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Comyn T, Preat T, Pavlowsky A, Plaçais PY. PKCδ is an activator of neuronal mitochondrial metabolism that mediates the spacing effect on memory consolidation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.10.06.561186. [PMID: 38948698 PMCID: PMC11212906 DOI: 10.1101/2023.10.06.561186] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
Relevance-based selectivity and high energy cost are two distinct features of long-term memory (LTM) formation that warrant its default inhibition. Spaced repetition of learning is a highly conserved cognitive mechanism that can lift this inhibition. Here, we questioned how the spacing effect integrates experience selection and energy efficiency at the cellular and molecular levels. We showed in Drosophila that spaced training triggers LTM formation by extending over several hours an increased mitochondrial metabolic activity in neurons of the associative memory center, the mushroom bodies (MBs). We found that this effect is mediated by PKCδ, a member of the so-called 'novel PKC' family of enzymes, which uncovers the critical function of PKCδ in neurons as a regulator of mitochondrial metabolism for LTM. Additionally, PKCδ activation and translocation to mitochondria result from LTM-specific dopamine signaling on MB neurons. By bridging experience-dependent neuronal circuit activity with metabolic modulation of memory-encoding neurons, PKCδ signaling binds the cognitive and metabolic constraints underlying LTM formation into a unified gating mechanism.
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2
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Pavlowsky A, Comyn T, Minatchy J, Geny D, Bun P, Danglot L, Preat T, Plaçais PY. Spaced training activates Miro/Milton-dependent mitochondrial dynamics in neuronal axons to sustain long-term memory. Curr Biol 2024; 34:1904-1917.e6. [PMID: 38642548 DOI: 10.1016/j.cub.2024.03.050] [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: 01/23/2023] [Revised: 12/21/2023] [Accepted: 03/25/2024] [Indexed: 04/22/2024]
Abstract
Neurons have differential and fluctuating energy needs across distinct cellular compartments, shaped by brain electrochemical activity associated with cognition. In vitro studies show that mitochondria transport from soma to axons is key to maintaining neuronal energy homeostasis. Nevertheless, whether the spatial distribution of neuronal mitochondria is dynamically adjusted in vivo in an experience-dependent manner remains unknown. In Drosophila, associative long-term memory (LTM) formation is initiated by an early and persistent upregulation of mitochondrial pyruvate flux in the axonal compartment of neurons in the mushroom body (MB). Through behavior experiments, super-resolution analysis of mitochondria morphology in the neuronal soma and in vivo mitochondrial fluorescence recovery after photobleaching (FRAP) measurements in the axons, we show that LTM induction, contrary to shorter-lived memories, is sustained by the departure of some mitochondria from MB neuronal soma and increased mitochondrial dynamics in the axonal compartment. Accordingly, impairing mitochondrial dynamics abolished the increased pyruvate consumption, specifically after spaced training and in the MB axonal compartment, thereby preventing LTM formation. Our results thus promote reorganization of the mitochondrial network in neurons as an integral step in elaborating high-order cognitive processes.
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Affiliation(s)
- Alice Pavlowsky
- Energy & Memory, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, 10 rue Vauquelin, 75005 Paris, France
| | - Typhaine Comyn
- Energy & Memory, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, 10 rue Vauquelin, 75005 Paris, France
| | - Julia Minatchy
- Energy & Memory, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, 10 rue Vauquelin, 75005 Paris, France
| | - David Geny
- Université de Paris, NeurImag Imaging Facility, Institute of Psychiatry and Neuroscience of Paris, INSERM U1266, 75014 Paris, France
| | - Philippe Bun
- Université de Paris, NeurImag Imaging Facility, Institute of Psychiatry and Neuroscience of Paris, INSERM U1266, 75014 Paris, France
| | - Lydia Danglot
- Université de Paris, NeurImag Imaging Facility, Institute of Psychiatry and Neuroscience of Paris, INSERM U1266, 75014 Paris, France
| | - Thomas Preat
- Energy & Memory, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, 10 rue Vauquelin, 75005 Paris, France.
| | - Pierre-Yves Plaçais
- Energy & Memory, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, 10 rue Vauquelin, 75005 Paris, France.
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3
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Turrel O, Gao L, Sigrist SJ. Presynaptic regulators in memory formation. Learn Mem 2024; 31:a054013. [PMID: 38862173 PMCID: PMC11199941 DOI: 10.1101/lm.054013.124] [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: 04/04/2024] [Accepted: 04/17/2024] [Indexed: 06/13/2024]
Abstract
The intricate molecular and structural sequences guiding the formation and consolidation of memories within neuronal circuits remain largely elusive. In this study, we investigate the roles of two pivotal presynaptic regulators, the small GTPase Rab3, enriched at synaptic vesicles, and the cell adhesion protein Neurexin-1, in the formation of distinct memory phases within the Drosophila mushroom body Kenyon cells. Our findings suggest that both proteins play crucial roles in memory-supporting processes within the presynaptic terminal, operating within distinct plasticity modules. These modules likely encompass remodeling and maturation of existing active zones (AZs), as well as the formation of new AZs.
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Affiliation(s)
- Oriane Turrel
- Institute for Biology, Genetics, Freie Universität Berlin, 14195 Berlin, Germany
| | - Lili Gao
- Institute for Biology, Genetics, Freie Universität Berlin, 14195 Berlin, Germany
| | - Stephan J Sigrist
- Institute for Biology, Genetics, Freie Universität Berlin, 14195 Berlin, Germany
- Cluster of Excellence NeuroCure, Charité Universitätsmedizin Berlin, 10117 Berlin, Germany
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4
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Pribbenow C, Owald D. Skewing information flow through pre- and postsynaptic plasticity in the mushroom bodies of Drosophila. Learn Mem 2024; 31:a053919. [PMID: 38876487 PMCID: PMC11199954 DOI: 10.1101/lm.053919.124] [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] [Received: 01/10/2024] [Accepted: 04/26/2024] [Indexed: 06/16/2024]
Abstract
Animal brains need to store information to construct a representation of their environment. Knowledge of what happened in the past allows both vertebrates and invertebrates to predict future outcomes by recalling previous experience. Although invertebrate and vertebrate brains share common principles at the molecular, cellular, and circuit-architectural levels, there are also obvious differences as exemplified by the use of acetylcholine versus glutamate as the considered main excitatory neurotransmitters in the respective central nervous systems. Nonetheless, across central nervous systems, synaptic plasticity is thought to be a main substrate for memory storage. Therefore, how brain circuits and synaptic contacts change following learning is of fundamental interest for understanding brain computations tied to behavior in any animal. Recent progress has been made in understanding such plastic changes following olfactory associative learning in the mushroom bodies (MBs) of Drosophila A current framework of memory-guided behavioral selection is based on the MB skew model, in which antagonistic synaptic pathways are selectively changed in strength. Here, we review insights into plasticity at dedicated Drosophila MB output pathways and update what is known about the plasticity of both pre- and postsynaptic compartments of Drosophila MB neurons.
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Affiliation(s)
- Carlotta Pribbenow
- Institute of Neurophysiology, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 10117 Berlin, Germany
| | - David Owald
- Institute of Neurophysiology, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 10117 Berlin, Germany
- Einstein Center for Neurosciences Berlin, 10117 Berlin, Germany
- NeuroCure, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 10117 Berlin, Germany
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5
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Suárez-Grimalt R, Grunwald Kadow IC, Scheunemann L. An integrative sensor of body states: how the mushroom body modulates behavior depending on physiological context. Learn Mem 2024; 31:a053918. [PMID: 38876486 PMCID: PMC11199956 DOI: 10.1101/lm.053918.124] [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] [Received: 01/09/2024] [Accepted: 04/08/2024] [Indexed: 06/16/2024]
Abstract
The brain constantly compares past and present experiences to predict the future, thereby enabling instantaneous and future behavioral adjustments. Integration of external information with the animal's current internal needs and behavioral state represents a key challenge of the nervous system. Recent advancements in dissecting the function of the Drosophila mushroom body (MB) at the single-cell level have uncovered its three-layered logic and parallel systems conveying positive and negative values during associative learning. This review explores a lesser-known role of the MB in detecting and integrating body states such as hunger, thirst, and sleep, ultimately modulating motivation and sensory-driven decisions based on the physiological state of the fly. State-dependent signals predominantly affect the activity of modulatory MB input neurons (dopaminergic, serotoninergic, and octopaminergic), but also induce plastic changes directly at the level of the MB intrinsic and output neurons. Thus, the MB emerges as a tightly regulated relay station in the insect brain, orchestrating neuroadaptations due to current internal and behavioral states leading to short- but also long-lasting changes in behavior. While these adaptations are crucial to ensure fitness and survival, recent findings also underscore how circuit motifs in the MB may reflect fundamental design principles that contribute to maladaptive behaviors such as addiction or depression-like symptoms.
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Affiliation(s)
- Raquel Suárez-Grimalt
- Institute for Biology/Genetics, Freie Universität Berlin, 14195 Berlin, Germany
- Institut für Neurophysiologie and NeuroCure Cluster of Excellence, Charité-Universitätsmedizin Berlin, 10117 Berlin, Germany
| | | | - Lisa Scheunemann
- Institute for Biology/Genetics, Freie Universität Berlin, 14195 Berlin, Germany
- Institut für Neurophysiologie and NeuroCure Cluster of Excellence, Charité-Universitätsmedizin Berlin, 10117 Berlin, Germany
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6
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Basu R, Preat T, Plaçais PY. Glial metabolism versatility regulates mushroom body-driven behavioral output in Drosophila. Learn Mem 2024; 31:a053823. [PMID: 38862167 PMCID: PMC11199944 DOI: 10.1101/lm.053823.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Accepted: 04/23/2024] [Indexed: 06/13/2024]
Abstract
Providing metabolic support to neurons is now recognized as a major function of glial cells that is conserved from invertebrates to vertebrates. However, research in this field has focused for more than two decades on the relevance of lactate and glial glycolysis for neuronal energy metabolism, while overlooking many other facets of glial metabolism and their impact on neuronal physiology, circuit activity, and behavior. Here, we review recent work that has unveiled new features of glial metabolism, especially in Drosophila, in the modulation of behavioral traits involving the mushroom bodies (MBs). These recent findings reveal that spatially and biochemically distinct modes of glucose-derived neuronal fueling are implemented within the MB in a memory type-specific manner. In addition, cortex glia are endowed with several antioxidant functions, whereas astrocytes can serve as pro-oxidant agents that are beneficial to redox signaling underlying long-term memory. Finally, glial fatty acid oxidation seems to play a dual fail-safe role: first, as a mode of energy production upon glucose shortage, and, second, as a factor underlying the clearance of excessive oxidative load during sleep. Altogether, these integrated studies performed in Drosophila indicate that glial metabolism has a deterministic role on behavior.
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Affiliation(s)
- Ruchira Basu
- Energy & Memory, Brain Plasticity (UMR 8249), CNRS, ESPCI Paris, PSL Research University, 75005 Paris, France
| | - Thomas Preat
- Energy & Memory, Brain Plasticity (UMR 8249), CNRS, ESPCI Paris, PSL Research University, 75005 Paris, France
| | - Pierre-Yves Plaçais
- Energy & Memory, Brain Plasticity (UMR 8249), CNRS, ESPCI Paris, PSL Research University, 75005 Paris, France
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7
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Rabah Y, Francés R, Minatchy J, Guédon L, Desnous C, Plaçais PY, Preat T. Glycolysis-derived alanine from glia fuels neuronal mitochondria for memory in Drosophila. Nat Metab 2023; 5:2002-2019. [PMID: 37932430 PMCID: PMC10663161 DOI: 10.1038/s42255-023-00910-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 09/20/2023] [Indexed: 11/08/2023]
Abstract
Glucose is the primary source of energy for the brain; however, it remains controversial whether, upon neuronal activation, glucose is primarily used by neurons for ATP production or if it is partially oxidized in astrocytes, as proposed by the astrocyte-neuron lactate shuttle model for glutamatergic neurons. Thus, an in vivo picture of glucose metabolism during cognitive processes is missing. Here, we uncover in Drosophila melanogaster a glia-to-neuron alanine transfer involving alanine aminotransferase that sustains memory formation. Following associative conditioning, glycolysis in glial cells produces alanine, which is back-converted into pyruvate in cholinergic neurons of the olfactory memory center to uphold their increased mitochondrial needs. Alanine, as a mediator of glia-neuron coupling, could be an alternative to lactate in cholinergic systems. In parallel, a dedicated glial glucose transporter imports glucose specifically for long-term memory, by directly transferring it to neurons for use by the pentose phosphate pathway. Our results demonstrate in vivo the compartmentalization of glucose metabolism between neurons and glial cells during memory formation.
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Affiliation(s)
- Yasmine Rabah
- Energy & Memory, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, Paris, France
| | - Raquel Francés
- Energy & Memory, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, Paris, France
| | - Julia Minatchy
- Energy & Memory, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, Paris, France
| | - Laura Guédon
- Energy & Memory, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, Paris, France
| | - Coraline Desnous
- Energy & Memory, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, Paris, France
| | - Pierre-Yves Plaçais
- Energy & Memory, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, Paris, France.
| | - Thomas Preat
- Energy & Memory, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, Paris, France.
