1
|
Ganguly I, Heckman EL, Litwin-Kumar A, Clowney EJ, Behnia R. Diversity of visual inputs to Kenyon cells of the Drosophila mushroom body. Nat Commun 2024; 15:5698. [PMID: 38972924 PMCID: PMC11228034 DOI: 10.1038/s41467-024-49616-z] [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: 01/24/2024] [Accepted: 06/11/2024] [Indexed: 07/09/2024] Open
Abstract
The arthropod mushroom body is well-studied as an expansion layer representing olfactory stimuli and linking them to contingent events. However, 8% of mushroom body Kenyon cells in Drosophila melanogaster receive predominantly visual input, and their function remains unclear. Here, we identify inputs to visual Kenyon cells using the FlyWire adult whole-brain connectome. Input repertoires are similar across hemispheres and connectomes with certain inputs highly overrepresented. Many visual neurons presynaptic to Kenyon cells have large receptive fields, while interneuron inputs receive spatially restricted signals that may be tuned to specific visual features. Individual visual Kenyon cells randomly sample sparse inputs from combinations of visual channels, including multiple optic lobe neuropils. These connectivity patterns suggest that visual coding in the mushroom body, like olfactory coding, is sparse, distributed, and combinatorial. However, the specific input repertoire to the smaller population of visual Kenyon cells suggests a constrained encoding of visual stimuli.
Collapse
Affiliation(s)
- Ishani Ganguly
- Department of Neuroscience, Columbia University, New York, NY, USA
- Center for Theoretical Neuroscience, Columbia University, New York, NY, USA
- Zuckerman Institute, Columbia University, New York, NY, USA
| | - Emily L Heckman
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Ashok Litwin-Kumar
- Department of Neuroscience, Columbia University, New York, NY, USA
- Center for Theoretical Neuroscience, Columbia University, New York, NY, USA
- Zuckerman Institute, Columbia University, New York, NY, USA
| | - E Josephine Clowney
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, USA.
- Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI, USA.
| | - Rudy Behnia
- Department of Neuroscience, Columbia University, New York, NY, USA.
- Zuckerman Institute, Columbia University, New York, NY, USA.
- Kavli Institute for Brain Science, Columbia University, New York, NY, USA.
| |
Collapse
|
2
|
Cheong HSJ, Boone KN, Bennett MM, Salman F, Ralston JD, Hatch K, Allen RF, Phelps AM, Cook AP, Phelps JS, Erginkaya M, Lee WCA, Card GM, Daly KC, Dacks AM. Organization of an ascending circuit that conveys flight motor state in Drosophila. Curr Biol 2024; 34:1059-1075.e5. [PMID: 38402616 PMCID: PMC10939832 DOI: 10.1016/j.cub.2024.01.071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 12/08/2023] [Accepted: 01/29/2024] [Indexed: 02/27/2024]
Abstract
Natural behaviors are a coordinated symphony of motor acts that drive reafferent (self-induced) sensory activation. Individual sensors cannot disambiguate exafferent (externally induced) from reafferent sources. Nevertheless, animals readily differentiate between these sources of sensory signals to carry out adaptive behaviors through corollary discharge circuits (CDCs), which provide predictive motor signals from motor pathways to sensory processing and other motor pathways. Yet, how CDCs comprehensively integrate into the nervous system remains unexplored. Here, we use connectomics, neuroanatomical, physiological, and behavioral approaches to resolve the network architecture of two pairs of ascending histaminergic neurons (AHNs) in Drosophila, which function as a predictive CDC in other insects. Both AHN pairs receive input primarily from a partially overlapping population of descending neurons, especially from DNg02, which controls wing motor output. Using Ca2+ imaging and behavioral recordings, we show that AHN activation is correlated to flight behavior and precedes wing motion. Optogenetic activation of DNg02 is sufficient to activate AHNs, indicating that AHNs are activated by descending commands in advance of behavior and not as a consequence of sensory input. Downstream, each AHN pair targets predominantly non-overlapping networks, including those that process visual, auditory, and mechanosensory information, as well as networks controlling wing, haltere, and leg sensorimotor control. These results support the conclusion that the AHNs provide a predictive motor signal about wing motor state to mostly non-overlapping sensory and motor networks. Future work will determine how AHN signaling is driven by other descending neurons and interpreted by AHN downstream targets to maintain adaptive sensorimotor performance.
Collapse
Affiliation(s)
- Han S J Cheong
- Department of Biology, West Virginia University, Morgantown, WV 26505, USA; Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA; Zuckerman Institute, Columbia University, New York, NY 10027, USA
| | - Kaitlyn N Boone
- Department of Biology, West Virginia University, Morgantown, WV 26505, USA; Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Marryn M Bennett
- Department of Biology, West Virginia University, Morgantown, WV 26505, USA
| | - Farzaan Salman
- Department of Biology, West Virginia University, Morgantown, WV 26505, USA
| | - Jacob D Ralston
- Department of Biology, West Virginia University, Morgantown, WV 26505, USA
| | - Kaleb Hatch
- Department of Biology, West Virginia University, Morgantown, WV 26505, USA
| | - Raven F Allen
- Department of Biology, West Virginia University, Morgantown, WV 26505, USA
| | - Alec M Phelps
- Department of Biology, West Virginia University, Morgantown, WV 26505, USA
| | - Andrew P Cook
- Department of Biology, West Virginia University, Morgantown, WV 26505, USA
| | - Jasper S Phelps
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA; Swiss Federal Institute of Technology Lausanne, 1015 Lausanne, Switzerland
| | - Mert Erginkaya
- Champalimaud Research, Champalimaud Centre for the Unknown, Lisbon 1400-038, Portugal
| | - Wei-Chung A Lee
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Gwyneth M Card
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA; Zuckerman Institute, Columbia University, New York, NY 10027, USA
| | - Kevin C Daly
- Department of Biology, West Virginia University, Morgantown, WV 26505, USA; Department of Neuroscience, West Virginia University, Morgantown, WV 26505, USA
| | - Andrew M Dacks
- Department of Biology, West Virginia University, Morgantown, WV 26505, USA; Department of Neuroscience, West Virginia University, Morgantown, WV 26505, USA.
| |
Collapse
|
3
|
Jagannathan SR, Jeans T, Van De Poll MN, van Swinderen B. Multivariate classification of multichannel long-term electrophysiology data identifies different sleep stages in fruit flies. SCIENCE ADVANCES 2024; 10:eadj4399. [PMID: 38381836 PMCID: PMC10881036 DOI: 10.1126/sciadv.adj4399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 01/18/2024] [Indexed: 02/23/2024]
Abstract
Identifying different sleep stages in humans and other mammals has traditionally relied on electroencephalograms. Such an approach is not feasible in certain animals such as invertebrates, although these animals could also be sleeping in stages. Here, we perform long-term multichannel local field potential recordings in the brains of behaving flies undergoing spontaneous sleep bouts. We acquired consistent spatial recordings of local field potentials across multiple flies, allowing us to compare brain activity across awake and sleep periods. Using machine learning, we uncover distinct temporal stages of sleep and explore the associated spatial and spectral features across the fly brain. Further, we analyze the electrophysiological correlates of microbehaviors associated with certain sleep stages. We confirm the existence of a distinct sleep stage associated with rhythmic proboscis extensions and show that spectral features of this sleep-related behavior differ significantly from those associated with the same behavior during wakefulness, indicating a dissociation between behavior and the brain states wherein these behaviors reside.
Collapse
Affiliation(s)
- Sridhar R. Jagannathan
- Department of Psychology, University of Cambridge, Cambridge, UK
- Institute of Neurophysiology, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Travis Jeans
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD Australia
| | | | - Bruno van Swinderen
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD Australia
| |
Collapse
|
4
|
Cheong HSJ, Boone KN, Bennett MM, Salman F, Ralston JD, Hatch K, Allen RF, Phelps AM, Cook AP, Phelps JS, Erginkaya M, Lee WCA, Card GM, Daly KC, Dacks AM. Organization of an Ascending Circuit that Conveys Flight Motor State. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.07.544074. [PMID: 37333334 PMCID: PMC10274802 DOI: 10.1101/2023.06.07.544074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Natural behaviors are a coordinated symphony of motor acts which drive self-induced or reafferent sensory activation. Single sensors only signal presence and magnitude of a sensory cue; they cannot disambiguate exafferent (externally-induced) from reafferent sources. Nevertheless, animals readily differentiate between these sources of sensory signals to make appropriate decisions and initiate adaptive behavioral outcomes. This is mediated by predictive motor signaling mechanisms, which emanate from motor control pathways to sensory processing pathways, but how predictive motor signaling circuits function at the cellular and synaptic level is poorly understood. We use a variety of techniques, including connectomics from both male and female electron microscopy volumes, transcriptomics, neuroanatomical, physiological and behavioral approaches to resolve the network architecture of two pairs of ascending histaminergic neurons (AHNs), which putatively provide predictive motor signals to several sensory and motor neuropil. Both AHN pairs receive input primarily from an overlapping population of descending neurons, many of which drive wing motor output. The two AHN pairs target almost exclusively non-overlapping downstream neural networks including those that process visual, auditory and mechanosensory information as well as networks coordinating wing, haltere, and leg motor output. These results support the conclusion that the AHN pairs multi-task, integrating a large amount of common input, then tile their output in the brain, providing predictive motor signals to non-overlapping sensory networks affecting motor control both directly and indirectly.
