101
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Elkahlah NA, Rogow JA, Ahmed M, Clowney EJ. Presynaptic developmental plasticity allows robust sparse wiring of the Drosophila mushroom body. eLife 2020; 9:e52278. [PMID: 31913123 PMCID: PMC7028369 DOI: 10.7554/elife.52278] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2019] [Accepted: 01/07/2020] [Indexed: 01/29/2023] Open
Abstract
In order to represent complex stimuli, principle neurons of associative learning regions receive combinatorial sensory inputs. Density of combinatorial innervation is theorized to determine the number of distinct stimuli that can be represented and distinguished from one another, with sparse innervation thought to optimize the complexity of representations in networks of limited size. How the convergence of combinatorial inputs to principle neurons of associative brain regions is established during development is unknown. Here, we explore the developmental patterning of sparse olfactory inputs to Kenyon cells of the Drosophila melanogaster mushroom body. By manipulating the ratio between pre- and post-synaptic cells, we find that postsynaptic Kenyon cells set convergence ratio: Kenyon cells produce fixed distributions of dendritic claws while presynaptic processes are plastic. Moreover, we show that sparse odor responses are preserved in mushroom bodies with reduced cellular repertoires, suggesting that developmental specification of convergence ratio allows functional robustness.
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Affiliation(s)
- Najia A Elkahlah
- Department of Molecular, Cellular and Developmental BiologyThe University of MichiganAnn ArborUnited States
| | - Jackson A Rogow
- Laboratory of Neurophysiology and BehaviorThe Rockefeller UniversityNew YorkUnited States
| | - Maria Ahmed
- Department of Molecular, Cellular and Developmental BiologyThe University of MichiganAnn ArborUnited States
| | - E Josephine Clowney
- Department of Molecular, Cellular and Developmental BiologyThe University of MichiganAnn ArborUnited States
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102
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Affiliation(s)
- Nadine Ehmann
- Department of Animal Physiology, Institute of Biology, Leipzig University, Leipzig, Germany
| | - Dennis Pauls
- Department of Animal Physiology, Institute of Biology, Leipzig University, Leipzig, Germany
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103
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Amin H, Lin AC. Neuronal mechanisms underlying innate and learned olfactory processing in Drosophila. CURRENT OPINION IN INSECT SCIENCE 2019; 36:9-17. [PMID: 31280185 DOI: 10.1016/j.cois.2019.06.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Accepted: 06/03/2019] [Indexed: 06/09/2023]
Abstract
Olfaction allows animals to adapt their behavior in response to different chemical cues in their environment. How does the brain efficiently discriminate different odors to drive appropriate behavior, and how does it flexibly assign value to odors to adjust behavior according to experience? This review traces neuronal mechanisms underlying these processes in adult Drosophila melanogaster from olfactory receptors to higher brain centers. We highlight neural circuit principles such as lateral inhibition, segregation and integration of olfactory channels, temporal accumulation of sensory evidence, and compartmentalized synaptic plasticity underlying associative memory.
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Affiliation(s)
- Hoger Amin
- Department of Biomedical Science, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, United Kingdom
| | - Andrew C Lin
- Department of Biomedical Science, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, United Kingdom.
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104
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Qin S, Li Q, Tang C, Tu Y. Optimal compressed sensing strategies for an array of nonlinear olfactory receptor neurons with and without spontaneous activity. Proc Natl Acad Sci U S A 2019; 116:20286-20295. [PMID: 31548382 PMCID: PMC6789560 DOI: 10.1073/pnas.1906571116] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
There are numerous different odorant molecules in nature but only a relatively small number of olfactory receptor neurons (ORNs) in brains. This "compressed sensing" challenge is compounded by the constraint that ORNs are nonlinear sensors with a finite dynamic range. Here, we investigate possible optimal olfactory coding strategies by maximizing mutual information between odor mixtures and ORNs' responses with respect to the bipartite odor-receptor interaction network (ORIN) characterized by sensitivities between all odorant-ORN pairs. For ORNs without spontaneous (basal) activity, we find that the optimal ORIN is sparse-a finite fraction of sensitives are zero, and the nonzero sensitivities follow a broad distribution that depends on the odor statistics. We show analytically that sparsity in the optimal ORIN originates from a trade-off between the broad tuning of ORNs and possible interference. Furthermore, we show that the optimal ORIN enhances performances of downstream learning tasks (reconstruction and classification). For ORNs with a finite basal activity, we find that having inhibitory odor-receptor interactions increases the coding capacity and the fraction of inhibitory interactions increases with the ORN basal activity. We argue that basal activities in sensory receptors in different organisms are due to the trade-off between the increase in coding capacity and the cost of maintaining the spontaneous basal activity. Our theoretical findings are consistent with existing experiments and predictions are made to further test our theory. The optimal coding model provides a unifying framework to understand the peripheral olfactory systems across different organisms.
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Affiliation(s)
- Shanshan Qin
- Center for Quantitative Biology, Peking University, Beijing 100871, China
| | - Qianyi Li
- Integrated Science Program, Yuanpei College, Peking University, Beijing 100871, China
| | - Chao Tang
- Center for Quantitative Biology, Peking University, Beijing 100871, China;
- School of Physics, Peking University, Beijing 100871, China
- Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Yuhai Tu
- Physical Sciences Department, IBM T. J. Watson Research Center, Yorktown Heights, NY 10598
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105
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Separate But Interactive Parallel Olfactory Processing Streams Governed by Different Types of GABAergic Feedback Neurons in the Mushroom Body of a Basal Insect. J Neurosci 2019; 39:8690-8704. [PMID: 31548236 DOI: 10.1523/jneurosci.0088-19.2019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 09/08/2019] [Accepted: 09/17/2019] [Indexed: 11/21/2022] Open
Abstract
The basic organization of the olfactory system has been the subject of extensive studies in vertebrates and invertebrates. In many animals, GABA-ergic neurons inhibit spike activities of higher-order olfactory neurons and help sparsening of their odor representations. In the cockroach, two different types of GABA-immunoreactive interneurons (calyceal giants [CGs]) mainly project to the base and lip regions of the calyces (input areas) of the mushroom body (MB), a second-order olfactory center. The base and lip regions receive axon terminals of two different types of projection neurons, which receive synapses from different classes of olfactory sensory neurons (OSNs), and receive dendrites of different classes of Kenyon cells, MB intrinsic neurons. We performed intracellular recordings from pairs of CGs and MB output neurons (MBONs) of male American cockroaches, the latter receiving synapses from Kenyon cells, and we found that a CG receives excitatory synapses from an MBON and that odor responses of the MBON are changed by current injection into the CG. Such feedback effects, however, were often weak or absent in pairs of neurons that belong to different streams, suggesting parallel organization of the recurrent pathways, although interactions between different streams were also evident. Cross-covariance analysis of the spike activities of CGs and MBONs suggested that odor stimulation produces synchronized spike activities in MBONs and then in CGs. We suggest that there are separate but interactive parallel streams to process odors detected by different OSNs throughout the olfactory processing system in cockroaches.SIGNIFICANCE STATEMENT Organizational principles of the olfactory system have been the subject of extensive studies. In cockroaches, signals from olfactory sensory neurons (OSNs) in two different classes of sensilla are sent to two different classes of projection neurons, which terminate in different areas of the mushroom body (MB), each area having dendrites of different classes of MB intrinsic neurons (Kenyon cells) and terminations of different classes of GABAergic neurons. Physiological and morphological assessments derived from simultaneous intracellular recordings/stainings from GABAergic neurons and MB output neurons suggested that GABAergic neurons play feedback roles and that odors detected by OSNs are processed in separate but interactive processing streams throughout the central olfactory system.
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106
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Bielopolski N, Amin H, Apostolopoulou AA, Rozenfeld E, Lerner H, Huetteroth W, Lin AC, Parnas M. Inhibitory muscarinic acetylcholine receptors enhance aversive olfactory learning in adult Drosophila. eLife 2019; 8:48264. [PMID: 31215865 PMCID: PMC6641838 DOI: 10.7554/elife.48264] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 06/18/2019] [Indexed: 11/13/2022] Open
Abstract
Olfactory associative learning in Drosophila is mediated by synaptic plasticity between the Kenyon cells of the mushroom body and their output neurons. Both Kenyon cells and their inputs from projection neurons are cholinergic, yet little is known about the physiological function of muscarinic acetylcholine receptors in learning in adult flies. Here, we show that aversive olfactory learning in adult flies requires type A muscarinic acetylcholine receptors (mAChR-A), particularly in the gamma subtype of Kenyon cells. mAChR-A inhibits odor responses and is localized in Kenyon cell dendrites. Moreover, mAChR-A knockdown impairs the learning-associated depression of odor responses in a mushroom body output neuron. Our results suggest that mAChR-A function in Kenyon cell dendrites is required for synaptic plasticity between Kenyon cells and their output neurons.
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Affiliation(s)
- Noa Bielopolski
- Department of Physiology and Pharmacology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Hoger Amin
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | | | - Eyal Rozenfeld
- Department of Physiology and Pharmacology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Hadas Lerner
- Department of Physiology and Pharmacology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Wolf Huetteroth
- Institute for Biology, University of Leipzig, Leipzig, Germany
| | - Andrew C Lin
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | - Moshe Parnas
- Department of Physiology and Pharmacology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.,Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
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107
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Yamazaki D, Hiroi M, Abe T, Shimizu K, Minami-Ohtsubo M, Maeyama Y, Horiuchi J, Tabata T. Two Parallel Pathways Assign Opposing Odor Valences during Drosophila Memory Formation. Cell Rep 2019; 22:2346-2358. [PMID: 29490271 DOI: 10.1016/j.celrep.2018.02.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 12/13/2017] [Accepted: 02/01/2018] [Indexed: 11/15/2022] Open
Abstract
During olfactory associative learning in Drosophila, odors activate specific subsets of intrinsic mushroom body (MB) neurons. Coincident exposure to either rewards or punishments is thought to activate extrinsic dopaminergic neurons, which modulate synaptic connections between odor-encoding MB neurons and MB output neurons to alter behaviors. However, here we identify two classes of intrinsic MB γ neurons based on cAMP response element (CRE)-dependent expression, γCRE-p and γCRE-n, which encode aversive and appetitive valences. γCRE-p and γCRE-n neurons act antagonistically to maintain neutral valences for neutral odors. Activation or inhibition of either cell type upsets this balance, toggling odor preferences to either positive or negative values. The mushroom body output neurons, MBON-γ5β'2a/β'2mp and MBON-γ2α'1, mediate the actions of γCRE-p and γCRE-n neurons. Our data indicate that MB neurons encode valence information, as well as odor information, and this information is integrated through a process involving MBONs to regulate learning and memory.