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8
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Nöbel S, Danchin E, Isabel G. Mate copying requires the coincidence detector Rutabaga in the mushroom bodies of Drosophila melanogaster. iScience 2023; 26:107682. [PMID: 37694137 PMCID: PMC10484988 DOI: 10.1016/j.isci.2023.107682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 07/03/2023] [Accepted: 08/14/2023] [Indexed: 09/12/2023] Open
Abstract
Mate choice constitutes a major fitness-affecting decision often involving social learning leading to copying the preference of other individuals (i.e., mate copying). While mate copying exists in many taxa, its underlying neurobiological mechanisms remain virtually unknown. Here, we show in Drosophila melanogaster that the rutabaga gene is necessary to support mate copying. Rutabaga encodes an adenylyl cyclase (AC-Rut+) acting as a coincidence detector in associative learning. Since the brain localization requirements for AC-Rut+ expression differ in classical and operant learning, we determine the functional localization of AC-Rut+ for mate copying by artificially rescuing the expression of AC-Rut+ in neural subsets of a rutabaga mutant. We found that AC-Rut+ has to be expressed in the mushroom bodies' Kenyon cells (KCs), specifically in the γ-KCs subset. Thus, this form of discriminative social learning requires the same KCs as non-social Pavlovian learning, suggesting that pathways of social and asocial learning overlap significantly.
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Affiliation(s)
- Sabine Nöbel
- Department of Zoology, Animal Ecology, Martin-Luther University Halle-Wittenberg, 06120 Halle (Saale), Germany
- Université Toulouse 1 Capitole and Institute for Advanced Study in Toulouse (IAST), Toulouse, France
- Laboratoire Évolution & Diversité Biologique (EDB UMR 5174), Université de Toulouse Midi-Pyrénées, CNRS, IRD, UPS, 118 route de Narbonne, 31062 Toulouse, France
| | - Etienne Danchin
- Laboratoire Évolution & Diversité Biologique (EDB UMR 5174), Université de Toulouse Midi-Pyrénées, CNRS, IRD, UPS, 118 route de Narbonne, 31062 Toulouse, France
- Centre de Recherches sur la Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), CNRS UMR 5169, Université de Toulouse Midi-Pyrénées, Toulouse, France
| | - Guillaume Isabel
- Centre de Recherches sur la Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), CNRS UMR 5169, Université de Toulouse Midi-Pyrénées, Toulouse, France
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9
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Chen CC, Lin HW, Feng KL, Tseng DW, de Belle JS, Chiang AS. A subset of cholinergic mushroom body neurons blocks long-term memory formation in Drosophila. Cell Rep 2023; 42:112974. [PMID: 37590142 DOI: 10.1016/j.celrep.2023.112974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2022] [Revised: 12/22/2022] [Accepted: 07/29/2023] [Indexed: 08/19/2023] Open
Abstract
Long-term memory (LTM) requires learning-induced synthesis of new proteins allocated to specific neurons and synapses in a neural circuit. Not all learned information, however, becomes permanent memory. How the brain gates relevant information into LTM remains unclear. In Drosophila adults, weak learning after a single training session in an olfactory aversive task typically does not induce protein-synthesis-dependent LTM. Instead, strong learning after multiple spaced training sessions is required. Here, we report that pre-synaptic active-zone protein synthesis and cholinergic signaling from the early α/β subset of mushroom body (MB) neurons produce a downstream inhibitory effect on LTM formation. When we eliminated inhibitory signaling from these neurons, weak learning was then sufficient to form LTM. This bidirectional circuit mechanism modulates the transition between distinct memory phase functions in different subpopulations of MB neurons in the olfactory memory circuit.
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Affiliation(s)
- Chun-Chao Chen
- Brain Research Center, National Tsing Hua University, Hsinchu 30013, Taiwan.
| | - Hsuan-Wen Lin
- Brain Research Center, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Kuan-Lin Feng
- Brain Research Center, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Der-Wan Tseng
- Brain Research Center, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - J Steven de Belle
- Brain Research Center, National Tsing Hua University, Hsinchu 30013, Taiwan; School of Life Sciences, Arizona State University, Tempe, AZ 85281, USA; Department of Psychological Sciences, University of San Diego, San Diego, CA 92110, USA; School of Life Sciences, University of Nevada, Las Vegas, NV 89154, USA; MnemOdyssey LLC, Escondido, CA 92027, USA
| | - Ann-Shyn Chiang
- Brain Research Center, National Tsing Hua University, Hsinchu 30013, Taiwan; Institute of Systems Neuroscience and Department of Life Science, National Tsing Hua University, Hsinchu 30013, Taiwan; Department of Biomedical Science and Environmental Biology, Kaohsiung Medical University, Kaohsiung 80780, Taiwan; Institute of Molecular and Genomic Medicine, National Health Research Institutes, Miaoli 35053, Taiwan; Graduate Institute of Clinical Medical Science, China Medical University, Taichung 40402, Taiwan; Kavli Institute for Brain and Mind, University of California at San Diego, La Jolla, CA 92093-0526, USA.
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10
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Shen P, Wan X, Wu F, Shi K, Li J, Gao H, Zhao L, Zhou C. Neural circuit mechanisms linking courtship and reward in Drosophila males. Curr Biol 2023; 33:2034-2050.e8. [PMID: 37160122 DOI: 10.1016/j.cub.2023.04.041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Revised: 03/15/2023] [Accepted: 04/17/2023] [Indexed: 05/11/2023]
Abstract
Courtship has evolved to achieve reproductive success in animal species. However, whether courtship itself has a positive value remains unclear. In the present work, we report that courtship is innately rewarding and can induce the expression of appetitive short-term memory (STM) and long-term memory (LTM) in Drosophila melanogaster males. Activation of male-specific P1 neurons is sufficient to mimic courtship-induced preference and memory performance. Surprisingly, P1 neurons functionally connect to a large proportion of dopaminergic neurons (DANs) in the protocerebral anterior medial (PAM) cluster. The acquisition of STM and LTM depends on two distinct subsets of PAM DANs that convey the courtship-reward signal to the restricted regions of the mushroom body (MB) γ and α/β lobes through two dopamine receptors, D1-like Dop1R1 and D2-like Dop2R. Furthermore, the retrieval of STM stored in the MB α'/β' lobes and LTM stored in the MB α/β lobe relies on two distinct MB output neurons. Finally, LTM consolidation requires two subsets of PAM DANs projecting to the MB α/β lobe and corresponding MB output neurons. Taken together, our findings demonstrate that courtship is a potent rewarding stimulus and reveal the underlying neural circuit mechanisms linking courtship and reward in Drosophila males.
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Affiliation(s)
- Peng Shen
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China; CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Xiaolu Wan
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China; CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Fengming Wu
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Kai Shi
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China; CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jing Li
- Institute of Molecular Physiology, Shenzhen Bay Laboratory, Shenzhen 518132, China
| | - Hongjiang Gao
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Lilin Zhao
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China; CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Chuan Zhou
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China; CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing 100049, China; Institute of Molecular Physiology, Shenzhen Bay Laboratory, Shenzhen 518132, China
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11
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Hafez OA, Escribano B, Ziegler RL, Hirtz JJ, Niebur E, Pielage J. The cellular architecture of memory modules in Drosophila supports stochastic input integration. eLife 2023; 12:e77578. [PMID: 36916672 PMCID: PMC10069864 DOI: 10.7554/elife.77578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 03/09/2023] [Indexed: 03/16/2023] Open
Abstract
The ability to associate neutral stimuli with valence information and to store these associations as memories forms the basis for decision making. To determine the underlying computational principles, we build a realistic computational model of a central decision module within the Drosophila mushroom body (MB), the fly's center for learning and memory. Our model combines the electron microscopy-based architecture of one MB output neuron (MBON-α3), the synaptic connectivity of its 948 presynaptic Kenyon cells (KCs), and its membrane properties obtained from patch-clamp recordings. We show that this neuron is electrotonically compact and that synaptic input corresponding to simulated odor input robustly drives its spiking behavior. Therefore, sparse innervation by KCs can efficiently control and modulate MBON activity in response to learning with minimal requirements on the specificity of synaptic localization. This architecture allows efficient storage of large numbers of memories using the flexible stochastic connectivity of the circuit.
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Affiliation(s)
- Omar A Hafez
- Zanvyl Krieger Mind/Brain Institute, Johns Hopkins UniversityBaltimoreUnited States
| | - Benjamin Escribano
- Division of Neurobiology and Zoology, Department of Biology, University of KaiserslauternKaiserslauternGermany
| | - Rouven L Ziegler
- Division of Neurobiology and Zoology, Department of Biology, University of KaiserslauternKaiserslauternGermany
| | - Jan J Hirtz
- Physiology of Neuronal Networks Group, Department of Biology, University of KaiserslauternKaiserslauternGermany
| | - Ernst Niebur
- Zanvyl Krieger Mind/Brain Institute, Johns Hopkins UniversityBaltimoreUnited States
- Solomon Snyder Department of Neuroscience, Johns Hopkins UniversityBaltimoreUnited States
| | - Jan Pielage
- Division of Neurobiology and Zoology, Department of Biology, University of KaiserslauternKaiserslauternGermany
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12
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Lapraz F, Boutres C, Fixary-Schuster C, De Queiroz BR, Plaçais PY, Cerezo D, Besse F, Préat T, Noselli S. Asymmetric activity of NetrinB controls laterality of the Drosophila brain. Nat Commun 2023; 14:1052. [PMID: 36828820 PMCID: PMC9958012 DOI: 10.1038/s41467-023-36644-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 02/01/2023] [Indexed: 02/26/2023] Open
Abstract
Left-Right (LR) asymmetry of the nervous system is widespread across animals and is thought to be important for cognition and behaviour. But in contrast to visceral organ asymmetry, the genetic basis and function of brain laterality remain only poorly characterized. In this study, we performed RNAi screening to identify genes controlling brain asymmetry in Drosophila. We found that the conserved NetrinB (NetB) pathway is required for a small group of bilateral neurons to project asymmetrically into a pair of neuropils (Asymmetrical Bodies, AB) in the central brain in both sexes. While neurons project unilaterally into the right AB in wild-type flies, netB mutants show a bilateral projection phenotype and hence lose asymmetry. Developmental time course analysis reveals an initially bilateral connectivity, eventually resolving into a right asymmetrical circuit during metamorphosis, with the NetB pathway being required just prior symmetry breaking. We show using unilateral clonal analysis that netB activity is required specifically on the right side for neurons to innervate the right AB. We finally show that loss of NetB pathway activity leads to specific alteration of long-term memory, providing a functional link between asymmetrical circuitry determined by NetB and animal cognitive functions.
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Affiliation(s)
- F Lapraz
- Université Côte d'Azur, CNRS, Inserm, iBV, Nice, France.
| | - C Boutres
- Université Côte d'Azur, CNRS, Inserm, iBV, Nice, France
| | | | | | - P Y Plaçais
- Plasticité du Cerveau, UMR 8249, CNRS, ESPCI Paris, PSL Research University, Paris, France
| | - D Cerezo
- Université Côte d'Azur, CNRS, Inserm, iBV, Nice, France
| | - F Besse
- Université Côte d'Azur, CNRS, Inserm, iBV, Nice, France
| | - T Préat
- Plasticité du Cerveau, UMR 8249, CNRS, ESPCI Paris, PSL Research University, Paris, France
| | - S Noselli
- Université Côte d'Azur, CNRS, Inserm, iBV, Nice, France.
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13
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Turrel O, Ramesh N, Escher MJF, Pooryasin A, Sigrist SJ. Transient active zone remodeling in the Drosophila mushroom body supports memory. Curr Biol 2022; 32:4900-4913.e4. [PMID: 36327980 DOI: 10.1016/j.cub.2022.10.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 08/15/2022] [Accepted: 10/06/2022] [Indexed: 11/22/2022]
Abstract
Elucidating how the distinct components of synaptic plasticity dynamically orchestrate the distinct stages of memory acquisition and maintenance within neuronal networks remains a major challenge. Specifically, plasticity processes tuning the functional and also structural state of presynaptic active zone (AZ) release sites are widely observed in vertebrates and invertebrates, but their behavioral relevance remains mostly unclear. We here provide evidence that a transient upregulation of presynaptic AZ release site proteins supports aversive olfactory mid-term memory in the Drosophila mushroom body (MB). Upon paired aversive olfactory conditioning, AZ protein levels (ELKS-family BRP/(m)unc13-family release factor Unc13A) increased for a few hours with MB-lobe-specific dynamics. Kenyon cell (KC, intrinsic MB neurons)-specific knockdown (KD) of BRP did not affect aversive olfactory short-term memory (STM) but strongly suppressed aversive mid-term memory (MTM). Different proteins crucial for the transport of AZ biosynthetic precursors (transport adaptor Aplip1/Jip-1; kinesin motor IMAC/Unc104; small GTPase Arl8) were also specifically required for the formation of aversive olfactory MTM. Consistent with the merely transitory increase of AZ proteins, BRP KD did not interfere with the formation of aversive olfactory long-term memory (LTM; i.e., 1 day). Our data suggest that the remodeling of presynaptic AZ refines the MB circuitry after paired aversive conditioning, over a time window of a few hours, to display aversive olfactory memories.