Collapse
Affiliation(s)
- Han S. J. Cheong
- Department of Biology, West Virginia University, Morgantown, WV 26505, United States of America
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, United States of America
| | - Kaitlyn N. Boone
- Department of Biology, West Virginia University, Morgantown, WV 26505, United States of America
| | - Marryn M. Bennett
- Department of Biology, West Virginia University, Morgantown, WV 26505, United States of America
| | - Farzaan Salman
- Department of Biology, West Virginia University, Morgantown, WV 26505, United States of America
| | - Jacob D. Ralston
- Department of Biology, West Virginia University, Morgantown, WV 26505, United States of America
| | - Kaleb Hatch
- Department of Biology, West Virginia University, Morgantown, WV 26505, United States of America
| | - Raven F. Allen
- Department of Biology, West Virginia University, Morgantown, WV 26505, United States of America
| | - Alec M. Phelps
- Department of Biology, West Virginia University, Morgantown, WV 26505, United States of America
| | - Andrew P. Cook
- Department of Biology, West Virginia University, Morgantown, WV 26505, United States of America
| | - Jasper S. Phelps
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, United States of America
| | - Mert Erginkaya
- Champalimaud Research, Champalimaud Centre for the Unknown, Lisbon, 1400-038, Portugal
| | - Wei-Chung A. Lee
- F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, United States of America
| | - Gwyneth M. Card
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, United States of America
- Zuckerman Institute, Columbia University, New York, NY 10027, United States of America
| | - Kevin C. Daly
- Department of Biology, West Virginia University, Morgantown, WV 26505, United States of America
- Department of Neuroscience, West Virginia University, Morgantown, WV 26505, United States of America
| | - Andrew M. Dacks
- Department of Biology, West Virginia University, Morgantown, WV 26505, United States of America
- Department of Neuroscience, West Virginia University, Morgantown, WV 26505, United States of America
| |
Collapse
|
5
|
Brown E, Worden K, Li Y, Masek P, Keene AC. Innate and Conditioned Taste Processing in Drosophila. Cold Spring Harb Protoc 2023; 2023:pdb.top107864. [PMID: 36787965 PMCID: PMC10750968 DOI: 10.1101/pdb.top107864] [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: 02/16/2023]
Abstract
Peripheral detection of tastants allows animals to detect the dietary value of food and its potential toxicity. Many tastants such as sugars and fats elicit reflexive appetitive responses, whereas other foods such as quinine induce aversion. The relative value of food can change in accordance with an animal's internal state and prior experience. Understanding the neural and genetic bases for the detection and response to tastants, as well as how these behaviors change with experience, is central to sensory neuroscience. The presentation of attractive tastants to the proboscis or legs of the fruit fly Drosophila melanogaster induces a robust and reflexive proboscis-extension response (PER). This quantifiable response can be used to study the receptors underlying taste detection, the neural circuits involved in sensory processing, and the musculature required for a simple feeding behavior. Furthermore, we have developed a memory assay pairing appetitive and bitter tastants, resulting in aversive taste conditioning, in which the PER response to attractive tastants is diminished. Unlike many memory assays, this assay does not require specialized equipment and can be readily implemented in teaching and research laboratories. Here, we introduce protocols for studying the PER feeding response and aversive taste memory in Drosophila.
Collapse
Affiliation(s)
- Elizabeth Brown
- Department of Biology, Texas A&M University, College Station, Texas 77843, USA
| | - Kurtresha Worden
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, California 94720, USA
| | - Yuanyuan Li
- Department of Biological Sciences, Binghamton University, Binghamton, New York 13902, USA
| | - Pavel Masek
- Department of Biological Sciences, Binghamton University, Binghamton, New York 13902, USA
| | - Alex C Keene
- Department of Biology, Texas A&M University, College Station, Texas 77843, USA
| |
Collapse
|
6
|
Brown E, Worden K, Li Y, Masek P, Keene AC. Measurement of Taste Memory in Drosophila. Cold Spring Harb Protoc 2023; 2023:pdb.prot108093. [PMID: 36787963 PMCID: PMC10750969 DOI: 10.1101/pdb.prot108093] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
The ability to modify behavior as a result of previous experience allows an organism to adapt to changes in its environment. Even innate behaviors, like feeding initiation, can change if previously associated with a noxious stimulus. Here, we describe a taste memory assay pairing appetitive and bitter tastants, resulting in aversive taste conditioning. By training a fly to associate sweet sucrose applied to the tarsus with bitter quinine applied to the proboscis, flies quickly learn to suppress the reflexive proboscis extension to sucrose, providing a bioassay for behavioral and molecular plasticity. This single-fly taste memory assay may be applied to adult Drosophila of any genetic background and allows for interrogation of the neural circuitry and molecular processes encoding memories while simultaneously measuring behavior. Unlike many other memory assays, this system requires few custom components, and therefore can be easily established in laboratories with minimal expertise in the study of fly behavior.
Collapse
Affiliation(s)
- Elizabeth Brown
- Department of Biology, Texas A&M University, College Station, Texas 77843, USA
| | - Kurtresha Worden
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, California 94720, USA
| | - Yuanyuan Li
- Department of Biological Sciences, Binghamton University, Binghamton, New York 13902, USA
| | - Pavel Masek
- Department of Biological Sciences, Binghamton University, Binghamton, New York 13902, USA
| | - Alex C Keene
- Department of Biology, Texas A&M University, College Station, Texas 77843, USA
| |
Collapse
|
7
|
Deere JU, Sarkissian AA, Yang M, Uttley HA, Martinez Santana N, Nguyen L, Ravi K, Devineni AV. Selective integration of diverse taste inputs within a single taste modality. eLife 2023; 12:e84856. [PMID: 36692370 PMCID: PMC9873257 DOI: 10.7554/elife.84856] [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: 11/11/2022] [Accepted: 01/10/2023] [Indexed: 01/25/2023] Open
Abstract
A fundamental question in sensory processing is how different channels of sensory input are processed to regulate behavior. Different input channels may converge onto common downstream pathways to drive the same behaviors, or they may activate separate pathways to regulate distinct behaviors. We investigated this question in the Drosophila bitter taste system, which contains diverse bitter-sensing cells residing in different taste organs. First, we optogenetically activated subsets of bitter neurons within each organ. These subsets elicited broad and highly overlapping behavioral effects, suggesting that they converge onto common downstream pathways, but we also observed behavioral differences that argue for biased convergence. Consistent with these results, transsynaptic tracing revealed that bitter neurons in different organs connect to overlapping downstream pathways with biased connectivity. We investigated taste processing in one type of downstream bitter neuron that projects to the higher brain. These neurons integrate input from multiple organs and regulate specific taste-related behaviors. We then traced downstream circuits, providing the first glimpse into taste processing in the higher brain. Together, these results reveal that different bitter inputs are selectively integrated early in the circuit, enabling the pooling of information, while the circuit then diverges into multiple pathways that may have different roles.
Collapse
Affiliation(s)
- Julia U Deere
- Zuckerman Mind Brain Behavior Institute, Columbia UniversityNew YorkUnited States
| | | | - Meifeng Yang
- Department of Biology, Emory UniversityAtlantaUnited States
| | - Hannah A Uttley
- Zuckerman Mind Brain Behavior Institute, Columbia UniversityNew YorkUnited States
| | | | - Lam Nguyen
- Department of Biology, Emory UniversityAtlantaUnited States
| | - Kaushiki Ravi
- Department of Biology, Emory UniversityAtlantaUnited States
| | - Anita V Devineni
- Zuckerman Mind Brain Behavior Institute, Columbia UniversityNew YorkUnited States
- Neuroscience Graduate Program, Emory UniversityAtlantaUnited States
- Department of Biology, Emory UniversityAtlantaUnited States
| |
Collapse
|
8
|
Zhao Y, Duan J, Han Z, Engström Y, Hartenstein V. Identification of a GABAergic neuroblast lineage modulating sweet and bitter taste sensitivity. Curr Biol 2022; 32:5354-5363.e3. [PMID: 36347251 PMCID: PMC10728805 DOI: 10.1016/j.cub.2022.10.029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 06/16/2022] [Accepted: 10/14/2022] [Indexed: 11/09/2022]
Abstract
In Drosophila melanogaster, processing of gustatory information and controlling feeding behavior are executed by neural circuits located in the subesophageal zone (SEZ) of the brain.1 Gustatory receptor neurons (GRNs) project their axons in the primary gustatory center (PGC), which is located in the SEZ.1,2,3,4 To address the function of the PGC, we need detailed information about the different classes of gustatory interneurons that frame the PGC. In this work, we screened large collections of driver lines for SEZ interneuron-specific labeling and subsequently used candidate lines to access the SEZ neuroblast lineages. We converted 130 Gal4 lines to LexA drivers and carried out functional screening using calcium imaging. We found one neuroblast lineage, TRdm, whose neurons responded to both sweet and bitter tastants, and formed green fluorescent protein (GFP) reconstitution across synaptic partners (GRASP)-positive synapses with sweet sensory neurons. TRdm neurons express the inhibitory transmitter GABA, and silencing these neurons increases appetitive feeding behavior. These results demonstrate that TRdm generates a class of inhibitory local neurons that control taste sensitivity in Drosophila.
Collapse
Affiliation(s)
- Yunpo Zhao
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden; Biozentrum, University of Basel, 4056 Basel, Switzerland; Center for Precision Disease Modeling, University of Maryland School of Medicine, Baltimore 21201, USA.
| | - Jianli Duan
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden; Center for Precision Disease Modeling, University of Maryland School of Medicine, Baltimore 21201, USA
| | - Zhe Han
- Center for Precision Disease Modeling, University of Maryland School of Medicine, Baltimore 21201, USA
| | - Ylva Engström
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden
| | - Volker Hartenstein
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles 90095-1606, USA.
| |
Collapse
|
9
|
Vijayan V, Wang Z, Chandra V, Chakravorty A, Li R, Sarbanes SL, Akhlaghpour H, Maimon G. An internal expectation guides Drosophila egg-laying decisions. SCIENCE ADVANCES 2022; 8:eabn3852. [PMID: 36306348 PMCID: PMC9616500 DOI: 10.1126/sciadv.abn3852] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
To better understand how animals make ethologically relevant decisions, we studied egg-laying substrate choice in Drosophila. We found that flies dynamically increase or decrease their egg-laying rates while exploring substrates so as to target eggs to the best, recently visited option. Visiting the best option typically yielded inhibition of egg laying on other substrates for many minutes. Our data support a model in which flies compare the current substrate's value with an internally constructed expectation on the value of available options to regulate the likelihood of laying an egg. We show that dopamine neuron activity is critical for learning and/or expressing this expectation, similar to its role in certain tasks in vertebrates. Integrating sensory experiences over minutes to generate an estimate of the quality of available options allows flies to use a dynamic reference point for judging the current substrate and might be a general way in which decisions are made.
Collapse
|
10
|
Snell NJ, Fisher JD, Hartmann GG, Zolyomi B, Talay M, Barnea G. Complex representation of taste quality by second-order gustatory neurons in Drosophila. Curr Biol 2022; 32:3758-3772.e4. [PMID: 35973432 PMCID: PMC9474709 DOI: 10.1016/j.cub.2022.07.048] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 04/08/2022] [Accepted: 07/19/2022] [Indexed: 01/24/2023]
Abstract
Sweet and bitter compounds excite different sensory cells and drive opposing behaviors. However, it remains unclear how sweet and bitter tastes are represented by the neural circuits linking sensation to behavior. To investigate this question in Drosophila, we devised trans-Tango(activity), a strategy for calcium imaging of second-order gustatory projection neurons based on trans-Tango, a genetic transsynaptic tracing technique. We found spatial overlap between the projection neuron populations activated by sweet and bitter tastants. The spatial representation of bitter tastants in the projection neurons was consistent, while that of sweet tastants was heterogeneous. Furthermore, we discovered that bitter tastants evoke responses in the gustatory receptor neurons and projection neurons upon both stimulus onset and offset and that bitter offset and sweet onset excite overlapping second-order projections. These findings demonstrate an unexpected complexity in the representation of sweet and bitter tastants by second-order neurons of the gustatory circuit.