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Affiliation(s)
- Daisuke Yamazaki
- Institute of Molecular and Cellular Biosciences, University of Tokyo, Yayoi 1-1-1, Tokyo 113-0032, Japan.
| | - Makoto Hiroi
- Institute of Molecular and Cellular Biosciences, University of Tokyo, Yayoi 1-1-1, Tokyo 113-0032, Japan
| | - Takashi Abe
- Institute of Molecular and Cellular Biosciences, University of Tokyo, Yayoi 1-1-1, Tokyo 113-0032, Japan
| | - Kazumichi Shimizu
- Institute of Molecular and Cellular Biosciences, University of Tokyo, Yayoi 1-1-1, Tokyo 113-0032, Japan
| | - Maki Minami-Ohtsubo
- Institute of Molecular and Cellular Biosciences, University of Tokyo, Yayoi 1-1-1, Tokyo 113-0032, Japan
| | - Yuko Maeyama
- Institute of Molecular and Cellular Biosciences, University of Tokyo, Yayoi 1-1-1, Tokyo 113-0032, Japan
| | - Junjiro Horiuchi
- Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya, Tokyo, Japan
| | - Tetsuya Tabata
- Institute of Molecular and Cellular Biosciences, University of Tokyo, Yayoi 1-1-1, Tokyo 113-0032, Japan.
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108
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Dolan MJ, Frechter S, Bates AS, Dan C, Huoviala P, Roberts RJV, Schlegel P, Dhawan S, Tabano R, Dionne H, Christoforou C, Close K, Sutcliffe B, Giuliani B, Li F, Costa M, Ihrke G, Meissner GW, Bock DD, Aso Y, Rubin GM, Jefferis GSXE. Neurogenetic dissection of the Drosophila lateral horn reveals major outputs, diverse behavioural functions, and interactions with the mushroom body. eLife 2019; 8:e43079. [PMID: 31112130 PMCID: PMC6529221 DOI: 10.7554/elife.43079] [Citation(s) in RCA: 84] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 02/07/2019] [Indexed: 01/26/2023] Open
Abstract
Animals exhibit innate behaviours to a variety of sensory stimuli including olfactory cues. In Drosophila, one higher olfactory centre, the lateral horn (LH), is implicated in innate behaviour. However, our structural and functional understanding of the LH is scant, in large part due to a lack of sparse neurogenetic tools for this region. We generate a collection of split-GAL4 driver lines providing genetic access to 82 LH cell types. We use these to create an anatomical and neurotransmitter map of the LH and link this to EM connectomics data. We find ~30% of LH projections converge with outputs from the mushroom body, site of olfactory learning and memory. Using optogenetic activation, we identify LH cell types that drive changes in valence behavior or specific locomotor programs. In summary, we have generated a resource for manipulating and mapping LH neurons, providing new insights into the circuit basis of innate and learned olfactory behavior.
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Affiliation(s)
- Michael-John Dolan
- Howard Hughes Medical Institute, Janelia Research CampusAshburnUnited States
- Division of NeurobiologyMRC Laboratory of Molecular BiologyCambridgeUnited Kingdom
| | - Shahar Frechter
- Division of NeurobiologyMRC Laboratory of Molecular BiologyCambridgeUnited Kingdom
| | | | - Chuntao Dan
- Howard Hughes Medical Institute, Janelia Research CampusAshburnUnited States
| | - Paavo Huoviala
- Division of NeurobiologyMRC Laboratory of Molecular BiologyCambridgeUnited Kingdom
| | | | - Philipp Schlegel
- Division of NeurobiologyMRC Laboratory of Molecular BiologyCambridgeUnited Kingdom
- Department of ZoologyUniversity of CambridgeCambridgeUnited Kingdom
| | - Serene Dhawan
- Division of NeurobiologyMRC Laboratory of Molecular BiologyCambridgeUnited Kingdom
- Department of ZoologyUniversity of CambridgeCambridgeUnited Kingdom
| | - Remy Tabano
- Howard Hughes Medical Institute, Janelia Research CampusAshburnUnited States
| | - Heather Dionne
- Howard Hughes Medical Institute, Janelia Research CampusAshburnUnited States
| | | | - Kari Close
- Howard Hughes Medical Institute, Janelia Research CampusAshburnUnited States
| | - Ben Sutcliffe
- Division of NeurobiologyMRC Laboratory of Molecular BiologyCambridgeUnited Kingdom
| | - Bianca Giuliani
- Howard Hughes Medical Institute, Janelia Research CampusAshburnUnited States
| | - Feng Li
- Howard Hughes Medical Institute, Janelia Research CampusAshburnUnited States
| | - Marta Costa
- Department of ZoologyUniversity of CambridgeCambridgeUnited Kingdom
| | - Gudrun Ihrke
- Howard Hughes Medical Institute, Janelia Research CampusAshburnUnited States
| | | | - Davi D Bock
- Howard Hughes Medical Institute, Janelia Research CampusAshburnUnited States
| | - Yoshinori Aso
- Howard Hughes Medical Institute, Janelia Research CampusAshburnUnited States
| | - Gerald M Rubin
- Howard Hughes Medical Institute, Janelia Research CampusAshburnUnited States
| | - Gregory SXE Jefferis
- Howard Hughes Medical Institute, Janelia Research CampusAshburnUnited States
- Division of NeurobiologyMRC Laboratory of Molecular BiologyCambridgeUnited Kingdom
- Department of ZoologyUniversity of CambridgeCambridgeUnited Kingdom
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109
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Gu S, Wang F, Patel NP, Bourgeois JA, Huang JH. A Model for Basic Emotions Using Observations of Behavior in Drosophila. Front Psychol 2019; 10:781. [PMID: 31068849 PMCID: PMC6491740 DOI: 10.3389/fpsyg.2019.00781] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2018] [Accepted: 03/21/2019] [Indexed: 01/21/2023] Open
Abstract
Emotion plays a crucial role, both in general human experience and in psychiatric illnesses. Despite the importance of emotion, the relative lack of objective methodologies to scientifically studying emotional phenomena limits our current understanding and thereby calls for the development of novel methodologies, such us the study of illustrative animal models. Analysis of Drosophila and other insects has unlocked new opportunities to elucidate the behavioral phenotypes of fundamentally emotional phenomena. Here we propose an integrative model of basic emotions based on observations of this animal model. The basic emotions are internal states that are modulated by neuromodulators, and these internal states are externally expressed as certain stereotypical behaviors, such as instinct, which is proposed as ancient mechanisms of survival. There are four kinds of basic emotions: happiness, sadness, fear, and anger, which are differentially associated with three core affects: reward (happiness), punishment (sadness), and stress (fear and anger). These core affects are analogous to the three primary colors (red, yellow, and blue) in that they are combined in various proportions to result in more complex “higher order” emotions, such as love and aesthetic emotion. We refer to our proposed model of emotions as called the “Three Primary Color Model of Basic Emotions.”
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Affiliation(s)
- Simeng Gu
- Institute of Brain and Psychological Science, Sichuan Normal University, Chengdu, China
| | - Fushun Wang
- Institute of Brain and Psychological Science, Sichuan Normal University, Chengdu, China.,Department of Psychology, Jiangsu University, Zhenjiang, China
| | - Nitesh P Patel
- College of Medicine, Texas A&M University, College Station, TX, United States
| | - James A Bourgeois
- College of Medicine, Texas A&M University, College Station, TX, United States.,Department of Psychiatry, Baylor Scott & White Health, Dallas, TX, United States
| | - Jason H Huang
- Department of Psychology, Jiangsu University, Zhenjiang, China.,College of Medicine, Texas A&M University, College Station, TX, United States
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110
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Horiuchi J. Recurrent loops: Incorporating prediction error and semantic/episodic theories into Drosophila associative memory models. GENES BRAIN AND BEHAVIOR 2019; 18:e12567. [PMID: 30891930 PMCID: PMC6900151 DOI: 10.1111/gbb.12567] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 02/27/2019] [Accepted: 03/16/2019] [Indexed: 12/01/2022]
Abstract
In 2003, Martin Heisenberg et al. presented a model of how associative memories could be encoded and stored in the insect brain. This model was extremely influential in the Drosophila memory field, but did not incorporate several important mammalian concepts, including ideas of separate episodic and semantic types of memory and prediction error hypotheses. In addition, at that time, the concept of memory traces recurrently entering and exiting the mushroom bodies, brain areas where associative memories are formed and stored, was unknown. In this review, I present a simple updated model incorporating these ideas, which may be useful for future studies.
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Affiliation(s)
- Junjiro Horiuchi
- Department of higher brain functions and dementias, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
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111
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Suppression of GABAergic neurons through D2-like receptor secures efficient conditioning in Drosophila aversive olfactory learning. Proc Natl Acad Sci U S A 2019; 116:5118-5125. [PMID: 30796183 DOI: 10.1073/pnas.1812342116] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The GABAergic system serves as a vital negative modulator in cognitive functions, such as learning and memory, while the mechanisms governing this inhibitory system remain to be elucidated. In Drosophila, the GABAergic anterior paired lateral (APL) neurons mediate a negative feedback essential for odor discrimination; however, their activity is suppressed by learning via unknown mechanisms. In aversive olfactory learning, a group of dopaminergic (DA) neurons is activated on electric shock (ES) and modulates the Kenyon cells (KCs) in the mushroom body, the center of olfactory learning. Here we find that the same group of DA neurons also form functional synaptic connections with the APL neurons, thereby emitting a suppressive signal to the latter through Drosophila dopamine 2-like receptor (DD2R). Knockdown of either DD2R or its downstream molecules in the APL neurons results in impaired olfactory learning at the behavioral level. Results obtained from in vivo functional imaging experiments indicate that this DD2R-dependent DA-to-APL suppression occurs during odor-ES conditioning and discharges the GABAergic inhibition on the KCs specific to the conditioned odor. Moreover, the decrease in odor response of the APL neurons persists to the postconditioning phase, and this change is also absent in DD2R knockdown flies. Taken together, our findings show that DA-to-GABA suppression is essential for restraining the GABAergic inhibition during conditioning, as well as for inducing synaptic modification in this learning circuit. Such circuit mechanisms may play conserved roles in associative learning across species.
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112
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Cayco-Gajic NA, Silver RA. Re-evaluating Circuit Mechanisms Underlying Pattern Separation. Neuron 2019; 101:584-602. [PMID: 30790539 PMCID: PMC7028396 DOI: 10.1016/j.neuron.2019.01.044] [Citation(s) in RCA: 123] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 01/07/2019] [Accepted: 01/18/2019] [Indexed: 11/22/2022]
Abstract
When animals interact with complex environments, their neural circuits must separate overlapping patterns of activity that represent sensory and motor information. Pattern separation is thought to be a key function of several brain regions, including the cerebellar cortex, insect mushroom body, and dentate gyrus. However, recent findings have questioned long-held ideas on how these circuits perform this fundamental computation. Here, we re-evaluate the functional and structural mechanisms underlying pattern separation. We argue that the dimensionality of the space available for population codes representing sensory and motor information provides a common framework for understanding pattern separation. We then discuss how these three circuits use different strategies to separate activity patterns and facilitate associative learning in the presence of trial-to-trial variability.