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Affiliation(s)
- Oriane Turrel
- Institute for Biology/Genetics, Freie Universität Berlin, Takustrasse 6, 14195 Berlin, Germany
| | - Niraja Ramesh
- Institute for Biology/Genetics, Freie Universität Berlin, Takustrasse 6, 14195 Berlin, Germany
| | - Marc J F Escher
- Institute for Biology/Genetics, Freie Universität Berlin, Takustrasse 6, 14195 Berlin, Germany
| | - Atefeh Pooryasin
- Institute for Biology/Genetics, Freie Universität Berlin, Takustrasse 6, 14195 Berlin, Germany
| | - Stephan J Sigrist
- Institute for Biology/Genetics, Freie Universität Berlin, Takustrasse 6, 14195 Berlin, Germany; NeuroCure Cluster of Excellence, Charité Universitätsmedizin, Charitéplatz 1, 10117 Berlin, Germany.
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14
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Villar ME, Pavão-Delgado M, Amigo M, Jacob PF, Merabet N, Pinot A, Perry SA, Waddell S, Perisse E. Differential coding of absolute and relative aversive value in the Drosophila brain. Curr Biol 2022; 32:4576-4592.e5. [DOI: 10.1016/j.cub.2022.08.058] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 06/24/2022] [Accepted: 08/19/2022] [Indexed: 11/30/2022]
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15
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Bourouliti A, Skoulakis EMC. Anesthesia Resistant Memories in Drosophila, a Working Perspective. Int J Mol Sci 2022; 23:ijms23158527. [PMID: 35955662 PMCID: PMC9369046 DOI: 10.3390/ijms23158527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 07/28/2022] [Accepted: 07/29/2022] [Indexed: 12/10/2022] Open
Abstract
Memories are lasting representations over time of associations between stimuli or events. In general, the relatively slow consolidation of memories requires protein synthesis with a known exception being the so-called Anesthesia Resistant Memory (ARM) in Drosophila. This protein synthesis-independent memory type survives amnestic shocks after a short, sensitive window post training, and can also emerge after repeated cycles of training in a negatively reinforced olfactory conditioning task, without rest between cycles (massed conditioning—MC). We discussed operational and molecular mechanisms that mediate ARM and differentiate it from protein synthesis-dependent long-term memory (LTM) in Drosophila. Based on the notion that ARM is unlikely to specifically characterize Drosophila, we examined protein synthesis and MC-elicited memories in other species and based on intraspecies shared molecular components and proposed potential relationships of ARM with established memory types in Drosophila and vertebrates.
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Affiliation(s)
- Anna Bourouliti
- Institute for Fundamental Biomedical Research, Biomedical Sciences Research Center “Alexander Fleming”, 16674 Vari, Greece;
- Department of Molecular Biology and Genetics, Democritus University of Thrace, 68100 Alexandroupolis, Greece
| | - Efthimios M. C. Skoulakis
- Institute for Fundamental Biomedical Research, Biomedical Sciences Research Center “Alexander Fleming”, 16674 Vari, Greece;
- Correspondence:
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16
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Cold Shock Disrupts Massed Training-Elicited Memory in Drosophila. Int J Mol Sci 2022; 23:ijms23126407. [PMID: 35742852 PMCID: PMC9224184 DOI: 10.3390/ijms23126407] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 06/03/2022] [Accepted: 06/06/2022] [Indexed: 02/04/2023] Open
Abstract
Memory consolidation is a time-dependent process occurring over hours, days, or longer in different species and requires protein synthesis. An apparent exception is a memory type in Drosophila elicited by a single olfactory conditioning episode, which ostensibly consolidates quickly, rendering it resistant to disruption by cold anesthesia a few hours post-training. This anesthesia-resistant memory (ARM), is independent of protein synthesis. Protein synthesis independent memory can also be elicited in Drosophila by multiple massed cycles of olfactory conditioning, and this led to the prevailing notion that both of these operationally distinct training regimes yield ARM. Significantly, we show that, unlike bona fide ARM, massed conditioning-elicited memory remains sensitive to the amnestic treatment two hours post-training and hence it is not ARM. Therefore, there are two protein synthesis-independent memory types in Drosophila.
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17
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Abstract
This selective review explores biologically inspired learning as a model for intelligent robot control and sensing technology on the basis of specific examples. Hebbian synaptic learning is discussed as a functionally relevant model for machine learning and intelligence, as explained on the basis of examples from the highly plastic biological neural networks of invertebrates and vertebrates. Its potential for adaptive learning and control without supervision, the generation of functional complexity, and control architectures based on self-organization is brought forward. Learning without prior knowledge based on excitatory and inhibitory neural mechanisms accounts for the process through which survival-relevant or task-relevant representations are either reinforced or suppressed. The basic mechanisms of unsupervised biological learning drive synaptic plasticity and adaptation for behavioral success in living brains with different levels of complexity. The insights collected here point toward the Hebbian model as a choice solution for “intelligent” robotics and sensor systems.
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18
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Smith MAY, Honegger KS, Turner G, de Bivort B. Idiosyncratic learning performance in flies. Biol Lett 2022; 18:20210424. [PMID: 35104427 PMCID: PMC8807056 DOI: 10.1098/rsbl.2021.0424] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 12/21/2021] [Indexed: 11/18/2022] Open
Abstract
Individuals vary in their innate behaviours, even when they have the same genome and have been reared in the same environment. The extent of individuality in plastic behaviours, like learning, is less well characterized. Also unknown is the extent to which intragenotypic differences in learning generalize: if an individual performs well in one assay, will it perform well in other assays? We investigated this using the fruit fly Drosophila melanogaster, an organism long-used to study the mechanistic basis of learning and memory. We found that isogenic flies, reared in identical laboratory conditions, and subject to classical conditioning that associated odorants with electric shock, exhibit clear individuality in their learning responses. Flies that performed well when an odour was paired with shock tended to perform well when the odour was paired with bitter taste or when other odours were paired with shock. Thus, individuality in learning performance appears to be prominent in isogenic animals reared identically, and individual differences in learning performance generalize across some aversive sensory modalities. Establishing these results in flies opens up the possibility of studying the genetic and neural circuit basis of individual differences in learning in a highly suitable model organism.
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Affiliation(s)
- Matthew A.-Y. Smith
- Department of Organismic and Evolutionary Biology and Center for Brain Science, Harvard University, Cambridge, MA 02138, USA
| | - Kyle S. Honegger
- Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago, IL 60611, USA
| | - Glenn Turner
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Benjamin de Bivort
- Department of Organismic and Evolutionary Biology and Center for Brain Science, Harvard University, Cambridge, MA 02138, USA
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19
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Devineni AV, Scaplen KM. Neural Circuits Underlying Behavioral Flexibility: Insights From Drosophila. Front Behav Neurosci 2022; 15:821680. [PMID: 35069145 PMCID: PMC8770416 DOI: 10.3389/fnbeh.2021.821680] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 12/14/2021] [Indexed: 11/16/2022] Open
Abstract
Behavioral flexibility is critical to survival. Animals must adapt their behavioral responses based on changes in the environmental context, internal state, or experience. Studies in Drosophila melanogaster have provided insight into the neural circuit mechanisms underlying behavioral flexibility. Here we discuss how Drosophila behavior is modulated by internal and behavioral state, environmental context, and learning. We describe general principles of neural circuit organization and modulation that underlie behavioral flexibility, principles that are likely to extend to other species.
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Affiliation(s)
- Anita V. Devineni
- Department of Biology, Emory University, Atlanta, GA, United States
- Zuckerman Mind Brain Institute, Columbia University, New York, NY, United States
| | - Kristin M. Scaplen
- Department of Psychology, Bryant University, Smithfield, RI, United States
- Center for Health and Behavioral Studies, Bryant University, Smithfield, RI, United States
- Department of Neuroscience, Brown University, Providence, RI, United States
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20
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Piao C, Sigrist SJ. (M)Unc13s in Active Zone Diversity: A Drosophila Perspective. Front Synaptic Neurosci 2022; 13:798204. [PMID: 35046788 PMCID: PMC8762327 DOI: 10.3389/fnsyn.2021.798204] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 11/29/2021] [Indexed: 12/03/2022] Open
Abstract
The so-called active zones at pre-synaptic terminals are the ultimate filtering devices, which couple between action potential frequency and shape, and the information transferred to the post-synaptic neurons, finally tuning behaviors. Within active zones, the release of the synaptic vesicle operates from specialized “release sites.” The (M)Unc13 class of proteins is meant to define release sites topologically and biochemically, and diversity between Unc13-type release factor isoforms is suspected to steer diversity at active zones. The two major Unc13-type isoforms, namely, Unc13A and Unc13B, have recently been described from the molecular to the behavioral level, exploiting Drosophila being uniquely suited to causally link between these levels. The exact nanoscale distribution of voltage-gated Ca2+ channels relative to release sites (“coupling”) at pre-synaptic active zones fundamentally steers the release of the synaptic vesicle. Unc13A and B were found to be either tightly or loosely coupled across Drosophila synapses. In this review, we reported recent findings on diverse aspects of Drosophila Unc13A and B, importantly, their nano-topological distribution at active zones and their roles in release site generation, active zone assembly, and pre-synaptic homeostatic plasticity. We compared their stoichiometric composition at different synapse types, reviewing the correlation between nanoscale distribution of these two isoforms and release physiology and, finally, discuss how isoform-specific release components might drive the functional heterogeneity of synapses and encode discrete behavior.
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Affiliation(s)
- Chengji Piao
- Institute for Biology/Genetics, Freie Universität Berlin, Berlin, Germany
- NeuroCure Cluster of Excellence, Charité Universitätsmedizin, Berlin, Germany
| | - Stephan J. Sigrist
- Institute for Biology/Genetics, Freie Universität Berlin, Berlin, Germany
- NeuroCure Cluster of Excellence, Charité Universitätsmedizin, Berlin, Germany
- *Correspondence: Stephan J. Sigrist
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21
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Pribbenow C, Chen YC, Heim MM, Laber D, Reubold S, Reynolds E, Balles I, Fernández-d V Alquicira T, Suárez-Grimalt R, Scheunemann L, Rauch C, Matkovic T, Rösner J, Lichtner G, Jagannathan SR, Owald D. Postsynaptic plasticity of cholinergic synapses underlies the induction and expression of appetitive and familiarity memories in Drosophila. eLife 2022; 11:80445. [PMID: 36250621 PMCID: PMC9733945 DOI: 10.7554/elife.80445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 10/17/2022] [Indexed: 12/14/2022] Open
Abstract
In vertebrates, several forms of memory-relevant synaptic plasticity involve postsynaptic rearrangements of glutamate receptors. In contrast, previous work indicates that Drosophila and other invertebrates store memories using presynaptic plasticity of cholinergic synapses. Here, we provide evidence for postsynaptic plasticity at cholinergic output synapses from the Drosophila mushroom bodies (MBs). We find that the nicotinic acetylcholine receptor (nAChR) subunit α5 is required within specific MB output neurons for appetitive memory induction but is dispensable for aversive memories. In addition, nAChR α2 subunits mediate memory expression and likely function downstream of α5 and the postsynaptic scaffold protein discs large (Dlg). We show that postsynaptic plasticity traces can be induced independently of the presynapse, and that in vivo dynamics of α2 nAChR subunits are changed both in the context of associative and non-associative (familiarity) memory formation, underlying different plasticity rules. Therefore, regardless of neurotransmitter identity, key principles of postsynaptic plasticity support memory storage across phyla.
