1
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Berry JA, Guhle DC, Davis RL. Active forgetting and neuropsychiatric diseases. Mol Psychiatry 2024; 29:2810-2820. [PMID: 38532011 PMCID: PMC11420092 DOI: 10.1038/s41380-024-02521-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 03/04/2024] [Accepted: 03/06/2024] [Indexed: 03/28/2024]
Abstract
Recent and pioneering animal research has revealed the brain utilizes a variety of molecular, cellular, and network-level mechanisms used to forget memories in a process referred to as "active forgetting". Active forgetting increases behavioral flexibility and removes irrelevant information. Individuals with impaired active forgetting mechanisms can experience intrusive memories, distressing thoughts, and unwanted impulses that occur in neuropsychiatric diseases. The current evidence indicates that active forgetting mechanisms degrade, or mask, molecular and cellular memory traces created in synaptic connections of "engram cells" that are specific for a given memory. Combined molecular genetic/behavioral studies using Drosophila have uncovered a complex system of cellular active-forgetting pathways within engram cells that is regulated by dopamine neurons and involves dopamine-nitric oxide co-transmission and reception, endoplasmic reticulum Ca2+ signaling, and cytoskeletal remodeling machinery regulated by small GTPases. Some of these molecular cellular mechanisms have already been found to be conserved in mammals. Interestingly, some pathways independently regulate forgetting of distinct memory types and temporal phases, suggesting a multi-layering organization of forgetting systems. In mammals, active forgetting also involves modulation of memory trace synaptic strength by altering AMPA receptor trafficking. Furthermore, active-forgetting employs network level mechanisms wherein non-engram neurons, newly born-engram neurons, and glial cells regulate engram synapses in a state and experience dependent manner. Remarkably, there is evidence for potential coordination between the network and cellular level forgetting mechanisms. Finally, subjects with several neuropsychiatric diseases have been tested and shown to be impaired in active forgetting. Insights obtained from research on active forgetting in animal models will continue to enrich our understanding of the brain dysfunctions that occur in neuropsychiatric diseases.
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Affiliation(s)
- Jacob A Berry
- Department of Biological Sciences, University of Alberta, Edmonton, AL, T6G 2E9, Canada.
| | - Dana C Guhle
- Department of Biological Sciences, University of Alberta, Edmonton, AL, T6G 2E9, Canada
| | - Ronald L Davis
- Department of Neuroscience, UF Scripps Institute for Biomedical Innovation & Technology, 130 Scripps Way, Jupiter, FL, 33458, USA.
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2
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Chiang MH, Lin YC, Wu T, Wu CL. Thermosensation and Temperature Preference: From Molecules to Neuronal Circuits in Drosophila. Cells 2023; 12:2792. [PMID: 38132112 PMCID: PMC10741703 DOI: 10.3390/cells12242792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 12/01/2023] [Accepted: 12/06/2023] [Indexed: 12/23/2023] Open
Abstract
Temperature has a significant effect on all physiological processes of animals. Suitable temperatures promote responsiveness, movement, metabolism, growth, and reproduction in animals, whereas extreme temperatures can cause injury or even death. Thus, thermosensation is important for survival in all animals. However, mechanisms regulating thermosensation remain unexplored, mostly because of the complexity of mammalian neural circuits. The fruit fly Drosophila melanogaster achieves a desirable body temperature through ambient temperature fluctuations, sunlight exposure, and behavioral strategies. The availability of extensive genetic tools and resources for studying Drosophila have enabled scientists to unravel the mechanisms underlying their temperature preference. Over the past 20 years, Drosophila has become an ideal model for studying temperature-related genes and circuits. This review provides a comprehensive overview of our current understanding of thermosensation and temperature preference in Drosophila. It encompasses various aspects, such as the mechanisms by which flies sense temperature, the effects of internal and external factors on temperature preference, and the adaptive strategies employed by flies in extreme-temperature environments. Understanding the regulating mechanisms of thermosensation and temperature preference in Drosophila can provide fundamental insights into the underlying molecular and neural mechanisms that control body temperature and temperature-related behavioral changes in other animals.
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Affiliation(s)
- Meng-Hsuan Chiang
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan; (M.-H.C.); (Y.-C.L.)
| | - Yu-Chun Lin
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan; (M.-H.C.); (Y.-C.L.)
| | - Tony Wu
- Department of Neurology, New Taipei Municipal TuCheng Hospital, Chang Gung Memorial Hospital, New Taipei City 23652, Taiwan;
| | - Chia-Lin Wu
- Department of Neurology, New Taipei Municipal TuCheng Hospital, Chang Gung Memorial Hospital, New Taipei City 23652, Taiwan;
- Department of Biochemistry, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
- Brain Research Center, National Tsing Hua University, Hsinchu 30013, Taiwan
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3
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Kato A, Ohta K, Okanoya K, Kazama H. Dopaminergic neurons dynamically update sensory values during olfactory maneuver. Cell Rep 2023; 42:113122. [PMID: 37757823 DOI: 10.1016/j.celrep.2023.113122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 07/29/2023] [Accepted: 08/25/2023] [Indexed: 09/29/2023] Open
Abstract
Dopaminergic neurons (DANs) drive associative learning to update the value of sensory cues, but their contribution to the assessment of sensory values outside the context of association remains largely unexplored. Here, we show in Drosophila that DANs in the mushroom body encode the innate value of odors and constantly update the current value by inducing plasticity during olfactory maneuver. Our connectome-based network model linking all the way from the olfactory neurons to DANs reproduces the characteristics of DAN responses, proposing a concrete circuit mechanism for computation. Downstream of DANs, odors alone induce value- and dopamine-dependent changes in the activity of mushroom body output neurons, which store the current value of odors. Consistent with this neural plasticity, specific sets of DANs bidirectionally modulate flies' steering in a virtual olfactory environment. Thus, the DAN circuit known for discrete, associative learning also continuously updates odor values in a nonassociative manner.