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Affiliation(s)
- N Alex Cayco-Gajic
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London WC1E 6BT, UK
| | - R Angus Silver
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London WC1E 6BT, UK.
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113
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Groschner LN, Miesenböck G. Mechanisms of Sensory Discrimination: Insights from Drosophila Olfaction. Annu Rev Biophys 2019; 48:209-229. [PMID: 30786228 DOI: 10.1146/annurev-biophys-052118-115655] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
All an animal can do to infer the state of its environment is to observe the sensory-evoked activity of its own neurons. These inferences about the presence, quality, or similarity of objects are probabilistic and inform behavioral decisions that are often made in close to real time. Neural systems employ several strategies to facilitate sensory discrimination: Biophysical mechanisms separate the neuronal response distributions in coding space, compress their variances, and combine information from sequential observations. We review how these strategies are implemented in the olfactory system of the fruit fly. The emerging principles of odor discrimination likely apply to other neural circuits of similar architecture.
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Affiliation(s)
- Lukas N Groschner
- Centre for Neural Circuits and Behavior, University of Oxford, Oxford OX1 3SR, United Kingdom;
| | - Gero Miesenböck
- Centre for Neural Circuits and Behavior, University of Oxford, Oxford OX1 3SR, United Kingdom;
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114
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Shih MFM, Davis FP, Henry GL, Dubnau J. Nuclear Transcriptomes of the Seven Neuronal Cell Types That Constitute the Drosophila Mushroom Bodies. G3 (BETHESDA, MD.) 2019; 9:81-94. [PMID: 30397017 PMCID: PMC6325895 DOI: 10.1534/g3.118.200726] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 11/02/2018] [Indexed: 11/18/2022]
Abstract
The insect mushroom body (MB) is a conserved brain structure that plays key roles in a diverse array of behaviors. The Drosophila melanogaster MB is the primary invertebrate model of neural circuits related to memory formation and storage, and its development, morphology, wiring, and function has been extensively studied. MBs consist of intrinsic Kenyon Cells that are divided into three major neuron classes (γ, α'/β' and α/β) and 7 cell subtypes (γd, γm, α'/β'ap, α'/β'm, α/βp, α/βs and α/βc) based on their birth order, morphology, and connectivity. These subtypes play distinct roles in memory processing, however the underlying transcriptional differences are unknown. Here, we used RNA sequencing (RNA-seq) to profile the nuclear transcriptomes of each MB neuronal cell subtypes. We identified 350 MB class- or subtype-specific genes, including the widely used α/β class marker Fas2 and the α'/β' class marker trio Immunostaining corroborates the RNA-seq measurements at the protein level for several cases. Importantly, our data provide a full accounting of the neurotransmitter receptors, transporters, neurotransmitter biosynthetic enzymes, neuropeptides, and neuropeptide receptors expressed within each of these cell types. This high-quality, cell type-level transcriptome catalog for the Drosophila MB provides a valuable resource for the fly neuroscience community.
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Affiliation(s)
| | - Fred Pejman Davis
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA; National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD
| | - Gilbert Lee Henry
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA; Cold Spring Harbor Laboratory, Cold Spring Harbor, NY
| | - Josh Dubnau
- Department of Anesthesiology, Stony Brook School of Medicine; Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, NY
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115
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Delahunt CB, Riffell JA, Kutz JN. Biological Mechanisms for Learning: A Computational Model of Olfactory Learning in the Manduca sexta Moth, With Applications to Neural Nets. Front Comput Neurosci 2018; 12:102. [PMID: 30618694 PMCID: PMC6306094 DOI: 10.3389/fncom.2018.00102] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Accepted: 12/03/2018] [Indexed: 11/23/2022] Open
Abstract
The insect olfactory system, which includes the antennal lobe (AL), mushroom body (MB), and ancillary structures, is a relatively simple neural system capable of learning. Its structural features, which are widespread in biological neural systems, process olfactory stimuli through a cascade of networks where large dimension shifts occur from stage to stage and where sparsity and randomness play a critical role in coding. Learning is partly enabled by a neuromodulatory reward mechanism of octopamine stimulation of the AL, whose increased activity induces synaptic weight updates in the MB through Hebbian plasticity. Enforced sparsity in the MB focuses Hebbian growth on neurons that are the most important for the representation of the learned odor. Based upon current biophysical knowledge, we have constructed an end-to-end computational firing-rate model of the Manduca sexta moth olfactory system which includes the interaction of the AL and MB under octopamine stimulation. Our model is able to robustly learn new odors, and neural firing rates in our simulations match the statistical features of in vivo firing rate data. From a biological perspective, the model provides a valuable tool for examining the role of neuromodulators, like octopamine, in learning, and gives insight into critical interactions between sparsity, Hebbian growth, and stimulation during learning. Our simulations also inform predictions about structural details of the olfactory system that are not currently well-characterized. From a machine learning perspective, the model yields bio-inspired mechanisms that are potentially useful in constructing neural nets for rapid learning from very few samples. These mechanisms include high-noise layers, sparse layers as noise filters, and a biologically-plausible optimization method to train the network based on octopamine stimulation, sparse layers, and Hebbian growth.
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Affiliation(s)
- Charles B. Delahunt
- Department of Electrical Engineering, University of Washington, Seattle, WA, United States
- Computational Neuroscience Center, University of Washington, Seattle, WA, United States
| | - Jeffrey A. Riffell
- Department of Biology, University of Washington, Seattle, WA, United States
| | - J. Nathan Kutz
- Department of Applied Mathematics, University of Washington, Seattle, WA, United States
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116
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The Circuit Motif as a Conceptual Tool for Multilevel Neuroscience. Trends Neurosci 2018; 41:128-136. [PMID: 29397990 DOI: 10.1016/j.tins.2018.01.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 11/07/2017] [Accepted: 01/04/2018] [Indexed: 11/24/2022]
Abstract
Modern neuroscientific techniques that specifically manipulate and measure neuronal activity in behaving animals now allow bridging of the gap from the cellular to the behavioral level. However, in doing so, they also pose new challenges. Research using incompletely defined manipulations in a high-dimensional space without clear hypotheses is likely to suffer from multiple well-known conceptual and statistical problems. In this context it is essential to develop hypotheses with testable implications across levels. Here we propose that a focus on circuit motifs can help achieve this goal. Viewing neural structures as an assembly of circuit motif building blocks is not new. However, recent tool advances have made it possible to extensively map, specifically manipulate, and quantitatively investigate circuit motifs and thereby reexamine their relevance to brain function.
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117
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Abstract
Novelty detection is a fundamental biological problem that organisms must solve to determine whether a given stimulus departs from those previously experienced. In computer science, this problem is solved efficiently using a data structure called a Bloom filter. We found that the fruit fly olfactory circuit evolved a variant of a Bloom filter to assess the novelty of odors. Compared with a traditional Bloom filter, the fly adjusts novelty responses based on two additional features: the similarity of an odor to previously experienced odors and the time elapsed since the odor was last experienced. We elaborate and validate a framework to predict novelty responses of fruit flies to given pairs of odors. We also translate insights from the fly circuit to develop a class of distance- and time-sensitive Bloom filters that outperform prior filters when evaluated on several biological and computational datasets. Overall, our work illuminates the algorithmic basis of an important neurobiological problem and offers strategies for novelty detection in computational systems.
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118
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Srinivasan S, Stevens CF. The distributed circuit within the piriform cortex makes odor discrimination robust. J Comp Neurol 2018; 526:2725-2743. [PMID: 30014545 DOI: 10.1002/cne.24492] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 05/30/2018] [Accepted: 06/01/2018] [Indexed: 12/14/2022]
Abstract
Distributed circuits wherein connections between subcircuit components seem randomly distributed are common to the olfactory circuit, hippocampus, and cerebellum. In such circuits, activation patterns seem random too, showing no detectable spatial preference, and contrast with regions that have topographic connections between subcircuits and topographic activation patterns. Quantitative studies of topographic circuits in the neocortex have yielded common principles of organization. Whether distributed circuits share similar principles of organization is unknown because similar quantitative information is missing and understanding the way they encode information remains a challenge. We addressed these needs by providing a quantitative description of the mouse piriform cortex, a paleocortical distributed circuit that subserves olfaction. The quantitative information provided two insights. First, with a nearly parameter-free model of the olfactory circuit, we show that the piriform cortex robustly maintains odor information and discrimination ability present in the olfactory bulb. Second, the paleocortex is quantitatively different from the neocortex: it has a lower surface area density, which decreases from the anterior to posterior paleocortex contrasting with the uniform neuronal density of the neocortex. These insights might also apply to other distributed circuits.
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Affiliation(s)
- Shyam Srinivasan
- Salk Institute for Biological Studies, La Jolla, California.,Kavli Institute for Brain and Mind, University of California, San Diego, California
| | - Charles F Stevens
- Salk Institute for Biological Studies, La Jolla, California.,Kavli Institute for Brain and Mind, University of California, San Diego, California
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119
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Espinoza C, Guzman SJ, Zhang X, Jonas P. Parvalbumin + interneurons obey unique connectivity rules and establish a powerful lateral-inhibition microcircuit in dentate gyrus. Nat Commun 2018; 9:4605. [PMID: 30389916 PMCID: PMC6214995 DOI: 10.1038/s41467-018-06899-3] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2018] [Accepted: 10/02/2018] [Indexed: 12/31/2022] Open
Abstract
Parvalbumin-positive (PV+) GABAergic interneurons in hippocampal microcircuits are thought to play a key role in several higher network functions, such as feedforward and feedback inhibition, network oscillations, and pattern separation. Fast lateral inhibition mediated by GABAergic interneurons may implement a winner-takes-all mechanism in the hippocampal input layer. However, it is not clear whether the functional connectivity rules of granule cells (GCs) and interneurons in the dentate gyrus are consistent with such a mechanism. Using simultaneous patch-clamp recordings from up to seven GCs and up to four PV+ interneurons in the dentate gyrus, we find that connectivity is structured in space, synapse-specific, and enriched in specific disynaptic motifs. In contrast to the neocortex, lateral inhibition in the dentate gyrus (in which a GC inhibits neighboring GCs via a PV+ interneuron) is ~ 10-times more abundant than recurrent inhibition (in which a GC inhibits itself). Thus, unique connectivity rules may enable the dentate gyrus to perform specific higher-order computations. GABAergic interneurons are known to provide inhibition to allow computational function of neuronal network. Here, Espinoza and colleagues show that connectivity of granule cells and interneurons in the dentate gyrus of mouse hippocampus are consistent with the circuit architecture capable of performing a winners-take-all mechanism.
