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Hou WH, Jariwala M, Wang KY, Seewald A, Lin YL, Liou YC, Ricci A, Ferraguti F, Lien CC, Capogna M. Inhibitory fear memory engram in the mouse central lateral amygdala. Cell Rep 2024; 43:114468. [PMID: 39106862 DOI: 10.1016/j.celrep.2024.114468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 04/29/2024] [Accepted: 06/24/2024] [Indexed: 08/09/2024] Open
Abstract
Engrams, which are cellular substrates of memory traces, have been identified in various brain areas, including the amygdala. While most identified engrams are composed of excitatory, glutamatergic neurons, GABAergic inhibitory engrams have been relatively overlooked. Here, we report the identification of an inhibitory engram in the central lateral amygdala (CeL), a key area for auditory fear conditioning. This engram is primarily composed of GABAergic somatostatin-expressing (SST(+)) and, to a lesser extent, protein kinase C-δ-expressing (PKC-δ(+)) neurons. Fear memory is accompanied by a preferential enhancement of synaptic inhibition onto PKC-δ(+) neurons. Silencing this CeL GABAergic engram disinhibits the activity of targeted extra-amygdaloid areas, selectively increasing the expression of fear. Our findings define the behavioral function of an engram formed exclusively by GABAergic inhibitory neurons in the mammalian brain.
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Affiliation(s)
- Wen-Hsien Hou
- Department of Biomedicine, Aarhus University, Aarhus, Denmark; DANDRITE, The Danish Research Institute of Translational Neuroscience, Aarhus University, Aarhus, Denmark; Center for Proteins in Memory - PROMEMO, Danish National Research Foundation, Aarhus University, Aarhus, Denmark
| | - Meet Jariwala
- Department of Biomedicine, Aarhus University, Aarhus, Denmark; Center for Proteins in Memory - PROMEMO, Danish National Research Foundation, Aarhus University, Aarhus, Denmark
| | - Kai-Yi Wang
- Institute of Neuroscience, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Anna Seewald
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria
| | - Yu-Ling Lin
- Institute of Neuroscience, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Yi-Chen Liou
- Institute of Neuroscience, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Alessia Ricci
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Francesco Ferraguti
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria
| | - Cheng-Chang Lien
- Institute of Neuroscience, National Yang Ming Chiao Tung University, Taipei, Taiwan; Brain Research Center, National Yang Ming Chiao Tung University, Taipei, Taiwan.
| | - Marco Capogna
- Department of Biomedicine, Aarhus University, Aarhus, Denmark; DANDRITE, The Danish Research Institute of Translational Neuroscience, Aarhus University, Aarhus, Denmark; Center for Proteins in Memory - PROMEMO, Danish National Research Foundation, Aarhus University, Aarhus, Denmark
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2
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Dovek L, Marrero K, Zagha E, Santhakumar V. Cellular and circuit features distinguish dentate gyrus semilunar granule cells and granule cells activated during contextual memory formation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.21.608983. [PMID: 39229181 PMCID: PMC11370351 DOI: 10.1101/2024.08.21.608983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2024]
Abstract
The dentate gyrus is critical for spatial memory formation and shows task related activation of cellular ensembles considered as memory engrams. Semilunar granule cells (SGCs), a sparse dentate projection neuron subtype distinct from granule cells (GCs), were recently reported to be enriched among behaviorally activated neurons. However, the mechanisms governing SGC recruitment during memory formation and their role in engram refinement remains unresolved. By examining neurons labeled during contextual memory formation in TRAP2 mice, we empirically tested competing hypotheses for GC and SGC recruitment into memory ensembles. In support of the proposal that more excitable neurons are preferentially recruited into memory ensembles, SGCs showed greater sustained firing than GCs. Additionally, SGCs labeled during memory formation showed less adapting firing than unlabeled SGCs. Our recordings did not reveal glutamatergic connections between behaviorally labeled SGCs and GCs, providing evidence against SGCs driving local circuit feedforward excitation in ensemble recruitment. Contrary to a leading hypothesis, there was little evidence for individual SGCs or labeled neuronal ensembles supporting lateral inhibition of unlabeled neurons. Instead, pairs of GCs and SGCs within labeled neuronal cohorts received more temporally correlated spontaneous excitatory synaptic inputs than labeled-unlabeled neuronal pairs, validating a role for correlated afferent inputs in neuronal ensemble selection. These findings challenge the proposal that SGCs drive dentate GC ensemble refinement, while supporting a role for intrinsic active properties and correlated inputs in preferential SGC recruitment to contextual memory engrams. Impact Statement Evaluation of semilunar granule cell involvement in dentate gyrus contextual memory processing supports recruitment based on intrinsic and input characteristics while revealing limited contribution to ensemble refinement.
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Affiliation(s)
- Laura Dovek
- Biomedical Sciences Graduate Program, University of California Riverside, Riverside, California 92521
- Department of Molecular, Cell and Systems Biology, University of California Riverside, Riverside, California 92521
| | - Krista Marrero
- Department of Molecular, Cell and Systems Biology, University of California Riverside, Riverside, California 92521
| | - Edward Zagha
- Biomedical Sciences Graduate Program, University of California Riverside, Riverside, California 92521
- Neuroscience Graduate Program, University of California Riverside, Riverside, California 92521
- Department of Psychology, University of California Riverside, Riverside, California 92521
| | - Vijayalakshmi Santhakumar
- Biomedical Sciences Graduate Program, University of California Riverside, Riverside, California 92521
- Department of Molecular, Cell and Systems Biology, University of California Riverside, Riverside, California 92521
- Neuroscience Graduate Program, University of California Riverside, Riverside, California 92521
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3
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Subramanian R, Bauman A, Carpenter O, Cho C, Coste G, Dam A, Drake K, Ehnstrom S, Fitzgerald N, Jenkins A, Koolpe H, Liu R, Paserman T, Petersen D, Chavez DS, Rozental S, Thompson H, Tsukuda T, Zweig S, Gall M, Zupan B, Bergstrom H. An Infralimbic Cortex Neuronal Ensemble Encoded During Learning Attenuates Fear Generalization Expression. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.18.608308. [PMID: 39229064 PMCID: PMC11370439 DOI: 10.1101/2024.08.18.608308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 09/05/2024]
Abstract
Generalization allows for experience to flexibly guide behavior when conditions change. A basic physical unit of memory storage and expression in the brain are sparse, distributed groups of neurons known as ensembles (i.e., the engram). The infralimbic (IL) subregion of the ventral medial prefrontal cortex plays a key role in modulating conditioned defensive responses. How IL neuronal ensembles established during learning contribute to generalized responses is unknown. In this set of experiments, generalization was tested in male and female mice by presenting a novel, ambiguous, tone generalization stimulus following Pavlovian defensive (fear) conditioning. The first experiment was designed to test a role for IL in generalization using chemogenetic manipulations. Results show IL bidirectionally regulates defensive behavior. IL silencing promotes a switch in defensive state from vigilant scanning to generalized freezing, while IL stimulation reduces freezing in favor of scanning. Leveraging activity-dependent tagging technology (ArcCreERT2 x eYFP system), a neuronal ensemble, preferentially located in IL superficial layer 2/3, was associated with the generalization stimulus. Remarkably, in the identical discrete location, fewer reactivated neurons were associated with the generalization stimulus at the remote timepoint (30 days) following learning. When an IL neuronal ensemble established during learning was selectively chemogenetically silenced, generalization increased. Conversely, IL neuronal ensemble stimulation reduced generalization. Overall, these data identify a crucial role for IL in suppressing generalized responses. Further, we uncover an IL neuronal ensemble, formed during learning, functions to later attenuate the expression of generalization in the presence of ambiguous threat stimuli.
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Affiliation(s)
- Rajani Subramanian
- Department of Psychological Science, Program in Neuroscience and Behavior, Vassar College, Poughkeepsie NY 12603 USA
| | - Avery Bauman
- Department of Psychological Science, Program in Neuroscience and Behavior, Vassar College, Poughkeepsie NY 12603 USA
| | - Olivia Carpenter
- Department of Psychological Science, Program in Neuroscience and Behavior, Vassar College, Poughkeepsie NY 12603 USA
| | - Chris Cho
- Department of Psychological Science, Program in Neuroscience and Behavior, Vassar College, Poughkeepsie NY 12603 USA
| | - Gabrielle Coste
- Department of Psychological Science, Program in Neuroscience and Behavior, Vassar College, Poughkeepsie NY 12603 USA
| | - Ahona Dam
- Department of Psychological Science, Program in Neuroscience and Behavior, Vassar College, Poughkeepsie NY 12603 USA
| | - Kasey Drake
- Department of Psychological Science, Program in Neuroscience and Behavior, Vassar College, Poughkeepsie NY 12603 USA
| | - Sara Ehnstrom
- Department of Psychological Science, Program in Neuroscience and Behavior, Vassar College, Poughkeepsie NY 12603 USA
| | - Naomi Fitzgerald
- Department of Psychological Science, Program in Neuroscience and Behavior, Vassar College, Poughkeepsie NY 12603 USA
| | - Abigail Jenkins
- Department of Psychological Science, Program in Neuroscience and Behavior, Vassar College, Poughkeepsie NY 12603 USA
| | - Hannah Koolpe
- Department of Psychological Science, Program in Neuroscience and Behavior, Vassar College, Poughkeepsie NY 12603 USA
| | - Runqi Liu
- Department of Psychological Science, Program in Neuroscience and Behavior, Vassar College, Poughkeepsie NY 12603 USA
| | - Tamar Paserman
- Department of Psychological Science, Program in Neuroscience and Behavior, Vassar College, Poughkeepsie NY 12603 USA
| | - David Petersen
- Department of Psychological Science, Program in Neuroscience and Behavior, Vassar College, Poughkeepsie NY 12603 USA
| | - Diego Scala Chavez
- Department of Psychological Science, Program in Neuroscience and Behavior, Vassar College, Poughkeepsie NY 12603 USA
| | - Stefano Rozental
- Department of Psychological Science, Program in Neuroscience and Behavior, Vassar College, Poughkeepsie NY 12603 USA
| | - Hannah Thompson
- Department of Psychological Science, Program in Neuroscience and Behavior, Vassar College, Poughkeepsie NY 12603 USA
| | - Tyler Tsukuda
- Department of Psychological Science, Program in Neuroscience and Behavior, Vassar College, Poughkeepsie NY 12603 USA
| | - Sasha Zweig
- Department of Psychological Science, Program in Neuroscience and Behavior, Vassar College, Poughkeepsie NY 12603 USA
| | - Megan Gall
- Department of Biology, Program in Neuroscience and Behavior, Vassar College, Poughkeepsie NY 12603 USA
| | - Bojana Zupan
- Department of Psychological Science, Program in Neuroscience and Behavior, Vassar College, Poughkeepsie NY 12603 USA
| | - Hadley Bergstrom
- Department of Psychological Science, Program in Neuroscience and Behavior, Vassar College, Poughkeepsie NY 12603 USA
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4
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Santoni G, Astori S, Leleu M, Glauser L, Zamora SA, Schioppa M, Tarulli I, Sandi C, Gräff J. Chromatin plasticity predetermines neuronal eligibility for memory trace formation. Science 2024; 385:eadg9982. [PMID: 39052786 DOI: 10.1126/science.adg9982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 03/01/2024] [Accepted: 05/24/2024] [Indexed: 07/27/2024]
Abstract
Memories are encoded by sparse populations of neurons but how such sparsity arises remains largely unknown. We found that a neuron's eligibility to be recruited into the memory trace depends on its epigenetic state prior to encoding. Principal neurons in the mouse lateral amygdala display intrinsic chromatin plasticity, which when experimentally elevated favors neuronal allocation into the encoding ensemble. Such chromatin plasticity occurred at genomic regions underlying synaptic plasticity and was accompanied by increased neuronal excitability in single neurons in real time. Lastly, optogenetic silencing of the epigenetically altered neurons prevented memory expression, revealing a cell-autonomous relationship between chromatin plasticity and memory trace formation. These results identify the epigenetic state of a neuron as a key factor enabling information encoding.