Collapse
Affiliation(s)
- Nathaniel J Snell
- Department of Neuroscience, Division of Biology and Medicine, Brown University, Providence, RI 02912, USA; The Robert J. and Nancy D. Carney Institute for Brain Science, Brown University, Providence, RI 02912, USA
| | - John D Fisher
- Department of Neuroscience, Division of Biology and Medicine, Brown University, Providence, RI 02912, USA; The Robert J. and Nancy D. Carney Institute for Brain Science, Brown University, Providence, RI 02912, USA
| | - Griffin G Hartmann
- Department of Neuroscience, Division of Biology and Medicine, Brown University, Providence, RI 02912, USA; The Robert J. and Nancy D. Carney Institute for Brain Science, Brown University, Providence, RI 02912, USA
| | - Bence Zolyomi
- Department of Neuroscience, Division of Biology and Medicine, Brown University, Providence, RI 02912, USA; The Robert J. and Nancy D. Carney Institute for Brain Science, Brown University, Providence, RI 02912, USA
| | - Mustafa Talay
- Department of Neuroscience, Division of Biology and Medicine, Brown University, Providence, RI 02912, USA; The Robert J. and Nancy D. Carney Institute for Brain Science, Brown University, Providence, RI 02912, USA
| | - Gilad Barnea
- Department of Neuroscience, Division of Biology and Medicine, Brown University, Providence, RI 02912, USA; The Robert J. and Nancy D. Carney Institute for Brain Science, Brown University, Providence, RI 02912, USA.
| |
Collapse
|
11
|
The neuronal logic of how internal states control food choice. Nature 2022; 607:747-755. [DOI: 10.1038/s41586-022-04909-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 05/25/2022] [Indexed: 11/08/2022]
|
12
|
Sun LL, Liu XL, Wang YN, Berg BG, Xie GY, Chen WB, Liu Y, Wang GR, Zhao XC, Tang QB. Neuronal architecture and functional mapping of the taste center of larval Helicoverpa armigera (Lepidoptera: Noctuidae). INSECT SCIENCE 2022; 29:730-748. [PMID: 34427391 DOI: 10.1111/1744-7917.12965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 08/17/2021] [Accepted: 08/19/2021] [Indexed: 06/13/2023]
Abstract
The sense of taste plays a crucial role in herbivorous insects by discriminating nutrients from complex plant metabolic compounds. The peripheral coding of taste has been thoroughly studied in many insect species, but the central gustatory pathways are poorly described. In the present study, we characterized single neurons in the gnathal ganglion of Helicoverpa armigera larvae using the intracellular recording/staining technique. We identified different types of neurons, including sensory neurons, interneurons, and motor neurons. The morphologies of these neurons were largely diverse and their arborizations seemingly covered the whole gnathal ganglion. The representation of the single neurons responding to the relevant stimuli of sweet and bitter cues showed no distinct patterns in the gnathal ganglion. We postulate that taste signals may be processed in a manner consistent with the principle of population coding in the gnathal ganglion of H. armigera larvae.
Collapse
Affiliation(s)
- Long-Long Sun
- Department of Entomology, College of Plant Protection, Henan Agricultural University, Zhengzhou, 450002, China
| | - Xiao-Lan Liu
- Department of Entomology, College of Plant Protection, Henan Agricultural University, Zhengzhou, 450002, China
| | - Ya-Nan Wang
- Department of Entomology, College of Plant Protection, Henan Agricultural University, Zhengzhou, 450002, China
| | - Bente G Berg
- Chemosensory laboratory, Department of Psychology, Norwegian University of Science and Technology, Trondheim, 7489, Norway
| | - Gui-Ying Xie
- Department of Entomology, College of Plant Protection, Henan Agricultural University, Zhengzhou, 450002, China
| | - Wen-Bo Chen
- Department of Entomology, College of Plant Protection, Henan Agricultural University, Zhengzhou, 450002, China
| | - Yang Liu
- State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Gui-Rong Wang
- State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Xin-Cheng Zhao
- Department of Entomology, College of Plant Protection, Henan Agricultural University, Zhengzhou, 450002, China
| | - Qing-Bo Tang
- Department of Entomology, College of Plant Protection, Henan Agricultural University, Zhengzhou, 450002, China
| |
Collapse
|
13
|
A functional division of Drosophila sweet taste neurons that is value-based and task-specific. Proc Natl Acad Sci U S A 2022; 119:2110158119. [PMID: 35031566 PMCID: PMC8784143 DOI: 10.1073/pnas.2110158119] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/07/2021] [Indexed: 11/18/2022] Open
Abstract
Sucrose is an attractive feeding substance and a positive reinforcer for Drosophila But Drosophila females have been shown to robustly reject a sucrose-containing option for egg-laying when given a choice between a plain and a sucrose-containing option in specific contexts. How the sweet taste system of Drosophila promotes context-dependent devaluation of an egg-laying option that contains sucrose, an otherwise highly appetitive tastant, is unknown. Here, we report that devaluation of sweetness/sucrose for egg-laying is executed by a sensory pathway recruited specifically by the sweet neurons on the legs of Drosophila First, silencing just the leg sweet neurons caused acceptance of the sucrose option in a sucrose versus plain decision, whereas expressing the channelrhodopsin CsChrimson in them caused rejection of a plain option that was "baited" with light over another that was not. Analogous bidirectional manipulations of other sweet neurons did not produce these effects. Second, circuit tracing revealed that the leg sweet neurons receive different presynaptic neuromodulations compared to some other sweet neurons and were the only ones with postsynaptic partners that projected prominently to the superior lateral protocerebrum (SLP) in the brain. Third, silencing one specific SLP-projecting postsynaptic partner of the leg sweet neurons reduced sucrose rejection, whereas expressing CsChrimson in it promoted rejection of a light-baited option during egg-laying. These results uncover that the Drosophila sweet taste system exhibits a functional division that is value-based and task-specific, challenging the conventional view that the system adheres to a simple labeled-line coding scheme.
Collapse
|
14
|
Yao Z, Scott K. Serotonergic neurons translate taste detection into internal nutrient regulation. Neuron 2022; 110:1036-1050.e7. [PMID: 35051377 DOI: 10.1016/j.neuron.2021.12.028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 09/26/2021] [Accepted: 12/16/2021] [Indexed: 12/20/2022]
Abstract
The nervous and endocrine systems coordinately monitor and regulate nutrient availability to maintain energy homeostasis. Sensory detection of food regulates internal nutrient availability in a manner that anticipates food intake, but sensory pathways that promote anticipatory physiological changes remain unclear. Here, we identify serotonergic (5-HT) neurons as critical mediators that transform gustatory detection by sensory neurons into the activation of insulin-producing cells and enteric neurons in Drosophila. One class of 5-HT neurons responds to gustatory detection of sugars, excites insulin-producing cells, and limits consumption, suggesting that they anticipate increased nutrient levels and prevent overconsumption. A second class of 5-HT neurons responds to gustatory detection of bitter compounds and activates enteric neurons to promote gastric motility, likely to stimulate digestion and increase circulating nutrients upon food rejection. These studies demonstrate that 5-HT neurons relay acute gustatory detection to divergent pathways for longer-term stabilization of circulating nutrients.
Collapse
Affiliation(s)
- Zepeng Yao
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA.
| | - Kristin Scott
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA.
| |
Collapse
|
15
|
Abstract
Bitter taste signals a potentially toxic food that should be avoided. A new study shows that taste neurons in Drosophila produce distinct responses after a bitter sip. A bitter aftertaste may help the fly make wise food choices.
Collapse
Affiliation(s)
- Hojoon Lee
- Department of Neurobiology, Northwestern University, Evanston, IL 60208, USA.
| | - Michael H Alpert
- Department of Neurobiology, Northwestern University, Evanston, IL 60208, USA
| | - Marco Gallio
- Department of Neurobiology, Northwestern University, Evanston, IL 60208, USA.
| |
Collapse
|
16
|
Devineni AV, Deere JU, Sun B, Axel R. Individual bitter-sensing neurons in Drosophila exhibit both ON and OFF responses that influence synaptic plasticity. Curr Biol 2021; 31:5533-5546.e7. [PMID: 34731675 DOI: 10.1016/j.cub.2021.10.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 09/04/2021] [Accepted: 10/08/2021] [Indexed: 01/07/2023]
Abstract
The brain generates internal representations that translate sensory stimuli into appropriate behavior. In the taste system, different tastes activate distinct populations of sensory neurons. We investigated the temporal properties of taste responses in Drosophila and discovered that different types of taste sensory neurons show striking differences in their response dynamics. Strong responses to stimulus onset (ON responses) and offset (OFF responses) were observed in bitter-sensing neurons in the labellum, whereas bitter neurons in the leg and other classes of labellar taste neurons showed only an ON response. Individual labellar bitter neurons generate both ON and OFF responses through a cell-intrinsic mechanism that requires canonical bitter receptors. A single receptor complex likely generates both ON and OFF responses to a given bitter ligand. These ON and OFF responses in the periphery are propagated to dopaminergic neurons that mediate aversive learning, and the presence of the OFF response impacts synaptic plasticity when bitter is used as a reinforcement cue. These studies reveal previously unknown features of taste responses that impact neural circuit function and may be important for behavior. Moreover, these studies show that OFF responses can dramatically influence timing-based synaptic plasticity, which is thought to underlie associative learning.
