1
|
van Beest EH, Bimbard C, Fabre JMJ, Dodgson SW, Takács F, Coen P, Lebedeva A, Harris KD, Carandini M. Tracking neurons across days with high-density probes. Nat Methods 2024:10.1038/s41592-024-02440-1. [PMID: 39333269 DOI: 10.1038/s41592-024-02440-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Accepted: 09/03/2024] [Indexed: 09/29/2024]
Abstract
Neural activity spans multiple time scales, from milliseconds to months. Its evolution can be recorded with chronic high-density arrays such as Neuropixels probes, which can measure each spike at tens of sites and record hundreds of neurons. These probes produce vast amounts of data that require different approaches for tracking neurons across recordings. Here, to meet this need, we developed UnitMatch, a pipeline that operates after spike sorting, based only on each unit's average spike waveform. We tested UnitMatch in Neuropixels recordings from the mouse brain, where it tracked neurons across weeks. Across the brain, neurons had distinctive inter-spike interval distributions. Their correlations with other neurons remained stable over weeks. In the visual cortex, the neurons' selectivity for visual stimuli remained similarly stable. In the striatum, however, neuronal responses changed across days during learning of a task. UnitMatch is thus a promising tool to reveal both invariance and plasticity in neural activity across days.
Collapse
Affiliation(s)
- Enny H van Beest
- UCL Institute of Ophthalmology, University College London, London, UK.
| | - Célian Bimbard
- UCL Institute of Ophthalmology, University College London, London, UK.
| | - Julie M J Fabre
- UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Sam W Dodgson
- UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Flóra Takács
- Sainsbury Wellcome Centre, University College London, London, UK
| | - Philip Coen
- UCL Institute of Ophthalmology, University College London, London, UK
| | - Anna Lebedeva
- Sainsbury Wellcome Centre, University College London, London, UK
| | - Kenneth D Harris
- UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Matteo Carandini
- UCL Institute of Ophthalmology, University College London, London, UK
| |
Collapse
|
2
|
Miranda M, Silva A, Morici JF, Coletti MA, Belluscio M, Bekinschtein P. Retrieval of contextual memory can be predicted by CA3 remapping and is differentially influenced by NMDAR activity in rat hippocampus subregions. PLoS Biol 2024; 22:e3002706. [PMID: 38950066 PMCID: PMC11244845 DOI: 10.1371/journal.pbio.3002706] [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: 10/05/2023] [Revised: 07/12/2024] [Accepted: 06/12/2024] [Indexed: 07/03/2024] Open
Abstract
Episodic memory is essential to navigate in a changing environment by recalling past events, creating new memories, and updating stored information from experience. Although the mechanisms for acquisition and consolidation have been profoundly studied, much less is known about memory retrieval. Hippocampal spatial representations are key for retrieval of contextually guided episodic memories. Indeed, hippocampal place cells exhibit stable location-specific activity which is thought to support contextual memory, but can also undergo remapping in response to environmental changes. It is unclear if remapping is directly related to the expression of different episodic memories. Here, using an incidental memory recognition task in rats, we showed that retrieval of a contextually guided memory is reflected by the levels of CA3 remapping, demonstrating a clear link between external cues, hippocampal remapping, and episodic memory retrieval that guides behavior. Furthermore, we describe NMDARs as key players in regulating the balance between retrieval and memory differentiation processes by controlling the reactivation of specific memory traces. While an increase in CA3 NMDAR activity boosts memory retrieval, dentate gyrus NMDAR activity enhances memory differentiation. Our results contribute to understanding how the hippocampal circuit sustains a flexible balance between memory formation and retrieval depending on the environmental cues and the internal representations of the individual. They also provide new insights into the molecular mechanisms underlying the contributions of hippocampal subregions to generate this balance.
Collapse
Affiliation(s)
- Magdalena Miranda
- Laboratorio de Memoria y Cognición Molecular, Instituto de Neurociencia Cognitiva y Traslacional, CONICET-Fundación INECO-Universidad Favaloro, Ciudad Autónoma de Buenos Aires, Buenos Aires, Argentina
| | - Azul Silva
- Laboratorio Bases neuronales del comportamiento, Departamento de Ciencias Fisiológicas, Facultad de Ciencias Médicas, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Buenos Aires, Argentina
- CONICET—Universidad de Buenos Aires, Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO Houssay), Ciudad Autónoma de Buenos Aires, Buenos Aires, Argentina
| | - Juan Facundo Morici
- Laboratorio de Memoria y Cognición Molecular, Instituto de Neurociencia Cognitiva y Traslacional, CONICET-Fundación INECO-Universidad Favaloro, Ciudad Autónoma de Buenos Aires, Buenos Aires, Argentina
| | - Marcos Antonio Coletti
- Laboratorio Bases neuronales del comportamiento, Departamento de Ciencias Fisiológicas, Facultad de Ciencias Médicas, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Buenos Aires, Argentina
- CONICET—Universidad de Buenos Aires, Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO Houssay), Ciudad Autónoma de Buenos Aires, Buenos Aires, Argentina
| | - Mariano Belluscio
- Laboratorio Bases neuronales del comportamiento, Departamento de Ciencias Fisiológicas, Facultad de Ciencias Médicas, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Buenos Aires, Argentina
- CONICET—Universidad de Buenos Aires, Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO Houssay), Ciudad Autónoma de Buenos Aires, Buenos Aires, Argentina
| | - Pedro Bekinschtein
- Laboratorio de Memoria y Cognición Molecular, Instituto de Neurociencia Cognitiva y Traslacional, CONICET-Fundación INECO-Universidad Favaloro, Ciudad Autónoma de Buenos Aires, Buenos Aires, Argentina
| |
Collapse
|
3
|
Fenton AA. Remapping revisited: how the hippocampus represents different spaces. Nat Rev Neurosci 2024; 25:428-448. [PMID: 38714834 DOI: 10.1038/s41583-024-00817-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/04/2024] [Indexed: 05/25/2024]
Abstract
The representation of distinct spaces by hippocampal place cells has been linked to changes in their place fields (the locations in the environment where the place cells discharge strongly), a phenomenon that has been termed 'remapping'. Remapping has been assumed to be accompanied by the reorganization of subsecond cofiring relationships among the place cells, potentially maximizing hippocampal information coding capacity. However, several observations challenge this standard view. For example, place cells exhibit mixed selectivity, encode non-positional variables, can have multiple place fields and exhibit unreliable discharge in fixed environments. Furthermore, recent evidence suggests that, when measured at subsecond timescales, the moment-to-moment cofiring of a pair of cells in one environment is remarkably similar in another environment, despite remapping. Here, I propose that remapping is a misnomer for the changes in place fields across environments and suggest instead that internally organized manifold representations of hippocampal activity are actively registered to different environments to enable navigation, promote memory and organize knowledge.
Collapse
Affiliation(s)
- André A Fenton
- Center for Neural Science, New York University, New York, NY, USA.
- Neuroscience Institute at the NYU Langone Medical Center, New York, NY, USA.
| |
Collapse
|
4
|
Ventura S, Duncan S, Ainge JA. Increased flexibility of CA3 memory representations following environmental enrichment. Curr Biol 2024; 34:2011-2019.e7. [PMID: 38636511 DOI: 10.1016/j.cub.2024.03.054] [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: 11/17/2023] [Revised: 02/16/2024] [Accepted: 03/25/2024] [Indexed: 04/20/2024]
Abstract
Environmental enrichment (EE) improves memory, particularly the ability to discriminate similar past experiences.1,2,3,4,5,6 The hippocampus supports this ability via pattern separation, the encoding of similar events using dissimilar memory representations.7 This is carried out in the dentate gyrus (DG) and CA3 subfields.8,9,10,11,12 Upregulation of adult neurogenesis in the DG improves memory through enhanced pattern separation.1,2,3,4,5,6,11,13,14,15,16 Adult-born granule cells (abGCs) in DG are suggested to contribute to pattern separation by driving inhibition in regions such as CA3,13,14,15,16,17,18 leading to sparser, nonoverlapping representations of similar events (although a role for abGCs in driving excitation in the hippocampus has also been reported16). Place cells in the hippocampus contribute to pattern separation by remapping to spatial and contextual alterations to the environment.19,20,21,22,23,24,25,26,27 How spatial responses in CA3 are affected by EE and input from increased numbers of abGCs in DG is, however, unknown. Here, we investigate the neural mechanisms facilitating improved memory following EE using associative recognition memory tasks that model the automatic and integrative nature of episodic memory. We find that EE-dependent improvements in difficult discriminations are related to increased neurogenesis and sparser memory representations across the hippocampus. Additionally, we report for the first time that EE changes how CA3 place cells discriminate similar contexts. CA3 place cells of enriched rats show greater spatial tuning, increased firing rates, and enhanced remapping to contextual changes. These findings point to more precise and flexible CA3 memory representations in enriched rats, which provides a putative mechanism for EE-dependent improvements in fine memory discrimination.