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Affiliation(s)
- Giulia Santoni
- Laboratory of Neuroepigenetics, Brain Mind Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Simone Astori
- Laboratory of Behavioural Genetics, Brain Mind Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Marion Leleu
- Bioinformatics Competence Center, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Liliane Glauser
- Laboratory of Neuroepigenetics, Brain Mind Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Simon A Zamora
- Laboratory of Neuroepigenetics, Brain Mind Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Myriam Schioppa
- Laboratory of Neuroepigenetics, Brain Mind Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
- The institute of Medical Sciences, School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Aberdeen AB25 2ZD, UK
| | - Isabella Tarulli
- Laboratory of Neuroepigenetics, Brain Mind Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Carmen Sandi
- Laboratory of Behavioural Genetics, Brain Mind Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Johannes Gräff
- Laboratory of Neuroepigenetics, Brain Mind Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
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5
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Delamare G, Tomé DF, Clopath C. Intrinsic Neural Excitability Biases Allocation and Overlap of Memory Engrams. J Neurosci 2024; 44:e0846232024. [PMID: 38561228 PMCID: PMC11112642 DOI: 10.1523/jneurosci.0846-23.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 03/25/2024] [Accepted: 03/25/2024] [Indexed: 04/04/2024] Open
Abstract
Memories are thought to be stored in neural ensembles known as engrams that are specifically reactivated during memory recall. Recent studies have found that memory engrams of two events that happened close in time tend to overlap in the hippocampus and the amygdala, and these overlaps have been shown to support memory linking. It has been hypothesized that engram overlaps arise from the mechanisms that regulate memory allocation itself, involving neural excitability, but the exact process remains unclear. Indeed, most theoretical studies focus on synaptic plasticity and little is known about the role of intrinsic plasticity, which could be mediated by neural excitability and serve as a complementary mechanism for forming memory engrams. Here, we developed a rate-based recurrent neural network that includes both synaptic plasticity and neural excitability. We obtained structural and functional overlap of memory engrams for contexts that are presented close in time, consistent with experimental and computational studies. We then investigated the role of excitability in memory allocation at the network level and unveiled competitive mechanisms driven by inhibition. This work suggests mechanisms underlying the role of intrinsic excitability in memory allocation and linking, and yields predictions regarding the formation and the overlap of memory engrams.
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Affiliation(s)
- Geoffroy Delamare
- Department of Bioengineering, Imperial College London, London SW7 2AZ, UK
| | - Douglas Feitosa Tomé
- Department of Bioengineering, Imperial College London, London SW7 2AZ, UK
- Institute of Science and Technology Austria, Klosterneuburg 3400, Austria
| | - Claudia Clopath
- Department of Bioengineering, Imperial College London, London SW7 2AZ, UK
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6
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Mocle AJ, Ramsaran AI, Jacob AD, Rashid AJ, Luchetti A, Tran LM, Richards BA, Frankland PW, Josselyn SA. Excitability mediates allocation of pre-configured ensembles to a hippocampal engram supporting contextual conditioned threat in mice. Neuron 2024; 112:1487-1497.e6. [PMID: 38447576 PMCID: PMC11065628 DOI: 10.1016/j.neuron.2024.02.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 01/08/2024] [Accepted: 02/05/2024] [Indexed: 03/08/2024]
Abstract
Little is understood about how engrams, sparse groups of neurons that store memories, are formed endogenously. Here, we combined calcium imaging, activity tagging, and optogenetics to examine the role of neuronal excitability and pre-existing functional connectivity on the allocation of mouse cornu ammonis area 1 (CA1) hippocampal neurons to an engram ensemble supporting a contextual threat memory. Engram neurons (high activity during recall or TRAP2-tagged during training) were more active than non-engram neurons 3 h (but not 24 h to 5 days) before training. Consistent with this, optogenetically inhibiting scFLARE2-tagged neurons active in homecage 3 h, but not 24 h, before conditioning disrupted memory retrieval, indicating that neurons with higher pre-training excitability were allocated to the engram. We also observed stable pre-configured functionally connected sub-ensembles of neurons whose activity cycled over days. Sub-ensembles that were more active before training were allocated to the engram, and their functional connectivity increased at training. Therefore, both neuronal excitability and pre-configured functional connectivity mediate allocation to an engram ensemble.
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Affiliation(s)
- Andrew J Mocle
- Program in Neurosciences & Mental Health, Hospital for Sick Children, 555 University Ave., Toronto, ON M5G 1X8, Canada; Department of Physiology, University of Toronto, Toronto, ON M5G 1X8, Canada
| | - Adam I Ramsaran
- Program in Neurosciences & Mental Health, Hospital for Sick Children, 555 University Ave., Toronto, ON M5G 1X8, Canada; Department of Psychology, University of Toronto, Toronto, ON M5G 1X8, Canada
| | - Alexander D Jacob
- Program in Neurosciences & Mental Health, Hospital for Sick Children, 555 University Ave., Toronto, ON M5G 1X8, Canada; Department of Psychology, University of Toronto, Toronto, ON M5G 1X8, Canada
| | - Asim J Rashid
- Program in Neurosciences & Mental Health, Hospital for Sick Children, 555 University Ave., Toronto, ON M5G 1X8, Canada
| | - Alessandro Luchetti
- Program in Neurosciences & Mental Health, Hospital for Sick Children, 555 University Ave., Toronto, ON M5G 1X8, Canada
| | - Lina M Tran
- Program in Neurosciences & Mental Health, Hospital for Sick Children, 555 University Ave., Toronto, ON M5G 1X8, Canada; Department of Physiology, University of Toronto, Toronto, ON M5G 1X8, Canada; Vector Institute, Toronto, ON M5G 1M1, Canada
| | | | - Paul W Frankland
- Program in Neurosciences & Mental Health, Hospital for Sick Children, 555 University Ave., Toronto, ON M5G 1X8, Canada; Department of Physiology, University of Toronto, Toronto, ON M5G 1X8, Canada; Department of Psychology, University of Toronto, Toronto, ON M5G 1X8, Canada; Child & Brain Development Program, Canadian Institute for Advanced Research (CIFAR), Toronto, ON M5G 1M1, Canada
| | - Sheena A Josselyn
- Program in Neurosciences & Mental Health, Hospital for Sick Children, 555 University Ave., Toronto, ON M5G 1X8, Canada; Department of Physiology, University of Toronto, Toronto, ON M5G 1X8, Canada; Department of Psychology, University of Toronto, Toronto, ON M5G 1X8, Canada.
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7
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Lazarov O, Gupta M, Kumar P, Morrissey Z, Phan T. Memory circuits in dementia: The engram, hippocampal neurogenesis and Alzheimer's disease. Prog Neurobiol 2024; 236:102601. [PMID: 38570083 PMCID: PMC11221328 DOI: 10.1016/j.pneurobio.2024.102601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 03/20/2024] [Accepted: 03/22/2024] [Indexed: 04/05/2024]
Abstract
Here, we provide an in-depth consideration of our current understanding of engrams, spanning from molecular to network levels, and hippocampal neurogenesis, in health and Alzheimer's disease (AD). This review highlights novel findings in these emerging research fields and future research directions for novel therapeutic avenues for memory failure in dementia. Engrams, memory in AD, and hippocampal neurogenesis have each been extensively studied. The integration of these topics, however, has been relatively less deliberated, and is the focus of this review. We primarily focus on the dentate gyrus (DG) of the hippocampus, which is a key area of episodic memory formation. Episodic memory is significantly impaired in AD, and is also the site of adult hippocampal neurogenesis. Advancements in technology, especially opto- and chemogenetics, have made sophisticated manipulations of engram cells possible. Furthermore, innovative methods have emerged for monitoring neurons, even specific neuronal populations, in vivo while animals engage in tasks, such as calcium imaging. In vivo calcium imaging contributes to a more comprehensive understanding of engram cells. Critically, studies of the engram in the DG using these technologies have shown the important contribution of hippocampal neurogenesis for memory in both health and AD. Together, the discussion of these topics provides a holistic perspective that motivates questions for future research.
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Affiliation(s)
- Orly Lazarov
- Department of Anatomy and Cell Biology, College of Medicine, The University of Illinois at Chicago, Chicago, IL 60612, USA.
| | - Muskan Gupta
- Department of Anatomy and Cell Biology, College of Medicine, The University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Pavan Kumar
- Department of Anatomy and Cell Biology, College of Medicine, The University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Zachery Morrissey
- Department of Anatomy and Cell Biology, College of Medicine, The University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Trongha Phan
- Department of Anatomy and Cell Biology, College of Medicine, The University of Illinois at Chicago, Chicago, IL 60612, USA
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8
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Sortman BW, Rakela S, Paprotna S, Cerci B, Warren BL. Nucleus accumbens neuronal ensembles vary with cocaine reinforcement in male and female rats. Addict Biol 2024; 29:e13397. [PMID: 38711205 PMCID: PMC11074382 DOI: 10.1111/adb.13397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 03/08/2024] [Accepted: 04/03/2024] [Indexed: 05/08/2024]
Abstract
Neuronal ensembles in the medial prefrontal cortex mediate cocaine self-administration via projections to the nucleus accumbens. We have recently shown that neuronal ensembles in the prelimbic cortex form rapidly to mediate cocaine self-administration. However, the role of neuronal ensembles within the nucleus accumbens in initial cocaine-seeking behaviour remains unknown. Here, we sought to expand the current literature by testing the necessity of the cocaine self-administration ensemble in the nucleus accumbens core (NAcCore) 1 day after male and female rats acquire cocaine self-administration by using the Daun02 inactivation procedure. We found that disrupting the NAcCore ensembles after a no-cocaine reward-seeking test increased subsequent cocaine seeking, while disrupting NAcCore ensembles following a cocaine self-administration session decreased subsequent cocaine seeking. We then characterized neuronal cell type in the NAcCore using RNAscope in situ hybridization. In the no-cocaine session, we saw reduced dopamine D1 type neuronal activation, while in the cocaine self-administration session, we found preferential dopamine D1 type neuronal activity in the NAcCore.
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Affiliation(s)
- Bo W. Sortman
- Department of PharmacodynamicsUniversity of FloridaGainesvilleFloridaUSA
| | - Samantha Rakela
- Department of PharmacodynamicsUniversity of FloridaGainesvilleFloridaUSA
| | - Sarah Paprotna
- Department of PharmacodynamicsUniversity of FloridaGainesvilleFloridaUSA
| | - Berk Cerci
- Department of PharmacodynamicsUniversity of FloridaGainesvilleFloridaUSA
| | - Brandon L. Warren
- Department of PharmacodynamicsUniversity of FloridaGainesvilleFloridaUSA
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9
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Nasretdinov A, Jappy D, Vazetdinova A, Valiullina-Rakhmatullina F, Rozov A. Acute stress modulates hippocampal to entorhinal cortex communication. Front Cell Neurosci 2023; 17:1327909. [PMID: 38145281 PMCID: PMC10740169 DOI: 10.3389/fncel.2023.1327909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 11/24/2023] [Indexed: 12/26/2023] Open
Abstract
Feed-forward inhibition is vital in the transfer and processing of synaptic information within the hippocampal-entorhinal loop by controlling the strength and direction of excitation flow between different neuronal populations and individual neurons. While the cellular targets in the hippocampus that receive excitatory inputs from the entorhinal cortex have been well studied, and the role of feedforward inhibitory neurons has been attributed to neurogliafom cells, the cortical interneurons providing feed-forward control over receiving layer V in the entorhinal cortex remain unknown. We used sharp-wave ripple oscillations as a natural excitatory stimulus of the entorhinal cortex, driven by the hippocampus, to study the function of synaptic interactions between neurons in the deep layers of the entorhinal cortex. We discovered that CB1R-expressing interneurons in the deep layers of the entorhinal cortex constitute the major relay station that translates hippocampal excitation into efficient inhibition of cortical pyramidal cells. The impact of inhibition provided by these interneurons is under strong endocannabinoid control and can be drastically reduced either by enhanced activity of postsynaptic targets or by stress-induced elevation of cannabinoids.
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Affiliation(s)
- Azat Nasretdinov
- Laboratory of Neurobiology, Kazan Federal University, Kazan, Russia
| | - David Jappy
- Federal Center of Brain Research and Neurotechnologies, Moscow, Russia
- Institute of Neuroscience, Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia
| | - Alina Vazetdinova
- Laboratory of Neurobiology, Kazan Federal University, Kazan, Russia
- Federal Center of Brain Research and Neurotechnologies, Moscow, Russia
| | - Fliza Valiullina-Rakhmatullina
- Laboratory of Neurobiology, Kazan Federal University, Kazan, Russia
- Federal Center of Brain Research and Neurotechnologies, Moscow, Russia
| | - Andrei Rozov
- Federal Center of Brain Research and Neurotechnologies, Moscow, Russia
- Department of Physiology and Pathophysiology, Heidelberg University, Heidelberg, Germany
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10
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Hijazi S, Smit AB, van Kesteren RE. Fast-spiking parvalbumin-positive interneurons in brain physiology and Alzheimer's disease. Mol Psychiatry 2023; 28:4954-4967. [PMID: 37419975 PMCID: PMC11041664 DOI: 10.1038/s41380-023-02168-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 06/26/2023] [Accepted: 06/26/2023] [Indexed: 07/09/2023]
Abstract
Fast-spiking parvalbumin (PV) interneurons are inhibitory interneurons with unique morphological and functional properties that allow them to precisely control local circuitry, brain networks and memory processing. Since the discovery in 1987 that PV is expressed in a subset of fast-spiking GABAergic inhibitory neurons, our knowledge of the complex molecular and physiological properties of these cells has been expanding. In this review, we highlight the specific properties of PV neurons that allow them to fire at high frequency and with high reliability, enabling them to control network oscillations and shape the encoding, consolidation and retrieval of memories. We next discuss multiple studies reporting PV neuron impairment as a critical step in neuronal network dysfunction and cognitive decline in mouse models of Alzheimer's disease (AD). Finally, we propose potential mechanisms underlying PV neuron dysfunction in AD and we argue that early changes in PV neuron activity could be a causal step in AD-associated network and memory impairment and a significant contributor to disease pathogenesis.
