1
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Yan C, Mercaldo V, Jacob AD, Kramer E, Mocle A, Ramsaran AI, Tran L, Rashid AJ, Park S, Insel N, Redish AD, Frankland PW, Josselyn SA. Higher-order interactions between hippocampal CA1 neurons are disrupted in amnestic mice. Nat Neurosci 2024; 27:1794-1804. [PMID: 39030342 DOI: 10.1038/s41593-024-01713-4] [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: 05/07/2021] [Accepted: 06/18/2024] [Indexed: 07/21/2024]
Abstract
Across systems, higher-order interactions between components govern emergent dynamics. Here we tested whether contextual threat memory retrieval in mice relies on higher-order interactions between dorsal CA1 hippocampal neurons requiring learning-induced dendritic spine plasticity. We compared population-level Ca2+ transients as wild-type mice (with intact learning-induced spine plasticity and memory) and amnestic mice (TgCRND8 mice with high levels of amyloid-β and deficits in learning-induced spine plasticity and memory) were tested for memory. Using machine-learning classifiers with different capacities to use input data with complex interactions, our findings indicate complex neuronal interactions in the memory representation of wild-type, but not amnestic, mice. Moreover, a peptide that partially restored learning-induced spine plasticity also restored the statistical complexity of the memory representation and memory behavior in Tg mice. These findings provide a previously missing bridge between levels of analysis in memory research, linking receptors, spines, higher-order neuronal dynamics and behavior.
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Affiliation(s)
- Chen Yan
- Program in Neurosciences & Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
- Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada
- DeepMind, London, UK
| | - Valentina Mercaldo
- Program in Neurosciences & Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Alexander D Jacob
- Program in Neurosciences & Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
- Dept. of Psychology, University of Toronto, Toronto, Ontario, Canada
| | - Emily Kramer
- Program in Neurosciences & Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
- Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Andrew Mocle
- Program in Neurosciences & Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
- Dept. of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Adam I Ramsaran
- Program in Neurosciences & Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
- Dept. of Psychology, University of Toronto, Toronto, Ontario, Canada
| | - Lina Tran
- Program in Neurosciences & Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
- Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Asim J Rashid
- Program in Neurosciences & Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Sungmo Park
- Program in Neurosciences & Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Nathan Insel
- Program in Neurosciences & Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
- Dept. of Psychology, University of Montana, Missoula, MT, USA
- Department of Psychology, Wilfrid Laurier University, Waterloo, Ontario, Canada
| | - A David Redish
- Dept. of Neuroscience, University of Minnesota, Minneapolis, MN, USA
| | - Paul W Frankland
- Program in Neurosciences & Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada
- Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada
- Dept. of Psychology, University of Toronto, Toronto, Ontario, Canada
- Dept. of Physiology, University of Toronto, Toronto, Ontario, Canada
- Child & Brain Development Program, Canadian Institute for Advanced Research (CIFAR), Toronto, Ontario, Canada
| | - Sheena A Josselyn
- Program in Neurosciences & Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada.
- Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada.
- Dept. of Psychology, University of Toronto, Toronto, Ontario, Canada.
- Dept. of Physiology, University of Toronto, Toronto, Ontario, Canada.
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2
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Bessières B, Dupuis J, Groc L, Bontempi B, Nicole O. Synaptic rearrangement of NMDA receptors controls memory engram formation and malleability in the cortex. SCIENCE ADVANCES 2024; 10:eado1148. [PMID: 39213354 PMCID: PMC11364093 DOI: 10.1126/sciadv.ado1148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Accepted: 07/26/2024] [Indexed: 09/04/2024]
Abstract
Initially hippocampal dependent, memory representations rely on a broadly distributed cortical network as they mature over time. How these cortical engrams acquire stability during systems-level memory consolidation without compromising their dynamic nature remains unclear. We identified a highly responsive "consolidation switch" in the synaptic composition of N-methyl-d-aspartate receptors (NMDARs), which dictates the progressive embedding and persistence of enduring memories in the rat cortex. Cortical GluN2B subunit-containing NMDARs were preferentially recruited upon encoding of associative olfactory memory to support neuronal allocation of memory engrams. As consolidation proceeds, a learning-induced redistribution of GluN2B subunit-containing NMDARs outward synapses increased synaptic GluN2A subunit contribution and enabled stabilization of remote memories. In contrast, synaptic reincorporation of GluN2B subunits occurred during subsequent forgetting. By manipulating the surface distribution of GluN2A and GluN2B subunit-containing NMDARs at cortical synapses, we uncovered that the rearrangement of GluN2B-containing NMDARs constitutes an essential tuning mechanism that determines the fate of cortical memory engrams and controls their malleability.
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Affiliation(s)
- Benjamin Bessières
- Institut des Maladies Neurodégénératives, CNRS UMR 5293, Université de Bordeaux, Bordeaux 33000, France
| | - Julien Dupuis
- Institut Interdisciplinaire de Neurosciences, CNRS UMR 5297, Université de Bordeaux, Bordeaux 33000, France
| | - Laurent Groc
- Institut Interdisciplinaire de Neurosciences, CNRS UMR 5297, Université de Bordeaux, Bordeaux 33000, France
| | - Bruno Bontempi
- Institut des Maladies Neurodégénératives, CNRS UMR 5293, Université de Bordeaux, Bordeaux 33000, France
- Institut de Neurosciences Cognitives et Intégratives d’Aquitaine, CNRS UMR 5287, Université de Bordeaux, Bordeaux 33000, France
| | - Olivier Nicole
- Institut des Maladies Neurodégénératives, CNRS UMR 5293, Université de Bordeaux, Bordeaux 33000, France
- Institut Interdisciplinaire de Neurosciences, CNRS UMR 5297, Université de Bordeaux, Bordeaux 33000, France
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3
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Griffith EC, West AE, Greenberg ME. Neuronal enhancers fine-tune adaptive circuit plasticity. Neuron 2024:S0896-6273(24)00574-9. [PMID: 39208805 DOI: 10.1016/j.neuron.2024.08.002] [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: 05/01/2023] [Revised: 07/22/2024] [Accepted: 08/06/2024] [Indexed: 09/04/2024]
Abstract
Neuronal activity-regulated gene expression plays a crucial role in sculpting neural circuits that underpin adaptive brain function. Transcriptional enhancers are now recognized as key components of gene regulation that orchestrate spatiotemporally precise patterns of gene transcription. We propose that the dynamics of enhancer activation uniquely position these genomic elements to finely tune activity-dependent cellular plasticity. Enhancer specificity and modularity can be exploited to gain selective genetic access to specific cell states, and the precise modulation of target gene expression within restricted cellular contexts enabled by targeted enhancer manipulation allows for fine-grained evaluation of gene function. Mounting evidence also suggests that enduring stimulus-induced changes in enhancer states can modify target gene activation upon restimulation, thereby contributing to a form of cell-wide metaplasticity. We advocate for focused exploration of activity-dependent enhancer function to gain new insight into the mechanisms underlying brain plasticity and cognitive dysfunction.
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Affiliation(s)
- Eric C Griffith
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Anne E West
- Department of Neurobiology, Duke University Medical Center, Durham, NC, USA.
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4
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Niewinski NE, Hernandez D, Colicos MA. Detection of Memory Engrams in Mammalian Neuronal Circuits. eNeuro 2024; 11:ENEURO.0450-23.2024. [PMID: 38997146 PMCID: PMC11307552 DOI: 10.1523/eneuro.0450-23.2024] [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: 10/31/2023] [Revised: 06/06/2024] [Accepted: 07/04/2024] [Indexed: 07/14/2024] Open
Abstract
It has long been assumed that activity patterns persist in neuronal circuits after they are first experienced, as part of the process of information processing and storage by the brain. However, these "reverberations" of current activity have not been directly observed on a single-neuron level in a mammalian system. Here we demonstrate that specific induced activity patterns are retained in mature cultured hippocampal neuronal networks. Neurons within the network are induced to fire at a single frequency or in a more complex pattern containing two distinct frequencies. After the stimulation was stopped, the subsequent neuronal activity of hundreds of neurons in the network was monitored. In the case of single-frequency stimulation, it was observed that many of the neurons continue to fire at the same frequency that they were stimulated to fire at. Using a recurrent neural network trained to detect specific, more complex patterns, we found that the multiple-frequency stimulation patterns were also retained within the neuronal network. Moreover, it appears that the component frequencies of the more complex patterns are stored in different populations of neurons and neuron subtypes.
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Affiliation(s)
- Nicole E Niewinski
- Department of Physiology and Pharmacology, Cumming School of Medicine, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Deyanell Hernandez
- Department of Physiology and Pharmacology, Cumming School of Medicine, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Michael A Colicos
- Department of Physiology and Pharmacology, Cumming School of Medicine, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta T2N 4N1, Canada
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5
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Park S, Ko SY, Frankland PW, Josselyn SA. Comparing behaviours induced by natural memory retrieval and optogenetic reactivation of an engram ensemble in mice. Philos Trans R Soc Lond B Biol Sci 2024; 379:20230227. [PMID: 38853560 PMCID: PMC11343273 DOI: 10.1098/rstb.2023.0227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 03/06/2024] [Accepted: 04/09/2024] [Indexed: 06/11/2024] Open
Abstract
Memories are thought to be stored within sparse collections of neurons known as engram ensembles. Neurons active during a training episode are allocated to an engram ensemble ('engram neurons'). Memory retrieval is initiated by external sensory or internal cues present at the time of training reactivating engram neurons. Interestingly, optogenetic reactivation of engram ensemble neurons alone in the absence of external sensory cues is sufficient to induce behaviour consistent with memory retrieval in mice. However, there may exist differences between the behaviours induced by natural retrieval cues or artificial engram reactivation. Here, we compared two defensive behaviours (freezing and the syllable structure of ultrasonic vocalizations, USVs) induced by sensory cues present at training (natural memory retrieval) and optogenetic engram ensemble reactivation (artificial memory retrieval) in a threat conditioning paradigm in the same mice. During natural memory recall, we observed a strong positive correlation between freezing levels and distinct USV syllable features (characterized by an unsupervised algorithm, MUPET (Mouse Ultrasonic Profile ExTraction)). Moreover, we observed strikingly similar behavioural profiles in terms of freezing and USV characteristics between natural memory recall and artificial memory recall in the absence of sensory retrieval cues. Although our analysis focused on two behavioural measures of threat memory (freezing and USV characteristics), these results underscore the similarities between threat memory recall triggered naturally and through optogenetic reactivation of engram ensembles. This article is part of a discussion meeting issue 'Long-term potentiation: 50 years on'.
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Affiliation(s)
- Sungmo Park
- Program in Neurosciences and Mental Health, Hospital for Sick Children, 555 University Avenue, Toronto, OntarioM5G 1X8, Canada
| | - Sang Yoon Ko
- Program in Neurosciences and Mental Health, Hospital for Sick Children, 555 University Avenue, Toronto, OntarioM5G 1X8, Canada
- Department of Physiology, University of Toronto, Toronto, OntarioM5G 1X8, Canada
| | - Paul W. Frankland
- Program in Neurosciences and Mental Health, Hospital for Sick Children, 555 University Avenue, Toronto, OntarioM5G 1X8, Canada
- Department of Physiology, University of Toronto, Toronto, OntarioM5G 1X8, Canada
- Department of Psychology, University of Toronto, Toronto, OntarioM5G 1X8, Canada
| | - Sheena A. Josselyn
- Program in Neurosciences and Mental Health, Hospital for Sick Children, 555 University Avenue, Toronto, OntarioM5G 1X8, Canada
- Department of Physiology, University of Toronto, Toronto, OntarioM5G 1X8, Canada
- Department of Psychology, University of Toronto, Toronto, OntarioM5G 1X8, Canada
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6
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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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7
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Antonoudiou P, Stone BT, Colmers PLW, Evans-Strong A, Teboul E, Walton NL, Weiss GL, Maguire J. Experience-dependent information routing through the basolateral amygdala shapes behavioral outcomes. Cell Rep 2024; 43:114489. [PMID: 38990724 PMCID: PMC11330675 DOI: 10.1016/j.celrep.2024.114489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 05/22/2024] [Accepted: 06/25/2024] [Indexed: 07/13/2024] Open
Abstract
It is well established that the basolateral amygdala (BLA) is an emotional processing hub that governs a diverse repertoire of behaviors. Selective engagement of a heterogeneous cell population in the BLA is thought to contribute to this flexibility in behavioral outcomes. However, whether this process is impacted by previous experiences that influence emotional processing remains unclear. Here we demonstrate that previous positive (enriched environment [EE]) or negative (chronic unpredictable stress [CUS]) experiences differentially influence the activity of populations of BLA principal neurons projecting to either the nucleus accumbens core or bed nucleus of the stria terminalis. Chemogenetic manipulation of these projection-specific neurons can mimic or occlude the effects of CUS and EE on behavioral outcomes to bidirectionally control avoidance behaviors and stress-induced helplessness. These data demonstrate that previous experiences influence the responsiveness of projection-specific BLA principal neurons, biasing information routing through the BLA, to drive divergent behavioral outcomes.