Collapse
Affiliation(s)
- Silvia Ventura
- School of Psychology & Neuroscience, University of St. Andrews, St. Mary's Quad, South Street, St. Andrews, Fife, Scotland KY16 9JP, UK
| | - Stephen Duncan
- School of Psychology & Neuroscience, University of St. Andrews, St. Mary's Quad, South Street, St. Andrews, Fife, Scotland KY16 9JP, UK; School of Psychological & Brain Sciences, Indiana University, 1101 E 10th Street, Bloomington, IN 47405, USA
| | - James A Ainge
- School of Psychology & Neuroscience, University of St. Andrews, St. Mary's Quad, South Street, St. Andrews, Fife, Scotland KY16 9JP, UK.
| |
Collapse
|
5
|
Malone TJ, Tien NW, Ma Y, Cui L, Lyu S, Wang G, Nguyen D, Zhang K, Myroshnychenko MV, Tyan J, Gordon JA, Kupferschmidt DA, Gu Y. A consistent map in the medial entorhinal cortex supports spatial memory. Nat Commun 2024; 15:1457. [PMID: 38368457 PMCID: PMC10874432 DOI: 10.1038/s41467-024-45853-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 02/05/2024] [Indexed: 02/19/2024] Open
Abstract
The medial entorhinal cortex (MEC) is hypothesized to function as a cognitive map for memory-guided navigation. How this map develops during learning and influences memory remains unclear. By imaging MEC calcium dynamics while mice successfully learned a novel virtual environment over ten days, we discovered that the dynamics gradually became more spatially consistent and then stabilized. Additionally, grid cells in the MEC not only exhibited improved spatial tuning consistency, but also maintained stable phase relationships, suggesting a network mechanism involving synaptic plasticity and rigid recurrent connectivity to shape grid cell activity during learning. Increased c-Fos expression in the MEC in novel environments further supports the induction of synaptic plasticity. Unsuccessful learning lacked these activity features, indicating that a consistent map is specific for effective spatial memory. Finally, optogenetically disrupting spatial consistency of the map impaired memory-guided navigation in a well-learned environment. Thus, we demonstrate that the establishment of a spatially consistent MEC map across learning both correlates with, and is necessary for, successful spatial memory.
Collapse
Affiliation(s)
- Taylor J Malone
- Spatial Navigation and Memory Unit, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Nai-Wen Tien
- Spatial Navigation and Memory Unit, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA
- Washington University School of Medicine in St. Louis, St. Louis, MO, USA
| | - Yan Ma
- Spatial Navigation and Memory Unit, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Lian Cui
- Spatial Navigation and Memory Unit, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Shangru Lyu
- Spatial Navigation and Memory Unit, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Garret Wang
- Spatial Navigation and Memory Unit, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Duc Nguyen
- Spatial Navigation and Memory Unit, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA
- Center of Neural Science, New York University, New York, NY, USA
| | - Kai Zhang
- Spatial Navigation and Memory Unit, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA
- Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China
| | - Maxym V Myroshnychenko
- Integrative Neuroscience Section, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Jean Tyan
- Spatial Navigation and Memory Unit, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Joshua A Gordon
- Integrative Neuroscience Section, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, 20892, USA
- Office of the Director, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, 20892, USA
| | - David A Kupferschmidt
- Integrative Neuroscience Section, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Yi Gu
- Spatial Navigation and Memory Unit, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA.
| |
Collapse
|
6
|
Aoun A, Shetler O, Raghuraman R, Rodriguez GA, Hussaini SA. Beyond correlation: optimal transport metrics for characterizing representational stability and remapping in neurons encoding spatial memory. Front Cell Neurosci 2024; 17:1273283. [PMID: 38303974 PMCID: PMC10831886 DOI: 10.3389/fncel.2023.1273283] [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: 08/05/2023] [Accepted: 12/05/2023] [Indexed: 02/03/2024] Open
Abstract
Introduction Spatial representations in the entorhinal cortex (EC) and hippocampus (HPC) are fundamental to cognitive functions like navigation and memory. These representations, embodied in spatial field maps, dynamically remap in response to environmental changes. However, current methods, such as Pearson's correlation coefficient, struggle to capture the complexity of these remapping events, especially when fields do not overlap, or transformations are non-linear. This limitation hinders our understanding and quantification of remapping, a key aspect of spatial memory function. Methods We propose a family of metrics based on the Earth Mover's Distance (EMD) as a versatile framework for characterizing remapping. Results The EMD provides a granular, noise-resistant, and rate-robust description of remapping. This approach enables the identification of specific cell types and the characterization of remapping in various scenarios, including disease models. Furthermore, the EMD's properties can be manipulated to identify spatially tuned cell types and to explore remapping as it relates to alternate information forms such as spatiotemporal coding. Discussion We present a feasible, lightweight approach that complements traditional methods. Our findings underscore the potential of the EMD as a powerful tool for enhancing our understanding of remapping in the brain and its implications for spatial navigation, memory studies and beyond.
Collapse
Affiliation(s)
- Andrew Aoun
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, New York, NY, United States
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY, United States
| | - Oliver Shetler
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, New York, NY, United States
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY, United States
| | - Radha Raghuraman
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, New York, NY, United States
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY, United States
| | - Gustavo A. Rodriguez
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, New York, NY, United States
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY, United States
| | - S. Abid Hussaini
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, New York, NY, United States
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY, United States
| |
Collapse
|
7
|
Andreoli L, Tanaka KZ. What Can Hippocampal Engrams Tell Us About Encoding Spatial Navigation? ADVANCES IN NEUROBIOLOGY 2024; 38:195-214. [PMID: 39008017 DOI: 10.1007/978-3-031-62983-9_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/16/2024]
Abstract
The hippocampus is indispensable for episodic memories, but its particular role in the process is still unclear. This chapter briefly overviews past studies focusing on place cells and memory engrams, highlighting their potential roles in spatial navigation. Future work reconciling these two lines of studies would provide a comprehensive view of the specific contribution of the hippocampus and a better understanding of how memory engrams support memory.
Collapse
Affiliation(s)
- Lorena Andreoli
- Okinawa Institute of Science and Technology Graduate University (OIST), Memory Research Unit, Okinawa, Japan
| | - Kazumasa Z Tanaka
- Okinawa Institute of Science and Technology Graduate University (OIST), Memory Research Unit, Okinawa, Japan.
| |
Collapse
|
8
|
Plitt MH, Kaganovsky K, Südhof TC, Giocomo LM. Hippocampal place code plasticity in CA1 requires postsynaptic membrane fusion. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.20.567978. [PMID: 38045362 PMCID: PMC10690209 DOI: 10.1101/2023.11.20.567978] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
Rapid delivery of glutamate receptors to the postsynaptic membrane via vesicle fusion is a central component of synaptic plasticity. However, it is unknown how this process supports specific neural computations during behavior. To bridge this gap, we combined conditional genetic deletion of a component of the postsynaptic membrane fusion machinery, Syntaxin3 (Stx3), in hippocampal CA1 neurons of mice with population in vivo calcium imaging. This approach revealed that Stx3 is necessary for forming the neural dynamics that support novelty processing, spatial reward memory and offline memory consolidation. In contrast, CA1 Stx3 was dispensable for maintaining aspects of the neural code that exist presynaptic to CA1 such as representations of context and space. Thus, manipulating postsynaptic membrane fusion identified computations that specifically require synaptic restructuring via membrane trafficking in CA1 and distinguished them from neural representation that could be inherited from upstream brain regions or learned through other mechanisms.
Collapse
|
9
|
Aoun A, Shetler O, Raghuraman R, Rodriguez GA, Hussaini SA. Beyond Correlation: Optimal Transport Metrics For Characterizing Representational Stability and Remapping in Neurons Encoding Spatial Memory. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.11.548592. [PMID: 37503011 PMCID: PMC10369988 DOI: 10.1101/2023.07.11.548592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Spatial representations in the entorhinal cortex (EC) and hippocampus (HPC) are fundamental to cognitive functions like navigation and memory. These representations, embodied in spatial field maps, dynamically remap in response to environmental changes. However, current methods, such as Pearson's correlation coefficient, struggle to capture the complexity of these remapping events, especially when fields do not overlap, or transformations are non-linear. This limitation hinders our understanding and quantification of remapping, a key aspect of spatial memory function. To address this, we propose a family of metrics based on the Earth Mover's Distance (EMD) as a versatile framework for characterizing remapping. Applied to both normalized and unnormalized distributions, the EMD provides a granular, noise-resistant, and rate-robust description of remapping. This approach enables the identification of specific cell types and the characterization of remapping in various scenarios, including disease models. Furthermore, the EMD's properties can be manipulated to identify spatially tuned cell types and to explore remapping as it relates to alternate information forms such as spatiotemporal coding. By employing approximations of the EMD, we present a feasible, lightweight approach that complements traditional methods. Our findings underscore the potential of the EMD as a powerful tool for enhancing our understanding of remapping in the brain and its implications for spatial navigation, memory studies and beyond.
