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Yoshikawa S, Tang P, Simpson JH. Mechanosensory and command contributions to the Drosophila grooming sequence. Curr Biol 2024; 34:2066-2076.e3. [PMID: 38657610 PMCID: PMC11179149 DOI: 10.1016/j.cub.2024.04.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 02/14/2024] [Accepted: 04/02/2024] [Indexed: 04/26/2024]
Abstract
Flies groom in response to competing mechanosensory cues in an anterior-to-posterior order using specific legs. From behavior screens, we identified a pair of cholinergic command-like neurons, Mago-no-Te (MGT), whose optogenetic activation elicits thoracic grooming by the back legs. Thoracic grooming is typically composed of body sweeps and leg rubs in alternation, but clonal analysis coupled with amputation experiments revealed that MGT activation only commands the body sweeps: initiation of leg rubbing requires contact between the leg and thorax. With new electron microscopy (EM) connectome data for the ventral nerve cord (VNC), we uncovered a circuit-based explanation for why stimulation of posterior thoracic mechanosensory bristles initiates cleaning by the back legs. Our previous work showed that flies weigh mechanosensory inputs across the body to select which part to groom, but we did not know why the thorax was always cleaned last. Here, the connectome for the VNC enabled us to identify a pair of GABAergic inhibitory neurons, UMGT1, that receives diverse sensory inputs and synapses onto both MGT and components of its downstream circuits. Optogenetic activation of UMGT1 suppresses thoracic cleaning, representing a mechanism by which mechanosensory stimuli on other body parts could take precedence in the grooming hierarchy. We also anatomically mapped the pre-motor circuit downstream of MGT, including inhibitory feedback connections that may enable rhythmicity and coordination of limb movement during thoracic grooming. The combination of behavioral screens and connectome analysis allowed us to identify a neural circuit connecting sensory-to-motor neurons that contributes to thoracic grooming.
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Affiliation(s)
- Shingo Yoshikawa
- Department of Molecular, Cellular, and Developmental Biology, Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Paul Tang
- Department of Molecular, Cellular, and Developmental Biology, Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Julie H Simpson
- Department of Molecular, Cellular, and Developmental Biology, Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA.
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2
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Gomez A, Gonzalez S, Oke A, Luo J, Duong JB, Esquerra RM, Zimmerman T, Capponi S, Fung JC, Nystul TG. A high-throughput method for quantifying Drosophila fecundity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.27.587093. [PMID: 38585877 PMCID: PMC10996622 DOI: 10.1101/2024.03.27.587093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
Measurements of Drosophila fecundity are used in a wide variety of studies, such as investigations of stem cell biology, nutrition, behavior, and toxicology. In addition, because fecundity assays are performed on live flies, they are suitable for longitudinal studies such as investigations of aging or prolonged chemical exposure. However, standard Drosophila fecundity assays have been difficult to perform in a high-throughput manner because experimental factors such as the physiological state of the flies and environmental cues must be carefully controlled to achieve consistent results. In addition, exposing flies to a large number of different experimental conditions (such as chemical additives in the diet) and manually counting the number of eggs laid to determine the impact on fecundity is time-consuming. We have overcome these challenges by combining a new multiwell fly culture strategy with a novel 3D-printed fly transfer device to rapidly and accurately transfer flies from one plate to another; the RoboCam, a low-cost, custom built robotic camera to capture images of the wells automatically; and an image segmentation pipeline to automatically identify and quantify eggs. We show that this method is compatible with robust and consistent egg laying throughout the assay period; and demonstrate that the automated pipeline for quantifying fecundity is very accurate (r2 = 0.98 for the correlation between the automated egg counts and the ground truth) In addition, we show that this method can be used to efficiently detect the effects on fecundity induced by dietary exposure to chemicals. Taken together, this strategy substantially increases the efficiency and reproducibility of high throughput egg laying assays that require exposing flies to multiple different media conditions.