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Affiliation(s)
- Ayaka Kato
- RIKEN Center for Brain Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan; Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan
| | - Kazumi Ohta
- RIKEN Center for Brain Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan; RIKEN CBS-KAO Collaboration Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Kazuo Okanoya
- Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan
| | - Hokto Kazama
- RIKEN Center for Brain Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan; Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan; RIKEN CBS-KAO Collaboration Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
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4
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Chiang MH, Lin YC, Chen SF, Lee PS, Fu TF, Wu T, Wu CL. Independent insulin signaling modulators govern hot avoidance under different feeding states. PLoS Biol 2023; 21:e3002332. [PMID: 37847673 PMCID: PMC10581474 DOI: 10.1371/journal.pbio.3002332] [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: 04/16/2023] [Accepted: 09/11/2023] [Indexed: 10/19/2023] Open
Abstract
Thermosensation is critical for the survival of animals. However, mechanisms through which nutritional status modulates thermosensation remain unclear. Herein, we showed that hungry Drosophila exhibit a strong hot avoidance behavior (HAB) compared to food-sated flies. We identified that hot stimulus increases the activity of α'β' mushroom body neurons (MBns), with weak activity in the sated state and strong activity in the hungry state. Furthermore, we showed that α'β' MBn receives the same level of hot input from the mALT projection neurons via cholinergic transmission in sated and hungry states. Differences in α'β' MBn activity between food-sated and hungry flies following heat stimuli are regulated by distinct Drosophila insulin-like peptides (Dilps). Dilp2 is secreted by insulin-producing cells (IPCs) and regulates HAB during satiety, whereas Dilp6 is secreted by the fat body and regulates HAB during the hungry state. We observed that Dilp2 induces PI3K/AKT signaling, whereas Dilp6 induces Ras/ERK signaling in α'β' MBn to regulate HAB in different feeding conditions. Finally, we showed that the 2 α'β'-related MB output neurons (MBONs), MBON-α'3 and MBON-β'1, are necessary for the output of integrated hot avoidance information from α'β' MBn. Our results demonstrate the presence of dual insulin modulation pathways in α'β' MBn, which are important for suitable behavioral responses in Drosophila during thermoregulation under different feeding states.
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Affiliation(s)
- Meng-Hsuan Chiang
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Yu-Chun Lin
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Sheng-Fu Chen
- NHRI Institute of Biomedical Engineering & Nanomedicine, Miaoli, Taiwan
| | - Peng-Shiuan Lee
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Tsai-Feng Fu
- Department of Applied Chemistry, National Chi Nan University, Nantou, Taiwan
| | - Tony Wu
- Department of Neurology, New Taipei Municipal TuCheng Hospital, Chang Gung Memorial Hospital, New Taipei City, Taiwan
| | - Chia-Lin Wu
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
- Department of Neurology, New Taipei Municipal TuCheng Hospital, Chang Gung Memorial Hospital, New Taipei City, Taiwan
- Department of Biochemistry, College of Medicine, Chang Gung University, Taoyuan, Taiwan
- Brain Research Center, National Tsing Hua University, Hsinchu, Taiwan
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5
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Marquis M, Wilson RI. Locomotor and olfactory responses in dopamine neurons of the Drosophila superior-lateral brain. Curr Biol 2022; 32:5406-5414.e5. [PMID: 36450284 DOI: 10.1016/j.cub.2022.11.008] [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: 06/24/2022] [Revised: 08/17/2022] [Accepted: 11/03/2022] [Indexed: 12/03/2022]
Abstract
The Drosophila brain contains about 50 distinct morphological types of dopamine neurons.1,2,3,4 Physiological studies of Drosophila dopamine neurons have been largely limited to one brain region, the mushroom body,5,6,7,8,9,10,11,12,13 where they are implicated in learning.14,15,16,17,18 By comparison, we know little about the physiology of other Drosophila dopamine neurons. Interestingly, a recent whole-brain imaging study found that dopamine neuron activity in several fly brain regions is correlated with locomotion.19 This is notable because many dopamine neurons in the rodent brain are also correlated with locomotion or other movements20,21,22,23,24,25,26,27,28,29,30; however, most rodent studies have focused on learned and rewarded behaviors, and few have investigated dopamine neuron activity during spontaneous (self-timed) movements. In this study, we monitored dopamine neurons in the Drosophila brain during self-timed locomotor movements, focusing on several previously uncharacterized cell types that arborize in the superior-lateral brain, specifically the lateral horn and superior-lateral protocerebrum. We found that activity of all of these dopamine neurons correlated with spontaneous fluctuations in walking speed, with different cell types showing different speed correlations. Some dopamine neurons also responded to odors, but these responses were suppressed by repeated odor encounters. Finally, we found that the same identifiable dopamine neuron can encode different combinations of locomotion and odor in different individuals. If these dopamine neurons promote synaptic plasticity-like the dopamine neurons of the mushroom body-then, their tuning profiles would imply that plasticity depends on a flexible integration of sensory signals, motor signals, and recent experience.
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Affiliation(s)
- Michael Marquis
- Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA
| | - Rachel I Wilson
- Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA.