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Affiliation(s)
- Carlotta Pribbenow
- Institute of Neurophysiology, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of HealthBerlinGermany
| | - Yi-chun Chen
- Institute of Neurophysiology, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of HealthBerlinGermany
| | - M-Marcel Heim
- Institute of Neurophysiology, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of HealthBerlinGermany
| | - Desiree Laber
- Institute of Neurophysiology, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of HealthBerlinGermany
| | - Silas Reubold
- Institute of Neurophysiology, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of HealthBerlinGermany
| | - Eric Reynolds
- Institute of Neurophysiology, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of HealthBerlinGermany
| | - Isabella Balles
- Institute of Neurophysiology, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of HealthBerlinGermany
| | - Tania Fernández-d V Alquicira
- Institute of Neurophysiology, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of HealthBerlinGermany
| | - Raquel Suárez-Grimalt
- Institute of Neurophysiology, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of HealthBerlinGermany,Einstein Center for Neurosciences BerlinBerlinGermany
| | - Lisa Scheunemann
- Institute of Neurophysiology, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of HealthBerlinGermany,NeuroCure, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of HealthBerlinGermany,Institut für Biologie, Freie Universität BerlinBerlinGermany
| | - Carolin Rauch
- Institute of Neurophysiology, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of HealthBerlinGermany
| | - Tanja Matkovic
- Institut für Biologie, Freie Universität BerlinBerlinGermany
| | - Jörg Rösner
- NWFZ, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of HealthGreifswaldGermany
| | - Gregor Lichtner
- Institute of Neurophysiology, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of HealthBerlinGermany,Universitätsmedizin Greifswald, Department of Anesthesia, Critical Care, Emergency and Pain MedicineGreifswaldGermany
| | - Sridhar R Jagannathan
- Institute of Neurophysiology, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of HealthBerlinGermany
| | - David Owald
- Institute of Neurophysiology, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of HealthBerlinGermany,Einstein Center for Neurosciences BerlinBerlinGermany,NeuroCure, Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, and Berlin Institute of HealthBerlinGermany
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22
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Feng KL, Weng JY, Chen CC, Abubaker MB, Lin HW, Charng CC, Lo CC, de Belle JS, Tully T, Lien CC, Chiang AS. Neuropeptide F inhibits dopamine neuron interference of long-term memory consolidation in Drosophila. iScience 2021; 24:103506. [PMID: 34934925 DOI: 10.1016/j.isci.2021.103506] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 09/13/2021] [Accepted: 11/22/2021] [Indexed: 11/28/2022] Open
Abstract
Long-term memory (LTM) formation requires consolidation processes to overcome interfering signals that erode memory formation. Olfactory memory in Drosophila involves convergent projection neuron (PN; odor) and dopaminergic neuron (DAN; reinforcement) input to the mushroom body (MB). How post-training DAN activity in the posterior lateral protocerebrum (PPL1) continues to regulate memory consolidation remains unknown. Here we address this question using targeted transgenes in behavior and electrophysiology experiments to show that (1) persistent post-training activity of PPL1-α2α'2 and PPL1-α3 DANs interferes with aversive LTM formation; (2) neuropeptide F (NPF) signaling blocks this interference in PPL1-α2α'2 and PPL1-α3 DANs after spaced training to enable LTM formation; and (3) training-induced NPF release and neurotransmission from two upstream dorsal-anterior-lateral (DAL2) neurons are required to form LTM. Thus, NPF signals from DAL2 neurons to specific PPL1 DANs disinhibit the memory circuit, ensuring that periodic events are remembered as consolidated LTM.
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Affiliation(s)
- Kuan-Lin Feng
- Institute of Biotechnology, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Ju-Yun Weng
- Brain Research Center, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Chun-Chao Chen
- Brain Research Center, National Tsing Hua University, Hsinchu 30013, Taiwan
| | | | - Hsuan-Wen Lin
- Brain Research Center, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Ching-Che Charng
- Institute of Systems Neuroscience and Department of Life Science, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Chung-Chuan Lo
- Brain Research Center, National Tsing Hua University, Hsinchu 30013, Taiwan.,Institute of Systems Neuroscience and Department of Life Science, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - J Steven de Belle
- Brain Research Center, National Tsing Hua University, Hsinchu 30013, Taiwan.,Department of Psychological Sciences, University of San Diego, San Diego, CA 92110, USA.,School of Life Sciences, University of Nevada, Las Vegas, NV 89154, USA.,MnemOdyssey LLC, Escondido, CA 92027, USA
| | - Tim Tully
- Institute of Biotechnology, National Tsing Hua University, Hsinchu 30013, Taiwan.,Brain Research Center, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Cheng-Chang Lien
- Institute of Neuroscience and Brain Research Center, National Yang Ming Chiao Tung University, Taipei 11221, Taiwan
| | - Ann-Shyn Chiang
- Institute of Biotechnology, National Tsing Hua University, Hsinchu 30013, Taiwan.,Brain Research Center, National Tsing Hua University, Hsinchu 30013, Taiwan.,Institute of Systems Neuroscience and Department of Life Science, National Tsing Hua University, Hsinchu 30013, Taiwan.,Kaohsiung Medical University, Kaohsiung 80708, Taiwan.,National Health Research Institutes, Zhunan 35053, Taiwan.,China Medical University, Taichung 40402, Taiwan.,Kavli Institute for Brain and Mind, University of California at San Diego, La Jolla, CA 92093-0526, USA
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23
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Eschbach C, Fushiki A, Winding M, Afonso B, Andrade IV, Cocanougher BT, Eichler K, Gepner R, Si G, Valdes-Aleman J, Fetter RD, Gershow M, Jefferis GS, Samuel AD, Truman JW, Cardona A, Zlatic M. Circuits for integrating learned and innate valences in the insect brain. eLife 2021; 10:62567. [PMID: 34755599 PMCID: PMC8616581 DOI: 10.7554/elife.62567] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 11/03/2021] [Indexed: 12/23/2022] Open
Abstract
Animal behavior is shaped both by evolution and by individual experience. Parallel brain pathways encode innate and learned valences of cues, but the way in which they are integrated during action-selection is not well understood. We used electron microscopy to comprehensively map with synaptic resolution all neurons downstream of all mushroom body (MB) output neurons (encoding learned valences) and characterized their patterns of interaction with lateral horn (LH) neurons (encoding innate valences) in Drosophila larva. The connectome revealed multiple convergence neuron types that receive convergent MB and LH inputs. A subset of these receives excitatory input from positive-valence MB and LH pathways and inhibitory input from negative-valence MB pathways. We confirmed functional connectivity from LH and MB pathways and behavioral roles of two of these neurons. These neurons encode integrated odor value and bidirectionally regulate turning. Based on this, we speculate that learning could potentially skew the balance of excitation and inhibition onto these neurons and thereby modulate turning. Together, our study provides insights into the circuits that integrate learned and innate valences to modify behavior.
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Affiliation(s)
- Claire Eschbach
- HHMI Janelia Research Campus, Richmond, United Kingdom.,Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom.,Department of Zoology, University of Cambridge, Cambridge, United Kingdom
| | - Akira Fushiki
- HHMI Janelia Research Campus, Richmond, United Kingdom.,Department of Neuroscience & Neurology, & Zuckerman Mind Brain Institute, Columbia University, New York, United States
| | - Michael Winding
- HHMI Janelia Research Campus, Richmond, United Kingdom.,Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom.,Department of Zoology, University of Cambridge, Cambridge, United Kingdom
| | - Bruno Afonso
- HHMI Janelia Research Campus, Richmond, United Kingdom
| | - Ingrid V Andrade
- HHMI Janelia Research Campus, Richmond, United Kingdom.,Department of Molecular, Cell and Developmental Biology, University California Los Angeles, Los Angeles, United States
| | - Benjamin T Cocanougher
- HHMI Janelia Research Campus, Richmond, United Kingdom.,Department of Zoology, University of Cambridge, Cambridge, United Kingdom
| | - Katharina Eichler
- HHMI Janelia Research Campus, Richmond, United Kingdom.,Department of Zoology, University of Cambridge, Cambridge, United Kingdom
| | - Ruben Gepner
- Department of Physics, New York University, New York, United States
| | - Guangwei Si
- Department of Physics, Harvard University, Cambridge, United States.,Center for Brain Science, Harvard University, Cambridge, United States
| | - Javier Valdes-Aleman
- HHMI Janelia Research Campus, Richmond, United Kingdom.,Department of Zoology, University of Cambridge, Cambridge, United Kingdom.,Department of Molecular, Cell and Developmental Biology, University California Los Angeles, Los Angeles, United States
| | | | - Marc Gershow
- Department of Physics, New York University, New York, United States.,Center for Neural Science, New York University, New York, United States.,Neuroscience Institute, New York University, New York, United States
| | - Gregory Sxe Jefferis
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom.,Department of Zoology, University of Cambridge, Cambridge, United Kingdom
| | - Aravinthan Dt Samuel
- Department of Physics, Harvard University, Cambridge, United States.,Center for Brain Science, Harvard University, Cambridge, United States
| | - James W Truman
- HHMI Janelia Research Campus, Richmond, United Kingdom.,Department of Biology, University of Washington, Seattle, United States
| | - Albert Cardona
- HHMI Janelia Research Campus, Richmond, United Kingdom.,Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom.,Department of Physiology, Development & Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Marta Zlatic
- HHMI Janelia Research Campus, Richmond, United Kingdom.,Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom.,Department of Zoology, University of Cambridge, Cambridge, United Kingdom
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24
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Lesar A, Tahir J, Wolk J, Gershow M. Switch-like and persistent memory formation in individual Drosophila larvae. eLife 2021; 10:e70317. [PMID: 34636720 PMCID: PMC8510578 DOI: 10.7554/elife.70317] [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: 05/13/2021] [Accepted: 08/27/2021] [Indexed: 11/15/2022] Open
Abstract
Associative learning allows animals to use past experience to predict future events. The circuits underlying memory formation support immediate and sustained changes in function, often in response to a single example. Larval Drosophila is a genetic model for memory formation that can be accessed at molecular, synaptic, cellular, and circuit levels, often simultaneously, but existing behavioral assays for larval learning and memory do not address individual animals, and it has been difficult to form long-lasting memories, especially those requiring synaptic reorganization. We demonstrate a new assay for learning and memory capable of tracking the changing preferences of individual larvae. We use this assay to explore how activation of a pair of reward neurons changes the response to the innately aversive gas carbon dioxide (CO2). We confirm that when coupled to CO2 presentation in appropriate temporal sequence, optogenetic reward reduces avoidance of CO2. We find that learning is switch-like: all-or-none and quantized in two states. Memories can be extinguished by repeated unrewarded exposure to CO2 but are stabilized against extinction by repeated training or overnight consolidation. Finally, we demonstrate long-lasting protein synthesis dependent and independent memory formation.
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Affiliation(s)
- Amanda Lesar
- Department of Physics, New York UniversityNew YorkUnited States
| | - Javan Tahir
- Department of Physics, New York UniversityNew YorkUnited States
| | - Jason Wolk
- Department of Physics, New York UniversityNew YorkUnited States
| | - Marc Gershow
- Department of Physics, New York UniversityNew YorkUnited States
- Center for Neural Science, New York UniversityNew YorkUnited States
- NYU Neuroscience Institute, New York University Langone Medical CenterNew YorkUnited States
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25
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Zhao B, Sun J, Li Q, Zhong Y. Differential conditioning produces merged long-term memory in Drosophila. eLife 2021; 10:66499. [PMID: 34279222 PMCID: PMC8346281 DOI: 10.7554/elife.66499] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 07/18/2021] [Indexed: 11/29/2022] Open
Abstract
Multiple spaced trials of aversive differential conditioning can produce two independent long-term memories (LTMs) of opposite valence. One is an aversive memory for avoiding the conditioned stimulus (CS+), and the other is a safety memory for approaching the non-conditioned stimulus (CS–). Here, we show that a single trial of aversive differential conditioning yields one merged LTM (mLTM) for avoiding both CS+ and CS–. Such mLTM can be detected after sequential exposures to the shock-paired CS+ and -unpaired CS–, and be retrieved by either CS+ or CS–. The formation of mLTM relies on triggering aversive-reinforcing dopaminergic neurons and subsequent new protein synthesis. Expressing mLTM involves αβ Kenyon cells and corresponding approach-directing mushroom body output neurons, in which similar-amplitude long-term depression of responses to CS+ and CS– seems to signal the mLTM. Our results suggest that animals can develop distinct strategies for occasional and repeated threatening experiences.
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Affiliation(s)
- Bohan Zhao
- School of Life Sciences, IDG/McGovern Institute for Brain Research, and MOE Key Laboratory for Protein Science, Tsinghua University, Beijing, China.,Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Jiameng Sun
- School of Life Sciences, IDG/McGovern Institute for Brain Research, and MOE Key Laboratory for Protein Science, Tsinghua University, Beijing, China.,Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Qian Li
- School of Life Sciences, IDG/McGovern Institute for Brain Research, and MOE Key Laboratory for Protein Science, Tsinghua University, Beijing, China.,Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Yi Zhong
- School of Life Sciences, IDG/McGovern Institute for Brain Research, and MOE Key Laboratory for Protein Science, Tsinghua University, Beijing, China.,Tsinghua-Peking Center for Life Sciences, Beijing, China
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26
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Jacob PF, Vargas-Gutierrez P, Okray Z, Vietti-Michelina S, Felsenberg J, Waddell S. Prior experience conditionally inhibits the expression of new learning in Drosophila. Curr Biol 2021; 31:3490-3503.e3. [PMID: 34146482 PMCID: PMC8409488 DOI: 10.1016/j.cub.2021.05.056] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 04/29/2021] [Accepted: 05/26/2021] [Indexed: 11/19/2022]
Abstract
Prior experience of a stimulus can inhibit subsequent acquisition or expression of a learned association of that stimulus. However, the neuronal manifestations of this learning effect, named latent inhibition (LI), are poorly understood. Here, we show that prior odor exposure can produce context-dependent LI of later appetitive olfactory memory performance in Drosophila. Odor pre-exposure forms a short-lived aversive memory whose lone expression lacks context-dependence. Acquisition of odor pre-exposure memory requires aversively reinforcing dopaminergic neurons that innervate two mushroom body compartments—one group of which exhibits increasing activity with successive odor experience. Odor-specific responses of the corresponding mushroom body output neurons are suppressed, and their output is necessary for expression of both pre-exposure memory and LI of appetitive memory. Therefore, odor pre-exposure attaches negative valence to the odor itself, and LI of appetitive memory results from a temporary and context-dependent retrieval deficit imposed by competition with the parallel short-lived aversive memory. Odor pre-exposure alters the expression of a learned association of that odor Pre-exposure memory only affects subsequent retrieval if context is consistent Pre-exposure memory can complement or compete with a learned association Odor pre-exposure forms a labile mushroom body-dependent aversive memory
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Affiliation(s)
- Pedro F Jacob
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford OX1 3TA, UK
| | | | - Zeynep Okray
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford OX1 3TA, UK
| | | | - Johannes Felsenberg
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford OX1 3TA, UK
| | - Scott Waddell
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford OX1 3TA, UK.
