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Fayed MR, Ghandour K, Inokuchi K. Sleep and quiet wakefulness signify an idling brain hub for creative insights. Philos Trans R Soc Lond B Biol Sci 2024; 379:20230226. [PMID: 38853559 DOI: 10.1098/rstb.2023.0226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Accepted: 04/09/2024] [Indexed: 06/11/2024] Open
Abstract
Long-term potentiation of synaptic strength is a fundamental aspect of learning and memory. Memories are believed to be stored within specific populations of neurons known as engram cells, which are subsequently reactivated during sleep, facilitating the consolidation of stored information. However, sleep and offline reactivations are associated not only with past experiences but also with anticipation of future events. During periods of offline reactivation, which occur during sleep and quiet wakefulness, the brain exhibits a capability to form novel connections. This process links various past experiences, often leading to the emergence of qualitatively new information that was not initially available. Brain activity during sleep and quiet wakefulness is referred to as the 'idling brain'. Idling brain activity is believed to play a pivotal role in abstracting essential information, comprehending underlying rules, generating creative ideas and fostering insightful thoughts. In this review, we will explore the current state of research and future directions in understanding how sleep and idling brain activity are interconnected with various cognitive functions, especially creative insights. These insights have profound implications for our daily lives, impacting our ability to process information, make decisions and navigate complex situations effectively. This article is part of a discussion meeting issue 'Long-term potentiation: 50 years on'.
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Affiliation(s)
- Mostafa R Fayed
- Research Centre for Idling Brain Science, University of Toyama , Toyama 930-0194, Japan
- Department of Biochemistry, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama , Toyama 930-0194, Japan
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Kafrelsheikh University , Kafrelsheikh 33516, Egypt
| | - Khaled Ghandour
- Research Centre for Idling Brain Science, University of Toyama , Toyama 930-0194, Japan
- Department of Biochemistry, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama , Toyama 930-0194, Japan
- Department of Biochemistry, Faculty of Pharmacy, Cairo University , Cairo 11562, Egypt
| | - Kaoru Inokuchi
- Research Centre for Idling Brain Science, University of Toyama , Toyama 930-0194, Japan
- Department of Biochemistry, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama , Toyama 930-0194, Japan
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Liu Y, Ye S, Li XN, Li WG. Memory Trace for Fear Extinction: Fragile yet Reinforceable. Neurosci Bull 2024; 40:777-794. [PMID: 37812300 PMCID: PMC11178705 DOI: 10.1007/s12264-023-01129-3] [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: 04/02/2023] [Accepted: 06/08/2023] [Indexed: 10/10/2023] Open
Abstract
Fear extinction is a biological process in which learned fear behavior diminishes without anticipated reinforcement, allowing the organism to re-adapt to ever-changing situations. Based on the behavioral hypothesis that extinction is new learning and forms an extinction memory, this new memory is more readily forgettable than the original fear memory. The brain's cellular and synaptic traces underpinning this inherently fragile yet reinforceable extinction memory remain unclear. Intriguing questions are about the whereabouts of the engram neurons that emerged during extinction learning and how they constitute a dynamically evolving functional construct that works in concert to store and express the extinction memory. In this review, we discuss recent advances in the engram circuits and their neural connectivity plasticity for fear extinction, aiming to establish a conceptual framework for understanding the dynamic competition between fear and extinction memories in adaptive control of conditioned fear responses.
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Affiliation(s)
- Ying Liu
- Department of Rehabilitation Medicine, State Key Laboratory of Medical Neurobiology and Ministry of Education Frontiers Center for Brain Science, Huashan Hospital, Institute for Translational Brain Research, Fudan University, Shanghai, 200032, China
| | - Shuai Ye
- Department of Rehabilitation Medicine, State Key Laboratory of Medical Neurobiology and Ministry of Education Frontiers Center for Brain Science, Huashan Hospital, Institute for Translational Brain Research, Fudan University, Shanghai, 200032, China
| | - Xin-Ni Li
- Department of Rehabilitation Medicine, State Key Laboratory of Medical Neurobiology and Ministry of Education Frontiers Center for Brain Science, Huashan Hospital, Institute for Translational Brain Research, Fudan University, Shanghai, 200032, China
| | - Wei-Guang Li
- Department of Rehabilitation Medicine, State Key Laboratory of Medical Neurobiology and Ministry of Education Frontiers Center for Brain Science, Huashan Hospital, Institute for Translational Brain Research, Fudan University, Shanghai, 200032, China.