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Affiliation(s)
- Sara Hijazi
- Department of Pharmacology, University of Oxford, Oxford, OX1 3QT, UK
| | - August B Smit
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, 1081 HV, Amsterdam, The Netherlands
| | - Ronald E van Kesteren
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, 1081 HV, Amsterdam, The Netherlands.
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11
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Chen APF, Chen L, Shi KW, Cheng E, Ge S, Xiong Q. Nigrostriatal dopamine modulates the striatal-amygdala pathway in auditory fear conditioning. Nat Commun 2023; 14:7231. [PMID: 37945595 PMCID: PMC10636191 DOI: 10.1038/s41467-023-43066-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 10/31/2023] [Indexed: 11/12/2023] Open
Abstract
The auditory striatum, a sensory portion of the dorsal striatum, plays an essential role in learning and memory. In contrast to its roles and underlying mechanisms in operant conditioning, however, little is known about its contribution to classical auditory fear conditioning. Here, we reveal the function of the auditory striatum in auditory-conditioned fear memory. We find that optogenetically inhibiting auditory striatal neurons impairs fear memory formation, which is mediated through the striatal-amygdala pathway. Using calcium imaging in behaving mice, we find that auditory striatal neuronal responses to conditioned tones potentiate across memory acquisition and expression. Furthermore, nigrostriatal dopaminergic projections plays an important role in modulating conditioning-induced striatal potentiation. Together, these findings demonstrate the existence of a nigro-striatal-amygdala circuit for conditioned fear memory formation and expression.
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Affiliation(s)
- Allen P F Chen
- Department of Neurobiology and Behavior, SUNY Stony Brook, Stony Brook, NY, 11794, USA
- Medical Scientist Training Program, Renaissance School of Medicine at SUNY Stony Brook, Stony Brook, NY, 11794, USA
| | - Lu Chen
- Department of Neurobiology and Behavior, SUNY Stony Brook, Stony Brook, NY, 11794, USA
| | - Kaiyo W Shi
- Department of Neurobiology and Behavior, SUNY Stony Brook, Stony Brook, NY, 11794, USA
| | - Eileen Cheng
- Department of Neurobiology and Behavior, SUNY Stony Brook, Stony Brook, NY, 11794, USA
- Department of Physiology and Biophysics, SUNY Stony Brook, Stony Brook, NY, 11794, USA
| | - Shaoyu Ge
- Department of Neurobiology and Behavior, SUNY Stony Brook, Stony Brook, NY, 11794, USA
| | - Qiaojie Xiong
- Department of Neurobiology and Behavior, SUNY Stony Brook, Stony Brook, NY, 11794, USA.
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12
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Lee H, Kaang BK. How engram mediates learning, extinction, and relapse. Curr Opin Neurobiol 2023; 81:102723. [PMID: 37030026 DOI: 10.1016/j.conb.2023.102723] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 03/10/2023] [Accepted: 03/10/2023] [Indexed: 04/08/2023]
Abstract
Fear learning ensures survival through an expression of certain behavior as a conditioned fear response. Fear memory is processed and stored in a fear memory circuit, including the amygdala, hippocampus, and prefrontal cortex. A gradual decrease in conditioned fear response can be induced by fear extinction, which is mediated through the weakening of the original fear memory traces and the newly formed inhibition of those traces. Fear memory can also recover after extinction, which shows flexible control of the fear memory state. Here, we demonstrate how fear engram, which is a physical substrate of fear memory, changes during fear extinction and relapse by reviewing recent studies regarding engram.
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Affiliation(s)
- Hoonwon Lee
- School of Biological Sciences, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, South Korea
| | - Bong-Kiun Kaang
- School of Biological Sciences, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, South Korea.
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13
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Brosens N, Lesuis SL, Bassie I, Reyes L, Gajadien P, Lucassen PJ, Krugers HJ. Elevated corticosterone after fear learning impairs remote auditory memory retrieval and alters brain network connectivity. Learn Mem 2023; 30:125-132. [PMID: 37487708 PMCID: PMC10519398 DOI: 10.1101/lm.053836.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Accepted: 06/23/2023] [Indexed: 07/26/2023]
Abstract
Glucocorticoids are potent memory modulators that can modify behavior in an adaptive or maladaptive manner. Elevated glucocorticoid levels after learning promote memory consolidation at recent time points, but their effects on remote time points are not well established. Here we set out to assess whether corticosterone (CORT) given after learning modifies remote fear memory. To that end, mice were exposed to a mild auditory fear conditioning paradigm followed by a single 2 mg/kg CORT injection, and after 28 d, auditory memory was assessed. Neuronal activation was investigated using immunohistochemistry for the immediate early gene c-Fos, and coactivation of brain regions was determined using a correlation matrix analysis. CORT-treated mice displayed significantly less remote auditory memory retrieval. While the net activity of studied brain regions was similar compared with the control condition, CORT-induced remote memory impairment was associated with altered correlated activity between brain regions. Specifically, connectivity of the lateral amygdala with the basal amygdala and the dorsal dentate gyrus was significantly reduced in CORT-treated mice, suggesting disrupted network connectivity that may underlie diminished remote memory retrieval. Elucidating the pathways underlying these effects could help provide mechanistic insight into the effects of stress on memory and possibly provide therapeutic targets for psychopathology.
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Affiliation(s)
- Niek Brosens
- Brain Plasticity Group, Swammerdam Institute for Life Sciences (SILS)-Cognitive and Systems Neuroscience (CNS), University of Amsterdam, Amsterdam 1098 XH, the Netherlands
| | - Sylvie L Lesuis
- Program in Neurosciences and Mental Health, Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada
| | - Ilse Bassie
- Brain Plasticity Group, Swammerdam Institute for Life Sciences (SILS)-Cognitive and Systems Neuroscience (CNS), University of Amsterdam, Amsterdam 1098 XH, the Netherlands
| | - Lara Reyes
- Brain Plasticity Group, Swammerdam Institute for Life Sciences (SILS)-Cognitive and Systems Neuroscience (CNS), University of Amsterdam, Amsterdam 1098 XH, the Netherlands
| | - Priya Gajadien
- Brain Plasticity Group, Swammerdam Institute for Life Sciences (SILS)-Cognitive and Systems Neuroscience (CNS), University of Amsterdam, Amsterdam 1098 XH, the Netherlands
| | - Paul J Lucassen
- Brain Plasticity Group, Swammerdam Institute for Life Sciences (SILS)-Cognitive and Systems Neuroscience (CNS), University of Amsterdam, Amsterdam 1098 XH, the Netherlands
| | - Harm J Krugers
- Brain Plasticity Group, Swammerdam Institute for Life Sciences (SILS)-Cognitive and Systems Neuroscience (CNS), University of Amsterdam, Amsterdam 1098 XH, the Netherlands
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14
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Jung JH, Wang Y, Mocle AJ, Zhang T, Köhler S, Frankland PW, Josselyn SA. Examining the engram encoding specificity hypothesis in mice. Neuron 2023; 111:1830-1845.e5. [PMID: 36990091 DOI: 10.1016/j.neuron.2023.03.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 02/07/2023] [Accepted: 03/06/2023] [Indexed: 03/30/2023]
Abstract
According to the encoding specificity hypothesis, memory is best recalled by retrieval cues that overlap with training cues. Human studies generally support this hypothesis. However, memories are thought to be stored in neuronal ensembles (engrams), and retrieval cues are thought to reactivate neurons in an engram to induce memory recall. Here, we visualized engrams in mice to test whether retrieval cues that overlap with training cues produce maximal memory recall via high engram reactivation (engram encoding specificity hypothesis). Using variations of cued threat conditioning (pairing conditioned stimulus [CS] with footshock), we manipulated encoding and retrieval conditions along multiple domains, including pharmacological state, external sensory cue, and internal optogenetic cue. Maximal engram reactivation and memory recall occurred when retrieval conditions closely matched training conditions. These findings provide a biological basis for the encoding specificity hypothesis and highlight the important interaction between stored information (engram) and cues available at memory retrieval (ecphory).
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Affiliation(s)
- Jung Hoon Jung
- Program in Neurosciences & Mental Health, Hospital for Sick Children, 555 University Ave., Toronto, ON M5G 1X8, Canada
| | - Ying Wang
- Program in Neurosciences & Mental Health, Hospital for Sick Children, 555 University Ave., Toronto, ON M5G 1X8, Canada; Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Andrew J Mocle
- Program in Neurosciences & Mental Health, Hospital for Sick Children, 555 University Ave., Toronto, ON M5G 1X8, Canada; Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Tao Zhang
- Program in Neurosciences & Mental Health, Hospital for Sick Children, 555 University Ave., Toronto, ON M5G 1X8, Canada
| | - Stefan Köhler
- Department of Psychology, University of Western Ontario, London, ON N6A 5C2, Canada; The Brain and Mind Institute, University of Western Ontario, London, ON N6A 3K7, Canada
| | - Paul W Frankland
- Program in Neurosciences & Mental Health, Hospital for Sick Children, 555 University Ave., Toronto, ON M5G 1X8, Canada; Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada; Department of Psychology, University of Toronto, Toronto, ON M5S 3G3, Canada; Child & Brain Development Program, Canadian Institute for Advanced Research (CIFAR), Toronto, ON M5G 1M1, Canada
| | - Sheena A Josselyn
- Program in Neurosciences & Mental Health, Hospital for Sick Children, 555 University Ave., Toronto, ON M5G 1X8, Canada; Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada; Department of Psychology, University of Toronto, Toronto, ON M5S 3G3, Canada.
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15
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Ramsaran AI, Wang Y, Golbabaei A, Aleshin S, de Snoo ML, Yeung BRA, Rashid AJ, Awasthi A, Lau J, Tran LM, Ko SY, Abegg A, Duan LC, McKenzie C, Gallucci J, Ahmed M, Kaushik R, Dityatev A, Josselyn SA, Frankland PW. A shift in the mechanisms controlling hippocampal engram formation during brain maturation. Science 2023; 380:543-551. [PMID: 37141366 DOI: 10.1126/science.ade6530] [Citation(s) in RCA: 28] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The ability to form precise, episodic memories develops with age, with young children only able to form gist-like memories that lack precision. The cellular and molecular events in the developing hippocampus that underlie the emergence of precise, episodic-like memory are unclear. In mice, the absence of a competitive neuronal engram allocation process in the immature hippocampus precluded the formation of sparse engrams and precise memories until the fourth postnatal week, when inhibitory circuits in the hippocampus mature. This age-dependent shift in precision of episodic-like memories involved the functional maturation of parvalbumin-expressing interneurons in subfield CA1 through assembly of extracellular perineuronal nets, which is necessary and sufficient for the onset of competitive neuronal allocation, sparse engram formation, and memory precision.
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Affiliation(s)
- Adam I Ramsaran
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Psychology, University of Toronto, Toronto, Ontario, Canada
| | - Ying Wang
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Ali Golbabaei
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Stepan Aleshin
- Molecular Neuroplasticity, German Center for Neurodegenerative Diseases, Magdeburg, Germany
| | - Mitchell L de Snoo
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Bi-Ru Amy Yeung
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Asim J Rashid
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Ankit Awasthi
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Jocelyn Lau
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Lina M Tran
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
- Vector Institute, Toronto, Ontario, Canada
| | - Sangyoon Y Ko
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Andrin Abegg
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Biology, ETH Zürich, Zürich, Switzerland
| | - Lana Chunan Duan
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Cory McKenzie
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Psychology, University of Toronto, Toronto, Ontario, Canada
| | - Julia Gallucci
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Moriam Ahmed
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Rahul Kaushik
- Molecular Neuroplasticity, German Center for Neurodegenerative Diseases, Magdeburg, Germany
- Center for Behavioral Brain Sciences, Magdeburg, Germany
| | - Alexander Dityatev
- Molecular Neuroplasticity, German Center for Neurodegenerative Diseases, Magdeburg, Germany
- Center for Behavioral Brain Sciences, Magdeburg, Germany
- Medical Faculty, Otto von Guericke University, Magdeburg, Germany
| | - Sheena A Josselyn
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Psychology, University of Toronto, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
- Brain, Mind, & Consciousness Program, Canadian Institute for Advanced Research, Toronto, Ontario, Canada
| | - Paul W Frankland
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Psychology, University of Toronto, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
- Child & Brain Development Program, Canadian Institute for Advanced Research, Toronto, Ontario, Canada
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16
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Aery Jones EA, Giocomo LM. Neural ensembles in navigation: From single cells to population codes. Curr Opin Neurobiol 2023; 78:102665. [PMID: 36542882 PMCID: PMC9845194 DOI: 10.1016/j.conb.2022.102665] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 10/27/2022] [Accepted: 11/21/2022] [Indexed: 12/23/2022]
Abstract
The brain can represent behaviorally relevant information through the firing of individual neurons as well as the coordinated firing of ensembles of neurons. Neurons in the hippocampus and associated cortical regions participate in a variety of types of ensembles to support navigation. These ensemble types include single cell codes, population codes, time-compressed sequences, behavioral sequences, and engrams. We present the physiological basis and behavioral relevance of ensemble firing. We discuss how these traditional definitions of ensembles can constrain or expand potential analyses due to the underlying assumptions and abstractions made. We highlight how coding can change at the ensemble level while underlying single cell codes remain intact. Finally, we present how ensemble definitions could be broadened to better understand the full complexity of the brain.