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6
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Stahl A, Noyes NC, Boto T, Botero V, Broyles CN, Jing M, Zeng J, King LB, Li Y, Davis RL, Tomchik SM. Associative learning drives longitudinally graded presynaptic plasticity of neurotransmitter release along axonal compartments. eLife 2022; 11:e76712. [PMID: 35285796 PMCID: PMC8956283 DOI: 10.7554/elife.76712] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 03/11/2022] [Indexed: 12/27/2022] Open
Abstract
Anatomical and physiological compartmentalization of neurons is a mechanism to increase the computational capacity of a circuit, and a major question is what role axonal compartmentalization plays. Axonal compartmentalization may enable localized, presynaptic plasticity to alter neuronal output in a flexible, experience-dependent manner. Here, we show that olfactory learning generates compartmentalized, bidirectional plasticity of acetylcholine release that varies across the longitudinal compartments of Drosophila mushroom body (MB) axons. The directionality of the learning-induced plasticity depends on the valence of the learning event (aversive vs. appetitive), varies linearly across proximal to distal compartments following appetitive conditioning, and correlates with learning-induced changes in downstream mushroom body output neurons (MBONs) that modulate behavioral action selection. Potentiation of acetylcholine release was dependent on the CaV2.1 calcium channel subunit cacophony. In addition, contrast between the positive conditioned stimulus and other odors required the inositol triphosphate receptor, which maintained responsivity to odors upon repeated presentations, preventing adaptation. Downstream from the MB, a set of MBONs that receive their input from the γ3 MB compartment were required for normal appetitive learning, suggesting that they represent a key node through which reward learning influences decision-making. These data demonstrate that learning drives valence-correlated, compartmentalized, bidirectional potentiation, and depression of synaptic neurotransmitter release, which rely on distinct mechanisms and are distributed across axonal compartments in a learning circuit.
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Affiliation(s)
- Aaron Stahl
- Department of Neuroscience, The Scripps Research InstituteJupiterUnited States
| | - Nathaniel C Noyes
- Department of Neuroscience, The Scripps Research InstituteJupiterUnited States
| | - Tamara Boto
- Department of Neuroscience, The Scripps Research InstituteJupiterUnited States
| | - Valentina Botero
- Department of Neuroscience, The Scripps Research InstituteJupiterUnited States
| | - Connor N Broyles
- Department of Neuroscience, The Scripps Research InstituteJupiterUnited States
| | - Miao Jing
- Chinese Institute for Brain ResearchBeijingChina
| | - Jianzhi Zeng
- Peking-Tsinghua Center for Life Sciences, Peking UniversityBeijingChina
- State Key Laboratory of Membrane Biology, Peking University School of Life SciencesBeijingChina
- PKU IDG/McGovern Institute for Brain ResearchBeijingChina
| | - Lanikea B King
- Department of Neuroscience, The Scripps Research InstituteJupiterUnited States
| | - Yulong Li
- Chinese Institute for Brain ResearchBeijingChina
- Peking-Tsinghua Center for Life Sciences, Peking UniversityBeijingChina
- State Key Laboratory of Membrane Biology, Peking University School of Life SciencesBeijingChina
- PKU IDG/McGovern Institute for Brain ResearchBeijingChina
| | - Ronald L Davis
- Department of Neuroscience, The Scripps Research InstituteJupiterUnited States
| | - Seth M Tomchik
- Department of Neuroscience, The Scripps Research InstituteJupiterUnited States
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7
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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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8
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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: 24] [Impact Index Per Article: 8.0] [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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9
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Buhl E, Kottler B, Hodge JJL, Hirth F. Thermoresponsive motor behavior is mediated by ring neuron circuits in the central complex of Drosophila. Sci Rep 2021; 11:155. [PMID: 33420240 PMCID: PMC7794218 DOI: 10.1038/s41598-020-80103-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 12/11/2020] [Indexed: 02/05/2023] Open
Abstract
Insects are ectothermal animals that are constrained in their survival and reproduction by external temperature fluctuations which require either active avoidance of or movement towards a given heat source. In Drosophila, different thermoreceptors and neurons have been identified that mediate temperature sensation to maintain the animal’s thermal preference. However, less is known how thermosensory information is integrated to gate thermoresponsive motor behavior. Here we use transsynaptic tracing together with calcium imaging, electrophysiology and thermogenetic manipulations in freely moving Drosophila exposed to elevated temperature and identify different functions of ellipsoid body ring neurons, R1-R4, in thermoresponsive motor behavior. Our results show that warming of the external surroundings elicits calcium influx specifically in R2-R4 but not in R1, which evokes threshold-dependent neural activity in the outer layer ring neurons. In contrast to R2, R3 and R4d neurons, thermogenetic inactivation of R4m and R1 neurons expressing the temperature-sensitive mutant allele of dynamin, shibireTS, results in impaired thermoresponsive motor behavior at elevated 31 °C. trans-Tango mediated transsynaptic tracing together with physiological and behavioral analyses indicate that integrated sensory information of warming is registered by neural activity of R4m as input layer of the ellipsoid body ring neuropil and relayed on to R1 output neurons that gate an adaptive motor response. Together these findings imply that segregated activities of central complex ring neurons mediate sensory-motor transformation of external temperature changes and gate thermoresponsive motor behavior in Drosophila.
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Affiliation(s)
- Edgar Buhl
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, University Walk, Bristol, UK.
| | - Benjamin Kottler
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - James J L Hodge
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, University Walk, Bristol, UK
| | - Frank Hirth
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK.
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10
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Siju KP, De Backer JF, Grunwald Kadow IC. Dopamine modulation of sensory processing and adaptive behavior in flies. Cell Tissue Res 2021; 383:207-225. [PMID: 33515291 PMCID: PMC7873103 DOI: 10.1007/s00441-020-03371-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 11/26/2020] [Indexed: 12/31/2022]
Abstract
Behavioral flexibility for appropriate action selection is an advantage when animals are faced with decisions that will determine their survival or death. In order to arrive at the right decision, animals evaluate information from their external environment, internal state, and past experiences. How these different signals are integrated and modulated in the brain, and how context- and state-dependent behavioral decisions are controlled are poorly understood questions. Studying the molecules that help convey and integrate such information in neural circuits is an important way to approach these questions. Many years of work in different model organisms have shown that dopamine is a critical neuromodulator for (reward based) associative learning. However, recent findings in vertebrates and invertebrates have demonstrated the complexity and heterogeneity of dopaminergic neuron populations and their functional implications in many adaptive behaviors important for survival. For example, dopaminergic neurons can integrate external sensory information, internal and behavioral states, and learned experience in the decision making circuitry. Several recent advances in methodologies and the availability of a synaptic level connectome of the whole-brain circuitry of Drosophila melanogaster make the fly an attractive system to study the roles of dopamine in decision making and state-dependent behavior. In particular, a learning and memory center-the mushroom body-is richly innervated by dopaminergic neurons that enable it to integrate multi-modal information according to state and context, and to modulate decision-making and behavior.