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Santos TB, de Oliveira Coelho CA, Kramer-Soares JC, Frankland PW, Oliveira MGM. Reactivation of encoding ensembles in the prelimbic cortex supports temporal associations. Neuropsychopharmacology 2024:10.1038/s41386-024-01825-2. [PMID: 38454052 DOI: 10.1038/s41386-024-01825-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 01/14/2024] [Accepted: 02/05/2024] [Indexed: 03/09/2024]
Abstract
Fear conditioning is encoded by strengthening synaptic connections between the neurons activated by a conditioned stimulus (CS) and those activated by an unconditioned stimulus (US), forming a memory engram, which is reactivated during memory retrieval. In temporal associations, activity within the prelimbic cortex (PL) plays a role in sustaining a short-term, transient memory of the CS, which is associated with the US after a temporal gap. However, it is unknown whether the PL has only a temporary role, transiently representing the CS, or is part of the neuronal ensembles that support the retrieval, i.e., whether PL neurons support both transient, short-term memories and stable, long-term memories. We investigated neuronal ensembles underlying temporal associations using fear conditioning with a 5-s interval between the CS and US (CFC-5s). Controls were trained in contextual fear conditioning (CFC), in which the CS-US overlaps. We used Robust Activity Marking (RAM) to selectively manipulate PL neurons activated by CFC-5s learning and Targeted Recombination in Active Populations (TRAP2) mice to label neurons activated by CFC-5s learning and reactivated by memory retrieval in the amygdala, medial prefrontal cortex, hippocampus, perirhinal cortices (PER) and subiculum. We also computed their co-reactivation to generate correlation-based networks. The optogenetic reactivation or silencing of PL encoding ensembles either promoted or impaired the retrieval of CFC-5s but not CFC. CFC-5s retrieval reactivated encoding ensembles in the PL, PER, and basolateral amygdala. The engram network of CFC-5s had higher amygdala and PER centralities and interconnectivity. The same PL neurons support learning and stable associative memories.
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Affiliation(s)
- Thays Brenner Santos
- Departamento de Psicobiologia, Universidade Federal de São Paulo - UNIFESP, São Paulo, 04023-062, Brazil.
| | | | - Juliana Carlota Kramer-Soares
- Departamento de Psicobiologia, Universidade Federal de São Paulo - UNIFESP, São Paulo, 04023-062, Brazil
- Universidade Cruzeiro do Sul - UNICSUL, São Paulo, 08060-070, Brazil
| | - Paul W Frankland
- Neuroscience and Mental Health, Hospital for Sick Children, Toronto, ON, M5G 0A4, Canada
- Department of Physiology, University of Toronto, Toronto, ON, M5G 1X8, Canada
- Department of Psychology, University of Toronto, Toronto, ON, M5G 1X8, Canada
- Institute of Medical Sciences, University of Toronto, Toronto, ON, M5G 1X8, Canada
- Child & Brain Development Program, Canadian Institute for Advanced Research, Toronto, ON, M5G 1M1, Canada
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Vingan I, Phatarpekar S, Tung VSK, Hernández AI, Evgrafov OV, Alarcon JM. Spatially Resolved Transcriptomic Signatures of Hippocampal Subregions and Arc-Expressing Ensembles in Active Place Avoidance Memory. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.12.30.573225. [PMID: 38260257 PMCID: PMC10802250 DOI: 10.1101/2023.12.30.573225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
The rodent hippocampus is a spatially organized neuronal network that supports the formation of spatial and episodic memories. We conducted bulk RNA sequencing and spatial transcriptomics experiments to measure gene expression changes in the dorsal hippocampus following the recall of active place avoidance (APA) memory. Through bulk RNA sequencing, we examined the gene expression changes following memory recall across the functionally distinct subregions of the dorsal hippocampus. We found that recall induced differentially expressed genes (DEGs) in the CA1 and CA3 hippocampal subregions were enriched with genes involved in synaptic transmission and synaptic plasticity, while DEGs in the dentate gyrus (DG) were enriched with genes involved in energy balance and ribosomal function. Through spatial transcriptomics, we examined gene expression changes following memory recall across an array of spots encompassing putative memory-associated neuronal ensembles marked by the expression of the IEGs Arc, Egr1, and c-Jun. Within samples from both trained and untrained mice, the subpopulations of spatial transcriptomic spots marked by these IEGs were transcriptomically and spatially distinct from one another. DEGs detected between Arc+ and Arc- spots exclusively in the trained mouse were enriched in several memory-related gene ontology terms, including "regulation of synaptic plasticity" and "memory." Our results suggest that APA memory recall is supported by regionalized transcriptomic profiles separating the CA1 and CA3 from the DG, transcriptionally and spatially distinct IEG expressing spatial transcriptomic spots, and biological processes related to synaptic plasticity as a defining the difference between Arc+ and Arc- spatial transcriptomic spots.
