201
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Abstract
In this review, I discuss current knowledge and outstanding questions on the neuromodulators that influence aggressive behavior of the fruit fly Drosophila melanogaster. I first present evidence that Drosophila exchange information during an agonistic interaction and choose appropriate actions based on this information. I then discuss the influence of several biogenic amines and neuropeptides on aggressive behavior. One striking characteristic of neuromodulation is that it can configure a neural circuit dynamically, enabling one circuit to generate multiple outcomes. I suggest a consensus effect of each neuromodulatory molecule on Drosophila aggression, as well as effects of receptor proteins where relevant data are available. Lastly, I consider neuromodulation in the context of strategic action choices during agonistic interactions. Genetic components of neuromodulatory systems are highly conserved across animals, suggesting that molecular and cellular mechanisms controlling Drosophila aggression can shed light on neural principles governing action choice during social interactions.
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Affiliation(s)
- Kenta Asahina
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, La Jolla, California 92037;
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202
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Ueoka Y, Hiroi M, Abe T, Tabata T. Suppression of a single pair of mushroom body output neurons in Drosophila triggers aversive associations. FEBS Open Bio 2017; 7:562-576. [PMID: 28396840 PMCID: PMC5377409 DOI: 10.1002/2211-5463.12203] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2017] [Revised: 01/26/2017] [Accepted: 01/27/2017] [Indexed: 11/14/2022] Open
Abstract
Memory includes the processes of acquisition, consolidation and retrieval. In the study of aversive olfactory memory in Drosophila melanogaster, flies are first exposed to an odor (conditioned stimulus, CS+) that is associated with an electric shock (unconditioned stimulus, US), then to another odor (CS−) without the US, before allowing the flies to choose to avoid one of the two odors. The center for memory formation is the mushroom body which consists of Kenyon cells (KCs), dopaminergic neurons (DANs) and mushroom body output neurons (MBONs). However, the roles of individual neurons are not fully understood. We focused on the role of a single pair of GABAergic neurons (MBON‐γ1pedc) and found that it could inhibit the effects of DANs, resulting in the suppression of aversive memory acquisition during the CS− odor presentation, but not during the CS+ odor presentation. We propose that MBON‐γ1pedc suppresses the DAN‐dependent effect that can convey the aversive US during the CS− odor presentation, and thereby prevents an insignificant stimulus from becoming an aversive US.
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Affiliation(s)
- Yutaro Ueoka
- Department of Biological SciencesGraduate School of ScienceThe University of TokyoBunkyo‐kuJapan
- Institute of Molecular and Cellular BiosciencesThe University of TokyoBunkyo‐kuJapan
| | - Makoto Hiroi
- Institute of Molecular and Cellular BiosciencesThe University of TokyoBunkyo‐kuJapan
| | - Takashi Abe
- Institute of Molecular and Cellular BiosciencesThe University of TokyoBunkyo‐kuJapan
| | - Tetsuya Tabata
- Department of Biological SciencesGraduate School of ScienceThe University of TokyoBunkyo‐kuJapan
- Institute of Molecular and Cellular BiosciencesThe University of TokyoBunkyo‐kuJapan
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203
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Litwin-Kumar A, Harris KD, Axel R, Sompolinsky H, Abbott LF. Optimal Degrees of Synaptic Connectivity. Neuron 2017; 93:1153-1164.e7. [PMID: 28215558 DOI: 10.1016/j.neuron.2017.01.030] [Citation(s) in RCA: 167] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 11/03/2016] [Accepted: 01/30/2017] [Indexed: 10/20/2022]
Abstract
Synaptic connectivity varies widely across neuronal types. Cerebellar granule cells receive five orders of magnitude fewer inputs than the Purkinje cells they innervate, and cerebellum-like circuits, including the insect mushroom body, also exhibit large divergences in connectivity. In contrast, the number of inputs per neuron in cerebral cortex is more uniform and large. We investigate how the dimension of a representation formed by a population of neurons depends on how many inputs each neuron receives and what this implies for learning associations. Our theory predicts that the dimensions of the cerebellar granule-cell and Drosophila Kenyon-cell representations are maximized at degrees of synaptic connectivity that match those observed anatomically, showing that sparse connectivity is sometimes superior to dense connectivity. When input synapses are subject to supervised plasticity, however, dense wiring becomes advantageous, suggesting that the type of plasticity exhibited by a set of synapses is a major determinant of connection density.