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Affiliation(s)
- K. P. Siju
- School of Life Sciences, Department of Molecular Life Sciences, Technical University of Munich, 85354 Freising, Germany
| | - Jean-Francois De Backer
- School of Life Sciences, Department of Molecular Life Sciences, Technical University of Munich, 85354 Freising, Germany
| | - Ilona C. Grunwald Kadow
- School of Life Sciences, Department of Molecular Life Sciences, Technical University of Munich, 85354 Freising, Germany
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11
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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: 183] [Impact Index Per Article: 45.8] [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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12
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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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13
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Lubawy J, Urbański A, Colinet H, Pflüger HJ, Marciniak P. Role of the Insect Neuroendocrine System in the Response to Cold Stress. Front Physiol 2020; 11:376. [PMID: 32390871 PMCID: PMC7190868 DOI: 10.3389/fphys.2020.00376] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 03/30/2020] [Indexed: 12/25/2022] Open
Abstract
Insects are the largest group of animals. They are capable of surviving in virtually all environments from arid deserts to the freezing permafrost of polar regions. This success is due to their great capacity to tolerate a range of environmental stresses, such as low temperature. Cold/freezing stress affects many physiological processes in insects, causing changes in main metabolic pathways, cellular dehydration, loss of neuromuscular function, and imbalance in water and ion homeostasis. The neuroendocrine system and its related signaling mediators, such as neuropeptides and biogenic amines, play central roles in the regulation of the various physiological and behavioral processes of insects and hence can also potentially impact thermal tolerance. In response to cold stress, various chemical signals are released either via direct intercellular contact or systemically. These are signals which regulate osmoregulation - capability peptides (CAPA), inotocin (ITC)-like peptides, ion transport peptide (ITP), diuretic hormones and calcitonin (CAL), substances related to the general response to various stress factors - tachykinin-related peptides (TRPs) or peptides responsible for the mobilization of body reserves. All these processes are potentially important in cold tolerance mechanisms. This review summarizes the current knowledge on the involvement of the neuroendocrine system in the cold stress response and the possible contributions of various signaling molecules in this process.
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Affiliation(s)
- Jan Lubawy
- Department of Animal Physiology and Development, Faculty of Biology, Institute of Experimental Biology, Adam Mickiewicz University Poznań, Poznań, Poland
| | - Arkadiusz Urbański
- Department of Animal Physiology and Development, Faculty of Biology, Institute of Experimental Biology, Adam Mickiewicz University Poznań, Poznań, Poland
- HiProMine S.A., Robakowo, Poland
| | - Hervé Colinet
- ECOBIO – UMR 6553, Université de Rennes 1, CNRS, Rennes, France
| | | | - Paweł Marciniak
- Department of Animal Physiology and Development, Faculty of Biology, Institute of Experimental Biology, Adam Mickiewicz University Poznań, Poznań, Poland
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14
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Aso Y, Ray RP, Long X, Bushey D, Cichewicz K, Ngo TT, Sharp B, Christoforou C, Hu A, Lemire AL, Tillberg P, Hirsh J, Litwin-Kumar A, Rubin GM. Nitric oxide acts as a cotransmitter in a subset of dopaminergic neurons to diversify memory dynamics. eLife 2019; 8:49257. [PMID: 31724947 PMCID: PMC6948953 DOI: 10.7554/elife.49257] [Citation(s) in RCA: 76] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Accepted: 11/13/2019] [Indexed: 12/31/2022] Open
Abstract
Animals employ diverse learning rules and synaptic plasticity dynamics to record temporal and statistical information about the world. However, the molecular mechanisms underlying this diversity are poorly understood. The anatomically defined compartments of the insect mushroom body function as parallel units of associative learning, with different learning rates, memory decay dynamics and flexibility (Aso and Rubin, 2016). Here, we show that nitric oxide (NO) acts as a neurotransmitter in a subset of dopaminergic neurons in Drosophila. NO's effects develop more slowly than those of dopamine and depend on soluble guanylate cyclase in postsynaptic Kenyon cells. NO acts antagonistically to dopamine; it shortens memory retention and facilitates the rapid updating of memories. The interplay of NO and dopamine enables memories stored in local domains along Kenyon cell axons to be specialized for predicting the value of odors based only on recent events. Our results provide key mechanistic insights into how diverse memory dynamics are established in parallel memory systems.
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Affiliation(s)
- Yoshinori Aso
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Robert P Ray
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Xi Long
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Daniel Bushey
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Karol Cichewicz
- Department of Biology, University of Virginia, Charlottesville, United States
| | - Teri-Tb Ngo
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Brandi Sharp
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | | | - Amy Hu
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Andrew L Lemire
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Paul Tillberg
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Jay Hirsh
- Department of Biology, University of Virginia, Charlottesville, United States
| | - Ashok Litwin-Kumar
- Department of Neuroscience, Columbia University, New York, United States
| | - Gerald M Rubin
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
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15
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Grunwald Kadow IC. State-dependent plasticity of innate behavior in fruit flies. Curr Opin Neurobiol 2018; 54:60-65. [PMID: 30219668 DOI: 10.1016/j.conb.2018.08.014] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 08/28/2018] [Indexed: 01/27/2023]
Abstract
Behaviors are often categorized into innate or learned. Innate behaviors are thought to be genetically encoded and hardwired into the brain, while learned behavior is a product of the interaction between experience and the plasticity of synapses and neurons. Recent work in different models show that innate behavior, too, is plastic and depends on the current behavioral context and the internal state of an animal. Furthermore, these studies suggest that the neural circuits underpinning innate and learned behavior interact and even overlap. For instance, hunger modulates several innate behaviors relying in part on neural circuits required for learning and memory such as the mushroom body in the fruit fly. These new findings suggest that state-dependent innate behavior and learning rely on functionally and anatomically overlapping and shared neural circuits indicating a common evolutionary history.