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Affiliation(s)
- Isaac Vingan
- School of Graduates Studies, Program in Neural and Behavioral Sciences, State University of New York, Downstate Health Sciences University, Brooklyn, NY, USA
| | - Shwetha Phatarpekar
- Institute of Genomics in Health, State University of New York, Downstate Health Sciences University, Brooklyn, NY, USA
| | - Victoria Sook Keng Tung
- School of Graduates Studies, Program in Molecular and Cell Biology, State University of New York, Downstate Health Sciences University, Brooklyn, NY, USA
| | - A Iván Hernández
- School of Graduates Studies, Program in Neural and Behavioral Sciences, State University of New York, Downstate Health Sciences University, Brooklyn, NY, USA
- Department of Pathology, State University of New York, Downstate Health Sciences University, Brooklyn, NY, USA
- The Robert F. Furchgott Center for Neural & Behavioral Science, State University of New York, Downstate Health Sciences University, Brooklyn, NY, USA
| | - Oleg V Evgrafov
- Institute of Genomics in Health, State University of New York, Downstate Health Sciences University, Brooklyn, NY, USA
- School of Graduates Studies, Program in Molecular and Cell Biology, State University of New York, Downstate Health Sciences University, Brooklyn, NY, USA
- Department of Cell Biology, State University of New York, Downstate Health Sciences University, Brooklyn, NY, USA
- Department of Genetics, Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ, USA
| | - Juan Marcos Alarcon
- School of Graduates Studies, Program in Neural and Behavioral Sciences, State University of New York, Downstate Health Sciences University, Brooklyn, NY, USA
- Department of Pathology, State University of New York, Downstate Health Sciences University, Brooklyn, NY, USA
- The Robert F. Furchgott Center for Neural & Behavioral Science, State University of New York, Downstate Health Sciences University, Brooklyn, NY, USA
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Wang CM, Wu CY, Lin CE, Hsu MC, Lin JC, Huang CC, Lien TY, Lin HK, Chang TW, Chiang HC. Forgotten memory storage and retrieval in Drosophila. Nat Commun 2023; 14:7153. [PMID: 37935667 PMCID: PMC10630420 DOI: 10.1038/s41467-023-42753-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 10/20/2023] [Indexed: 11/09/2023] Open
Abstract
Inaccessibility of stored memory in ensemble cells through the forgetting process causes animals to be unable to respond to natural recalling cues. While accumulating evidence has demonstrated that reactivating memory-stored cells can switch cells from an inaccessible state to an accessible form and lead to recall of previously learned information, the underlying cellular and molecular mechanisms remain elusive. The current study used Drosophila as a model to demonstrate that the memory of one-trial aversive olfactory conditioning, although inaccessible within a few hours after learning, is stored in KCαβ and retrievable after mild retraining. One-trial aversive conditioning triggers protein synthesis to form a long-lasting cellular memory trace, approximately 20 days, via creb in KCαβ, and a transient cellular memory trace, approximately one day, via orb in MBON-α3. PPL1-α3 negatively regulates forgotten one-trial conditioning memory retrieval. The current study demonstrated that KCαβ, PPL1-α3, and MBON-α3 collaboratively regulate the formation of forgotten one-cycle aversive conditioning memory formation and retrieval.
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Affiliation(s)
- Chih-Ming Wang
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan, ROC
- Brain Research Center, National Tsing Hua University, Hsinchu, Taiwan, ROC
| | - Chun-Yuan Wu
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan, ROC
| | - Chen-En Lin
- Department of Medicine, National Cheng-Kung University, Tainan, Taiwan, ROC
| | - Ming-Chi Hsu
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan, ROC
- Brain Research Center, National Tsing Hua University, Hsinchu, Taiwan, ROC
| | - Jing-Chun Lin
- Department of Medicine, National Cheng-Kung University, Tainan, Taiwan, ROC
| | - Chuan-Chin Huang
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan, ROC
- Brain Research Center, National Tsing Hua University, Hsinchu, Taiwan, ROC
| | - Ting-Yu Lien
- Department of Pharmacology, College of Medicine, National Cheng-Kung University, Tainan, Taiwan, ROC
| | - Hsin-Kai Lin
- Department of Medicine, National Cheng-Kung University, Tainan, Taiwan, ROC
| | - Ting-Wei Chang
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan, ROC
- Brain Research Center, National Tsing Hua University, Hsinchu, Taiwan, ROC
| | - Hsueh-Cheng Chiang
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan, ROC.
- Department of Pharmacology, College of Medicine, National Cheng-Kung University, Tainan, Taiwan, ROC.