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Affiliation(s)
- Ashok Litwin-Kumar
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Department of Neuroscience, Columbia University, New York, NY 10027, USA.
| | | | - Richard Axel
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Department of Neuroscience, Columbia University, New York, NY 10027, USA; Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Howard Hughes Medical Institute, Columbia University, New York, NY 10032, USA
| | - Haim Sompolinsky
- Edmond and Lily Safra Center for Brain Sciences, Hebrew University, Jerusalem 91904, Israel; Racah Institute of Physics, Hebrew University, Jerusalem 91904, Israel; Center for Brain Science, Harvard University, Cambridge, MA 02138, USA
| | - L F Abbott
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Department of Neuroscience, Columbia University, New York, NY 10027, USA; Department of Physiology and Cellular Biophysics, Columbia University, New York, NY 10032, USA
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204
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Kim H, Kirkhart C, Scott K. Long-range projection neurons in the taste circuit of Drosophila. eLife 2017; 6. [PMID: 28164781 PMCID: PMC5310837 DOI: 10.7554/elife.23386] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 02/06/2017] [Indexed: 11/23/2022] Open
Abstract
Taste compounds elicit innate feeding behaviors and act as rewards or punishments to entrain other cues. The neural pathways by which taste compounds influence innate and learned behaviors have not been resolved. Here, we identify three classes of taste projection neurons (TPNs) in Drosophila melanogaster distinguished by their morphology and taste selectivity. TPNs receive input from gustatory receptor neurons and respond selectively to sweet or bitter stimuli, demonstrating segregated processing of different taste modalities. Activation of TPNs influences innate feeding behavior, whereas inhibition has little effect, suggesting parallel pathways. Moreover, two TPN classes are absolutely required for conditioned taste aversion, a learned behavior. The TPNs essential for conditioned aversion project to the superior lateral protocerebrum (SLP) and convey taste information to mushroom body learning centers. These studies identify taste pathways from sensory detection to higher brain that influence innate behavior and are essential for learned responses to taste compounds. DOI:http://dx.doi.org/10.7554/eLife.23386.001
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Affiliation(s)
- Heesoo Kim
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, United States
| | - Colleen Kirkhart
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, United States
| | - Kristin Scott
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, United States
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205
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Dopaminergic rules of engagement for memory in Drosophila. Curr Opin Neurobiol 2017; 43:56-62. [PMID: 28088703 DOI: 10.1016/j.conb.2016.12.011] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 12/20/2016] [Accepted: 12/26/2016] [Indexed: 11/21/2022]
Abstract
Dopamine is associated with a variety of conserved responses across species including locomotion, sleep, food consumption, aggression, courtship, addiction and several forms of appetitive and aversive memory. Historically, dopamine has been most prominently associated with dynamics underlying reward, punishment, or salience. Recent emerging evidence from Drosophila supports a role in all of these functions, as well as additional roles in the interplay between external sensation and internal states and forgetting of the very memories dopamine helped encode. We discuss how cell-specific resolution and manipulation are elucidating the rules of dopamine's involvement in encoding valence and memory.
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206
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Peng F, Chittka L. A Simple Computational Model of the Bee Mushroom Body Can Explain Seemingly Complex Forms of Olfactory Learning and Memory. Curr Biol 2016; 27:224-230. [PMID: 28017607 DOI: 10.1016/j.cub.2016.10.054] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 09/06/2016] [Accepted: 10/26/2016] [Indexed: 10/20/2022]
Abstract
Honeybees are models for studying how animals with relatively small brains accomplish complex cognition, displaying seemingly advanced (or "non-elemental") learning phenomena involving multiple conditioned stimuli. These include "peak shift" [1-4]-where animals not only respond to entrained stimuli, but respond even more strongly to similar ones that are farther away from non-rewarding stimuli. Bees also display negative and positive patterning discrimination [5], responding in opposite ways to mixtures of two odors than to individual odors. Since Pavlov, it has often been assumed that such phenomena are more complex than simple associate learning. We present a model of connections between olfactory sensory input and bees' mushroom bodies [6], incorporating empirically determined properties of mushroom body circuitry (random connectivity [7], sparse coding [8], and synaptic plasticity [9, 10]). We chose not to optimize the model's parameters to replicate specific behavioral phenomena, because we were interested in the emergent cognitive capacities that would pop out of a network constructed solely based on empirical neuroscientific information and plausible assumptions for unknown parameters. We demonstrate that the circuitry mediating "simple" associative learning can also replicate the various non-elemental forms of learning mentioned above and can effectively multi-task by replicating a range of different learning feats. We found that PN-KC synaptic plasticity is crucial in controlling the generalization-discrimination trade-off-it facilitates peak shift and hinders patterning discrimination-and that PN-to-KC connection number can affect this trade-off. These findings question the notion that forms of learning that have been regarded as "higher order" are computationally more complex than "simple" associative learning.
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Affiliation(s)
- Fei Peng
- Biological and Experimental Psychology, School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK
| | - Lars Chittka
- Biological and Experimental Psychology, School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK.