Collapse
Affiliation(s)
- Andrew Aoun
- Taub Institute for Research on Alzheimer’s Disease and the Aging Brain, Columbia University Medical Center, New York, NY 10032, USA
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY 10032, USA
- Co-first author
| | - Oliver Shetler
- Taub Institute for Research on Alzheimer’s Disease and the Aging Brain, Columbia University Medical Center, New York, NY 10032, USA
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY 10032, USA
- Co-first author
| | - Radha Raghuraman
- Taub Institute for Research on Alzheimer’s Disease and the Aging Brain, Columbia University Medical Center, New York, NY 10032, USA
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY 10032, USA
| | - Gustavo A. Rodriguez
- Taub Institute for Research on Alzheimer’s Disease and the Aging Brain, Columbia University Medical Center, New York, NY 10032, USA
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY 10032, USA
| | - S. Abid Hussaini
- Taub Institute for Research on Alzheimer’s Disease and the Aging Brain, Columbia University Medical Center, New York, NY 10032, USA
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY 10032, USA
| |
Collapse
|
10
|
Levy ERJ, Carrillo-Segura S, Park EH, Redman WT, Hurtado JR, Chung S, Fenton AA. A manifold neural population code for space in hippocampal coactivity dynamics independent of place fields. Cell Rep 2023; 42:113142. [PMID: 37742193 PMCID: PMC10842170 DOI: 10.1016/j.celrep.2023.113142] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 06/14/2023] [Accepted: 08/30/2023] [Indexed: 09/26/2023] Open
Abstract
Hippocampus place cell discharge is temporally unreliable across seconds and days, and place fields are multimodal, suggesting an "ensemble cofiring" spatial coding hypothesis with manifold dynamics that does not require reliable spatial tuning, in contrast to hypotheses based on place field (spatial tuning) stability. We imaged mouse CA1 (cornu ammonis 1) ensembles in two environments across three weeks to evaluate these coding hypotheses. While place fields "remap," being more distinct between than within environments, coactivity relationships generally change less. Decoding location and environment from 1-s ensemble location-specific activity is effective and improves with experience. Decoding environment from cell-pair coactivity relationships is also effective and improves with experience, even after removing place tuning. Discriminating environments from 1-s ensemble coactivity relies crucially on the cells with the most anti-coactive cell-pair relationships because activity is internally organized on a low-dimensional manifold of non-linear coactivity relationships that intermittently reregisters to environments according to the anti-cofiring subpopulation activity.
Collapse
Affiliation(s)
| | - Simón Carrillo-Segura
- Center for Neural Science, New York University, New York, NY 10003, USA; Graduate Program in Mechanical and Aerospace Engineering, Tandon School of Engineering, New York University, Brooklyn, NY 11201, USA
| | - Eun Hye Park
- Center for Neural Science, New York University, New York, NY 10003, USA
| | - William Thomas Redman
- Interdepartmental Graduate Program in Dynamical Neuroscience, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | | | - SueYeon Chung
- Center for Neural Science, New York University, New York, NY 10003, USA; Flatiron Institute Center for Computational Neuroscience, New York, NY 10010, USA
| | - André Antonio Fenton
- Center for Neural Science, New York University, New York, NY 10003, USA; Neuroscience Institute at the NYU Langone Medical Center, New York, NY 10016, USA.
| |
Collapse
|
11
|
Berndt M, Trusel M, Roberts TF, Pfeiffer BE, Volk LJ. Bidirectional synaptic changes in deep and superficial hippocampal neurons following in vivo activity. Neuron 2023; 111:2984-2994.e4. [PMID: 37689058 PMCID: PMC10958998 DOI: 10.1016/j.neuron.2023.08.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Revised: 07/06/2023] [Accepted: 08/15/2023] [Indexed: 09/11/2023]
Abstract
Neuronal activity during experience is thought to induce plastic changes within the hippocampal network that underlie memory formation, although the extent and details of such changes in vivo remain unclear. Here, we employed a temporally precise marker of neuronal activity, CaMPARI2, to label active CA1 hippocampal neurons in vivo, followed by immediate acute slice preparation and electrophysiological quantification of synaptic properties. Recently active neurons in the superficial sublayer of stratum pyramidale displayed larger post-synaptic responses at excitatory synapses from area CA3, with no change in pre-synaptic release probability. In contrast, in vivo activity correlated with weaker pre- and post-synaptic excitatory weights onto pyramidal cells in the deep sublayer. In vivo activity of deep and superficial neurons within sharp-wave/ripples was bidirectionally changed across experience, consistent with the observed changes in synaptic weights. These findings reveal novel, fundamental mechanisms through which the hippocampal network is modified by experience to store information.
Collapse
Affiliation(s)
- Marcus Berndt
- UT Southwestern Medical Center Neuroscience Graduate Program, Dallas, TX 75390, USA; UT Southwestern Medical Center Department of Neuroscience, Dallas, TX 75390, USA
| | - Massimo Trusel
- UT Southwestern Medical Center Department of Neuroscience, Dallas, TX 75390, USA
| | - Todd F Roberts
- UT Southwestern Medical Center Neuroscience Graduate Program, Dallas, TX 75390, USA; UT Southwestern Medical Center Department of Neuroscience, Dallas, TX 75390, USA; Peter O'Donnell Brain Institute, Dallas, TX 75390, USA
| | - Brad E Pfeiffer
- UT Southwestern Medical Center Neuroscience Graduate Program, Dallas, TX 75390, USA; UT Southwestern Medical Center Department of Neuroscience, Dallas, TX 75390, USA; Peter O'Donnell Brain Institute, Dallas, TX 75390, USA.
| | - Lenora J Volk
- UT Southwestern Medical Center Neuroscience Graduate Program, Dallas, TX 75390, USA; UT Southwestern Medical Center Department of Neuroscience, Dallas, TX 75390, USA; UT Southwestern Medical Center Department of Psychiatry, Dallas, TX 75390, USA; Peter O'Donnell Brain Institute, Dallas, TX 75390, USA.
| |
Collapse
|
12
|
Malone TJ, Tien NW, Ma Y, Cui L, Lyu S, Wang G, Nguyen D, Zhang K, Myroshnychenko MV, Tyan J, Gordon JA, Kupferschmidt DA, Gu Y. A consistent map in the medial entorhinal cortex supports spatial memory. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.30.560254. [PMID: 37986767 PMCID: PMC10659391 DOI: 10.1101/2023.09.30.560254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
The medial entorhinal cortex (MEC) is hypothesized to function as a cognitive map for memory-guided navigation. How this map develops during learning and influences memory remains unclear. By imaging MEC calcium dynamics while mice successfully learned a novel virtual environment over ten days, we discovered that the dynamics gradually became more spatially consistent and then stabilized. Additionally, grid cells in the MEC not only exhibited improved spatial tuning consistency, but also maintained stable phase relationships, suggesting a network mechanism involving synaptic plasticity and rigid recurrent connectivity to shape grid cell activity during learning. Increased c-Fos expression in the MEC in novel environments further supports the induction of synaptic plasticity. Unsuccessful learning lacked these activity features, indicating that a consistent map is specific for effective spatial memory. Finally, optogenetically disrupting spatial consistency of the map impaired memory-guided navigation in a well-learned environment. Thus, we demonstrate that the establishment of a spatially consistent MEC map across learning both correlates with, and is necessary for, successful spatial memory.
Collapse
Affiliation(s)
- Taylor J. Malone
- Spatial Navigation and Memory Unit, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
- These authors contributed equally to this work
| | - Nai-Wen Tien
- Spatial Navigation and Memory Unit, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
- Current address: Washington University School of Medicine in St. Louis, St. Louis, MO, USA
- These authors contributed equally to this work
| | - Yan Ma
- Spatial Navigation and Memory Unit, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
- These authors contributed equally to this work
| | - Lian Cui
- Spatial Navigation and Memory Unit, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Shangru Lyu
- Spatial Navigation and Memory Unit, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Garret Wang
- Spatial Navigation and Memory Unit, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Duc Nguyen
- Spatial Navigation and Memory Unit, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
- Current address: Center of Neural Science, New York University, New York, NY, USA
| | - Kai Zhang
- Spatial Navigation and Memory Unit, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
- Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China
| | - Maxym V. Myroshnychenko
- Integrative Neuroscience Section, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jean Tyan
- Spatial Navigation and Memory Unit, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Joshua A. Gordon
- Integrative Neuroscience Section, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA
- Office of the Director, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA
| | - David A. Kupferschmidt
- Integrative Neuroscience Section, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA
| | - Yi Gu
- Spatial Navigation and Memory Unit, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| |
Collapse
|
13
|
Nicoll RA, Schulman H. Synaptic memory and CaMKII. Physiol Rev 2023; 103:2877-2925. [PMID: 37290118 PMCID: PMC10642921 DOI: 10.1152/physrev.00034.2022] [Citation(s) in RCA: 22] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 04/26/2023] [Accepted: 04/30/2023] [Indexed: 06/10/2023] Open
Abstract
Ca2+/calmodulin-dependent protein kinase II (CaMKII) and long-term potentiation (LTP) were discovered within a decade of each other and have been inextricably intertwined ever since. However, like many marriages, it has had its up and downs. Based on the unique biochemical properties of CaMKII, it was proposed as a memory molecule before any physiological linkage was made to LTP. However, as reviewed here, the convincing linkage of CaMKII to synaptic physiology and behavior took many decades. New technologies were critical in this journey, including in vitro brain slices, mouse genetics, single-cell molecular genetics, pharmacological reagents, protein structure, and two-photon microscopy, as were new investigators attracted by the exciting challenge. This review tracks this journey and assesses the state of this marriage 40 years on. The collective literature impels us to propose a relatively simple model for synaptic memory involving the following steps that drive the process: 1) Ca2+ entry through N-methyl-d-aspartate (NMDA) receptors activates CaMKII. 2) CaMKII undergoes autophosphorylation resulting in constitutive, Ca2+-independent activity and exposure of a binding site for the NMDA receptor subunit GluN2B. 3) Active CaMKII translocates to the postsynaptic density (PSD) and binds to the cytoplasmic C-tail of GluN2B. 4) The CaMKII-GluN2B complex initiates a structural rearrangement of the PSD that may involve liquid-liquid phase separation. 5) This rearrangement involves the PSD-95 scaffolding protein, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs), and their transmembrane AMPAR-regulatory protein (TARP) auxiliary subunits, resulting in an accumulation of AMPARs in the PSD that underlies synaptic potentiation. 6) The stability of the modified PSD is maintained by the stability of the CaMKII-GluN2B complex. 7) By a process of subunit exchange or interholoenzyme phosphorylation CaMKII maintains synaptic potentiation in the face of CaMKII protein turnover. There are many other important proteins that participate in enlargement of the synaptic spine or modulation of the steps that drive and maintain the potentiation. In this review we critically discuss the data underlying each of the steps. As will become clear, some of these steps are more firmly grounded than others, and we provide suggestions as to how the evidence supporting these steps can be strengthened or, based on the new data, be replaced. Although the journey has been a long one, the prospect of having a detailed cellular and molecular understanding of learning and memory is at hand.