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Affiliation(s)
- Claudia Espinoza
- IST Austria (Institute of Science and Technology Austria), Am Campus 1, 3400, Klosterneuburg, Austria
| | - Segundo Jose Guzman
- Institute for Molecular Biotechnology (IMBA), Dr. Bohr-Gasse 3, 1030, Wien, Austria
| | - Xiaomin Zhang
- IST Austria (Institute of Science and Technology Austria), Am Campus 1, 3400, Klosterneuburg, Austria
| | - Peter Jonas
- IST Austria (Institute of Science and Technology Austria), Am Campus 1, 3400, Klosterneuburg, Austria.
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120
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Bolding KA, Franks KM. Recurrent cortical circuits implement concentration-invariant odor coding. Science 2018; 361:361/6407/eaat6904. [PMID: 30213885 DOI: 10.1126/science.aat6904] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Accepted: 08/03/2018] [Indexed: 12/28/2022]
Abstract
Animals rely on olfaction to find food, attract mates, and avoid predators. To support these behaviors, they must be able to identify odors across different odorant concentrations. The neural circuit operations that implement this concentration invariance remain unclear. We found that despite concentration-dependence in the olfactory bulb (OB), representations of odor identity were preserved downstream, in the piriform cortex (PCx). The OB cells responding earliest after inhalation drove robust responses in sparse subsets of PCx neurons. Recurrent collateral connections broadcast their activation across the PCx, recruiting global feedback inhibition that rapidly truncated and suppressed cortical activity for the remainder of the sniff, discounting the impact of slower, concentration-dependent OB inputs. Eliminating recurrent collateral output amplified PCx odor responses rendered the cortex steeply concentration-dependent and abolished concentration-invariant identity decoding.
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Affiliation(s)
- Kevin A Bolding
- Department of Neurobiology, Duke University Medical School, Durham, NC, USA
| | - Kevin M Franks
- Department of Neurobiology, Duke University Medical School, Durham, NC, USA.
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121
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Developmental Coordination during Olfactory Circuit Remodeling in Drosophila. Neuron 2018; 99:1204-1215.e5. [PMID: 30146303 DOI: 10.1016/j.neuron.2018.07.050] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 06/03/2018] [Accepted: 07/27/2018] [Indexed: 02/03/2023]
Abstract
Developmental neuronal remodeling is crucial for proper wiring of the adult nervous system. While remodeling of individual neuronal populations has been studied, how neuronal circuits remodel-and whether remodeling of synaptic partners is coordinated-is unknown. We found that the Drosophila anterior paired lateral (APL) neuron undergoes stereotypic remodeling during metamorphosis in a similar time frame as the mushroom body (MB) ɣ-neurons, with whom it forms a functional circuit. By simultaneously manipulating both neuronal populations, we found that cell-autonomous inhibition of ɣ-neuron pruning resulted in the inhibition of APL pruning in a process that is mediated, at least in part, by Ca2+-Calmodulin and neuronal activity dependent interaction. Finally, ectopic unpruned MB ɣ axons display ectopic connections with the APL, as well as with other neurons, at the adult, suggesting that inhibiting remodeling of one neuronal type can affect the functional wiring of the entire micro-circuit.
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122
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Srinivasan S, Greenspan RJ, Stevens CF, Grover D. Deep(er) Learning. J Neurosci 2018; 38:7365-7374. [PMID: 30006366 PMCID: PMC6596136 DOI: 10.1523/jneurosci.0153-18.2018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 06/30/2018] [Accepted: 07/05/2018] [Indexed: 12/30/2022] Open
Abstract
Animals successfully thrive in noisy environments with finite resources. The necessity to function with resource constraints has led evolution to design animal brains (and bodies) to be optimal in their use of computational power while being adaptable to their environmental niche. A key process undergirding this ability to adapt is the process of learning. Although a complete characterization of the neural basis of learning remains ongoing, scientists for nearly a century have used the brain as inspiration to design artificial neural networks capable of learning, a case in point being deep learning. In this viewpoint, we advocate that deep learning can be further enhanced by incorporating and tightly integrating five fundamental principles of neural circuit design and function: optimizing the system to environmental need and making it robust to environmental noise, customizing learning to context, modularizing the system, learning without supervision, and learning using reinforcement strategies. We illustrate how animals integrate these learning principles using the fruit fly olfactory learning circuit, one of nature's best-characterized and highly optimized schemes for learning. Incorporating these principles may not just improve deep learning but also expose common computational constraints. With judicious use, deep learning can become yet another effective tool to understand how and why brains are designed the way they are.
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Affiliation(s)
- Shyam Srinivasan
- Kavli Institute for Brain and Mind, University of California-San Diego, La Jolla, California 92093
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, California 92037
| | - Ralph J Greenspan
- Kavli Institute for Brain and Mind, University of California-San Diego, La Jolla, California 92093
- Division of Biological Sciences, University of California-San Diego, La Jolla, California 92093, and
- Department of Cognitive Science, University of California-San Diego, La Jolla, California 92093
| | - Charles F Stevens
- Kavli Institute for Brain and Mind, University of California-San Diego, La Jolla, California 92093,
- Molecular Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, California 92037
| | - Dhruv Grover
- Kavli Institute for Brain and Mind, University of California-San Diego, La Jolla, California 92093,
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123
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Zwaka H, Bartels R, Grünewald B, Menzel R. Neural Organization of A3 Mushroom Body Extrinsic Neurons in the Honeybee Brain. Front Neuroanat 2018; 12:57. [PMID: 30127725 PMCID: PMC6089341 DOI: 10.3389/fnana.2018.00057] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 06/20/2018] [Indexed: 11/20/2022] Open
Abstract
In the insect brain, the mushroom body is a higher order brain area that is key to memory formation and sensory processing. Mushroom body (MB) extrinsic neurons leaving the output region of the MB, the lobes and the peduncle, are thought to be especially important in these processes. In the honeybee brain, a distinct class of MB extrinsic neurons, A3 neurons, are implicated in playing a role in learning. Their MB arborisations are either restricted to the lobes and the peduncle, here called A3 lobe connecting neurons, or they provide feedback information from the lobes to the input region of the MB, the calyces, here called A3 feedback neurons. In this study, we analyzed the morphology of individual A3 lobe connecting and feedback neurons using confocal imaging. A3 feedback neurons were previously assumed to innervate each lip compartment homogenously. We demonstrate here that A3 feedback neurons do not innervate whole subcompartments, but rather innervate zones of varying sizes in the MB lip, collar, and basal ring. We describe for the first time the anatomical details of A3 lobe connecting neurons and show that their connection pattern in the lobes resemble those of A3 feedback cells. Previous studies showed that A3 feedback neurons mostly connect zones of the vertical lobe that receive input from Kenyon cells of distinct calycal subcompartments with the corresponding subcompartments of the calyces. We can show that this also applies to the neck of the peduncle and the medial lobe, where both types of A3 neurons arborize only in corresponding zones in the calycal subcompartments. Some A3 lobe connecting neurons however connect multiple vertical lobe areas. Contrarily, in the medial lobe, the A3 neurons only innervate one division. We found evidence for both input and output areas in the vertical lobe. Thus, A3 neurons are more diverse than previously thought. The understanding of their detailed anatomy might enable us to derive circuit models for learning and memory and test physiological data.
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Affiliation(s)
- Hanna Zwaka
- Institute of Neurobiology, Free University Berlin, Berlin, Germany
- Molecular and Cellular Biology, Harvard University, Cambridge, MA, United States
| | - Ruth Bartels
- Institute of Neurobiology, Free University Berlin, Berlin, Germany
| | - Bernd Grünewald
- Institut für Bienenkunde Oberursel, Goethe University Frankfurt, Frankfurt, Germany
| | - Randolf Menzel
- Institute of Neurobiology, Free University Berlin, Berlin, Germany
- Bernstein Center for Computational Neuroscience, Berlin, Germany
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124
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Zheng Z, Lauritzen JS, Perlman E, Robinson CG, Nichols M, Milkie D, Torrens O, Price J, Fisher CB, Sharifi N, Calle-Schuler SA, Kmecova L, Ali IJ, Karsh B, Trautman ET, Bogovic JA, Hanslovsky P, Jefferis GSXE, Kazhdan M, Khairy K, Saalfeld S, Fetter RD, Bock DD. A Complete Electron Microscopy Volume of the Brain of Adult Drosophila melanogaster. Cell 2018; 174:730-743.e22. [PMID: 30033368 PMCID: PMC6063995 DOI: 10.1016/j.cell.2018.06.019] [Citation(s) in RCA: 457] [Impact Index Per Article: 76.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 02/28/2018] [Accepted: 06/10/2018] [Indexed: 12/16/2022]
Abstract
Drosophila melanogaster has a rich repertoire of innate and learned behaviors. Its 100,000-neuron brain is a large but tractable target for comprehensive neural circuit mapping. Only electron microscopy (EM) enables complete, unbiased mapping of synaptic connectivity; however, the fly brain is too large for conventional EM. We developed a custom high-throughput EM platform and imaged the entire brain of an adult female fly at synaptic resolution. To validate the dataset, we traced brain-spanning circuitry involving the mushroom body (MB), which has been extensively studied for its role in learning. All inputs to Kenyon cells (KCs), the intrinsic neurons of the MB, were mapped, revealing a previously unknown cell type, postsynaptic partners of KC dendrites, and unexpected clustering of olfactory projection neurons. These reconstructions show that this freely available EM volume supports mapping of brain-spanning circuits, which will significantly accelerate Drosophila neuroscience. VIDEO ABSTRACT.
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Affiliation(s)
- Zhihao Zheng
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - J Scott Lauritzen
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Eric Perlman
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Camenzind G Robinson
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Matthew Nichols
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | | | - Omar Torrens
- Coleman Technologies, Newtown Square, PA 19073, USA
| | - John Price
- Hudson Price Designs, Hingham, MA 02043, USA
| | - Corey B Fisher
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Nadiya Sharifi
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | | | - Lucia Kmecova
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Iqbal J Ali
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Bill Karsh
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Eric T Trautman
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - John A Bogovic
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Philipp Hanslovsky
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Gregory S X E Jefferis
- Division of Neurobiology, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK; Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, UK
| | - Michael Kazhdan
- Department of Computer Science, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Khaled Khairy
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Stephan Saalfeld
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Richard D Fetter
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Davi D Bock
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA.
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125
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Sugie A, Marchetti G, Tavosanis G. Structural aspects of plasticity in the nervous system of Drosophila. Neural Dev 2018; 13:14. [PMID: 29960596 PMCID: PMC6026517 DOI: 10.1186/s13064-018-0111-z] [Citation(s) in RCA: 24] [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: 12/22/2017] [Accepted: 06/12/2018] [Indexed: 12/15/2022] Open
Abstract
Neurons extend and retract dynamically their neurites during development to form complex morphologies and to reach out to their appropriate synaptic partners. Their capacity to undergo structural rearrangements is in part maintained during adult life when it supports the animal's ability to adapt to a changing environment or to form lasting memories. Nonetheless, the signals triggering structural plasticity and the mechanisms that support it are not yet fully understood at the molecular level. Here, we focus on the nervous system of the fruit fly to ask to which extent activity modulates neuronal morphology and connectivity during development. Further, we summarize the evidence indicating that the adult nervous system of flies retains some capacity for structural plasticity at the synaptic or circuit level. For simplicity, we selected examples mostly derived from studies on the visual system and on the mushroom body, two regions of the fly brain with extensively studied neuroanatomy.