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207
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Bronfman ZZ, Ginsburg S, Jablonka E. The Transition to Minimal Consciousness through the Evolution of Associative Learning. Front Psychol 2016; 7:1954. [PMID: 28066282 PMCID: PMC5177968 DOI: 10.3389/fpsyg.2016.01954] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2016] [Accepted: 11/29/2016] [Indexed: 12/25/2022] Open
Abstract
The minimal state of consciousness is sentience. This includes any phenomenal sensory experience - exteroceptive, such as vision and olfaction; interoceptive, such as pain and hunger; or proprioceptive, such as the sense of bodily position and movement. We propose unlimited associative learning (UAL) as the marker of the evolutionary transition to minimal consciousness (or sentience), its phylogenetically earliest sustainable manifestation and the driver of its evolution. We define and describe UAL at the behavioral and functional level and argue that the structural-anatomical implementations of this mode of learning in different taxa entail subjective feelings (sentience). We end with a discussion of the implications of our proposal for the distribution of consciousness in the animal kingdom, suggesting testable predictions, and revisiting the ongoing debate about the function of minimal consciousness in light of our approach.
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Affiliation(s)
- Zohar Z Bronfman
- The Cohn Institute for the History and Philosophy of Science and Ideas, Tel Aviv UniversityTel Aviv, Israel; School of Psychology, Tel Aviv UniversityTel Aviv, Israel
| | - Simona Ginsburg
- Department of Natural Science, The Open University of Israel Raanana, Israel
| | - Eva Jablonka
- The Cohn Institute for the History and Philosophy of Science and Ideas, Tel Aviv UniversityTel Aviv, Israel; The Sagol School of Neuroscience, Tel Aviv UniversityTel Aviv, Israel
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208
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Liu JL, Chen HL, Chen XY, Cui RK, Guerrero A, Zeng XN. Factors influencing aversive learning in the oriental fruit fly, Bactrocera dorsalis. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2016; 203:57-65. [PMID: 27909789 DOI: 10.1007/s00359-016-1135-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 11/16/2016] [Accepted: 11/17/2016] [Indexed: 10/20/2022]
Abstract
Parameters such as the intensity of conditioned and unconditioned stimuli, the inter-trial interval, and starvation time can influence learning. In this study, the parameters that govern aversive learning in the oriental fruit fly, Bactrocera dorsalis, a serious pest of fruits and vegetables, were examined. Male flies were trained to associate the attractive odorant methyl eugenol, a male lure, with a food punishment, sodium chloride solution, and the conditioned suppression of the proboscis-extension response was investigated. We found that high methyl eugenol concentrations support a stronger association. With increasing concentrations of sodium chloride solution, a steady decrease of proboscis-extension response during six training trials was observed. A high level of learning was achieved with an inter-trial interval of 1-10 min. However, extending the inter-trial interval to 15 min led to reduced learning. No effect of physiological status (starvation time) on learning performance was detected, nor was any non-associative learning effect induced by the repeat presentation of odor or punishment alone. The memory formed after six training trials could be retained for at least 3 h. Our results indicate that aversive learning by oriental fruit flies can be affected by odor, punishment concentration and inter-trial interval.
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Affiliation(s)
- J L Liu
- Key Laboratory of Natural Pesticide and Chemical Biology of the Ministry of Education, College of Agriculture, South China Agricultural University, Guangzhou, Guangdong, China
| | - H L Chen
- Key Laboratory of Natural Pesticide and Chemical Biology of the Ministry of Education, College of Agriculture, South China Agricultural University, Guangzhou, Guangdong, China
| | - X Y Chen
- Key Laboratory of Natural Pesticide and Chemical Biology of the Ministry of Education, College of Agriculture, South China Agricultural University, Guangzhou, Guangdong, China
| | - R K Cui
- Key Laboratory of Natural Pesticide and Chemical Biology of the Ministry of Education, College of Agriculture, South China Agricultural University, Guangzhou, Guangdong, China
| | - A Guerrero
- Department of Biological Chemistry and Molecular Modelling, IQAC (CSIC), Barcelona, Spain
| | - X N Zeng
- Key Laboratory of Natural Pesticide and Chemical Biology of the Ministry of Education, College of Agriculture, South China Agricultural University, Guangzhou, Guangdong, China.
