1
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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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2
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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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3
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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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4
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Lopez-Ortega E, Choi JY, Hong I, Roth RH, Cudmore RH, Huganir RL. Stimulus-dependent synaptic plasticity underlies neuronal circuitry refinement in the mouse primary visual cortex. Cell Rep 2024; 43:113966. [PMID: 38507408 PMCID: PMC11210464 DOI: 10.1016/j.celrep.2024.113966] [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: 12/26/2023] [Accepted: 02/28/2024] [Indexed: 03/22/2024] Open
Abstract
Perceptual learning improves our ability to interpret sensory stimuli present in our environment through experience. Despite its importance, the underlying mechanisms that enable perceptual learning in our sensory cortices are still not fully understood. In this study, we used in vivo two-photon imaging to investigate the functional and structural changes induced by visual stimulation in the mouse primary visual cortex (V1). Our results demonstrate that repeated stimulation leads to a refinement of V1 circuitry by decreasing the number of responsive neurons while potentiating their response. At the synaptic level, we observe a reduction in the number of dendritic spines and an overall increase in spine AMPA receptor levels in the same subset of neurons. In addition, visual stimulation induces synaptic potentiation in neighboring spines within individual dendrites. These findings provide insights into the mechanisms of synaptic plasticity underlying information processing in the neocortex.
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Affiliation(s)
- Elena Lopez-Ortega
- Department of Neuroscience, Kavli Neuroscience Discovery Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Jung Yoon Choi
- Department of Neuroscience, Kavli Neuroscience Discovery Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Ingie Hong
- Department of Neuroscience, Kavli Neuroscience Discovery Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Richard H Roth
- Department of Neuroscience, Kavli Neuroscience Discovery Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Robert H Cudmore
- Department of Neuroscience, Kavli Neuroscience Discovery Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Richard L Huganir
- Department of Neuroscience, Kavli Neuroscience Discovery Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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5
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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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6
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Refaeli R, Kreisel T, Yaish TR, Groysman M, Goshen I. Astrocytes control recent and remote memory strength by affecting the recruitment of the CA1→ACC projection to engrams. Cell Rep 2024; 43:113943. [PMID: 38483907 PMCID: PMC10995765 DOI: 10.1016/j.celrep.2024.113943] [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: 10/08/2023] [Revised: 01/14/2024] [Accepted: 02/23/2024] [Indexed: 04/02/2024] Open
Abstract
The maturation of engrams from recent to remote time points involves the recruitment of CA1 neurons projecting to the anterior cingulate cortex (CA1→ACC). Modifications of G-protein-coupled receptor pathways in CA1 astrocytes affect recent and remote recall in seemingly contradictory ways. To address this inconsistency, we manipulated these pathways in astrocytes during memory acquisition and tagged c-Fos-positive engram cells and CA1→ACC cells during recent and remote recall. The behavioral results were coupled with changes in the recruitment of CA1→ACC projection cells to the engram: Gq pathway activation in astrocytes caused enhancement of recent recall alone and was accompanied by earlier recruitment of CA1→ACC projecting cells to the engram. In contrast, Gi pathway activation in astrocytes resulted in the impairment of only remote recall, and CA1→ACC projecting cells were not recruited during remote memory. Finally, we provide a simple working model, hypothesizing that Gq and Gi pathway activation affect memory differently, by modulating the same mechanism: CA1→ACC projection.
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Affiliation(s)
- Ron Refaeli
- Edmond and Lily Safra Center for Brain Sciences (ELSC), The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Tirzah Kreisel
- Edmond and Lily Safra Center for Brain Sciences (ELSC), The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | | | - Maya Groysman
- ELSC Vector Core Facility, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Inbal Goshen
- Edmond and Lily Safra Center for Brain Sciences (ELSC), The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
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7
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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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8
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Liu M, Fan Y, Ni N, Yu T, Mao Z, Huang H, Zhang J, Tang Y, He H, Meng F, You Y, Zhou Q. TERT mediates the U-shape of glucocorticoids effects in modulation of hippocampal neural stem cells and associated brain function. CNS Neurosci Ther 2024; 30:e14577. [PMID: 38421107 PMCID: PMC10850922 DOI: 10.1111/cns.14577] [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: 07/06/2023] [Revised: 10/17/2023] [Accepted: 12/07/2023] [Indexed: 03/02/2024] Open
Abstract
BACKGROUND Glucocorticoids (GCs) are steroidal hormones produced by the adrenal cortex. A physiological-level GCs have a crucial function in maintaining many cognitive processes, like cognition, memory, and mood, however, both insufficient and excessive GCs impair these functions. Although this phenomenon could be explained by the U-shape of GC effects, the underlying mechanisms are still not clear. Therefore, understanding the underlying mechanisms of GCs may provide insight into the treatments for cognitive and mood-related disorders. METHODS Consecutive administration of corticosterone (CORT, 10 mg/kg, i.g.) proceeded for 28 days to mimic excessive GCs condition. Adrenalectomy (ADX) surgery was performed to ablate endogenous GCs in mice. Microinjection of 1 μL of Ad-mTERT-GFP virus into mouse hippocampus dentate gyrus (DG) and behavioral alterations in mice were observed 4 weeks later. RESULTS Different concentrations of GCs were shown to affect the cell growth and development of neural stem cells (NSCs) in a U-shaped manner. The physiological level of GCs (0.01 μM) promoted NSC proliferation in vitro, while the stress level of GCs (10 μM) inhibited it. The glucocorticoid synthesis blocker metyrapone (100 mg/kg, i.p.) and ADX surgery both decreased the quantity and morphological development of doublecortin (DCX)-positive immature cells in the DG. The physiological level of GCs activated mineralocorticoid receptor and then promoted the production of telomerase reverse transcriptase (TERT); in contrast, the stress level of GCs activated glucocorticoid receptor and then reduced the expression of TERT. Overexpression of TERT by AD-mTERT-GFP reversed both chronic stresses- and ADX-induced deficiency of TERT and the proliferation and development of NSCs, chronic stresses-associated depressive symptoms, and ADX-associated learning and memory impairment. CONCLUSION The bidirectional regulation of TERT by different GCs concentrations is a key mechanism mediating the U-shape of GC effects in modulation of hippocampal NSCs and associated brain function. Replenishment of TERT could be a common treatment strategy for GC dysfunction-associated diseases.
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Affiliation(s)
- Meng‐Ying Liu
- Department of Pharmacy, Nanjing Drum Tower HospitalAffiliated Hospital of Medical School, Nanjing UniversityNanjingChina
- State Key Laboratory of Reproductive Medicine, Department of Clinical Pharmacology, School of PharmacyNanjing Medical UniversityNanjingChina
| | - Yixin Fan
- State Key Laboratory of Reproductive Medicine, Department of Clinical Pharmacology, School of PharmacyNanjing Medical UniversityNanjingChina
- Department of Pharmacy, Sir Run Run HospitalNanjing Medical UniversityNanjingChina
| | - Ningjie Ni
- State Key Laboratory of Reproductive Medicine, Department of Clinical Pharmacology, School of PharmacyNanjing Medical UniversityNanjingChina
- Department of NeurosurgeryThe First Affiliated Hospital of Nanjing Medical UniversityNanjingChina
| | - Tao Yu
- School of PharmacyNanjing Medical UniversityNanjingChina
| | - Zhiyuan Mao
- Key Laboratory for Aging & Disease, The State Key Laboratory of Reproductive Medicine, Department of Human Anatomy, Research Centre for Bone and Stem CellsNanjing Medical UniversityNanjingChina
| | - Hanyu Huang
- State Key Laboratory of Reproductive Medicine, Department of Clinical Pharmacology, School of PharmacyNanjing Medical UniversityNanjingChina
- Department of NeurosurgeryThe First Affiliated Hospital of Nanjing Medical UniversityNanjingChina
| | - Jing Zhang
- Department of Clinical Pharmacology, School of PharmacyNanjing Medical UniversityNanjingChina
| | - Yulin Tang
- Department of Pharmacy, Sir Run Run HospitalNanjing Medical UniversityNanjingChina
| | - Hongliang He
- Department of Pharmacy, Sir Run Run HospitalNanjing Medical UniversityNanjingChina
| | - Fan Meng
- Department of Clinical Pharmacology, School of PharmacyNanjing Medical UniversityNanjingChina
| | - Yongping You
- Department of NeurosurgeryThe First Affiliated Hospital of Nanjing Medical UniversityNanjingChina
| | - Qi‐Gang Zhou
- State Key Laboratory of Reproductive Medicine, Department of Clinical Pharmacology, School of PharmacyNanjing Medical UniversityNanjingChina
- Department of Pharmacy, Sir Run Run HospitalNanjing Medical UniversityNanjingChina
- Department of Clinical Pharmacology, School of PharmacyNanjing Medical UniversityNanjingChina
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9
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Zimmerman CA, Pan-Vazquez A, Wu B, Keppler EF, Guthman EM, Fetcho RN, Bolkan SS, McMannon B, Lee J, Hoag AT, Lynch LA, Janarthanan SR, López Luna JF, Bondy AG, Falkner AL, Wang SSH, Witten IB. A neural mechanism for learning from delayed postingestive feedback. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.10.06.561214. [PMID: 37873112 PMCID: PMC10592633 DOI: 10.1101/2023.10.06.561214] [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
Animals learn the value of foods based on their postingestive effects and thereby develop aversions to foods that are toxic1-6 and preferences to those that are nutritious7-14. However, it remains unclear how the brain is able to assign credit to flavors experienced during a meal with postingestive feedback signals that can arise after a substantial delay. Here, we reveal an unexpected role for postingestive reactivation of neural flavor representations in this temporal credit assignment process. To begin, we leverage the fact that mice learn to associate novel15-18, but not familiar, flavors with delayed gastric malaise signals to investigate how the brain represents flavors that support aversive postingestive learning. Surveying cellular resolution brainwide activation patterns reveals that a network of amygdala regions is unique in being preferentially activated by novel flavors across every stage of the learning process: the initial meal, delayed malaise, and memory retrieval. By combining high-density recordings in the amygdala with optogenetic stimulation of genetically defined hindbrain malaise cells, we find that postingestive malaise signals potently and specifically reactivate amygdalar novel flavor representations from a recent meal. The degree of malaise-driven reactivation of individual neurons predicts strengthening of flavor responses upon memory retrieval, leading to stabilization of the population-level representation of the recently consumed flavor. In contrast, meals without postingestive consequences degrade neural flavor representations as flavors become familiar and safe. Thus, our findings demonstrate that interoceptive reactivation of amygdalar flavor representations provides a neural mechanism to resolve the temporal credit assignment problem inherent to postingestive learning.