Collapse
Affiliation(s)
- Roger A Nicoll
- Department of Cellular and Molecular Pharmacology, University of California at San Francisco, San Francisco, California, United States
| | - Howard Schulman
- Department of Neurobiology, Stanford University School of Medicine, Stanford, California, United States
- Panorama Research Institute, Sunnyvale, California, United States
| |
Collapse
|
14
|
Kim EJ, Kim JJ. Neurocognitive effects of stress: a metaparadigm perspective. Mol Psychiatry 2023; 28:2750-2763. [PMID: 36759545 PMCID: PMC9909677 DOI: 10.1038/s41380-023-01986-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 01/26/2023] [Accepted: 01/27/2023] [Indexed: 02/11/2023]
Abstract
Stressful experiences, both physical and psychological, that are overwhelming (i.e., inescapable and unpredictable), can measurably affect subsequent neuronal properties and cognitive functioning of the hippocampus. At the cellular level, stress has been shown to alter hippocampal synaptic plasticity, spike and local field potential activity, dendritic morphology, neurogenesis, and neurodegeneration. At the behavioral level, stress has been found to impair learning and memory for declarative (or explicit) tasks that are based on cognition, such as verbal recall memory in humans and spatial memory in rodents, while facilitating those that are based on emotion, such as differential fear conditioning in humans and contextual fear conditioning in rodents. These vertically related alterations in the hippocampus, procedurally observed after subjects have undergone stress, are generally believed to be mediated by recurrently elevated circulating hypothalamic-pituitary-adrenal (HPA) axis effector hormones, glucocorticoids, directly acting on hippocampal neurons densely populated with corticosteroid receptors. The main purposes of this review are to (i) provide a synopsis of the neurocognitive effects of stress in a historical context that led to the contemporary HPA axis dogma of basic and translational stress research, (ii) critically reappraise the necessity and sufficiency of the glucocorticoid hypothesis of stress, and (iii) suggest an alternative metaparadigm approach to monitor and manipulate the progression of stress effects at the neural coding level. Real-time analyses can reveal neural activity markers of stress in the hippocampus that can be used to extrapolate neurocognitive effects across a range of stress paradigms (i.e., resolve scaling and dichotomous memory effects issues) and understand individual differences, thereby providing a novel neurophysiological scaffold for advancing future stress research.
Collapse
Affiliation(s)
- Eun Joo Kim
- Department of Psychology, University of Washington, Seattle, WA, 98195, USA
- School of Psychology, Korea University, Seoul, 02841, Republic of Korea
| | - Jeansok J Kim
- Department of Psychology, University of Washington, Seattle, WA, 98195, USA.
| |
Collapse
|
15
|
Xie B, Zhen Z, Guo O, Li H, Guo M, Zhen J. Progress on the hippocampal circuits and functions based on sharp wave ripples. Brain Res Bull 2023:110695. [PMID: 37353037 DOI: 10.1016/j.brainresbull.2023.110695] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 06/18/2023] [Accepted: 06/20/2023] [Indexed: 06/25/2023]
Abstract
Sharp wave ripples (SWRs) are high-frequency synchronization events generated by hippocampal neuronal circuits during various forms of learning and reactivated during memory consolidation and recall. There is mounting evidence that SWRs are essential for storing spatial and social memories in rodents and short-term episodic memories in humans. Sharp wave ripples originate mainly from the hippocampal CA3 and subiculum, and can be transmitted to modulate neuronal activity in cortical and subcortical regions for long-term memory consolidation and behavioral guidance. Different hippocampal subregions have distinct functions in learning and memory. For instance, the dorsal CA1 is critical for spatial navigation, episodic memory, and learning, while the ventral CA1 and dorsal CA2 may work cooperatively to store and consolidate social memories. Here, we summarize recent studies demonstrating that SWRs are essential for the consolidation of spatial, episodic, and social memories in various hippocampal-cortical pathways, and review evidence that SWR dysregulation contributes to cognitive impairments in neurodegenerative and neurodevelopmental diseases.
Collapse
Affiliation(s)
- Boxu Xie
- Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, China
| | - Zhihang Zhen
- Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, China
| | - Ouyang Guo
- Department of Biology, Boston University, Boston, MA, United States
| | - Heming Li
- Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, China
| | - Moran Guo
- Neurological Laboratory of Hebei Province, Shijiazhuang, China
| | - Junli Zhen
- Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, China; Neurological Laboratory of Hebei Province, Shijiazhuang, China.
| |
Collapse
|
16
|
Zhang H, Chen L, Johnston KG, Crapser J, Green KN, Ha NML, Tenner AJ, Holmes TC, Nitz DA, Xu X. Degenerate mapping of environmental location presages deficits in object-location encoding and memory in the 5xFAD mouse model for Alzheimer's disease. Neurobiol Dis 2023; 176:105939. [PMID: 36462718 PMCID: PMC10187684 DOI: 10.1016/j.nbd.2022.105939] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 11/08/2022] [Accepted: 11/30/2022] [Indexed: 12/03/2022] Open
Abstract
A key challenge in developing diagnosis and treatments for Alzheimer's disease (AD) is to detect abnormal network activity at as early a stage as possible. To date, behavioral and neurophysiological investigations in AD model mice have yet to conduct a longitudinal assessment of cellular pathology, memory deficits, and neurophysiological correlates of neuronal activity. We therefore examined the temporal relationships between pathology, neuronal activities and spatial representation of environments, as well as object location memory deficits across multiple stages of development in the 5xFAD mice model and compared these results to those observed in wild-type mice. We performed longitudinal in vivo calcium imaging with miniscope on hippocampal CA1 neurons in behaving mice. We find that 5xFAD mice show amyloid plaque accumulation, depressed neuronal calcium activity during immobile states, and degenerate and unreliable hippocampal neuron spatial tuning to environmental location at early stages by 4 months of age while their object location memory (OLM) is comparable to WT mice. By 8 months of age, 5xFAD mice show deficits of OLM, which are accompanied by progressive degradation of spatial encoding and, eventually, impaired CA1 neural tuning to object-location pairings. Furthermore, depressed neuronal activity and unreliable spatial encoding at early stage are correlated with impaired performance in OLM at 8-month-old. Our results indicate the close connection between impaired hippocampal tuning to object-location and the presence of OLM deficits. The results also highlight that depressed baseline firing rates in hippocampal neurons during immobile states and unreliable spatial representation precede object memory deficits and predict memory deficits at older age, suggesting potential early opportunities for AD detecting.
Collapse
Affiliation(s)
- Hai Zhang
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, CA 92697, United States of America
| | - Lujia Chen
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, CA 92697, United States of America; Department of Biomedical Engineering, University of California, Irvine, CA 92697, United States of America
| | - Kevin G Johnston
- Department of Mathematics, University of California, Irvine, CA 92697, United States of America
| | - Joshua Crapser
- Department of Neurobiology and Behavior, School of Biological Sciences, University of California, Irvine, CA 92697, United States of America
| | - Kim N Green
- Department of Neurobiology and Behavior, School of Biological Sciences, University of California, Irvine, CA 92697, United States of America; Center for Neural Circuit Mapping, University of California, Irvine, CA 92697, United States of America
| | - Nicole My-Linh Ha
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, CA 92697, United States of America
| | - Andrea J Tenner
- Department of Molecular Biology and Biochemistry, School of Biological Sciences, University of California, Irvine, CA 92697, United States of America
| | - Todd C Holmes
- Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA 92697, United States of America; Center for Neural Circuit Mapping, University of California, Irvine, CA 92697, United States of America
| | - Douglas A Nitz
- Department of Cognitive Science, University of California, San Diego, La Jolla, CA 92093, United States of America; Center for Neural Circuit Mapping, University of California, Irvine, CA 92697, United States of America.
| | - Xiangmin Xu
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, CA 92697, United States of America; Department of Biomedical Engineering, University of California, Irvine, CA 92697, United States of America; Center for Neural Circuit Mapping, University of California, Irvine, CA 92697, United States of America.