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209
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Cichewicz K, Garren EJ, Adiele C, Aso Y, Wang Z, Wu M, Birman S, Rubin GM, Hirsh J. A new brain dopamine-deficient Drosophila and its pharmacological and genetic rescue. GENES BRAIN AND BEHAVIOR 2016; 16:394-403. [PMID: 27762066 DOI: 10.1111/gbb.12353] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Revised: 10/17/2016] [Accepted: 10/17/2016] [Indexed: 12/12/2022]
Abstract
Dopamine (DA) is a neurotransmitter with conserved behavioral roles between invertebrate and vertebrate animals. In addition to its neural functions, in insects DA is a critical substrate for cuticle pigmentation and hardening. Drosophila tyrosine hydroxylase (DTH) is the rate limiting enzyme for DA biosynthesis. Viable brain DA-deficient flies were previously generated using tissue-selective GAL4-UAS binary expression rescue of a DTH null mutation and these flies show specific behavioral impairments. To circumvent the limitations of rescue via binary expression, here we achieve rescue utilizing genomically integrated mutant DTH. As expected, our DA-deficient flies have no detectable DTH or DA in the brain, and show reduced locomotor activity. This deficit can be rescued by l-DOPA/carbidopa feeding, similar to human Parkinson's disease treatment. Genetic rescue via GAL4/UAS-DTH was also successful, although this required the generation of a new UAS-DTH1 transgene devoid of most untranslated regions, as existing UAS-DTH transgenes express in the brain without a Gal4 driver via endogenous regulatory elements. A surprising finding of our newly constructed UAS-DTH1m is that it expresses DTH at an undetectable level when regulated by dopaminergic GAL4 drivers even when fully rescuing DA, indicating that DTH immunostaining is not necessarily a valid marker for DA expression. This finding necessitated optimizing DA immunohistochemistry, showing details of DA innervation to the mushroom body and the central complex. When DA rescue is limited to specific DA neurons, DA does not diffuse beyond the DTH-expressing terminals, such that DA signaling can be limited to very specific brain regions.
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Affiliation(s)
- K Cichewicz
- Department of Biology, University of Virginia, Charlottesville
| | - E J Garren
- Department of Biology, University of Virginia, Charlottesville
| | - C Adiele
- Department of Biology, University of Virginia, Charlottesville
| | - Y Aso
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Z Wang
- Department of Biology, University of Virginia, Charlottesville
| | - M Wu
- Department of Biology, University of Virginia, Charlottesville
| | - S Birman
- Genes, Circuits, Rhythms and Neuropathology, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, Paris, France
| | - G M Rubin
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - J Hirsh
- Department of Biology, University of Virginia, Charlottesville
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210
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Golovin RM, Broadie K. Developmental experience-dependent plasticity in the first synapse of the Drosophila olfactory circuit. J Neurophysiol 2016; 116:2730-2738. [PMID: 27683892 DOI: 10.1152/jn.00616.2016] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 09/26/2016] [Indexed: 12/15/2022] Open
Abstract
Evidence accumulating over the past 15 years soundly refutes the dogma that the Drosophila nervous system is hardwired. The preponderance of studies reveals activity-dependent neural circuit refinement driving optimization of behavioral outputs. We describe developmental, sensory input-dependent plasticity in the brain olfactory antennal lobe, which we term long-term central adaption (LTCA). LTCA is evoked by prolonged exposure to an odorant during the first week of posteclosion life, resulting in a persistently decreased response to aversive odors and an enhanced response to attractive odors. This limited window of early-use, experience-dependent plasticity represents a critical period of olfactory circuit refinement tuned by initial sensory input. Consequent behavioral adaptations have been associated with changes in the output of olfactory projection neurons to higher brain centers. Recent studies have indicated a central role for local interneuron signaling in LTCA presentation. Genetic and molecular analyses have implicated the mRNA-binding fragile X mental retardation protein and ataxin-2 regulators, Notch trans-synaptic signaling, and cAMP signal transduction as core regulatory steps driving LTCA. In this article, we discuss the structural, functional, and behavioral changes associated with LTCA and review our current understanding of the molecular pathways underlying these developmental, experience-dependent changes in the olfactory circuitry.
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Affiliation(s)
- Randall M Golovin
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennessee; and
| | - Kendal Broadie
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennessee; and .,Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee
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211
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Gupta VK, Pech U, Bhukel A, Fulterer A, Ender A, Mauermann SF, Andlauer TFM, Antwi-Adjei E, Beuschel C, Thriene K, Maglione M, Quentin C, Bushow R, Schwärzel M, Mielke T, Madeo F, Dengjel J, Fiala A, Sigrist SJ. Spermidine Suppresses Age-Associated Memory Impairment by Preventing Adverse Increase of Presynaptic Active Zone Size and Release. PLoS Biol 2016; 14:e1002563. [PMID: 27684064 PMCID: PMC5042543 DOI: 10.1371/journal.pbio.1002563] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2016] [Accepted: 08/26/2016] [Indexed: 01/24/2023] Open
Abstract
Memories are assumed to be formed by sets of synapses changing their structural or functional performance. The efficacy of forming new memories declines with advancing age, but the synaptic changes underlying age-induced memory impairment remain poorly understood. Recently, we found spermidine feeding to specifically suppress age-dependent impairments in forming olfactory memories, providing a mean to search for synaptic changes involved in age-dependent memory impairment. Here, we show that a specific synaptic compartment, the presynaptic active zone (AZ), increases the size of its ultrastructural elaboration and releases significantly more synaptic vesicles with advancing age. These age-induced AZ changes, however, were fully suppressed by spermidine feeding. A genetically enforced enlargement of AZ scaffolds (four gene-copies of BRP) impaired memory formation in young animals. Thus, in the Drosophila nervous system, aging AZs seem to steer towards the upper limit of their operational range, limiting synaptic plasticity and contributing to impairment of memory formation. Spermidine feeding suppresses age-dependent memory impairment by counteracting these age-dependent changes directly at the synapse.