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Affiliation(s)
| | | | - Bichan Wu
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ, USA
| | - Emma F Keppler
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ, USA
| | - Eartha Mae Guthman
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ, USA
| | - Robert N Fetcho
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ, USA
| | - Scott S Bolkan
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ, USA
| | - Brenna McMannon
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ, USA
| | - Junuk Lee
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ, USA
| | - Austin T Hoag
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ, USA
| | - Laura A Lynch
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ, USA
| | | | - Juan F López Luna
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ, USA
| | - Adrian G Bondy
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ, USA
| | - Annegret L Falkner
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ, USA
| | - Samuel S-H Wang
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ, USA
| | - Ilana B Witten
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ, USA
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10
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Xiao H, Xu Y, Cui S, Wang JH. Neuroligin-3-Mediated Synapse Formation Strengthens Interactions between Hippocampus and Barrel Cortex in Associative Memory. Int J Mol Sci 2024; 25:711. [PMID: 38255783 PMCID: PMC10815421 DOI: 10.3390/ijms25020711] [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: 11/28/2023] [Revised: 12/16/2023] [Accepted: 12/17/2023] [Indexed: 01/24/2024] Open
Abstract
Memory traces are believed to be broadly allocated in cerebral cortices and the hippocampus. Mutual synapse innervations among these brain areas are presumably formed in associative memory. In the present study, we have used neuronal tracing by pAAV-carried fluorescent proteins and neuroligin-3 mRNA knockdown by shRNAs to examine the role of neuroligin-3-mediated synapse formation in the interconnection between primary associative memory cells in the sensory cortices and secondary associative memory cells in the hippocampus during the acquisition and memory of associated signals. Our studies show that mutual synapse innervations between the barrel cortex and the hippocampal CA3 region emerge and are upregulated after the memories of associated whisker and odor signals come into view. These synapse interconnections are downregulated by a knockdown of neuroligin-3-mediated synapse linkages. New synapse interconnections and the strengthening of these interconnections appear to endorse the belief in an interaction between the hippocampus and sensory cortices for memory consolidation.
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Affiliation(s)
- Huajuan Xiao
- Sino-Danish College, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yang Xu
- College of Life Science, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shan Cui
- Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Jin-Hui Wang
- College of Life Science, University of Chinese Academy of Sciences, Beijing 100049, China
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11
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Yelhekar TD, Meng M, Doupe J, Lin Y. All IEGs Are Not Created Equal-Molecular Sorting Within the Memory Engram. ADVANCES IN NEUROBIOLOGY 2024; 38:81-109. [PMID: 39008012 DOI: 10.1007/978-3-031-62983-9_6] [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
When neurons are recruited to form the memory engram, they are driven to activate the expression of a series of immediate-early genes (IEGs). While these IEGs have been used relatively indiscriminately to identify the so-called engram neurons, recent research has demonstrated that different IEG ensembles can be physically and functionally distinct within the memory engram. This inherent heterogeneity of the memory engram is driven by the diversity in the functions and distributions of different IEGs. This process, which we call molecular sorting, is analogous to sorting the entire population of engram neurons into different sub-engrams molecularly defined by different IEGs. In this chapter, we will describe the molecular sorting process by systematically reviewing published work on engram ensemble cells defined by the following four major IEGs: Fos, Npas4, Arc, and Egr1. By comparing and contrasting these likely different components of the memory engram, we hope to gain a better understanding of the logic and significance behind the molecular sorting process for memory functions.
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Affiliation(s)
- Tushar D Yelhekar
- Department of Psychiatry, O'Donnell Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Meizhen Meng
- Department of Psychiatry, O'Donnell Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Neuroscience Graduate Program, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Joslyn Doupe
- Neuroscience Graduate Program, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Yingxi Lin
- Department of Psychiatry, O'Donnell Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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12
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Zhang Y, Roy DS. Memory Storage in Distributed Engram Cell Ensembles. ADVANCES IN NEUROBIOLOGY 2024; 38:29-43. [PMID: 39008009 DOI: 10.1007/978-3-031-62983-9_3] [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
One of the most fascinating aspects of the brain is its ability to acquire new information from experience and retain it over time as memory. The search for physical correlates of memory, the memory engram, has been a longstanding priority in modern neurobiology. Advanced genetic approaches have led to the localization of engram cells in a few brain regions, including the hippocampus and cortex. Additionally, engram cells exhibit learning-induced, persistent modifications and have at least two states, active and silent. However, it has been hypothesized that engrams for a specific memory are distributed among multiple brain regions that are functionally connected, referred to as a unified engram complex. Recent tissue-clearing techniques have permitted high-throughput analyses of intact brain samples, which have been used to obtain a map of the engram complex for a contextual fear memory. Careful examination of these engram complex maps has revealed a potentially underappreciated contribution of subcortical regions, specifically thalamic nuclei, to memory function. These more holistic studies support the unified engram complex hypothesis for memory storage and have important implications for understanding dysfunctional engrams in the context of human disease.
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Affiliation(s)
- Ying Zhang
- Center for Life Sciences & IDG/McGovern Institute for Brain Research, School of Life Sciences, Tsinghua University, Haidian District, Beijing, China
| | - Dheeraj S Roy
- Department of Physiology and Biophysics, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY, USA.
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13
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Kitamura T, Ramesh K, Terranova JI. Understanding Others' Distress Through Past Experiences: The Role of Memory Engram Cells in Observational Fear. ADVANCES IN NEUROBIOLOGY 2024; 38:215-234. [PMID: 39008018 DOI: 10.1007/978-3-031-62983-9_12] [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
For individuals to survive and function in society, it is essential that they recognize, interact with, and learn from other conspecifics. Observational fear (OF) is the well-conserved empathic ability of individuals to understand the other's aversive situation. While it is widely known that factors such as prior similar aversive experience and social familiarity with the demonstrator facilitate OF, the neural circuit mechanisms that explicitly regulate experience-dependent OF (Exp OF) were unclear. In this review, we examine the neural circuit mechanisms that regulate OF, with an emphasis on rodent models, and then discuss emerging evidence for the role of fear memory engram cells in the regulation of Exp OF. First, we examine the neural circuit mechanisms that underlie Naive OF, which is when an observer lacks prior experiences relevant to OF. In particular, the anterior cingulate cortex to basolateral amygdala (BLA) neural circuit is essential for Naive OF. Next, we discuss a recent study that developed a behavioral paradigm in mice to examine the neural circuit mechanisms that underlie Exp OF. This study found that fear memory engram cells in the BLA of observers, which form during a prior similar aversive experience with shock, are reactivated by ventral hippocampal neurons in response to shock delivery to the familiar demonstrator to elicit Exp OF. Finally, we discuss the implications of fear memory engram cells in Exp OF and directions of future research that are of both translational and basic interest.
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Affiliation(s)
- Takashi Kitamura
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, USA.
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX, USA.
- Peter O'Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX, USA.
| | - Kritika Ramesh
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, USA
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14
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Xu Y, Cui TL, Li JY, Chen B, Wang JH. Associative memory neurons of encoding multi-modal signals are recruited by neuroligin-3-mediated new synapse formation. eLife 2023; 12:RP87969. [PMID: 38047770 PMCID: PMC10695560 DOI: 10.7554/elife.87969] [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: 12/05/2023] Open
Abstract
The joint storage and reciprocal retrieval of learnt associated signals are presumably encoded by associative memory cells. In the accumulation and enrichment of memory contents in lifespan, a signal often becomes a core signal associatively shared for other signals. One specific group of associative memory neurons that encode this core signal likely interconnects multiple groups of associative memory neurons that encode these other signals for their joint storage and reciprocal retrieval. We have examined this hypothesis in a mouse model of associative learning by pairing the whisker tactile signal sequentially with the olfactory signal, the gustatory signal, and the tail-heating signal. Mice experienced this associative learning show the whisker fluctuation induced by olfactory, gustatory, and tail-heating signals, or the other way around, that is, memories to multi-modal associated signals featured by their reciprocal retrievals. Barrel cortical neurons in these mice become able to encode olfactory, gustatory, and tail-heating signals alongside the whisker signal. Barrel cortical neurons interconnect piriform, S1-Tr, and gustatory cortical neurons. With the barrel cortex as the hub, the indirect activation occurs among piriform, gustatory, and S1-Tr cortices for the second-order associative memory. These associative memory neurons recruited to encode multi-modal signals in the barrel cortex for associative memory are downregulated by neuroligin-3 knockdown. Thus, associative memory neurons can be recruited as the core cellular substrate to memorize multiple associated signals for the first-order and the second-order of associative memories by neuroligin-3-mediated synapse formation, which constitutes neuronal substrates of cognitive activities in the field of memoriology.
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Affiliation(s)
- Yang Xu
- College of Life Science, University of Chinese Academy of SciencesBeijingChina
| | - Tian-liang Cui
- College of Life Science, University of Chinese Academy of SciencesBeijingChina
| | - Jia-yi Li
- College of Life Science, University of Chinese Academy of SciencesBeijingChina
| | - Bingchen Chen
- College of Life Science, University of Chinese Academy of SciencesBeijingChina
| | - Jin-Hui Wang
- College of Life Science, University of Chinese Academy of SciencesBeijingChina
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15
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Bertocchi I, Rocha-Almeida F, Romero-Barragán MT, Cambiaghi M, Carretero-Guillén A, Botta P, Dogbevia GK, Treviño M, Mele P, Oberto A, Larkum ME, Gruart A, Sprengel R, Delgado-García JM, Hasan MT. Pre- and postsynaptic N-methyl-D-aspartate receptors are required for sequential printing of fear memory engrams. iScience 2023; 26:108050. [PMID: 37876798 PMCID: PMC10590821 DOI: 10.1016/j.isci.2023.108050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 07/24/2023] [Accepted: 09/22/2023] [Indexed: 10/26/2023] Open
Abstract
The organization of fear memory involves the participation of multiple brain regions. However, it is largely unknown how fear memory is formed, which circuit pathways are used for "printing" memory engrams across brain regions, and the role of identified brain circuits in memory retrieval. With advanced genetic methods, we combinatorially blocked presynaptic output and manipulated N-methyl-D-aspartate receptor (NMDAR) in the basolateral amygdala (BLA) and medial prefrontal cortex (mPFC) before and after cued fear conditioning. Further, we tagged fear-activated neurons during associative learning for optogenetic memory recall. We found that presynaptic mPFC and postsynaptic BLA NMDARs are required for fear memory formation, but not expression. Our results provide strong evidence that NMDAR-dependent synaptic plasticity drives multi-trace systems consolidation for the sequential printing of fear memory engrams from BLA to mPFC and, subsequently, to the other regions, for flexible memory retrieval.