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Affiliation(s)
- Pantelis Antonoudiou
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, USA
| | - Bradly T Stone
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, USA
| | - Phillip L W Colmers
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, USA
| | - Aidan Evans-Strong
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, USA
| | - Eric Teboul
- Neuroscience Program, Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, MA, USA
| | - Najah L Walton
- Neuroscience Program, Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, MA, USA
| | - Grant L Weiss
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, USA
| | - Jamie Maguire
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, USA.
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8
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Lohnas LJ, Howard MW. The influence of emotion on temporal context models. Cogn Emot 2024:1-29. [PMID: 39007902 DOI: 10.1080/02699931.2024.2371075] [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: 11/12/2023] [Accepted: 06/17/2024] [Indexed: 07/16/2024]
Abstract
Temporal context models (TCMs) have been influential in understanding episodic memory and its neural underpinnings. Recently, TCMs have been extended to explain emotional memory effects, one of the most clinically important findings in the field of memory research. This review covers recent advances in hypotheses for the neural representation of spatiotemporal context through the lens of TCMs, including their ability to explain the influence of emotion on episodic and temporal memory. In recent years, simplifying assumptions of "classical" TCMs - with exponential trace decay and the mechanism by which temporal context is recovered - have become increasingly clear. The review also outlines how recent advances could be incorporated into a future TCM, beyond classical assumptions, to integrate emotional modulation.
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Affiliation(s)
- Lynn J Lohnas
- Department of Psychology, Syracuse University, Syracuse, NY, USA
| | - Marc W Howard
- Department of Psychological and Brain Sciences, Boston University, Boston, MA, USA
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9
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Guo X, Hong P, Xiong S, Yan Y, Xie H, Guan JS. Kdm4a is an activity downregulated barrier to generate engrams for memory separation. Nat Commun 2024; 15:5887. [PMID: 39003305 PMCID: PMC11246488 DOI: 10.1038/s41467-024-50218-y] [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: 12/20/2023] [Accepted: 07/01/2024] [Indexed: 07/15/2024] Open
Abstract
Memory engrams are a subset of learning activated neurons critical for memory recall, consolidation, extinction and separation. While the transcriptional profile of engrams after learning suggests profound neural changes underlying plasticity and memory formation, little is known about how memory engrams are selected and allocated. As epigenetic factors suppress memory formation, we developed a CRISPR screening in the hippocampus to search for factors controlling engram formation. We identified histone lysine-specific demethylase 4a (Kdm4a) as a negative regulator for engram formation. Kdm4a is downregulated after neural activation and controls the volume of mossy fiber boutons. Mechanistically, Kdm4a anchors to the exonic region of Trpm7 gene loci, causing the stalling of nascent RNAs and allowing burst transcription of Trpm7 upon the dismissal of Kdm4a. Furthermore, the YTH domain containing protein 2 (Ythdc2) recruits Kdm4a to the Trpm7 gene and stabilizes nascent RNAs. Reducing the expression of Kdm4a in the hippocampus via genetic manipulation or artificial neural activation facilitated the ability of pattern separation in rodents. Our work indicates that Kdm4a is a negative regulator of engram formation and suggests a priming state to generate a separate memory.
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Affiliation(s)
- Xiuxian Guo
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Pengfei Hong
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Songhai Xiong
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Yuze Yan
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Hong Xie
- Institute of Photonic Chips, School of Artificial Intelligence Science and Technology, University of Shanghai for Science and Technology, Shanghai, China.
| | - Ji-Song Guan
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China.
- State Key Laboratory of Advanced Medical Materials and Devices, ShanghaiTech University, Shanghai, China.
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10
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Shakhawat AMD, Foltz JG, Nance AB, Bhateja J, Raymond JL. Systemic pharmacological suppression of neural activity reverses learning impairment in a mouse model of Fragile X syndrome. eLife 2024; 12:RP92543. [PMID: 38953282 PMCID: PMC11219043 DOI: 10.7554/elife.92543] [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] [Indexed: 07/03/2024] Open
Abstract
The enhancement of associative synaptic plasticity often results in impaired rather than enhanced learning. Previously, we proposed that such learning impairments can result from saturation of the plasticity mechanism (Nguyen-Vu et al., 2017), or, more generally, from a history-dependent change in the threshold for plasticity. This hypothesis was based on experimental results from mice lacking two class I major histocompatibility molecules, MHCI H2-Kb and H2-Db (MHCI KbDb-/-), which have enhanced associative long-term depression at the parallel fiber-Purkinje cell synapses in the cerebellum (PF-Purkinje cell LTD). Here, we extend this work by testing predictions of the threshold metaplasticity hypothesis in a second mouse line with enhanced PF-Purkinje cell LTD, the Fmr1 knockout mouse model of Fragile X syndrome (FXS). Mice lacking Fmr1 gene expression in cerebellar Purkinje cells (L7-Fmr1 KO) were selectively impaired on two oculomotor learning tasks in which PF-Purkinje cell LTD has been implicated, with no impairment on LTD-independent oculomotor learning tasks. Consistent with the threshold metaplasticity hypothesis, behavioral pre-training designed to reverse LTD at the PF-Purkinje cell synapses eliminated the oculomotor learning deficit in the L7-Fmr1 KO mice, as previously reported in MHCI KbDb-/-mice. In addition, diazepam treatment to suppress neural activity and thereby limit the induction of associative LTD during the pre-training period also eliminated the learning deficits in L7-Fmr1 KO mice. These results support the hypothesis that cerebellar LTD-dependent learning is governed by an experience-dependent sliding threshold for plasticity. An increased threshold for LTD in response to elevated neural activity would tend to oppose firing rate stability, but could serve to stabilize synaptic weights and recently acquired memories. The metaplasticity perspective could inform the development of new clinical approaches for addressing learning impairments in autism and other disorders of the nervous system.
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Affiliation(s)
- Amin MD Shakhawat
- Department of Neurobiology, Stanford UniversityStanfordUnited States
| | | | - Adam B Nance
- Department of Neurobiology, Stanford UniversityStanfordUnited States
| | - Jaydev Bhateja
- Department of Neurobiology, Stanford UniversityStanfordUnited States
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11
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Cui K, Qi X, Liu Z, Sun W, Jiao P, Liu C, Tong J, Sun X, Sun H, Fu S, Wang J, Zheng Y, Liu T, Cui S, Liu F, Mao J, Zheng J, Wan Y, Yi M. Dominant activities of fear engram cells in the dorsal dentate gyrus underlie fear generalization in mice. PLoS Biol 2024; 22:e3002679. [PMID: 38995985 PMCID: PMC11244812 DOI: 10.1371/journal.pbio.3002679] [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: 10/18/2023] [Accepted: 05/16/2024] [Indexed: 07/14/2024] Open
Abstract
Over-generalized fear is a maladaptive response to harmless stimuli or situations characteristic of posttraumatic stress disorder (PTSD) and other anxiety disorders. The dorsal dentate gyrus (dDG) contains engram cells that play a crucial role in accurate memory retrieval. However, the coordination mechanism of neuronal subpopulations within the dDG network during fear generalization is not well understood. Here, with the Tet-off system combined with immunostaining and two-photon calcium imaging, we report that dDG fear engram cells labeled in the conditioned context constitutes a significantly higher proportion of dDG neurons activated in a similar context where mice show generalized fear. The activation of these dDG fear engram cells encoding the conditioned context is both sufficient and necessary for inducing fear generalization in the similar context. Activities of mossy cells in the ventral dentate gyrus (vMCs) are significantly suppressed in mice showing fear generalization in a similar context, and activating the vMCs-dDG pathway suppresses generalized but not conditioned fear. Finally, modifying fear memory engrams in the dDG with "safety" signals effectively rescues fear generalization. These findings reveal that the competitive advantage of dDG engram cells underlies fear generalization, which can be rescued by activating the vMCs-dDG pathway or modifying fear memory engrams, and provide novel insights into the dDG network as the neuronal basis of fear generalization.
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Affiliation(s)
- Kun Cui
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing, China
- Beijing Life Science Academy, Beijing, China
| | - Xuetao Qi
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Zilong Liu
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Weiqi Sun
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Peijie Jiao
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Chang Liu
- Beijing Life Science Academy, Beijing, China
| | - Jifu Tong
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Xiaoyan Sun
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Haojie Sun
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing, China
- UCL School of Pharmacy, University College London, London, United Kingdom
| | - Su Fu
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Jiaxin Wang
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Yawen Zheng
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Tianyu Liu
- Department of Anesthesiology, Peking University People's Hospital, Beijing, China
| | - Shuang Cui
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing, China
- Key Laboratory for Neuroscience, Ministry of Education/National Health Commission, Peking University, Beijing, China
| | - Fengyu Liu
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing, China
- Key Laboratory for Neuroscience, Ministry of Education/National Health Commission, Peking University, Beijing, China
| | - Jian Mao
- Beijing Life Science Academy, Beijing, China
| | - Jie Zheng
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing, China
- Key Laboratory for Neuroscience, Ministry of Education/National Health Commission, Peking University, Beijing, China
| | - You Wan
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing, China
- Beijing Life Science Academy, Beijing, China
- Key Laboratory for Neuroscience, Ministry of Education/National Health Commission, Peking University, Beijing, China
- Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Ming Yi
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Peking University, Beijing, China
- Key Laboratory for Neuroscience, Ministry of Education/National Health Commission, Peking University, Beijing, China
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12
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Abatis M, Perin R, Niu R, van den Burg E, Hegoburu C, Kim R, Okamura M, Bito H, Markram H, Stoop R. Fear learning induces synaptic potentiation between engram neurons in the rat lateral amygdala. Nat Neurosci 2024; 27:1309-1317. [PMID: 38871992 PMCID: PMC11239494 DOI: 10.1038/s41593-024-01676-6] [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: 06/29/2023] [Accepted: 05/07/2024] [Indexed: 06/15/2024]
Abstract
The lateral amygdala (LA) encodes fear memories by potentiating sensory inputs associated with threats and, in the process, recruits 10-30% of its neurons per fear memory engram. However, how the local network within the LA processes this information and whether it also plays a role in storing it are still largely unknown. Here, using ex vivo 12-patch-clamp and in vivo 32-electrode electrophysiological recordings in the LA of fear-conditioned rats, in combination with activity-dependent fluorescent and optogenetic tagging and recall, we identified a sparsely connected network between principal LA neurons that is organized in clusters. Fear conditioning specifically causes potentiation of synaptic connections between learning-recruited neurons. These findings of synaptic plasticity in an autoassociative excitatory network of the LA may suggest a basic principle through which a small number of pyramidal neurons could encode a large number of memories.
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Affiliation(s)
- Marios Abatis
- Department of Psychiatry, Center for Psychiatric Neuroscience, University Hospital of Lausanne, Prilly-Lausanne, Switzerland
| | - Rodrigo Perin
- Brain-Mind Institute, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Ruifang Niu
- Department of Psychiatry, Center for Psychiatric Neuroscience, University Hospital of Lausanne, Prilly-Lausanne, Switzerland
| | - Erwin van den Burg
- Department of Psychiatry, Center for Psychiatric Neuroscience, University Hospital of Lausanne, Prilly-Lausanne, Switzerland
| | - Chloe Hegoburu
- Department of Psychiatry, Center for Psychiatric Neuroscience, University Hospital of Lausanne, Prilly-Lausanne, Switzerland
| | - Ryang Kim
- Department of Neurochemistry, The University of Tokyo Graduate School of Medicine, Tokyo, Japan
| | - Michiko Okamura
- Department of Neurochemistry, The University of Tokyo Graduate School of Medicine, Tokyo, Japan
| | - Haruhiko Bito
- Department of Neurochemistry, The University of Tokyo Graduate School of Medicine, Tokyo, Japan
| | - Henry Markram
- Brain-Mind Institute, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Ron Stoop
- Department of Psychiatry, Center for Psychiatric Neuroscience, University Hospital of Lausanne, Prilly-Lausanne, Switzerland.