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Affiliation(s)
- Emily A Aery Jones
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA, 94305, USA.
| | - Lisa M Giocomo
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA, 94305, USA.
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17
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Fernández-Blanco Á, Zamora-Moratalla A, Sabariego-Navarro M, Dierssen M. Defective engram allocation contributes to impaired fear memory performance in Down syndrome. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.11.523460. [PMID: 36711850 PMCID: PMC9882045 DOI: 10.1101/2023.01.11.523460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Down syndrome (DS) is the most common genetic form of intellectual disability (ID). The cellular and molecular mechanisms contributing to ID in DS are not completely understood. Recent evidence indicates that a given memory is encoded by sparsely distributed neurons, highly activated during learning, the engram cells. Intriguingly, mechanisms that are of paramount importance for engram formation are impaired in DS. Here we explored engram formation in a DS mouse model, the Ts65Dn and we found a reduced number of engram cells in the dentate gyrus (DG), suggesting reduced neuronal allocation to engrams. We also show that trisomic engram cells present reduced number of mature spines than WT engram cells and their excitability is not enhanced during memory recall. In fact, activation of engram cells using a chemogenetic approach does not recover memory deficits in Ts65Dn. Altogether, our findings suggest that perturbations in engram neurons may play a significant role in memory alterations in DS.
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18
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Kolatt Chandran S, Yiannakas A, Kayyal H, Salalha R, Cruciani F, Mizrahi L, Khamaisy M, Stern S, Rosenblum K. Intrinsic Excitability in Layer IV-VI Anterior Insula to Basolateral Amygdala Projection Neurons Correlates with the Confidence of Taste Valence Encoding. eNeuro 2023; 10:ENEURO.0302-22.2022. [PMID: 36635250 PMCID: PMC9850927 DOI: 10.1523/eneuro.0302-22.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Revised: 09/01/2022] [Accepted: 09/11/2022] [Indexed: 12/14/2022] Open
Abstract
Avoiding potentially harmful, and consuming safe food is crucial for the survival of living organisms. However, the perceived valence of sensory information can change following conflicting experiences. Pleasurability and aversiveness are two crucial parameters defining the perceived valence of a taste and can be impacted by novelty. Importantly, the ability of a given taste to serve as the conditioned stimulus (CS) in conditioned taste aversion (CTA) is dependent on its valence. Activity in anterior insula (aIC) Layer IV-VI pyramidal neurons projecting to the basolateral amygdala (BLA) is correlated with and necessary for CTA learning and retrieval, as well as the expression of neophobia toward novel tastants, but not learning taste familiarity. Yet, the cellular mechanisms underlying the updating of taste valence representation in this specific pathway are poorly understood. Here, using retrograde viral tracing and whole-cell patch-clamp electrophysiology in trained mice, we demonstrate that the intrinsic properties of deep-lying Layer IV-VI, but not superficial Layer I-III aIC-BLA neurons, are differentially modulated by both novelty and valence, reflecting the subjective predictability of taste valence arising from prior experience. These correlative changes in the profile of intrinsic properties of LIV-VI aIC-BLA neurons were detectable following both simple taste experiences, as well as following memory retrieval, extinction learning, and reinstatement.
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Affiliation(s)
| | - Adonis Yiannakas
- Sagol Department of Neurobiology, University of Haifa, Abba Khoushy Ave 199, Haifa, 3498838, Israel
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bühlstrasse 28, 3012 Bern, Switzerland
| | - Haneen Kayyal
- Sagol Department of Neurobiology, University of Haifa, Abba Khoushy Ave 199, Haifa, 3498838, Israel
| | - Randa Salalha
- Sagol Department of Neurobiology, University of Haifa, Abba Khoushy Ave 199, Haifa, 3498838, Israel
| | - Federica Cruciani
- Sagol Department of Neurobiology, University of Haifa, Abba Khoushy Ave 199, Haifa, 3498838, Israel
| | - Liron Mizrahi
- Sagol Department of Neurobiology, University of Haifa, Abba Khoushy Ave 199, Haifa, 3498838, Israel
| | - Mohammad Khamaisy
- Sagol Department of Neurobiology, University of Haifa, Abba Khoushy Ave 199, Haifa, 3498838, Israel
| | - Shani Stern
- Sagol Department of Neurobiology, University of Haifa, Abba Khoushy Ave 199, Haifa, 3498838, Israel
| | - Kobi Rosenblum
- Sagol Department of Neurobiology, University of Haifa, Abba Khoushy Ave 199, Haifa, 3498838, Israel
- Center for Gene Manipulation in the Brain, University of Haifa, Haifa, Israel
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19
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Singh S, Topolnik L. Inhibitory circuits in fear memory and fear-related disorders. Front Neural Circuits 2023; 17:1122314. [PMID: 37035504 PMCID: PMC10076544 DOI: 10.3389/fncir.2023.1122314] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 02/17/2023] [Indexed: 04/11/2023] Open
Abstract
Fear learning and memory rely on dynamic interactions between the excitatory and inhibitory neuronal populations that make up the prefrontal cortical, amygdala, and hippocampal circuits. Whereas inhibition of excitatory principal cells (PCs) by GABAergic neurons restrains their excitation, inhibition of GABAergic neurons promotes the excitation of PCs through a process called disinhibition. Specifically, GABAergic interneurons that express parvalbumin (PV+) and somatostatin (SOM+) provide inhibition to different subcellular domains of PCs, whereas those that express the vasoactive intestinal polypeptide (VIP+) facilitate disinhibition of PCs by inhibiting PV+ and SOM+ interneurons. Importantly, although the main connectivity motifs and the underlying network functions of PV+, SOM+, and VIP+ interneurons are replicated across cortical and limbic areas, these inhibitory populations play region-specific roles in fear learning and memory. Here, we provide an overview of the fear processing in the amygdala, hippocampus, and prefrontal cortex based on the evidence obtained in human and animal studies. Moreover, focusing on recent findings obtained using genetically defined imaging and intervention strategies, we discuss the population-specific functions of PV+, SOM+, and VIP+ interneurons in fear circuits. Last, we review current insights that integrate the region-specific inhibitory and disinhibitory network patterns into fear memory acquisition and fear-related disorders.
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Affiliation(s)
- Sanjay Singh
- Department of Biochemistry, Microbiology and Bio-informatics, Laval University, Quebec City, QC, Canada
- Neuroscience Axis, CRCHUQ, Laval University, Quebec City, QC, Canada
| | - Lisa Topolnik
- Department of Biochemistry, Microbiology and Bio-informatics, Laval University, Quebec City, QC, Canada
- Neuroscience Axis, CRCHUQ, Laval University, Quebec City, QC, Canada
- *Correspondence: Lisa Topolnik
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20
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Scott DN, Frank MJ. Adaptive control of synaptic plasticity integrates micro- and macroscopic network function. Neuropsychopharmacology 2023; 48:121-144. [PMID: 36038780 PMCID: PMC9700774 DOI: 10.1038/s41386-022-01374-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 06/23/2022] [Accepted: 06/24/2022] [Indexed: 11/09/2022]
Abstract
Synaptic plasticity configures interactions between neurons and is therefore likely to be a primary driver of behavioral learning and development. How this microscopic-macroscopic interaction occurs is poorly understood, as researchers frequently examine models within particular ranges of abstraction and scale. Computational neuroscience and machine learning models offer theoretically powerful analyses of plasticity in neural networks, but results are often siloed and only coarsely linked to biology. In this review, we examine connections between these areas, asking how network computations change as a function of diverse features of plasticity and vice versa. We review how plasticity can be controlled at synapses by calcium dynamics and neuromodulatory signals, the manifestation of these changes in networks, and their impacts in specialized circuits. We conclude that metaplasticity-defined broadly as the adaptive control of plasticity-forges connections across scales by governing what groups of synapses can and can't learn about, when, and to what ends. The metaplasticity we discuss acts by co-opting Hebbian mechanisms, shifting network properties, and routing activity within and across brain systems. Asking how these operations can go awry should also be useful for understanding pathology, which we address in the context of autism, schizophrenia and Parkinson's disease.
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Affiliation(s)
- Daniel N Scott
- Cognitive Linguistic, and Psychological Sciences, Brown University, Providence, RI, USA.
- Carney Institute for Brain Science, Brown University, Providence, RI, USA.
| | - Michael J Frank
- Cognitive Linguistic, and Psychological Sciences, Brown University, Providence, RI, USA.
- Carney Institute for Brain Science, Brown University, Providence, RI, USA.
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21
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Yang J, Serrano P, Yin X, Sun X, Lin Y, Chen SX. Functionally distinct NPAS4-expressing somatostatin interneuron ensembles critical for motor skill learning. Neuron 2022; 110:3339-3355.e8. [PMID: 36099920 DOI: 10.1016/j.neuron.2022.08.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 07/01/2022] [Accepted: 08/15/2022] [Indexed: 10/14/2022]
Abstract
During motor learning, dendritic spines on pyramidal neurons (PNs) in the primary motor cortex (M1) undergo reorganization. Intriguingly, the inhibition from local somatostatin-expressing inhibitory neurons (SST-INs) plays an important role in regulating the PN plasticity and thus new motor skill acquisition. However, the molecular mechanisms underlying this process remain unclear. Here, we identified that the early-response transcription factor, NPAS4, is selectively expressed in SST-INs during motor learning. By utilizing in vivo two-photon imaging in mice, we found that cell-type-specific deletion of Npas4 in M1 disrupted learning-induced spine reorganization among PNs and impaired motor learning. In addition, NPAS4-expressing SST-INs exhibited lower neuronal activity during task-related movements, and chemogenetically increasing the activity of NPAS4-expressing ensembles was sufficient to mimic the effects of Npas4 deletion. Together, our results reveal an instructive role of NPAS4-expressing SST-INs in modulating the inhibition to downstream task-related PNs to allow proper spine reorganization that is critical for motor learning.
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Affiliation(s)
- Jungwoo Yang
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Pablo Serrano
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Xuming Yin
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Xiaochen Sun
- Department of Psychiatry and Behavioral Sciences, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Yingxi Lin
- Department of Psychiatry and Behavioral Sciences, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Simon X Chen
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada; Brain and Mind Research Institute, University of Ottawa, Ottawa, ON K1H 8M5, Canada; Center for Neural Dynamics, University of Ottawa, Ottawa, ON K1H 8M5, Canada.
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22
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Jeanneteau F, Coutellier L. The glucocorticoid footprint on the memory engram. CURRENT OPINION IN ENDOCRINE AND METABOLIC RESEARCH 2022; 25:100378. [PMID: 38486965 PMCID: PMC10938917 DOI: 10.1016/j.coemr.2022.100378] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/17/2024]
Abstract
The complexity of the classical inverted U-shaped relationship between cortisol levels and responses transposable to stress reactivity has led to an incomplete understanding of the mechanisms enabling healthy and toxic effects of stress on brain and behavior. A clearer, more detailed, picture of those relationships can be obtained by integrating cortisol effects on large-scale brain networks, in particular, by focusing on neural network configurations from the perspective of inhibition and excitation. A unifying view of Semon and Hebb's theories of cellular memory links the biophysical and metabolic changes in neuronal ensembles to the strengthening of collective synapses. In that sense, the neuronal capacity to record, store, and retrieve information directly relates to the adaptive capacity of its connectivity and metabolic reserves. Here, we use task-activated cell ensembles or simply engram cells as an example to demonstrate that the adaptive behavioral responses to stress result from collective synapse strength within and across networks of interneurons and excitatory ones.