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Affiliation(s)
- Ilaria Bertocchi
- Department of Molecular Neurobiology, Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany
- Department of Neuroscience "Rita Levi Montalcini", Neuroscience Institute Cavalieri Ottolenghi (NICO), University of Turin, 10043 Turin, Italy
| | - Florbela Rocha-Almeida
- Division of Neurosciences, University Pablo de Olavide, Ctra. de Utrera, km. 1 41013 Seville, Spain
| | | | - Marco Cambiaghi
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Strada le Grazie 8, Verona, Italy
| | - Alejandro Carretero-Guillén
- Laboratory of Brain Circuits Therapeutics, Achucarro Basque Center for Neuroscience, Science Park of the UPV/EHU, Sede Building, Barrio Sarriena, s/n, 48940 Leioa, Spain
| | - Paolo Botta
- CNS drug development, Copenhagen, Capital Region, Denmark
| | - Godwin K. Dogbevia
- Department of Molecular Neurobiology, Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany
- Health Canada, 70 Colombine Driveway, Ottawa, ON K1A0K9, Canada
| | - Mario Treviño
- Department of Molecular Neurobiology, Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany
- Laboratorio de Plasticidad Cortical y Aprendizaje Perceptual, Instituto de Neurociencias, Universidad de Guadalajara, Guadalajara, Mexico
| | - Paolo Mele
- Department of Neuroscience "Rita Levi Montalcini", Neuroscience Institute Cavalieri Ottolenghi (NICO), University of Turin, 10043 Turin, Italy
| | - Alessandra Oberto
- Department of Neuroscience "Rita Levi Montalcini", Neuroscience Institute Cavalieri Ottolenghi (NICO), University of Turin, 10043 Turin, Italy
| | - Matthew E. Larkum
- NeuroCure, Charité-Universitatsmedizin, Virchowweg 6, 10117 Berlin, Germany
| | - Agnes Gruart
- Division of Neurosciences, University Pablo de Olavide, Ctra. de Utrera, km. 1 41013 Seville, Spain
| | - Rolf Sprengel
- Department of Molecular Neurobiology, Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany
| | | | - Mazahir T. Hasan
- Department of Molecular Neurobiology, Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany
- Laboratory of Brain Circuits Therapeutics, Achucarro Basque Center for Neuroscience, Science Park of the UPV/EHU, Sede Building, Barrio Sarriena, s/n, 48940 Leioa, Spain
- Ikerbasque – Basque Foundation for Science, Bilbao, Spain
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16
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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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17
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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: 0] [Impact Index Per Article: 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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18
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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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19
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Gebicke-Haerter PJ. The computational power of the human brain. Front Cell Neurosci 2023; 17:1220030. [PMID: 37608987 PMCID: PMC10441807 DOI: 10.3389/fncel.2023.1220030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 07/05/2023] [Indexed: 08/24/2023] Open
Abstract
At the end of the 20th century, analog systems in computer science have been widely replaced by digital systems due to their higher computing power. Nevertheless, the question keeps being intriguing until now: is the brain analog or digital? Initially, the latter has been favored, considering it as a Turing machine that works like a digital computer. However, more recently, digital and analog processes have been combined to implant human behavior in robots, endowing them with artificial intelligence (AI). Therefore, we think it is timely to compare mathematical models with the biology of computation in the brain. To this end, digital and analog processes clearly identified in cellular and molecular interactions in the Central Nervous System are highlighted. But above that, we try to pinpoint reasons distinguishing in silico computation from salient features of biological computation. First, genuinely analog information processing has been observed in electrical synapses and through gap junctions, the latter both in neurons and astrocytes. Apparently opposed to that, neuronal action potentials (APs) or spikes represent clearly digital events, like the yes/no or 1/0 of a Turing machine. However, spikes are rarely uniform, but can vary in amplitude and widths, which has significant, differential effects on transmitter release at the presynaptic terminal, where notwithstanding the quantal (vesicular) release itself is digital. Conversely, at the dendritic site of the postsynaptic neuron, there are numerous analog events of computation. Moreover, synaptic transmission of information is not only neuronal, but heavily influenced by astrocytes tightly ensheathing the majority of synapses in brain (tripartite synapse). At least at this point, LTP and LTD modifying synaptic plasticity and believed to induce short and long-term memory processes including consolidation (equivalent to RAM and ROM in electronic devices) have to be discussed. The present knowledge of how the brain stores and retrieves memories includes a variety of options (e.g., neuronal network oscillations, engram cells, astrocytic syncytium). Also epigenetic features play crucial roles in memory formation and its consolidation, which necessarily guides to molecular events like gene transcription and translation. In conclusion, brain computation is not only digital or analog, or a combination of both, but encompasses features in parallel, and of higher orders of complexity.
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Affiliation(s)
- Peter J. Gebicke-Haerter
- Institute of Psychopharmacology, Central Institute of Mental Health, Faculty of Medicine, University of Heidelberg, Mannheim, Germany
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20
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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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21
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Terranova JI, Yokose J, Osanai H, Ogawa SK, Kitamura T. Systems consolidation induces multiple memory engrams for a flexible recall strategy in observational fear memory in male mice. Nat Commun 2023; 14:3976. [PMID: 37407567 DOI: 10.1038/s41467-023-39718-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 06/20/2023] [Indexed: 07/07/2023] Open
Abstract
Observers learn to fear the context in which they witnessed a demonstrator's aversive experience, called observational contextual fear conditioning (CFC). The neural mechanisms governing whether recall of the observational CFC memory occurs from the observer's own or from the demonstrator's point of view remain unclear. Here, we show in male mice that recent observational CFC memory is recalled in the observer's context only, but remote memory is recalled in both observer and demonstrator contexts. Recall of recent memory in the observer's context requires dorsal hippocampus activity, while recall of remote memory in both contexts requires the medial prefrontal cortex (mPFC)-basolateral amygdala pathway. Although mPFC neurons activated by observational CFC are involved in remote recall in both contexts, distinct mPFC subpopulations regulate remote recall in each context. Our data provide insights into a flexible recall strategy and the functional reorganization of circuits and memory engram cells underlying observational CFC memory.
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Affiliation(s)
- Joseph I Terranova
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
- Department of Anatomy, Midwestern University, Downers Grove, IL, 60615, USA
| | - Jun Yokose
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Hisayuki Osanai
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Sachie K Ogawa
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Takashi Kitamura
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA.
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA.
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22
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Andrade V, Wong-Guerra M, Cortés N, Pastor G, González A, Calfío C, Guzmán-Martínez L, Navarrete LP, Ramos-Escobar N, Morales I, Santander R, Andrades-Lagos J, Bacho M, Rojo LE, Maccioni RB. Scaling the Andean Shilajit: A Novel Neuroprotective Agent for Alzheimer's Disease. Pharmaceuticals (Basel) 2023; 16:960. [PMID: 37513872 PMCID: PMC10383824 DOI: 10.3390/ph16070960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 05/12/2023] [Accepted: 06/28/2023] [Indexed: 07/30/2023] Open
Abstract
Alzheimer's disease (AD) is a multifactorial neurodegenerative disorder without a cure, despite the enormous number of investigations and therapeutic approaches. AD is a consequence of microglial responses to "damage signals", such as aggregated tau oligomers, which trigger a neuro-inflammatory reaction, promoting the misfolding of cytoskeleton structure. Since AD is the most prevalent cause of dementia in the elderly (>60 years old), new treatments are essential to improve the well-being of affected subjects. The pharmaceutical industry has not developed new drugs with efficacy for controlling AD. In this context, major attention has been given to nutraceuticals and novel bioactive compounds, such as molecules from the Andean Shilajit (AnSh), obtained from the Andes of Chile. Primary cultures of rat hippocampal neurons and mouse neuroblastoma cells were evaluated to examine the functional and neuroprotective role of different AnSh fractions. Our findings show that AnSh fractions increase the number and length of neuronal processes at a differential dose. All fractions were viable in neurons. The AnSh fractions inhibit tau self-aggregation after 10 days of treatment. Finally, we identified two candidate molecules in M3 fractions assayed by UPLC/MS. Our research points to a novel AnSh-derived fraction that is helpful in AD. Intensive work toward elucidation of the molecular mechanisms is being carried out. AnSh is an alternative for AD treatment or as a coadjuvant for an effective treatment.