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Affiliation(s)
- Atsushi Sugie
- Center for Transdisciplinary Research, Niigata University, Niigata, 951-8585 Japan
- Brain Research Institute, Niigata University, Niigata, 951-8585 Japan
| | | | - Gaia Tavosanis
- Center for Neurodegenerative Diseases (DZNE), 53127 Bonn, Germany
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126
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Sato S, Ueno K, Saitoe M, Sakai T. Synaptic depression induced by postsynaptic cAMP production in the Drosophila mushroom body calyx. J Physiol 2018; 596:2447-2461. [PMID: 29659025 DOI: 10.1113/jp275799] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 04/06/2018] [Indexed: 12/15/2022] Open
Abstract
KEY POINTS Synaptic potentiation in Drosophila is observed at cholinergic synapses between antennal lobe (AL) and mushroom body (MB) neurons in the adult brain; however, depression at the AL-MB synapses has not yet been identified. By ex vivo Ca2+ imaging in an isolated cultured Drosophila brain, we found novel activity-dependent depression at the AL-MB synapses. The degree of Ca2+ responses after repetitive AL stimulation is significantly reduced in the dendritic region of MB neurons (calyx) compared with those before AL stimulation, and this reduction of Ca2+ responses remains for at least 30 min. The expression of rutabaga, which encodes Ca2+ /calmodulin-dependent adenylyl cyclase, is essential in the MB neurons for the reduction of Ca2+ responses in the calyx. Our study reveals that elevation of cAMP production in the calyx during repetitive AL stimulation induces the depression at the AL-MB synapses. ABSTRACT Synaptic plasticity has been studied to reveal the molecular and cellular mechanisms of associative and non-associative learning. The fruit fly Drosophila melanogaster can be used to identify the molecular mechanisms of synaptic plasticity because vast genetic information or tools are available. Here, by ex vivo Ca2+ imaging of an isolated cultured Drosophila brain, we examined the novel activity-dependent synaptic depression between the projection neurons of the antennal lobe (AL) and mushroom body (MB). Ex vivo Ca2+ imaging analysis revealed that electrical stimulation of AL elicits Ca2+ responses in the dendritic (calyx) and axonal (α lobe) regions of MB neurons, and the responses are reduced after repetitive AL stimulation. Since the cAMP signalling pathway plays an important role in synaptic plasticity in invertebrates and vertebrates, we examined whether the reduction of Ca2+ responses is also regulated by the cAMP signalling pathway. The expression of rutabaga (rut), which encodes Ca2+ /calmodulin-dependent adenylyl cyclase, was essential for the reduction of Ca2+ responses in the calyx and α lobe. Furthermore, imaging analysis using a fluorescence resonance energy transfer-based cAMP indicator revealed that the cAMP level increased in the wild-type calyx during repetitive AL stimulation, whereas it decreased in rut1 mutant flies with a loss-of-function mutation of rut. Thus, our study suggests that an increase in postsynaptic cAMP level during repetitive AL stimulation contributes to the attenuation of inputs at AL-MB synapses.
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Affiliation(s)
- Shoma Sato
- Department of Biological Sciences, Tokyo Metropolitan University, 1-1 Minami-osawa, Hachioji, Tokyo, 1920372, Japan
| | - Kohei Ueno
- Learning and Memory Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo, 1568506, Japan
| | - Minoru Saitoe
- Learning and Memory Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo, 1568506, Japan
| | - Takaomi Sakai
- Department of Biological Sciences, Tokyo Metropolitan University, 1-1 Minami-osawa, Hachioji, Tokyo, 1920372, Japan
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127
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High Precision of Spike Timing across Olfactory Receptor Neurons Allows Rapid Odor Coding in Drosophila. iScience 2018; 4:76-83. [PMID: 30240755 PMCID: PMC6147046 DOI: 10.1016/j.isci.2018.05.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 04/19/2018] [Accepted: 05/14/2018] [Indexed: 01/10/2023] Open
Abstract
In recent years, it has become evident that olfaction is a fast sense, and millisecond short differences in stimulus onsets are used by animals to analyze their olfactory environment. In contrast, olfactory receptor neurons are thought to be relatively slow and temporally imprecise. These observations have led to a conundrum: how, then, can an animal resolve fast stimulus dynamics and smell with high temporal acuity? Using parallel recordings from olfactory receptor neurons in Drosophila, we found hitherto unknown fast and temporally precise odorant-evoked spike responses, with first spike latencies (relative to odorant arrival) down to 3 ms and with a SD below 1 ms. These data provide new upper bounds for the speed of olfactory processing and suggest that the insect olfactory system could use the precise spike timing for olfactory coding and computation, which can explain insects' rapid processing of temporal stimuli when encountering turbulent odor plumes. Olfactory receptor neuron responses are fast and temporally precise Odor-evoked spikes can occur 3 ms after odorant arrival and jitter less than 1 ms First-spike timing varies over a wider concentration range than spike rate Neural network model demonstrates the plausibility of a spike-timing code for odors
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128
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Lüdke A, Raiser G, Nehrkorn J, Herz AVM, Galizia CG, Szyszka P. Calcium in Kenyon Cell Somata as a Substrate for an Olfactory Sensory Memory in Drosophila. Front Cell Neurosci 2018; 12:128. [PMID: 29867361 PMCID: PMC5960692 DOI: 10.3389/fncel.2018.00128] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 04/23/2018] [Indexed: 12/31/2022] Open
Abstract
Animals can form associations between temporally separated stimuli. To do so, the nervous system has to retain a neural representation of the first stimulus until the second stimulus appears. The neural substrate of such sensory stimulus memories is unknown. Here, we search for a sensory odor memory in the insect olfactory system and characterize odorant-evoked Ca2+ activity at three consecutive layers of the olfactory system in Drosophila: in olfactory receptor neurons (ORNs) and projection neurons (PNs) in the antennal lobe, and in Kenyon cells (KCs) in the mushroom body. We show that the post-stimulus responses in ORN axons, PN dendrites, PN somata, and KC dendrites are odor-specific, but they are not predictive of the chemical identity of past olfactory stimuli. However, the post-stimulus responses in KC somata carry information about the identity of previous olfactory stimuli. These findings show that the Ca2+ dynamics in KC somata could encode a sensory memory of odorant identity and thus might serve as a basis for associations between temporally separated stimuli.
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Affiliation(s)
- Alja Lüdke
- Department of Biology, Neurobiology, University of Konstanz, Konstanz, Germany
| | - Georg Raiser
- Department of Biology, Neurobiology, University of Konstanz, Konstanz, Germany
- International Max Planck Research School for Organismal Biology, Konstanz, Germany
| | - Johannes Nehrkorn
- Fakultät für Biologie, Ludwig-Maximilians-Universität München, Martinsried, Germany
- Bernstein Center for Computational Neuroscience, Munich, Germany
| | - Andreas V. M. Herz
- Fakultät für Biologie, Ludwig-Maximilians-Universität München, Martinsried, Germany
- Bernstein Center for Computational Neuroscience, Munich, Germany
| | - C. Giovanni Galizia
- Department of Biology, Neurobiology, University of Konstanz, Konstanz, Germany
| | - Paul Szyszka
- Department of Biology, Neurobiology, University of Konstanz, Konstanz, Germany
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129
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Cabirol A, Cope AJ, Barron AB, Devaud JM. Relationship between brain plasticity, learning and foraging performance in honey bees. PLoS One 2018; 13:e0196749. [PMID: 29709023 PMCID: PMC5927457 DOI: 10.1371/journal.pone.0196749] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 04/18/2018] [Indexed: 12/16/2022] Open
Abstract
Brain structure and learning capacities both vary with experience, but the mechanistic link between them is unclear. Here, we investigated whether experience-dependent variability in learning performance can be explained by neuroplasticity in foraging honey bees. The mushroom bodies (MBs) are a brain center necessary for ambiguous olfactory learning tasks such as reversal learning. Using radio frequency identification technology, we assessed the effects of natural variation in foraging activity, and the age when first foraging, on both performance in reversal learning and on synaptic connectivity in the MBs. We found that reversal learning performance improved at foraging onset and could decline with greater foraging experience. If bees started foraging before the normal age, as a result of a stress applied to the colony, the decline in learning performance with foraging experience was more severe. Analyses of brain structure in the same bees showed that the total number of synaptic boutons at the MB input decreased when bees started foraging, and then increased with greater foraging intensity. At foraging onset MB structure is therefore optimized for bees to update learned information, but optimization of MB connectivity deteriorates with foraging effort. In a computational model of the MBs sparser coding of information at the MB input improved reversal learning performance. We propose, therefore, a plausible mechanistic relationship between experience, neuroplasticity, and cognitive performance in a natural and ecological context.
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Affiliation(s)
- Amélie Cabirol
- Department of Biological Sciences, Macquarie University, North Ryde, NSW, Australia
- Research Center on Animal Cognition, Center for Integrative Biology, Toulouse University, CNRS, UPS, Toulouse, France
- * E-mail: (AC); (ABB)
| | - Alex J. Cope
- Department of Computer Science, University of Sheffield, Sheffield, South Yorkshire, United Kingdom
| | - Andrew B. Barron
- Department of Biological Sciences, Macquarie University, North Ryde, NSW, Australia
- * E-mail: (AC); (ABB)
| | - Jean-Marc Devaud
- Research Center on Animal Cognition, Center for Integrative Biology, Toulouse University, CNRS, UPS, Toulouse, France
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130
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Dendritic Integration of Sensory Evidence in Perceptual Decision-Making. Cell 2018; 173:894-905.e13. [PMID: 29706545 PMCID: PMC5947940 DOI: 10.1016/j.cell.2018.03.075] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 01/30/2018] [Accepted: 03/28/2018] [Indexed: 12/11/2022]
Abstract
Perceptual decisions require the accumulation of sensory information to a response criterion. Most accounts of how the brain performs this process of temporal integration have focused on evolving patterns of spiking activity. We report that subthreshold changes in membrane voltage can represent accumulating evidence before a choice. αβ core Kenyon cells (αβc KCs) in the mushroom bodies of fruit flies integrate odor-evoked synaptic inputs to action potential threshold at timescales matching the speed of olfactory discrimination. The forkhead box P transcription factor (FoxP) sets neuronal integration and behavioral decision times by controlling the abundance of the voltage-gated potassium channel Shal (KV4) in αβc KC dendrites. αβc KCs thus tailor, through a particular constellation of biophysical properties, the generic process of synaptic integration to the demands of sequential sampling.