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Affiliation(s)
- Varun K. Gupta
- Institute for Biology/Genetics, Freie Universität Berlin, Berlin, Germany
- NeuroCure, Charité, Berlin, Germany
| | - Ulrike Pech
- Georg-August-Universität Göttingen, Molecular Neurobiology of Behavior, Göttingen, Germany
| | - Anuradha Bhukel
- Institute for Biology/Genetics, Freie Universität Berlin, Berlin, Germany
- NeuroCure, Charité, Berlin, Germany
| | - Andreas Fulterer
- Institute for Biology/Genetics, Freie Universität Berlin, Berlin, Germany
- NeuroCure, Charité, Berlin, Germany
| | - Anatoli Ender
- Institute for Biology/Genetics, Freie Universität Berlin, Berlin, Germany
| | - Stephan F. Mauermann
- Institute for Biology/Genetics, Freie Universität Berlin, Berlin, Germany
- NeuroCure, Charité, Berlin, Germany
| | | | | | - Christine Beuschel
- Institute for Biology/Genetics, Freie Universität Berlin, Berlin, Germany
| | - Kerstin Thriene
- Centre for Systems Biological Analysis, University of Freiburg, Freiburg, Germany
| | - Marta Maglione
- Institute for Biology/Genetics, Freie Universität Berlin, Berlin, Germany
- NeuroCure, Charité, Berlin, Germany
| | - Christine Quentin
- Institute for Biology/Genetics, Freie Universität Berlin, Berlin, Germany
- NeuroCure, Charité, Berlin, Germany
| | - René Bushow
- Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Martin Schwärzel
- Institute for Biology/Genetics, Freie Universität Berlin, Berlin, Germany
| | - Thorsten Mielke
- Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Frank Madeo
- Institute for Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria
- BioTechMed Graz, Graz, Austria
| | - Joern Dengjel
- Centre for Systems Biological Analysis, University of Freiburg, Freiburg, Germany
| | - André Fiala
- Georg-August-Universität Göttingen, Molecular Neurobiology of Behavior, Göttingen, Germany
| | - Stephan J. Sigrist
- Institute for Biology/Genetics, Freie Universität Berlin, Berlin, Germany
- NeuroCure, Charité, Berlin, Germany
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212
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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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213
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Sachse S, Beshel J. The good, the bad, and the hungry: how the central brain codes odor valence to facilitate food approach in Drosophila. Curr Opin Neurobiol 2016; 40:53-58. [PMID: 27393869 DOI: 10.1016/j.conb.2016.06.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 05/19/2016] [Accepted: 06/22/2016] [Indexed: 01/25/2023]
Abstract
All animals must eat in order to survive but first they must successfully locate and appraise food resources in a manner consonant with their needs. To accomplish this, external sensory information, in particular olfactory food cues, need to be detected and appropriately categorized. Recent advances in Drosophila point to the existence of parallel processing circuits within the central brain that encode odor valence, supporting approach and avoidance behaviors. Strikingly, many elements within these neural systems are subject to modification as a function of the fly's satiety state. In this review we describe those advances and their potential impact on the decision to feed.
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Affiliation(s)
- Silke Sachse
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Jennifer Beshel
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, United States.
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214
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Poo MM, Pignatelli M, Ryan TJ, Tonegawa S, Bonhoeffer T, Martin KC, Rudenko A, Tsai LH, Tsien RW, Fishell G, Mullins C, Gonçalves JT, Shtrahman M, Johnston ST, Gage FH, Dan Y, Long J, Buzsáki G, Stevens C. What is memory? The present state of the engram. BMC Biol 2016; 14:40. [PMID: 27197636 PMCID: PMC4874022 DOI: 10.1186/s12915-016-0261-6] [Citation(s) in RCA: 204] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The mechanism of memory remains one of the great unsolved problems of biology. Grappling with the question more than a hundred years ago, the German zoologist Richard Semon formulated the concept of the engram, lasting connections in the brain that result from simultaneous “excitations”, whose precise physical nature and consequences were out of reach of the biology of his day. Neuroscientists now have the knowledge and tools to tackle this question, however, and this Forum brings together leading contemporary views on the mechanisms of memory and what the engram means today.