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27
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Adel M, Griffith LC. The Role of Dopamine in Associative Learning in Drosophila: An Updated Unified Model. Neurosci Bull 2021; 37:831-852. [PMID: 33779893 PMCID: PMC8192648 DOI: 10.1007/s12264-021-00665-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 09/25/2020] [Indexed: 10/21/2022] Open
Abstract
Learning to associate a positive or negative experience with an unrelated cue after the presentation of a reward or a punishment defines associative learning. The ability to form associative memories has been reported in animal species as complex as humans and as simple as insects and sea slugs. Associative memory has even been reported in tardigrades [1], species that diverged from other animal phyla 500 million years ago. Understanding the mechanisms of memory formation is a fundamental goal of neuroscience research. In this article, we work on resolving the current contradictions between different Drosophila associative memory circuit models and propose an updated version of the circuit model that predicts known memory behaviors that current models do not. Finally, we propose a model for how dopamine may function as a reward prediction error signal in Drosophila, a dopamine function that is well-established in mammals but not in insects [2, 3].
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Affiliation(s)
- Mohamed Adel
- Department of Biology, Volen National Center for Complex Systems and National Center for Behavioral Genomics, Brandeis University, Waltham, MA, 02454-9110, USA.
| | - Leslie C Griffith
- Department of Biology, Volen National Center for Complex Systems and National Center for Behavioral Genomics, Brandeis University, Waltham, MA, 02454-9110, USA
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28
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Bennett JEM, Philippides A, Nowotny T. Learning with reinforcement prediction errors in a model of the Drosophila mushroom body. Nat Commun 2021; 12:2569. [PMID: 33963189 PMCID: PMC8105414 DOI: 10.1038/s41467-021-22592-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 03/16/2021] [Indexed: 02/03/2023] Open
Abstract
Effective decision making in a changing environment demands that accurate predictions are learned about decision outcomes. In Drosophila, such learning is orchestrated in part by the mushroom body, where dopamine neurons signal reinforcing stimuli to modulate plasticity presynaptic to mushroom body output neurons. Building on previous mushroom body models, in which dopamine neurons signal absolute reinforcement, we propose instead that dopamine neurons signal reinforcement prediction errors by utilising feedback reinforcement predictions from output neurons. We formulate plasticity rules that minimise prediction errors, verify that output neurons learn accurate reinforcement predictions in simulations, and postulate connectivity that explains more physiological observations than an experimentally constrained model. The constrained and augmented models reproduce a broad range of conditioning and blocking experiments, and we demonstrate that the absence of blocking does not imply the absence of prediction error dependent learning. Our results provide five predictions that can be tested using established experimental methods.
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Affiliation(s)
- James E. M. Bennett
- grid.12082.390000 0004 1936 7590Department of Informatics, University of Sussex, Brighton, UK
| | - Andrew Philippides
- grid.12082.390000 0004 1936 7590Department of Informatics, University of Sussex, Brighton, UK
| | - Thomas Nowotny
- grid.12082.390000 0004 1936 7590Department of Informatics, University of Sussex, Brighton, UK
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29
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Springer M, Nawrot MP. A Mechanistic Model for Reward Prediction and Extinction Learning in the Fruit Fly. eNeuro 2021; 8:ENEURO.0549-20.2021. [PMID: 33785523 PMCID: PMC8211469 DOI: 10.1523/eneuro.0549-20.2021] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 03/15/2021] [Accepted: 03/18/2021] [Indexed: 01/08/2023] Open
Abstract
Extinction learning, the ability to update previously learned information by integrating novel contradictory information, is of high clinical relevance for therapeutic approaches to the modulation of maladaptive memories. Insect models have been instrumental in uncovering fundamental processes of memory formation and memory update. Recent experimental results in Drosophila melanogaster suggest that, after the behavioral extinction of a memory, two parallel but opposing memory traces coexist, residing at different sites within the mushroom body (MB). Here, we propose a minimalistic circuit model of the Drosophila MB that supports classical appetitive and aversive conditioning and memory extinction. The model is tailored to the existing anatomic data and involves two circuit motives of central functional importance. It employs plastic synaptic connections between Kenyon cells (KCs) and MB output neurons (MBONs) in separate and mutually inhibiting appetitive and aversive learning pathways. Recurrent modulation of plasticity through projections from MBONs to reinforcement-mediating dopaminergic neurons (DAN) implements a simple reward prediction mechanism. A distinct set of four MBONs encodes odor valence and predicts behavioral model output. Subjecting our model to learning and extinction protocols reproduced experimental results from recent behavioral and imaging studies. Simulating the experimental blocking of synaptic output of individual neurons or neuron groups in the model circuit confirmed experimental results and allowed formulation of testable predictions. In the temporal domain, our model achieves rapid learning with a step-like increase in the encoded odor value after a single pairing of the conditioned stimulus (CS) with a reward or punishment, facilitating single-trial learning.
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Affiliation(s)
- Magdalena Springer
- Computational Systems Neuroscience, Institute of Zoology, University of Cologne, Biocenter, Cologne 50674, Germany
| | - Martin Paul Nawrot
- Computational Systems Neuroscience, Institute of Zoology, University of Cologne, Biocenter, Cologne 50674, Germany
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30
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Roselli C, Ramaswami M, Boto T, Cervantes-Sandoval I. The Making of Long-Lasting Memories: A Fruit Fly Perspective. Front Behav Neurosci 2021; 15:662129. [PMID: 33859556 PMCID: PMC8042140 DOI: 10.3389/fnbeh.2021.662129] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 03/08/2021] [Indexed: 11/25/2022] Open
Abstract
Understanding the nature of the molecular mechanisms underlying memory formation, consolidation, and forgetting are some of the fascinating questions in modern neuroscience. The encoding, stabilization and elimination of memories, rely on the structural reorganization of synapses. These changes will enable the facilitation or depression of neural activity in response to the acquisition of new information. In other words, these changes affect the weight of specific nodes within a neural network. We know that these plastic reorganizations require de novo protein synthesis in the context of Long-term memory (LTM). This process depends on neural activity triggered by the learned experience. The use of model organisms like Drosophila melanogaster has been proven essential for advancing our knowledge in the field of neuroscience. Flies offer an optimal combination of a more straightforward nervous system, composed of a limited number of cells, and while still displaying complex behaviors. Studies in Drosophila neuroscience, which expanded over several decades, have been critical for understanding the cellular and molecular mechanisms leading to the synaptic and behavioral plasticity occurring in the context of learning and memory. This is possible thanks to sophisticated technical approaches that enable precise control of gene expression in the fruit fly as well as neural manipulation, like chemogenetics, thermogenetics, or optogenetics. The search for the identity of genes expressed as a result of memory acquisition has been an active interest since the origins of behavioral genetics. From screenings of more or less specific candidates to broader studies based on transcriptome analysis, our understanding of the genetic control behind LTM has expanded exponentially in the past years. Here we review recent literature regarding how the formation of memories induces a rapid, extensive and, in many cases, transient wave of transcriptional activity. After a consolidation period, transcriptome changes seem more stable and likely represent the synthesis of new proteins. The complexity of the circuitry involved in memory formation and consolidation is such that there are localized changes in neural activity, both regarding temporal dynamics and the nature of neurons and subcellular locations affected, hence inducing specific temporal and localized changes in protein expression. Different types of neurons are recruited at different times into memory traces. In LTM, the synthesis of new proteins is required in specific subsets of cells. This de novo translation can take place in the somatic cytoplasm and/or locally in distinct zones of compartmentalized synaptic activity, depending on the nature of the proteins and the plasticity-inducing processes that occur. We will also review recent advances in understanding how localized changes are confined to the relevant synapse. These recent studies have led to exciting discoveries regarding proteins that were not previously involved in learning and memory processes. This invaluable information will lead to future functional studies on the roles that hundreds of new molecular actors play in modulating neural activity.
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Affiliation(s)
- Camilla Roselli
- Trinity College Institute of Neuroscience, School of Genetics and Microbiology, Smurfit Institute of Genetics and School of Natural Sciences, Trinity College Dublin, Dublin, Ireland
| | - Mani Ramaswami
- Trinity College Institute of Neuroscience, School of Genetics and Microbiology, Smurfit Institute of Genetics and School of Natural Sciences, Trinity College Dublin, Dublin, Ireland.,National Centre for Biological Sciences, TIFR, Bengaluru, India
| | - Tamara Boto
- Trinity College Institute of Neuroscience, Department of Physiology, School of Medicine, Trinity College Dublin, Dublin, Ireland
| | - Isaac Cervantes-Sandoval
- Department of Biology, Georgetown University, Washington, DC, United States.,Interdisciplinary Program in Neuroscience, Georgetown University, Washington, DC, United States
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31
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Muria A, Musso PY, Durrieu M, Portugal FR, Ronsin B, Gordon MD, Jeanson R, Isabel G. Social facilitation of long-lasting memory is mediated by CO 2 in Drosophila. Curr Biol 2021; 31:2065-2074.e5. [PMID: 33740428 DOI: 10.1016/j.cub.2021.02.044] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 12/22/2020] [Accepted: 02/17/2021] [Indexed: 01/05/2023]
Abstract
How social interactions influence cognition is a fundamental question, yet rarely addressed at the neurobiological level. It is well established that the presence of conspecifics affects learning and memory performance, but the neural basis of this process has only recently begun to be investigated. In the fruit fly Drosophila melanogaster, the presence of other flies improves retrieval of a long-lasting olfactory memory. Here, we demonstrate that this is a composite memory composed of two distinct elements. One is an individual memory that depends on outputs from the α'β' Kenyon cells (KCs) of the mushroom bodies (MBs), the memory center in the insect brain. The other is a group memory requiring output from the αβ KCs, a distinct sub-part of the MBs. We show that social facilitation of memory increases with group size and is triggered by CO2 released by group members. Among the different known neurons carrying CO2 information in the brain, we establish that the bilateral ventral projection neuron (biVPN), which projects onto the MBs, is necessary for social facilitation. Moreover, we demonstrate that CO2-evoked memory engages a serotoninergic pathway involving the dorsal-paired medial (DPM) neurons, revealing a new role for this pair of serotonergic neurons. Overall, we identified both the sensorial cue and the neural circuit (biVPN>αβ>DPM>αβ) governing social facilitation of memory in flies. This study provides demonstration that being in a group recruits the expression of a cryptic memory and that variations in CO2 concentration can affect cognitive processes in insects.
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Affiliation(s)
- Aurélie Muria
- Centre de Recherches sur la Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 118 route de Narbonne, Bat 4R4, 31062 Toulouse Cedex 9, France
| | - Pierre-Yves Musso
- Centre de Recherches sur la Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 118 route de Narbonne, Bat 4R4, 31062 Toulouse Cedex 9, France; Department of Zoology, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Matthias Durrieu
- Centre de Recherches sur la Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 118 route de Narbonne, Bat 4R4, 31062 Toulouse Cedex 9, France
| | - Felipe Ramon Portugal
- Laboratoire Évolution et Diversité Biologique (EDB UMR 5174), Université de Toulouse, CNRS, IRD, 118 route de Narbonne, Bat 4R1, 31062 Toulouse Cedex 9, France; Ecole Nationale Supérieure Formation de l'Enseignement Agricole, Castanet-Tolosan, France
| | - Brice Ronsin
- CBI, Université de Toulouse, CNRS, UPS, 118 route de Narbonne, Bat 4R4, 31062 Toulouse Cedex 9, France
| | - Michael D Gordon
- Department of Zoology, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Raphaël Jeanson
- Centre de Recherches sur la Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 118 route de Narbonne, Bat 4R4, 31062 Toulouse Cedex 9, France
| | - Guillaume Isabel
- Centre de Recherches sur la Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 118 route de Narbonne, Bat 4R4, 31062 Toulouse Cedex 9, France.
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32
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Mitchell J, Smith CS, Titlow J, Otto N, van Velde P, Booth M, Davis I, Waddell S. Selective dendritic localization of mRNA in Drosophila mushroom body output neurons. eLife 2021; 10:e62770. [PMID: 33724180 PMCID: PMC8004107 DOI: 10.7554/elife.62770] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Accepted: 03/15/2021] [Indexed: 11/24/2022] Open
Abstract
Memory-relevant neuronal plasticity is believed to require local translation of new proteins at synapses. Understanding this process requires the visualization of the relevant mRNAs within these neuronal compartments. Here, we used single-molecule fluorescence in situ hybridization to localize mRNAs at subcellular resolution in the adult Drosophila brain. mRNAs for subunits of nicotinic acetylcholine receptors and kinases could be detected within the dendrites of co-labeled mushroom body output neurons (MBONs) and their relative abundance showed cell specificity. Moreover, aversive olfactory learning produced a transient increase in the level of CaMKII mRNA within the dendritic compartments of the γ5β'2a MBONs. Localization of specific mRNAs in MBONs before and after learning represents a critical step towards deciphering the role of dendritic translation in the neuronal plasticity underlying behavioral change in Drosophila.