| |
Collapse
|
17
|
Asiminas A, Booker SA, Dando OR, Kozic Z, Arkell D, Inkpen FH, Sumera A, Akyel I, Kind PC, Wood ER. Experience-dependent changes in hippocampal spatial activity and hippocampal circuit function are disrupted in a rat model of Fragile X Syndrome. Mol Autism 2022; 13:49. [PMID: 36536454 PMCID: PMC9764562 DOI: 10.1186/s13229-022-00528-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 12/01/2022] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Fragile X syndrome (FXS) is a common single gene cause of intellectual disability and autism spectrum disorder. Cognitive inflexibility is one of the hallmarks of FXS with affected individuals showing extreme difficulty adapting to novel or complex situations. To explore the neural correlates of this cognitive inflexibility, we used a rat model of FXS (Fmr1-/y). METHODS We recorded from the CA1 in Fmr1-/y and WT littermates over six 10-min exploration sessions in a novel environment-three sessions per day (ITI 10 min). Our recordings yielded 288 and 246 putative pyramidal cells from 7 WT and 7 Fmr1-/y rats, respectively. RESULTS On the first day of exploration of a novel environment, the firing rate and spatial tuning of CA1 pyramidal neurons was similar between wild-type (WT) and Fmr1-/y rats. However, while CA1 pyramidal neurons from WT rats showed experience-dependent changes in firing and spatial tuning between the first and second day of exposure to the environment, these changes were decreased or absent in CA1 neurons of Fmr1-/y rats. These findings were consistent with increased excitability of Fmr1-/y CA1 neurons in ex vivo hippocampal slices, which correlated with reduced synaptic inputs from the medial entorhinal cortex. Lastly, activity patterns of CA1 pyramidal neurons were dis-coordinated with respect to hippocampal oscillatory activity in Fmr1-/y rats. LIMITATIONS It is still unclear how the observed circuit function abnormalities give rise to behavioural deficits in Fmr1-/y rats. Future experiments will focus on this connection as well as the contribution of other neuronal cell types in the hippocampal circuit pathophysiology associated with the loss of FMRP. It would also be interesting to see if hippocampal circuit deficits converge with those seen in other rodent models of intellectual disability. CONCLUSIONS In conclusion, we found that hippocampal place cells from Fmr1-/y rats show similar spatial firing properties as those from WT rats but do not show the same experience-dependent increase in spatial specificity or the experience-dependent changes in network coordination. Our findings offer support to a network-level origin of cognitive deficits in FXS.
Collapse
Affiliation(s)
- Antonis Asiminas
- grid.4305.20000 0004 1936 7988Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD UK ,grid.4305.20000 0004 1936 7988Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, EH8 9XD UK ,grid.4305.20000 0004 1936 7988Patrick Wild Centre, University of Edinburgh, Edinburgh, EH8 9XD UK ,grid.5254.60000 0001 0674 042XPresent Address: Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Sam A. Booker
- grid.4305.20000 0004 1936 7988Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD UK ,grid.4305.20000 0004 1936 7988Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, EH8 9XD UK ,grid.4305.20000 0004 1936 7988Patrick Wild Centre, University of Edinburgh, Edinburgh, EH8 9XD UK
| | - Owen R. Dando
- grid.4305.20000 0004 1936 7988Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD UK ,grid.4305.20000 0004 1936 7988Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, EH8 9XD UK ,grid.4305.20000 0004 1936 7988Patrick Wild Centre, University of Edinburgh, Edinburgh, EH8 9XD UK ,grid.4305.20000 0004 1936 7988UK Dementia Research Institute at the Edinburgh Medical School, University of Edinburgh, Edinburgh, EH8 9XD UK
| | - Zrinko Kozic
- grid.4305.20000 0004 1936 7988Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD UK ,grid.4305.20000 0004 1936 7988Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, EH8 9XD UK
| | - Daisy Arkell
- grid.4305.20000 0004 1936 7988Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD UK ,grid.4305.20000 0004 1936 7988Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, EH8 9XD UK ,grid.4305.20000 0004 1936 7988Patrick Wild Centre, University of Edinburgh, Edinburgh, EH8 9XD UK
| | - Felicity H. Inkpen
- grid.4305.20000 0004 1936 7988Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD UK ,grid.4305.20000 0004 1936 7988Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, EH8 9XD UK ,grid.4305.20000 0004 1936 7988Patrick Wild Centre, University of Edinburgh, Edinburgh, EH8 9XD UK
| | - Anna Sumera
- grid.4305.20000 0004 1936 7988Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD UK ,grid.4305.20000 0004 1936 7988Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, EH8 9XD UK ,grid.4305.20000 0004 1936 7988Patrick Wild Centre, University of Edinburgh, Edinburgh, EH8 9XD UK
| | - Irem Akyel
- grid.4305.20000 0004 1936 7988Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD UK ,grid.4305.20000 0004 1936 7988Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, EH8 9XD UK
| | - Peter C. Kind
- grid.4305.20000 0004 1936 7988Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD UK ,grid.4305.20000 0004 1936 7988Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, EH8 9XD UK ,grid.4305.20000 0004 1936 7988Patrick Wild Centre, University of Edinburgh, Edinburgh, EH8 9XD UK ,Centre for Brain Development and Repair, Bangalore, 560065 India
| | - Emma R. Wood
- grid.4305.20000 0004 1936 7988Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD UK ,grid.4305.20000 0004 1936 7988Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, EH8 9XD UK ,grid.4305.20000 0004 1936 7988Patrick Wild Centre, University of Edinburgh, Edinburgh, EH8 9XD UK ,Centre for Brain Development and Repair, Bangalore, 560065 India
| |
Collapse
|
18
|
Lee SM, Shin J, Lee I. Significance of visual scene-based learning in the hippocampal systems across mammalian species. Hippocampus 2022; 33:505-521. [PMID: 36458555 DOI: 10.1002/hipo.23483] [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: 09/05/2022] [Revised: 10/26/2022] [Accepted: 11/19/2022] [Indexed: 12/04/2022]
Abstract
The hippocampus and its associated cortical regions in the medial temporal lobe play essential roles when animals form a cognitive map and use it to achieve their goals. As the nature of map-making involves sampling different local views of the environment and putting them together in a spatially cohesive way, visual scenes are essential ingredients in the formative process of cognitive maps. Visual scenes also serve as important cues during information retrieval from the cognitive map. Research in humans has shown that there are regions in the brain that selectively process scenes and that the hippocampus is involved in scene-based memory tasks. The neurophysiological correlates of scene-based information processing in the hippocampus have been reported as "spatial view cells" in nonhuman primates. Like primates, it is widely accepted that rodents also use visual scenes in their background for spatial navigation and other kinds of problems. However, in rodents, it is not until recently that researchers examined the neural correlates of the hippocampus from the perspective of visual scene-based information processing. With the advent of virtual reality (VR) systems, it has been demonstrated that place cells in the hippocampus exhibit remarkably similar firing correlates in the VR environment compared with that of the real-world environment. Despite some limitations, the new trend of studying hippocampal functions in a visually controlled environment has the potential to allow investigation of the input-output relationships of network functions and experimental testing of traditional computational predictions more rigorously by providing well-defined visual stimuli. As scenes are essential for navigation and episodic memory in humans, further investigation of the rodents' hippocampal systems in scene-based tasks will provide a critical functional link across different mammalian species.
Collapse
Affiliation(s)
- Su-Min Lee
- Department of Brain and Cognitive Sciences, Seoul National University, Seoul, South Korea
| | - Jhoseph Shin
- Department of Brain and Cognitive Sciences, Seoul National University, Seoul, South Korea
| | - Inah Lee
- Department of Brain and Cognitive Sciences, Seoul National University, Seoul, South Korea
| |
Collapse
|
19
|
Ruzicka J, Dalecka M, Safrankova K, Peretti D, Jendelova P, Kwok JCF, Fawcett JW. Perineuronal nets affect memory and learning after synapse withdrawal. Transl Psychiatry 2022; 12:480. [PMID: 36379919 PMCID: PMC9666654 DOI: 10.1038/s41398-022-02226-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 09/08/2022] [Accepted: 10/19/2022] [Indexed: 11/16/2022] Open
Abstract
Perineuronal nets (PNNs) enwrap mature neurons, playing a role in the control of plasticity and synapse dynamics. PNNs have been shown to have effects on memory formation, retention and extinction in a variety of animal models. It has been proposed that the cavities in PNNs, which contain synapses, can act as a memory store and that they remain stable after events that cause synaptic withdrawal such as anoxia or hibernation. We examine this idea by monitoring place memory before and after synaptic withdrawal caused by acute hibernation-like state (HLS). Animals lacking hippocampal PNNs due to enzymatic digestion by chondroitinase ABC or knockout of the PNN component aggrecan were compared with wild type controls. HLS-induced synapse withdrawal caused a memory deficit, but not to the level of untreated naïve animals and not worsened by PNN attenuation. After HLS, only animals lacking PNNs showed memory restoration or relearning. Absence of PNNs affected the restoration of excitatory synapses on PNN-bearing neurons. The results support a role for hippocampal PNNs in learning, but not in long-term memory storage for correction of deficits.