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Affiliation(s)
- Andreana Gomez
- University of California, San Francisco, Department of Anatomy
| | - Sergio Gonzalez
- San Francisco State University, Department of Biology
- Center for Cellular Construction, San Francisco, CA
| | - Ashwini Oke
- San Francisco State University, Department of Chemistry and Biochemistry; University of California, San Francisco, OB/GYN Department
- IBM Almaden Research Center, San Jose, CA; University of California, San Francisco, Center for Reproductive Sciences
| | - Jiayu Luo
- San Francisco State University, Department of Biology
- Center for Cellular Construction, San Francisco, CA
| | - Johnny B Duong
- Center for Cellular Construction, San Francisco, CA
- San Francisco State University, Department of Chemistry and Biochemistry; University of California, San Francisco, OB/GYN Department
| | - Raymond M Esquerra
- Center for Cellular Construction, San Francisco, CA
- San Francisco State University, Department of Chemistry and Biochemistry; University of California, San Francisco, OB/GYN Department
| | - Thomas Zimmerman
- Center for Cellular Construction, San Francisco, CA
- IBM Almaden Research Center, San Jose, CA; University of California, San Francisco, Center for Reproductive Sciences
| | - Sara Capponi
- Center for Cellular Construction, San Francisco, CA
- IBM Almaden Research Center, San Jose, CA; University of California, San Francisco, Center for Reproductive Sciences
| | - Jennifer C Fung
- San Francisco State University, Department of Chemistry and Biochemistry; University of California, San Francisco, OB/GYN Department
- IBM Almaden Research Center, San Jose, CA; University of California, San Francisco, Center for Reproductive Sciences
- University of California, San Francisco EaRTH Center
| | - Todd G Nystul
- University of California, San Francisco, Department of Anatomy
- San Francisco State University, Department of Chemistry and Biochemistry; University of California, San Francisco, OB/GYN Department
- IBM Almaden Research Center, San Jose, CA; University of California, San Francisco, Center for Reproductive Sciences
- University of California, San Francisco EaRTH Center
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Simpson JH. Descending control of motor sequences in Drosophila. Curr Opin Neurobiol 2024; 84:102822. [PMID: 38096757 PMCID: PMC11215313 DOI: 10.1016/j.conb.2023.102822] [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] [Received: 08/01/2023] [Revised: 11/22/2023] [Accepted: 11/22/2023] [Indexed: 02/18/2024]
Abstract
The descending neurons connecting the fly's brain to its ventral nerve cord respond to sensory stimuli and evoke motor programs of varying complexity. Anatomical characterization of the descending neurons and their synaptic connections suggests how these circuits organize movements, while optogenetic manipulation of their activity reveals what behaviors they can induce. Monitoring their responses to sensory stimuli or during behavior performance indicates what information they may encode. Recent advances in all three approaches make the descending neurons an excellent place to better understand the sensorimotor integration and transformation required for nervous systems to govern the motor sequences that constitute animal behavior.
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Affiliation(s)
- Julie H Simpson
- Dept. Molecular Cellular and Developmental Biology and Neuroscience Research Institute, University of California Santa Barbara, USA.
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4
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Wu SF, Yang CH. Insect neurobiology: Oviposition crowd control. Curr Biol 2024; 34:R28-R30. [PMID: 38194925 DOI: 10.1016/j.cub.2023.11.050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2024]
Abstract
A new study examines how Helicoverpa armigera females detect chemicals released by conspecific eggs in order to avoid laying more eggs on the same substrate. This work opens new avenues for basic research inquiries and offers a potential strategy for controlling insect pests.
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Affiliation(s)
- Shun-Fan Wu
- College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China.
| | - Chung-Hui Yang
- Department of Neurobiology, Duke University Medical School, Durham, NC 27710, USA.
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5
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Oliveira-Ferreira C, Gaspar M, Vasconcelos ML. Neuronal substrates of egg-laying behaviour at the abdominal ganglion of Drosophila melanogaster. Sci Rep 2023; 13:21941. [PMID: 38081887 PMCID: PMC10713638 DOI: 10.1038/s41598-023-48109-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Accepted: 11/22/2023] [Indexed: 12/18/2023] Open
Abstract
Egg-laying in Drosophila is the product of post-mating physiological and behavioural changes that culminate in a stereotyped sequence of actions. Egg-laying harbours a great potential as a paradigm to uncover how the appropriate motor circuits are organized and activated to generate behaviour. To study this programme, we first describe the different phases of the egg-laying programme and the specific actions associated with each phase. Using a combination of neuronal activation and silencing experiments, we identify neurons (OvAbg) in the abdominal ganglion as key players in egg-laying. To generate and functionally characterise subsets of OvAbg, we used an intersectional approach with neurotransmitter specific lines-VGlut, Cha and Gad1. We show that OvAbg/VGlut neurons promote initiation of egg deposition in a mating status dependent way. OvAbg/Cha neurons are required in exploration and egg deposition phases, though activation leads specifically to egg expulsion. Experiments with the OvAbg/Gad1 neurons show they participate in egg deposition. We further show a functional connection of OvAbg neurons with brain neurons. This study provides insight into the organization of neuronal circuits underlying complex motor behaviour.
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Affiliation(s)
| | - Miguel Gaspar
- Neuroscience Programme, Champalimaud Foundation, Lisbon, Portugal
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Auth CS, Crickmore MA. Behavioral neuroscience: Computation in individual neurons. Curr Biol 2023; 33:R1006-R1008. [PMID: 37816318 DOI: 10.1016/j.cub.2023.08.048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/12/2023]
Abstract
Information coding is generally thought to emerge from fast activity across thousands of neurons. A recent study shows that many features of a sophisticated decision-action sequence are encoded by the slow activity of individual command neurons.
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Affiliation(s)
- Charlotte S Auth
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.
| | - Michael A Crickmore
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.