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Affiliation(s)
- Jessica Mitchell
- Centre for Neural Circuits and Behaviour, University of OxfordOxfordUnited Kingdom
| | - Carlas S Smith
- Centre for Neural Circuits and Behaviour, University of OxfordOxfordUnited Kingdom
- Delft Center for Systems and Control, Delft University of TechnologyDelftNetherlands
| | - Josh Titlow
- Department of Biochemistry, University of OxfordOxfordUnited Kingdom
| | - Nils Otto
- Centre for Neural Circuits and Behaviour, University of OxfordOxfordUnited Kingdom
| | - Pieter van Velde
- Delft Center for Systems and Control, Delft University of TechnologyDelftNetherlands
| | - Martin Booth
- Centre for Neural Circuits and Behaviour, University of OxfordOxfordUnited Kingdom
- Department of Engineering Science, University of OxfordOxfordUnited Kingdom
| | - Ilan Davis
- Department of Biochemistry, University of OxfordOxfordUnited Kingdom
| | - Scott Waddell
- Centre for Neural Circuits and Behaviour, University of OxfordOxfordUnited Kingdom
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33
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McCurdy LY, Sareen P, Davoudian PA, Nitabach MN. Dopaminergic mechanism underlying reward-encoding of punishment omission during reversal learning in Drosophila. Nat Commun 2021; 12:1115. [PMID: 33602917 PMCID: PMC7893153 DOI: 10.1038/s41467-021-21388-w] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 01/18/2021] [Indexed: 01/31/2023] Open
Abstract
Animals form and update learned associations between otherwise neutral sensory cues and aversive outcomes (i.e., punishment) to predict and avoid danger in changing environments. When a cue later occurs without punishment, this unexpected omission of aversive outcome is encoded as reward via activation of reward-encoding dopaminergic neurons. How such activation occurs remains unknown. Using real-time in vivo functional imaging, optogenetics, behavioral analysis and synaptic reconstruction from electron microscopy data, we identify the neural circuit mechanism through which Drosophila reward-encoding dopaminergic neurons are activated when an olfactory cue is unexpectedly no longer paired with electric shock punishment. Reduced activation of punishment-encoding dopaminergic neurons relieves depression of olfactory synaptic inputs to cholinergic neurons. Synaptic excitation by these cholinergic neurons of reward-encoding dopaminergic neurons increases their odor response, thus decreasing aversiveness of the odor. These studies reveal how an excitatory cholinergic relay from punishment- to reward-encoding dopaminergic neurons encodes the absence of punishment as reward, revealing a general circuit motif for updating aversive memories that could be present in mammals.
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Affiliation(s)
- Li Yan McCurdy
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT, USA
- Department of Cellular & Molecular Physiology, Yale University, New Haven, CT, USA
| | - Preeti Sareen
- Department of Cellular & Molecular Physiology, Yale University, New Haven, CT, USA
| | - Pasha A Davoudian
- Department of Neuroscience, Yale University, New Haven, CT, USA
- MD/PhD Program, Yale School of Medicine, Yale University, New Haven, CT, USA
| | - Michael N Nitabach
- Department of Cellular & Molecular Physiology, Yale University, New Haven, CT, USA.
- Department of Neuroscience, Yale University, New Haven, CT, USA.
- Department of Genetics, Yale University, New Haven, CT, USA.
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34
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Ichinose T, Kanno M, Wu H, Yamagata N, Sun H, Abe A, Tanimoto H. Mushroom body output differentiates memory processes and distinct memory-guided behaviors. Curr Biol 2021; 31:1294-1302.e4. [PMID: 33476556 DOI: 10.1016/j.cub.2020.12.032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 10/29/2020] [Accepted: 12/21/2020] [Indexed: 12/14/2022]
Abstract
The mushroom body (MB) of Drosophila melanogaster has multiple functions in controlling memory and behavior.1-9 However, circuit mechanisms that generate this functional diversity are largely unclear. Here, we systematically probed the behavioral contribution of each type of MB output neuron (MBON) by blocking during acquisition, retention, or retrieval of reward or punishment memories. We evaluated the contribution using two conditioned responses: memory-guided odor choice and odor source attraction. Quantitative analysis revealed that these conditioned odor responses are controlled by different sets of MBONs. We found that the valence of memory, rather than the transition of memory steps, has a larger impact on the patterns of required MBONs. Moreover, we found that the glutamatergic MBONs forming recurrent circuits commonly contribute to appetitive memory acquisition, suggesting a pivotal role of this circuit motif for reward processing. Our results provide principles how the MB output circuit processes associative memories of different valence and controls distinct memory-guided behaviors.
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Affiliation(s)
- Toshiharu Ichinose
- Graduate School of Life Sciences, Tohoku University, Sendai 980-8577, Japan; Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai 980-8578, Japan; Center for Transdisciplinary Research, Niigata University, Niigata 950-2181, Japan; Department of Neuropharmacology, Nagoya City University, Nagoya 467-8603, Japan.
| | - Mai Kanno
- Graduate School of Life Sciences, Tohoku University, Sendai 980-8577, Japan
| | - Hongyang Wu
- Graduate School of Life Sciences, Tohoku University, Sendai 980-8577, Japan
| | - Nobuhiro Yamagata
- Graduate School of Life Sciences, Tohoku University, Sendai 980-8577, Japan
| | - Huan Sun
- Graduate School of Life Sciences, Tohoku University, Sendai 980-8577, Japan
| | - Ayako Abe
- Graduate School of Life Sciences, Tohoku University, Sendai 980-8577, Japan
| | - Hiromu Tanimoto
- Graduate School of Life Sciences, Tohoku University, Sendai 980-8577, Japan.
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35
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Felsenberg J. Changing memories on the fly: the neural circuits of memory re-evaluation in Drosophila melanogaster. Curr Opin Neurobiol 2020; 67:190-198. [PMID: 33373859 DOI: 10.1016/j.conb.2020.12.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 12/03/2020] [Accepted: 12/07/2020] [Indexed: 11/30/2022]
Abstract
Associative learning leads to modifications in neural networks to assign valence to sensory cues. These changes not only allow the expression of learned behavior but also modulate subsequent learning events. In the brain of the adult fruit fly, Drosophila melanogaster, olfactory memories are established as dopamine-driven plasticity in the output of a highly recurrent network, the mushroom body. Recent findings have highlighted how these changes in the network can steer the strengthening, weakening and formation of parallel memories when flies are exposed to subsequent training trials, conflicting situations or the reversal of contingencies. Together, these processes provide an initial understanding of how learned information can be used to guide the re-evaluation of memories.
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36
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Li F, Lindsey JW, Marin EC, Otto N, Dreher M, Dempsey G, Stark I, Bates AS, Pleijzier MW, Schlegel P, Nern A, Takemura SY, Eckstein N, Yang T, Francis A, Braun A, Parekh R, Costa M, Scheffer LK, Aso Y, Jefferis GSXE, Abbott LF, Litwin-Kumar A, Waddell S, Rubin GM. The connectome of the adult Drosophila mushroom body provides insights into function. eLife 2020; 9:e62576. [PMID: 33315010 PMCID: PMC7909955 DOI: 10.7554/elife.62576] [Citation(s) in RCA: 157] [Impact Index Per Article: 39.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 12/11/2020] [Indexed: 12/12/2022] Open
Abstract
Making inferences about the computations performed by neuronal circuits from synapse-level connectivity maps is an emerging opportunity in neuroscience. The mushroom body (MB) is well positioned for developing and testing such an approach due to its conserved neuronal architecture, recently completed dense connectome, and extensive prior experimental studies of its roles in learning, memory, and activity regulation. Here, we identify new components of the MB circuit in Drosophila, including extensive visual input and MB output neurons (MBONs) with direct connections to descending neurons. We find unexpected structure in sensory inputs, in the transfer of information about different sensory modalities to MBONs, and in the modulation of that transfer by dopaminergic neurons (DANs). We provide insights into the circuitry used to integrate MB outputs, connectivity between the MB and the central complex and inputs to DANs, including feedback from MBONs. Our results provide a foundation for further theoretical and experimental work.
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Affiliation(s)
- Feng Li
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Jack W Lindsey
- Department of Neuroscience, Columbia University, Zuckerman InstituteNew YorkUnited States
| | - Elizabeth C Marin
- Drosophila Connectomics Group, Department of Zoology, University of CambridgeCambridgeUnited Kingdom
| | - Nils Otto
- Drosophila Connectomics Group, Department of Zoology, University of CambridgeCambridgeUnited Kingdom
- Centre for Neural Circuits & Behaviour, University of OxfordOxfordUnited Kingdom
| | - Marisa Dreher
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Georgia Dempsey
- Drosophila Connectomics Group, Department of Zoology, University of CambridgeCambridgeUnited Kingdom
| | - Ildiko Stark
- Drosophila Connectomics Group, Department of Zoology, University of CambridgeCambridgeUnited Kingdom
| | - Alexander S Bates
- Neurobiology Division, MRC Laboratory of Molecular BiologyCambridgeUnited Kingdom
| | | | - Philipp Schlegel
- Drosophila Connectomics Group, Department of Zoology, University of CambridgeCambridgeUnited Kingdom
- Neurobiology Division, MRC Laboratory of Molecular BiologyCambridgeUnited Kingdom
| | - Aljoscha Nern
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Shin-ya Takemura
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Nils Eckstein
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Tansy Yang
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Audrey Francis
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Amalia Braun
- Drosophila Connectomics Group, Department of Zoology, University of CambridgeCambridgeUnited Kingdom
| | - Ruchi Parekh
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Marta Costa
- Drosophila Connectomics Group, Department of Zoology, University of CambridgeCambridgeUnited Kingdom
| | - Louis K Scheffer
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Yoshinori Aso
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Gregory SXE Jefferis
- Drosophila Connectomics Group, Department of Zoology, University of CambridgeCambridgeUnited Kingdom
- Neurobiology Division, MRC Laboratory of Molecular BiologyCambridgeUnited Kingdom
| | - Larry F Abbott
- Department of Neuroscience, Columbia University, Zuckerman InstituteNew YorkUnited States
| | - Ashok Litwin-Kumar
- Department of Neuroscience, Columbia University, Zuckerman InstituteNew YorkUnited States
| | - Scott Waddell
- Centre for Neural Circuits & Behaviour, University of OxfordOxfordUnited Kingdom
| | - Gerald M Rubin
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
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37
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Insulin signaling represents a gating mechanism between different memory phases in Drosophila larvae. PLoS Genet 2020; 16:e1009064. [PMID: 33104728 PMCID: PMC7644093 DOI: 10.1371/journal.pgen.1009064] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 11/05/2020] [Accepted: 08/19/2020] [Indexed: 12/18/2022] Open
Abstract
The ability to learn new skills and to store them as memory entities is one of the most impressive features of higher evolved organisms. However, not all memories are created equal; some are short-lived forms, and some are longer lasting. Formation of the latter is energetically costly and by the reason of restricted availability of food or fluctuations in energy expanses, efficient metabolic homeostasis modulating different needs like survival, growth, reproduction, or investment in longer lasting memories is crucial. Whilst equipped with cellular and molecular pre-requisites for formation of a protein synthesis dependent long-term memory (LTM), its existence in the larval stage of Drosophila remains elusive. Considering it from the viewpoint that larval brain structures are completely rebuilt during metamorphosis, and that this process depends completely on accumulated energy stores formed during the larval stage, investing in LTM represents an unnecessary expenditure. However, as an alternative, Drosophila larvae are equipped with the capacity to form a protein synthesis independent so-called larval anaesthesia resistant memory (lARM), which is consolidated in terms of being insensitive to cold-shock treatments. Motivated by the fact that LTM formation causes an increase in energy uptake in Drosophila adults, we tested the idea of whether an energy surplus can induce the formation of LTM in the larval stage. Suprisingly, increasing the metabolic state by feeding Drosophila larvae the disaccharide sucrose directly before aversive olfactory conditioning led to the formation of a protein synthesis dependent longer lasting memory. Moreover, formation of this memory component is accompanied by the suppression of lARM. We ascertained that insulin receptors (InRs) expressed in the mushroom body Kenyon cells suppresses the formation of lARM and induces the formation of a protein synthesis dependent longer lasting memory in Drosophila larvae. Given the numerical simplicity of the larval nervous system this work offers a unique prospect to study the impact of insulin signaling on the formation of protein synthesis dependent memories on a molecular level.
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Cervantes-Sandoval I, Davis RL, Berry JA. Rac1 Impairs Forgetting-Induced Cellular Plasticity in Mushroom Body Output Neurons. Front Cell Neurosci 2020; 14:258. [PMID: 33061890 PMCID: PMC7477079 DOI: 10.3389/fncel.2020.00258] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 07/24/2020] [Indexed: 12/02/2022] Open
Abstract
Active memory forgetting is a well-regulated biological process thought to be adaptive and to allow proper cognitive functions. Recent efforts have elucidated several molecular players involved in the regulation of olfactory forgetting in Drosophila, including the small G protein Rac1, the dopamine receptor DAMB, and the scaffold protein Scribble. Similarly, we recently reported that dopaminergic neurons mediate both learning- and forgetting-induced plasticity in the mushroom body output neuron MBON-γ2α′1. Two open questions remain: how does forgetting affect plasticity in other, highly plastic, mushroom body compartments and how do genes that regulate forgetting affect this cellular plasticity? Here, we show that forgetting reverses short-term synaptic depression induced by aversive conditioning in the highly plastic mushroom body output neuron MBON-γ1pedc>α/β. In addition, our results indicate that genetic tampering with normal forgetting by inhibition of small G protein Rac1 impairs restoration of depressed odor responses to learned odor by intrinsic forgetting through time passing and forgetting induced acutely by shock stimulation after conditioning or reversal learning. These data further indicate that some forms of forgetting truly erase physiological changes generated by memory encoding.