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13
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Choucry A, Nomoto M, Inokuchi K. Engram mechanisms of memory linking and identity. Nat Rev Neurosci 2024; 25:375-392. [PMID: 38664582 DOI: 10.1038/s41583-024-00814-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/25/2024] [Indexed: 05/25/2024]
Abstract
Memories are thought to be stored in neuronal ensembles referred to as engrams. Studies have suggested that when two memories occur in quick succession, a proportion of their engrams overlap and the memories become linked (in a process known as prospective linking) while maintaining their individual identities. In this Review, we summarize the key principles of memory linking through engram overlap, as revealed by experimental and modelling studies. We describe evidence of the involvement of synaptic memory substrates, spine clustering and non-linear neuronal capacities in prospective linking, and suggest a dynamic somato-synaptic model, in which memories are shared between neurons yet remain separable through distinct dendritic and synaptic allocation patterns. We also bring into focus retrospective linking, in which memories become associated after encoding via offline reactivation, and discuss key temporal and mechanistic differences between prospective and retrospective linking, as well as the potential differences in their cognitive outcomes.
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Affiliation(s)
- Ali Choucry
- Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
- Research Center for Idling Brain Science, University of Toyama, Toyama, Japan
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Cairo University, Cairo, Egypt
| | - Masanori Nomoto
- Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
- Research Center for Idling Brain Science, University of Toyama, Toyama, Japan
- CREST, Japan Science and Technology Agency (JST), University of Toyama, Toyama, Japan
- Japan Agency for Medical Research and Development (AMED), Tokyo, Japan
| | - Kaoru Inokuchi
- Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan.
- Research Center for Idling Brain Science, University of Toyama, Toyama, Japan.
- CREST, Japan Science and Technology Agency (JST), University of Toyama, Toyama, Japan.
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14
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Concina G, Milano L, Renna A, Manassero E, Stabile F, Sacchetti B. Hippocampus-to-amygdala pathway drives the separation of remote memories of related events. Cell Rep 2024; 43:114151. [PMID: 38656872 DOI: 10.1016/j.celrep.2024.114151] [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: 05/24/2023] [Revised: 02/21/2024] [Accepted: 04/09/2024] [Indexed: 04/26/2024] Open
Abstract
The mammalian brain can store and retrieve memories of related events as distinct memories and remember common features of those experiences. How it computes this function remains elusive. Here, we show in rats that recent memories of two closely timed auditory fear events share overlapping neuronal ensembles in the basolateral amygdala (BLA) and are functionally linked. However, remote memories have reduced neuronal overlap and are functionally independent. The activity of parvalbumin (PV)-expressing neurons in the BLA plays a crucial role in forming separate remote memories. Chemogenetic blockade of PV preserves individual remote memories but prevents their segregation, resulting in reciprocal associations. The hippocampus drives this process through specific excitatory connections with BLA GABAergic interneurons. These findings provide insights into the neuronal mechanisms that minimize the overlap between distinct remote memories and enable the retrieval of related memories separately.
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Affiliation(s)
- Giulia Concina
- Rita Levi-Montalcini Department of Neuroscience, University of Turin, 10125 Turin, Italy
| | - Luisella Milano
- Rita Levi-Montalcini Department of Neuroscience, University of Turin, 10125 Turin, Italy
| | - Annamaria Renna
- Rita Levi-Montalcini Department of Neuroscience, University of Turin, 10125 Turin, Italy
| | - Eugenio Manassero
- Rita Levi-Montalcini Department of Neuroscience, University of Turin, 10125 Turin, Italy
| | - Francesca Stabile
- Rita Levi-Montalcini Department of Neuroscience, University of Turin, 10125 Turin, Italy
| | - Benedetto Sacchetti
- Rita Levi-Montalcini Department of Neuroscience, University of Turin, 10125 Turin, Italy.
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15
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Zhou Y, Wang JL, Qiu L, Torpey J, Wixson JG, Lyon M, Chen X. NMDA Receptors Control Activity Hierarchy in Neural Network: Loss of Control in Hierarchy Leads to Learning Impairments, Dissociation, and Psychosis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.01.06.523038. [PMID: 36712055 PMCID: PMC9881912 DOI: 10.1101/2023.01.06.523038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
While it is known that associative memory is preferentially encoded by memory-eligible "primed" neurons, in vivo neural activity hierarchy has not been quantified and little is known about how such a hierarchy is established. Leveraging in vivo calcium imaging of hippocampal neurons on freely behaving mice, we developed the first method to quantify real-time neural activity hierarchy in the CA1 region. Neurons on the top of activity hierarchy are identified as primed neurons. In cilia knockout mice that exhibit severe learning deficits, the percentage of primed neurons is drastically reduced. We developed a simplified neural network model that incorporates simulations of linear and non-linear weighted components, modeling the synaptic ionic conductance of AMPA and NMDA receptors, respectively. We found that moderate non-linear to linear conductance ratios naturally leads a small fraction of neurons to be primed in the simulated neural network. Removal of the non-linear component eliminates the existing activity hierarchy and reinstate it to the network stochastically primes a new pool of neurons. Blockade of NMDA receptors by ketamine not only decreases general neuronal activity causing learning impairments, but also disrupts neural activity hierarchy. Additionally, ketamine-induced super-synchronized slow oscillation during anesthesia can be simulated if the non-linear NMDAR component is removed to flatten activity hierarchy. Together, this study develops a unique method to measure neural activity hierarchy and identifies NMDA receptors as a key factor that controls the hierarchy. It presents the first evidence suggesting that hierarchy disruption by NMDAR blockade causes dissociation and psychosis.
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16
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Vazquez K, Cole KE, Parsons RG. Sex and the facilitation of cued fear by prior contextual fear conditioning in rats. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.23.595599. [PMID: 38826383 PMCID: PMC11142181 DOI: 10.1101/2024.05.23.595599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
Previous studies have shown that the formation of new memories can be influenced by prior experience. This includes work using pavlovian fear conditioning in rodents that have shown that an initial fear conditioning experience can become associated with and facilitate the acquisition of new fear memories, especially when they occur close together in time. However, most of the prior studies used only males as subjects resulting in questions about the generalizability of the findings from this work. Here we tested whether prior contextual fear conditioning would facilitate later learning of cued fear conditioning in both male and female rats, and if there were differences based on the interval between the two conditioning episodes. Our results showed that levels of cued fear were not influenced by prior contextual fear conditioning or by the interval between training, however, females showed lower levels of cued fear. Freezing behavior in the initial training context differed by sex, with females showing lower levels of contextual fear, and by the type of initial training, with rats given delayed shock showing higher levels of fear than rats given immediate shock during contextual fear conditioning. These results indicate that contextual fear conditioning does not prime subsequent cued fear conditioning and that female rats express lower levels of cued and contextual fear conditioning than males.
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Affiliation(s)
- Katherine Vazquez
- Stony Brook University, Department of Psychology, 100 Nicolls Rd., Stony Brook, NY, 11794
| | - Kehinde E Cole
- Stony Brook University, Department of Psychology, 100 Nicolls Rd., Stony Brook, NY, 11794
| | - Ryan G Parsons
- Stony Brook University, Department of Psychology, 100 Nicolls Rd., Stony Brook, NY, 11794
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17
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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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18
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Delamare G, Zaki Y, Cai DJ, Clopath C. Drift of neural ensembles driven by slow fluctuations of intrinsic excitability. eLife 2024; 12:RP88053. [PMID: 38712831 DOI: 10.7554/elife.88053] [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] [Indexed: 05/08/2024] Open
Abstract
Representational drift refers to the dynamic nature of neural representations in the brain despite the behavior being seemingly stable. Although drift has been observed in many different brain regions, the mechanisms underlying it are not known. Since intrinsic neural excitability is suggested to play a key role in regulating memory allocation, fluctuations of excitability could bias the reactivation of previously stored memory ensembles and therefore act as a motor for drift. Here, we propose a rate-based plastic recurrent neural network with slow fluctuations of intrinsic excitability. We first show that subsequent reactivations of a neural ensemble can lead to drift of this ensemble. The model predicts that drift is induced by co-activation of previously active neurons along with neurons with high excitability which leads to remodeling of the recurrent weights. Consistent with previous experimental works, the drifting ensemble is informative about its temporal history. Crucially, we show that the gradual nature of the drift is necessary for decoding temporal information from the activity of the ensemble. Finally, we show that the memory is preserved and can be decoded by an output neuron having plastic synapses with the main region.
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Affiliation(s)
- Geoffroy Delamare
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Yosif Zaki
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, United States
| | - Denise J Cai
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, United States
| | - Claudia Clopath
- Department of Bioengineering, Imperial College London, London, United Kingdom
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19
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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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20
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Loetscher KB, Goldfarb EV. Integrating and fragmenting memories under stress and alcohol. Neurobiol Stress 2024; 30:100615. [PMID: 38375503 PMCID: PMC10874731 DOI: 10.1016/j.ynstr.2024.100615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 02/03/2024] [Accepted: 02/06/2024] [Indexed: 02/21/2024] Open
Abstract
Stress can powerfully influence the way we form memories, particularly the extent to which they are integrated or situated within an underlying spatiotemporal and broader knowledge architecture. These different representations in turn have significant consequences for the way we use these memories to guide later behavior. Puzzlingly, although stress has historically been argued to promote fragmentation, leading to disjoint memory representations, more recent work suggests that stress can also facilitate memory binding and integration. Understanding the circumstances under which stress fosters integration will be key to resolving this discrepancy and unpacking the mechanisms by which stress can shape later behavior. Here, we examine memory integration at multiple levels: linking together the content of an individual experience, threading associations between related but distinct events, and binding an experience into a pre-existing schema or sense of causal structure. We discuss neural and cognitive mechanisms underlying each form of integration as well as findings regarding how stress, aversive learning, and negative affect can modulate each. In this analysis, we uncover that stress can indeed promote each level of integration. We also show how memory integration may apply to understanding effects of alcohol, highlighting extant clinical and preclinical findings and opportunities for further investigation. Finally, we consider the implications of integration and fragmentation for later memory-guided behavior, and the importance of understanding which type of memory representation is potentiated in order to design appropriate interventions.
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Affiliation(s)
| | - Elizabeth V. Goldfarb
- Department of Psychiatry, Yale University, USA
- Department of Psychology, Yale University, USA
- Wu Tsai Institute, Yale University, USA
- National Center for PTSD, West Haven VA, USA
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21
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Luft JG, Popik B, Gonçalves DA, Cruz FC, de Oliveira Alvares L. Distinct engrams control fear and extinction memory. Hippocampus 2024; 34:230-240. [PMID: 38396226 DOI: 10.1002/hipo.23601] [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: 09/20/2023] [Revised: 12/06/2023] [Accepted: 02/04/2024] [Indexed: 02/25/2024]
Abstract
Memories are stored in engram cells, which are necessary and sufficient for memory recall. Recalling a memory might undergo reconsolidation or extinction. It has been suggested that the original memory engram is reactivated during reconsolidation so that memory can be updated. Conversely, during extinction training, a new memory is formed that suppresses the original engram. Nonetheless, it is unknown whether extinction creates a new engram or modifies the original fear engram. In this study, we utilized the Daun02 procedure, which uses c-Fos-lacZ rats to induce apoptosis of strongly activated neurons and examine whether a new memory trace emerges as a result of a short or long reactivation, or if these processes rely on modifications within the original engram located in the basolateral amygdala (BLA) and infralimbic (IL) cortex. By eliminating neurons activated during consolidation and reactivation, we observed significant impacts on fear memory, highlighting the importance of the BLA engram in these processes. Although we were unable to show any impact when removing the neurons activated after the test of a previously extinguished memory in the BLA, disrupting the IL extinction engram reactivated the aversive memory that was suppressed by the extinction memory. Thus, we demonstrated that the IL cortex plays a crucial role in the network involved in extinction, and disrupting this specific node alone is sufficient to impair extinction behavior. Additionally, our findings indicate that extinction memories rely on the formation of a new memory, supporting the theory that extinction memories rely on the formation of a new memory, whereas the reconsolidation process reactivates the same original memory trace.