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Affiliation(s)
- Víctor Andrade
- Laboratory of Neuroscience and Functional Medicine, International Center for Biomedicine, Faculty of Sciences, University of Chile, Santiago 7800003, Chile
- Division of Neurogenetics and Molecular Psychiatry, Department of Psychiatry and Psychotherapy, Medical Faculty, University of Cologne, 50923 Köln, Germany
- Department of Neurodegenerative Diseases and Geriatric Psychiatry, University Hospital Bonn, 53127 Bonn, Germany
| | - Maylin Wong-Guerra
- Laboratory of Neuroscience and Functional Medicine, International Center for Biomedicine, Faculty of Sciences, University of Chile, Santiago 7800003, Chile
- Laboratory of Toxicology and Metabolism, Faculty of Chemistry and Biology, University of Santiago of Chile, Santiago 9170022, Chile
| | - Nicole Cortés
- Laboratory of Neuroscience and Functional Medicine, International Center for Biomedicine, Faculty of Sciences, University of Chile, Santiago 7800003, Chile
| | - Gabriela Pastor
- Laboratory of Neuroscience and Functional Medicine, International Center for Biomedicine, Faculty of Sciences, University of Chile, Santiago 7800003, Chile
- Laboratory of Toxicology and Metabolism, Faculty of Chemistry and Biology, University of Santiago of Chile, Santiago 9170022, Chile
| | - Andrea González
- Laboratory of Neuroscience and Functional Medicine, International Center for Biomedicine, Faculty of Sciences, University of Chile, Santiago 7800003, Chile
| | - Camila Calfío
- Laboratory of Neuroscience and Functional Medicine, International Center for Biomedicine, Faculty of Sciences, University of Chile, Santiago 7800003, Chile
| | - Leonardo Guzmán-Martínez
- Laboratory of Neuroscience and Functional Medicine, International Center for Biomedicine, Faculty of Sciences, University of Chile, Santiago 7800003, Chile
| | - Leonardo P Navarrete
- Laboratory of Neuroscience and Functional Medicine, International Center for Biomedicine, Faculty of Sciences, University of Chile, Santiago 7800003, Chile
- Biochemistry School, Faculty of Health Sciences, Andres Bello University, Santiago 8370035, Chile
| | - Nicolas Ramos-Escobar
- Laboratory of Neuroscience and Functional Medicine, International Center for Biomedicine, Faculty of Sciences, University of Chile, Santiago 7800003, Chile
| | - Inelia Morales
- Laboratory of Neuroscience and Functional Medicine, International Center for Biomedicine, Faculty of Sciences, University of Chile, Santiago 7800003, Chile
| | - Rocío Santander
- Laboratory of Kinetics and Photochemistry, Faculty of Chemistry and Biology, University of Santiago of Chile, Santiago 9170022, Chile
| | - Juan Andrades-Lagos
- Facultad de Medicina y Ciencia, Universidad San Sebastián, Santiago 7510157, Chile
- Drug Development Laboratory, Faculty of Chemical and Pharmaceutical Sciences, University of Chile, Santiago 8380492, Chile
| | - Mitchell Bacho
- Organic and Organometallic Synthesis Laboratory, Faculty of Chemistry, Andrés Bello University, Santiago 8370186, Chile
- Laboratory of Natural Resources, Faculty of Sciences, University of Chile, Santiago 7750000, Chile
| | - Leonel E Rojo
- Laboratory of Toxicology and Metabolism, Faculty of Chemistry and Biology, University of Santiago of Chile, Santiago 9170022, Chile
| | - Ricardo Benjamín Maccioni
- Laboratory of Neuroscience and Functional Medicine, International Center for Biomedicine, Faculty of Sciences, University of Chile, Santiago 7800003, Chile
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23
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Wang W, Wang Z, Cao J, Dong Y, Chen Y. Roles of Rac1-Dependent Intrinsic Forgetting in Memory-Related Brain Disorders: Demon or Angel. Int J Mol Sci 2023; 24:10736. [PMID: 37445914 DOI: 10.3390/ijms241310736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 06/14/2023] [Accepted: 06/21/2023] [Indexed: 07/15/2023] Open
Abstract
Animals are required to handle daily massive amounts of information in an ever-changing environment, and the resulting memories and experiences determine their survival and development, which is critical for adaptive evolution. However, intrinsic forgetting, which actively deletes irrelevant information, is equally important for memory acquisition and consolidation. Recently, it has been shown that Rac1 activity plays a key role in intrinsic forgetting, maintaining the balance of the brain's memory management system in a controlled manner. In addition, dysfunctions of Rac1-dependent intrinsic forgetting may contribute to memory deficits in neurological and neurodegenerative diseases. Here, these new findings will provide insights into the neurobiology of memory and forgetting, pathological mechanisms and potential therapies for brain disorders that alter intrinsic forgetting mechanisms.
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Affiliation(s)
- Wei Wang
- Neurobiology Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Zixu Wang
- Neurobiology Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Jing Cao
- Neurobiology Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Yulan Dong
- Neurobiology Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Yaoxing Chen
- Neurobiology Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
- Key Laboratory of Precision Nutrition and Food Quality, Key Laboratory of Functional Dairy, Ministry of Education, Beijing Laboratory of Food Quality and Safety, Department of Nutrition and Health, China Agricultural University, Beijing 100083, China
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24
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Li JY, Xu Y, Wang DG, Wang JH. The interconnection and function of associative memory neurons are upregulated for memory strengthening. Front Neural Circuits 2023; 17:1189907. [PMID: 37396398 PMCID: PMC10308380 DOI: 10.3389/fncir.2023.1189907] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 05/16/2023] [Indexed: 07/04/2023] Open
Abstract
Memories associated to signals have been proven to rely on the recruitment of associative memory neurons that are featured by mutual synapse innervations among cross-modal cortices. Whether the consolidation of associative memory is endorsed by the upregulation of associative memory neurons in an intramodal cortex remains to be examined. The function and interconnection of associative memory neurons were investigated by in vivo electrophysiology and adeno-associated virus-mediated neural tracing in those mice that experienced associative learning by pairing the whisker tactile signal and the olfactory signal. Our results show that odorant-induced whisker motion as a type of associative memory is coupled with the enhancement of whisking-induced whisker motion. In addition to some barrel cortical neurons encoding both whisker and olfactory signals, i.e., their recruitment as associative memory neurons, the synapse interconnection and spike-encoding capacity of associative memory neurons within the barrel cortex are upregulated. These upregulated alternations were partially observed in the activity-induced sensitization. In summary, associative memory is mechanistically based on the recruitment of associative memory neurons and the upregulation of their interactions in intramodal cortices.
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25
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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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26
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Zichó K, Sos KE, Papp P, Barth AM, Misák E, Orosz Á, Mayer MI, Sebestény RZ, Nyiri G. Fear memory recall involves hippocampal somatostatin interneurons. PLoS Biol 2023; 21:e3002154. [PMID: 37289847 DOI: 10.1371/journal.pbio.3002154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 05/09/2023] [Indexed: 06/10/2023] Open
Abstract
Fear-related memory traces are encoded by sparse populations of hippocampal principal neurons that are recruited based on their inhibitory-excitatory balance during memory formation. Later, the reactivation of the same principal neurons can recall the memory. The details of this mechanism are still unclear. Here, we investigated whether disinhibition could play a major role in this process. Using optogenetic behavioral experiments, we found that when fear was associated with the inhibition of mouse hippocampal somatostatin positive interneurons, the re-inhibition of the same interneurons could recall fear memory. Pontine nucleus incertus neurons selectively inhibit hippocampal somatostatin cells. We also found that when fear was associated with the activity of these incertus neurons or fibers, the reactivation of the same incertus neurons or fibers could also recall fear memory. These incertus neurons showed correlated activity with hippocampal principal neurons during memory recall and were strongly innervated by memory-related neocortical centers, from which the inputs could also control hippocampal disinhibition in vivo. Nonselective inhibition of these mouse hippocampal somatostatin or incertus neurons impaired memory recall. Our data suggest a novel disinhibition-based memory mechanism in the hippocampus that is supported by local somatostatin interneurons and their pontine brainstem inputs.
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Affiliation(s)
- Krisztián Zichó
- Laboratory of Cerebral Cortex Research, Institute of Experimental Medicine, Budapest, Hungary
- János Szentágothai Doctoral School of Neurosciences, Semmelweis University, Budapest, Hungary
| | - Katalin E Sos
- Laboratory of Cerebral Cortex Research, Institute of Experimental Medicine, Budapest, Hungary
| | - Péter Papp
- Laboratory of Cerebral Cortex Research, Institute of Experimental Medicine, Budapest, Hungary
| | - Albert M Barth
- Laboratory of Cerebral Cortex Research, Institute of Experimental Medicine, Budapest, Hungary
| | - Erik Misák
- Laboratory of Cerebral Cortex Research, Institute of Experimental Medicine, Budapest, Hungary
| | - Áron Orosz
- Laboratory of Cerebral Cortex Research, Institute of Experimental Medicine, Budapest, Hungary
| | - Márton I Mayer
- Laboratory of Cerebral Cortex Research, Institute of Experimental Medicine, Budapest, Hungary
- János Szentágothai Doctoral School of Neurosciences, Semmelweis University, Budapest, Hungary
| | - Réka Z Sebestény
- Laboratory of Cerebral Cortex Research, Institute of Experimental Medicine, Budapest, Hungary
| | - Gábor Nyiri
- Laboratory of Cerebral Cortex Research, Institute of Experimental Medicine, Budapest, Hungary
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27
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Malakasis N, Chavlis S, Poirazi P. Synaptic turnover promotes efficient learning in bio-realistic spiking neural networks. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.22.541722. [PMID: 37292929 PMCID: PMC10245885 DOI: 10.1101/2023.05.22.541722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
While artificial machine learning systems achieve superhuman performance in specific tasks such as language processing, image and video recognition, they do so use extremely large datasets and huge amounts of power. On the other hand, the brain remains superior in several cognitively challenging tasks while operating with the energy of a small lightbulb. We use a biologically constrained spiking neural network model to explore how the neural tissue achieves such high efficiency and assess its learning capacity on discrimination tasks. We found that synaptic turnover, a form of structural plasticity, which is the ability of the brain to form and eliminate synapses continuously, increases both the speed and the performance of our network on all tasks tested. Moreover, it allows accurate learning using a smaller number of examples. Importantly, these improvements are most significant under conditions of resource scarcity, such as when the number of trainable parameters is halved and when the task difficulty is increased. Our findings provide new insights into the mechanisms that underlie efficient learning in the brain and can inspire the development of more efficient and flexible machine learning algorithms.
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Affiliation(s)
- Nikos Malakasis
- School of Medicine, University of Crete, Heraklion 70013, Greece
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion 70013, Greece
| | - Spyridon Chavlis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion 70013, Greece
| | - Panayiota Poirazi
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion 70013, Greece
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28
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Nebeling FC, Poll S, Justus LC, Steffen J, Keppler K, Mittag M, Fuhrmann M. Microglial motility is modulated by neuronal activity and correlates with dendritic spine plasticity in the hippocampus of awake mice. eLife 2023; 12:83176. [PMID: 36749020 PMCID: PMC9946443 DOI: 10.7554/elife.83176] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 02/03/2023] [Indexed: 02/08/2023] Open
Abstract
Microglia, the resident immune cells of the brain, play a complex role in health and disease. They actively survey the brain parenchyma by physically interacting with other cells and structurally shaping the brain. Yet, the mechanisms underlying microglial motility and significance for synapse stability, especially in the hippocampus during adulthood, remain widely unresolved. Here, we investigated the effect of neuronal activity on microglial motility and the implications for the formation and survival of dendritic spines on hippocampal CA1 neurons in vivo. We used repetitive two-photon in vivo imaging in the hippocampus of awake and anesthetized mice to simultaneously study the motility of microglia and their interaction with dendritic spines. We found that CA3 to CA1 input is sufficient to modulate microglial process motility. Simultaneously, more dendritic spines emerged in mice after awake compared to anesthetized imaging. Interestingly, the rate of microglial contacts with individual dendritic spines and dendrites was associated with the stability, removal, and emergence of dendritic spines. These results suggest that microglia might sense neuronal activity via neurotransmitter release and actively participate in synaptic rewiring of the hippocampal neural network during adulthood. Further, this study has profound relevance for hippocampal learning and memory processes.