Collapse
Affiliation(s)
- Jiri Ruzicka
- grid.424967.a0000 0004 0404 6946Institute of Experimental Medicine, CAS, Prague, Czech Republic
| | - Marketa Dalecka
- grid.418095.10000 0001 1015 3316Imaging Methods Core Facility, BIOCEV, CAS, Vestec, Czech Republic
| | - Kristyna Safrankova
- grid.424967.a0000 0004 0404 6946Institute of Experimental Medicine, CAS, Prague, Czech Republic
| | - Diego Peretti
- grid.5335.00000000121885934UK Dementia Research Institute and Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Pavla Jendelova
- grid.424967.a0000 0004 0404 6946Institute of Experimental Medicine, CAS, Prague, Czech Republic
| | - Jessica C. F. Kwok
- grid.424967.a0000 0004 0404 6946Institute of Experimental Medicine, CAS, Prague, Czech Republic ,grid.9909.90000 0004 1936 8403Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - James W. Fawcett
- grid.424967.a0000 0004 0404 6946Institute of Experimental Medicine, CAS, Prague, Czech Republic ,grid.5335.00000000121885934John van Geest Centre for Brain Repair, University of Cambridge, Cambridge, UK
| |
Collapse
|
20
|
Sikora J, Di Bisceglie Caballero S, Reiss D, Kieffer BL, Paoletti P, Jacob PY, Ouagazzal AM. Zn2+ inhibits spatial memory and hippocampal place cell representation through high-affinity binding to the NMDA receptor GluN2A subunit. iScience 2022; 25:105355. [DOI: 10.1016/j.isci.2022.105355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 08/11/2022] [Accepted: 10/11/2022] [Indexed: 10/31/2022] Open
|
21
|
Zhu M, Perkins MG, Lennertz R, Abdulzahir A, Pearce RA. Dose-dependent suppression of hippocampal contextual memory formation, place cells, and spatial engrams by the NMDAR antagonist (R)-CPP. Neuropharmacology 2022; 218:109215. [PMID: 35977628 PMCID: PMC9673467 DOI: 10.1016/j.neuropharm.2022.109215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 08/04/2022] [Accepted: 08/08/2022] [Indexed: 11/16/2022]
Abstract
We recently reported that the competitive NMDAR antagonist (R,S)-3-(2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid (CPP) does not suppress NMDAR-mediated field EPSPs (fEPSPNMDA) or long-term potentiation (LTP) in vitro at concentrations that block contextual conditioning in vivo. Here we tested one possible explanation for the mismatch - that the hippocampus is relatively resistant to CPP compared to other brain structures engaged in contextual fear conditioning. Using the context pre-exposure facilitation effect (CPFE) paradigm to separate the hippocampal and extra-hippocampal components of contextual learning, we found that the active enantiomer (R)-CPP suppressed the hippocampal component with an IC50 of 3.1 mg/kg, a dose that produces brain concentrations below those required to block fEPSPNMDA or LTP. Moreover, using in-vivo calcium imaging of place cells and spatial engrams to directly assess hippocampal spatial coding, we found that (R)-CPP dose-dependently reduced the development of place cells and interfered with the formation of stable spatial engrams when it was administered prior to exposing mice to a novel context. Both effects occurred at doses that interfered with freezing to context in CPFE experiments. We conclude that (R)-CPP blocks memory formation by interfering with hippocampal function, but that it does so by modulating NMDARs at sites that are not engaged in vitro in the same manner that they are in vivo - perhaps through interneuron circuits that do not contribute to fEPSPs and are not required to elicit LTP using standard induction protocols in vitro, but are essential for successful mnemonic function in vivo.
Collapse
Affiliation(s)
- Mengwen Zhu
- Department of Anesthesiology, University of Wisconsin-Madison, Madison, WI, 53705, USA.
| | - Mark G Perkins
- Department of Anesthesiology, University of Wisconsin-Madison, Madison, WI, 53705, USA.
| | - Richard Lennertz
- Department of Anesthesiology, University of Wisconsin-Madison, Madison, WI, 53705, USA.
| | - Alifayaz Abdulzahir
- Department of Anesthesiology, University of Wisconsin-Madison, Madison, WI, 53705, USA.
| | - Robert A Pearce
- Department of Anesthesiology, University of Wisconsin-Madison, Madison, WI, 53705, USA.
| |
Collapse
|
22
|
Doublet T, Nosrati M, Kentros CG. Social Learning of a Spatial Task by Observation Alone. Front Behav Neurosci 2022; 16:902675. [PMID: 35910679 PMCID: PMC9325960 DOI: 10.3389/fnbeh.2022.902675] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 06/10/2022] [Indexed: 11/16/2022] Open
Abstract
Interactions between conspecifics are central to the acquisition of useful memories in the real world. Observational learning, i.e., learning a task by observing the success or failure of others, has been reported in many species, including rodents. However, previous work in rats with NMDA-receptor blockade has shown that even extensive observation of an unexplored space through a clear barrier is not sufficient to generate a stable hippocampal representation of that space. This raises the question of whether rats can learn a spatial task in a purely observed space from watching a conspecific, and if so, does this somehow stabilize their hippocampal representation? To address these questions, we designed an observational spatial task in a two-part environment that is nearly identical to that of the aforementioned electrophysiological study, in which an observer rat watches a demonstrator animal to learn the location of a hidden reward. Our results demonstrate that rats do not need to physically explore an environment to learn a reward location, provided a conspecific demonstrates where it is. We also show that the behavioral memory is not affected by NMDA receptor blockade, suggesting that the spatial representation underlying the behavior has been consolidated by observation alone.
Collapse
|
23
|
Abstract
When navigating through space, we must maintain a representation of our position in real time; when recalling a past episode, a memory can come back in a flash. Interestingly, the brain's spatial representation system, including the hippocampus, supports these two distinct timescale functions. How are neural representations of space used in the service of both real-world navigation and internal mnemonic processes? Recent progress has identified sequences of hippocampal place cells, evolving at multiple timescales in accordance with either navigational behaviors or internal oscillations, that underlie these functions. We review experimental findings on experience-dependent modulation of these sequential representations and consider how they link real-world navigation to time-compressed memories. We further discuss recent work suggesting the prevalence of these sequences beyond hippocampus and propose that these multiple-timescale mechanisms may represent a general algorithm for organizing cell assemblies, potentially unifying the dual roles of the spatial representation system in memory and navigation.
Collapse
Affiliation(s)
- Wenbo Tang
- Graduate Program in Neuroscience, Brandeis University, Waltham, Massachusetts, USA;
| | - Shantanu P Jadhav
- Neuroscience Program, Department of Psychology, and Volen National Center for Complex Systems, Brandeis University, Waltham, Massachusetts, USA;
| |
Collapse
|
24
|
Rizzello E, Martin SK, Rouine J, Callaghan C, Mathiasen ML, O'Mara SM. Place Cells in the Claustrum Remap Under NMDA Receptor Control. Eur J Neurosci 2022; 56:3825-3838. [PMID: 35658087 PMCID: PMC9543514 DOI: 10.1111/ejn.15726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 05/18/2022] [Indexed: 11/29/2022]
Abstract
Place cells are cells that exhibit location‐dependent responses; they have mostly been studied in the hippocampus. Place cells have also been reported in the rat claustrum, an underexplored paracortical region with extensive corto‐cortical connectivity. It has been hypothesised that claustral neuronal responses are anchored to cortical visual inputs. We show rat claustral place cells remap when visual inputs are eliminated from the environment, and that this remapping is NMDA‐receptor‐dependent. Eliminating visual input decreases claustral delta‐band oscillatory activity, increases theta‐band oscillatory activity, and increases simultaneously recorded visual cortical activity. We conclude that, like the hippocampus, claustral place field remapping might be mediated by NMDA receptor activity, and is modulated by visual cortical inputs.
Collapse
Affiliation(s)
- Emanuela Rizzello
- School of Psychology and Institute of Neuroscience, Trinity College, Dublin - the University of Dublin, College Green, Ireland
| | - Seán K Martin
- School of Psychology and Institute of Neuroscience, Trinity College, Dublin - the University of Dublin, College Green, Ireland
| | - Jennifer Rouine
- School of Psychology and Institute of Neuroscience, Trinity College, Dublin - the University of Dublin, College Green, Ireland
| | - Charlotte Callaghan
- School of Psychology and Institute of Neuroscience, Trinity College, Dublin - the University of Dublin, College Green, Ireland
| | - Mathias L Mathiasen
- School of Psychology, Cardiff University, Cardiff, Wales, United Kingdom.,Current address: Department of Veterinary and Animal Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Shane M O'Mara
- School of Psychology and Institute of Neuroscience, Trinity College, Dublin - the University of Dublin, College Green, Ireland
| |
Collapse
|
25
|
Khalife MR, Scott RC, Hernan AE. Mechanisms for Cognitive Impairment in Epilepsy: Moving Beyond Seizures. Front Neurol 2022; 13:878991. [PMID: 35645970 PMCID: PMC9135108 DOI: 10.3389/fneur.2022.878991] [Citation(s) in RCA: 7] [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: 02/18/2022] [Accepted: 04/19/2022] [Indexed: 11/13/2022] Open
Abstract
There has been a major emphasis on defining the role of seizures in the causation of cognitive impairments like memory deficits in epilepsy. Here we focus on an alternative hypothesis behind these deficits, emphasizing the mechanisms of information processing underlying healthy cognition characterized as rate, temporal and population coding. We discuss the role of the underlying etiology of epilepsy in altering neural networks thereby leading to both the propensity for seizures and the associated cognitive impairments. In addition, we address potential treatments that can recover the network function in the context of a diseased brain, thereby improving both seizure and cognitive outcomes simultaneously. This review shows the importance of moving beyond seizures and approaching the deficits from a system-level perspective with the guidance of network neuroscience.