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Affiliation(s)
- Ilona C Grunwald Kadow
- Technical University of Munich, School of Life Sciences, ZIEL, Liesel-Beckmann-Str. 4, 85354, Freising, Germany.
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16
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dSTIM- and Ral/Exocyst-Mediated Synaptic Release from Pupal Dopaminergic Neurons Sustains Drosophila Flight. eNeuro 2018; 5:eN-NWR-0455-17. [PMID: 29938216 PMCID: PMC6011419 DOI: 10.1523/eneuro.0455-17.2018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Revised: 05/06/2018] [Accepted: 05/07/2018] [Indexed: 12/13/2022] Open
Abstract
Manifestation of appropriate behavior in adult animals requires developmental mechanisms that help in the formation of correctly wired neural circuits. Flight circuit development in Drosophila requires store-operated calcium entry (SOCE) through the STIM/Orai pathway. SOCE-associated flight deficits in adult Drosophila derive extensively from regulation of gene expression in pupal neurons, and one such SOCE-regulated gene encodes the small GTPase Ral. The cellular mechanism by which Ral helps in maturation of the flight circuit was not understood. Here, we show that knockdown of components of a Ral effector, the exocyst complex, in pupal neurons also leads to reduced flight bout durations, and this phenotype derives primarily from dopaminergic neurons. Importantly, synaptic release from pupal dopaminergic neurons is abrogated upon knockdown of dSTIM, Ral, or exocyst components. Ral overexpression restores the diminished synaptic release of dStim knockdown neurons as well as flight deficits associated with dSTIM knockdown in dopaminergic neurons. These results identify Ral-mediated vesicular release as an effector mechanism of neuronal SOCE in pupal dopaminergic neurons with functional consequences on flight behavior.
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17
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Cyclic AMP-dependent plasticity underlies rapid changes in odor coding associated with reward learning. Proc Natl Acad Sci U S A 2017; 115:E448-E457. [PMID: 29284750 DOI: 10.1073/pnas.1709037115] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Learning and memory rely on dopamine and downstream cAMP-dependent plasticity across diverse organisms. Despite the central role of cAMP signaling, it is not known how cAMP-dependent plasticity drives coherent changes in neuronal physiology that encode the memory trace, or engram. In Drosophila, the mushroom body (MB) is critically involved in olfactory classical conditioning, and cAMP signaling molecules are necessary and sufficient for normal memory in intrinsic MB neurons. To evaluate the role of cAMP-dependent plasticity in learning, we examined how cAMP manipulations and olfactory classical conditioning modulate olfactory responses in the MB with in vivo imaging. Elevating cAMP pharmacologically or optogenetically produced plasticity in MB neurons, altering their responses to odorants. Odor-evoked Ca2+ responses showed net facilitation across anatomical regions. At the single-cell level, neurons exhibited heterogeneous responses to cAMP elevation, suggesting that cAMP drives plasticity to discrete subsets of MB neurons. Olfactory appetitive conditioning enhanced MB odor responses, mimicking the cAMP-dependent plasticity in directionality and magnitude. Elevating cAMP to equivalent levels as appetitive conditioning also produced plasticity, suggesting that the cAMP generated during conditioning affects odor-evoked responses in the MB. Finally, we found that this plasticity was dependent on the Rutabaga type I adenylyl cyclase, linking cAMP-dependent plasticity to behavioral modification. Overall, these data demonstrate that learning produces robust cAMP-dependent plasticity in intrinsic MB neurons, which is biased toward naturalistic reward learning. This suggests that cAMP signaling may serve to modulate intrinsic MB responses toward salient stimuli.
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18
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Cervantes-Sandoval I, Phan A, Chakraborty M, Davis RL. Reciprocal synapses between mushroom body and dopamine neurons form a positive feedback loop required for learning. eLife 2017; 6. [PMID: 28489528 PMCID: PMC5425253 DOI: 10.7554/elife.23789] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 04/30/2017] [Indexed: 11/22/2022] Open
Abstract
Current thought envisions dopamine neurons conveying the reinforcing effect of the unconditioned stimulus during associative learning to the axons of Drosophila mushroom body Kenyon cells for normal olfactory learning. Here, we show using functional GFP reconstitution experiments that Kenyon cells and dopamine neurons from axoaxonic reciprocal synapses. The dopamine neurons receive cholinergic input via nicotinic acetylcholine receptors from the Kenyon cells; knocking down these receptors impairs olfactory learning revealing the importance of these receptors at the synapse. Blocking the synaptic output of Kenyon cells during olfactory conditioning reduces presynaptic calcium transients in dopamine neurons, a finding consistent with reciprocal communication. Moreover, silencing Kenyon cells decreases the normal chronic activity of the dopamine neurons. Our results reveal a new and critical role for positive feedback onto dopamine neurons through reciprocal connections with Kenyon cells for normal olfactory learning. DOI:http://dx.doi.org/10.7554/eLife.23789.001
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Affiliation(s)
| | - Anna Phan
- Department of Neuroscience, The Scripps Research Institute Florida, Jupiter, United States
| | - Molee Chakraborty
- Department of Neuroscience, The Scripps Research Institute Florida, Jupiter, United States
| | - Ronald L Davis
- Department of Neuroscience, The Scripps Research Institute Florida, Jupiter, United States
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19
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Li K, Gong Z. Feeling Hot and Cold: Thermal Sensation in Drosophila. Neurosci Bull 2016; 33:317-322. [PMID: 27995563 DOI: 10.1007/s12264-016-0087-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 10/31/2016] [Indexed: 10/20/2022] Open
Abstract
Sensing environmental temperature is crucial for animal life. The model animal, Drosophila melanogaster, can be investigated with a large number of genetic tools, which have greatly facilitated studies of the cellular and molecular mechanisms of thermal sensing. At the molecular level, a group of proteins, including Transient Receptor Potential channels and ionotropic receptors, have been characterized as potential thermal sensors in both larval and adult Drosophila. At the cellular and circuit levels, peripheral and central thermosensory neurons have been identified. More interestingly, thermal information has been found to be specifically encoded by specific central neurons. In this short review, we mainly survey the progress in understanding the molecular mechanisms of thermosensation and the neuronal mechanisms of thermal information processing in the brain of Drosophila. Other recent temperature-related findings such as its impact on neurosecretion and thermotactic behavior in Drosophila are also introduced.