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Affiliation(s)
- Mu-Ming Poo
- Institute of Neuroscience, Chinese Academy of Sciences, Shanghai, China.
| | - Michele Pignatelli
- RIKEN-MIT Center for Neural Circuit Genetics at the Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Tomás J Ryan
- RIKEN-MIT Center for Neural Circuit Genetics at the Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.,Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Susumu Tonegawa
- RIKEN-MIT Center for Neural Circuit Genetics at the Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.,Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | | | - Kelsey C Martin
- Department of Biological Chemistry and Department of Psychiatry and Biobehavioral Studies, David Geffen School of Medicine, BSRB 390B, 615 Charles E. Young Dr. South, University of California, Los Angeles, CA, 90095, USA
| | - Andrii Rudenko
- Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Li-Huei Tsai
- Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Richard W Tsien
- The Neuroscience Institute, School of Medicine and Center for Neural Science, New York University, New York, NY, 10016, USA
| | - Gord Fishell
- The Neuroscience Institute, School of Medicine and Center for Neural Science, New York University, New York, NY, 10016, USA
| | - Caitlin Mullins
- The Neuroscience Institute, School of Medicine and Center for Neural Science, New York University, New York, NY, 10016, USA
| | - J Tiago Gonçalves
- Salk Institute for Biological Studies, Laboratory of Genetics, 10010 N. Torrey Pines Road, La Jolla, CA, 92037, USA
| | - Matthew Shtrahman
- Salk Institute for Biological Studies, Laboratory of Genetics, 10010 N. Torrey Pines Road, La Jolla, CA, 92037, USA
| | - Stephen T Johnston
- Salk Institute for Biological Studies, Laboratory of Genetics, 10010 N. Torrey Pines Road, La Jolla, CA, 92037, USA
| | - Fred H Gage
- Salk Institute for Biological Studies, Laboratory of Genetics, 10010 N. Torrey Pines Road, La Jolla, CA, 92037, USA
| | - Yang Dan
- HHMI, Department of Molecular and Cell Biology, University of California, Berkeley, USA
| | - John Long
- The Neuroscience Institute, School of Medicine and Center for Neural Science, New York University, New York, NY, 10016, USA
| | - György Buzsáki
- The Neuroscience Institute, School of Medicine and Center for Neural Science, New York University, New York, NY, 10016, USA
| | - Charles Stevens
- Salk Institute for Biological Studies, Laboratory of Genetics, 10010 N. Torrey Pines Road, La Jolla, CA, 92037, USA
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215
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Perisse E, Owald D, Barnstedt O, Talbot CB, Huetteroth W, Waddell S. Aversive Learning and Appetitive Motivation Toggle Feed-Forward Inhibition in the Drosophila Mushroom Body. Neuron 2016; 90:1086-99. [PMID: 27210550 PMCID: PMC4893166 DOI: 10.1016/j.neuron.2016.04.034] [Citation(s) in RCA: 136] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 03/27/2016] [Accepted: 04/19/2016] [Indexed: 11/23/2022]
Abstract
In Drosophila, negatively reinforcing dopaminergic neurons also provide the inhibitory control of satiety over appetitive memory expression. Here we show that aversive learning causes a persistent depression of the conditioned odor drive to two downstream feed-forward inhibitory GABAergic interneurons of the mushroom body, called MVP2, or mushroom body output neuron (MBON)-γ1pedc>α/β. However, MVP2 neuron output is only essential for expression of short-term aversive memory. Stimulating MVP2 neurons preferentially inhibits the odor-evoked activity of avoidance-directing MBONs and odor-driven avoidance behavior, whereas their inhibition enhances odor avoidance. In contrast, odor-evoked activity of MVP2 neurons is elevated in hungry flies, and their feed-forward inhibition is required for expression of appetitive memory at all times. Moreover, imposing MVP2 activity promotes inappropriate appetitive memory expression in food-satiated flies. Aversive learning and appetitive motivation therefore toggle alternate modes of a common feed-forward inhibitory MVP2 pathway to promote conditioned odor avoidance or approach. Aversive learning reduces odor-specific feed-forward inhibition in mushroom body Feed-forward inhibition selectively inhibits avoidance-directing neural pathways Appetitive motivation increases feed-forward inhibition in the mushroom body Imposing feed-forward inhibition favors appetitive memory expression
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Affiliation(s)
- Emmanuel Perisse
- Centre for Neural Circuits and Behaviour, The University of Oxford, Tinsley Building, Mansfield Road, Oxford, OX1 3SR, UK
| | - David Owald
- Centre for Neural Circuits and Behaviour, The University of Oxford, Tinsley Building, Mansfield Road, Oxford, OX1 3SR, UK
| | - Oliver Barnstedt
- Centre for Neural Circuits and Behaviour, The University of Oxford, Tinsley Building, Mansfield Road, Oxford, OX1 3SR, UK
| | - Clifford B Talbot
- Centre for Neural Circuits and Behaviour, The University of Oxford, Tinsley Building, Mansfield Road, Oxford, OX1 3SR, UK
| | - Wolf Huetteroth
- Centre for Neural Circuits and Behaviour, The University of Oxford, Tinsley Building, Mansfield Road, Oxford, OX1 3SR, UK
| | - Scott Waddell
- Centre for Neural Circuits and Behaviour, The University of Oxford, Tinsley Building, Mansfield Road, Oxford, OX1 3SR, UK.