Collapse
Affiliation(s)
- Mohamed R. Khalife
- Division of Neuroscience, Nemours Children's Health, Wilmington, DE, United States
- Psychological and Brain Sciences, University of Delaware, Newark, DE, United States
| | - Rod C. Scott
- Division of Neuroscience, Nemours Children's Health, Wilmington, DE, United States
- Psychological and Brain Sciences, University of Delaware, Newark, DE, United States
- Institute of Child Health, Neurosciences Unit University College London, London, United Kingdom
| | - Amanda E. Hernan
- Division of Neuroscience, Nemours Children's Health, Wilmington, DE, United States
- Psychological and Brain Sciences, University of Delaware, Newark, DE, United States
| |
Collapse
|
26
|
Ratner MH, Farb DH. Probing the Neural Circuitry Targets of Neurotoxicants In Vivo Through High Density Silicon Probe Brain Implants. FRONTIERS IN TOXICOLOGY 2022; 4:836427. [PMID: 35548683 PMCID: PMC9081674 DOI: 10.3389/ftox.2022.836427] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 03/22/2022] [Indexed: 12/24/2022] Open
Abstract
Adverse effects of drugs on the human nervous system are rarely possible to anticipate based on preclinical neurotoxicity data, thus propagating the centuries long single most important obstacle to drug discovery and development for disorders of the nervous system. An emerging body of evidence indicates that in vivo electrophysiology using chronically implanted high-density electrodes (ciHDE) in freely moving animals is a rigorous method with enhanced potential for use in translational research. In particular, the structure and function of the hippocampal trisynaptic circuit (HTC) is conserved from rodents to primates, including Homo sapiens, suggesting that the effects of therapeutic agents and other potential neurologically active agents, whether beneficial or adverse, are likely to translate across species when interrogated using a conserved neural circuitry platform. This review explores science advances in the rapidly moving field of in vivo ciHDE in animal models of learning and memory. For this reason we focus on the HTC, where substantial research has investigated neural circuitry level responses and specific behaviors that reflect memory permitting a test of the ground truth validity of the findings. Examples of changes in neural network activity induced by endogenous neurotoxicants associated with neurodegenerative diseases, as well as exogenous therapeutics, drugs, and neurotoxicants are presented. Several illustrative examples of relevant findings that involve longer range neural circuitry outside of the HTC are discussed. Lastly, the limitations of in vivo ciHDE as applied to preclinical neurotoxicology are discussed with a view toward leveraging circuitry level actions to enhance our ability to project the specificity of in vitro target engagement with the desired psychopharmacological or neurological outcome. At the same time, the goal of reducing or eliminating significant neurotoxic adverse events in human is the desired endpoint. We believe that this approach will lead to enhanced discovery of high value neuroactive therapeutics that target neural circuitry domains as their primary mechanism of action, thus enhancing their ultimate contribution toward discovery of precision therapeutics.
Collapse
Affiliation(s)
- Marcia H. Ratner
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA, United States
- *Correspondence: Marcia H. Ratner,
| | - David H. Farb
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA, United States
- Center for Systems Neuroscience, Boston University, Boston, MA, United States
| |
Collapse
|
27
|
Marks WD, Yokose J, Kitamura T, Ogawa SK. Neuronal Ensembles Organize Activity to Generate Contextual Memory. Front Behav Neurosci 2022; 16:805132. [PMID: 35368306 PMCID: PMC8965349 DOI: 10.3389/fnbeh.2022.805132] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 02/14/2022] [Indexed: 11/17/2022] Open
Abstract
Contextual learning is a critical component of episodic memory and important for living in any environment. Context can be described as the attributes of a location that are not the location itself. This includes a variety of non-spatial information that can be derived from sensory systems (sounds, smells, lighting, etc.) and internal state. In this review, we first address the behavioral underpinnings of contextual memory and the development of context memory theory, with a particular focus on the contextual fear conditioning paradigm as a means of assessing contextual learning and the underlying processes contributing to it. We then present the various neural centers that play roles in contextual learning. We continue with a discussion of the current knowledge of the neural circuitry and physiological processes that underlie contextual representations in the Entorhinal cortex-Hippocampal (EC-HPC) circuit, as the most well studied contributor to contextual memory, focusing on the role of ensemble activity as a representation of context with a description of remapping, and pattern separation and completion in the processing of contextual information. We then discuss other critical regions involved in contextual memory formation and retrieval. We finally consider the engram assembly as an indicator of stored contextual memories and discuss its potential contribution to contextual memory.
Collapse
Affiliation(s)
- William D. Marks
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Jun Yokose
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Takashi Kitamura
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, United States
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Sachie K. Ogawa
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, United States
| |
Collapse
|
28
|
Keith RE, Ogoe RH, Dumas TC. Behind the scenes: Are latent memories supported by calcium independent plasticity? Hippocampus 2022; 32:73-88. [PMID: 33905147 PMCID: PMC8548406 DOI: 10.1002/hipo.23332] [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: 11/11/2020] [Revised: 04/08/2021] [Accepted: 04/11/2021] [Indexed: 02/03/2023]
Abstract
N-methyl-D-aspartate receptors (NMDARs) can be considered to be the de facto "plasticity" receptors in the brain due to their central role in the activity-dependent modification of neuronal morphology and synaptic transmission. Since the 1980s, research on NMDARs has focused on the second messenger properties of calcium and the downstream signaling pathways that mediate alterations in neural form and function. Recently, NMDARs were shown to drive activity-dependent synaptic plasticity without calcium influx. How this "nonionotropic" plasticity occurs in vitro is becoming clearer, but research on its involvement in behavior and cognition is in its infancy. There is a partial overlap in the downstream signaling molecules that are involved in ionotropic and nonionotropic NMDAR-dependent plasticity. Given this, and prior studies of the cognitive impacts of ionotropic NMDAR plasticity, a preliminary model explaining how NMDAR nonionotropic plasticity affects learning and memory can be established. We hypothesize that nonionotropic NMDAR plasticity takes part in latent memory encoding in immature rodents through nonassociative depression of synaptic efficacy, and possibly shrinking of dendritic spines. Further, the late postnatal alteration in NMDAR composition in the hippocampus appears to reduce nonionotropic signaling and remove a restriction on memory retrieval. This framework substantially alters the canonical model of NMDAR involvement in spatial cognition and hippocampal maturation and provides novel and exciting inroads for future studies.
Collapse
Affiliation(s)
- Rachel E. Keith
- Interdisciplinary Program in Neuroscience, College of Science, George Mason University, Fairfax, Virginia
| | - Richard H. Ogoe
- Department of Psychology, College of Humanities and Social Sciences, George Mason University, Fairfax, Virginia
| | - Theodore C. Dumas
- Interdisciplinary Program in Neuroscience, College of Science, George Mason University, Fairfax, Virginia,Department of Psychology, College of Humanities and Social Sciences, George Mason University, Fairfax, Virginia
| |
Collapse
|
29
|
Laha K, Zhu M, Gemperline E, Rau V, Li L, Fanselow MS, Lennertz R, Pearce RA. CPP impairs contextual learning at concentrations below those that block pyramidal neuron NMDARs and LTP in the CA1 region of the hippocampus. Neuropharmacology 2022; 202:108846. [PMID: 34687710 PMCID: PMC8627488 DOI: 10.1016/j.neuropharm.2021.108846] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 09/29/2021] [Accepted: 10/15/2021] [Indexed: 01/03/2023]
Abstract
Drugs that block N-methyl-d-aspartate receptors (NMDARs) suppress hippocampus-dependent memory formation; they also block long-term potentiation (LTP), a cellular model of learning and memory. However, the fractional block that is required to achieve these effects is unknown. Here, we measured the dose-dependent suppression of contextual memory in vivo by systemic administration of the competitive antagonist (R,S)-3-(2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid (CPP); in parallel, we measured the concentration-dependent block by CPP of NMDAR-mediated synapses and LTP of excitatory synapses in hippocampal brain slices in vitro. We found that the dose of CPP that suppresses contextual memory in vivo (EC50 = 2.3 mg/kg) corresponds to a free concentration of 53 nM. Surprisingly, applying this concentration of CPP to hippocampal brain slices had no effect on the NMDAR component of evoked field excitatory postsynaptic potentials (fEPSPNMDA), or on LTP. Rather, the IC50 for blocking the fEPSPNMDA was 434 nM, and for blocking LTP was 361 nM - both nearly an order of magnitude higher. We conclude that memory impairment produced by systemically administered CPP is not due primarily to its blockade of NMDARs on hippocampal pyramidal neurons. Rather, systemic CPP suppresses memory formation by actions elsewhere in the memory-encoding circuitry.
Collapse
Affiliation(s)
- Kurt Laha
- Department of Anesthesiology, University of Wisconsin-Madison, Madison, WI, USA.
| | - Mengwen Zhu
- Department of Anesthesiology, University of Wisconsin-Madison, Madison, WI, USA.
| | - Erin Gemperline
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, USA.
| | - Vinuta Rau
- Department of Anesthesiology, University of California-San Francisco, San Francisco, CA, USA.
| | - Lingjun Li
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, USA; School of Pharmacy, University of Wisconsin-Madison, Madison, WI, USA.
| | - Michael S Fanselow
- Departments of Psychology and Psychiatry, University of California, Los Angeles, Los Angeles, CA, USA.
| | - Richard Lennertz
- Department of Anesthesiology, University of Wisconsin-Madison, Madison, WI, USA.
| | - Robert A Pearce
- Department of Anesthesiology, University of Wisconsin-Madison, Madison, WI, USA.
| |
Collapse
|
30
|
Linking hippocampal multiplexed tuning, Hebbian plasticity and navigation. Nature 2021; 599:442-448. [PMID: 34671157 DOI: 10.1038/s41586-021-03989-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 09/01/2021] [Indexed: 11/08/2022]
Abstract
Three major pillars of hippocampal function are spatial navigation1, Hebbian synaptic plasticity2 and spatial selectivity3. The hippocampus is also implicated in episodic memory4, but the precise link between these four functions is missing. Here we report the multiplexed selectivity of dorsal CA1 neurons while rats performed a virtual navigation task using only distal visual cues5, similar to the standard water maze test of spatial memory1. Neural responses primarily encoded path distance from the start point and the head angle of rats, with a weak allocentric spatial component similar to that in primates but substantially weaker than in rodents in the real world. Often, the same cells multiplexed and encoded path distance, angle and allocentric position in a sequence, thus encoding a journey-specific episode. The strength of neural activity and tuning strongly correlated with performance, with a temporal relationship indicating neural responses influencing behaviour and vice versa. Consistent with computational models of associative and causal Hebbian learning6,7, neural responses showed increasing clustering8 and became better predictors of behaviourally relevant variables, with the average neurometric curves exceeding and converging to psychometric curves. Thus, hippocampal neurons multiplex and exhibit highly plastic, task- and experience-dependent tuning to path-centric and allocentric variables to form episodic sequences supporting navigation.