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Affiliation(s)
| | - Stefanie Poll
- Neuroimmunology and Imaging Group, German Center for Neurodegenerative DiseasesBonnGermany
| | - Lena Christine Justus
- Neuroimmunology and Imaging Group, German Center for Neurodegenerative DiseasesBonnGermany
| | - Julia Steffen
- Neuroimmunology and Imaging Group, German Center for Neurodegenerative DiseasesBonnGermany
| | - Kevin Keppler
- Light Microscopy Facility, German Center for Neurodegenerative DiseasesBonnGermany
| | - Manuel Mittag
- Neuroimmunology and Imaging Group, German Center for Neurodegenerative DiseasesBonnGermany
| | - Martin Fuhrmann
- Neuroimmunology and Imaging Group, German Center for Neurodegenerative DiseasesBonnGermany
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29
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Zhu Y, Zeng Y, Ren J, Zhang L, Chen C, Fernandez G, Qin S. Emotional learning retroactively promotes memory integration through rapid neural reactivation and reorganization. eLife 2022; 11:e60190. [PMID: 36476501 PMCID: PMC9815824 DOI: 10.7554/elife.60190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 12/06/2022] [Indexed: 12/13/2022] Open
Abstract
Neutral events preceding emotional experiences can be better remembered, likely by assigning them as significant to guide possible use in future. Yet, the neurobiological mechanisms of how emotional learning enhances memory for past mundane events remain unclear. By two behavioral studies and one functional magnetic resonance imaging study with an adapted sensory preconditioning paradigm, we show rapid neural reactivation and connectivity changes underlying emotion-charged retroactive memory enhancement. Behaviorally, emotional learning retroactively enhanced initial memory for neutral associations across the three studies. Neurally, emotional learning potentiated trial-specific reactivation of overlapping neural traces in the hippocampus and stimulus-relevant neocortex. It further induced rapid hippocampal-neocortical functional reorganization supporting such retroactive memory benefit, as characterized by enhanced hippocampal-neocortical coupling modulated by the amygdala during emotional learning, and a shift of hippocampal connectivity from stimulus-relevant neocortex to distributed transmodal prefrontal-parietal areas at post-learning rests. Together, emotional learning retroactively promotes memory integration for past neutral events through stimulating trial-specific reactivation of overlapping representations and reorganization of associated memories into an integrated network to foster its priority for future use.
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Affiliation(s)
- Yannan Zhu
- State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal UniversityBeijingChina
- Beijing Key Laboratory of Brain Imaging and Connectomics, Beijing Normal UniversityBeijingChina
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical CenterNijmegenNetherlands
| | - Yimeng Zeng
- State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal UniversityBeijingChina
- Beijing Key Laboratory of Brain Imaging and Connectomics, Beijing Normal UniversityBeijingChina
| | - Jingyuan Ren
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical CenterNijmegenNetherlands
| | - Lingke Zhang
- State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal UniversityBeijingChina
- Beijing Key Laboratory of Brain Imaging and Connectomics, Beijing Normal UniversityBeijingChina
| | - Changming Chen
- School of Education, Chongqing Normal UniversityChongqingChina
| | - Guillen Fernandez
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical CenterNijmegenNetherlands
| | - Shaozheng Qin
- State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal UniversityBeijingChina
- Beijing Key Laboratory of Brain Imaging and Connectomics, Beijing Normal UniversityBeijingChina
- Chinese Institute for Brain ResearchBeijingChina
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30
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Fan S, Qi L, Li J, Liu S, Li R, Zhan T, Li X, Wu D, Lau P, Qiu B, Bi G, Ding W. Accelerating Neurite Growth and Directing Neuronal Connections Constrained by 3D Porous Microtubes. NANO LETTERS 2022; 22:8991-8999. [PMID: 36327196 DOI: 10.1021/acs.nanolett.2c03232] [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: 06/16/2023]
Abstract
Investigation of neural growth and connection is crucial in the field of neural tissue engineering. Here, using a femtosecond laser direct writing (fs-DLW) technique, we propose a directionally aligned porous microtube array as a culture system for accelerating the growth of neurons and directing the connection of neurites. These microtubes exhibited an unprecedented guidance effect toward the outgrowth of primary embryonic rat hippocampal neurons, with a wrap resembling the myelin sheaths of neurons. The speed of neurite growth inside these microtubes was significantly faster than that outside these microtubes. We also achieved selective/directing connection of neural networks inside the magnetic microtubes via precise microtube delivery to a gap between two neural clusters. This work not only proposes a powerful microtube platform for accelerated growth of neurons but also offers a new idea for constructing biological neural circuits by arranging the size, location, and pattern of microtubes.
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Affiliation(s)
- Shengying Fan
- Department of Electronic Engineering and Information Science, University of Science and Technology of China, Hefei, Anhui 230026, China
- Department of Oncology, the First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230001, China
| | - Lei Qi
- Institute of Artificial Intelligence, Hefei Comprehensive National Science Center, Hefei, Anhui 230026, China
| | - Jiawen Li
- Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes, CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Shunli Liu
- Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes, CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Rui Li
- Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes, CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Tongzhou Zhan
- Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes, CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Xiaowei Li
- CAS Key Laboratory of Brain Function and Disease, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Dong Wu
- Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes, CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Pakming Lau
- Institute of Artificial Intelligence, Hefei Comprehensive National Science Center, Hefei, Anhui 230026, China
- CAS Key Laboratory of Brain Function and Disease, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Bensheng Qiu
- Department of Electronic Engineering and Information Science, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Guoqiang Bi
- CAS Key Laboratory of Brain Function and Disease, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Weiping Ding
- Department of Oncology, the First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230001, China
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31
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Chowdhury A, Luchetti A, Fernandes G, Filho DA, Kastellakis G, Tzilivaki A, Ramirez EM, Tran MY, Poirazi P, Silva AJ. A locus coeruleus-dorsal CA1 dopaminergic circuit modulates memory linking. Neuron 2022; 110:3374-3388.e8. [PMID: 36041433 PMCID: PMC10508214 DOI: 10.1016/j.neuron.2022.08.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 01/07/2022] [Accepted: 07/31/2022] [Indexed: 11/20/2022]
Abstract
Individual memories are often linked so that the recall of one triggers the recall of another. For example, contextual memories acquired close in time can be linked, and this is known to depend on a temporary increase in excitability that drives the overlap between dorsal CA1 (dCA1) hippocampal ensembles that encode the linked memories. Here, we show that locus coeruleus (LC) cells projecting to dCA1 have a key permissive role in contextual memory linking, without affecting contextual memory formation, and that this effect is mediated by dopamine. Additionally, we found that LC-to-dCA1-projecting neurons modulate the excitability of dCA1 neurons and the extent of overlap between dCA1 memory ensembles as well as the stability of coactivity patterns within these ensembles. This discovery of a neuromodulatory system that specifically affects memory linking without affecting memory formation reveals a fundamental separation between the brain mechanisms modulating these two distinct processes.
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Affiliation(s)
- Ananya Chowdhury
- Departments of Neurobiology, Psychiatry & Biobehavioral Sciences, and Psychology, Integrative Center for Learning and Memory, and Brain Research Institute, UCLA, Los Angeles, CA 90095
| | - Alessandro Luchetti
- Departments of Neurobiology, Psychiatry & Biobehavioral Sciences, and Psychology, Integrative Center for Learning and Memory, and Brain Research Institute, UCLA, Los Angeles, CA 90095
| | - Giselle Fernandes
- Departments of Neurobiology, Psychiatry & Biobehavioral Sciences, and Psychology, Integrative Center for Learning and Memory, and Brain Research Institute, UCLA, Los Angeles, CA 90095
| | - Daniel Almeida Filho
- Departments of Neurobiology, Psychiatry & Biobehavioral Sciences, and Psychology, Integrative Center for Learning and Memory, and Brain Research Institute, UCLA, Los Angeles, CA 90095
| | - George Kastellakis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology, Hellas (FORTH), Vassilica Vouton, PO Box 1527, GR 711 10 Heraklion, Crete, Greece
| | - Alexandra Tzilivaki
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology, Hellas (FORTH), Vassilica Vouton, PO Box 1527, GR 711 10 Heraklion, Crete, Greece
- Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health Charitéplatz 1, 10117 Berlin Germany
- Einstein Center for Neurosciences Berlin Charitéplatz 1, 10117 Berlin Germany
- Neurocure Cluster of Excellence Charitéplatz 1, 10117 Berlin, Germany
| | - Erica M Ramirez
- Departments of Neurobiology, Psychiatry & Biobehavioral Sciences, and Psychology, Integrative Center for Learning and Memory, and Brain Research Institute, UCLA, Los Angeles, CA 90095
| | - Mary Y Tran
- Departments of Neurobiology, Psychiatry & Biobehavioral Sciences, and Psychology, Integrative Center for Learning and Memory, and Brain Research Institute, UCLA, Los Angeles, CA 90095
| | - Panayiota Poirazi
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology, Hellas (FORTH), Vassilica Vouton, PO Box 1527, GR 711 10 Heraklion, Crete, Greece
| | - Alcino J Silva
- Departments of Neurobiology, Psychiatry & Biobehavioral Sciences, and Psychology, Integrative Center for Learning and Memory, and Brain Research Institute, UCLA, Los Angeles, CA 90095
- Lead contact
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32
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Sardoo AM, Zhang S, Ferraro TN, Keck TM, Chen Y. Decoding brain memory formation by single-cell RNA sequencing. Brief Bioinform 2022; 23:6713514. [PMID: 36156112 PMCID: PMC9677489 DOI: 10.1093/bib/bbac412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 07/10/2022] [Accepted: 08/25/2022] [Indexed: 12/14/2022] Open
Abstract
To understand how distinct memories are formed and stored in the brain is an important and fundamental question in neuroscience and computational biology. A population of neurons, termed engram cells, represents the physiological manifestation of a specific memory trace and is characterized by dynamic changes in gene expression, which in turn alters the synaptic connectivity and excitability of these cells. Recent applications of single-cell RNA sequencing (scRNA-seq) and single-nucleus RNA sequencing (snRNA-seq) are promising approaches for delineating the dynamic expression profiles in these subsets of neurons, and thus understanding memory-specific genes, their combinatorial patterns and regulatory networks. The aim of this article is to review and discuss the experimental and computational procedures of sc/snRNA-seq, new studies of molecular mechanisms of memory aided by sc/snRNA-seq in human brain diseases and related mouse models, and computational challenges in understanding the regulatory mechanisms underlying long-term memory formation.