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131
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Cognigni P, Felsenberg J, Waddell S. Do the right thing: neural network mechanisms of memory formation, expression and update in Drosophila. Curr Opin Neurobiol 2018; 49:51-58. [PMID: 29258011 PMCID: PMC5981003 DOI: 10.1016/j.conb.2017.12.002] [Citation(s) in RCA: 142] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 12/05/2017] [Accepted: 12/06/2017] [Indexed: 12/02/2022]
Abstract
When animals learn, plasticity in brain networks that respond to specific cues results in a change in the behavior that these cues elicit. Individual network components in the mushroom bodies of the fruit fly Drosophila melanogaster represent cues, learning signals and behavioral outcomes of learned experience. Recent findings have highlighted the importance of dopamine-driven plasticity and activity in feedback and feedforward connections, between various elements of the mushroom body neural network. These computational motifs have been shown to be crucial for long term olfactory memory consolidation, integration of internal states, re-evaluation and updating of learned information. The often recurrent circuit anatomy and a prolonged requirement for activity in parts of these underlying networks, suggest that self-sustained and precisely timed activity is a fundamental feature of network computations in the insect brain. Together these processes allow flies to continuously adjust the content of their learned knowledge and direct their behavior in a way that best represents learned expectations and serves their most pressing current needs.
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Affiliation(s)
- Paola Cognigni
- Centre for Neural Circuit and Behaviour, University of Oxford, Tinsley Building, Mansfield Road, Oxford, United Kingdom
| | - Johannes Felsenberg
- Centre for Neural Circuit and Behaviour, University of Oxford, Tinsley Building, Mansfield Road, Oxford, United Kingdom
| | - Scott Waddell
- Centre for Neural Circuit and Behaviour, University of Oxford, Tinsley Building, Mansfield Road, Oxford, United Kingdom.
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132
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Tsao CH, Chen CC, Lin CH, Yang HY, Lin S. Drosophila mushroom bodies integrate hunger and satiety signals to control innate food-seeking behavior. eLife 2018; 7:35264. [PMID: 29547121 PMCID: PMC5910021 DOI: 10.7554/elife.35264] [Citation(s) in RCA: 90] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 03/15/2018] [Indexed: 12/28/2022] Open
Abstract
The fruit fly can evaluate its energy state and decide whether to pursue food-related cues. Here, we reveal that the mushroom body (MB) integrates hunger and satiety signals to control food-seeking behavior. We have discovered five pathways in the MB essential for hungry flies to locate and approach food. Blocking the MB-intrinsic Kenyon cells (KCs) and the MB output neurons (MBONs) in these pathways impairs food-seeking behavior. Starvation bi-directionally modulates MBON responses to a food odor, suggesting that hunger and satiety controls occur at the KC-to-MBON synapses. These controls are mediated by six types of dopaminergic neurons (DANs). By manipulating these DANs, we could inhibit food-seeking behavior in hungry flies or promote food seeking in fed flies. Finally, we show that the DANs potentially receive multiple inputs of hunger and satiety signals. This work demonstrates an information-rich central circuit in the fly brain that controls hunger-driven food-seeking behavior.
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Affiliation(s)
- Chang-Hui Tsao
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Chien-Chun Chen
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Chen-Han Lin
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan.,Department of Life Sciences and the Institute of Genome Sciences, National Yang-Ming University, Taipei, Taiwan
| | - Hao-Yu Yang
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Suewei Lin
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan.,Department of Life Sciences and the Institute of Genome Sciences, National Yang-Ming University, Taipei, Taiwan
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133
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Kropf J, Rössler W. In-situ recording of ionic currents in projection neurons and Kenyon cells in the olfactory pathway of the honeybee. PLoS One 2018; 13:e0191425. [PMID: 29351552 PMCID: PMC5774781 DOI: 10.1371/journal.pone.0191425] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 01/04/2018] [Indexed: 11/18/2022] Open
Abstract
The honeybee olfactory pathway comprises an intriguing pattern of convergence and divergence: ~60.000 olfactory sensory neurons (OSN) convey olfactory information on ~900 projection neurons (PN) in the antennal lobe (AL). To transmit this information reliably, PNs employ relatively high spiking frequencies with complex patterns. PNs project via a dual olfactory pathway to the mushroom bodies (MB). This pathway comprises the medial (m-ALT) and the lateral antennal lobe tract (l-ALT). PNs from both tracts transmit information from a wide range of similar odors, but with distinct differences in coding properties. In the MBs, PNs form synapses with many Kenyon cells (KC) that encode odors in a spatially and temporally sparse way. The transformation from complex information coding to sparse coding is a well-known phenomenon in insect olfactory coding. Intrinsic neuronal properties as well as GABAergic inhibition are thought to contribute to this change in odor representation. In the present study, we identified intrinsic neuronal properties promoting coding differences between PNs and KCs using in-situ patch-clamp recordings in the intact brain. We found very prominent K+ currents in KCs clearly differing from the PN currents. This suggests that odor coding differences between PNs and KCs may be caused by differences in their specific ion channel properties. Comparison of ionic currents of m- and l-ALT PNs did not reveal any differences at a qualitative level.
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Affiliation(s)
- Jan Kropf
- Behavioral Physiology and Sociobiology (Zoology II), Biozentrum, University of Würzburg, Würzburg, Germany
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford, United Kingdom
- * E-mail:
| | - Wolfgang Rössler
- Behavioral Physiology and Sociobiology (Zoology II), Biozentrum, University of Würzburg, Würzburg, Germany
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134
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Dasgupta S, Stevens CF, Navlakha S. A neural algorithm for a fundamental computing problem. Science 2017; 358:793-796. [DOI: 10.1126/science.aam9868] [Citation(s) in RCA: 100] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Accepted: 09/25/2017] [Indexed: 12/18/2022]
Abstract
Similarity search—for example, identifying similar images in a database or similar documents on the web—is a fundamental computing problem faced by large-scale information retrieval systems. We discovered that the fruit fly olfactory circuit solves this problem with a variant of a computer science algorithm (called locality-sensitive hashing). The fly circuit assigns similar neural activity patterns to similar odors, so that behaviors learned from one odor can be applied when a similar odor is experienced. The fly algorithm, however, uses three computational strategies that depart from traditional approaches. These strategies can be translated to improve the performance of computational similarity searches. This perspective helps illuminate the logic supporting an important sensory function and provides a conceptually new algorithm for solving a fundamental computational problem.
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Affiliation(s)
- Sanjoy Dasgupta
- Department of Computer Science and Engineering, University of California San Diego, La Jolla, CA, USA
| | - Charles F. Stevens
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA, USA
- Kavli Institute for Brain and Mind, University of California San Diego, La Jolla, CA, USA
| | - Saket Navlakha
- Integrative Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA, USA
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135
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Sparse synaptic connectivity is required for decorrelation and pattern separation in feedforward networks. Nat Commun 2017; 8:1116. [PMID: 29061964 PMCID: PMC5653655 DOI: 10.1038/s41467-017-01109-y] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 08/18/2017] [Indexed: 11/17/2022] Open
Abstract
Pattern separation is a fundamental function of the brain. The divergent feedforward networks thought to underlie this computation are widespread, yet exhibit remarkably similar sparse synaptic connectivity. Marr-Albus theory postulates that such networks separate overlapping activity patterns by mapping them onto larger numbers of sparsely active neurons. But spatial correlations in synaptic input and those introduced by network connectivity are likely to compromise performance. To investigate the structural and functional determinants of pattern separation we built models of the cerebellar input layer with spatially correlated input patterns, and systematically varied their synaptic connectivity. Performance was quantified by the learning speed of a classifier trained on either the input or output patterns. Our results show that sparse synaptic connectivity is essential for separating spatially correlated input patterns over a wide range of network activity, and that expansion and correlations, rather than sparse activity, are the major determinants of pattern separation. Input decorrelation, expansion recoding and sparse activity have been proposed to separate overlapping activity patterns in feedforward networks. Here the authors use reduced and detailed spiking models to elucidate how synaptic connectivity affects the contribution of these mechanisms to pattern separation in cerebellar cortex.
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136
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Wolff GH, Thoen HH, Marshall J, Sayre ME, Strausfeld NJ. An insect-like mushroom body in a crustacean brain. eLife 2017; 6:29889. [PMID: 28949916 PMCID: PMC5614564 DOI: 10.7554/elife.29889] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 08/25/2017] [Indexed: 01/02/2023] Open
Abstract
Mushroom bodies are the iconic learning and memory centers of insects. No previously described crustacean possesses a mushroom body as defined by strict morphological criteria although crustacean centers called hemiellipsoid bodies, which serve functions in sensory integration, have been viewed as evolutionarily convergent with mushroom bodies. Here, using key identifiers to characterize neural arrangements, we demonstrate insect-like mushroom bodies in stomatopod crustaceans (mantis shrimps). More than any other crustacean taxon, mantis shrimps display sophisticated behaviors relating to predation, spatial memory, and visual recognition comparable to those of insects. However, neuroanatomy-based cladistics suggesting close phylogenetic proximity of insects and stomatopod crustaceans conflicts with genomic evidence showing hexapods closely related to simple crustaceans called remipedes. We discuss whether corresponding anatomical phenotypes described here reflect the cerebral morphology of a common ancestor of Pancrustacea or an extraordinary example of convergent evolution. With more than four million species, arthropods are the largest and most diverse group of animals on the planet and include, for example, crustaceans, insects and spiders. They are defined by their segmented bodies, hard outer skeletons and jointed limbs. All arthropods share a common ancestor that lived more than 550 million years ago. Exactly how this ancestral arthropod gave rise to the myriad species that exist today is unclear but we know that at some point the arthropod family tree split into branches, one of which went on to become the crustaceans. The crustacean branch then split again, giving rise to a line of descendants that would become the insects. But although insects evolved from crustaceans, the brains of insects possess structures that those of crustaceans do not. Known as mushroom bodies, these structures help to form and store memories. Their absence in crustaceans has therefore been an enduring mystery. Wolff et al. now add a piece to the puzzle by showing that one group of modern-day crustaceans, the mantis shrimps, does in fact possess mushroom bodies. By visualizing cells and pathways within the brains of mantis shrimps, and also a number of closely related species, Wolff et al. show that only these shrimps possess true mushroom bodies. However, some of the mantis shrimp’s close relatives possess a few attributes of these structures. This suggests that mushroom bodies are evolutionarily ancient structures that arose in a common ancestor of insects and crustaceans, before being lost or radically modified in most of the crustaceans. So why did this happen? Mantis shrimps are top predators with excellent vision that hunt over considerable distances, requiring them to evaluate and memorize complex features of their environment. These cognitive demands, which might not be shared by other crustaceans, may have led to the mantis shrimps retaining their mushroom bodies. Further research into the brains and behavior of the mantis shrimp may provide insights into how mushroom bodies construct memories of a complex sensory world.