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Affiliation(s)
- Freddy Jeanneteau
- Institut de Génomique Fonctionnelle, University of Montpellier, INSERM, CNRS, Montpellier, France
| | - Laurence Coutellier
- Departments of Psychology and Neuroscience, Ohio State University, Columbus, USA
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23
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Interrogating structural plasticity among synaptic engrams. Curr Opin Neurobiol 2022; 75:102552. [DOI: 10.1016/j.conb.2022.102552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 04/08/2022] [Accepted: 04/13/2022] [Indexed: 11/21/2022]
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24
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Rienecker KDA, Poston RG, Segales JS, Finholm IW, Sono MH, Munteanu SJ, Ghaninejad-Esfahani M, Rejepova A, Tejeda-Garibay S, Wickman K, Marron Fernandez de Velasco E, Thayer SA, Saha RN. Mild membrane depolarization in neurons induces immediate early gene transcription and acutely subdues responses to successive stimulus. J Biol Chem 2022; 298:102278. [PMID: 35863435 PMCID: PMC9396413 DOI: 10.1016/j.jbc.2022.102278] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Revised: 07/12/2022] [Accepted: 07/13/2022] [Indexed: 11/22/2022] Open
Abstract
Immediate early genes (IEGs) are transcribed in response to neuronal activity from sensory stimulation during multiple adaptive processes in the brain. The transcriptional profile of IEGs is indicative of the duration of neuronal activity, but its sensitivity to the strength of depolarization remains unknown. Also unknown is whether activity history of graded potential changes influence future neuronal activity. In this work with dissociated rat cortical neurons, we found that mild depolarization—mediated by elevated extracellular potassium (K+)—induces a wide array of rapid IEGs and transiently depresses transcriptional and signaling responses to a successive stimulus. This latter effect was independent of de novo transcription, translation, and signaling via calcineurin or mitogen-activated protein kinase. Furthermore, as measured by multiple electrode arrays and calcium imaging, mild depolarization acutely subdues subsequent spontaneous and bicuculline-evoked activity via calcium- and N-methyl-d-aspartate receptor–dependent mechanisms. Collectively, this work suggests that a recent history of graded potential changes acutely depress neuronal intrinsic properties and subsequent responses. Such effects may have several potential downstream implications, including reducing signal-to-noise ratio during synaptic plasticity processes.
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Affiliation(s)
- Kira D A Rienecker
- Molecular and Cell Biology Department, School of Natural Sciences, University of California, Merced, 5200 North Lake Road, Merced, California, USA, 95343
| | - Robert G Poston
- Molecular and Cell Biology Department, School of Natural Sciences, University of California, Merced, 5200 North Lake Road, Merced, California, USA, 95343
| | - Joshua S Segales
- Molecular and Cell Biology Department, School of Natural Sciences, University of California, Merced, 5200 North Lake Road, Merced, California, USA, 95343
| | - Isabelle W Finholm
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, MN, 55455, USA
| | - Morgan H Sono
- Molecular and Cell Biology Department, School of Natural Sciences, University of California, Merced, 5200 North Lake Road, Merced, California, USA, 95343
| | - Sorina J Munteanu
- Molecular and Cell Biology Department, School of Natural Sciences, University of California, Merced, 5200 North Lake Road, Merced, California, USA, 95343
| | - Mina Ghaninejad-Esfahani
- Molecular and Cell Biology Department, School of Natural Sciences, University of California, Merced, 5200 North Lake Road, Merced, California, USA, 95343
| | - Ayna Rejepova
- Molecular and Cell Biology Department, School of Natural Sciences, University of California, Merced, 5200 North Lake Road, Merced, California, USA, 95343
| | - Susana Tejeda-Garibay
- Molecular and Cell Biology Department, School of Natural Sciences, University of California, Merced, 5200 North Lake Road, Merced, California, USA, 95343
| | - Kevin Wickman
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, MN, 55455, USA
| | | | - Stanley A Thayer
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, MN, 55455, USA
| | - Ramendra N Saha
- Molecular and Cell Biology Department, School of Natural Sciences, University of California, Merced, 5200 North Lake Road, Merced, California, USA, 95343.
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25
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The role of inhibitory circuits in hippocampal memory processing. Nat Rev Neurosci 2022; 23:476-492. [DOI: 10.1038/s41583-022-00599-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/22/2022] [Indexed: 11/08/2022]
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26
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Liu J, Totty MS, Melissari L, Bayer H, Maren S. Convergent Coding of Recent and Remote Fear Memory in the Basolateral Amygdala. Biol Psychiatry 2022; 91:832-840. [PMID: 35246314 PMCID: PMC9018498 DOI: 10.1016/j.biopsych.2021.12.018] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 12/30/2021] [Accepted: 12/30/2021] [Indexed: 11/02/2022]
Abstract
BACKGROUND In both rodents and humans, the basolateral amygdala (BLA) is essential for encoding and retrieving conditioned fear memories. Although the BLA is a putative storage site for these memories, recent evidence suggests that they become independent of the BLA with the passage of time. METHODS We systematically examined the role for the BLA in the retrieval of recent (1 day) and remote (2 weeks) fear memory using optogenetic, electrophysiological, and calcium imaging methods in male and female Long-Evans rats. Critically, we used a behavioral design that permits within-subjects comparison of recent and remote memory at the same time point; freezing behavior served as the index of learned fear. RESULTS We found that BLA c-Fos expression was similar after the retrieval of recent or remote fear memories. Extracellular single-unit recordings in awake, behaving animals revealed that single BLA neurons exhibit robust increases in spike firing to both recent and remote conditioned stimuli. Fiber photometry recordings revealed that these patterns of activity emerge from principal neurons. Consistent with these results, optogenetic inhibition of BLA principal neurons impaired conditioned freezing to both recent and remote conditioned stimuli. There were no sex differences in any of the measures or manipulations. CONCLUSIONS These data reveal that BLA neurons encode both recent and remote fear memories, suggesting substantial overlap in the allocation of temporally distinct events. This may underlie the broad generalization of fear memories across both space and time. Ultimately, these results provide evidence that the BLA is a long-term storage site for emotional memories.
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Affiliation(s)
| | | | | | | | - Stephen Maren
- Department of Psychological and Brain Sciences and Institute for Neuroscience, Texas A&M University, College Station, Texas.
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27
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Tomé DF, Sadeh S, Clopath C. Coordinated hippocampal-thalamic-cortical communication crucial for engram dynamics underneath systems consolidation. Nat Commun 2022; 13:840. [PMID: 35149680 PMCID: PMC8837777 DOI: 10.1038/s41467-022-28339-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2021] [Accepted: 01/13/2022] [Indexed: 11/09/2022] Open
Abstract
Systems consolidation refers to the time-dependent reorganization of memory representations or engrams across brain regions. Despite recent advancements in unravelling this process, the exact mechanisms behind engram dynamics and the role of associated pathways remain largely unknown. Here we propose a biologically-plausible computational model to address this knowledge gap. By coordinating synaptic plasticity timescales and incorporating a hippocampus-thalamus-cortex circuit, our model is able to couple engram reactivations across these regions and thereby reproduce key dynamics of cortical and hippocampal engram cells along with their interdependencies. Decoupling hippocampal-thalamic-cortical activity disrupts systems consolidation. Critically, our model yields testable predictions regarding hippocampal and thalamic engram cells, inhibitory engrams, thalamic inhibitory input, and the effect of thalamocortical synaptic coupling on retrograde amnesia induced by hippocampal lesions. Overall, our results suggest that systems consolidation emerges from coupled reactivations of engram cells in distributed brain regions enabled by coordinated synaptic plasticity timescales in multisynaptic subcortical-cortical circuits.
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Affiliation(s)
| | - Sadra Sadeh
- Department of Bioengineering, Imperial College London, London, UK
| | - Claudia Clopath
- Department of Bioengineering, Imperial College London, London, UK.
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28
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Tzilivaki A, Kastellakis G, Schmitz D, Poirazi P. GABAergic Interneurons with Nonlinear Dendrites: From Neuronal Computations to Memory Engrams. Neuroscience 2021; 489:34-43. [PMID: 34843894 DOI: 10.1016/j.neuroscience.2021.11.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Revised: 11/08/2021] [Accepted: 11/22/2021] [Indexed: 10/19/2022]
Abstract
GABAergic interneurons (INs) are a highly diverse class of neurons in the mammalian brain with a critical role in orchestrating multiple cognitive functions and maintaining the balance of excitation/inhibition across neuronal circuitries. In this perspective, we discuss recent findings regarding the ability of some IN subtypes to integrate incoming inputs in nonlinear ways within their dendritic branches. These recently discovered features may endow the specific INs with advanced computing capabilities, whose breadth and functional contributions remain an open question. Along these lines, we discuss theoretical and experimental evidence regarding the potential role of nonlinear IN dendrites in advancing single neuron computations and contributing to memory formation.
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Affiliation(s)
- Alexandra Tzilivaki
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Charitéplatz 1, 10117 Berlin, Germany; Einstein Center for Neurosciences Berlin, Charitéplatz 1, 10117 Berlin, Germany; Neurocure Cluster of Excellence, Charitéplatz 1, 10117 Berlin, Germany; Foundation for Research and Technology Hellas, Institute of Molecular Biology and Biotechnology, Greece
| | - George Kastellakis
- Foundation for Research and Technology Hellas, Institute of Molecular Biology and Biotechnology, Greece
| | - Dietmar Schmitz
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Charitéplatz 1, 10117 Berlin, Germany; Einstein Center for Neurosciences Berlin, Charitéplatz 1, 10117 Berlin, Germany; Neurocure Cluster of Excellence, Charitéplatz 1, 10117 Berlin, Germany
| | - Panayiota Poirazi
- Foundation for Research and Technology Hellas, Institute of Molecular Biology and Biotechnology, Greece.
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29
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Yau JOY, Chaichim C, Power JM, McNally GP. The Roles of Basolateral Amygdala Parvalbumin Neurons in Fear Learning. J Neurosci 2021; 41:9223-9234. [PMID: 34561234 PMCID: PMC8570827 DOI: 10.1523/jneurosci.2461-20.2021] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 09/14/2021] [Accepted: 09/17/2021] [Indexed: 11/21/2022] Open
Abstract
The basolateral amygdala (BLA) is obligatory for fear learning. This learning is linked to BLA excitatory projection neurons whose activity is regulated by complex networks of inhibitory interneurons, dominated by parvalbumin (PV)-expressing GABAergic neurons. The roles of these GABAergic interneurons in learning to fear and learning not to fear, activity profiles of these interneurons across the course of fear learning, and whether or how these change across the course of learning all remain poorly understood. Here, we used PV cell-type-specific recording and manipulation approaches in male transgenic PV-Cre rats during pavlovian fear conditioning to address these issues. We show that activity of BLA PV neurons during the moments of aversive reinforcement controls fear learning about aversive events, but activity during moments of nonreinforcement does not control fear extinction learning. Furthermore, we show expectation-modulation of BLA PV neurons during fear learning, with greater activity to an unexpected than expected aversive unconditioned stimulus (US). This expectation-modulation was specifically because of BLA PV neuron sensitivity to aversive prediction error. Finally, we show that BLA PV neuron function in fear learning is conserved across these variations in prediction error. We suggest that aversive prediction-error modulation of PV neurons could enable BLA fear-learning circuits to retain selectivity for specific sensory features of aversive USs despite variations in the strength of US inputs, thereby permitting the rapid updating of fear associations when these sensory features change.SIGNIFICANCE STATEMENT The capacity to learn about sources of danger in the environment is essential for survival. This learning depends on complex microcircuitries of inhibitory interneurons in the basolateral amygdala. Here, we show that parvalbumin-positive GABAergic interneurons in the rat basolateral amygdala are important for fear learning during moments of danger, but not for extinction learning during moments of safety, and that the activity of these neurons is modulated by expectation of danger. This may enable fear-learning circuits to retain selectivity for specific aversive events across variations in expectation, permitting the rapid updating of learning when aversive events change.
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Affiliation(s)
- Joanna Oi-Yue Yau
- School of Psychology, University of New South Wales Sydney, Sydney, New South Wales 2052, Australia
| | - Chanchanok Chaichim
- Department of Physiology, Translational Neuroscience Facility, School of Medical Sciences, University of New South Wales Sydney, Sydney, New South Wales 2052, Australia
| | - John M Power
- Department of Physiology, Translational Neuroscience Facility, School of Medical Sciences, University of New South Wales Sydney, Sydney, New South Wales 2052, Australia
| | - Gavan P McNally
- School of Psychology, University of New South Wales Sydney, Sydney, New South Wales 2052, Australia
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30
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Glas A, Hübener M, Bonhoeffer T, Goltstein PM. Spaced training enhances memory and prefrontal ensemble stability in mice. Curr Biol 2021; 31:4052-4061.e6. [PMID: 34324833 DOI: 10.1016/j.cub.2021.06.085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 06/01/2021] [Accepted: 06/28/2021] [Indexed: 11/15/2022]
Abstract
It is commonly acknowledged that memory is substantially improved when learning is distributed over time, an effect called the "spacing effect". So far it has not been studied how spaced learning affects the neuronal ensembles presumably underlying memory. In the present study, we investigate whether trial spacing increases the stability or size of neuronal ensembles. Mice were trained in the "everyday memory" task, an appetitive, naturalistic, delayed matching-to-place task. Spacing trials by 60 min produced more robust memories than training with shorter or longer intervals. c-Fos labeling and chemogenetic inactivation established the involvement of the dorsomedial prefrontal cortex (dmPFC) in successful memory storage. In vivo calcium imaging of excitatory dmPFC neurons revealed that longer trial spacing increased the similarity of the population activity pattern on subsequent encoding trials and upon retrieval. Conversely, trial spacing did not affect the size of the total neuronal ensemble or the size of subpopulations dedicated to specific task-related behaviors and events. Thus, spaced learning promotes reactivation of prefrontal neuronal ensembles processing episodic-like memories.