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Affiliation(s)
- Atlas M Sardoo
- Department of Biological & Biomedical Sciences, Rowan University, Glassboro, NJ 08028, USA
| | - Shaoqiang Zhang
- College of Computer and Information Engineering, Tianjin Normal University, Tianjin 300387, China
| | - Thomas N Ferraro
- Department of Biomedical Sciences, Cooper Medical School of Rowan University, Camden, NJ 08103, USA
| | - Thomas M Keck
- Department of Biological & Biomedical Sciences, Rowan University, Glassboro, NJ 08028, USA,Department of Chemistry & Biochemistry, Rowan University, Glassboro, NJ 08028, USA
| | - Yong Chen
- Corresponding author. Yong Chen, Department of Biological and Biomedical Sciences, Rowan University, Glassboro, NJ 08028, USA. Tel.: +1 856 256 4500; E-mail:
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33
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Amano R, Nakao M, Matsumiya K, Miwakeichi F. A computational model to explore how temporal stimulation patterns affect synapse plasticity. PLoS One 2022; 17:e0275059. [PMID: 36149886 PMCID: PMC9506666 DOI: 10.1371/journal.pone.0275059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 09/09/2022] [Indexed: 11/18/2022] Open
Abstract
Plasticity-related proteins (PRPs), which are synthesized in a synapse activation-dependent manner, are shared by multiple synapses to a limited spatial extent for a specific period. In addition, stimulated synapses can utilize shared PRPs through synaptic tagging and capture (STC). In particular, the phenomenon by which short-lived early long-term potentiation is transformed into long-lived late long-term potentiation using shared PRPs is called “late-associativity,” which is the underlying principle of “cluster plasticity.” We hypothesized that the competitive capture of PRPs by multiple synapses modulates late-associativity and affects the fate of each synapse in terms of whether it is integrated into a synapse cluster. We tested our hypothesis by developing a computational model to simulate STC, late-associativity, and the competitive capture of PRPs. The experimental results obtained using the model revealed that the number of competing synapses, timing of stimulation to each synapse, and basal PRP level in the dendritic compartment altered the effective temporal window of STC and influenced the conditions under which late-associativity occurs. Furthermore, it is suggested that the competitive capture of PRPs results in the selection of synapses to be integrated into a synapse cluster via late-associativity.
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Affiliation(s)
- Ryota Amano
- Graduate School of Information Sciences, Tohoku University, Sendai, Japan
- * E-mail:
| | - Mitsuyuki Nakao
- Graduate School of Information Sciences, Tohoku University, Sendai, Japan
| | | | - Fumikazu Miwakeichi
- Graduate School of Information Sciences, Tohoku University, Sendai, Japan
- Department of Statistical Modeling, The Institute of Statistical Mathematics, Tachikawa-Shi, Japan
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34
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Bickle J, De Sousa AF, Silva AJ. New research tools suggest a “levels-less” image of the behaving organism and dissolution of the reduction vs. anti-reduction dispute. Front Psychol 2022; 13:990316. [PMID: 36110269 PMCID: PMC9470241 DOI: 10.3389/fpsyg.2022.990316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2022] [Accepted: 08/05/2022] [Indexed: 11/13/2022] Open
Abstract
A kind of “ruthless reductionism” characterized the experimental practices of the first two decades of molecular and cellular cognition (MCC). More recently, new research tools have expanded experimental practices in this field, enabling researchers to image and manipulate individual molecular mechanisms in behaving organisms with an unprecedented temporal, sub-cellular, cellular, and even circuit-wide specificity. These tools dramatically expand the range and reach of experiments in MCC, and in doing so they may help us transcend the worn-out and counterproductive debates about “reductionism” and “emergence” that divide neuroscientists and philosophers alike. We describe examples of these new tools and illustrate their practical power by presenting an exemplary recent case of MCC research using them. From these tools and results, we provide an initial sketch of a new image of the behaving organism in its full causal-interactive complexity, with its molecules, cells, and circuits combined within the single system that it is. This new image stands in opposition to the traditional “levels” image of the behaving organism, and even the initial sketch we provide of it here offers hope for avoiding the dreary metaphysical debates about “emergence” and “downward causation,” and even the reduction vs. anti-reduction dispute, all dependent upon the familiar “levels” image.
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Affiliation(s)
- John Bickle
- Department of Philosophy and Religion, Shackouls Honors College, Mississippi State University, Starkville, MS, United States
- Department of Advanced Biomedical Education, University of Mississippi Medical Center, Jackson, MS, United States
- *Correspondence: John Bickle,
| | - André F. De Sousa
- Department of Neurobiology, University of California, Los Angeles, Los Angeles, CA, United States
| | - Alcino J. Silva
- Department of Neurobiology, University of California, Los Angeles, Los Angeles, CA, United States
- Department of Psychiatry and Integrative Center for Learning and Memory, UCLA, Los Angeles, CA, United States
- Department of Psychology and Integrative Center for Learning and Memory, UCLA, Los Angeles, CA, United States
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35
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A missense mutation in Kcnc3 causes hippocampal learning deficits in mice. Proc Natl Acad Sci U S A 2022; 119:e2204901119. [PMID: 35881790 PMCID: PMC9351536 DOI: 10.1073/pnas.2204901119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Although a wide variety of genetic tools has been developed to study learning and memory, the molecular basis of memory encoding remains incompletely understood. Here, we undertook an unbiased approach to identify novel genes critical for memory encoding. From a large-scale, in vivo mutagenesis screen using contextual fear conditioning, we isolated in mice a mutant, named Clueless, with spatial learning deficits. A causative missense mutation (G434V) was found in the voltage-gated potassium channel, subfamily C member 3 (Kcnc3) gene in a region that encodes a transmembrane voltage sensor. Generation of a Kcnc3G434V CRISPR mutant mouse confirmed this mutation as the cause of the learning defects. While G434V had no effect on transcription, translation, or trafficking of the channel, electrophysiological analysis of the G434V mutant channel revealed a complete loss of voltage-gated conductance, a broadening of the action potential, and decreased neuronal firing. Together, our findings have revealed a role for Kcnc3 in learning and memory.
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36
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Shridhar S, Mishra P, Narayanan R. Dominant role of adult neurogenesis-induced structural heterogeneities in driving plasticity heterogeneity in dentate gyrus granule cells. Hippocampus 2022; 32:488-516. [PMID: 35561083 PMCID: PMC9322436 DOI: 10.1002/hipo.23422] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 04/21/2022] [Accepted: 04/28/2022] [Indexed: 02/02/2023]
Abstract
Neurons and synapses manifest pronounced variability in the amount of plasticity induced by identical activity patterns. The mechanisms underlying such plasticity heterogeneity, which have been implicated in context‐specific resource allocation during encoding, have remained unexplored. Here, we employed a systematic physiologically constrained parametric search to identify the cellular mechanisms behind plasticity heterogeneity in dentate gyrus granule cells. We used heterogeneous model populations to ensure that our conclusions were not biased by parametric choices in a single hand‐tuned model. We found that each of intrinsic, synaptic, and structural heterogeneities independently yielded heterogeneities in synaptic plasticity profiles obtained with two different induction protocols. However, among the disparate forms of neural‐circuit heterogeneities, our analyses demonstrated the dominance of neurogenesis‐induced structural heterogeneities in driving plasticity heterogeneity in granule cells. We found that strong relationships between neuronal intrinsic excitability and plasticity emerged only when adult neurogenesis‐induced heterogeneities in neural structure were accounted for. Importantly, our analyses showed that it was not imperative that the manifestation of neural‐circuit heterogeneities must translate to heterogeneities in plasticity profiles. Specifically, despite the expression of heterogeneities in structural, synaptic, and intrinsic neuronal properties, similar plasticity profiles were attainable across all models through synergistic interactions among these heterogeneities. We assessed the parametric combinations required for the manifestation of such degeneracy in the expression of plasticity profiles. We found that immature cells showed physiological plasticity profiles despite receiving afferent inputs with weak synaptic strengths. Thus, the high intrinsic excitability of immature granule cells was sufficient to counterbalance their low excitatory drive in the expression of plasticity profile degeneracy. Together, our analyses demonstrate that disparate forms of neural‐circuit heterogeneities could mechanistically drive plasticity heterogeneity, but also caution against treating neural‐circuit heterogeneities as proxies for plasticity heterogeneity. Our study emphasizes the need for quantitatively characterizing the relationship between neural‐circuit and plasticity heterogeneities across brain regions.
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Affiliation(s)
- Sameera Shridhar
- Cellular Neurophysiology Laboratory, Molecular Biophysics Unit, Indian Institute of Science, Bangalore, Karnataka, India
| | - Poonam Mishra
- Cellular Neurophysiology Laboratory, Molecular Biophysics Unit, Indian Institute of Science, Bangalore, Karnataka, India
| | - Rishikesh Narayanan
- Cellular Neurophysiology Laboratory, Molecular Biophysics Unit, Indian Institute of Science, Bangalore, Karnataka, India
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37
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Terranova JI, Yokose J, Osanai H, Marks WD, Yamamoto J, Ogawa SK, Kitamura T. Hippocampal-amygdala memory circuits govern experience-dependent observational fear. Neuron 2022; 110:1416-1431.e13. [PMID: 35139362 PMCID: PMC9035063 DOI: 10.1016/j.neuron.2022.01.019] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 12/10/2021] [Accepted: 01/13/2022] [Indexed: 11/28/2022]
Abstract
The empathic ability to vicariously experience the other's fearful situation, a process called observational fear (OF), is critical to survive in nature and function in society. OF can be facilitated by both prior similar fear experience in the observer and social familiarity with the demonstrator. However, the neural circuit mechanisms of experience-dependent OF (Exp OF) remain unknown. Here, we demonstrate that hippocampal-basolateral amygdala (HPC-BLA) circuits in mice without involving the anterior cingulate cortex, considered a center of OF, mediate Exp OF. Dorsal HPC neurons generate fear memory engram cells in BLA encoding prior similar fear experiences, which are essential for Exp OF. On the other hand, ventral HPC neurons respond to the familiar demonstrator's aversive situation during Exp OF, which reactivates the fear memory engram cells in BLA to elicit Exp OF. Our study provides new insights into the memory engram-dependent perception-action coupling that underlies empathic behaviors like Exp OF.
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Affiliation(s)
- Joseph I Terranova
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jun Yokose
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Hisayuki Osanai
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - William D Marks
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jun Yamamoto
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Sachie K Ogawa
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Takashi Kitamura
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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38
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Shridhar S, Singh VP, Bhatt R, Kundu S, Balaji J. A new paradigm for investigating temporal order memory shows higher order associations are present in recent but not in remote retrieval. Exp Brain Res 2022; 240:611-629. [PMID: 34988597 DOI: 10.1007/s00221-021-06282-7] [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: 10/26/2021] [Accepted: 11/25/2021] [Indexed: 11/30/2022]
Abstract
Memory of a sequence of distinct events requires encoding the temporal order as well as the intervals that separates these events. In this study, using order-place association task where the animal learns to associate the location of the food pellet to the order of entry into the event arena, we probe the nature of temporal order memory in mice. In our task, individual trials become distinct events, as the animal is trained to form a unique association between entry order and a correct location. The inter-trial intervals (> 30 min) are chosen deliberately to minimize the inputs from working memory. We develop this paradigm initially using four order-place associates and later extend it to five paired associates. Our results show that animals not only acquire these explicit (entry order to place) associations but also higher order associations that can only be inferred implicitly (temporal relation between the events) from the temporal order of these events. As an indicator of such higher order learning during the probe trial, the mice exhibit predominantly prospective errors that decline proportionally with temporal distance. On the other hand, prior to acquiring the sequence, the retrospective errors are dominant. In addition, we also tested the nature of such acquisitions when temporal order CS is presented along with flavored pellet as a compound stimulus comprising of order and flavor both simultaneously being paired with location. Results from these experiments indicate that the animal learns both order-place and flavor-place associations. Comparing with pure order-place training, we find that the additional flavor stimulus in a compound training paradigm did not interfere with the ability of the animals to acquire the order-place associations. When tested remotely, pure order-place associations could be retrieved only after a reminder training. Further higher order associations representing the temporal relationship between the events is markedly absent in the remote time.