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Affiliation(s)
- Jordana Griebler Luft
- Laboratório de Neurobiologia da Memória, Departamento de Biofísica, Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Bruno Popik
- Laboratório de Neurobiologia da Memória, Departamento de Biofísica, Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Débora Aguirre Gonçalves
- Laboratório de Neurobiologia da Memória, Departamento de Biofísica, Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Fabio Cardoso Cruz
- Departamento de Farmacologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Lucas de Oliveira Alvares
- Laboratório de Neurobiologia da Memória, Departamento de Biofísica, Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
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22
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Park H, Kaang BK. Memory allocation at the neuronal and synaptic levels. BMB Rep 2024; 57:176-181. [PMID: 37964638 PMCID: PMC11058361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 10/05/2023] [Accepted: 11/10/2023] [Indexed: 11/16/2023] Open
Abstract
Memory allocation, which determines where memories are stored in specific neurons or synapses, has consistently been demonstrated to occur via specific mechanisms. Neuronal allocation studies have focused on the activated population of neurons and have shown that increased excitability via cAMP response element-binding protein (CREB) induces a bias toward memoryencoding neurons. Synaptic allocation suggests that synaptic tagging enables memory to be mediated through different synaptic strengthening mechanisms, even within a single neuron. In this review, we summarize the fundamental concepts of memory allocation at the neuronal and synaptic levels and discuss their potential interrelationships. [BMB Reports 2024; 57(4): 176-181].
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Affiliation(s)
- HyoJin Park
- Center for Cognition and Sociality, Life Science Institute, Institute for Basic Science (IBS), Daejeon 34126, Korea
- Department of Biological Science, Seoul National University, Seoul 08826, Korea
| | - Bong-Kiun Kaang
- Center for Cognition and Sociality, Life Science Institute, Institute for Basic Science (IBS), Daejeon 34126, Korea
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23
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Durán Laforet V, Schafer DP. Microglia: Activity-dependent regulators of neural circuits. Ann N Y Acad Sci 2024; 1533:38-50. [PMID: 38294960 PMCID: PMC10976428 DOI: 10.1111/nyas.15105] [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] [Indexed: 02/02/2024]
Abstract
It has been more than a century since Pío del Río-Hortega first characterized microglia in histological stains of brain tissue. Since then, significant advances have been made in understanding the role of these resident central nervous system (CNS) macrophages. In particular, it is now known that microglia can sense neural activity and modulate neuronal circuits accordingly. We review the mechanisms by which microglia detect changes in neural activity to then modulate synapse numbers in the developing and mature CNS. This includes responses to both spontaneous and experience-driven neural activity. We further discuss activity-dependent mechanisms by which microglia regulate synaptic function and neural circuit excitability. Together, our discussion provides a comprehensive review of the activity-dependent functions of microglia within neural circuits in the healthy CNS, and highlights exciting new open questions related to understanding more fully microglia as key components and regulators of neural circuits.
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Affiliation(s)
- Violeta Durán Laforet
- Department of Neurobiology, Brudnick Neuropsychiatric Research Institute, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
| | - Dorothy P Schafer
- Department of Neurobiology, Brudnick Neuropsychiatric Research Institute, University of Massachusetts Chan Medical School, Worcester, Massachusetts, USA
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24
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Sladky R, Kargl D, Haubensak W, Lamm C. An active inference perspective for the amygdala complex. Trends Cogn Sci 2024; 28:223-236. [PMID: 38103984 DOI: 10.1016/j.tics.2023.11.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 11/14/2023] [Accepted: 11/16/2023] [Indexed: 12/19/2023]
Abstract
The amygdala is a heterogeneous network of subcortical nuclei with central importance in cognitive and clinical neuroscience. Various experimental designs in human psychology and animal model research have mapped multiple conceptual frameworks (e.g., valence/salience and decision making) to ever more refined amygdala circuitry. However, these predominantly bottom up-driven accounts often rely on interpretations tailored to a specific phenomenon, thus preventing comprehensive and integrative theories. We argue here that an active inference model of amygdala function could unify these fractionated approaches into an overarching framework for clearer empirical predictions and mechanistic interpretations. This framework embeds top-down predictive models, informed by prior knowledge and belief updating, within a dynamical system distributed across amygdala circuits in which self-regulation is implemented by continuously tracking environmental and homeostatic demands.
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Affiliation(s)
- Ronald Sladky
- Social, Cognitive, and Affective Neuroscience Unit, Department of Cognition, Emotion, and Methods in Psychology, Faculty of Psychology, University of Vienna, Liebiggasse 5, 1010 Vienna, Austria; Vienna Cognitive Science Hub, University of Vienna, 1010 Vienna, Austria.
| | - Dominic Kargl
- Department of Neuronal Cell Biology, Center for Brain Research, Medical University of Vienna, Spitalgasse 4, 1090 Vienna, Austria
| | - Wulf Haubensak
- Department of Neuronal Cell Biology, Center for Brain Research, Medical University of Vienna, Spitalgasse 4, 1090 Vienna, Austria; Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Campus Vienna Biocenter 1, 1030 Vienna, Austria
| | - Claus Lamm
- Social, Cognitive, and Affective Neuroscience Unit, Department of Cognition, Emotion, and Methods in Psychology, Faculty of Psychology, University of Vienna, Liebiggasse 5, 1010 Vienna, Austria; Vienna Cognitive Science Hub, University of Vienna, 1010 Vienna, Austria
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25
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Leake J, Cardona LS, Mencevski F, Westbrook RF, Holmes NM. Context and Time Regulate Fear Memory Consolidation and Reconsolidation in the Basolateral Amygdala Complex. J Neurosci 2024; 44:e1698232023. [PMID: 38286626 PMCID: PMC10904089 DOI: 10.1523/jneurosci.1698-23.2023] [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: 09/10/2023] [Revised: 10/31/2023] [Accepted: 11/08/2023] [Indexed: 01/31/2024] Open
Abstract
It is widely accepted that fear memories are consolidated through protein synthesis-dependent changes in the basolateral amygdala complex (BLA). However, recent studies show that protein synthesis is not required to consolidate the memory of a new dangerous experience when it is similar to a prior experience. Here, we examined whether the protein synthesis requirement for consolidating the new experience varies with its spatial and temporal distance from the prior experience. Female and male rats were conditioned to fear a stimulus (S1, e.g., light) paired with shock in stage 1 and a second stimulus (S2, e.g., tone) that preceded additional S1-shock pairings (S2-S1-shock) in stage 2. The latter stage was followed by a BLA infusion of a protein synthesis inhibitor, cycloheximide, or vehicle. Subsequent testing with S2 revealed that protein synthesis in the BLA was not required to consolidate fear to S2 when the training stages occurred 48 h apart in the same context; was required when they were separated by 14 d or occurred in different contexts; but was again not required if S1 was re-presented after the delay or in the different context. Similarly, protein synthesis in the BLA was not required to reconsolidate fear to S2 when the training stages occurred 48 h apart but was required when they occurred 14 d apart. Thus, the protein synthesis requirement for consolidating/reconsolidating fear memories in the BLA is determined by similarity between present and past experiences, the time and place in which they occur, and reminders of the past experiences.
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Affiliation(s)
- Jessica Leake
- School of Psychology, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Luisa Saavedra Cardona
- School of Psychology, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Filip Mencevski
- School of Psychology, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - R Frederick Westbrook
- School of Psychology, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Nathan M Holmes
- School of Psychology, University of New South Wales, Sydney, New South Wales 2052, Australia
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26
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Rajebhosale P, Ananth MR, Kim R, Crouse R, Jiang L, López-Hernández G, Zhong C, Arty C, Wang S, Jone A, Desai NS, Li Y, Picciotto MR, Role LW, Talmage DA. Functionally refined encoding of threat memory by distinct populations of basal forebrain cholinergic projection neurons. eLife 2024; 13:e86581. [PMID: 38363713 DOI: 10.7554/elife.86581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 02/14/2024] [Indexed: 02/18/2024] Open
Abstract
Neurons of the basal forebrain nucleus basalis and posterior substantia innominata (NBM/SIp) comprise the major source of cholinergic input to the basolateral amygdala (BLA). Using a genetically encoded acetylcholine (ACh) sensor in mice, we demonstrate that BLA-projecting cholinergic neurons can 'learn' the association between a naive tone and a foot shock (training) and release ACh in the BLA in response to the conditioned tone 24 hr later (recall). In the NBM/SIp cholinergic neurons express the immediate early gene, Fos following both training and memory recall. Cholinergic neurons that express Fos following memory recall display increased intrinsic excitability. Chemogenetic silencing of these learning-activated cholinergic neurons prevents expression of the defensive behavior to the tone. In contrast, we show that NBM/SIp cholinergic neurons are not activated by an innately threatening stimulus (predator odor). Instead, VP/SIa cholinergic neurons are activated and contribute to defensive behaviors in response to predator odor, an innately threatening stimulus. Taken together, we find that distinct populations of cholinergic neurons are recruited to signal distinct aversive stimuli, demonstrating functionally refined organization of specific types of memory within the cholinergic basal forebrain of mice.
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Affiliation(s)
| | - Mala R Ananth
- National Institute of Neurological Disorders and Stroke, NIH, Bethesda, United States
| | - Ronald Kim
- National Institute of Neurological Disorders and Stroke, NIH, Bethesda, United States
| | - Richard Crouse
- Yale Interdepartmental Neuroscience Program, Yale University, New Haven, United States
| | - Li Jiang
- National Institute of Neurological Disorders and Stroke, NIH, Bethesda, United States
| | | | - Chongbo Zhong
- National Institute of Neurological Disorders and Stroke, NIH, Bethesda, United States
| | | | - Shaohua Wang
- National Institute of Environmental Health Sciences, Durham, United States
| | - Alice Jone
- Program in Neuroscience, Stony Brook University, Stony Brook, United States
| | - Niraj S Desai
- National Institute of Neurological Disorders and Stroke, NIH, Bethesda, United States
| | - Yulong Li
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing, China
- PKU-IDG/McGovern Institute for Brain Research, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Marina R Picciotto
- Yale Interdepartmental Neuroscience Program, Yale University, New Haven, United States
- Department of Psychiatry, Yale University, New Haven, United States
| | - Lorna W Role
- National Institute of Neurological Disorders and Stroke, NIH, Bethesda, United States
| | - David A Talmage
- National Institute of Neurological Disorders and Stroke, NIH, Bethesda, United States
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27
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Grella SL, Donaldson TN. Contextual memory engrams, and the neuromodulatory influence of the locus coeruleus. Front Mol Neurosci 2024; 17:1342622. [PMID: 38375501 PMCID: PMC10875109 DOI: 10.3389/fnmol.2024.1342622] [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: 11/22/2023] [Accepted: 01/19/2024] [Indexed: 02/21/2024] Open
Abstract
Here, we review the basis of contextual memory at a conceptual and cellular level. We begin with an overview of the philosophical foundations of traversing space, followed by theories covering the material bases of contextual representations in the hippocampus (engrams), exploring functional characteristics of the cells and subfields within. Next, we explore various methodological approaches for investigating contextual memory engrams, emphasizing plasticity mechanisms. This leads us to discuss the role of neuromodulatory inputs in governing these dynamic changes. We then outline a recent hypothesis involving noradrenergic and dopaminergic projections from the locus coeruleus (LC) to different subregions of the hippocampus, in sculpting contextual representations, giving a brief description of the neuroanatomical and physiological properties of the LC. Finally, we examine how activity in the LC influences contextual memory processes through synaptic plasticity mechanisms to alter hippocampal engrams. Overall, we find that phasic activation of the LC plays an important role in promoting new learning and altering mnemonic processes at the behavioral and cellular level through the neuromodulatory influence of NE/DA in the hippocampus. These findings may provide insight into mechanisms of hippocampal remapping and memory updating, memory processes that are potentially dysregulated in certain psychiatric and neurodegenerative disorders.