Collapse
Affiliation(s)
- Anita V Devineni
- Zuckerman Mind Brain Behavior Institute, Columbia University, 3227 Broadway, New York, NY 10027, USA.
| | - Julia U Deere
- Zuckerman Mind Brain Behavior Institute, Columbia University, 3227 Broadway, New York, NY 10027, USA
| | - Bei Sun
- Zuckerman Mind Brain Behavior Institute, Columbia University, 3227 Broadway, New York, NY 10027, USA
| | - Richard Axel
- Zuckerman Mind Brain Behavior Institute, Columbia University, 3227 Broadway, New York, NY 10027, USA; Howard Hughes Medical Institute, Columbia University, New York, NY 10032, USA.
| |
Collapse
|
17
|
Sterne GR, Otsuna H, Dickson BJ, Scott K. Classification and genetic targeting of cell types in the primary taste and premotor center of the adult Drosophila brain. eLife 2021; 10:e71679. [PMID: 34473057 PMCID: PMC8445619 DOI: 10.7554/elife.71679] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Accepted: 09/01/2021] [Indexed: 12/29/2022] Open
Abstract
Neural circuits carry out complex computations that allow animals to evaluate food, select mates, move toward attractive stimuli, and move away from threats. In insects, the subesophageal zone (SEZ) is a brain region that receives gustatory, pheromonal, and mechanosensory inputs and contributes to the control of diverse behaviors, including feeding, grooming, and locomotion. Despite its importance in sensorimotor transformations, the study of SEZ circuits has been hindered by limited knowledge of the underlying diversity of SEZ neurons. Here, we generate a collection of split-GAL4 lines that provides precise genetic targeting of 138 different SEZ cell types in adult Drosophila melanogaster, comprising approximately one third of all SEZ neurons. We characterize the single-cell anatomy of these neurons and find that they cluster by morphology into six supergroups that organize the SEZ into discrete anatomical domains. We find that the majority of local SEZ interneurons are not classically polarized, suggesting rich local processing, whereas SEZ projection neurons tend to be classically polarized, conveying information to a limited number of higher brain regions. This study provides insight into the anatomical organization of the SEZ and generates resources that will facilitate further study of SEZ neurons and their contributions to sensory processing and behavior.
Collapse
Affiliation(s)
- Gabriella R Sterne
- University of California BerkeleyBerkeleyUnited States
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Hideo Otsuna
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Barry J Dickson
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
- Queensland Brain Institute, University of QueenslandQueenslandAustralia
| | - Kristin Scott
- University of California BerkeleyBerkeleyUnited States
| |
Collapse
|
18
|
Sareen PF, McCurdy LY, Nitabach MN. A neuronal ensemble encoding adaptive choice during sensory conflict in Drosophila. Nat Commun 2021; 12:4131. [PMID: 34226544 PMCID: PMC8257655 DOI: 10.1038/s41467-021-24423-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 06/18/2021] [Indexed: 01/02/2023] Open
Abstract
Feeding decisions are fundamental to survival, and decision making is often disrupted in disease. Here, we show that neural activity in a small population of neurons projecting to the fan-shaped body higher-order central brain region of Drosophila represents food choice during sensory conflict. We found that food deprived flies made tradeoffs between appetitive and aversive values of food. We identified an upstream neuropeptidergic and dopaminergic network that relays internal state and other decision-relevant information to a specific subset of fan-shaped body neurons. These neurons were strongly inhibited by the taste of the rejected food choice, suggesting that they encode behavioral food choice. Our findings reveal that fan-shaped body taste responses to food choices are determined not only by taste quality, but also by previous experience (including choice outcome) and hunger state, which are integrated in the fan-shaped body to encode the decision before relay to downstream motor circuits for behavioral implementation.
Collapse
Affiliation(s)
- Preeti F Sareen
- Department of Cellular and Molecular Physiology, Yale University, New Haven, CT, USA
| | - Li Yan McCurdy
- Department of Cellular and Molecular Physiology, Yale University, New Haven, CT, USA
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT, USA
| | - Michael N Nitabach
- Department of Cellular and Molecular Physiology, Yale University, New Haven, CT, USA.
- Department of Genetics, Yale University, New Haven, CT, USA.
- Department of Neuroscience, Yale University, New Haven, CT, USA.
| |
Collapse
|
19
|
Lau CKS, Jelen M, Gordon MD. A closed-loop optogenetic screen for neurons controlling feeding in Drosophila. G3-GENES GENOMES GENETICS 2021; 11:6170659. [PMID: 33714999 PMCID: PMC8104954 DOI: 10.1093/g3journal/jkab073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 03/03/2021] [Indexed: 11/14/2022]
Abstract
Feeding is an essential part of animal life that is greatly impacted by the sense of taste. Although the characterization of taste-detection at the periphery has been extensive, higher order taste and feeding circuits are still being elucidated. Here, we use an automated closed-loop optogenetic activation screen to detect novel taste and feeding neurons in Drosophila melanogaster. Out of 122 Janelia FlyLight Project GAL4 lines preselected based on expression pattern, we identify six lines that acutely promote feeding and 35 lines that inhibit it. As proof of principle, we follow up on R70C07-GAL4, which labels neurons that strongly inhibit feeding. Using split-GAL4 lines to isolate subsets of the R70C07-GAL4 population, we find both appetitive and aversive neurons. Furthermore, we show that R70C07-GAL4 labels putative second-order taste interneurons that contact both sweet and bitter sensory neurons. These results serve as a resource for further functional dissection of fly feeding circuits.
Collapse
Affiliation(s)
- Celia K S Lau
- Department of Zoology and Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Meghan Jelen
- Department of Zoology and Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Michael D Gordon
- Department of Zoology and Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| |
Collapse
|
20
|
Kymre JH, Berge CN, Chu X, Ian E, Berg BG. Antennal-lobe neurons in the moth Helicoverpa armigera: Morphological features of projection neurons, local interneurons, and centrifugal neurons. J Comp Neurol 2021; 529:1516-1540. [PMID: 32949023 PMCID: PMC8048870 DOI: 10.1002/cne.25034] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 09/02/2020] [Accepted: 09/07/2020] [Indexed: 01/11/2023]
Abstract
The relatively large primary olfactory center of the insect brain, the antennal lobe (AL), contains several heterogeneous neuronal types. These include projection neurons (PNs), providing olfactory information to higher‐order neuropils via parallel pathways, and local interneurons (LNs), which provide lateral processing within the AL. In addition, various types of centrifugal neurons (CNs) offer top‐down modulation onto the other AL neurons. By performing iontophoretic intracellular staining, we collected a large number of AL neurons in the moth, Helicoverpa armigera, to examine the distinct morphological features of PNs, LNs, and CNs. We characterize 190 AL neurons. These were allocated to 25 distinct neuronal types or sub‐types, which were reconstructed and placed into a reference brain. In addition to six PN types comprising 15 sub‐types, three LN and seven CN types were identified. High‐resolution confocal images allowed us to analyze AL innervations of the various reported neurons, which demonstrated that all PNs innervating ventroposterior glomeruli contact a protocerebral neuropil rarely targeted by other PNs, that is the posteriorlateral protocerebrum. We also discuss the functional roles of the distinct CNs, which included several previously uncharacterized types, likely involved in computations spanning from multisensory processing to olfactory feedback signalization into the AL.
Collapse
Affiliation(s)
- Jonas Hansen Kymre
- Chemosensory lab, Department of Psychology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Christoffer Nerland Berge
- Chemosensory lab, Department of Psychology, Norwegian University of Science and Technology, Trondheim, Norway.,Laboratory for Neural Computation, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Xi Chu
- Chemosensory lab, Department of Psychology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Elena Ian
- Chemosensory lab, Department of Psychology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Bente G Berg
- Chemosensory lab, Department of Psychology, Norwegian University of Science and Technology, Trondheim, Norway
| |
Collapse
|
21
|
Nojima T, Rings A, Allen AM, Otto N, Verschut TA, Billeter JC, Neville MC, Goodwin SF. A sex-specific switch between visual and olfactory inputs underlies adaptive sex differences in behavior. Curr Biol 2021; 31:1175-1191.e6. [PMID: 33508219 PMCID: PMC7987718 DOI: 10.1016/j.cub.2020.12.047] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 12/15/2020] [Accepted: 12/24/2020] [Indexed: 01/05/2023]
Abstract
Although males and females largely share the same genome and nervous system, they differ profoundly in reproductive investments and require distinct behavioral, morphological, and physiological adaptations. How can the nervous system, while bound by both developmental and biophysical constraints, produce these sex differences in behavior? Here, we uncover a novel dimorphism in Drosophila melanogaster that allows deployment of completely different behavioral repertoires in males and females with minimum changes to circuit architecture. Sexual differentiation of only a small number of higher order neurons in the brain leads to a change in connectivity related to the primary reproductive needs of both sexes-courtship pursuit in males and communal oviposition in females. This study explains how an apparently similar brain generates distinct behavioral repertoires in the two sexes and presents a fundamental principle of neural circuit organization that may be extended to other species.
Collapse
Affiliation(s)
- Tetsuya Nojima
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford OX1 3SR, UK
| | - Annika Rings
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford OX1 3SR, UK
| | - Aaron M Allen
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford OX1 3SR, UK
| | - Nils Otto
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford OX1 3SR, UK
| | - Thomas A Verschut
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, the Netherlands
| | - Jean-Christophe Billeter
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, the Netherlands
| | - Megan C Neville
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford OX1 3SR, UK.
| | - Stephen F Goodwin
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford OX1 3SR, UK.
| |
Collapse
|
22
|
Siju KP, De Backer JF, Grunwald Kadow IC. Dopamine modulation of sensory processing and adaptive behavior in flies. Cell Tissue Res 2021; 383:207-225. [PMID: 33515291 PMCID: PMC7873103 DOI: 10.1007/s00441-020-03371-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 11/26/2020] [Indexed: 12/31/2022]
Abstract
Behavioral flexibility for appropriate action selection is an advantage when animals are faced with decisions that will determine their survival or death. In order to arrive at the right decision, animals evaluate information from their external environment, internal state, and past experiences. How these different signals are integrated and modulated in the brain, and how context- and state-dependent behavioral decisions are controlled are poorly understood questions. Studying the molecules that help convey and integrate such information in neural circuits is an important way to approach these questions. Many years of work in different model organisms have shown that dopamine is a critical neuromodulator for (reward based) associative learning. However, recent findings in vertebrates and invertebrates have demonstrated the complexity and heterogeneity of dopaminergic neuron populations and their functional implications in many adaptive behaviors important for survival. For example, dopaminergic neurons can integrate external sensory information, internal and behavioral states, and learned experience in the decision making circuitry. Several recent advances in methodologies and the availability of a synaptic level connectome of the whole-brain circuitry of Drosophila melanogaster make the fly an attractive system to study the roles of dopamine in decision making and state-dependent behavior. In particular, a learning and memory center-the mushroom body-is richly innervated by dopaminergic neurons that enable it to integrate multi-modal information according to state and context, and to modulate decision-making and behavior.