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Affiliation(s)
- Shruti Shridhar
- Center for Neurosciences, Indian Institute of Science, Bangalore, 560012, India
| | - Vikram Pal Singh
- Center for Neurosciences, Indian Institute of Science, Bangalore, 560012, India
| | - Richa Bhatt
- Center for Neurosciences, Indian Institute of Science, Bangalore, 560012, India
| | - Sankhanava Kundu
- Center for Neurosciences, Indian Institute of Science, Bangalore, 560012, India
| | - J Balaji
- Center for Neurosciences, Indian Institute of Science, Bangalore, 560012, India.
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39
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Holmes NM, Wong FS, Bouchekioua Y, Westbrook RF. Not "either-or" but "which-when": A review of the evidence for integration in sensory preconditioning. Neurosci Biobehav Rev 2021; 132:1197-1204. [PMID: 34718047 DOI: 10.1016/j.neubiorev.2021.10.032] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 09/28/2021] [Accepted: 10/25/2021] [Indexed: 11/30/2022]
Abstract
Sensory preconditioning protocols can be used to assess how the brain integrates memories that share common features. In these protocols, animals are first exposed to pairings of two relatively innocuous stimuli, S2 and S1 (stage 1), and then to pairings of one of these stimuli, S1, with an event of motivational significance (stage 2). Following this training, test presentations of S2 elicit responses appropriate to the motivationally significant event, and these responses are taken to indicate formation of distinct S2-S1 and S1-event memories that are integrated in some way to generate that responding. This paper reviews studies of sensory preconditioning in rats, mice, rabbits and people to determine whether S2-S1 and S1-event memories are integrated through a chaining process at the time of their retrieval (i.e., test presentations of S2 trigger retrieval of S1, and thereby, responses appropriate to the event); or "online" at the time of memory formation (i.e., in stage 2, S1 activates a representation of S2 such that both stimuli associate with the motivationally significant event). It finds that the type of integration is determined by the manner in which stimuli are presented in preconditioning as well as their familiarity. When the stimuli in preconditioning are presented repeatedly and/or serially (i.e., one after the other), the S2-S1 and S1-event memories are chained at the time of retrieval/testing. In contrast, when the stimuli in preconditioning are relatively novel and/or presented simultaneously, the S2-S1 and S1-event memories are integrated online. These statements are related to prior claims regarding the circumstances that promote different types of memory integration and, more generally, mechanisms of information processing in the mammalian brain.
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Affiliation(s)
- Nathan M Holmes
- School of Psychology, University of New South Wales, Sydney, NSW, 2052, Australia.
| | - Francesca S Wong
- School of Psychology, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Youcef Bouchekioua
- School of Medicine, Hokkaido University, Sapporo, Hokkaido, 060-0808, Japan
| | - R Fred Westbrook
- School of Psychology, University of New South Wales, Sydney, NSW, 2052, Australia
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40
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Glas A, Hübener M, Bonhoeffer T, Goltstein PM. Spaced training enhances memory and prefrontal ensemble stability in mice. Curr Biol 2021; 31:4052-4061.e6. [PMID: 34324833 DOI: 10.1016/j.cub.2021.06.085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 06/01/2021] [Accepted: 06/28/2021] [Indexed: 11/15/2022]
Abstract
It is commonly acknowledged that memory is substantially improved when learning is distributed over time, an effect called the "spacing effect". So far it has not been studied how spaced learning affects the neuronal ensembles presumably underlying memory. In the present study, we investigate whether trial spacing increases the stability or size of neuronal ensembles. Mice were trained in the "everyday memory" task, an appetitive, naturalistic, delayed matching-to-place task. Spacing trials by 60 min produced more robust memories than training with shorter or longer intervals. c-Fos labeling and chemogenetic inactivation established the involvement of the dorsomedial prefrontal cortex (dmPFC) in successful memory storage. In vivo calcium imaging of excitatory dmPFC neurons revealed that longer trial spacing increased the similarity of the population activity pattern on subsequent encoding trials and upon retrieval. Conversely, trial spacing did not affect the size of the total neuronal ensemble or the size of subpopulations dedicated to specific task-related behaviors and events. Thus, spaced learning promotes reactivation of prefrontal neuronal ensembles processing episodic-like memories.
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Affiliation(s)
- Annet Glas
- Max Planck Institute of Neurobiology, Am Klopferspitz 18, 82152 Martinsried, Germany; Graduate School of Systemic Neurosciences, Ludwig-Maximilians-Universität München, Großhaderner Straße 2, 82152 Martinsried, Germany
| | - Mark Hübener
- Max Planck Institute of Neurobiology, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Tobias Bonhoeffer
- Max Planck Institute of Neurobiology, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Pieter M Goltstein
- Max Planck Institute of Neurobiology, Am Klopferspitz 18, 82152 Martinsried, Germany.
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41
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de Sousa AF, Chowdhury A, Silva AJ. Dimensions and mechanisms of memory organization. Neuron 2021; 109:2649-2662. [PMID: 34242564 PMCID: PMC8416710 DOI: 10.1016/j.neuron.2021.06.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 04/17/2021] [Accepted: 06/11/2021] [Indexed: 12/31/2022]
Abstract
Memory formation is dynamic in nature, and acquisition of new information is often influenced by previous experiences. Memories sharing certain attributes are known to interact so that retrieval of one increases the likelihood of retrieving the other, raising the possibility that related memories are organized into associative mnemonic structures of interconnected representations. Although the formation and retrieval of single memories have been studied extensively, very little is known about the brain mechanisms that organize and link related memories. Here we review studies that suggest the existence of mnemonic structures in humans and animal models. These studies suggest three main dimensions of experience that can serve to organize related memories: time, space, and perceptual/conceptual similarities. We propose potential molecular, cellular, and systems mechanisms that might support organization of memories according to these dimensions.
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Affiliation(s)
- André F de Sousa
- Departments of Neurobiology, Psychiatry & Biobehavioral Sciences, and Psychology, Integrative Center for Learning and Memory, Brain Research Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Ananya Chowdhury
- Departments of Neurobiology, Psychiatry & Biobehavioral Sciences, and Psychology, Integrative Center for Learning and Memory, Brain Research Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Alcino J Silva
- Departments of Neurobiology, Psychiatry & Biobehavioral Sciences, and Psychology, Integrative Center for Learning and Memory, Brain Research Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA.
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42
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Taylor JE, Cortese A, Barron HC, Pan X, Sakagami M, Zeithamova D. How do we generalize? NEURONS, BEHAVIOR, DATA ANALYSIS AND THEORY 2021; 1:001c.27687. [PMID: 36282996 PMCID: PMC7613724 DOI: 10.51628/001c.27687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Humans and animals are able to generalize or transfer information from previous experience so that they can behave appropriately in novel situations. What mechanisms-computations, representations, and neural systems-give rise to this remarkable ability? The members of this Generative Adversarial Collaboration (GAC) come from a range of academic backgrounds but are all interested in uncovering the mechanisms of generalization. We started out this GAC with the aim of arbitrating between two alternative conceptual accounts: (1) generalization stems from integration of multiple experiences into summary representations that reflect generalized knowledge, and (2) generalization is computed on-the-fly using separately stored individual memories. Across the course of this collaboration, we found that-despite using different terminology and techniques, and although some of our specific papers may provide evidence one way or the other-we in fact largely agree that both of these broad accounts (as well as several others) are likely valid. We believe that future research and theoretical synthesis across multiple lines of research is necessary to help determine the degree to which different candidate generalization mechanisms may operate simultaneously, operate on different scales, or be employed under distinct conditions. Here, as the first step, we introduce some of these candidate mechanisms and we discuss the issues currently hindering better synthesis of generalization research. Finally, we introduce some of our own research questions that have arisen over the course of this GAC, that we believe would benefit from future collaborative efforts.
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Affiliation(s)
- Jessica Elizabeth Taylor
- The Department of Decoded Neurofeedback, Computational Neuroscience Laboratories, Advanced Telecommunications Research Institute International, Kyoto, Japan
| | - Aurelio Cortese
- The Department of Decoded Neurofeedback, Computational Neuroscience Laboratories, Advanced Telecommunications Research Institute International, Kyoto, Japan
- Institute of Cognitive Neuroscience, University College London, UK
| | - Helen C Barron
- Medical Research Council Brain Network Dynamics Unit, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
- Wellcome Centre for Integrative Neuroimaging, University of Oxford, FMRIB, John Radcliffe Hospital, Oxford, UK
| | - Xiaochuan Pan
- Institute for Cognitive Neurodynamics, East China University of Science and Technology, Shanghai, China
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43
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Meenakshi P, Kumar S, Balaji J. In vivo imaging of immediate early gene expression dynamics segregates neuronal ensemble of memories of dual events. Mol Brain 2021; 14:102. [PMID: 34187543 PMCID: PMC8243579 DOI: 10.1186/s13041-021-00798-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 05/27/2021] [Indexed: 11/10/2022] Open
Abstract
Identification of neurons undergoing plasticity in response to external stimuli is one of the pertinent problems in neuroscience. Immediate early genes (IEGs) are widely used as a marker for neuronal plasticity. Here, we model the dynamics of IEG expression as a consecutive, irreversible first-order reaction with a limiting substrate. First, we develop an analytical framework to show that such a model, together with two-photon in vivo imaging of IEG expression, can be used to identify distinct neuronal subsets representing multiple memories. Using the above combination, we show that the expression kinetics, rather than intensity threshold, can be used to identify neuronal ensembles responding to the presentation of two events in vivo. The analytical expression allowed us to segregate the neurons based on their temporal response to one specific behavioural event, thereby improving the ability to detect plasticity related neurons. We image the retrosplenial cortex (RSc) of cfos-GFP transgenic mice to follow the dynamics of cellular changes resulting from contextual fear conditioning behaviour, enabling us to establish a representation of context in RSc at the cellular scale following memory acquisition. Thus, we obtain a general method that distinguishes neurons that took part in multiple temporally separated events by measuring fluorescence of individual neurons in live mice.