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Affiliation(s)
- Annet Glas
- Max Planck Institute of Neurobiology, Am Klopferspitz 18, 82152 Martinsried, Germany; Graduate School of Systemic Neurosciences, Ludwig-Maximilians-Universität München, Großhaderner Straße 2, 82152 Martinsried, Germany
| | - Mark Hübener
- Max Planck Institute of Neurobiology, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Tobias Bonhoeffer
- Max Planck Institute of Neurobiology, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Pieter M Goltstein
- Max Planck Institute of Neurobiology, Am Klopferspitz 18, 82152 Martinsried, Germany.
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31
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Zhang J, Zhang Y, Pan Y, Xu Y, Xue Y. The neural foundation of associative memory: a dynamic functional connectivity study for right-handed young adults. Exp Brain Res 2021; 239:3527-3536. [PMID: 34537860 DOI: 10.1007/s00221-021-06222-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Accepted: 09/12/2021] [Indexed: 11/30/2022]
Abstract
The medial temporal lobe (MTL) is the core neural construction related to associative memory. This study sought to explore the dynamic functional connectivity (dFC) between the subdivisions of MTL and other regions in the whole brain. Additionally, it sought to determine relationships between connectivity stability and associative memory function, to elucidate the neural foundation of associative memory from the perspectives of dFC. A Wechsler Memory Scale China revised edition (WMS-RC) measurement and a resting-state functional magnetic resonance imaging were conducted to clarify adults' function of associative memory and dFC patterns in subdivisions of the MTL. A multiple regression analysis was carried out to analyze the relationships described above. The results demonstrated that (i) connectivity in the left brain included the anterior hippocampus (aHIP) and right fusiform (Fusiform_R), middle hippocampus (mHIP) and right inferior parietal lobule (IPL_R), posterior hippocampus (pHIP) and left inferior parietal lobule (IPL_L), perirhinal cortex (PRC) and left supramarginal gyrus (SMG_L), entorhinal cortex (ERC) and [left middle temporal gyrus (MTG_L), left superior parietal lobule (SPL_L), right fusiform (Fusiform_R)], anterior parahippocampal cortex (aPHC) and right precentral gyrus (PCG_R); (ii) connectivity in the right brain included the aHIP and right supramarginal gyrus (SMG_R), mHIP and left paracentral lobule (PCL_L), pHIP and left superior occipital gyrus (SOG_L), PRC and left middle occipital gyrus (MOG_L), ERC and right middle occipital gyrus (MOG_R); (iii) for most connectivity patterns, the more stable the dFC, the better are the associative memory functions. This study elucidates the neural foundations of associative memory in terms of dFC patterns.
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Affiliation(s)
- Jian Zhang
- School of Psychology, Guizhou Normal University, Guiyang, People's Republic of China
| | - Yujia Zhang
- Department of Community Prevention, Tianjin Anding Hospital, Tianjin, People's Republic of China
| | - Yun Pan
- School of Psychology, Guizhou Normal University, Guiyang, People's Republic of China
| | - Yong Xu
- Department of Psychiatry, First Hospital/First Clinical Medical College of Shanxi Medical University, 85 Jiefang South Road, Taiyuan, 030001, People's Republic of China. .,MDT Center for Cognitive Impairment and Sleep Disorders, First Hospital of Shanxi Medical University, Taiyuan, People's Republic of China.
| | - Yunzhen Xue
- Department of Humanities and Social Science, Shanxi Medical University, 56 Xinjian South Road, Taiyuan, 030001, People's Republic of China.
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32
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Cummings KA, Lacagnina AF, Clem RL. GABAergic microcircuitry of fear memory encoding. Neurobiol Learn Mem 2021; 184:107504. [PMID: 34425220 DOI: 10.1016/j.nlm.2021.107504] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 08/12/2021] [Accepted: 08/15/2021] [Indexed: 12/30/2022]
Abstract
The paradigm of fear conditioning is largely responsible for our current understanding of how memories are encoded at the cellular level. Its most fundamental underlying mechanism is considered to be plasticity of synaptic connections between excitatory projection neurons (PNs). However, recent studies suggest that while PNs execute critical memory functions, their activity at key stages of learning and recall is extensively orchestrated by a diverse array of GABAergic interneurons (INs). Here we review the contributions of genetically-defined INs to processing of threat-related stimuli in fear conditioning, with a particular focus on how synaptic interactions within interconnected networks of INs modulates PN activity through both inhibition and disinhibition. Furthermore, we discuss accumulating evidence that GABAergic microcircuits are an important locus for synaptic plasticity during fear learning and therefore a viable substrate for long-term memory. These findings suggest that further investigation of INs could unlock unique conceptual insights into the organization and function of fear memory networks.
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Affiliation(s)
- Kirstie A Cummings
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States; Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States; Department of Neurobiology, University of Alabama Birmingham School of Medicine, Birmingham, AL 35294, United States
| | - Anthony F Lacagnina
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States; Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States
| | - Roger L Clem
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States; Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States.
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33
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Giorgi C, Marinelli S. Roles and Transcriptional Responses of Inhibitory Neurons in Learning and Memory. Front Mol Neurosci 2021; 14:689952. [PMID: 34211369 PMCID: PMC8239217 DOI: 10.3389/fnmol.2021.689952] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 05/18/2021] [Indexed: 12/26/2022] Open
Abstract
Increasing evidence supports a model whereby memories are encoded by sparse ensembles of neurons called engrams, activated during memory encoding and reactivated upon recall. An engram consists of a network of cells that undergo long-lasting modifications of their transcriptional programs and connectivity. Ground-breaking advancements in this field have been made possible by the creative exploitation of the characteristic transcriptional responses of neurons to activity, allowing both engram labeling and manipulation. Nevertheless, numerous aspects of engram cell-type composition and function remain to be addressed. As recent transcriptomic studies have revealed, memory encoding induces persistent transcriptional and functional changes in a plethora of neuronal subtypes and non-neuronal cells, including glutamatergic excitatory neurons, GABAergic inhibitory neurons, and glia cells. Dissecting the contribution of these different cellular classes to memory engram formation and activity is quite a challenging yet essential endeavor. In this review, we focus on the role played by the GABAergic inhibitory component of the engram through two complementary lenses. On one hand, we report on available physiological evidence addressing the involvement of inhibitory neurons to different stages of memory formation, consolidation, storage and recall. On the other, we capitalize on a growing number of transcriptomic studies that profile the transcriptional response of inhibitory neurons to activity, revealing important clues on their potential involvement in learning and memory processes. The picture that emerges suggests that inhibitory neurons are an essential component of the engram, likely involved in engram allocation, in tuning engram excitation and in storing the memory trace.
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Affiliation(s)
- Corinna Giorgi
- CNR, Institute of Molecular Biology and Pathology, Rome, Italy.,European Brain Research Institute (EBRI), Fondazione Rita Levi-Montalcini, Rome, Italy
| | - Silvia Marinelli
- European Brain Research Institute (EBRI), Fondazione Rita Levi-Montalcini, Rome, Italy
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34
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Hájos N. Interneuron Types and Their Circuits in the Basolateral Amygdala. Front Neural Circuits 2021; 15:687257. [PMID: 34177472 PMCID: PMC8222668 DOI: 10.3389/fncir.2021.687257] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 05/11/2021] [Indexed: 11/29/2022] Open
Abstract
The basolateral amygdala (BLA) is a cortical structure based on its cell types, connectivity features, and developmental characteristics. This part of the amygdala is considered to be the main entry site of processed and multisensory information delivered via cortical and thalamic afferents. Although GABAergic inhibitory cells in the BLA comprise only 20% of the entire neuronal population, they provide essential control over proper network operation. Previous studies have uncovered that GABAergic cells in the basolateral amygdala are as diverse as those present in other cortical regions, including the hippocampus and neocortex. To understand the role of inhibitory cells in various amygdala functions, we need to reveal the connectivity and input-output features of the different types of GABAergic cells. Here, I review the recent achievements in uncovering the diversity of GABAergic cells in the basolateral amygdala with a specific focus on the microcircuit organization of these inhibitory cells.
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Affiliation(s)
- Norbert Hájos
- Laboratory of Network Neurophysiology, ELRN Institute of Experimental Medicine, Budapest, Hungary
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35
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Wu CH, Ramos R, Katz DB, Turrigiano GG. Homeostatic synaptic scaling establishes the specificity of an associative memory. Curr Biol 2021; 31:2274-2285.e5. [PMID: 33798429 PMCID: PMC8187282 DOI: 10.1016/j.cub.2021.03.024] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 03/01/2021] [Accepted: 03/08/2021] [Indexed: 12/21/2022]
Abstract
Correlation-based (Hebbian) forms of synaptic plasticity are crucial for the initial encoding of associative memories but likely insufficient to enable the stable storage of multiple specific memories within neural circuits. Theoretical studies have suggested that homeostatic synaptic normalization rules provide an essential countervailing force that can stabilize and expand memory storage capacity. Although such homeostatic mechanisms have been identified and studied for decades, experimental evidence that they play an important role in associative memory is lacking. Here, we show that synaptic scaling, a widely studied form of homeostatic synaptic plasticity that globally renormalizes synaptic strengths, is dispensable for initial associative memory formation but crucial for the establishment of memory specificity. We used conditioned taste aversion (CTA) learning, a form of associative learning that relies on Hebbian mechanisms within gustatory cortex (GC), to show that animals conditioned to avoid saccharin initially generalized this aversion to other novel tastants. Specificity of the aversion to saccharin emerged slowly over a time course of many hours and was associated with synaptic scaling down of excitatory synapses onto conditioning-active neuronal ensembles within gustatory cortex. Blocking synaptic scaling down in the gustatory cortex enhanced the persistence of synaptic strength increases induced by conditioning and prolonged the duration of memory generalization. Taken together, these findings demonstrate that synaptic scaling is crucial for sculpting the specificity of an associative memory and suggest that the relative strengths of Hebbian and homeostatic plasticity can modulate the balance between stable memory formation and memory generalization.
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Affiliation(s)
- Chi-Hong Wu
- Department of Biology, Brandeis University, Waltham, MA 02453, USA
| | - Raul Ramos
- Department of Biology, Brandeis University, Waltham, MA 02453, USA
| | - Donald B Katz
- Department of Psychology, Brandeis University, Waltham, MA 02453, USA
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36
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Han DH, Park P, Choi DI, Bliss TVP, Kaang BK. The essence of the engram: Cellular or synaptic? Semin Cell Dev Biol 2021; 125:122-135. [PMID: 34103208 DOI: 10.1016/j.semcdb.2021.05.033] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 05/28/2021] [Accepted: 05/31/2021] [Indexed: 10/21/2022]
Abstract
Memory is composed of various phases including cellular consolidation, systems consolidation, reconsolidation, and extinction. In the last few years it has been shown that simple association memories can be encoded by a subset of the neuronal population called engram cells. Activity of these cells is necessary and sufficient for the recall of association memory. However, it is unclear which molecular mechanisms allow cellular engrams to encode the diverse phases of memory. Further research is needed to examine the possibility that it is the synapses between engram cells (the synaptic engram) that constitute the memory. In this review we summarize recent findings on cellular engrams with a focus on different phases of memory, and discuss the distinct molecular mechanism required for cellular and synaptic engrams.
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Affiliation(s)
- Dae Hee Han
- School of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Pojeong Park
- School of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Dong Il Choi
- School of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Tim V P Bliss
- Group leader emeritus, The Francis Crick Institute, 1 Midland Rd, Somers Town, London NW1 1AT, UK
| | - Bong-Kiun Kaang
- School of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul 08826, Republic of Korea.