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Affiliation(s)
| | | | - Justin Marshall
- Sensory Neurobiology Group, University of Queensland, Brisbane, Australia
| | - Marcel E Sayre
- Department of Neuroscience, School of Mind, Brain and Behavior, University of Arizona, Tucson, United States
| | - Nicholas James Strausfeld
- Department of Neuroscience, School of Mind, Brain and Behavior, University of Arizona, Tucson, United States
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137
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Origins of Cell-Type-Specific Olfactory Processing in the Drosophila Mushroom Body Circuit. Neuron 2017; 95:357-367.e4. [PMID: 28728024 DOI: 10.1016/j.neuron.2017.06.039] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 05/23/2017] [Accepted: 06/23/2017] [Indexed: 11/23/2022]
Abstract
How cell-type-specific physiological properties shape neuronal functions in a circuit remains poorly understood. We addressed this issue in the Drosophila mushroom body (MB), a higher olfactory circuit, where neurons belonging to distinct glomeruli in the antennal lobe feed excitation to three types of intrinsic neurons, α/β, α'/β', and γ Kenyon cells (KCs). Two-photon optogenetics and intracellular recording revealed that whereas glomerular inputs add similarly in all KCs, spikes were generated most readily in α'/β' KCs. This cell type was also the most competent in recruiting GABAergic inhibition fed back by anterior paired lateral neuron, which responded to odors either locally within a lobe or globally across all lobes depending on the strength of stimuli. Notably, as predicted from these physiological properties, α'/β' KCs had the highest odor detection speed, sensitivity, and discriminability. This enhanced discrimination required proper GABAergic inhibition. These results link cell-type-specific mechanisms and functions in the MB circuit.
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138
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Eichler K, Li F, Litwin-Kumar A, Park Y, Andrade I, Schneider-Mizell CM, Saumweber T, Huser A, Eschbach C, Gerber B, Fetter RD, Truman JW, Priebe CE, Abbott LF, Thum AS, Zlatic M, Cardona A. The complete connectome of a learning and memory centre in an insect brain. Nature 2017; 548:175-182. [PMID: 28796202 PMCID: PMC5806122 DOI: 10.1038/nature23455] [Citation(s) in RCA: 275] [Impact Index Per Article: 39.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Accepted: 07/04/2017] [Indexed: 12/19/2022]
Abstract
Associating stimuli with positive or negative reinforcement is essential for survival, but a complete wiring diagram of a higher-order circuit supporting associative memory has not been previously available. Here we reconstruct one such circuit at synaptic resolution, the Drosophila larval mushroom body. We find that most Kenyon cells integrate random combinations of inputs but that a subset receives stereotyped inputs from single projection neurons. This organization maximizes performance of a model output neuron on a stimulus discrimination task. We also report a novel canonical circuit in each mushroom body compartment with previously unidentified connections: reciprocal Kenyon cell to modulatory neuron connections, modulatory neuron to output neuron connections, and a surprisingly high number of recurrent connections between Kenyon cells. Stereotyped connections found between output neurons could enhance the selection of learned behaviours. The complete circuit map of the mushroom body should guide future functional studies of this learning and memory centre.
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Affiliation(s)
- Katharina Eichler
- Howard Hughes Medical Institute Janelia Research Campus, 19700 Helix Drive, Ashburn, Virginia 20147, USA
- Department of Biology, University of Konstanz, Universitätsstrasse 10, 78464 Konstanz, Germany
| | - Feng Li
- Howard Hughes Medical Institute Janelia Research Campus, 19700 Helix Drive, Ashburn, Virginia 20147, USA
| | - Ashok Litwin-Kumar
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Department of Neuroscience, Columbia University, 3227 Broadway, New York, New York 10027, USA
| | - Youngser Park
- Department of Applied Mathematics and Statistics, Whiting School of Engineering, Johns Hopkins University, 100 Whitehead Hall, 3400 North Charles Street, Baltimore, Maryland 21218, USA
| | - Ingrid Andrade
- Howard Hughes Medical Institute Janelia Research Campus, 19700 Helix Drive, Ashburn, Virginia 20147, USA
| | - Casey M Schneider-Mizell
- Howard Hughes Medical Institute Janelia Research Campus, 19700 Helix Drive, Ashburn, Virginia 20147, USA
| | - Timo Saumweber
- Abteilung Genetik von Lernen und Gedächtnis, Leibniz Institut für Neurobiologie, 39118 Magdeburg, Germany
| | - Annina Huser
- Department of Biology, University of Konstanz, Universitätsstrasse 10, 78464 Konstanz, Germany
| | - Claire Eschbach
- Howard Hughes Medical Institute Janelia Research Campus, 19700 Helix Drive, Ashburn, Virginia 20147, USA
| | - Bertram Gerber
- Abteilung Genetik von Lernen und Gedächtnis, Leibniz Institut für Neurobiologie, 39118 Magdeburg, Germany
- Otto von Guericke Universität Magdeburg, Institut für Biologie, Verhaltensgenetik, Universitätsplatz 2, D-39106 Magdeburg, Germany
- Otto-von-Guericke University Magdeburg, Center for Behavioral Brain Sciences, Universitätsplatz 2, D-39106 Magdeburg, Germany
| | - Richard D Fetter
- Howard Hughes Medical Institute Janelia Research Campus, 19700 Helix Drive, Ashburn, Virginia 20147, USA
| | - James W Truman
- Howard Hughes Medical Institute Janelia Research Campus, 19700 Helix Drive, Ashburn, Virginia 20147, USA
| | - Carey E Priebe
- Department of Applied Mathematics and Statistics, Whiting School of Engineering, Johns Hopkins University, 100 Whitehead Hall, 3400 North Charles Street, Baltimore, Maryland 21218, USA
| | - L F Abbott
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Department of Neuroscience, Columbia University, 3227 Broadway, New York, New York 10027, USA
- Department of Physiology and Cellular Biophysics, Columbia University, Russ Berrie Pavilion, 1150 St Nicholas Avenue, New York, New York 10032, USA
| | - Andreas S Thum
- Department of Biology, University of Konstanz, Universitätsstrasse 10, 78464 Konstanz, Germany
| | - Marta Zlatic
- Howard Hughes Medical Institute Janelia Research Campus, 19700 Helix Drive, Ashburn, Virginia 20147, USA
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK
| | - Albert Cardona
- Howard Hughes Medical Institute Janelia Research Campus, 19700 Helix Drive, Ashburn, Virginia 20147, USA
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3DY, UK
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139
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Takemura SY, Aso Y, Hige T, Wong A, Lu Z, Xu CS, Rivlin PK, Hess H, Zhao T, Parag T, Berg S, Huang G, Katz W, Olbris DJ, Plaza S, Umayam L, Aniceto R, Chang LA, Lauchie S, Ogundeyi O, Ordish C, Shinomiya A, Sigmund C, Takemura S, Tran J, Turner GC, Rubin GM, Scheffer LK. A connectome of a learning and memory center in the adult Drosophila brain. eLife 2017; 6. [PMID: 28718765 PMCID: PMC5550281 DOI: 10.7554/elife.26975] [Citation(s) in RCA: 225] [Impact Index Per Article: 32.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2017] [Accepted: 07/17/2017] [Indexed: 12/12/2022] Open
Abstract
Understanding memory formation, storage and retrieval requires knowledge of the underlying neuronal circuits. In Drosophila, the mushroom body (MB) is the major site of associative learning. We reconstructed the morphologies and synaptic connections of all 983 neurons within the three functional units, or compartments, that compose the adult MB’s α lobe, using a dataset of isotropic 8 nm voxels collected by focused ion-beam milling scanning electron microscopy. We found that Kenyon cells (KCs), whose sparse activity encodes sensory information, each make multiple en passant synapses to MB output neurons (MBONs) in each compartment. Some MBONs have inputs from all KCs, while others differentially sample sensory modalities. Only 6% of KC>MBON synapses receive a direct synapse from a dopaminergic neuron (DAN). We identified two unanticipated classes of synapses, KC>DAN and DAN>MBON. DAN activation produces a slow depolarization of the MBON in these DAN>MBON synapses and can weaken memory recall. DOI:http://dx.doi.org/10.7554/eLife.26975.001
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Affiliation(s)
- Shin-Ya Takemura
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Yoshinori Aso
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Toshihide Hige
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Allan Wong
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Zhiyuan Lu
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - C Shan Xu
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Patricia K Rivlin
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Harald Hess
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Ting Zhao
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Toufiq Parag
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Stuart Berg
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Gary Huang
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - William Katz
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Donald J Olbris
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Stephen Plaza
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Lowell Umayam
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Roxanne Aniceto
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Lei-Ann Chang
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Shirley Lauchie
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Omotara Ogundeyi
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Christopher Ordish
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Aya Shinomiya
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Christopher Sigmund
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Satoko Takemura
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Julie Tran
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Glenn C Turner
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Gerald M Rubin
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Louis K Scheffer
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
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140
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Dylla KV, Raiser G, Galizia CG, Szyszka P. Trace Conditioning in Drosophila Induces Associative Plasticity in Mushroom Body Kenyon Cells and Dopaminergic Neurons. Front Neural Circuits 2017; 11:42. [PMID: 28676744 PMCID: PMC5476701 DOI: 10.3389/fncir.2017.00042] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 05/29/2017] [Indexed: 02/04/2023] Open
Abstract
Dopaminergic neurons (DANs) signal punishment and reward during associative learning. In mammals, DANs show associative plasticity that correlates with the discrepancy between predicted and actual reinforcement (prediction error) during classical conditioning. Also in insects, such as Drosophila, DANs show associative plasticity that is, however, less understood. Here, we study associative plasticity in DANs and their synaptic partners, the Kenyon cells (KCs) in the mushroom bodies (MBs), while training Drosophila to associate an odorant with a temporally separated electric shock (trace conditioning). In most MB compartments DANs strengthened their responses to the conditioned odorant relative to untrained animals. This response plasticity preserved the initial degree of similarity between the odorant- and the shock-induced spatial response patterns, which decreased in untrained animals. Contrary to DANs, KCs (α'/β'-type) decreased their responses to the conditioned odorant relative to untrained animals. We found no evidence for prediction error coding by DANs during conditioning. Rather, our data supports the hypothesis that DAN plasticity encodes conditioning-induced changes in the odorant's predictive power.
