 02115, USA
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Schmold N, Syed NI. Molluscan neurons in culture: shedding light on synapse formation and plasticity. J Mol Histol 2012; 43:383-99. [PMID: 22538479 DOI: 10.1007/s10735-012-9398-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Accepted: 02/20/2012] [Indexed: 12/29/2022]
Abstract
From genes to behaviour, the simple model system approach has played many pivotal roles in deciphering nervous system function in both invertebrates and vertebrates. However, with the advent of sophisticated imaging and recording techniques enabling the direct investigation of single vertebrate neurons, the utility of simple invertebrate organisms as model systems has been put to question. To address this subject meaningfully and comprehensively, we first review the contributions made by invertebrates in the field of neuroscience over the years, paving the way for similar breakthroughs in higher animals. In particular, we focus on molluscan (Lymnaea, Aplysia, and Helisoma) and leech (Hirudo) models and the pivotal roles they have played in elucidating mechanisms of synapse formation and plasticity. While the ultimate goal in neuroscience is to understand the workings of the human brain in both its normal and diseased states, the sheer complexity of most vertebrate models still makes it difficult to define the underlying principles of nervous system function. Investigators have thus turned to invertebrate models, which are unique with respect to their simple nervous systems that are endowed with a finite number of large, individually identifiable neurons of known function. We start off by discussing in vivo and semi-intact preparations, regarding their amenability to simple circuit analysis. Despite the 'simplicity' of invertebrate nervous systems however, it is still difficult to study individual synaptic connections in detail. We therefore emphasize in the next section, the utility of studying identified invertebrate neurons in vitro, to directly examine the development, specificity, and plasticity of synaptic connections in a well-defined environment, at a resolution that it is still unapproachable in the intact brain. We conclude with a discussion of the future of invertebrates in neuroscience in elucidating mechanisms of neurological disease and developing neuron-silicon interfaces.
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Affiliation(s)
- Nichole Schmold
- Department of Cell Biology and Anatomy, Hotchkiss Brain Institute, Faculty of Medicine, University of Calgary, Calgary, Canada0.
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Eschbach C, Cano C, Haberkern H, Schraut K, Guan C, Triphan T, Gerber B. Associative learning between odorants and mechanosensory punishment in larval Drosophila. ACTA ACUST UNITED AC 2012; 214:3897-905. [PMID: 22071180 DOI: 10.1242/jeb.060533] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We tested whether Drosophila larvae can associate odours with a mechanosensory disturbance as a punishment, using substrate vibration conveyed by a loudspeaker (buzz:). One odour (A) was presented with the buzz, while another odour (B) was presented without the buzz (A/B training). Then, animals were offered the choice between A and B. After reciprocal training (A/B), a second experimental group was tested in the same way. We found that larvae show conditioned escape from the previously punished odour. We further report an increase of associative performance scores with the number of punishments, and an increase according to the number of training cycles. Within the range tested (between 50 and 200 Hz), however, the pitch of the buzz does not apparently impact associative success. Last, but not least, we characterized odour-buzz memories with regard to the conditions under which they are behaviourally expressed--or not. In accordance with what has previously been found for associative learning between odours and bad taste (such as high concentration salt or quinine), we report that conditioned escape after odour-buzz learning is disabled if escape is not warranted, i.e. if no punishment to escape from is present during testing. Together with the already established paradigms for the association of odour and bad taste, the present assay offers the prospect of analysing how a relatively simple brain orchestrates memory and behaviour with regard to different kinds of 'bad' events.
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Affiliation(s)
- Claire Eschbach
- Universität Würzburg, Biozentrum, Neurobiologie und Genetik, Würzburg, Germany
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