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Kenna M, Marek R, Sah P. Insights into the encoding of memories through the circuitry of fear. Curr Opin Neurobiol 2023; 80:102712. [PMID: 37003106 DOI: 10.1016/j.conb.2023.102712] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 02/27/2023] [Accepted: 02/28/2023] [Indexed: 04/03/2023]
Abstract
Associative learning induces physical changes to a network of cells, known as the memory engram. Fear is widely used as a model to understand the circuit motifs that underpin associative memories. Recent advances suggest that the distinct circuitry engaged by different conditioned stimuli (e.g. tone vs. context) can provide insights into what information is being encoded in the fear engram. Moreover, as the fear memory matures, the circuitry engaged indicates how information is remodelled after learning and hints at potential mechanisms for consolidation. Finally, we propose that the consolidation of fear memories involves plasticity of engram cells through coordinated activity between brain regions, and the inherent characteristics of the circuitry may mediate this process.
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Affiliation(s)
- Matthew Kenna
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Roger Marek
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Pankaj Sah
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD 4072, Australia.
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Kobayashi KS, Matsuo N. Persistent representation of the environment in the hippocampus. Cell Rep 2023; 42:111989. [PMID: 36640328 DOI: 10.1016/j.celrep.2022.111989] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 11/23/2022] [Accepted: 12/23/2022] [Indexed: 01/13/2023] Open
Abstract
In the hippocampus, environmental changes elicit rearrangement of active neuronal ensembles or remapping of place cells. However, it remains elusive how the brain ensures a consistent representation of a certain environment itself despite salient events occurring there. Here, we longitudinally tracked calcium dynamics of dorsal hippocampal CA1 neurons in mice subjected to contextual fear conditioning and extinction training. Overall population activities were significantly changed by fear conditioning and were responsive to footshocks and freezing. However, a small subset of neurons, termed environment cells, were consistently active in a specific environment irrespective of experiences. A decoder modeling study showed that these cells, but not place cells, were able to predict the environment to which the mouse was exposed. Environment cells might underlie the constancy of cognition for distinct environments across time and events. Additionally, our study highlights the functional heterogeneity of cells in the hippocampus.
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Affiliation(s)
- Kyogo S Kobayashi
- Department of Biology, Faculty of Science, Kyushu University, Fukuoka 819-0395, Japan.
| | - Naoki Matsuo
- Department of Biology, Faculty of Science, Kyushu University, Fukuoka 819-0395, Japan.
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Ikeda Y, Taniguchi K, Yoshikawa S, Sawamura H, Tsuji A, Matsuda S. A budding concept with certain microbiota, anti-proliferative family proteins, and engram theory for the innovative treatment of colon cancer. EXPLORATION OF MEDICINE 2022. [DOI: 10.37349/emed.2022.00108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Inflammatory bowel disease (IBD) is a multifactorial chronic disease. Patients with IBD have an increased risk of developing colorectal cancer which has become a major health concern. IBD might exert a role of engrams for making the condition of specific inflammation in the gut. Dysregulation of immune cells induced by the command of engrams might be crucial in the pathogenesis of damages in gut epithelium. The anti-proliferative (APRO) family of anti-proliferative proteins characterized by immediate early responsive gene-products that might be involved in the machinery of the carcinogenesis in IBD. Herein, it is suggested that some probiotics with specific bacteria could prevent the development and/or progression of the IBD related tumors. In addition, consideration regarding the application of studying APRO family proteins for the comprehension of IBD related tumors has been presented. It is hypothesized that overexpression of Tob1, a member of APRO family proteins, in the epithelium of IBD could suppress the function of adjacent cytotoxic immune cells possibly via the paracrine signaling.
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Affiliation(s)
- Yuka Ikeda
- Department of Food Science and Nutrition, Nara Women’s University, Kita-Uoya Nishimachi, Nara 630-8506, Japan
| | - Kurumi Taniguchi
- Department of Food Science and Nutrition, Nara Women’s University, Kita-Uoya Nishimachi, Nara 630-8506, Japan
| | - Sayuri Yoshikawa
- Department of Food Science and Nutrition, Nara Women’s University, Kita-Uoya Nishimachi, Nara 630-8506, Japan
| | - Haruka Sawamura
- Department of Food Science and Nutrition, Nara Women’s University, Kita-Uoya Nishimachi, Nara 630-8506, Japan
| | - Ai Tsuji
- Department of Food Science and Nutrition, Nara Women’s University, Kita-Uoya Nishimachi, Nara 630-8506, Japan
| | - Satoru Matsuda
- Department of Food Science and Nutrition, Nara Women’s University, Kita-Uoya Nishimachi, Nara 630-8506, Japan
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