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Affiliation(s)
- Kristina V Dylla
- Department of Biology, Neurobiology, University of KonstanzKonstanz, Germany
| | - Georg Raiser
- Department of Biology, Neurobiology, University of KonstanzKonstanz, Germany
| | - C Giovanni Galizia
- Department of Biology, Neurobiology, University of KonstanzKonstanz, Germany
| | - Paul Szyszka
- Department of Biology, Neurobiology, University of KonstanzKonstanz, Germany
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141
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Krystal JH, Anticevic A, Yang GJ, Dragoi G, Driesen NR, Wang XJ, Murray JD. Impaired Tuning of Neural Ensembles and the Pathophysiology of Schizophrenia: A Translational and Computational Neuroscience Perspective. Biol Psychiatry 2017; 81:874-885. [PMID: 28434616 PMCID: PMC5407407 DOI: 10.1016/j.biopsych.2017.01.004] [Citation(s) in RCA: 138] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Revised: 12/14/2016] [Accepted: 01/04/2017] [Indexed: 10/20/2022]
Abstract
The functional optimization of neural ensembles is central to human higher cognitive functions. When the functions through which neural activity is tuned fail to develop or break down, symptoms and cognitive impairments arise. This review considers ways in which disturbances in the balance of excitation and inhibition might develop and be expressed in cortical networks in association with schizophrenia. This presentation is framed within a developmental perspective that begins with disturbances in glutamate synaptic development in utero. It considers developmental correlates and consequences, including compensatory mechanisms that increase intrinsic excitability or reduce inhibitory tone. It also considers the possibility that these homeostatic increases in excitability have potential negative functional and structural consequences. These negative functional consequences of disinhibition may include reduced working memory-related cortical activity associated with the downslope of the "inverted-U" input-output curve, impaired spatial tuning of neural activity and impaired sparse coding of information, and deficits in the temporal tuning of neural activity and its implication for neural codes. The review concludes by considering the functional significance of noisy activity for neural network function. The presentation draws on computational neuroscience and pharmacologic and genetic studies in animals and humans, particularly those involving N-methyl-D-aspartate glutamate receptor antagonists, to illustrate principles of network regulation that give rise to features of neural dysfunction associated with schizophrenia. While this presentation focuses on schizophrenia, the general principles outlined in the review may have broad implications for considering disturbances in the regulation of neural ensembles in psychiatric disorders.
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Affiliation(s)
- John H. Krystal
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT USA,Department of Neuroscience, Yale University School of Medicine, New Haven, CT USA,Clinical Neuroscience Division, VA National Center for PTSD, VA Connecticut Healthcare System, West Haven, CT USA,Behavioral Health Services, Yale-New Haven Hospital, New Haven, CT USA
| | - Alan Anticevic
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT USA,Department of Psychology, Yale University
| | - Genevieve J. Yang
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT USA,Department of Neuroscience, Yale University School of Medicine, New Haven, CT USA
| | - George Dragoi
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT USA,Department of Neuroscience, Yale University School of Medicine, New Haven, CT USA
| | - Naomi R. Driesen
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT USA,Clinical Neuroscience Division, VA National Center for PTSD, VA Connecticut Healthcare System, West Haven, CT USA
| | | | - John D. Murray
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT USA
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142
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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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143
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Hige T. What can tiny mushrooms in fruit flies tell us about learning and memory? Neurosci Res 2017; 129:8-16. [PMID: 28483586 DOI: 10.1016/j.neures.2017.05.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 04/28/2017] [Accepted: 05/01/2017] [Indexed: 10/19/2022]
Abstract
Nervous systems have evolved to translate external stimuli into appropriate behavioral responses. In an ever-changing environment, flexible adjustment of behavioral choice by experience-dependent learning is essential for the animal's survival. Associative learning is a simple form of learning that is widely observed from worms to humans. To understand the whole process of learning, we need to know how sensory information is represented and transformed in the brain, how it is changed by experience, and how the changes are reflected on motor output. To tackle these questions, studying numerically simple invertebrate nervous systems has a great advantage. In this review, I will feature the Pavlovian olfactory learning in the fruit fly, Drosophila melanogaster. The mushroom body is a key brain area for the olfactory learning in this organism. Recently, comprehensive anatomical information and the genetic tool sets were made available for the mushroom body circuit. This greatly accelerated the physiological understanding of the learning process. One of the key findings was dopamine-induced long-term synaptic plasticity that can alter the representations of stimulus valence. I will mostly focus on the new studies within these few years and discuss what we can possibly learn about the vertebrate systems from this model organism.
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Affiliation(s)
- Toshihide Hige
- Janelia Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, VA 20147, USA.
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144
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Arena E, Arena P, Strauss R, Patané L. Motor-Skill Learning in an Insect Inspired Neuro-Computational Control System. Front Neurorobot 2017; 11:12. [PMID: 28337138 PMCID: PMC5340754 DOI: 10.3389/fnbot.2017.00012] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 02/20/2017] [Indexed: 11/13/2022] Open
Abstract
In nature, insects show impressive adaptation and learning capabilities. The proposed computational model takes inspiration from specific structures of the insect brain: after proposing key hypotheses on the direct involvement of the mushroom bodies (MBs) and on their neural organization, we developed a new architecture for motor learning to be applied in insect-like walking robots. The proposed model is a nonlinear control system based on spiking neurons. MBs are modeled as a nonlinear recurrent spiking neural network (SNN) with novel characteristics, able to memorize time evolutions of key parameters of the neural motor controller, so that existing motor primitives can be improved. The adopted control scheme enables the structure to efficiently cope with goal-oriented behavioral motor tasks. Here, a six-legged structure, showing a steady-state exponentially stable locomotion pattern, is exposed to the need of learning new motor skills: moving through the environment, the structure is able to modulate motor commands and implements an obstacle climbing procedure. Experimental results on a simulated hexapod robot are reported; they are obtained in a dynamic simulation environment and the robot mimicks the structures of Drosophila melanogaster.
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Affiliation(s)
- Eleonora Arena
- Dipartimento di Ingegneria Elettrica, Elettronica, e Informatica, University of Catania Catania, Italy
| | - Paolo Arena
- Dipartimento di Ingegneria Elettrica, Elettronica, e Informatica, University of CataniaCatania, Italy; National Institute of Biostructures and BiosystemsRome, Italy
| | - Roland Strauss
- Institut für Zoologie III (Neurobiologie), University of Mainz Mainz, Germany
| | - Luca Patané
- Dipartimento di Ingegneria Elettrica, Elettronica, e Informatica, University of Catania Catania, Italy
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145
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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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146
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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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147
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Gupta N, Singh SS, Stopfer M. Oscillatory integration windows in neurons. Nat Commun 2016; 7:13808. [PMID: 27976720 PMCID: PMC5171764 DOI: 10.1038/ncomms13808] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 11/02/2016] [Indexed: 11/09/2022] Open
Abstract
Oscillatory synchrony among neurons occurs in many species and brain areas, and has been proposed to help neural circuits process information. One hypothesis states that oscillatory input creates cyclic integration windows: specific times in each oscillatory cycle when postsynaptic neurons become especially responsive to inputs. With paired local field potential (LFP) and intracellular recordings and controlled stimulus manipulations we directly test this idea in the locust olfactory system. We find that inputs arriving in Kenyon cells (KCs) sum most effectively in a preferred window of the oscillation cycle. With a computational model, we show that the non-uniform structure of noise in the membrane potential helps mediate this process. Further experiments performed in vivo demonstrate that integration windows can form in the absence of inhibition and at a broad range of oscillation frequencies. Our results reveal how a fundamental coincidence-detection mechanism in a neural circuit functions to decode temporally organized spiking.
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Affiliation(s)
- Nitin Gupta
- National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA.,Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Swikriti Saran Singh
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Mark Stopfer
- National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
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148
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Kosik KS. Life at Low Copy Number: How Dendrites Manage with So Few mRNAs. Neuron 2016; 92:1168-1180. [DOI: 10.1016/j.neuron.2016.11.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 10/27/2016] [Accepted: 11/02/2016] [Indexed: 01/09/2023]
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149
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Pavlou HJ, Lin AC, Neville MC, Nojima T, Diao F, Chen BE, White BH, Goodwin SF. Neural circuitry coordinating male copulation. eLife 2016; 5:e20713. [PMID: 27855059 PMCID: PMC5114013 DOI: 10.7554/elife.20713] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Accepted: 09/28/2016] [Indexed: 11/13/2022] Open
Abstract
Copulation is the goal of the courtship process, crucial to reproductive success and evolutionary fitness. Identifying the circuitry underlying copulation is a necessary step towards understanding universal principles of circuit operation, and how circuit elements are recruited into the production of ordered action sequences. Here, we identify key sex-specific neurons that mediate copulation in Drosophila, and define a sexually dimorphic motor circuit in the male abdominal ganglion that mediates the action sequence of initiating and terminating copulation. This sexually dimorphic circuit composed of three neuronal classes - motor neurons, interneurons and mechanosensory neurons - controls the mechanics of copulation. By correlating the connectivity, function and activity of these neurons we have determined the logic for how this circuitry is coordinated to generate this male-specific behavior, and sets the stage for a circuit-level dissection of active sensing and modulation of copulatory behavior.
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Affiliation(s)
- Hania J Pavlou
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford, United Kingdom
| | - Andrew C Lin
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford, United Kingdom
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | - Megan C Neville
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford, United Kingdom
| | - Tetsuya Nojima
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford, United Kingdom
| | - Fengqiu Diao
- Laboratory of Molecular Biology, National Institute of Mental Health, Bethesda, United States
| | - Brian E Chen
- Department of Medicine, McGill University, Montréal, Canada
- Department of Neurology and Neurosurgery, McGill University, Montréal, Canada
| | - Benjamin H White
- Laboratory of Molecular Biology, National Institute of Mental Health, Bethesda, United States
| | - Stephen F Goodwin
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford, United Kingdom
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150
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Sjulson L, Cassataro D, DasGupta S, Miesenböck G. Cell-Specific Targeting of Genetically Encoded Tools for Neuroscience. Annu Rev Genet 2016; 50:571-594. [PMID: 27732792 DOI: 10.1146/annurev-genet-120215-035011] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Genetically encoded tools for visualizing and manipulating neurons in vivo have led to significant advances in neuroscience, in large part because of the ability to target expression to specific cell populations of interest. Current methods enable targeting based on marker gene expression, development, anatomical projection pattern, synaptic connectivity, and recent activity as well as combinations of these factors. Here, we review these methods, focusing on issues of practical implementation as well as areas for future improvement.
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Affiliation(s)
- Lucas Sjulson
- Department of Psychiatry, New York University School of Medicine, New York, NY 10016; .,Department of Neuroscience and Physiology, Smilow Neuroscience Program, and New York University Neuroscience Institute, New York, NY 10016
| | - Daniela Cassataro
- Department of Neuroscience and Physiology, Smilow Neuroscience Program, and New York University Neuroscience Institute, New York, NY 10016
| | - Shamik DasGupta
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford, OX1 3SR, United Kingdom; .,Present address: Tata Institute of Fundamental Research, Mumbai, 400005, India
| | - Gero Miesenböck
- Centre for Neural Circuits and Behaviour, University of Oxford, Oxford, OX1 3SR, United Kingdom;
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