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Affiliation(s)
- Kun Li
- Department of Neurobiology, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Zhefeng Gong
- Department of Neurobiology, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang University School of Medicine, Hangzhou, 310058, China.
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20
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Aso Y, Rubin GM. Dopaminergic neurons write and update memories with cell-type-specific rules. eLife 2016; 5:e16135. [PMID: 27441388 PMCID: PMC4987137 DOI: 10.7554/elife.16135] [Citation(s) in RCA: 162] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 07/18/2016] [Indexed: 12/13/2022] Open
Abstract
Associative learning is thought to involve parallel and distributed mechanisms of memory formation and storage. In Drosophila, the mushroom body (MB) is the major site of associative odor memory formation. Previously we described the anatomy of the adult MB and defined 20 types of dopaminergic neurons (DANs) that each innervate distinct MB compartments (Aso et al., 2014a, 2014b). Here we compare the properties of memories formed by optogenetic activation of individual DAN cell types. We found extensive differences in training requirements for memory formation, decay dynamics, storage capacity and flexibility to learn new associations. Even a single DAN cell type can either write or reduce an aversive memory, or write an appetitive memory, depending on when it is activated relative to odor delivery. Our results show that different learning rules are executed in seemingly parallel memory systems, providing multiple distinct circuit-based strategies to predict future events from past experiences.
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Affiliation(s)
- Yoshinori Aso
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Gerald M Rubin
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
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21
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Li Q, Gong Z. Cold-sensing regulates Drosophila growth through insulin-producing cells. Nat Commun 2015; 6:10083. [PMID: 26648410 PMCID: PMC4682036 DOI: 10.1038/ncomms10083] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 10/30/2015] [Indexed: 11/09/2022] Open
Abstract
Across phyla, body size is linked to climate. For example, rearing fruit flies at lower temperatures results in bigger body sizes than those observed at higher temperatures. The underlying molecular basis of this effect is poorly understood. Here we provide evidence that the temperature-dependent regulation of Drosophila body size depends on a group of cold-sensing neurons and insulin-producing cells (IPCs). Electrically silencing IPCs completely abolishes the body size increase induced by cold temperature. IPCs are directly innervated by cold-sensing neurons. Stimulation of these cold-sensing neurons activates IPCs, promotes synthesis and secretion of Drosophila insulin-like peptides and induces a larger body size, mimicking the effects of rearing the flies in cold temperature. Taken together, these findings reveal a neuronal circuit that mediates the effects of low temperature on fly growth.
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Affiliation(s)
- Qiaoran Li
- Department of Neurobiology, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Key Laboratory of Neurobiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Zhefeng Gong
- Department of Neurobiology, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Key Laboratory of Neurobiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
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22
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Lewis L, Siju K, Aso Y, Friedrich A, Bulteel A, Rubin G, Grunwald Kadow I. A Higher Brain Circuit for Immediate Integration of Conflicting Sensory Information in Drosophila. Curr Biol 2015; 25:2203-14. [DOI: 10.1016/j.cub.2015.07.015] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Revised: 06/18/2015] [Accepted: 07/06/2015] [Indexed: 10/23/2022]
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23
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Abstract
The Drosophila mushroom bodies are critical association areas whose role in olfactory associative learning has been well characterized. Recent behavioral studies using a taste association paradigm revealed that gustatory conditioning also requires the mushroom bodies (Masek and Scott, 2010; Keene and Masek, 2012). Here, we examine the representations of tastes and the neural sites for taste associations in the mushroom bodies. Using molecular genetic approaches to target different neuronal populations, we find that the gamma lobes of the mushroom bodies and a subset of dopaminergic input neurons are required for taste associative learning. Monitoring responses to taste compounds in the mushroom body calyx with calcium imaging reveals sparse, taste-specific and organ-specific activation in the Kenyon cell dendrites of the main calyx and the dorsal accessory calyx. Our work provides insight into gustatory representations in the mushroom bodies, revealing the essential role of gustatory inputs not only as rewards and punishments but also as adaptive cues.
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24
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Berry JA, Cervantes-Sandoval I, Chakraborty M, Davis RL. Sleep Facilitates Memory by Blocking Dopamine Neuron-Mediated Forgetting. Cell 2015; 161:1656-67. [PMID: 26073942 DOI: 10.1016/j.cell.2015.05.027] [Citation(s) in RCA: 148] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Revised: 02/27/2015] [Accepted: 04/20/2015] [Indexed: 01/10/2023]
Abstract
Early studies from psychology suggest that sleep facilitates memory retention by stopping ongoing retroactive interference caused by mental activity or external sensory stimuli. Neuroscience research with animal models, on the other hand, suggests that sleep facilitates retention by enhancing memory consolidation. Recently, in Drosophila, the ongoing activity of specific dopamine neurons was shown to regulate the forgetting of olfactory memories. Here, we show this ongoing dopaminergic activity is modulated with behavioral state, increasing robustly with locomotor activity and decreasing with rest. Increasing sleep-drive, with either the sleep-promoting agent Gaboxadol or by genetic stimulation of the neural circuit for sleep, decreases ongoing dopaminergic activity, while enhancing memory retention. Conversely, increasing arousal stimulates ongoing dopaminergic activity and accelerates dopaminergic-based forgetting. Therefore, forgetting is regulated by the behavioral state modulation of dopaminergic-based plasticity. Our findings integrate psychological and neuroscience research on sleep and forgetting.