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Affiliation(s)
- Isaac Cervantes-Sandoval
- Department of Biology, Georgetown University, Washington, DC, United States.,Interdisciplinary Program in Neuroscience, Georgetown University, Washington, DC, United States
| | - Ronald L Davis
- Department of Neuroscience, The Scripps Research Institute Florida, Jupiter, FL, United States
| | - Jacob A Berry
- Department of Neuroscience, The Scripps Research Institute Florida, Jupiter, FL, United States
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39
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Schleyer M, Weiglein A, Thoener J, Strauch M, Hartenstein V, Kantar Weigelt M, Schuller S, Saumweber T, Eichler K, Rohwedder A, Merhof D, Zlatic M, Thum AS, Gerber B. Identification of Dopaminergic Neurons That Can Both Establish Associative Memory and Acutely Terminate Its Behavioral Expression. J Neurosci 2020; 40:5990-6006. [PMID: 32586949 PMCID: PMC7392503 DOI: 10.1523/jneurosci.0290-20.2020] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 04/14/2020] [Accepted: 05/19/2020] [Indexed: 02/01/2023] Open
Abstract
An adaptive transition from exploring the environment in search of vital resources to exploiting these resources once the search was successful is important to all animals. Here we study the neuronal circuitry that allows larval Drosophila melanogaster of either sex to negotiate this exploration-exploitation transition. We do so by combining Pavlovian conditioning with high-resolution behavioral tracking, optogenetic manipulation of individually identified neurons, and EM data-based analyses of synaptic organization. We find that optogenetic activation of the dopaminergic neuron DAN-i1 can both establish memory during training and acutely terminate learned search behavior in a subsequent recall test. Its activation leaves innate behavior unaffected, however. Specifically, DAN-i1 activation can establish associative memories of opposite valence after paired and unpaired training with odor, and its activation during the recall test can terminate the search behavior resulting from either of these memories. Our results further suggest that in its behavioral significance DAN-i1 activation resembles, but does not equal, sugar reward. Dendrogram analyses of all the synaptic connections between DAN-i1 and its two main targets, the Kenyon cells and the mushroom body output neuron MBON-i1, further suggest that the DAN-i1 signals during training and during the recall test could be delivered to the Kenyon cells and to MBON-i1, respectively, within previously unrecognized, locally confined branching structures. This would provide an elegant circuit motif to terminate search on its successful completion.SIGNIFICANCE STATEMENT In the struggle for survival, animals have to explore their environment in search of food. Once food is found, however, it is adaptive to prioritize exploiting it over continuing a search that would now be as pointless as searching for the glasses you are wearing. This exploration-exploitation trade-off is important for animals and humans, as well as for technical search devices. We investigate which of the only 10,000 neurons of a fruit fly larva can tip the balance in this trade-off, and identify a single dopamine neuron called DAN-i1 that can do so. Given the similarities in dopamine neuron function across the animal kingdom, this may reflect a general principle of how search is terminated once it is successful.
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Affiliation(s)
- Michael Schleyer
- Leibniz Institute for Neurobiology, Department Genetics of Learning and Memory, 39118 Magdeburg, Germany
| | - Aliće Weiglein
- Leibniz Institute for Neurobiology, Department Genetics of Learning and Memory, 39118 Magdeburg, Germany
| | - Juliane Thoener
- Leibniz Institute for Neurobiology, Department Genetics of Learning and Memory, 39118 Magdeburg, Germany
| | - Martin Strauch
- Institute of Imaging & Computer Vision, RWTH Aachen University, 52056 Aachen, Germany
| | - Volker Hartenstein
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, California 90095-1606
| | - Melisa Kantar Weigelt
- Leibniz Institute for Neurobiology, Department Genetics of Learning and Memory, 39118 Magdeburg, Germany
| | - Sarah Schuller
- Leibniz Institute for Neurobiology, Department Genetics of Learning and Memory, 39118 Magdeburg, Germany
| | - Timo Saumweber
- Leibniz Institute for Neurobiology, Department Genetics of Learning and Memory, 39118 Magdeburg, Germany
| | - Katharina Eichler
- University of Konstanz, Institute for Biology, 78464 Konstanz, Germany
- HHMI Janelia Research Campus, Ashburn, Virginia 20147
- Institute of Neurobiology, University of Puerto Rico Medical Science Campus, Old San Juan, Puerto Rico 00901
| | - Astrid Rohwedder
- University of Konstanz, Institute for Biology, 78464 Konstanz, Germany
- Department of Zoology, University of Cambridge, Cambridge, CB2 3EJ, United Kingdom
| | - Dorit Merhof
- Institute of Imaging & Computer Vision, RWTH Aachen University, 52056 Aachen, Germany
| | - Marta Zlatic
- HHMI Janelia Research Campus, Ashburn, Virginia 20147
- Department of Zoology, University of Cambridge, Cambridge, CB2 3EJ, United Kingdom
| | - Andreas S Thum
- University of Konstanz, Institute for Biology, 78464 Konstanz, Germany
- University Leipzig, Institute for Biology, 04103 Leipzig, Germany
| | - Bertram Gerber
- Leibniz Institute for Neurobiology, Department Genetics of Learning and Memory, 39118 Magdeburg, Germany
- Centre for Behavioural Brain Sciences, 39108 Magdeburg, Germany
- Institute for Biology, Otto von Guericke University Magdeburg, 39106 Magdeburg, Germany
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40
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Boto T, Stahl A, Zhang X, Louis T, Tomchik SM. Independent Contributions of Discrete Dopaminergic Circuits to Cellular Plasticity, Memory Strength, and Valence in Drosophila. Cell Rep 2020; 27:2014-2021.e2. [PMID: 31091441 PMCID: PMC6585410 DOI: 10.1016/j.celrep.2019.04.069] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 02/18/2019] [Accepted: 04/11/2019] [Indexed: 01/13/2023] Open
Abstract
Dopaminergic neurons play a key role in encoding associative memories, but little is known about how these circuits modulate memory strength. Here we report that different sets of dopaminergic neurons projecting to the Drosophila mushroom body (MB) differentially regulate valence and memory strength. PPL2 neurons increase odor-evoked calcium re- sponses to a paired odor in the MB and enhance behavioral memory strength when activated during olfactory classical conditioning. When paired with odor alone, they increase MB responses to the paired odor but do not drive behavioral approach or avoidance, suggesting that they increase the salience of the odor without encoding strong valence. This contrasts with the role of dopaminergic PPL1 neurons, which drive behavioral reinforcement but do not alter odor-evoked calcium responses in the MB when stimulated. These data suggest that different sets of dopaminergic neurons modulate olfactory valence and memory strength via independent actions on a memory-encoding brain region. Boto et al. investigated the roles of two sets of dopaminergic neurons that converge on a memory-encoding brain region in flies. While one set, PPL1, drives aversive reinforcement (valence), PPL2 neurons enhance memory strength via modulation of Ca2+ response plasticity in memory-encoding mushroom body neurons.
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Affiliation(s)
- Tamara Boto
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Aaron Stahl
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Xiaofan Zhang
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Thierry Louis
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Seth M Tomchik
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA.
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41
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Jacob PF, Waddell S. Spaced Training Forms Complementary Long-Term Memories of Opposite Valence in Drosophila. Neuron 2020; 106:977-991.e4. [PMID: 32289250 PMCID: PMC7302427 DOI: 10.1016/j.neuron.2020.03.013] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 01/25/2020] [Accepted: 03/16/2020] [Indexed: 12/30/2022]
Abstract
Forming long-term memory (LTM) often requires repetitive experience spread over time. Studies in Drosophila suggest aversive olfactory LTM is optimal after spaced training, multiple trials of differential odor conditioning with rest intervals. Memory after spaced training is frequently compared to that after the same number of trials without intervals. Here we show that, after spaced training, flies acquire additional information and form an aversive memory for the shock-paired odor and a slowly emerging and more persistent "safety-memory" for the explicitly unpaired odor. Safety-memory acquisition requires repetition, order, and spacing of the training trials and relies on triggering specific rewarding dopaminergic neurons. Co-existence of aversive and safety memories is evident as depression of odor-specific responses at different combinations of junctions in the mushroom body output network; combining two outputs appears to signal relative safety. Having complementary aversive and safety memories augments LTM performance after spaced training by making the odor preference more certain.
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Affiliation(s)
- Pedro F Jacob
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford OX1 3TA, UK
| | - Scott Waddell
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford OX1 3TA, UK.
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42
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Siju KP, Štih V, Aimon S, Gjorgjieva J, Portugues R, Grunwald Kadow IC. Valence and State-Dependent Population Coding in Dopaminergic Neurons in the Fly Mushroom Body. Curr Biol 2020; 30:2104-2115.e4. [PMID: 32386530 DOI: 10.1016/j.cub.2020.04.037] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 03/13/2020] [Accepted: 04/16/2020] [Indexed: 11/26/2022]
Abstract
Neuromodulation permits flexibility of synapses, neural circuits, and ultimately behavior. One neuromodulator, dopamine, has been studied extensively in its role as a reward signal during learning and memory across animal species. Newer evidence suggests that dopaminergic neurons (DANs) can modulate sensory perception acutely, thereby allowing an animal to adapt its behavior and decision making to its internal and behavioral state. In addition, some data indicate that DANs are not homogeneous but rather convey different types of information as a heterogeneous population. We have investigated DAN population activity and how it could encode relevant information about sensory stimuli and state by taking advantage of the confined anatomy of DANs innervating the mushroom body (MB) of the fly Drosophila melanogaster. Using in vivo calcium imaging and a custom 3D image registration method, we found that the activity of the population of MB DANs encodes innate valence information of an odor or taste as well as the physiological state of the animal. Furthermore, DAN population activity is strongly correlated with movement, consistent with a role of dopamine in conveying behavioral state to the MB. Altogether, our data and analysis suggest that DAN population activities encode innate odor and taste valence, movement, and physiological state in a MB-compartment-specific manner. We propose that dopamine shapes innate perception through combinatorial population coding of sensory valence, physiological, and behavioral context.
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Affiliation(s)
- K P Siju
- TUM School of Life Sciences, Technical University of Munich, 85354 Freising, Germany
| | - Vilim Štih
- Sensorimotor Control Group, Max Planck Institute of Neurobiology, 82152 Martinsried, Germany
| | - Sophie Aimon
- TUM School of Life Sciences, Technical University of Munich, 85354 Freising, Germany
| | - Julijana Gjorgjieva
- TUM School of Life Sciences, Technical University of Munich, 85354 Freising, Germany; Computation in Neural Circuits Group, Max Planck Institute for Brain Research, 60438 Frankfurt am Main, Germany
| | - Ruben Portugues
- Sensorimotor Control Group, Max Planck Institute of Neurobiology, 82152 Martinsried, Germany; Institute of Neuroscience, Technical University of Munich, 80802 Munich, Germany; Munich Cluster for Systems Neurology (SyNergy), 80802 Munich, Germany
| | - Ilona C Grunwald Kadow
- TUM School of Life Sciences, Technical University of Munich, 85354 Freising, Germany; ZIEL-Institute of Food and Health, Technical University of Munich, 85354 Freising, Germany.
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43
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Rapid Aversive and Memory Trace Learning during Route Navigation in Desert Ants. Curr Biol 2020; 30:1927-1933.e2. [DOI: 10.1016/j.cub.2020.02.082] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Revised: 02/03/2020] [Accepted: 02/26/2020] [Indexed: 11/19/2022]
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44
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Delestro F, Scheunemann L, Pedrazzani M, Tchenio P, Preat T, Genovesio A. In vivo large-scale analysis of Drosophila neuronal calcium traces by automated tracking of single somata. Sci Rep 2020; 10:7153. [PMID: 32346011 PMCID: PMC7188892 DOI: 10.1038/s41598-020-64060-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 04/07/2020] [Indexed: 01/30/2023] Open
Abstract
How does the concerted activity of neuronal populations shape behavior? Impediments to address this question are primarily due to critical experimental barriers. An integrated perspective on large scale neural information processing requires an in vivo approach that can combine the advantages of exhaustively observing all neurons dedicated to a given type of stimulus, and simultaneously achieve a resolution that is precise enough to capture individual neuron activity. Current experimental data from in vivo observations are either restricted to a small fraction of the total number of neurons, or are based on larger brain volumes but at a low spatial and temporal resolution. Consequently, fundamental questions as to how sensory information is represented on a population scale remain unanswered. In Drosophila melanogaster, the mushroom body (MB) represents an excellent model to analyze sensory coding and memory plasticity. In this work, we present an experimental setup coupled with a dedicated computational method that provides in vivo measurements of the activity of hundreds of densely packed somata uniformly spread in the MB. We exploit spinning-disk confocal 3D imaging over time of the whole MB cell body layer in vivo while it is exposed to olfactory stimulation. Importantly, to derive individual signal from densely packed somata, we have developed a fully automated image analysis procedure that takes advantage of the specificities of our data. After anisotropy correction, our approach operates a dedicated spot detection and registration over the entire time sequence to transform trajectories to identifiable clusters. This enabled us to discard spurious detections and reconstruct missing ones in a robust way. We demonstrate that this approach outperformed existing methods in this specific context and made possible high-throughput analysis of approximately 500 single somata uniformly spread over the MB in various conditions. Applying this approach, we find that learned experiences change the population code of odor representations in the MB. After long-term memory (LTM) formation, we quantified an increase in responsive somata count and a stable single neuron signal. We predict that this method, which should further enable studying the population pattern of neuronal activity, has the potential to uncover fine details of sensory processing and memory plasticity.