Collapse
Affiliation(s)
- K. P. Siju
- School of Life Sciences, Department of Molecular Life Sciences, Technical University of Munich, 85354 Freising, Germany
| | - Jean-Francois De Backer
- School of Life Sciences, Department of Molecular Life Sciences, Technical University of Munich, 85354 Freising, Germany
| | - Ilona C. Grunwald Kadow
- School of Life Sciences, Department of Molecular Life Sciences, Technical University of Munich, 85354 Freising, Germany
| |
Collapse
|
23
|
Das Chakraborty S, Sachse S. Olfactory processing in the lateral horn of Drosophila. Cell Tissue Res 2021; 383:113-123. [PMID: 33475851 PMCID: PMC7873099 DOI: 10.1007/s00441-020-03392-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 12/10/2020] [Indexed: 11/24/2022]
Abstract
Sensing olfactory signals in the environment represents a crucial and significant task of sensory systems in almost all organisms to facilitate survival and reproduction. Notably, the olfactory system of diverse animal phyla shares astonishingly many fundamental principles with regard to anatomical and functional properties. Binding of odor ligands by chemosensory receptors present in the olfactory peripheral organs leads to a neuronal activity that is conveyed to first and higher-order brain centers leading to a subsequent odor-guided behavioral decision. One of the key centers for integrating and processing innate olfactory behavior is the lateral horn (LH) of the protocerebrum in insects. In recent years the LH of Drosophila has garnered increasing attention and many studies have been dedicated to elucidate its circuitry. In this review we will summarize the recent advances in mapping and characterizing LH-specific cell types, their functional properties with respect to odor tuning, their neurotransmitter profiles, their connectivity to pre-synaptic and post-synaptic partner neurons as well as their impact for olfactory behavior as known so far.
Collapse
Affiliation(s)
- Sudeshna Das Chakraborty
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Hans-Knoell-Str. 8, 07745, Jena, Germany
| | - Silke Sachse
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Hans-Knoell-Str. 8, 07745, Jena, Germany.
| |
Collapse
|
24
|
How Bacteria Impact Host Nervous System and Behaviors: Lessons from Flies and Worms. Trends Neurosci 2020; 43:998-1010. [PMID: 33051027 DOI: 10.1016/j.tins.2020.09.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 09/01/2020] [Accepted: 09/16/2020] [Indexed: 12/12/2022]
Abstract
Behavior is the neuronally controlled, voluntary or involuntary response of an organism to its environment. An increasing body of evidence indicates that microbes, which live closely associated with animals or in their immediate surroundings, significantly influence animals' behavior. The extreme complexity of the nervous system of animals, combined with the extraordinary microbial diversity, are two major obstacles to understand, at the molecular level, how microbes modulate animal behavior. In this review, we discuss recent advances in dissecting the impact that bacteria have on the nervous system of two genetically tractable invertebrate models, Drosophila melanogaster and Caenorhabditis elegans.
Collapse
|
25
|
Melnattur K, Zhang B, Shaw PJ. Disrupting flight increases sleep and identifies a novel sleep-promoting pathway in Drosophila. SCIENCE ADVANCES 2020; 6:eaaz2166. [PMID: 32494708 PMCID: PMC7209998 DOI: 10.1126/sciadv.aaz2166] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 02/25/2020] [Indexed: 06/06/2023]
Abstract
Sleep is plastic and is influenced by ecological factors and environmental changes. The mechanisms underlying sleep plasticity are not well understood. We show that manipulations that impair flight in Drosophila increase sleep as a form of sleep plasticity. We disrupted flight by blocking the wing-expansion program, genetically disrupting flight, and by mechanical wing perturbations. We defined a new sleep regulatory circuit starting with specific wing sensory neurons, their target projection neurons in the ventral nerve cord, and the neurons they connect to in the central brain. In addition, we identified a critical neuropeptide (burs) and its receptor (rickets) that link wing expansion and sleep. Disrupting flight activates these sleep-promoting projection neurons, as indicated by increased cytosolic calcium levels, and stably increases the number of synapses in their axonal projections. These data reveal an unexpected role for flight in regulating sleep and provide new insight into how sensory processing controls sleep need.
Collapse
Affiliation(s)
- K. Melnattur
- Department of Neuroscience, Washington University School of Medicine, Campus Box 8108, 660 South Euclid Avenue, St. Louis, MO 63110, USA
| | - B. Zhang
- Division of Biological Sciences, University of Missouri, Columbia, MO 65211, USA
| | - P. J. Shaw
- Department of Neuroscience, Washington University School of Medicine, Campus Box 8108, 660 South Euclid Avenue, St. Louis, MO 63110, USA
| |
Collapse
|
26
|
Allen AM, Neville MC, Birtles S, Croset V, Treiber CD, Waddell S, Goodwin SF. A single-cell transcriptomic atlas of the adult Drosophila ventral nerve cord. eLife 2020; 9:e54074. [PMID: 32314735 PMCID: PMC7173974 DOI: 10.7554/elife.54074] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Accepted: 04/03/2020] [Indexed: 02/07/2023] Open
Abstract
The Drosophila ventral nerve cord (VNC) receives and processes descending signals from the brain to produce a variety of coordinated locomotor outputs. It also integrates sensory information from the periphery and sends ascending signals to the brain. We used single-cell transcriptomics to generate an unbiased classification of cellular diversity in the VNC of five-day old adult flies. We produced an atlas of 26,000 high-quality cells, representing more than 100 transcriptionally distinct cell types. The predominant gene signatures defining neuronal cell types reflect shared developmental histories based on the neuroblast from which cells were derived, as well as their birth order. The relative position of cells along the anterior-posterior axis could also be assigned using adult Hox gene expression. This single-cell transcriptional atlas of the adult fly VNC will be a valuable resource for future studies of neurodevelopment and behavior.
Collapse
Affiliation(s)
- Aaron M Allen
- Centre for Neural Circuits and Behaviour, University of OxfordOxfordUnited Kingdom
| | - Megan C Neville
- Centre for Neural Circuits and Behaviour, University of OxfordOxfordUnited Kingdom
| | - Sebastian Birtles
- Centre for Neural Circuits and Behaviour, University of OxfordOxfordUnited Kingdom
| | - Vincent Croset
- Centre for Neural Circuits and Behaviour, University of OxfordOxfordUnited Kingdom
| | | | - Scott Waddell
- Centre for Neural Circuits and Behaviour, University of OxfordOxfordUnited Kingdom
| | - Stephen F Goodwin
- Centre for Neural Circuits and Behaviour, University of OxfordOxfordUnited Kingdom
| |
Collapse
|
27
|
Chia J, Scott K. Activation of specific mushroom body output neurons inhibits proboscis extension and sucrose consumption. PLoS One 2020; 15:e0223034. [PMID: 31990947 PMCID: PMC6986700 DOI: 10.1371/journal.pone.0223034] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Accepted: 12/17/2019] [Indexed: 11/18/2022] Open
Abstract
The ability to modify behavior based on prior experience is essential to an animal's survival. For example, animals may become attracted to a previously neutral odor or reject a previously appetitive food source based on previous encounters. In Drosophila, the mushroom bodies (MBs) are critical for olfactory associative learning and conditioned taste aversion, but how the output of the MBs affects specific behavioral responses is unresolved. In conditioned taste aversion, Drosophila shows a specific behavioral change upon learning: proboscis extension to sugar is reduced after a sugar stimulus is paired with an aversive stimulus. While studies have identified MB output neurons (MBONs) that drive approach or avoidance behavior, whether the same MBONs impact innate proboscis extension behavior is unknown. Here, we tested the role of MB pathways in altering proboscis extension and identified MBONs that synapse onto multiple MB compartments that upon activation significantly decreased proboscis extension to sugar. Activating several of these lines also decreased sugar consumption, revealing that these MBONs have a general role in modifying feeding behavior beyond proboscis extension. The MBONs that decreased proboscis extension and ingestion are different from those that drive avoidance behavior in another context. These studies provide insight into how activation of MB output neurons decreases proboscis extension to taste compounds.
Collapse
Affiliation(s)
- Justine Chia
- Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, University of California, Berkeley, California, United States of America
| | - Kristin Scott
- Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, University of California, Berkeley, California, United States of America
- * E-mail:
| |
Collapse
|
28
|
Currier TA, Nagel KI. Multisensory control of navigation in the fruit fly. Curr Opin Neurobiol 2019; 64:10-16. [PMID: 31841944 DOI: 10.1016/j.conb.2019.11.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 11/23/2019] [Accepted: 11/25/2019] [Indexed: 01/16/2023]
Abstract
Spatial navigation is influenced by cues from nearly every sensory modality and thus provides an excellent model for understanding how different sensory streams are integrated to drive behavior. Here we review recent work on multisensory control of navigation in the model organism Drosophila melanogaster, which allows for detailed circuit dissection. We identify four modes of integration that have been described in the literature-suppression, gating, summation, and association-and describe regions of the larval and adult brain that have been implicated in sensory integration. Finally we discuss what circuit architectures might support these different forms of integration. We argue that Drosophila is an excellent model to discover these circuit and biophysical motifs.
Collapse
Affiliation(s)
- Timothy A Currier
- Neuroscience Institute, New York University Medical Center, 435 E 30th St., New York, NY 10016, USA; Center for Neural Science, New York University, 4 Washington Place, New York, NY 10003, USA
| | - Katherine I Nagel
- Neuroscience Institute, New York University Medical Center, 435 E 30th St., New York, NY 10016, USA; Center for Neural Science, New York University, 4 Washington Place, New York, NY 10003, USA.
| |
Collapse
|
29
|
Sugar Promotes Feeding in Flies via the Serine Protease Homolog scarface. Cell Rep 2019; 24:3194-3206.e4. [PMID: 30232002 PMCID: PMC6167639 DOI: 10.1016/j.celrep.2018.08.059] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 05/08/2018] [Accepted: 08/21/2018] [Indexed: 11/24/2022] Open
Abstract
A balanced diet of macronutrients is critical for animal health. A lack of specific elements can have profound effects on behavior, reproduction, and lifespan. Here, we used Drosophila to understand how the brain responds to carbohydrate deprivation. We found that serine protease homologs (SPHs) are enriched among genes that are transcriptionally regulated in flies deprived of carbohydrates. Stimulation of neurons expressing one of these SPHs, Scarface (Scaf), or overexpression of scaf positively regulates feeding on nutritious sugars, whereas inhibition of these neurons or knockdown of scaf reduces feeding. This modulation of food intake occurs only in sated flies while hunger-induced feeding is unaffected. Furthermore, scaf expression correlates with the presence of sugar in the food. As Scaf and Scaf neurons promote feeding independent of the hunger state, and the levels of scaf are positively regulated by the presence of sugar, we conclude that scaf mediates the hedonic control of feeding. The fly brain responds to specific macronutrients via distinct signaling pathways Serine protease homologs act as neuromodulators under sugar deprivation Sugar is both necessary and sufficient to maintain expression levels of scarface Scarface and Scarface neurons mediate hedonic control of feeding in flies
Collapse
|
30
|
Zhao B, Sun J, Zhang X, Mo H, Niu Y, Li Q, Wang L, Zhong Y. Long-term memory is formed immediately without the need for protein synthesis-dependent consolidation in Drosophila. Nat Commun 2019; 10:4550. [PMID: 31591396 PMCID: PMC6779902 DOI: 10.1038/s41467-019-12436-7] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2019] [Accepted: 09/04/2019] [Indexed: 12/21/2022] Open
Abstract
It is believed that long-term memory (LTM) cannot be formed immediately because it must go through a protein synthesis-dependent consolidation process. However, the current study uses Drosophila aversive olfactory conditioning to show that such processes are dispensable for context-dependent LTM (cLTM). Single-trial conditioning yields cLTM that is formed immediately in a protein-synthesis independent manner and is sustained over 14 days without decay. Unlike retrieval of traditional LTM, which requires only the conditioned odour and is mediated by mushroom-body neurons, cLTM recall requires both the conditioned odour and reinstatement of the training-environmental context. It is mediated through lateral-horn neurons that connect to multiple sensory brain regions. The cLTM cannot be retrieved if synaptic transmission from any one of these centres is blocked, with effects similar to those of altered encoding context during retrieval. The present study provides strong evidence that long-term memory can be formed easily without the need for consolidation. New protein synthesis is known to be indispensable for the consolidation of long-term memory. Here, the authors report that an olfactory memory can be successfully recalled after 14 days without protein synthesis when the training context is also provided in addition to the conditioned odor.