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Affiliation(s)
- P Meenakshi
- Centre for Neurosciences, Indian Institute of Science, Bangalore, 560012, India
| | - S Kumar
- Centre for Neurosciences, Indian Institute of Science, Bangalore, 560012, India
| | - J Balaji
- Centre for Neurosciences, Indian Institute of Science, Bangalore, 560012, India.
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44
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Lee JS, Briguglio JJ, Cohen JD, Romani S, Lee AK. The Statistical Structure of the Hippocampal Code for Space as a Function of Time, Context, and Value. Cell 2020; 183:620-635.e22. [DOI: 10.1016/j.cell.2020.09.024] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 05/25/2020] [Accepted: 09/09/2020] [Indexed: 01/22/2023]
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45
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Chen L, Cummings KA, Mau W, Zaki Y, Dong Z, Rabinowitz S, Clem RL, Shuman T, Cai DJ. The role of intrinsic excitability in the evolution of memory: Significance in memory allocation, consolidation, and updating. Neurobiol Learn Mem 2020; 173:107266. [PMID: 32512183 PMCID: PMC7429265 DOI: 10.1016/j.nlm.2020.107266] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 05/28/2020] [Accepted: 05/31/2020] [Indexed: 11/30/2022]
Abstract
Memory is a dynamic process that is continuously regulated by both synaptic and intrinsic neural mechanisms. While numerous studies have shown that synaptic plasticity is important in various types and phases of learning and memory, neuronal intrinsic excitability has received relatively less attention, especially regarding the dynamic nature of memory. In this review, we present evidence demonstrating the importance of intrinsic excitability in memory allocation, consolidation, and updating. We also consider the intricate interaction between intrinsic excitability and synaptic plasticity in shaping memory, supporting both memory stability and flexibility.
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Affiliation(s)
- Lingxuan Chen
- Icahn School of Medicine at Mount Sinai, Department of Neuroscience, New York, New York, 10029, United States
| | - Kirstie A Cummings
- Icahn School of Medicine at Mount Sinai, Department of Neuroscience, New York, New York, 10029, United States
| | - William Mau
- Icahn School of Medicine at Mount Sinai, Department of Neuroscience, New York, New York, 10029, United States
| | - Yosif Zaki
- Icahn School of Medicine at Mount Sinai, Department of Neuroscience, New York, New York, 10029, United States
| | - Zhe Dong
- Icahn School of Medicine at Mount Sinai, Department of Neuroscience, New York, New York, 10029, United States
| | - Sima Rabinowitz
- Icahn School of Medicine at Mount Sinai, Department of Neuroscience, New York, New York, 10029, United States
| | - Roger L Clem
- Icahn School of Medicine at Mount Sinai, Department of Neuroscience, New York, New York, 10029, United States
| | - Tristan Shuman
- Icahn School of Medicine at Mount Sinai, Department of Neuroscience, New York, New York, 10029, United States
| | - Denise J Cai
- Icahn School of Medicine at Mount Sinai, Department of Neuroscience, New York, New York, 10029, United States.
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46
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Kim E, Jeon S, An HK, Kianpour M, Yu SW, Kim JY, Rah JC, Choi H. A magnetically actuated microrobot for targeted neural cell delivery and selective connection of neural networks. SCIENCE ADVANCES 2020; 6:eabb5696. [PMID: 32978164 PMCID: PMC7518876 DOI: 10.1126/sciadv.abb5696] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 08/10/2020] [Indexed: 05/02/2023]
Abstract
There has been a great deal of interest in the development of technologies for actively manipulating neural networks in vitro, providing natural but simplified environments in a highly reproducible manner in which to study brain function and related diseases. Platforms for these in vitro neural networks require precise and selective neural connections at the target location, with minimal external influences, and measurement of neural activity to determine how neurons communicate. Here, we report a neuron-loaded microrobot for selective connection of neural networks via precise delivery to a gap between two neural clusters by an external magnetic field. In addition, the extracellular action potential was propagated from one cluster to the other through the neurons on the microrobot. The proposed technique shows the potential for use in experiments to understand how neurons communicate in the neural network by actively connecting neural clusters.
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Affiliation(s)
- Eunhee Kim
- Department of Robotics Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, South Korea
- DGIST-ETH Microrobot Research Center, DGIST, Daegu 42988, South Korea
| | - Sungwoong Jeon
- Department of Robotics Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, South Korea
- DGIST-ETH Microrobot Research Center, DGIST, Daegu 42988, South Korea
| | - Hyun-Kyu An
- Department of Brain and Cognitive Sciences, DGIST, Daegu 42988, South Korea
| | | | - Seong-Woon Yu
- Department of Brain and Cognitive Sciences, DGIST, Daegu 42988, South Korea
| | - Jin-Young Kim
- Department of Robotics Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, South Korea.
- DGIST-ETH Microrobot Research Center, DGIST, Daegu 42988, South Korea
| | - Jong-Cheol Rah
- Department of Brain and Cognitive Sciences, DGIST, Daegu 42988, South Korea
- Korea Brain Research Institute, Daegu 42988, South Korea
| | - Hongsoo Choi
- Department of Robotics Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, South Korea.
- DGIST-ETH Microrobot Research Center, DGIST, Daegu 42988, South Korea
- Robotics Research Center, DGIST, Daegu 42988, South Korea
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47
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Limbacher T, Legenstein R. Emergence of Stable Synaptic Clusters on Dendrites Through Synaptic Rewiring. Front Comput Neurosci 2020; 14:57. [PMID: 32848681 PMCID: PMC7424032 DOI: 10.3389/fncom.2020.00057] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 05/22/2020] [Indexed: 11/16/2022] Open
Abstract
The connectivity structure of neuronal networks in cortex is highly dynamic. This ongoing cortical rewiring is assumed to serve important functions for learning and memory. We analyze in this article a model for the self-organization of synaptic inputs onto dendritic branches of pyramidal cells. The model combines a generic stochastic rewiring principle with a simple synaptic plasticity rule that depends on local dendritic activity. In computer simulations, we find that this synaptic rewiring model leads to synaptic clustering, that is, temporally correlated inputs become locally clustered on dendritic branches. This empirical finding is backed up by a theoretical analysis which shows that rewiring in our model favors network configurations with synaptic clustering. We propose that synaptic clustering plays an important role in the organization of computation and memory in cortical circuits: we find that synaptic clustering through the proposed rewiring mechanism can serve as a mechanism to protect memories from subsequent modifications on a medium time scale. Rewiring of synaptic connections onto specific dendritic branches may thus counteract the general problem of catastrophic forgetting in neural networks.
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Affiliation(s)
| | - Robert Legenstein
- Institute of Theoretical Computer Science, Graz University of Technology, Graz, Austria
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48
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Tiunova AA, Bezryadnov DV, Gaeva DR, Solodovnikov VS, Anokhin KV. Memory reacquisition deficit: Chicks fail to relearn pharmacologically disrupted associative response. Behav Brain Res 2020; 390:112695. [PMID: 32407820 DOI: 10.1016/j.bbr.2020.112695] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 03/15/2020] [Accepted: 05/04/2020] [Indexed: 11/29/2022]
Abstract
It is generally assumed that if memory is disrupted by pharmacological inhibitors during its consolidation, it can be later acquired afresh. In our experiments, we trained day-old chicks in a one-trial passive avoidance task and interfered with memory formation using protein synthesis inhibitor anisomycin or NMDA receptor antagonist MK-801. Second training was then given to amnestic animals with either the same conditioning stimulus (retraining) or a new one (novel training). Retraining with the same stimulus failed to produce efficient memory at all the examined between-training and training-to-test intervals, while a new conditioned stimulus was learned successfully. We suggest that this memory reacquisition deficit may result from the failure of associative memory co-allocation mechanisms.
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Affiliation(s)
- A A Tiunova
- P. K. Anokhin Research Institute of Normal Physiology, 125315, Moscow, Russia.
| | - D V Bezryadnov
- P. K. Anokhin Research Institute of Normal Physiology, 125315, Moscow, Russia
| | - D R Gaeva
- National Research Center "Kurchatov Institute", 123182, Moscow, Russia
| | - V S Solodovnikov
- P. K. Anokhin Research Institute of Normal Physiology, 125315, Moscow, Russia
| | - K V Anokhin
- P. K. Anokhin Research Institute of Normal Physiology, 125315, Moscow, Russia; Lomonosov Moscow State University, 119991, Moscow,Russia
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Chen N, Tsai TC, Hsu KS. Exposure to Novelty Promotes Long-Term Contextual Fear Memory Formation in Juvenile Mice: Evidence for a Behavioral Tagging. Mol Neurobiol 2020; 57:3956-3968. [DOI: 10.1007/s12035-020-02005-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 06/26/2020] [Indexed: 11/29/2022]
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A time-dependent role for the transcription factor CREB in neuronal allocation to an engram underlying a fear memory revealed using a novel in vivo optogenetic tool to modulate CREB function. Neuropsychopharmacology 2020; 45:916-924. [PMID: 31837649 PMCID: PMC7162924 DOI: 10.1038/s41386-019-0588-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 11/08/2019] [Accepted: 12/04/2019] [Indexed: 12/21/2022]
Abstract
The internal representation of an experience is thought to be encoded by long-lasting physical changes to the brain ("engrams") . Previously, we and others showed within the lateral amygdala (LA), a region critical for auditory conditioned fear, eligible neurons compete against one other for allocation to an engram. Neurons with relatively higher function of the transcription factor CREB were more likely to be allocated to the engram. In these studies, though, CREB function was artificially increased for several days before training. Precisely when increased CREB function is important for allocation remains an unanswered question. Here, we took advantage of a novel optogenetic tool (opto-DN-CREB) to gain spatial and temporal control of CREB function in freely behaving mice. We found increasing CREB function in a small, random population of LA principal neurons in the minutes, but not 24 h, before training was sufficient to enhance memory, likely because these neurons were preferentially allocated to the underlying engram. However, similarly increasing CREB activity in a small population of random LA neurons immediately after training disrupted subsequent memory retrieval, likely by disrupting the precise spatial and temporal patterns of offline post-training neuronal activity and/or function required for consolidation. These findings reveal the importance of the timing of CREB activity in regulating allocation and subsequent memory retrieval, and further, highlight the potential of optogenetic approaches to control protein function with temporal specificity in behaving animals.
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