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Affiliation(s)
- Stephanie L. Grella
- MNEME Lab, Department of Psychology, Program in Neuroscience, Loyola University Chicago, Chicago, IL, United States
| | - Tia N. Donaldson
- Systems Neuroscience and Behavior Lab, Department of Psychology, The University of New Mexico, Albuquerque, NM, United States
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28
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Jung H, Han D, Lee C, Kaang BK. Synaptic Engram. ADVANCES IN NEUROBIOLOGY 2024; 38:131-145. [PMID: 39008014 DOI: 10.1007/978-3-031-62983-9_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/16/2024]
Abstract
The concept of the engram refers to structural and/or physiological changes that underlie memory associations during learning. However, the precise biological basis of the engram remains elusive, with ongoing controversy regarding whether it resides at the cellular level or within the synaptic connections between activated cells. Here, we briefly review the studies investigating the cellular engram and the challenges they encounter. Subsequently, we delve into the biological basis of the engram within synaptic connections. In this regard, we introduce the history of synaptic engrams and discuss recent findings suggesting that synaptic plasticity serves as a substrate for memory. Additionally, we provide an overview of key technologies utilized in the study of synaptic plasticity.
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Affiliation(s)
- Hyunsu Jung
- Center for Cognition and Sociality, Life Science Institute, Institute for Basic Science (IBS), Daejeon, South Korea
- Interdisciplinary Program in Neuroscience, College of Natural Sciences, Seoul National University, Seoul, South Korea
| | - Daehee Han
- Center for Cognition and Sociality, Life Science Institute, Institute for Basic Science (IBS), Daejeon, South Korea
- Interdisciplinary Program in Neuroscience, College of Natural Sciences, Seoul National University, Seoul, South Korea
| | - Chaery Lee
- Center for Cognition and Sociality, Life Science Institute, Institute for Basic Science (IBS), Daejeon, South Korea
- Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul, South Korea
| | - Bong-Kiun Kaang
- Center for Cognition and Sociality, Life Science Institute, Institute for Basic Science (IBS), Daejeon, South Korea.
- Interdisciplinary Program in Neuroscience, College of Natural Sciences, Seoul National University, Seoul, South Korea.
- Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul, South Korea.
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29
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Fuentes-Ramos M, Barco Á. Unveiling Transcriptional and Epigenetic Mechanisms Within Engram Cells: Insights into Memory Formation and Stability. ADVANCES IN NEUROBIOLOGY 2024; 38:111-129. [PMID: 39008013 DOI: 10.1007/978-3-031-62983-9_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/16/2024]
Abstract
Memory traces for behavioral experiences, such as fear conditioning or taste aversion, are believed to be stored through biophysical and molecular changes in distributed neuronal ensembles across various brain regions. These ensembles are known as engrams, and the cells that constitute them are referred to as engram cells. Recent advancements in techniques for labeling and manipulating neural activity have facilitated the study of engram cells throughout different memory phases, including acquisition, allocation, long-term storage, retrieval, and erasure. In this chapter, we will explore the application of next-generation sequencing methods to engram research, shedding new light on the contribution of transcriptional and epigenetic mechanisms to engram formation and stability.
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Affiliation(s)
- Miguel Fuentes-Ramos
- Instituto de Neurociencias, Universidad Miguel Hernández - Consejo Superior de Investigaciones Científicas, Alicante, Spain
| | - Ángel Barco
- Instituto de Neurociencias, Universidad Miguel Hernández - Consejo Superior de Investigaciones Científicas, Alicante, Spain.
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30
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Jung JH, Wang Y, Rashid AJ, Zhang T, Frankland PW, Josselyn SA. Examining memory linking and generalization using scFLARE2, a temporally precise neuronal activity tagging system. Cell Rep 2023; 42:113592. [PMID: 38103203 PMCID: PMC10842737 DOI: 10.1016/j.celrep.2023.113592] [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: 08/28/2023] [Revised: 10/26/2023] [Accepted: 11/30/2023] [Indexed: 12/18/2023] Open
Abstract
How memories are organized in the brain influences whether they are remembered discretely versus linked with other experiences or whether generalized information is applied to entirely novel situations. Here, we used scFLARE2 (single-chain fast light- and activity-regulated expression 2), a temporally precise tagging system, to manipulate mouse lateral amygdala neurons active during one of two 3 min threat experiences occurring close (3 h) or further apart (27 h) in time. Silencing scFLARE2-tagged neurons showed that two threat experiences occurring at distal times are dis-allocated to orthogonal engram ensembles and remembered discretely, whereas the same two threat experiences occurring in close temporal proximity are linked via co-allocation to overlapping engram ensembles. Moreover, we found that co-allocation mediates memory generalization applied to a completely novel stimulus. These results indicate that endogenous temporal evolution of engram ensemble neuronal excitability determines how memories are organized and remembered and that this would not be possible using conventional immediate-early gene-based tagging methods.
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Affiliation(s)
- Jung Hoon Jung
- Program in Neurosciences & Mental Health, Hospital for Sick Children, 555 University Avenue, Toronto, ON M5G 1X8, Canada
| | - Ying Wang
- Program in Neurosciences & Mental Health, Hospital for Sick Children, 555 University Avenue, Toronto, ON M5G 1X8, Canada; Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Asim J Rashid
- Program in Neurosciences & Mental Health, Hospital for Sick Children, 555 University Avenue, Toronto, ON M5G 1X8, Canada
| | - Tao Zhang
- Program in Neurosciences & Mental Health, Hospital for Sick Children, 555 University Avenue, Toronto, ON M5G 1X8, Canada
| | - Paul W Frankland
- Program in Neurosciences & Mental Health, Hospital for Sick Children, 555 University Avenue, 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 Avenue, 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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31
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Khairinisa MA, Latarissa IR, Athaya NS, Charlie V, Musyaffa HA, Prasedya ES, Puspitasari IM. Potential Application of Marine Algae and Their Bioactive Metabolites in Brain Disease Treatment: Pharmacognosy and Pharmacology Insights for Therapeutic Advances. Brain Sci 2023; 13:1686. [PMID: 38137134 PMCID: PMC10741471 DOI: 10.3390/brainsci13121686] [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: 10/04/2023] [Revised: 11/04/2023] [Accepted: 12/05/2023] [Indexed: 12/24/2023] Open
Abstract
Seaweeds, also known as edible marine algae, are an abundant source of phytosterols, carotenoids, and polysaccharides, among other bioactive substances. Studies conducted in the past few decades have demonstrated that substances derived from seaweed may be able to pass through the blood-brain barrier and act as neuroprotectants. According to preliminary clinical research, seaweed may also help prevent or lessen the symptoms of cerebrovascular illnesses by reducing mental fatigue, preventing endothelial damage to the vascular wall of brain vessels, and regulating internal pressure. They have the ability to control neurotransmitter levels, lessen neuroinflammation, lessen oxidative stress, and prevent the development of amyloid plaques. This review aims to understand the application potential of marine algae and their influence on brain development, highlighting the nutritional value of this "superfood" and providing current knowledge on the molecular mechanisms in the brain associated with their dietary introduction.
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Affiliation(s)
- Miski Aghnia Khairinisa
- Department of Pharmacology and Clinical Pharmacy, Faculty of Pharmacy, Padjadjaran University, Sumedang 45363, Indonesia; (I.R.L.); (N.S.A.); (V.C.); (H.A.M.); (I.M.P.)
- Centre of Excellence in Pharmaceutical Care Innovation, Padjadjaran University, Sumedang 45363, Indonesia
| | - Irma Rahayu Latarissa
- Department of Pharmacology and Clinical Pharmacy, Faculty of Pharmacy, Padjadjaran University, Sumedang 45363, Indonesia; (I.R.L.); (N.S.A.); (V.C.); (H.A.M.); (I.M.P.)
| | - Nadiyah Salma Athaya
- Department of Pharmacology and Clinical Pharmacy, Faculty of Pharmacy, Padjadjaran University, Sumedang 45363, Indonesia; (I.R.L.); (N.S.A.); (V.C.); (H.A.M.); (I.M.P.)
| | - Vandie Charlie
- Department of Pharmacology and Clinical Pharmacy, Faculty of Pharmacy, Padjadjaran University, Sumedang 45363, Indonesia; (I.R.L.); (N.S.A.); (V.C.); (H.A.M.); (I.M.P.)
| | - Hanif Azhar Musyaffa
- Department of Pharmacology and Clinical Pharmacy, Faculty of Pharmacy, Padjadjaran University, Sumedang 45363, Indonesia; (I.R.L.); (N.S.A.); (V.C.); (H.A.M.); (I.M.P.)
| | - Eka Sunarwidhi Prasedya
- Department of Biology, Faculty of Mathematics and Natural Sciences, University of Mataram, Mataram 83115, Indonesia;
- Bioscience and Biotechnology Research Centre, Faculty of Mathematics and Natural Sciences, University of Mataram, Mataram 83126, Indonesia
| | - Irma Melyani Puspitasari
- Department of Pharmacology and Clinical Pharmacy, Faculty of Pharmacy, Padjadjaran University, Sumedang 45363, Indonesia; (I.R.L.); (N.S.A.); (V.C.); (H.A.M.); (I.M.P.)
- Centre of Excellence in Pharmaceutical Care Innovation, Padjadjaran University, Sumedang 45363, Indonesia
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32
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Hochgerner H, Singh S, Tibi M, Lin Z, Skarbianskis N, Admati I, Ophir O, Reinhardt N, Netser S, Wagner S, Zeisel A. Neuronal types in the mouse amygdala and their transcriptional response to fear conditioning. Nat Neurosci 2023; 26:2237-2249. [PMID: 37884748 PMCID: PMC10689239 DOI: 10.1038/s41593-023-01469-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 09/20/2023] [Indexed: 10/28/2023]
Abstract
The amygdala is a brain region primarily associated with emotional response. The use of genetic markers and single-cell transcriptomics can provide insights into behavior-associated cell state changes. Here we present a detailed cell-type taxonomy of the adult mouse amygdala during fear learning and memory consolidation. We perform single-cell RNA sequencing on naïve and fear-conditioned mice, identify 130 neuronal cell types and validate their spatial distributions. A subset of all neuronal types is transcriptionally responsive to fear learning and memory retrieval. The activated engram cells upregulate activity-response genes and coordinate the expression of genes associated with neurite outgrowth, synaptic signaling, plasticity and development. We identify known and previously undescribed candidate genes responsive to fear learning. Our molecular atlas may be used to generate hypotheses to unveil the neuron types and neural circuits regulating the emotional component of learning and memory.
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Affiliation(s)
- Hannah Hochgerner
- Faculty of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Haifa, Israel
| | - Shelly Singh
- Sagol Department of Neurobiology, University of Haifa, Haifa, Israel
| | - Muhammad Tibi
- Faculty of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Haifa, Israel
| | - Zhige Lin
- Faculty of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Haifa, Israel
| | - Niv Skarbianskis
- Faculty of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Haifa, Israel
| | - Inbal Admati
- Faculty of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Haifa, Israel
| | - Osnat Ophir
- Faculty of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Haifa, Israel
| | - Nuphar Reinhardt
- Faculty of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Haifa, Israel
| | - Shai Netser
- Sagol Department of Neurobiology, University of Haifa, Haifa, Israel
| | - Shlomo Wagner
- Sagol Department of Neurobiology, University of Haifa, Haifa, Israel
| | - Amit Zeisel
- Faculty of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Haifa, Israel.
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33
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Brosens N, Lesuis SL, Rao-Ruiz P, van den Oever MC, Krugers HJ. Shaping Memories Via Stress: A Synaptic Engram Perspective. Biol Psychiatry 2023:S0006-3223(23)01720-1. [PMID: 37977215 DOI: 10.1016/j.biopsych.2023.11.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 10/09/2023] [Accepted: 11/05/2023] [Indexed: 11/19/2023]
Abstract
Stress modulates the activity of various memory systems and can thereby guide behavioral interaction with the environment in an adaptive or maladaptive manner. At the cellular level, a large body of evidence indicates that (nor)adrenaline and glucocorticoid release induced by acute stress exposure affects synapse function and synaptic plasticity, which are critical substrates for learning and memory. Recent evidence suggests that memories are supported in the brain by sparsely distributed neurons within networks, termed engram cell ensembles. While the physiological and molecular effects of stress on the synapse are increasingly well characterized, how these synaptic modifications shape the multiscale dynamics of engram cell ensembles is still poorly understood. In this review, we discuss and integrate recent information on how acute stress affects synapse function and how this may alter engram cell ensembles and their synaptic connectivity to shape memory strength and memory precision. We provide a mechanistic framework of a synaptic engram under stress and put forward outstanding questions that address knowledge gaps in our understanding of the mechanisms that underlie stress-induced memory modulation.