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Wingert JC, Sorg BA. Impact of Perineuronal Nets on Electrophysiology of Parvalbumin Interneurons, Principal Neurons, and Brain Oscillations: A Review. Front Synaptic Neurosci 2021; 13:673210. [PMID: 34040511 PMCID: PMC8141737 DOI: 10.3389/fnsyn.2021.673210] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 04/14/2021] [Indexed: 12/11/2022] Open
Abstract
Perineuronal nets (PNNs) are specialized extracellular matrix structures that surround specific neurons in the brain and spinal cord, appear during critical periods of development, and restrict plasticity during adulthood. Removal of PNNs can reinstate juvenile-like plasticity or, in cases of PNN removal during early developmental stages, PNN removal extends the critical plasticity period. PNNs surround mainly parvalbumin (PV)-containing, fast-spiking GABAergic interneurons in several brain regions. These inhibitory interneurons profoundly inhibit the network of surrounding neurons via their elaborate contacts with local pyramidal neurons, and they are key contributors to gamma oscillations generated across several brain regions. Among other functions, these gamma oscillations regulate plasticity associated with learning, decision making, attention, cognitive flexibility, and working memory. The detailed mechanisms by which PNN removal increases plasticity are only beginning to be understood. Here, we review the impact of PNN removal on several electrophysiological features of their underlying PV interneurons and nearby pyramidal neurons, including changes in intrinsic and synaptic membrane properties, brain oscillations, and how these changes may alter the integration of memory-related information. Additionally, we review how PNN removal affects plasticity-associated phenomena such as long-term potentiation (LTP), long-term depression (LTD), and paired-pulse ratio (PPR). The results are discussed in the context of the role of PV interneurons in circuit function and how PNN removal alters this function.
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Affiliation(s)
- Jereme C Wingert
- Program in Neuroscience, Robert S. Dow Neurobiology Laboratories, Legacy Research Institute, Portland, OR, United States
| | - Barbara A Sorg
- Program in Neuroscience, Robert S. Dow Neurobiology Laboratories, Legacy Research Institute, Portland, OR, United States
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38
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Neuronal ensembles in memory processes. Semin Cell Dev Biol 2021; 125:136-143. [PMID: 33858772 DOI: 10.1016/j.semcdb.2021.04.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 03/30/2021] [Accepted: 04/01/2021] [Indexed: 12/19/2022]
Abstract
A neuronal ensemble represents the concomitant activity of a specific group of neurons that could encompass a broad repertoire of brain functions such as motor, perceptual, memory or cognitive states. On the other hand, a memory engram portrays the physical manifestation of memory or the changes that enable learning and retrieval. Engram studies focused for many years on finding where memories are stored as in, which cells or brain regions represent a memory trace, and disregarded the investigation of how neuronal activity patterns give rise to such memories. Recent experiments suggest that the association and reactivation of specific neuronal groups could be the main mechanism underlying the brain's ability to remember past experiences and envision future actions. Thus, the growing consensus is that the interaction between neuronal ensembles could allow sequential activity patterns to become memories and recurrent memories to compose complex behaviors. The goal of this review is to propose how the neuronal ensemble framework could be translated and useful to understand memory processes.
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Nucleus accumbens fast-spiking interneurons in motivational and addictive behaviors. Mol Psychiatry 2021; 26:234-246. [PMID: 32071384 PMCID: PMC7431371 DOI: 10.1038/s41380-020-0683-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 01/02/2020] [Accepted: 02/07/2020] [Indexed: 02/07/2023]
Abstract
The development of drug addiction is associated with functional adaptations within the reward circuitry, within which the nucleus accumbens (NAc) is anatomically positioned as an interface between motivational salience and behavioral output. The functional output of NAc is profoundly altered after exposure to drugs of abuse, and some of the functional changes continue to evolve during drug abstinence, contributing to numerous emotional and motivational alterations related drug taking, seeking, and relapse. As in most brain regions, the functional output of NAc is critically dependent on the dynamic interaction between excitation and inhibition. One of the most prominent sources of inhibition within the NAc arises from fast-spiking interneurons (FSIs). Each NAc FSI innervates hundreds of principal neurons, and orchestrates population activity through its powerful and sustained feedforward inhibition. While the role of NAc FSIs in the context of drug addiction remains poorly understood, emerging evidence suggests that FSIs and FSI-mediated local circuits are key targets for drugs of abuse to tilt the functional output of NAc toward a motivational state favoring drug seeking and relapse. In this review, we discuss recent findings and our conceptualization about NAc FSI-mediated regulation of motivated and cocaine-induced behaviors. We hope that the conceptual framework proposed in this review may provide a useful guidance for ongoing and future studies to determine how FSIs influence the function of NAc and related reward circuits, ultimately leading to addictive behaviors.
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Brebner LS, Ziminski JJ, Margetts-Smith G, Sieburg MC, Hall CN, Heintz TG, Lagnado L, Hirrlinger J, Crombag HS, Koya E. Extinction of cue-evoked food-seeking recruits a GABAergic interneuron ensemble in the dorsal medial prefrontal cortex of mice. Eur J Neurosci 2020; 52:3723-3737. [PMID: 32307758 DOI: 10.1111/ejn.14754] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 03/25/2020] [Accepted: 04/10/2020] [Indexed: 11/27/2022]
Abstract
Animals must quickly adapt food-seeking strategies to locate nutrient sources in dynamically changing environments. Learned associations between food and environmental cues that predict its availability promote food-seeking behaviors. However, when such cues cease to predict food availability, animals undergo "extinction" learning, resulting in the inhibition of food-seeking responses. Repeatedly activated sets of neurons, or "neuronal ensembles," in the dorsal medial prefrontal cortex (dmPFC) are recruited following appetitive conditioning and undergo physiological adaptations thought to encode cue-reward associations. However, little is known about how the recruitment and intrinsic excitability of such dmPFC ensembles are modulated by extinction learning. Here, we used in vivo 2-Photon imaging in male Fos-GFP mice that express green fluorescent protein (GFP) in recently behaviorally activated neurons to determine the recruitment of activated pyramidal and GABAergic interneuron dmPFC ensembles during extinction. During extinction, we revealed a persistent activation of a subset of interneurons which emerged from a wider population of interneurons activated during the initial extinction session. This activation pattern was not observed in pyramidal cells, and extinction learning did not modulate the excitability properties of activated pyramidal cells. Moreover, extinction learning reduced the likelihood of reactivation of pyramidal cells activated during the initial extinction session. Our findings illuminate novel neuronal activation patterns in the dmPFC underlying extinction of food-seeking, and in particular, highlight an important role for interneuron ensembles in this inhibitory form of learning.
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Affiliation(s)
- Leonie S Brebner
- Sussex Neuroscience, School of Psychology, University of Sussex, Falmer, UK
| | - Joseph J Ziminski
- Sussex Neuroscience, School of Psychology, University of Sussex, Falmer, UK
| | | | - Meike C Sieburg
- Sussex Neuroscience, School of Psychology, University of Sussex, Falmer, UK
| | - Catherine N Hall
- Sussex Neuroscience, School of Psychology, University of Sussex, Falmer, UK
| | - Tristan G Heintz
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Falmer, UK
| | - Leon Lagnado
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Falmer, UK
| | - Johannes Hirrlinger
- Carl-Ludwig-Institute for Physiology, University of Leipzig, Leipzig, Germany.,Department of Neurogenetics, Max-Planck-Institute for Experimental Medicine, Göttingen, Germany
| | - Hans S Crombag
- Sussex Neuroscience, School of Psychology, University of Sussex, Falmer, UK
| | - Eisuke Koya
- Sussex Neuroscience, School of Psychology, University of Sussex, Falmer, UK
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Josselyn SA, Tonegawa S. Memory engrams: Recalling the past and imagining the future. Science 2020; 367:367/6473/eaaw4325. [PMID: 31896692 DOI: 10.1126/science.aaw4325] [Citation(s) in RCA: 446] [Impact Index Per Article: 111.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
In 1904, Richard Semon introduced the term "engram" to describe the neural substrate for storing memories. An experience, Semon proposed, activates a subset of cells that undergo off-line, persistent chemical and/or physical changes to become an engram. Subsequent reactivation of this engram induces memory retrieval. Although Semon's contributions were largely ignored in his lifetime, new technologies that allow researchers to image and manipulate the brain at the level of individual neurons has reinvigorated engram research. We review recent progress in studying engrams, including an evaluation of evidence for the existence of engrams, the importance of intrinsic excitability and synaptic plasticity in engrams, and the lifetime of an engram. Together, these findings are beginning to define an engram as the basic unit of memory.
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Affiliation(s)
- Sheena A Josselyn
- Program in Neurosciences & Mental Health, Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada. .,Department of Psychology, University of Toronto, Toronto, Ontario M5S 3G3, Canada.,Department of Physiology, University of Toronto, Toronto, Ontario M5G 1X8, Canada.,Institute of Medical Sciences, University of Toronto, Toronto, Ontario M5S 1A8, Canada.,Brain, Mind & Consciousness Program, Canadian Institute for Advanced Research (CIFAR), Toronto, Ontario M5G 1M1, Canada
| | - Susumu Tonegawa
- RIKEN-MIT Laboratory for Neural Circuit Genetics at the Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA. .,Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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Bessières B, Travaglia A, Mowery TM, Zhang X, Alberini CM. Early life experiences selectively mature learning and memory abilities. Nat Commun 2020; 11:628. [PMID: 32005863 PMCID: PMC6994621 DOI: 10.1038/s41467-020-14461-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 01/09/2020] [Indexed: 01/24/2023] Open
Abstract
The mechanisms underlying the maturation of learning and memory abilities are poorly understood. Here we show that episodic learning produces unique biological changes in the hippocampus of infant rats and mice compared to juveniles and adults. These changes include persistent neuronal activation, BDNF-dependent increase in the excitatory synapse markers synaptophysin and PSD-95, and significant maturation of AMPA receptor synaptic responses. Inhibition of PSD-95 induction following learning impairs both AMPA receptor response maturation and infantile memory, indicating that the synapse formation/maturation is necessary for creating infantile memories. Conversely, capturing the learning-induced changes by presenting a subsequent learning experience or by chemogenetic activation of the neural ensembles tagged by learning matures memory functional competence. This memory competence is selective for the type of experience encountered, as it transfers within similar hippocampus-dependent learning domains but not to other hippocampus-dependent types of learning. Thus, experiences in early life produce selective maturation of memory abilities.
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Affiliation(s)
- Benjamin Bessières
- Center for Neural Science, New York University, New York, NY, 10003, USA
| | - Alessio Travaglia
- Center for Neural Science, New York University, New York, NY, 10003, USA
| | - Todd M Mowery
- Center for Neural Science, New York University, New York, NY, 10003, USA
| | - Xinying Zhang
- Center for Neural Science, New York University, New York, NY, 10003, USA
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43
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Maddox SA, Hartmann J, Ross RA, Ressler KJ. Deconstructing the Gestalt: Mechanisms of Fear, Threat, and Trauma Memory Encoding. Neuron 2019; 102:60-74. [PMID: 30946827 DOI: 10.1016/j.neuron.2019.03.017] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Revised: 03/03/2019] [Accepted: 03/12/2019] [Indexed: 01/14/2023]
Abstract
Threat processing is central to understanding debilitating fear- and trauma-related disorders such as posttraumatic stress disorder (PTSD). Progress has been made in understanding the neural circuits underlying the "engram" of threat or fear memory formation that complements a decades-old appreciation of the neurobiology of fear and threat involving hub structures such as the amygdala. In this review, we examine key recent findings, as well as integrate the importance of hormonal and physiological approaches, to provide a broader perspective of how bodily systems engaged in threat responses may interact with amygdala-based circuits in the encoding and updating of threat-related memory. Understanding how trauma-related memories are encoded and updated throughout the brain and the body will ultimately lead to novel biologically-driven approaches for treatment and prevention.
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Affiliation(s)
- Stephanie A Maddox
- Neurobiology of Fear Laboratory, Division of Depression and Anxiety Disorders, McLean Hospital, 115 Mill Street, Belmont, MA 02478, USA; Department of Psychiatry, Harvard Medical School, Boston, MA 02115, USA
| | - Jakob Hartmann
- Neurobiology of Fear Laboratory, Division of Depression and Anxiety Disorders, McLean Hospital, 115 Mill Street, Belmont, MA 02478, USA; Department of Psychiatry, Harvard Medical School, Boston, MA 02115, USA
| | - Rachel A Ross
- Neurobiology of Fear Laboratory, Division of Depression and Anxiety Disorders, McLean Hospital, 115 Mill Street, Belmont, MA 02478, USA; Department of Psychiatry, Harvard Medical School, Boston, MA 02115, USA
| | - Kerry J Ressler
- Neurobiology of Fear Laboratory, Division of Depression and Anxiety Disorders, McLean Hospital, 115 Mill Street, Belmont, MA 02478, USA; Department of Psychiatry, Harvard Medical School, Boston, MA 02115, USA.