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Affiliation(s)
- Jacob A Berry
- Department of Neuroscience, Scripps Research Institute Florida, Jupiter, FL 33458, USA
| | | | - Molee Chakraborty
- Department of Neuroscience, Scripps Research Institute Florida, Jupiter, FL 33458, USA
| | - Ronald L Davis
- Department of Neuroscience, Scripps Research Institute Florida, Jupiter, FL 33458, USA.
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25
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Head LM, Tang X, Hayley SE, Goda T, Umezaki Y, Chang EC, Leslie JR, Fujiwara M, Garrity PA, Hamada FN. The influence of light on temperature preference in Drosophila. Curr Biol 2015; 25:1063-8. [PMID: 25866391 DOI: 10.1016/j.cub.2015.02.038] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 01/12/2015] [Accepted: 02/13/2015] [Indexed: 10/23/2022]
Abstract
Ambient light affects multiple physiological functions and behaviors, such as circadian rhythms, sleep-wake activities, and development, from flies to mammals. Mammals exhibit a higher body temperature when exposed to acute light compared to when they are exposed to the dark, but the underlying mechanisms are largely unknown. The body temperature of small ectotherms, such as Drosophila, relies on the temperature of their surrounding environment, and these animals exhibit a robust temperature preference behavior. Here, we demonstrate that Drosophila prefer a ∼1° higher temperature when exposed to acute light rather than the dark. This acute light response, light-dependent temperature preference (LDTP), was observed regardless of the time of day, suggesting that LDTP is regulated separately from the circadian clock. However, screening of eye and circadian clock mutants suggests that the circadian clock neurons posterior dorsal neurons 1 (DN1(p)s) and Pigment-Dispersing Factor Receptor (PDFR) play a role in LDTP. To further investigate the role of DN1(p)s in LDTP, PDFR in DN1(p)s was knocked down, resulting in an abnormal LDTP. The phenotype of the pdfr mutant was rescued sufficiently by expressing PDFR in DN1(p)s, indicating that PDFR in DN1(p)s is responsible for LDTP. These results suggest that light positively influences temperature preference via the circadian clock neurons, DN1(p)s, which may result from the integration of light and temperature information. Given that both Drosophila and mammals respond to acute light by increasing their body temperature, the effect of acute light on temperature regulation may be conserved evolutionarily between flies and humans.
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Affiliation(s)
- Lauren M Head
- Visual Systems Group, Abrahamson Pediatric Eye Institute, Division of Pediatric Ophthalmology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229, USA
| | - Xin Tang
- Visual Systems Group, Abrahamson Pediatric Eye Institute, Division of Pediatric Ophthalmology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229, USA
| | - Sean E Hayley
- Visual Systems Group, Abrahamson Pediatric Eye Institute, Division of Pediatric Ophthalmology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229, USA
| | - Tadahiro Goda
- Visual Systems Group, Abrahamson Pediatric Eye Institute, Division of Pediatric Ophthalmology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229, USA
| | - Yujiro Umezaki
- Visual Systems Group, Abrahamson Pediatric Eye Institute, Division of Pediatric Ophthalmology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229, USA
| | - Elaine C Chang
- Department of Biology, National Center for Behavioral Genomics and Volen Center for Complex Systems, Brandeis University, 415 South Street, Waltham, MA 02458, USA
| | - Jennifer R Leslie
- Visual Systems Group, Abrahamson Pediatric Eye Institute, Division of Pediatric Ophthalmology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229, USA
| | - Mana Fujiwara
- Visual Systems Group, Abrahamson Pediatric Eye Institute, Division of Pediatric Ophthalmology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229, USA
| | - Paul A Garrity
- Department of Biology, National Center for Behavioral Genomics and Volen Center for Complex Systems, Brandeis University, 415 South Street, Waltham, MA 02458, USA
| | - Fumika N Hamada
- Visual Systems Group, Abrahamson Pediatric Eye Institute, Division of Pediatric Ophthalmology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229, USA; Japan Science and Technology Agency, PRESTO, 4-1-8 Honcho Kawaguchi, Saitama 332-0012, Japan; Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Department of Ophthalmology, College of Medicine, University of Cincinnati, Cincinnati, OH 45229, USA.
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26
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Barbagallo B, Garrity PA. Temperature sensation in Drosophila. Curr Opin Neurobiol 2015; 34:8-13. [PMID: 25616212 DOI: 10.1016/j.conb.2015.01.002] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 01/06/2015] [Accepted: 01/06/2015] [Indexed: 12/11/2022]
Abstract
Animals use thermosensory systems to achieve optimal temperatures for growth and reproduction and to avoid damaging extremes. Thermoregulation is particularly challenging for small animals like the fruit fly Drosophila melanogaster, whose body temperature rapidly changes in response to environmental temperature fluctuation. Recent work has uncovered some of the key molecules mediating fly thermosensation, including the Transient Receptor Potential (TRP) channels TRPA1 and Painless, and the Gustatory Receptor Gr28b, an unanticipated thermosensory regulator normally associated with a different sensory modality. There is also evidence the Drosophila phototransduction cascade may have some role in thermosensory responses. Together, the fly's diverse thermosensory molecules act in an array of functionally distinct thermosensory neurons to drive a suite of complex, and often exceptionally thermosensitive, behaviors.