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Affiliation(s)
- Niek Brosens
- Brain Plasticity Group, Swammerdam Institute for Life Sciences-Center for Neuroscience, University of Amsterdam, Amsterdam, the Netherlands.
| | - Sylvie L Lesuis
- Brain Plasticity Group, Swammerdam Institute for Life Sciences-Center for Neuroscience, University of Amsterdam, Amsterdam, the Netherlands; Cellular and Cognitive Neuroscience group, Swammerdam Institute for Life Sciences-Center for Neuroscience, University of Amsterdam, Amsterdam, the Netherlands
| | - Priyanka Rao-Ruiz
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Michel C van den Oever
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Harm J Krugers
- Brain Plasticity Group, Swammerdam Institute for Life Sciences-Center for Neuroscience, University of Amsterdam, Amsterdam, the Netherlands.
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34
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Cole KE, Parsons RG. Sex difference in the facilitation of fear learning by prior fear conditioning. Neurobiol Learn Mem 2023; 205:107835. [PMID: 37805117 DOI: 10.1016/j.nlm.2023.107835] [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: 06/12/2023] [Revised: 09/18/2023] [Accepted: 10/04/2023] [Indexed: 10/09/2023]
Abstract
There is now ample evidence that the strength and underlying mechanisms of memory formation can be drastically altered by prior experience. However, the prior work using rodent models on this topic has used only males as subjects, and as a result, we do know whether or not the effects of prior experience on subsequent learning are similar in both sexes. As a first step towards addressing this shortcoming, rats of both sexes were given auditory fear conditioning, or fear conditioning with unsignaled shocks, followed an hour or a day later by a single pairing of light and shock. Fear memory for each experience was assessed by measuring freezing behavior to the auditory cue and fear-potentiated startle to the light. Results showed that males trained with auditory fear conditioning showed facilitated learning to the subsequent visual fear conditioning session when the two training sessions were separated by one hour or one day. Females showed evidence of facilitation in rats given auditory conditioning when they were spaced by an hour but not when they were spaced by one day. Contextual fear conditioning did not support the facilitation of subsequent learning under any conditions. These results indicate that the mechanism by which prior fear conditioning facilitates subsequent learning differs between sexes, and they set the stage for mechanistic studies to understand the neurobiological basis of this sex difference.
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Affiliation(s)
- Kehinde E Cole
- Stony Brook University, Department of Psychology, 100 Nicolls Rd., Stony Brook, NY, 11794, United States
| | - Ryan G Parsons
- Stony Brook University, Department of Psychology, 100 Nicolls Rd., Stony Brook, NY, 11794, United States.
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35
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Décarie-Spain L, Gu C, Lauer LT, Subramanian KS, Chehimi SN, Kao AE, Deng I, Bashaw AG, Klug ME, Galbokke AH, Donohue KN, Yang M, de Lartigue G, Myers KP, Crist RC, Reiner BC, Hayes MR, Kanoski SE. Ventral hippocampus neurons encode meal-related memory. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.10.561731. [PMID: 37873229 PMCID: PMC10592790 DOI: 10.1101/2023.10.10.561731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
The ability to encode and retrieve meal-related information is critical to efficiently guide energy acquisition and consumption, yet the underlying neural processes remain elusive. Here we reveal that ventral hippocampus (HPCv) neuronal activity dynamically elevates during meal consumption and this response is highly predictive of subsequent performance in a foraging-related spatial memory task. Targeted recombination-mediated ablation of HPCv meal-responsive neurons impairs foraging-related spatial memory without influencing food motivation, anxiety-like behavior, or escape-mediated spatial memory. These HPCv meal-responsive neurons project to the lateral hypothalamic area (LHA) and single-nucleus RNA sequencing and in situ hybridization analyses indicate they are enriched in serotonin 2a receptors (5HT2aR). Either chemogenetic silencing of HPCv-to-LHA projections or intra-HPCv 5HT2aR antagonist yielded foraging-related spatial memory deficits, as well as alterations in caloric intake and the temporal sequence of spontaneous meal consumption. Collective results identify a population of HPCv neurons that dynamically respond to eating to encode meal-related memories.
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Affiliation(s)
- Léa Décarie-Spain
- Human & Evolutionary Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, California, United States
| | - Cindy Gu
- Human & Evolutionary Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, California, United States
| | - Logan Tierno Lauer
- Human & Evolutionary Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, California, United States
| | - Keshav S. Subramanian
- Neuroscience Graduate Program, University of Southern California, Los Angeles, California, United States
| | - Samar N. Chehimi
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Alicia E. Kao
- Human & Evolutionary Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, California, United States
| | - Iris Deng
- Human & Evolutionary Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, California, United States
| | - Alexander G. Bashaw
- Neuroscience Graduate Program, University of Southern California, Los Angeles, California, United States
| | - Molly E. Klug
- Human & Evolutionary Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, California, United States
| | - Ashyah Hewage Galbokke
- Human & Evolutionary Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, California, United States
| | - Kristen N. Donohue
- Human & Evolutionary Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, California, United States
| | - Mingxin Yang
- Monell Chemical Sense Center, Philadelphia, Pennsylvania, United States
| | | | - Kevin P. Myers
- Bucknell University, Lewisburg, Philadelphia, Pennsylvania, United States
| | - Richard C. Crist
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Benjamin C. Reiner
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Matthew R. Hayes
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Scott E. Kanoski
- Human & Evolutionary Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, California, United States
- Neuroscience Graduate Program, University of Southern California, Los Angeles, California, United States
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36
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Sehgal M, Ehlers VE, Moyer JR. Synaptic and intrinsic plasticity within overlapping lateral amygdala ensembles following fear conditioning. Front Cell Neurosci 2023; 17:1221176. [PMID: 37876914 PMCID: PMC10590925 DOI: 10.3389/fncel.2023.1221176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Accepted: 09/20/2023] [Indexed: 10/26/2023] Open
Abstract
Introduction New learning results in modulation of intrinsic plasticity in the underlying brain regions. Such changes in intrinsic plasticity can influence allocation and encoding of future memories such that new memories encoded during the period of enhanced excitability are linked to the original memory. The temporal window during which the two memories interact depends upon the time course of intrinsic plasticity following new learning. Methods Using the well-characterized lateral amygdala-dependent auditory fear conditioning as a behavioral paradigm, we investigated the time course of changes in intrinsic excitability within lateral amygdala neurons. Results We found transient changes in the intrinsic excitability of amygdala neurons. Neuronal excitability was increased immediately following fear conditioning and persisted for up to 4 days post-learning but was back to naïve levels 10 days following fear conditioning. We also determined the relationship between learning-induced intrinsic and synaptic plasticity. Synaptic plasticity following fear conditioning was evident for up to 24 h but not 4 days later. Importantly, we demonstrated that the enhanced neuronal intrinsic excitability was evident in many of the same neurons that had undergone synaptic plasticity immediately following fear conditioning. Interestingly, such a correlation between synaptic and intrinsic plasticity following fear conditioning was no longer present 24 h post-learning. Discussion These data demonstrate that intrinsic and synaptic changes following fear conditioning are transient and co-localized to the same neurons. Since intrinsic plasticity following fear conditioning is an important determinant for the allocation and consolidation of future amygdala-dependent memories, these findings establish a time course during which fear memories may influence each other.
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Affiliation(s)
- Megha Sehgal
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI, United States
| | - Vanessa E. Ehlers
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI, United States
| | - James R. Moyer
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, WI, United States
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, United States
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37
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Kinsky NR, Orlin DJ, Ruesch EA, Diba K, Ramirez S. Erasable Hippocampal Neural Signatures Predict Memory Discrimination. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.02.526824. [PMID: 36778486 PMCID: PMC9915633 DOI: 10.1101/2023.02.02.526824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Memories involving the hippocampus can take several days to consolidate, challenging efforts to uncover the neuronal signatures underlying this process. Using calcium imaging in freely moving mice, we tracked the hippocampal dynamics underlying memory formation across a ten-day contextual fear conditioning (CFC) task. We found that cell turnover between the conditioning chamber and a neutral arena even prior to learning predicted the accuracy of subsequent memory recall the next day. Following learning, context-specific place field remapping correlated with memory performance. To causally test whether these hippocampal dynamics support memory consolidation, we induced amnesia in a group of mice by pharmacologically blocking protein synthesis immediately following learning. We found that halting protein synthesis following learning paradoxically accelerated cell turnover and also arrested learning-related remapping, paralleling the absence of remapping observed in untreated mice that exhibited poor memory expression. Finally, coordinated neural activity that emerged following learning was dependent on intact protein synthesis and predicted memory-related freezing behavior. We conclude that context-specific place field remapping and the development of coordinated ensemble activity require protein synthesis and underlie contextual fear memory consolidation.
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Affiliation(s)
- Nathaniel R. Kinsky
- Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
- Center for Systems Neuroscience, Boston University, Boston, MA 02451, USA
- These authors contributed equally to this work
| | - Daniel J. Orlin
- Center for Systems Neuroscience, Boston University, Boston, MA 02451, USA
- Neuroscience Graduate Program, Oregon Health & Science University, Portland, OR 97239, USA
- These authors contributed equally to this work
| | - Evan A. Ruesch
- Center for Systems Neuroscience, Boston University, Boston, MA 02451, USA
| | - Kamran Diba
- Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - Steve Ramirez
- Center for Systems Neuroscience, Boston University, Boston, MA 02451, USA
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38
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Munari L, Patel V, Johnson N, Mariottini C, Prabha S, Blitzer RD, Iyengar R. Memory discrimination is promoted by the expression of the transcription repressor WT1 in the dentate gyrus. Front Behav Neurosci 2023; 17:1130840. [PMID: 37830039 PMCID: PMC10564998 DOI: 10.3389/fnbeh.2023.1130840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 08/14/2023] [Indexed: 10/14/2023] Open
Abstract
The hippocampus is critical for the precise formation of contextual memories. Overlapping inputs coming from the entorhinal cortex are processed by the trisynaptic pathway to form distinct memories. Disruption in any step of the circuit flow can lead to a lack of memory precision, and to memory interference. We have identified the transcriptional repressor Wilm's Tumor 1 (WT1) as an important regulator of synaptic plasticity involved in memory discrimination in the hippocampus. In male mice, using viral and transgenic approaches, we showed that WT1 deletion in granule cells of the dentate gyrus (DG) disrupts memory discrimination. With electrophysiological methods, we then identified changes in granule cells' excitability and DG synaptic transmission indicating that WT1 knockdown in DG granule cells disrupts the inhibitory feedforward input from mossy fibers to CA3 by decreasing mIPSCs and shifting the normal excitatory/inhibitory (E/I) balance in the DG → CA3 circuit in favor of excitation. Finally, using a chemogenetic approach, we established a causal link between granule cell hyperexcitability and memory discrimination impairments. Our results suggest that WT1 enables a circuit-level computation that drives pattern discrimination behavior.
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Affiliation(s)
| | | | | | | | | | | | - Ravi Iyengar
- Department of Pharmacological Sciences and Institute for Systems Biomedicine, Icahn School of Medicine at Mount Sinai, New York, NY, United States
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39
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Autore L, O'Leary JD, Ortega-de San Luis C, Ryan TJ. Adaptive expression of engrams by retroactive interference. Cell Rep 2023; 42:112999. [PMID: 37590145 DOI: 10.1016/j.celrep.2023.112999] [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: 03/03/2023] [Revised: 06/17/2023] [Accepted: 08/01/2023] [Indexed: 08/19/2023] Open
Abstract
Long-term memories are stored as configurations of neuronal ensembles, termed engrams. Although investigation of engram cell properties and functionality in memory recall has been extensive, less is known about how engram cells are affected by forgetting. We describe a form of interference-based forgetting using an object memory behavioral paradigm. By using activity-dependent cell labeling, we show that although retroactive interference results in decreased engram cell reactivation during recall trials, optogenetic stimulation of the labeled engram cells is sufficient to induce memory retrieval. Forgotten engrams may be reinstated via the presentation of similar or related environmental information. Furthermore, we demonstrate that engram activity is necessary for interference to occur. Taken together, these findings indicate that retroactive interference modules engram expression in a manner that is both reversible and updatable. Inference may constitute a form of adaptive forgetting where, in everyday life, new perceptual and environmental inputs modulate the natural forgetting process.