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Affiliation(s)
- Felipe Delestro
- Computational Bioimaging and Bioinformatics, IBENS, ENS, INSERM, CNRS, PSL, 46 rue d'Ulm, 75005, Paris, France
| | - Lisa Scheunemann
- Genes and Dynamics of Memory Systems, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL, 10 Rue Vauquelin, 75005, Paris, France
| | - Mélanie Pedrazzani
- Genes and Dynamics of Memory Systems, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL, 10 Rue Vauquelin, 75005, Paris, France
| | - Paul Tchenio
- Genes and Dynamics of Memory Systems, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL, 10 Rue Vauquelin, 75005, Paris, France
| | - Thomas Preat
- Genes and Dynamics of Memory Systems, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL, 10 Rue Vauquelin, 75005, Paris, France.
| | - Auguste Genovesio
- Computational Bioimaging and Bioinformatics, IBENS, ENS, INSERM, CNRS, PSL, 46 rue d'Ulm, 75005, Paris, France.
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45
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Drosophila Middle-Term Memory: Amnesiac is Required for PKA Activation in the Mushroom Bodies, a Function Modulated by Neprilysin 1. J Neurosci 2020; 40:4219-4229. [PMID: 32303647 DOI: 10.1523/jneurosci.2311-19.2020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 03/30/2020] [Accepted: 04/05/2020] [Indexed: 11/21/2022] Open
Abstract
In Drosophila, the mushroom bodies (MB) constitute the central brain structure for olfactory associative memory. As in mammals, the cAMP/PKA pathway plays a key role in memory formation. In the MB, Rutabaga (Rut) adenylate cyclase acts as a coincidence detector during associative conditioning to integrate calcium influx resulting from acetylcholine stimulation and G-protein activation resulting from dopaminergic stimulation. Amnesiac encodes a secreted neuropeptide required in the MB for two phases of aversive olfactory memory. Previous sequence analysis has revealed strong homology with the mammalian pituitary adenylate cyclase-activating peptide (PACAP). Here, we examined whether amnesiac is involved in cAMP/PKA dynamics in response to dopamine and acetylcholine co-stimulation in living flies. Experiments were conducted with both sexes, or with either sex. Our data show that amnesiac is necessary for the PKA activation process that results from coincidence detection in the MB. Since PACAP peptide is cleaved by the human membrane neprilysin hNEP, we searched for an interaction between Amnesiac and Neprilysin 1 (Nep1), a fly neprilysin involved in memory. We show that when Nep1 expression is acutely knocked down in adult MB, memory deficits displayed by amn hypomorphic mutants are rescued. Consistently, Nep1 inhibition also restores normal PKA activation in amn mutant flies. Taken together, the results suggest that Nep1 targets Amnesiac degradation to terminate its signaling function. Our work thus highlights a key role for Amnesiac in establishing within the MB the PKA dynamics that sustain middle-term memory (MTM) formation, a function modulated by Nep1.SIGNIFICANCE STATEMENT The Drosophila amnesiac gene encodes a secreted neuropeptide whose expression is required for specific memory phases in the mushroom bodies (MB), the olfactory memory center. Here, we show that Amnesiac is required for PKA activation resulting from coincidence detection, a mechanism by which the MB integrate two spatially distinct stimuli to encode associative memory. Furthermore, our results uncover a functional relationship between Amnesiac and Neprilysin 1 (Nep1), a membrane peptidase involved in memory and expressed in the MB. These results suggest that Nep1 modulates Amnesiac levels. We propose that on conditioning, Amnesiac release from the MB allows, via an autocrine process, the sustaining of PKA activation-mediating memory, which subsequently is inactivated by Nep1 degradation.
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46
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Modi MN, Shuai Y, Turner GC. The Drosophila Mushroom Body: From Architecture to Algorithm in a Learning Circuit. Annu Rev Neurosci 2020; 43:465-484. [PMID: 32283995 DOI: 10.1146/annurev-neuro-080317-0621333] [Citation(s) in RCA: 86] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The Drosophila brain contains a relatively simple circuit for forming Pavlovian associations, yet it achieves many operations common across memory systems. Recent advances have established a clear framework for Drosophila learning and revealed the following key operations: a) pattern separation, whereby dense combinatorial representations of odors are preprocessed to generate highly specific, nonoverlapping odor patterns used for learning; b) convergence, in which sensory information is funneled to a small set of output neurons that guide behavioral actions; c) plasticity, where changing the mapping of sensory input to behavioral output requires a strong reinforcement signal, which is also modulated by internal state and environmental context; and d) modularization, in which a memory consists of multiple parallel traces, which are distinct in stability and flexibility and exist in anatomically well-defined modules within the network. Cross-module interactions allow for higher-order effects where past experience influences future learning. Many of these operations have parallels with processes of memory formation and action selection in more complex brains.
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Affiliation(s)
- Mehrab N Modi
- Janelia Research Campus, Ashburn, Virginia 20147, USA;
| | - Yichun Shuai
- Janelia Research Campus, Ashburn, Virginia 20147, USA;
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47
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Bilz F, Geurten BRH, Hancock CE, Widmann A, Fiala A. Visualization of a Distributed Synaptic Memory Code in the Drosophila Brain. Neuron 2020; 106:963-976.e4. [PMID: 32268119 DOI: 10.1016/j.neuron.2020.03.010] [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: 04/11/2019] [Revised: 11/19/2019] [Accepted: 03/13/2020] [Indexed: 10/24/2022]
Abstract
During associative conditioning, animals learn which sensory cues are predictive for positive or negative conditions. Because sensory cues are encoded by distributed neurons, one has to monitor plasticity across many synapses to capture how learned information is encoded. We analyzed synaptic boutons of Kenyon cells of the Drosophila mushroom body γ lobe, a brain structure that mediates olfactory learning. A fluorescent Ca2+ sensor was expressed in single Kenyon cells so that axonal boutons could be assigned to distinct cells and Ca2+ could be measured across many animals. Learning induced directed synaptic plasticity in specific compartments along the axons. Moreover, we show that odor-evoked Ca2+ dynamics across boutons decorrelate as a result of associative learning. Information theory indicates that learning renders the stimulus representation more distinct compared with naive stimuli. These data reveal that synaptic boutons rather than cells act as individually modifiable units, and coherence among them is a memory-encoding parameter.
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Affiliation(s)
- Florian Bilz
- Department of Molecular Neurobiology of Behavior, Johann-Friedrich-Blumenbach-Institute for Zoology and Anthropology, University of Göttingen, Julia-Lermontowa-Weg 3, 37077 Göttingen, Germany
| | - Bart R H Geurten
- Department of Cellular Neurobiology, Johann-Friedrich-Blumenbach-Institute for Zoology and Anthropology, University of Göttingen, Julia-Lermontowa-Weg 3, 37077 Göttingen, Germany
| | - Clare E Hancock
- Department of Molecular Neurobiology of Behavior, Johann-Friedrich-Blumenbach-Institute for Zoology and Anthropology, University of Göttingen, Julia-Lermontowa-Weg 3, 37077 Göttingen, Germany
| | - Annekathrin Widmann
- Department of Molecular Neurobiology of Behavior, Johann-Friedrich-Blumenbach-Institute for Zoology and Anthropology, University of Göttingen, Julia-Lermontowa-Weg 3, 37077 Göttingen, Germany
| | - André Fiala
- Department of Molecular Neurobiology of Behavior, Johann-Friedrich-Blumenbach-Institute for Zoology and Anthropology, University of Göttingen, Julia-Lermontowa-Weg 3, 37077 Göttingen, Germany.
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48
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Abstract
Perseverance in foraging is a high-risk/high-gain strategy. In this issue of Neuron, Sayin et al. (2019) decipher the neuronal circuit that arbitrates this choice in Drosophila. The fly's remarkable tenacity illuminates the interaction between working memory and decision making.
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49
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Boto T, Stahl A, Tomchik SM. Cellular and circuit mechanisms of olfactory associative learning in Drosophila. J Neurogenet 2020; 34:36-46. [PMID: 32043414 DOI: 10.1080/01677063.2020.1715971] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Recent years have witnessed significant progress in understanding how memories are encoded, from the molecular to the cellular and the circuit/systems levels. With a good compromise between brain complexity and behavioral sophistication, the fruit fly Drosophila melanogaster is one of the preeminent animal models of learning and memory. Here we review how memories are encoded in Drosophila, with a focus on short-term memory and an eye toward future directions. Forward genetic screens have revealed a large number of genes and transcripts necessary for learning and memory, some acting cell-autonomously. Further, the relative numerical simplicity of the fly brain has enabled the reverse engineering of learning circuits with remarkable precision, in some cases ascribing behavioral phenotypes to single neurons. Functional imaging and physiological studies have localized and parsed the plasticity that occurs during learning at some of the major loci. Connectomics projects are significantly expanding anatomical knowledge of the nervous system, filling out the roadmap for ongoing functional/physiological and behavioral studies, which are being accelerated by simultaneous tool development. These developments have provided unprecedented insight into the fundamental neural principles of learning, and lay the groundwork for deep understanding in the near future.
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Affiliation(s)
- Tamara Boto
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL, USA
| | - Aaron Stahl
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL, USA
| | - Seth M Tomchik
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL, USA
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50
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Woitkuhn J, Ender A, Beuschel CB, Maglione M, Matkovic-Rachid T, Huang S, Lehmann M, Geiger JRP, Sigrist SJ. The Unc13A isoform is important for phasic release and olfactory memory formation at mushroom body synapses. J Neurogenet 2020; 34:106-114. [PMID: 31980003 DOI: 10.1080/01677063.2019.1710146] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The cellular analysis of mushroom body (MB)-dependent memory forming processes is far advanced, whereas, the molecular and physiological understanding of their synaptic basis lags behind. Recent analysis of the Drosophila olfactory system showed that Unc13A, a member of the M(Unc13) release factor family, promotes a phasic, high release probability component, while Unc13B supports a slower tonic release component, reflecting their different nanoscopic positioning within individual active zones. We here use STED super-resolution microscopy of MB lobe synapses to show that Unc13A clusters closer to the active zone centre than Unc13B. Unc13A specifically supported phasic transmission and short-term plasticity of Kenyon cell:output neuron synapses, measured by combining electrophysiological recordings of output neurons with optogenetic stimulation. Knockdown of unc13A within Kenyon cells provoked drastic deficits of olfactory aversive short-term and anaesthesia-sensitive middle-term memory. Knockdown of unc13B provoked milder memory deficits. Thus, a low frequency domain transmission component is probably crucial for the proper representation of memory-associated activity patterns, consistent with sparse Kenyon cell activation during memory acquisition and retrieval. Notably, Unc13A/B ratios appeared highly diversified across MB lobes, leaving room for an interplay of activity components in memory encoding and retrieval.
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Affiliation(s)
- Jennifer Woitkuhn
- Institute for Biology/Genetics, Freie Universitaet Berlin, Berlin, Germany
| | - Anatoli Ender
- German Center for Neurodegenerative Disorders, Charité Universitätsmedizin Berlin, Berlin, Germany
| | | | - Marta Maglione
- Institute for Biology/Genetics, Freie Universitaet Berlin, Berlin, Germany.,NeuroCure Cluster of Excellence, Charité Universitätsmedizin, Berlin, Germany.,Cellular Imaging, Light Microscopy, Leibniz-Forschungsinstitut fur Molekulare Pharmakologie (FMP), Berlin, Germany
| | | | - Sheng Huang
- Institute for Biology/Genetics, Freie Universitaet Berlin, Berlin, Germany
| | - Martin Lehmann
- Cellular Imaging, Light Microscopy, Leibniz-Forschungsinstitut fur Molekulare Pharmakologie (FMP), Berlin, Germany
| | - Joerg R P Geiger
- NeuroCure Cluster of Excellence, Charité Universitätsmedizin, Berlin, Germany.,Institut fur Neurophysiologie, Charité Universitätsmedizin, Berlin, Germany
| | - Stephan J Sigrist
- Institute for Biology/Genetics, Freie Universitaet Berlin, Berlin, Germany.,German Center for Neurodegenerative Disorders, Charité Universitätsmedizin Berlin, Berlin, Germany.,NeuroCure Cluster of Excellence, Charité Universitätsmedizin, Berlin, Germany
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