Collapse
Affiliation(s)
- Bohan Zhao
- Tsinghua-Peking Center for Life Sciences, IDG/McGovern Institute for Brain Research and School of Life Sciences, Tsinghua University, 100084, Beijing, China
| | - Jiameng Sun
- Tsinghua-Peking Center for Life Sciences, IDG/McGovern Institute for Brain Research and School of Life Sciences, Tsinghua University, 100084, Beijing, China
| | - Xuchen Zhang
- Tsinghua-Peking Center for Life Sciences, IDG/McGovern Institute for Brain Research and School of Life Sciences, Tsinghua University, 100084, Beijing, China
| | - Han Mo
- Tsinghua-Peking Center for Life Sciences, IDG/McGovern Institute for Brain Research and School of Life Sciences, Tsinghua University, 100084, Beijing, China
| | - Yijun Niu
- Tsinghua-Peking Center for Life Sciences, IDG/McGovern Institute for Brain Research and School of Life Sciences, Tsinghua University, 100084, Beijing, China
| | - Qian Li
- Tsinghua-Peking Center for Life Sciences, IDG/McGovern Institute for Brain Research and School of Life Sciences, Tsinghua University, 100084, Beijing, China
| | - Lianzhang Wang
- Tsinghua-Peking Center for Life Sciences, IDG/McGovern Institute for Brain Research and School of Life Sciences, Tsinghua University, 100084, Beijing, China
| | - Yi Zhong
- Tsinghua-Peking Center for Life Sciences, IDG/McGovern Institute for Brain Research and School of Life Sciences, Tsinghua University, 100084, Beijing, China.
| |
Collapse
|
31
|
Chen YCD, Ahmad S, Amin K, Dahanukar A. A subset of brain neurons controls regurgitation in adult Drosophila melanogaster. J Exp Biol 2019; 222:jeb210724. [PMID: 31511344 PMCID: PMC6806010 DOI: 10.1242/jeb.210724] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 09/03/2019] [Indexed: 12/26/2022]
Abstract
Taste is essential for animals to evaluate food quality and make important decisions about food choice and intake. How complex brains process sensory information to produce behavior is an essential question in the field of sensory neurobiology. Currently, little is known about higher-order taste circuits in the brain as compared with those of other sensory systems. Here, we used the common vinegar fly, Drosophila melanogaster, to screen for candidate neurons labeled by different transgenic GAL4 lines in controlling feeding behaviors. We found that activation of one line (VT041723-GAL4) produces 'proboscis holding' behavior (extrusion of the mouthpart without withdrawal). Further analysis showed that the proboscis holding phenotype indicates an aversive response, as flies pre-fed with either sucrose or water prior to neuronal activation exhibited regurgitation. Anatomical characterization of VT041723-GAL4-labeled neurons suggests that they receive sensory input from peripheral taste neurons. Overall, our study identifies a subset of brain neurons labeled by VT041723-GAL4 that may be involved in a taste circuit that controls regurgitation.
Collapse
Affiliation(s)
- Yu-Chieh David Chen
- Interdepartmental Neuroscience Program, University of California, Riverside, CA 92521, USA
| | - Sameera Ahmad
- Department of Biology, University of California, Riverside, CA 92521, USA
| | - Kush Amin
- Department of Biology, University of California, Riverside, CA 92521, USA
| | - Anupama Dahanukar
- Interdepartmental Neuroscience Program, University of California, Riverside, CA 92521, USA
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, CA 92521, USA
| |
Collapse
|
32
|
Sayin S, De Backer JF, Siju KP, Wosniack ME, Lewis LP, Frisch LM, Gansen B, Schlegel P, Edmondson-Stait A, Sharifi N, Fisher CB, Calle-Schuler SA, Lauritzen JS, Bock DD, Costa M, Jefferis GSXE, Gjorgjieva J, Grunwald Kadow IC. A Neural Circuit Arbitrates between Persistence and Withdrawal in Hungry Drosophila. Neuron 2019; 104:544-558.e6. [PMID: 31471123 PMCID: PMC6839618 DOI: 10.1016/j.neuron.2019.07.028] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 06/09/2019] [Accepted: 07/22/2019] [Indexed: 01/24/2023]
Abstract
In pursuit of food, hungry animals mobilize significant energy resources and overcome exhaustion and fear. How need and motivation control the decision to continue or change behavior is not understood. Using a single fly treadmill, we show that hungry flies persistently track a food odor and increase their effort over repeated trials in the absence of reward suggesting that need dominates negative experience. We further show that odor tracking is regulated by two mushroom body output neurons (MBONs) connecting the MB to the lateral horn. These MBONs, together with dopaminergic neurons and Dop1R2 signaling, control behavioral persistence. Conversely, an octopaminergic neuron, VPM4, which directly innervates one of the MBONs, acts as a brake on odor tracking by connecting feeding and olfaction. Together, our data suggest a function for the MB in internal state-dependent expression of behavior that can be suppressed by external inputs conveying a competing behavioral drive. Hunger motivates persistent food odor tracking even without reward Two synaptically connected MBONs, -γ1pedc>αβ and -α2sc, regulate odor tracking Octopamine neurons connect feeding and counteract MBON and odor tracking Dopaminergic neurons and Dop1R2 signaling promote persistent tracking
Collapse
Affiliation(s)
- Sercan Sayin
- Technical University of Munich, School of Life Sciences, 85354 Freising, Germany
| | | | - K P Siju
- Technical University of Munich, School of Life Sciences, 85354 Freising, Germany
| | - Marina E Wosniack
- Technical University of Munich, School of Life Sciences, 85354 Freising, Germany; Max Planck Institute for Brain Research, Computation in Neural Circuits Group, 60438 Frankfurt, Germany
| | - Laurence P Lewis
- Max Planck Institute of Neurobiology, Chemosensory Coding Group, 82152 Martinsried, Germany
| | - Lisa-Marie Frisch
- Technical University of Munich, School of Life Sciences, 85354 Freising, Germany
| | - Benedikt Gansen
- Technical University of Munich, School of Life Sciences, 85354 Freising, Germany
| | - Philipp Schlegel
- Drosophila Connectomics Group, Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, UK
| | - Amelia Edmondson-Stait
- Drosophila Connectomics Group, Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, UK
| | | | | | | | | | - Davi D Bock
- HHMI Janelia Research Campus, Ashburn, VA 20147, USA
| | - Marta Costa
- Drosophila Connectomics Group, Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, UK
| | - Gregory S X E Jefferis
- Drosophila Connectomics Group, Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, UK; Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Julijana Gjorgjieva
- Technical University of Munich, School of Life Sciences, 85354 Freising, Germany; Max Planck Institute for Brain Research, Computation in Neural Circuits Group, 60438 Frankfurt, Germany
| | - Ilona C Grunwald Kadow
- Technical University of Munich, School of Life Sciences, 85354 Freising, Germany; ZIEL - Institute for food and health, 85354 Freising, Germany; Max Planck Institute of Neurobiology, Chemosensory Coding Group, 82152 Martinsried, Germany.
| |
Collapse
|
33
|
Musso PY, Junca P, Jelen M, Feldman-Kiss D, Zhang H, Chan RC, Gordon MD. Closed-loop optogenetic activation of peripheral or central neurons modulates feeding in freely moving Drosophila. eLife 2019; 8:45636. [PMID: 31322499 PMCID: PMC6668987 DOI: 10.7554/elife.45636] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 07/18/2019] [Indexed: 12/25/2022] Open
Abstract
Manipulating feeding circuits in freely moving animals is challenging, in part because the timing of sensory inputs is affected by the animal's behavior. To address this challenge in Drosophila, we developed the Sip-Triggered Optogenetic Behavior Enclosure ('STROBE'). The STROBE is a closed-looped system for real-time optogenetic activation of feeding flies, designed to evoke neural excitation coincident with food contact. We previously demonstrated the STROBE's utility in probing the valence of fly sensory neurons (Jaeger et al., 2018). Here we provide a thorough characterization of the STROBE system, demonstrate that STROBE-driven behavior is modified by hunger and the presence of taste ligands, and find that mushroom body dopaminergic input neurons and their respective post-synaptic partners drive opposing feeding behaviors following activation. Together, these results establish the STROBE as a new tool for dissecting fly feeding circuits and suggest a role for mushroom body circuits in processing naïve taste responses.
Collapse
Affiliation(s)
- Pierre-Yves Musso
- Department of Zoology, Life Sciences Institute, University of British Columbia, Vancouver, Canada
| | - Pierre Junca
- Department of Zoology, Life Sciences Institute, University of British Columbia, Vancouver, Canada
| | - Meghan Jelen
- Department of Zoology, Life Sciences Institute, University of British Columbia, Vancouver, Canada
| | - Damian Feldman-Kiss
- Department of Zoology, Life Sciences Institute, University of British Columbia, Vancouver, Canada
| | - Han Zhang
- Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada
| | - Rachel Cw Chan
- Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada
| | - Michael D Gordon
- Department of Zoology, Life Sciences Institute, University of British Columbia, Vancouver, Canada
| |
Collapse
|
34
|
Reisenman CE, Scott K. Food-derived volatiles enhance consumption in Drosophila melanogaster. ACTA ACUST UNITED AC 2019; 222:jeb.202762. [PMID: 31085598 DOI: 10.1242/jeb.202762] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Accepted: 05/02/2019] [Indexed: 11/20/2022]
Abstract
Insects use multiple sensory modalities when searching for and accepting a food source, in particular odor and taste cues. Food-derived odorants are generally involved in mediating long- and short-range attraction. Taste cues, in contrast, act directly by contact with the food source, promoting the ingestion of nutritious food and the avoidance of toxic substances. It is possible, however, that insects integrate information from these sensory modalities during the process of feeding itself. Here, using a simple feeding assay, we investigated whether odors modulate food consumption in the fruit fly Drosophila melanogaster We found that the presence of both single food-derived odorants and complex odor mixtures enhanced consumption of an appetitive food. Feeding enhancement depended on the concentration and the chemical identity of the odorant. Volatile cues alone were sufficient to mediate this effect, as feeding was also increased when animals were prevented from contacting the odor source. Both males and females, including virgin females, increased ingestion in the presence of food-derived volatiles. Moreover, the presence of food-derived odorants significantly increased the consumption of food mixtures containing aversive bitter compounds, suggesting that flies integrate diverse olfactory and gustatory cues to guide feeding decisions, including situations in which animals are confronted with stimuli of opposite valence. Overall, these results show that food-derived olfactory cues directly modulate feeding in D. melanogaster, enhancing ingestion.