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7
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Vijayan V, Wang F, Wang K, Chakravorty A, Adachi A, Akhlaghpour H, Dickson BJ, Maimon G. A rise-to-threshold process for a relative-value decision. Nature 2023; 619:563-571. [PMID: 37407812 PMCID: PMC10356611 DOI: 10.1038/s41586-023-06271-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 05/26/2023] [Indexed: 07/07/2023]
Abstract
Whereas progress has been made in the identification of neural signals related to rapid, cued decisions1-3, less is known about how brains guide and terminate more ethologically relevant decisions in which an animal's own behaviour governs the options experienced over minutes4-6. Drosophila search for many seconds to minutes for egg-laying sites with high relative value7,8 and have neurons, called oviDNs, whose activity fulfills necessity and sufficiency criteria for initiating the egg-deposition motor programme9. Here we show that oviDNs express a calcium signal that (1) dips when an egg is internally prepared (ovulated), (2) drifts up and down over seconds to minutes-in a manner influenced by the relative value of substrates-as a fly determines whether to lay an egg and (3) reaches a consistent peak level just before the abdomen bend for egg deposition. This signal is apparent in the cell bodies of oviDNs in the brain and it probably reflects a behaviourally relevant rise-to-threshold process in the ventral nerve cord, where the synaptic terminals of oviDNs are located and where their output can influence behaviour. We provide perturbational evidence that the egg-deposition motor programme is initiated once this process hits a threshold and that subthreshold variation in this process regulates the time spent considering options and, ultimately, the choice taken. Finally, we identify a small recurrent circuit that feeds into oviDNs and show that activity in each of its constituent cell types is required for laying an egg. These results argue that a rise-to-threshold process regulates a relative-value, self-paced decision and provide initial insight into the underlying circuit mechanism for building this process.
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Affiliation(s)
- Vikram Vijayan
- Laboratory of Integrative Brain Function and Howard Hughes Medical Institute, The Rockefeller University, New York, NY, USA.
| | - Fei Wang
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
| | - Kaiyu Wang
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
- Lingang Laboratory, Shanghai Center for Brain Science and Brain-Inspired Intelligence Technology, Shanghai, China
| | - Arun Chakravorty
- Laboratory of Integrative Brain Function and Howard Hughes Medical Institute, The Rockefeller University, New York, NY, USA
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Atsuko Adachi
- Laboratory of Integrative Brain Function and Howard Hughes Medical Institute, The Rockefeller University, New York, NY, USA
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA
| | - Hessameddin Akhlaghpour
- Laboratory of Integrative Brain Function and Howard Hughes Medical Institute, The Rockefeller University, New York, NY, USA
| | - Barry J Dickson
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
- Queensland Brain Institute, University of Queensland, St Lucia, Queensland, Australia
| | - Gaby Maimon
- Laboratory of Integrative Brain Function and Howard Hughes Medical Institute, The Rockefeller University, New York, NY, USA.
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Álvarez-Ocaña R, Shahandeh MP, Ray V, Auer TO, Gompel N, Benton R. Odor-regulated oviposition behavior in an ecological specialist. Nat Commun 2023; 14:3041. [PMID: 37236992 DOI: 10.1038/s41467-023-38722-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 05/10/2023] [Indexed: 05/28/2023] Open
Abstract
Colonization of a novel ecological niche can require, or be driven by, evolution of an animal's behaviors promoting their reproductive success. We investigated the evolution and sensory basis of oviposition in Drosophila sechellia, a close relative of Drosophila melanogaster that exhibits extreme specialism for Morinda citrifolia noni fruit. D. sechellia produces fewer eggs than other drosophilids and lays these almost exclusively on noni substrates. We show that visual, textural and social cues do not explain this species-specific preference. By contrast, we find that loss of olfactory input in D. sechellia, but not D. melanogaster, essentially abolishes egg-laying, suggesting that olfaction gates gustatory-driven noni preference. Noni odors are detected by redundant olfactory pathways, but we discover a role for hexanoic acid and the cognate Ionotropic receptor 75b (Ir75b) in odor-evoked oviposition. Through receptor exchange in D. melanogaster, we provide evidence for a causal contribution of odor-tuning changes in Ir75b to the evolution of D. sechellia's oviposition behavior.
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Affiliation(s)
- Raquel Álvarez-Ocaña
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015, Lausanne, Switzerland
| | - Michael P Shahandeh
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015, Lausanne, Switzerland
| | - Vijayaditya Ray
- Evolutionary Ecology, Ludwig-Maximilians Universität München, Fakultät für Biologie, Biozentrum, Grosshaderner Strasse 2, 82152, Planegg-Martinsried, Germany
| | - Thomas O Auer
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015, Lausanne, Switzerland
| | - Nicolas Gompel
- Evolutionary Ecology, Ludwig-Maximilians Universität München, Fakultät für Biologie, Biozentrum, Grosshaderner Strasse 2, 82152, Planegg-Martinsried, Germany
| | - Richard Benton
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015, Lausanne, Switzerland.
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