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Affiliation(s)
- Livia Autore
- School of Biochemistry and Immunology, Trinity College of Dublin, Dublin, Ireland; Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin, Ireland
| | - James D O'Leary
- School of Biochemistry and Immunology, Trinity College of Dublin, Dublin, Ireland; Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin, Ireland
| | - Clara Ortega-de San Luis
- School of Biochemistry and Immunology, Trinity College of Dublin, Dublin, Ireland; Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin, Ireland
| | - Tomás J Ryan
- School of Biochemistry and Immunology, Trinity College of Dublin, Dublin, Ireland; Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin, Ireland; Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, University of Melbourne, Melbourne, VIC, Australia; Child & Brain Development Program, Canadian Institute for Advanced Research (CIFAR), Toronto, ON, Canada.
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40
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Zaki Y, Pennington ZT, Morales-Rodriguez D, Francisco TR, LaBanca AR, Dong Z, Lamsifer S, Segura SC, Chen HT, Wick ZC, Silva AJ, van der Meer M, Shuman T, Fenton A, Rajan K, Cai DJ. Aversive experience drives offline ensemble reactivation to link memories across days. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.13.532469. [PMID: 36993254 PMCID: PMC10054942 DOI: 10.1101/2023.03.13.532469] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Memories are encoded in neural ensembles during learning and stabilized by post-learning reactivation. Integrating recent experiences into existing memories ensures that memories contain the most recently available information, but how the brain accomplishes this critical process remains unknown. Here we show that in mice, a strong aversive experience drives the offline ensemble reactivation of not only the recent aversive memory but also a neutral memory formed two days prior, linking the fear from the recent aversive memory to the previous neutral memory. We find that fear specifically links retrospectively, but not prospectively, to neutral memories across days. Consistent with prior studies, we find reactivation of the recent aversive memory ensemble during the offline period following learning. However, a strong aversive experience also increases co-reactivation of the aversive and neutral memory ensembles during the offline period. Finally, the expression of fear in the neutral context is associated with reactivation of the shared ensemble between the aversive and neutral memories. Taken together, these results demonstrate that strong aversive experience can drive retrospective memory-linking through the offline co-reactivation of recent memory ensembles with memory ensembles formed days prior, providing a neural mechanism by which memories can be integrated across days.
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Affiliation(s)
- Yosif Zaki
- Nash Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, 10029
| | - Zachary T. Pennington
- Nash Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, 10029
| | | | - Taylor R. Francisco
- Nash Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, 10029
| | - Alexa R. LaBanca
- Nash Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, 10029
| | - Zhe Dong
- Nash Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, 10029
| | - Sophia Lamsifer
- Nash Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, 10029
| | - Simón Carrillo Segura
- Graduate Program in Mechanical and Aerospace Engineering, Tandon School of Engineering, New York University, Brooklyn, NY, 11201
| | - Hung-Tu Chen
- Department of Psychological & Brain Sciences, Dartmouth College, Hanover, NH, 03755
| | - Zoé Christenson Wick
- Nash Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, 10029
| | - Alcino J. Silva
- Department of Neurobiology, Psychiatry & Biobehavioral Sciences, and Psychology, Integrative Center for Learning and Memory, Brain Research Institute, UCLA, Los Angeles, CA 90095
| | | | - Tristan Shuman
- Nash Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, 10029
| | - André Fenton
- Center for Neural Science, New York University, New York, NY, 10003
- Neuroscience Institute at the NYU Langone Medical Center, New York, NY, 10016
| | - Kanaka Rajan
- Nash Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, 10029
| | - Denise J. Cai
- Nash Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, 10029
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41
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Fang X, Alsbury-Nealy B, Wang Y, Frankland PW, Josselyn SA, Schlichting ML, Duncan KD. Time separating spatial memories does not influence their integration in humans. PLoS One 2023; 18:e0289649. [PMID: 37561677 PMCID: PMC10414573 DOI: 10.1371/journal.pone.0289649] [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: 12/24/2022] [Accepted: 07/23/2023] [Indexed: 08/12/2023] Open
Abstract
Humans can navigate through similar environments-like grocery stores-by integrating across their memories to extract commonalities or by differentiating between each to find idiosyncratic locations. Here, we investigate one factor that might impact whether two related spatial memories are integrated or differentiated: Namely, the temporal delay between experiences. Rodents have been shown to integrate memories more often when they are formed within 6 hours of each other. To test if this effect influences how humans spontaneously integrate spatial memories, we had 131 participants search for rewards in two similar virtual environments. We separated these learning experiences by either 30 minutes, 3 hours, or 27 hours. Memory integration was assessed three days later. Participants were able to integrate and simultaneously differentiate related memories across experiences. However, neither memory integration nor differentiation was modulated by temporal delay, in contrast to previous work. We further showed that both the levels of initial memory reactivation during the second experience and memory generalization to novel environments were comparable across conditions. Moreover, perseveration toward the initial reward locations during the second experience was related positively to integration and negatively to differentiation-but again, these associations did not vary by delay. Our findings identify important boundary conditions on the translation of rodent memory mechanisms to humans, motivating more research to characterize how even fundamental memory mechanisms are conserved and diverge across species.
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Affiliation(s)
- Xiaoping Fang
- Department of Psychology, University of Toronto, Toronto, Canada
- School of Psychology, Beijing Language and Culture University, Beijing, China
| | | | - Ying Wang
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Canada
- Department of Physiology, University of Toronto, Toronto, Canada
| | - Paul W. Frankland
- Department of Psychology, University of Toronto, Toronto, Canada
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Canada
- Department of Physiology, University of Toronto, Toronto, Canada
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
- Child & Brain Development Program, Canadian Institute for Advanced Research (CIFAR), Toronto, Canada
| | - Sheena A. Josselyn
- Department of Psychology, University of Toronto, Toronto, Canada
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Canada
- Department of Physiology, University of Toronto, Toronto, Canada
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
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42
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Antonoudiou P, Stone B, Colmers PLW, Evans-Strong A, Walton N, Weiss G, Maguire J. Experience-dependent information routing through the basolateral amygdala. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.02.551710. [PMID: 37577684 PMCID: PMC10418260 DOI: 10.1101/2023.08.02.551710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
The basolateral amygdala (BLA) is an emotional processing hub and is well-established to influence both positive and negative valence processing. Selective engagement of a heterogeneous cell population in the BLA is thought to contribute to this flexibility in valence processing. However, how this process is impacted by previous experiences which influence valence processing is unknown. Here we demonstrate that previous positive (EE) or negative (chronic unpredictable stress) experiences differentially influence the activity of specific populations of BLA principal neurons projecting to either the nucleus accumbens core or bed nucleus of the stria terminalis. Using chemogenetic manipulation of these projection-specific neurons we can mimic or occlude the effects of chronic unpredictable stress or enriched environment on valence processing to bidirectionally control avoidance behaviors and stress-induced helplessness. These data demonstrate that previous experiences influence the responsiveness of projection-specific BLA principal neurons, biasing information routing through the BLA, to govern valence processing.
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43
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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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44
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Guskjolen A, Cembrowski MS. Engram neurons: Encoding, consolidation, retrieval, and forgetting of memory. Mol Psychiatry 2023; 28:3207-3219. [PMID: 37369721 PMCID: PMC10618102 DOI: 10.1038/s41380-023-02137-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 06/02/2023] [Accepted: 06/13/2023] [Indexed: 06/29/2023]
Abstract
Tremendous strides have been made in our understanding of the neurobiological substrates of memory - the so-called memory "engram". Here, we integrate recent progress in the engram field to illustrate how engram neurons transform across the "lifespan" of a memory - from initial memory encoding, to consolidation and retrieval, and ultimately to forgetting. To do so, we first describe how cell-intrinsic properties shape the initial emergence of the engram at memory encoding. Second, we highlight how these encoding neurons preferentially participate in synaptic- and systems-level consolidation of memory. Third, we describe how these changes during encoding and consolidation guide neural reactivation during retrieval, and facilitate memory recall. Fourth, we describe neurobiological mechanisms of forgetting, and how these mechanisms can counteract engram properties established during memory encoding, consolidation, and retrieval. Motivated by recent experimental results across these four sections, we conclude by proposing some conceptual extensions to the traditional view of the engram, including broadening the view of cell-type participation within engrams and across memory stages. In collection, our review synthesizes general principles of the engram across memory stages, and describes future avenues to further understand the dynamic engram.
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Affiliation(s)
- Axel Guskjolen
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada.
| | - Mark S Cembrowski
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada.
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada.
- School of Biomedical Engineering, University of British Columbia, Vancouver, BC, Canada.
- Department of Mathematics, University of British Columbia, Vancouver, BC, Canada.
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45
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Sierra RO, Pedraza LK, Barcsai L, Pejin A, Li Q, Kozák G, Takeuchi Y, Nagy AJ, Lőrincz ML, Devinsky O, Buzsáki G, Berényi A. Closed-loop brain stimulation augments fear extinction in male rats. Nat Commun 2023; 14:3972. [PMID: 37407557 DOI: 10.1038/s41467-023-39546-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Accepted: 06/16/2023] [Indexed: 07/07/2023] Open
Abstract
Dysregulated fear reactions can result from maladaptive processing of trauma-related memories. In post-traumatic stress disorder (PTSD) and other psychiatric disorders, dysfunctional extinction learning prevents discretization of trauma-related memory engrams and generalizes fear responses. Although PTSD may be viewed as a memory-based disorder, no approved treatments target pathological fear memory processing. Hippocampal sharp wave-ripples (SWRs) and concurrent neocortical oscillations are scaffolds to consolidate contextual memory, but their role during fear processing remains poorly understood. Here, we show that closed-loop, SWR triggered neuromodulation of the medial forebrain bundle (MFB) can enhance fear extinction consolidation in male rats. The modified fear memories became resistant to induced recall (i.e., 'renewal' and 'reinstatement') and did not reemerge spontaneously. These effects were mediated by D2 receptor signaling-induced synaptic remodeling in the basolateral amygdala. Our results demonstrate that SWR-triggered closed-loop stimulation of the MFB reward system enhances extinction of fearful memories and reducing fear expression across different contexts and preventing excessive and persistent fear responses. These findings highlight the potential of neuromodulation to augment extinction learning and provide a new avenue to develop treatments for anxiety disorders.
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Affiliation(s)
- Rodrigo Ordoñez Sierra
- MTA-SZTE 'Momentum' Oscillatory Neuronal Networks Research Group, Department of Physiology, University of Szeged, Szeged, 6720, Hungary
| | - Lizeth Katherine Pedraza
- MTA-SZTE 'Momentum' Oscillatory Neuronal Networks Research Group, Department of Physiology, University of Szeged, Szeged, 6720, Hungary
| | - Lívia Barcsai
- MTA-SZTE 'Momentum' Oscillatory Neuronal Networks Research Group, Department of Physiology, University of Szeged, Szeged, 6720, Hungary
- HCEMM-SZTE Magnetotherapeutics Research Group, University of Szeged, Szeged, 6720, Hungary
- Neunos Inc, Boston, MA, 02108, USA
| | - Andrea Pejin
- MTA-SZTE 'Momentum' Oscillatory Neuronal Networks Research Group, Department of Physiology, University of Szeged, Szeged, 6720, Hungary
- HCEMM-SZTE Magnetotherapeutics Research Group, University of Szeged, Szeged, 6720, Hungary
- Neunos Inc, Boston, MA, 02108, USA
| | - Qun Li
- MTA-SZTE 'Momentum' Oscillatory Neuronal Networks Research Group, Department of Physiology, University of Szeged, Szeged, 6720, Hungary
| | - Gábor Kozák
- MTA-SZTE 'Momentum' Oscillatory Neuronal Networks Research Group, Department of Physiology, University of Szeged, Szeged, 6720, Hungary
| | - Yuichi Takeuchi
- MTA-SZTE 'Momentum' Oscillatory Neuronal Networks Research Group, Department of Physiology, University of Szeged, Szeged, 6720, Hungary
- Department of Biopharmaceutical Sciences and Pharmacy, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
| | - Anett J Nagy
- MTA-SZTE 'Momentum' Oscillatory Neuronal Networks Research Group, Department of Physiology, University of Szeged, Szeged, 6720, Hungary
- HCEMM-SZTE Magnetotherapeutics Research Group, University of Szeged, Szeged, 6720, Hungary
- Neunos Inc, Boston, MA, 02108, USA
| | - Magor L Lőrincz
- MTA-SZTE 'Momentum' Oscillatory Neuronal Networks Research Group, Department of Physiology, University of Szeged, Szeged, 6720, Hungary
- Department of Physiology, Anatomy and Neuroscience, Faculty of Sciences University of Szeged, Szeged, 6726, Hungary
- Neuroscience Division, Cardiff University, Museum Avenue, Cardiff, CF10 3AX, UK
| | - Orrin Devinsky
- Department of Neurology, NYU Langone Comprehensive Epilepsy Center, NYU Grossman School of Medicine, New York, NY, 10016, USA
| | - György Buzsáki
- Neuroscience Institute, New York University, New York, NY, 10016, USA
- Center for Neural Science, New York University, New York, NY, 10016, USA
| | - Antal Berényi
- MTA-SZTE 'Momentum' Oscillatory Neuronal Networks Research Group, Department of Physiology, University of Szeged, Szeged, 6720, Hungary.