Collapse
Affiliation(s)
- Carolina E Reisenman
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA 94720, USA .,Essig Museum of Entomology, University of California Berkeley, Berkeley, CA 94720, USA
| | - Kristin Scott
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA 94720, USA.,Helen Wills Neuroscience Institute, University of California Berkeley, Berkeley, CA 94720, USA
| |
Collapse
|
35
|
Dolan MJ, Frechter S, Bates AS, Dan C, Huoviala P, Roberts RJV, Schlegel P, Dhawan S, Tabano R, Dionne H, Christoforou C, Close K, Sutcliffe B, Giuliani B, Li F, Costa M, Ihrke G, Meissner GW, Bock DD, Aso Y, Rubin GM, Jefferis GSXE. Neurogenetic dissection of the Drosophila lateral horn reveals major outputs, diverse behavioural functions, and interactions with the mushroom body. eLife 2019; 8:e43079. [PMID: 31112130 PMCID: PMC6529221 DOI: 10.7554/elife.43079] [Citation(s) in RCA: 84] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 02/07/2019] [Indexed: 01/26/2023] Open
Abstract
Animals exhibit innate behaviours to a variety of sensory stimuli including olfactory cues. In Drosophila, one higher olfactory centre, the lateral horn (LH), is implicated in innate behaviour. However, our structural and functional understanding of the LH is scant, in large part due to a lack of sparse neurogenetic tools for this region. We generate a collection of split-GAL4 driver lines providing genetic access to 82 LH cell types. We use these to create an anatomical and neurotransmitter map of the LH and link this to EM connectomics data. We find ~30% of LH projections converge with outputs from the mushroom body, site of olfactory learning and memory. Using optogenetic activation, we identify LH cell types that drive changes in valence behavior or specific locomotor programs. In summary, we have generated a resource for manipulating and mapping LH neurons, providing new insights into the circuit basis of innate and learned olfactory behavior.
Collapse
Affiliation(s)
- Michael-John Dolan
- Howard Hughes Medical Institute, Janelia Research CampusAshburnUnited States
- Division of NeurobiologyMRC Laboratory of Molecular BiologyCambridgeUnited Kingdom
| | - Shahar Frechter
- Division of NeurobiologyMRC Laboratory of Molecular BiologyCambridgeUnited Kingdom
| | | | - Chuntao Dan
- Howard Hughes Medical Institute, Janelia Research CampusAshburnUnited States
| | - Paavo Huoviala
- Division of NeurobiologyMRC Laboratory of Molecular BiologyCambridgeUnited Kingdom
| | | | - Philipp Schlegel
- Division of NeurobiologyMRC Laboratory of Molecular BiologyCambridgeUnited Kingdom
- Department of ZoologyUniversity of CambridgeCambridgeUnited Kingdom
| | - Serene Dhawan
- Division of NeurobiologyMRC Laboratory of Molecular BiologyCambridgeUnited Kingdom
- Department of ZoologyUniversity of CambridgeCambridgeUnited Kingdom
| | - Remy Tabano
- Howard Hughes Medical Institute, Janelia Research CampusAshburnUnited States
| | - Heather Dionne
- Howard Hughes Medical Institute, Janelia Research CampusAshburnUnited States
| | | | - Kari Close
- Howard Hughes Medical Institute, Janelia Research CampusAshburnUnited States
| | - Ben Sutcliffe
- Division of NeurobiologyMRC Laboratory of Molecular BiologyCambridgeUnited Kingdom
| | - Bianca Giuliani
- Howard Hughes Medical Institute, Janelia Research CampusAshburnUnited States
| | - Feng Li
- Howard Hughes Medical Institute, Janelia Research CampusAshburnUnited States
| | - Marta Costa
- Department of ZoologyUniversity of CambridgeCambridgeUnited Kingdom
| | - Gudrun Ihrke
- Howard Hughes Medical Institute, Janelia Research CampusAshburnUnited States
| | | | - Davi D Bock
- Howard Hughes Medical Institute, Janelia Research CampusAshburnUnited States
| | - Yoshinori Aso
- Howard Hughes Medical Institute, Janelia Research CampusAshburnUnited States
| | - Gerald M Rubin
- Howard Hughes Medical Institute, Janelia Research CampusAshburnUnited States
| | - Gregory SXE Jefferis
- Howard Hughes Medical Institute, Janelia Research CampusAshburnUnited States
- Division of NeurobiologyMRC Laboratory of Molecular BiologyCambridgeUnited Kingdom
- Department of ZoologyUniversity of CambridgeCambridgeUnited Kingdom
| |
Collapse
|
36
|
Frechter S, Bates AS, Tootoonian S, Dolan MJ, Manton J, Jamasb AR, Kohl J, Bock D, Jefferis G. Functional and anatomical specificity in a higher olfactory centre. eLife 2019; 8:44590. [PMID: 31112127 PMCID: PMC6550879 DOI: 10.7554/elife.44590] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 04/12/2019] [Indexed: 12/16/2022] Open
Abstract
Most sensory systems are organized into parallel neuronal pathways that process distinct aspects of incoming stimuli. In the insect olfactory system, second order projection neurons target both the mushroom body, required for learning, and the lateral horn (LH), proposed to mediate innate olfactory behavior. Mushroom body neurons form a sparse olfactory population code, which is not stereotyped across animals. In contrast, odor coding in the LH remains poorly understood. We combine genetic driver lines, anatomical and functional criteria to show that the Drosophila LH has ~1400 neurons and >165 cell types. Genetically labeled LHNs have stereotyped odor responses across animals and on average respond to three times more odors than single projection neurons. LHNs are better odor categorizers than projection neurons, likely due to stereotyped pooling of related inputs. Our results reveal some of the principles by which a higher processing area can extract innate behavioral significance from sensory stimuli.
Collapse
Affiliation(s)
- Shahar Frechter
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | | | - Sina Tootoonian
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom.,Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom.,Neurophysiology of Behaviour Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Michael-John Dolan
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom.,Janelia Research Campus, Howard Hughes Medical Institute, Chevy Chase, United States
| | - James Manton
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | | | - Johannes Kohl
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Davi Bock
- Janelia Research Campus, Howard Hughes Medical Institute, Chevy Chase, United States
| | - Gregory Jefferis
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom.,Department of Zoology, University of Cambridge, Cambridge, United Kingdom
| |
Collapse
|
37
|
He Z, Luo Y, Shang X, Sun JS, Carlson JR. Chemosensory sensilla of the Drosophila wing express a candidate ionotropic pheromone receptor. PLoS Biol 2019; 17:e2006619. [PMID: 31112532 PMCID: PMC6528970 DOI: 10.1371/journal.pbio.2006619] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 04/05/2019] [Indexed: 12/01/2022] Open
Abstract
The Drosophila wing was proposed to be a taste organ more than 35 years ago, but there has been remarkably little study of its role in chemoreception. We carry out a differential RNA-seq analysis of a row of sensilla on the anterior wing margin and find expression of many genes associated with pheromone and chemical perception. To ask whether these sensilla might receive pheromonal input, we devised a dye-transfer paradigm and found that large, hydrophobic molecules comparable to pheromones can be transferred from one fly to the wing margin of another. One gene, Ionotropic receptor (IR)52a, is coexpressed in neurons of these sensilla with fruitless, a marker of sexual circuitry; IR52a is also expressed in legs. Mutation of IR52a and optogenetic silencing of IR52a+ neurons decrease levels of male sexual behavior. Optogenetic activation of IR52a+ neurons induces males to show courtship toward other males and, remarkably, toward females of another species. Surprisingly, IR52a is also required in females for normal sexual behavior. Optogenetic activation of IR52a+ neurons in mated females induces copulation, which normally occurs at very low levels. Unlike other chemoreceptors that act in males to inhibit male–male interactions and promote male–female interactions, IR52a acts in both males and females, and can promote male–male as well as male–female interactions. Moreover, IR52a+ neurons can override the circuitry that normally suppresses sexual behavior toward unproductive targets. Circuit mapping and Ca2+ imaging using the trans-Tango system reveals second-order projections of IR52a+ neurons in the subesophageal zone (SEZ), some of which are sexually dimorphic. Optogenetic activation of IR52a+ neurons in the wing activates second-order projections in the SEZ. Taken together, this study provides a molecular description of the chemosensory sensilla of a greatly understudied taste organ and defines a gene that regulates the sexual circuitry of the fly.
Collapse
Affiliation(s)
- Zhe He
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut, United States of America
| | - Yichen Luo
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut, United States of America
| | - Xueying Shang
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut, United States of America
| | - Jennifer S. Sun
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut, United States of America
| | - John R. Carlson
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut, United States of America
- * E-mail:
| |
Collapse
|
38
|
Kaushik S, Kumar R, Kain P. Salt an Essential Nutrient: Advances in Understanding Salt Taste Detection Using Drosophila as a Model System. J Exp Neurosci 2018; 12:1179069518806894. [PMID: 30479487 PMCID: PMC6249657 DOI: 10.1177/1179069518806894] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Accepted: 09/19/2018] [Indexed: 11/16/2022] Open
Abstract
Taste modalities are conserved in insects and mammals. Sweet gustatory signals evoke attractive behaviors while bitter gustatory information drive aversive behaviors. Salt (NaCl) is an essential nutrient required for various physiological processes, including electrolyte homeostasis, neuronal activity, nutrient absorption, and muscle contraction. Not only mammals, even in Drosophila melanogaster, the detection of NaCl induces two different behaviors: Low concentrations of NaCl act as an attractant, whereas high concentrations act as repellant. The fruit fly is an excellent model system for studying the underlying mechanisms of salt taste due to its relatively simple neuroanatomical organization of the brain and peripheral taste system, the availability of powerful genetic tools and transgenic strains. In this review, we have revisited the literature and the information provided by various laboratories using invertebrate model system Drosophila that has helped us to understand NaCl salt taste so far. We hope that this compiled information from Drosophila will be of general significance and interest for forthcoming studies of the structure, function, and behavioral role of NaCl-sensitive (low and high concentrations) gustatory circuitry for understanding NaCl salt taste in all animals.