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44
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Adaptive disinhibitory gating by VIP interneurons permits associative learning. Nat Neurosci 2019; 22:1834-1843. [DOI: 10.1038/s41593-019-0508-y] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 09/05/2019] [Indexed: 01/19/2023]
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45
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Reinhard SM, Rais M, Afroz S, Hanania Y, Pendi K, Espinoza K, Rosenthal R, Binder DK, Ethell IM, Razak KA. Reduced perineuronal net expression in Fmr1 KO mice auditory cortex and amygdala is linked to impaired fear-associated memory. Neurobiol Learn Mem 2019; 164:107042. [PMID: 31326533 PMCID: PMC7519848 DOI: 10.1016/j.nlm.2019.107042] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 06/20/2019] [Accepted: 07/10/2019] [Indexed: 02/06/2023]
Abstract
Fragile X Syndrome (FXS) is a leading cause of heritable intellectual disability and autism. Humans with FXS show anxiety, sensory hypersensitivity and impaired learning. The mechanisms of learning impairments can be studied in the mouse model of FXS, the Fmr1 KO mouse, using tone-associated fear memory paradigms. Our previous study reported impaired development of parvalbumin (PV) positive interneurons and perineuronal nets (PNN) in the auditory cortex of Fmr1 KO mice. A recent study suggested PNN dynamics in the auditory cortex following tone-shock association is necessary for fear expression. Together these data suggest that abnormal PNN regulation may underlie tone-fear association learning deficits in Fmr1 KO mice. We tested this hypothesis by quantifying PV and PNN expression in the amygdala, hippocampus and auditory cortex of Fmr1 KO mice following fear conditioning. We found impaired tone-associated memory formation in Fmr1 KO mice. This was paralleled by impaired learning-associated regulation of PNNs in the superficial layers of auditory cortex in Fmr1 KO mice. PV cell density decreased in the auditory cortex in response to fear conditioning in both WT and Fmr1 KO mice. Learning-induced increase of PV expression in the CA3 hippocampus was only observed in WT mice. We also found reduced PNN density in the amygdala and auditory cortex of Fmr1 KO mice in all conditions, as well as reduced PNN intensity in CA2 hippocampus. There was a positive correlation between tone-associated memory and PNN density in the amygdala and auditory cortex, consistent with a tone-association deficit. Altogether our studies suggest a link between impaired PV and PNN regulation within specific regions of the fear conditioning circuit and impaired tone memory formation in Fmr1 KO mice.
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Affiliation(s)
- Sarah M Reinhard
- Psychology Department and Psychology Graduate Program, University of California, Riverside, CA 92521, USA
| | - Maham Rais
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA 92521, USA
| | - Sonia Afroz
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA 92521, USA
| | - Yasmien Hanania
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA 92521, USA
| | - Kasim Pendi
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA 92521, USA
| | - Katherine Espinoza
- Psychology Department and Psychology Graduate Program, University of California, Riverside, CA 92521, USA; Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA 92521, USA
| | - Robert Rosenthal
- Psychology Department and Psychology Graduate Program, University of California, Riverside, CA 92521, USA
| | - Devin K Binder
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA 92521, USA; Neuroscience Graduate Program, University of California, Riverside, CA 92521, USA
| | - Iryna M Ethell
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA 92521, USA; Neuroscience Graduate Program, University of California, Riverside, CA 92521, USA.
| | - Khaleel A Razak
- Psychology Department and Psychology Graduate Program, University of California, Riverside, CA 92521, USA; Neuroscience Graduate Program, University of California, Riverside, CA 92521, USA.
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Negative Memory Engrams in the Hippocampus Enhance the Susceptibility to Chronic Social Defeat Stress. J Neurosci 2019; 39:7576-7590. [PMID: 31405928 DOI: 10.1523/jneurosci.1958-18.2019] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 07/15/2019] [Accepted: 07/19/2019] [Indexed: 11/21/2022] Open
Abstract
The hippocampus has been highly implicated in depression symptoms. Recent findings suggest that the expression and susceptibility of depression symptoms are related to the enhanced functioning of the hippocampus. We reasoned that hippocampal engrams, which represent ensembles of neurons with increased activity after memory formation, could underlie some contributions of the hippocampus to depression symptoms. Using the chronic social defeat stress model, we examined social defeat-related hippocampal engrams in mice that are either susceptible or resilient to the stressor. TetTag mice were used to label social defeat-related hippocampal ensembles by LacZ. Engram cells correspond to ensembles that were reactivated by the same stressor. Compared with resilient and nonstressed control mice, susceptible mice exhibited a higher reactivation of social defeat-related LacZ-labeled cells (i.e., engram cells) in both the dorsal and ventral hippocampal CA1 regions. The density of CA1 engram cells correlated with the level of social avoidance. Using DREADD and optogenetic approaches to activate and inactivate social defeat-related CA1 engram cells enhanced and suppressed social avoidance, respectively. Increased engram cells in susceptible mice could not be found in the dentate gyrus. Susceptible mice exhibited more negative stimuli-related, but not neutral stimuli-related, CA1 engram cells than resilient mice in the dorsal hippocampus. Finally, chronic, but not a short and subthreshold, social defeat protocol was necessary to increase CA1 engram cell density. The susceptibility to chronic social defeat stress is regulated by hippocampal CA1 engrams for negative memory. Hippocampal negative memory engrams may underlie the vulnerability and expression of cognitive symptoms in depression.SIGNIFICANCE STATEMENT We provided evidence that negative memory hippocampal engrams contribute to the susceptibility to developing depression-related behavior after chronic social defeat stress. The activation of positive memory engrams has been shown to alleviate depression-related behaviors, while our findings reveal the pathological roles of negative memory engrams that could lead to those behaviors. Increased negative memory engrams could be a downstream effect of the reported high hippocampal activity in animal models and patients with depression. Unlike affective symptoms, we know much less about the cellular mechanisms of the cognitive symptoms of depression. Given the crucial roles of hippocampal engrams in memory formation, enhanced reactivation of negative memory engrams could be an important cellular mechanism that underlies the cognitive symptoms of depression.
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The role of the genome in experience-dependent plasticity: Extending the analogy of the genomic action potential. Proc Natl Acad Sci U S A 2019; 117:23252-23260. [PMID: 31127037 DOI: 10.1073/pnas.1820837116] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Our past experiences shape our current and future behavior. These experiences must leave some enduring imprint on our brains, altering neural circuits that mediate behavior and contributing to our individual differences. As a framework for understanding how experiences might produce lasting changes in neural circuits, Clayton [D. F. Clayton, Neurobiol. Learn. Mem. 74, 185-216 (2000)] introduced the concept of the genomic action potential (gAP)-a structured genomic response in the brain to acute experience. Similar to the familiar electrophysiological action potential (eAP), the gAP also provides a means for integrating afferent patterns of activity but on a slower timescale and with longer-lasting effects. We revisit this concept in light of contemporary work on experience-dependent modification of neural circuits. We review the "Immediate Early Gene" (IEG) response, the starting point for understanding the gAP. We discuss evidence for its involvement in the encoding of experience to long-term memory across time and biological levels of organization ranging from individual cells to cell ensembles and whole organisms. We explore distinctions between memory encoding and homeostatic functions and consider the potential for perpetuation of the imprint of experience through epigenetic mechanisms. We describe a specific example of a gAP in humans linked to individual differences in the response to stress. Finally, we identify key objectives and new tools for continuing research in this area.
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48
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Ramsaran AI, Schlichting ML, Frankland PW. The ontogeny of memory persistence and specificity. Dev Cogn Neurosci 2019; 36:100591. [PMID: 30316637 PMCID: PMC6969236 DOI: 10.1016/j.dcn.2018.09.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 09/06/2018] [Accepted: 09/25/2018] [Indexed: 02/01/2023] Open
Abstract
Interest in the ontogeny of memory blossomed in the twentieth century following the initial observations that memories from infancy and early childhood are rapidly forgotten. The intense exploration of infantile amnesia in subsequent years has led to a thorough characterization of its psychological determinants, although the neurobiology of memory persistence has long remained elusive. By contrast, other phenomena in the ontogeny of memory like infantile generalization have received relatively less attention. Despite strong evidence for reduced memory specificity during ontogeny, infantile generalization is poorly understood from psychological and neurobiological perspectives. In this review, we examine the ontogeny of memory persistence and specificity in humans and nonhuman animals at the levels of behavior and the brain. To this end, we first describe the behavioral phenotypes associated with each phenomenon. Looking into the brain, we then discuss neurobiological mechanisms in the hippocampus that contribute to the ontogeny of memory. Hippocampal neurogenesis and critical period mechanisms have recently been discovered to underlie amnesia during early development, and at the same time, we speculate that similar processes may contribute to the early bias towards memory generalization.
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Affiliation(s)
- Adam I Ramsaran
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, M5G 1X8, Canada; Department of Psychology, University of Toronto, Toronto, M5S 3G3, Canada
| | | | - Paul W Frankland
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, M5G 1X8, Canada; Department of Psychology, University of Toronto, Toronto, M5S 3G3, Canada; Department of Physiology, University of Toronto, Toronto, M5S 1A8, Canada; Institute of Medical Science, University of Toronto, Toronto, M5S 1A8, Canada; Child & Brain Development Program, Canadian Institute for Advanced Research (CIFAR), Toronto, M5G 1M1, Canada.
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A model of amygdala function following plastic changes at specific synapses during extinction. Neurobiol Stress 2019; 10:100159. [PMID: 31193487 PMCID: PMC6535631 DOI: 10.1016/j.ynstr.2019.100159] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2018] [Revised: 03/26/2019] [Accepted: 03/27/2019] [Indexed: 11/21/2022] Open
Abstract
The synaptic networks in the amygdala have been the subject of intense interest in recent times, primarily because of the role of this structure in emotion. Fear and its extinction depend on the workings of these networks, with particular interest in extinction because of its potential to ameliorate adverse symptoms associated with post-traumatic stress disorder. Here we place emphasis on the extinction networks revealed by recent techniques, and on the probable plasticity properties of their synaptic connections. We use modules of neurons representing each of the principal components identified as involved in extinction. Each of these modules consists of neural networks, containing specific ratios of excitatory and specialized inhibitory neurons as well as synaptic plasticity mechanisms appropriate for the component of the amygdala they represent. While these models can produce dynamic output, here we concentrate on the equilibrium outputs and do not model the details of the plasticity mechanisms. Pavlovian fear conditioning generates a fear memory in the lateral amygdala module that leads to activation of neurons in the basal nucleus fear module but not in the basal nucleus extinction module. Extinction protocols excite infralimbic medial prefrontal cortex neurons (IL) which in turn excite so-called extinction neurons in the amygdala, leading to the release of endocannabinoids from them and an increase in efficacy of synapses formed by lateral amygdala neurons on them. The model simulations show how such a mechanism could explain experimental observations involving the role of IL as well as endocannabinoids in different temporal phases of extinction.
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50
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Albo Z, Gräff J. The mysteries of remote memory. Philos Trans R Soc Lond B Biol Sci 2019; 373:rstb.2017.0029. [PMID: 29352028 PMCID: PMC5790827 DOI: 10.1098/rstb.2017.0029] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/30/2017] [Indexed: 12/16/2022] Open
Abstract
Long-lasting memories form the basis of our identity as individuals and lie central in shaping future behaviours that guide survival. Surprisingly, however, our current knowledge of how such memories are stored in the brain and retrieved, as well as the dynamics of the circuits involved, remains scarce despite seminal technical and experimental breakthroughs in recent years. Traditionally, it has been proposed that, over time, information initially learnt in the hippocampus is stored in distributed cortical networks. This process-the standard theory of memory consolidation-would stabilize the newly encoded information into a lasting memory, become independent of the hippocampus, and remain essentially unmodifiable throughout the lifetime of the individual. In recent years, several pieces of evidence have started to challenge this view and indicate that long-lasting memories might already ab ovo be encoded, and subsequently stored in distributed cortical networks, akin to the multiple trace theory of memory consolidation. In this review, we summarize these recent findings and attempt to identify the biologically plausible mechanisms based on which a contextual memory becomes remote by integrating different levels of analysis: from neural circuits to cell ensembles across synaptic remodelling and epigenetic modifications. From these studies, remote memory formation and maintenance appear to occur through a multi-trace, dynamic and integrative cellular process ranging from the synapse to the nucleus, and represent an exciting field of research primed to change quickly as new experimental evidence emerges.This article is part of a discussion meeting issue 'Of mice and mental health: facilitating dialogue between basic and clinical neuroscientists'.
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Affiliation(s)
- Zimbul Albo
- Laboratory of Neuroepigenetics, Brain Mind Institute, School of Life Sciences, Ecole Polytechnique Féderale Lausanne, CH-1015 Lausanne, Switzerland
| | - Johannes Gräff
- Laboratory of Neuroepigenetics, Brain Mind Institute, School of Life Sciences, Ecole Polytechnique Féderale Lausanne, CH-1015 Lausanne, Switzerland
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