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216
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Crocker A, Guan XJ, Murphy CT, Murthy M. Cell-Type-Specific Transcriptome Analysis in the Drosophila Mushroom Body Reveals Memory-Related Changes in Gene Expression. Cell Rep 2016; 15:1580-1596. [PMID: 27160913 DOI: 10.1016/j.celrep.2016.04.046] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Revised: 02/21/2016] [Accepted: 04/08/2016] [Indexed: 12/25/2022] Open
Abstract
Learning and memory formation in Drosophila rely on a network of neurons in the mushroom bodies (MBs). Whereas numerous studies have delineated roles for individual cell types within this network in aspects of learning or memory, whether or not these cells can also be distinguished by the genes they express remains unresolved. In addition, the changes in gene expression that accompany long-term memory formation within the MBs have not yet been studied by neuron type. Here, we address both issues by performing RNA sequencing on single cell types (harvested via patch pipets) within the MB. We discover that the expression of genes that encode cell surface receptors is sufficient to identify cell types and that a subset of these genes, required for sensory transduction in peripheral sensory neurons, is not only expressed within individual neurons of the MB in the central brain, but is also critical for memory formation.
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Affiliation(s)
- Amanda Crocker
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ 08544, USA
| | - Xiao-Juan Guan
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ 08544, USA
| | - Coleen T Murphy
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA; Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA; Paul F. Glenn Laboratories for Aging Research, Princeton University, Princeton, NJ 08544, USA
| | - Mala Murthy
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ 08544, USA; Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.
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217
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Kittel RJ, Heckmann M. Synaptic Vesicle Proteins and Active Zone Plasticity. Front Synaptic Neurosci 2016; 8:8. [PMID: 27148040 PMCID: PMC4834300 DOI: 10.3389/fnsyn.2016.00008] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 03/31/2016] [Indexed: 11/13/2022] Open
Abstract
Neurotransmitter is released from synaptic vesicles at the highly specialized presynaptic active zone (AZ). The complex molecular architecture of AZs mediates the speed, precision and plasticity of synaptic transmission. Importantly, structural and functional properties of AZs vary significantly, even for a given connection. Thus, there appear to be distinct AZ states, which fundamentally influence neuronal communication by controlling the positioning and release of synaptic vesicles. Vice versa, recent evidence has revealed that synaptic vesicle components also modulate organizational states of the AZ. The protein-rich cytomatrix at the active zone (CAZ) provides a structural platform for molecular interactions guiding vesicle exocytosis. Studies in Drosophila have now demonstrated that the vesicle proteins Synaptotagmin-1 (Syt1) and Rab3 also regulate glutamate release by shaping differentiation of the CAZ ultrastructure. We review these unexpected findings and discuss mechanistic interpretations of the reciprocal relationship between synaptic vesicles and AZ states, which has heretofore received little attention.
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Affiliation(s)
- Robert J Kittel
- Department of Neurophysiology, Institute of Physiology, Julius-Maximilians-University Würzburg Würzburg, Germany
| | - Manfred Heckmann
- Department of Neurophysiology, Institute of Physiology, Julius-Maximilians-University Würzburg Würzburg, Germany
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218
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Vogt K, Aso Y, Hige T, Knapek S, Ichinose T, Friedrich AB, Turner GC, Rubin GM, Tanimoto H. Direct neural pathways convey distinct visual information to Drosophila mushroom bodies. eLife 2016; 5. [PMID: 27083044 PMCID: PMC4884080 DOI: 10.7554/elife.14009] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Accepted: 04/14/2016] [Indexed: 01/02/2023] Open
Abstract
Previously, we demonstrated that visual and olfactory associative memories of Drosophila share mushroom body (MB) circuits (Vogt et al., 2014). Unlike for odor representation, the MB circuit for visual information has not been characterized. Here, we show that a small subset of MB Kenyon cells (KCs) selectively responds to visual but not olfactory stimulation. The dendrites of these atypical KCs form a ventral accessory calyx (vAC), distinct from the main calyx that receives olfactory input. We identified two types of visual projection neurons (VPNs) directly connecting the optic lobes and the vAC. Strikingly, these VPNs are differentially required for visual memories of color and brightness. The segregation of visual and olfactory domains in the MB allows independent processing of distinct sensory memories and may be a conserved form of sensory representations among insects. DOI:http://dx.doi.org/10.7554/eLife.14009.001
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Affiliation(s)
- Katrin Vogt
- Max-Planck Institut für Neurobiologie, Martinsried, Germany.,Tohoku University Graduate School of Life Sciences, Sendai, Japan