Collapse
Affiliation(s)
- Shivam Kaushik
- Department of Neurobiology and Genetics, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, India
| | - Rahul Kumar
- Department of Neurobiology and Genetics, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, India.,Department of Biotechnology, Maharshi Dayanand University, Rohtak, India
| | - Pinky Kain
- Department of Neurobiology and Genetics, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, India
| |
Collapse
|
39
|
Tsubouchi A, Yano T, Yokoyama TK, Murtin C, Otsuna H, Ito K. Topological and modality-specific representation of somatosensory information in the fly brain. Science 2018; 358:615-623. [PMID: 29097543 DOI: 10.1126/science.aan4428] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 09/25/2017] [Indexed: 12/11/2022]
Abstract
Insects and mammals share similarities of neural organization underlying the perception of odors, taste, vision, sound, and gravity. We observed that insect somatosensation also corresponds to that of mammals. In Drosophila, the projections of all the somatosensory neuron types to the insect's equivalent of the spinal cord segregated into modality-specific layers comparable to those in mammals. Some sensory neurons innervate the ventral brain directly to form modality-specific and topological somatosensory maps. Ascending interneurons with dendrites in matching layers of the nerve cord send axons that converge to respective brain regions. Pathways arising from leg somatosensory neurons encode distinct qualities of leg movement information and play different roles in ground detection. Establishment of the ground pattern and genetic tools for neuronal manipulation should provide the basis for elucidating the mechanisms underlying somatosensation.
Collapse
Affiliation(s)
- Asako Tsubouchi
- Institute of Molecular and Cellular Biosciences, The University of Tokyo, Yayoi, Bunkyo-ku, 113-0032 Tokyo, Japan
| | - Tomoko Yano
- Institute of Molecular and Cellular Biosciences, The University of Tokyo, Yayoi, Bunkyo-ku, 113-0032 Tokyo, Japan.,Department of Computational Biology, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwanoha, Kashiwa, 277-0882 Chiba, Japan
| | - Takeshi K Yokoyama
- Institute of Molecular and Cellular Biosciences, The University of Tokyo, Yayoi, Bunkyo-ku, 113-0032 Tokyo, Japan
| | - Chloé Murtin
- Institute of Molecular and Cellular Biosciences, The University of Tokyo, Yayoi, Bunkyo-ku, 113-0032 Tokyo, Japan.,Department of Computational Biology, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwanoha, Kashiwa, 277-0882 Chiba, Japan
| | - Hideo Otsuna
- Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, VA 20147, USA
| | - Kei Ito
- Institute of Molecular and Cellular Biosciences, The University of Tokyo, Yayoi, Bunkyo-ku, 113-0032 Tokyo, Japan. .,Department of Computational Biology, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwanoha, Kashiwa, 277-0882 Chiba, Japan.,Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, VA 20147, USA.,Institute of Zoology, University of Cologne, 50674 Cologne, Germany
| |
Collapse
|
40
|
Identification of a Single Pair of Interneurons for Bitter Taste Processing in the Drosophila Brain. Curr Biol 2018; 28:847-858.e3. [PMID: 29502953 DOI: 10.1016/j.cub.2018.01.084] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 10/20/2017] [Accepted: 01/30/2018] [Indexed: 11/23/2022]
Abstract
Drosophila has become an excellent model system for investigating the organization and function of the gustatory system due to the relatively simple neuroanatomical organization of its brain and the availability of powerful genetic and transgenic technology. Thus, at the molecular and cellular levels, a great deal of insight into the peripheral detection and coding of gustatory information has already been attained. In contrast, much less is known about the central neural circuits that process this information and induce behaviorally appropriate motor output. Here, we combine functional behavioral tests with targeted transgene expression through specific driver lines to identify a single bilaterally homologous pair of bitter-sensitive interneurons that are located in the subesophageal zone of the brain. Anatomical and functional data indicate that these interneurons receive specific synaptic input from bitter-sensitive gustatory receptor neurons. Targeted transgenic activation and inactivation experiments show that these bitter-sensitive interneurons can largely suppress the proboscis extension reflex to appetitive stimuli, such as sugar and water. These functional experiments, together with calcium-imaging studies and calcium-modulated photoactivatable ratiometric integrator (CaMPARI) labeling, indicate that these first-order local interneurons play an important role in the inhibition of the proboscis extension reflex that occurs in response to bitter tastants. Taken together, our studies present a cellular identification and functional characterization of a key gustatory interneuron in the bitter-sensitive gustatory circuitry of the adult fly.
Collapse
|
41
|
Abstract
The ability to identify nutrient-rich food and avoid toxic substances is essential for an animal's survival. Although olfaction and vision contribute to food detection, the gustatory system acts as a final checkpoint control for food acceptance or rejection. The vinegar fly Drosophila melanogaster tastes many of the same stimuli as mammals and provides an excellent model system for comparative studies of taste detection. The relative simplicity of the fly brain and behaviors, along with the molecular genetic and functional approaches available in this system, allow the examination of gustatory neural circuits from sensory input to motor output. This review discusses the molecules and cells that detect taste compounds in the periphery and the circuits that process taste information in the brain. These studies are providing insight into how the detection of taste compounds regulates feeding decisions.
Collapse
Affiliation(s)
- Kristin Scott
- Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, University of California, Berkeley, California 94720;
| |
Collapse
|
42
|
Cording AC, Shiaelis N, Petridi S, Middleton CA, Wilson LG, Elliott CJH. Targeted kinase inhibition relieves slowness and tremor in a Drosophila model of LRRK2 Parkinson's disease. NPJ PARKINSONS DISEASE 2017; 3:34. [PMID: 29214211 PMCID: PMC5715132 DOI: 10.1038/s41531-017-0036-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 11/03/2017] [Accepted: 11/07/2017] [Indexed: 11/25/2022]
Abstract
In a number of Drosophila models of genetic Parkinson’s disease (PD) flies climb more slowly than wild-type controls. However, this assay does not distinguish effects of PD-related genes on gravity sensation, “arousal”, central pattern generation of leg movements, or muscle. To address this problem, we have developed an assay for the fly proboscis extension response (PER). This is attractive because the PER has a simple, well-identified reflex neural circuit, in which sucrose sensing neurons activate a pair of “command interneurons”, and thence motoneurons whose activity contracts the proboscis muscle. This circuit is modulated by a single dopaminergic neuron (TH-VUM). We find that expressing either the G2019S or I2020T (but not R1441C, or kinase dead) forms of human LRRK2 in dopaminergic neurons reduces the percentage of flies that initially respond to sucrose stimulation. This is rescued fully by feeding l-DOPA and partially by feeding kinase inhibitors, targeted to LRRK2 (LRRK2-IN-1 and BMPPB-32). High-speed video shows that G2019S expression in dopaminergic neurons slows the speed of proboscis extension, makes its duration more variable, and increases the tremor. Testing subsets of dopaminergic neurons suggests that the single TH-VUM neuron is likely most important in this phenotype. We conclude the Drosophila PER provides an excellent model of LRRK2 motor deficits showing bradykinesia, akinesia, hypokinesia, and increased tremor, with the possibility to localize changes in neural signaling. A simple reflex in flies can be used to test the effectiveness of therapies that slow neurodegeneration in Parkinson’s disease (PD). Christopher Elliott and colleagues at the University of York in the United Kingdom investigated the contraction of the proboscis muscle which mediates a taste behavior response and is regulated by a single dopaminergic neuron. Flies bearing particular mutations in the PD-associated gene leucine-rich repeat kinase 2 (LRRK2) in dopaminergic neurons lost their ability to feed on a sweet solution. This was due to the movement of the proboscis muscle becoming slower and stiffer, hallmark features of PD. The authors rescued the impaired reflex reaction by feeding the flies l-DOPA or LRRK2 inhibitors. These findings highlight the proboscis extension response as a useful tool to identify other PD-associated mutations and test potential therapeutic compounds.
Collapse
Affiliation(s)
- Amy C Cording
- Department of Biology, University of York, York, YO1 5DD UK
| | | | | | | | | | | |
Collapse
|
43
|
The Role of the Gustatory System in the Coordination of Feeding. eNeuro 2017; 4:eN-REV-0324-17. [PMID: 29159281 PMCID: PMC5694965 DOI: 10.1523/eneuro.0324-17.2017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 10/19/2017] [Accepted: 10/25/2017] [Indexed: 11/21/2022] Open
Abstract
To survive, all animals must find, inspect, and ingest food. Behavioral coordination and control of feeding is therefore a challenge that animals must face. Here, we focus on how the gustatory system guides the precise execution of behavioral sequences that promote ingestion and suppresses competing behaviors. We summarize principles learnt from Drosophila, where underlying sensory neuronal mechanisms are illustrated in great detail. Moreover, we compare these principles with findings in other animals, where such coordination plays prominent roles. These examples suggest that the use of gustatory information for feeding coordination has an ancient origin and is prevalent throughout the animal kingdom.
Collapse
|
44
|
Transsynaptic Mapping of Second-Order Taste Neurons in Flies by trans-Tango. Neuron 2017; 96:783-795.e4. [PMID: 29107518 DOI: 10.1016/j.neuron.2017.10.011] [Citation(s) in RCA: 169] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Revised: 06/30/2017] [Accepted: 10/05/2017] [Indexed: 12/27/2022]
Abstract
Mapping neural circuits across defined synapses is essential for understanding brain function. Here we describe trans-Tango, a technique for anterograde transsynaptic circuit tracing and manipulation. At the core of trans-Tango is a synthetic signaling pathway that is introduced into all neurons in the animal. This pathway converts receptor activation at the cell surface into reporter expression through site-specific proteolysis. Specific labeling is achieved by presenting a tethered ligand at the synapses of genetically defined neurons, thereby activating the pathway in their postsynaptic partners and providing genetic access to these neurons. We first validated trans-Tango in the Drosophila olfactory system and then implemented it in the gustatory system, where projections beyond the first-order receptor neurons are not fully characterized. We identified putative second-order neurons within the sweet circuit that include projection neurons targeting known neuromodulation centers in the brain. These experiments establish trans-Tango as a flexible platform for transsynaptic circuit analysis.
Collapse
|