- HCEMM-SZTE Magnetotherapeutics Research Group, University of Szeged, Szeged, 6720, Hungary.
- Neunos Inc, Boston, MA, 02108, USA.
- Neuroscience Institute, New York University, New York, NY, 10016, USA.
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Suthard RL, Senne RA, Buzharsky MD, Pyo AY, Dorst KE, Diep AH, Cole RH, Ramirez S. Basolateral Amygdala Astrocytes Are Engaged by the Acquisition and Expression of a Contextual Fear Memory. J Neurosci 2023; 43:4997-5013. [PMID: 37268419 PMCID: PMC10324998 DOI: 10.1523/jneurosci.1775-22.2023] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 05/11/2023] [Accepted: 05/18/2023] [Indexed: 06/04/2023] Open
Abstract
Astrocytes are key cellular regulators within the brain. The basolateral amygdala (BLA) is implicated in fear memory processing, yet most research has entirely focused on neuronal mechanisms, despite a significant body of work implicating astrocytes in learning and memory. In the present study, we used in vivo fiber photometry in C57BL/6J male mice to record from amygdalar astrocytes across fear learning, recall, and three separate periods of extinction. We found that BLA astrocytes robustly responded to foot shock during acquisition, their activity remained remarkably elevated across days in comparison to unshocked control animals, and their increased activity persisted throughout extinction. Further, we found that astrocytes responded to the initiation and termination of freezing bouts during contextual fear conditioning and recall, and this behavior-locked pattern of activity did not persist throughout the extinction sessions. Importantly, astrocytes do not display these changes while exploring a novel context, suggesting that these observations are specific to the original fear-associated environment. Chemogenetic inhibition of fear ensembles in the BLA did not affect freezing behavior or astrocytic calcium dynamics. Overall, our work presents a real-time role for amygdalar astrocytes in fear processing and provides new insight into the emerging role of these cells in cognition and behavior.SIGNIFICANCE STATEMENT We show that basolateral amygdala astrocytes are robustly responsive to negative experiences, like shock, and display changed calcium activity patterns through fear learning and memory. Additionally, astrocytic calcium responses become time locked to the initiation and termination of freezing behavior during fear learning and recall. We find that astrocytes display calcium dynamics unique to a fear-conditioned context, and chemogenetic inhibition of BLA fear ensembles does not have an impact on freezing behavior or calcium dynamics. These findings show that astrocytes play a key real-time role in fear learning and memory.
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Affiliation(s)
- Rebecca L Suthard
- Graduate Program for Neuroscience, Boston University, Boston, Massachusetts 02215
- Department of Psychological and Brain Sciences, Center for Systems Neuroscience, Neurophotonics Center, and Photonics Center, Boston University, Boston, Massachusetts 02215
| | - Ryan A Senne
- Graduate Program for Neuroscience, Boston University, Boston, Massachusetts 02215
- Department of Psychological and Brain Sciences, Center for Systems Neuroscience, Neurophotonics Center, and Photonics Center, Boston University, Boston, Massachusetts 02215
| | - Michelle D Buzharsky
- Undergraduate Program in Neuroscience, Boston University, Boston, Massachusetts 02215
| | - Angela Y Pyo
- Department of Psychological and Brain Sciences, Center for Systems Neuroscience, Neurophotonics Center, and Photonics Center, Boston University, Boston, Massachusetts 02215
| | - Kaitlyn E Dorst
- Graduate Program for Neuroscience, Boston University, Boston, Massachusetts 02215
- Department of Psychological and Brain Sciences, Center for Systems Neuroscience, Neurophotonics Center, and Photonics Center, Boston University, Boston, Massachusetts 02215
| | - Anh H Diep
- Undergraduate Program in Neuroscience, Boston University, Boston, Massachusetts 02215
| | - Rebecca H Cole
- Undergraduate Program in Neuroscience, Boston University, Boston, Massachusetts 02215
| | - Steve Ramirez
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts 02215
- Department of Psychological and Brain Sciences, Center for Systems Neuroscience, Neurophotonics Center, and Photonics Center, Boston University, Boston, Massachusetts 02215
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47
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Cole KE, Parsons RG. Sex difference in the facilitation of fear learning by prior fear conditioning. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.29.547102. [PMID: 37425868 PMCID: PMC10327064 DOI: 10.1101/2023.06.29.547102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
There is now ample evidence that the strength and underlying mechanisms of memory formation can be drastically altered by prior experience. However, the prior work using rodent models on this topic has used only males as subjects, and as a result, we do know whether or not the effects of prior experience on subsequent learning are similar in both sexes. As a first step towards addressing this shortcoming rats of both sexes were given auditory fear conditioning, or fear conditioning with unsignaled shocks, followed an hour or a day later by a single pairing of light and shock. Fear memory for each experience was assessed by measuring freezing behavior to the auditory cue and fear-potentiated startle to the light. Results showed that males trained with auditory fear conditioning showed facilitated learning to the subsequent visual fear conditioning session when the two training sessions were separated by one hour or one day. Females showed evidence of facilitation in rats given auditory conditioning when they were spaced by an hour, but not when they were spaced by one day. Contextual fear conditioning did not support the facilitation of subsequent learning under any conditions. These results indicate that the mechanism by which prior fear conditioning facilitates subsequent learning differs between sexes, and they set the stage for mechanistic studies to understand the neurobiological basis of this sex difference.
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Affiliation(s)
- Kehinde E Cole
- Stony Brook University, Department of Psychology, 100 Nicolls Rd., Stony Brook, NY, 11794
| | - Ryan G Parsons
- Stony Brook University, Department of Psychology, 100 Nicolls Rd., Stony Brook, NY, 11794
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48
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Miller AMP, Jacob AD, Ramsaran AI, De Snoo ML, Josselyn SA, Frankland PW. Emergence of a predictive model in the hippocampus. Neuron 2023; 111:1952-1965.e5. [PMID: 37015224 PMCID: PMC10293047 DOI: 10.1016/j.neuron.2023.03.011] [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: 09/08/2022] [Revised: 01/23/2023] [Accepted: 03/08/2023] [Indexed: 04/05/2023]
Abstract
The brain organizes experiences into memories that guide future behavior. Hippocampal CA1 population activity is hypothesized to reflect predictive models that contain information about future events, but little is known about how they develop. We trained mice on a series of problems with or without a common statistical structure to observe how memories are formed and updated. Mice that learned structured problems integrated their experiences into a predictive model that contained the solutions to upcoming novel problems. Retrieving the model during learning improved discrimination accuracy and facilitated learning. Using calcium imaging to track CA1 activity during learning, we found that hippocampal ensemble activity became more stable as mice formed a predictive model. The hippocampal ensemble was reactivated during training and incorporated new activity patterns from each training problem. These results show how hippocampal activity supports building predictive models by organizing new information with respect to existing memories.
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Affiliation(s)
- Adam M P Miller
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, ON, Canada
| | - Alex D Jacob
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, ON, Canada; Department of Psychology, University of Toronto, Toronto, ON, Canada
| | - Adam I Ramsaran
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, ON, Canada; Department of Psychology, University of Toronto, Toronto, ON, Canada
| | - Mitchell L De Snoo
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, ON, Canada; Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada
| | - Sheena A Josselyn
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, ON, Canada; Department of Psychology, University of Toronto, Toronto, ON, Canada; Department of Physiology, University of Toronto, Toronto, ON, Canada; Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada; Brain, Mind, & Consciousness Program, Canadian Institute for Advanced Research, Toronto, ON, Canada
| | - Paul W Frankland
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, ON, Canada; Department of Psychology, University of Toronto, Toronto, ON, Canada; Department of Physiology, University of Toronto, Toronto, ON, Canada; Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada; Child & Brain Development Program, Canadian Institute for Advanced Research, Toronto, ON, Canada.
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49
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Teng SW, Wang XR, Du BW, Chen XL, Fu GZ, Liu YF, Xu SQ, Shuai JC, Chen ZY. Altered fear engram encoding underlying conditioned versus unconditioned stimulus-initiated memory updating. SCIENCE ADVANCES 2023; 9:eadf0284. [PMID: 37285430 DOI: 10.1126/sciadv.adf0284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Accepted: 05/03/2023] [Indexed: 06/09/2023]
Abstract
It is known that post-retrieval extinction but not extinction alone could erase fear memory. However, whether the coding pattern of original fear engrams is remodeled or inhibited remains largely unclear. We found increased reactivation of engram cells in the prelimbic cortex and basolateral amygdala during memory updating. Moreover, conditioned stimulus- and unconditioned stimulus-initiated memory updating depends on the engram cell reactivation in the prelimbic cortex and basolateral amygdala, respectively. Last, we found that memory updating causes increased overlapping between fear and extinction cells, and the original fear engram encoding was altered during memory updating. Our data provide the first evidence to show the overlapping ensembles between fear and extinction cells and the functional reorganization of original engrams underlying conditioned stimulus- and unconditioned stimulus-initiated memory updating.
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Affiliation(s)
- Shuai-Wen Teng
- Department of Anatomy and Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, School of Basic Medical Sciences and Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250012, P.R. China
| | - Xin-Rong Wang
- Department of Anatomy and Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, School of Basic Medical Sciences and Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250012, P.R. China
| | - Bo-Wen Du
- Department of Anatomy and Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, School of Basic Medical Sciences and Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250012, P.R. China
| | - Xiao-Lin Chen
- Department of Anatomy and Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, School of Basic Medical Sciences and Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250012, P.R. China
| | - Guan-Zhou Fu
- Department of Anatomy and Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, School of Basic Medical Sciences and Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250012, P.R. China
| | - Yun-Fei Liu
- Department of Anatomy and Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, School of Basic Medical Sciences and Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250012, P.R. China
| | - Shu-Qi Xu
- Department of Anatomy and Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, School of Basic Medical Sciences and Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250012, P.R. China
| | - Jia-Chen Shuai
- Department of Anatomy and Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, School of Basic Medical Sciences and Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250012, P.R. China
| | - Zhe-Yu Chen
- Department of Anatomy and Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, School of Basic Medical Sciences and Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250012, P.R. China
- Institute of Brain Science, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai 201203, P.R. China
- Institution of Traditional Chinese Medicine Innovation Research, Shandong University of Traditional Chinese Medicine, Jinan 250355, P.R. China
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Geva N, Deitch D, Rubin A, Ziv Y. Time and experience differentially affect distinct aspects of hippocampal representational drift. Neuron 2023:S0896-6273(23)00378-1. [PMID: 37315556 DOI: 10.1016/j.neuron.2023.05.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 02/22/2023] [Accepted: 05/08/2023] [Indexed: 06/16/2023]
Abstract
Hippocampal activity is critical for spatial memory. Within a fixed, familiar environment, hippocampal codes gradually change over timescales of days to weeks-a phenomenon known as representational drift. The passage of time and the amount of experience are two factors that profoundly affect memory. However, thus far, it has remained unclear to what extent these factors drive hippocampal representational drift. Here, we longitudinally recorded large populations of hippocampal neurons in mice while they repeatedly explored two different familiar environments that they visited at different time intervals over weeks. We found that time and experience differentially affected distinct aspects of representational drift: the passage of time drove changes in neuronal activity rates, whereas experience drove changes in the cells' spatial tuning. Changes in spatial tuning were context specific and largely independent of changes in activity rates. Thus, our results suggest that representational drift is a multi-faceted process governed by distinct neuronal mechanisms.
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Affiliation(s)
- Nitzan Geva
- Department of Brain Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Daniel Deitch
- Department of Brain Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Alon Rubin
- Department of Brain Sciences, Weizmann Institute of Science, Rehovot, Israel.
| | - Yaniv Ziv
- Department of Brain Sciences, Weizmann Institute of Science, Rehovot, Israel.
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