| | - Yoshinori Aso
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Toshihide Hige
- Cold Spring Harbor Laboratory, Cold Spring Harbor, United States
| | - Stephan Knapek
- Max-Planck Institut für Neurobiologie, Martinsried, Germany
| | - Toshiharu Ichinose
- Max-Planck Institut für Neurobiologie, Martinsried, Germany.,Tohoku University Graduate School of Life Sciences, Sendai, Japan
| | | | - Glenn C Turner
- Cold Spring Harbor Laboratory, Cold Spring Harbor, United States
| | - Gerald M Rubin
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Hiromu Tanimoto
- Max-Planck Institut für Neurobiologie, Martinsried, Germany.,Tohoku University Graduate School of Life Sciences, Sendai, Japan
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219
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Barnstedt O, Owald D, Felsenberg J, Brain R, Moszynski JP, Talbot CB, Perrat PN, Waddell S. Memory-Relevant Mushroom Body Output Synapses Are Cholinergic. Neuron 2016; 89:1237-1247. [PMID: 26948892 PMCID: PMC4819445 DOI: 10.1016/j.neuron.2016.02.015] [Citation(s) in RCA: 119] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Revised: 01/04/2016] [Accepted: 01/27/2016] [Indexed: 11/17/2022]
Abstract
Memories are stored in the fan-out fan-in neural architectures of the mammalian cerebellum and hippocampus and the insect mushroom bodies. However, whereas key plasticity occurs at glutamatergic synapses in mammals, the neurochemistry of the memory-storing mushroom body Kenyon cell output synapses is unknown. Here we demonstrate a role for acetylcholine (ACh) in Drosophila. Kenyon cells express the ACh-processing proteins ChAT and VAChT, and reducing their expression impairs learned olfactory-driven behavior. Local ACh application, or direct Kenyon cell activation, evokes activity in mushroom body output neurons (MBONs). MBON activation depends on VAChT expression in Kenyon cells and is blocked by ACh receptor antagonism. Furthermore, reducing nicotinic ACh receptor subunit expression in MBONs compromises odor-evoked activation and redirects odor-driven behavior. Lastly, peptidergic corelease enhances ACh-evoked responses in MBONs, suggesting an interaction between the fast- and slow-acting transmitters. Therefore, olfactory memories in Drosophila are likely stored as plasticity of cholinergic synapses. Mushroom body Kenyon cell function requires ChAT and VAChT expression Kenyon cell-released acetylcholine drives mushroom body output neurons Blocking nicotinic receptors impairs mushroom body output neuron activation Acetylcholine interacts with coreleased neuropeptide
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Affiliation(s)
- Oliver Barnstedt
- Centre for Neural Circuits and Behaviour, The University of Oxford, Tinsley Building, Mansfield Road, Oxford OX1 3SR, UK
| | - David Owald
- Centre for Neural Circuits and Behaviour, The University of Oxford, Tinsley Building, Mansfield Road, Oxford OX1 3SR, UK.
| | - Johannes Felsenberg
- Centre for Neural Circuits and Behaviour, The University of Oxford, Tinsley Building, Mansfield Road, Oxford OX1 3SR, UK
| | - Ruth Brain
- Centre for Neural Circuits and Behaviour, The University of Oxford, Tinsley Building, Mansfield Road, Oxford OX1 3SR, UK
| | - John-Paul Moszynski
- Centre for Neural Circuits and Behaviour, The University of Oxford, Tinsley Building, Mansfield Road, Oxford OX1 3SR, UK
| | - Clifford B Talbot
- Centre for Neural Circuits and Behaviour, The University of Oxford, Tinsley Building, Mansfield Road, Oxford OX1 3SR, UK
| | - Paola N Perrat
- Department of Neurobiology, UMass Medical School, Worcester, MA 01605, USA
| | - Scott Waddell
- Centre for Neural Circuits and Behaviour, The University of Oxford, Tinsley Building, Mansfield Road, Oxford OX1 3SR, UK.
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220
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221
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Haberkern H, Jayaraman V. Studying small brains to understand the building blocks of cognition. Curr Opin Neurobiol 2016; 37:59-65. [PMID: 26826948 DOI: 10.1016/j.conb.2016.01.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 01/12/2016] [Indexed: 01/09/2023]
Abstract
Cognition encompasses a range of higher-order mental processes, such as attention, working memory, and model-based decision-making. These processes are thought to involve the dynamic interaction of multiple central brain regions. A mechanistic understanding of such computations requires not only monitoring and manipulating specific neural populations during behavior, but also knowing the connectivity of the underlying circuitry. These goals are experimentally challenging in mammals, but are feasible in numerically simpler insect brains. In Drosophila melanogaster in particular, genetic tools enable precisely targeted physiology and optogenetics in actively behaving animals. In this article we discuss how these advantages are increasingly being leveraged to study abstract neural representations and sensorimotor computations that may be relevant for cognition in both insects and mammals.
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Affiliation(s)
- Hannah Haberkern
- Janelia Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - Vivek Jayaraman
- Janelia Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, VA 20147, USA.
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