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Affiliation(s)
- Belinda Barbagallo
- National Center for Behavioral Genomics and Volen Center for Complex Systems, Department of Biology, Brandeis University, Waltham, MA 02458, United States
| | - Paul A Garrity
- National Center for Behavioral Genomics and Volen Center for Complex Systems, Department of Biology, Brandeis University, Waltham, MA 02458, United States.
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27
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Aso Y, Hattori D, Yu Y, Johnston RM, Iyer NA, Ngo TTB, Dionne H, Abbott LF, Axel R, Tanimoto H, Rubin GM. The neuronal architecture of the mushroom body provides a logic for associative learning. eLife 2014; 3:e04577. [PMID: 25535793 PMCID: PMC4273437 DOI: 10.7554/elife.04577] [Citation(s) in RCA: 605] [Impact Index Per Article: 60.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 11/05/2014] [Indexed: 12/18/2022] Open
Abstract
We identified the neurons comprising the Drosophila mushroom body (MB), an associative center in invertebrate brains, and provide a comprehensive map describing their potential connections. Each of the 21 MB output neuron (MBON) types elaborates segregated dendritic arbors along the parallel axons of ∼2000 Kenyon cells, forming 15 compartments that collectively tile the MB lobes. MBON axons project to five discrete neuropils outside of the MB and three MBON types form a feedforward network in the lobes. Each of the 20 dopaminergic neuron (DAN) types projects axons to one, or at most two, of the MBON compartments. Convergence of DAN axons on compartmentalized Kenyon cell-MBON synapses creates a highly ordered unit that can support learning to impose valence on sensory representations. The elucidation of the complement of neurons of the MB provides a comprehensive anatomical substrate from which one can infer a functional logic of associative olfactory learning and memory.
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Affiliation(s)
- Yoshinori Aso
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Daisuke Hattori
- Howard Hughes Medical Institute, Columbia University, New York, United States
| | - Yang Yu
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Rebecca M Johnston
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Nirmala A Iyer
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Teri-T B Ngo
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Heather Dionne
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - L F Abbott
- Department of Neuroscience, College of Physicians and Surgeons, Columbia University, New York, United States
| | - Richard Axel
- Howard Hughes Medical Institute, Columbia University, New York, United States
| | - Hiromu Tanimoto
- Tohuku University Graduate School of Life Sciences, Sendai, Japan
| | - Gerald M Rubin
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
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Channelrhodopsin-2-XXL, a powerful optogenetic tool for low-light applications. Proc Natl Acad Sci U S A 2014; 111:13972-7. [PMID: 25201989 DOI: 10.1073/pnas.1408269111] [Citation(s) in RCA: 123] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Channelrhodopsin-2 (ChR2) has provided a breakthrough for the optogenetic control of neuronal activity. In adult Drosophila melanogaster, however, its applications are severely constrained. This limitation in a powerful model system has curtailed unfolding the full potential of ChR2 for behavioral neuroscience. Here, we describe the D156C mutant, termed ChR2-XXL (extra high expression and long open state), which displays increased expression, improved subcellular localization, elevated retinal affinity, an extended open-state lifetime, and photocurrent amplitudes greatly exceeding those of all heretofore published ChR variants. As a result, neuronal activity could be efficiently evoked with ambient light and even without retinal supplementation. We validated the benefits of the variant in intact flies by eliciting simple and complex behaviors. We demonstrate efficient and prolonged photostimulation of monosynaptic transmission at the neuromuscular junction and reliable activation of a gustatory reflex pathway. Innate male courtship was triggered in male and female flies, and olfactory memories were written through light-induced associative training.
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29
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Converging Circuits Mediate Temperature and Shock Aversive Olfactory Conditioning in Drosophila. Curr Biol 2014; 24:1712-22. [DOI: 10.1016/j.cub.2014.06.062] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 05/15/2014] [Accepted: 06/25/2014] [Indexed: 11/20/2022]
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30
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Boto T, Louis T, Jindachomthong K, Jalink K, Tomchik SM. Dopaminergic modulation of cAMP drives nonlinear plasticity across the Drosophila mushroom body lobes. Curr Biol 2014; 24:822-31. [PMID: 24684937 DOI: 10.1016/j.cub.2014.03.021] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Revised: 02/11/2014] [Accepted: 03/07/2014] [Indexed: 01/21/2023]
Abstract
BACKGROUND Activity of dopaminergic neurons is necessary and sufficient to evoke learning-related plasticity in neuronal networks that modulate learning. During olfactory classical conditioning, large subsets of dopaminergic neurons are activated, releasing dopamine across broad sets of postsynaptic neurons. It is unclear how such diffuse dopamine release generates the highly localized patterns of plasticity required for memory formation. RESULTS Here we have mapped spatial patterns of dopaminergic modulation of intracellular signaling and plasticity in Drosophila mushroom body (MB) neurons, combining presynaptic thermogenetic stimulation of dopaminergic neurons with postsynaptic functional imaging in vivo. Stimulation of dopaminergic neurons generated increases in cyclic AMP (cAMP) across multiple spatial regions in the MB. However, odor presentation paired with stimulation of dopaminergic neurons evoked plasticity in Ca(2+) responses in discrete spatial patterns. These patterns of plasticity correlated with behavioral requirements for each set of MB neurons in aversive and appetitive conditioning. Finally, broad elevation of cAMP differentially facilitated responses in the gamma lobe, suggesting that it is more sensitive to elevations of cAMP and that it is recruited first into dopamine-dependent memory traces. CONCLUSIONS These data suggest that the spatial pattern of learning-related plasticity is dependent on the postsynaptic neurons' sensitivity to cAMP signaling. This may represent a mechanism through which single-cycle conditioning allocates short-term memory to a specific subset of eligible neurons (gamma neurons).
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Affiliation(s)
- Tamara Boto
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Thierry Louis
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | | | - Kees Jalink
- Division of Cell Biology, The Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - Seth M Tomchik
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA.
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