Collapse
|
31
|
Michon F, Krul E, Sun JJ, Kloosterman F. Single-trial dynamics of hippocampal spatial representations are modulated by reward value. Curr Biol 2021; 31:4423-4435.e5. [PMID: 34416178 DOI: 10.1016/j.cub.2021.07.058] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 04/26/2021] [Accepted: 07/23/2021] [Indexed: 10/20/2022]
Abstract
Reward value is known to modulate learning speed in spatial memory tasks, but little is known about its influence on the dynamical changes in hippocampal spatial representations. Here, we monitored the trial-to-trial changes in hippocampal place cell activity during the acquisition of place-reward associations with varying reward size. We show a faster reorganization and stabilization of the hippocampal place map when a goal location is associated with a large reward. The reorganization is driven by both rate changes and the appearance and disappearance of place fields. The occurrence of hippocampal replay activity largely followed the dynamics of changes in spatial representations. Replay patterns became more selectively tuned toward behaviorally relevant experiences over the course of learning via the refined contributions of specific cell subpopulations. These results suggest that high reward value enhances memory retention by accelerating the formation and stabilization of the hippocampal cognitive map and selectively enhancing its reactivation during learning.
Collapse
Affiliation(s)
- Frédéric Michon
- NERF, Kapeldreef 75, 3001 Leuven, Belgium; Brain & Cognition, KU Leuven, Tiensestraat 102, 3000 Leuven, Belgium; VIB, Rijvisschestraat 120, 9052 Ghent, Belgium
| | - Esther Krul
- NERF, Kapeldreef 75, 3001 Leuven, Belgium; Brain & Cognition, KU Leuven, Tiensestraat 102, 3000 Leuven, Belgium
| | - Jyh-Jang Sun
- NERF, Kapeldreef 75, 3001 Leuven, Belgium; imec, Remisebosweg 1, 3001 Leuven, Belgium
| | - Fabian Kloosterman
- NERF, Kapeldreef 75, 3001 Leuven, Belgium; Brain & Cognition, KU Leuven, Tiensestraat 102, 3000 Leuven, Belgium; VIB, Rijvisschestraat 120, 9052 Ghent, Belgium; imec, Remisebosweg 1, 3001 Leuven, Belgium.
| |
Collapse
|
32
|
Cholvin T, Hainmueller T, Bartos M. The hippocampus converts dynamic entorhinal inputs into stable spatial maps. Neuron 2021; 109:3135-3148.e7. [PMID: 34619088 PMCID: PMC8516433 DOI: 10.1016/j.neuron.2021.09.019] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 05/31/2021] [Accepted: 09/09/2021] [Indexed: 11/29/2022]
Abstract
The medial entorhinal cortex (MEC)-hippocampal network plays a key role in the processing, storage, and recall of spatial information. However, how the spatial code provided by MEC inputs relates to spatial representations generated by principal cell assemblies within hippocampal subfields remains enigmatic. To investigate this coding relationship, we employed two-photon calcium imaging in mice navigating through dissimilar virtual environments. Imaging large MEC bouton populations revealed spatially tuned activity patterns. MEC inputs drastically changed their preferred spatial field locations between environments, whereas hippocampal cells showed lower levels of place field reconfiguration. Decoding analysis indicated that higher place field reliability and larger context-dependent activity-rate differences allow low numbers of principal cells, particularly in the DG and CA1, to provide information about location and context more accurately and rapidly than MEC inputs. Thus, conversion of dynamic MEC inputs into stable spatial hippocampal maps may enable fast encoding and efficient recall of spatio-contextual information. MEC inputs to the DG, CA3, and CA1 show different spatial coding properties MEC inputs remap even more strongly than hippocampal principal cells Hippocampal principal cell activity is more reliable and stable than their MEC inputs Hippocampal principal cells allow improved spatial and contextual readout
Collapse
Affiliation(s)
- Thibault Cholvin
- Institute for Physiology I, University of Freiburg, Medical Faculty, Freiburg 79104, Germany
| | - Thomas Hainmueller
- NYU Neuroscience Institute, 435 East 30th Street, New York, NY 10016, USA
| | - Marlene Bartos
- Institute for Physiology I, University of Freiburg, Medical Faculty, Freiburg 79104, Germany.
| |
Collapse
|
33
|
Plasticity between visual input pathways and the head direction system. Curr Opin Neurobiol 2021; 71:60-68. [PMID: 34619578 DOI: 10.1016/j.conb.2021.08.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Accepted: 08/26/2021] [Indexed: 11/21/2022]
Abstract
Animals can maintain a stable sense of direction even when they navigate in novel environments, but how the animal's brain interprets and encodes unfamiliar sensory information in its navigation system to maintain a stable sense of direction is a mystery. Recent studies have suggested that distinct brain structures of mammals and insects have evolved to solve this common problem with strategies that share computational principles; specifically, a network structure called a ring attractor maintains the sense of direction. Initially, in a novel environment, the animal's sense of direction relies on self-motion cues. Over time, the mapping from visual inputs to head direction cells, responsible for the sense of direction, is established via experience-dependent plasticity. Yet the mechanisms that facilitate acquiring a world-centered sense of direction, how many environments can be stored in memory, and what visual features are selected, all remain unknown. Thanks to recent advances in large scale physiological recording, genetic tools, and theory, these mechanisms may soon be revealed.
Collapse
|
34
|
Fraser EG, Makarowski T, McDonald RJ. Perforant path inputs to hippocampal subfields predict heterogeneous AMPA receptor subunit expression following rapid new spatial learning in a novel context. Eur J Neurosci 2021; 54:6740-6761. [PMID: 34214189 DOI: 10.1111/ejn.15380] [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: 11/21/2019] [Revised: 06/18/2021] [Accepted: 06/28/2021] [Indexed: 11/27/2022]
Abstract
The hippocampus plays a critical role in spatial learning and memory. Its contribution to support these kinds of learning and memory functions relies on synaptic plasticity and related molecular mechanisms, well documented in the long-term potentiation (LTP) literature. The present experiment measures AMPA subunit expression, in a ratio of GluA2:GluA1 as an indicator of plasticity across the hippocampus, in rats that underwent new spatial learning in either a familiar or novel context. Statistically significant effects in this plasticity indicator were observed of context condition, time after task and hippocampal subfield. Based on the strong inputs of entorhinal cortex to hippocampus, we also identified differences in GluA2:GluA1 expression trends between time points and room conditions that mirror trends in medial and lateral entorhinal cortex connectivity between new room and same room context learning, respectively. Across the transverse axis in infrapyramidal dentate gyrus, CA3 and CA1, plasticity followed entorhinal cortex projection patterns. Along the transverse axis in the suprapyramidal blade of the dentate gyrus, and along the long axis in dentate gyrus and CA3, results did not follow entorhinal cortex subregion projection patterns. These latter results may be indicative of pattern separation in the dentate gyrus and emotional triage functions of the ventral hippocampus.
Collapse
Affiliation(s)
- Ellen G Fraser
- The Canadian Centre for Behavioural Neuroscience, Department of Neuroscience, The University of Lethbridge, Lethbridge, Alberta, Canada
| | - Ty Makarowski
- The Canadian Centre for Behavioural Neuroscience, Department of Neuroscience, The University of Lethbridge, Lethbridge, Alberta, Canada
| | - Robert J McDonald
- The Canadian Centre for Behavioural Neuroscience, Department of Neuroscience, The University of Lethbridge, Lethbridge, Alberta, Canada
| |
Collapse
|
35
|
Ness N, Schultz SR. A computational grid-to-place-cell transformation model indicates a synaptic driver of place cell impairment in early-stage Alzheimer's Disease. PLoS Comput Biol 2021; 17:e1009115. [PMID: 34133417 PMCID: PMC8238223 DOI: 10.1371/journal.pcbi.1009115] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 06/28/2021] [Accepted: 05/26/2021] [Indexed: 12/23/2022] Open
Abstract
Alzheimer's Disease (AD) is characterized by progressive neurodegeneration and cognitive impairment. Synaptic dysfunction is an established early symptom, which correlates strongly with cognitive decline, and is hypothesised to mediate the diverse neuronal network abnormalities observed in AD. However, how synaptic dysfunction contributes to network pathology and cognitive impairment in AD remains elusive. Here, we present a grid-cell-to-place-cell transformation model of long-term CA1 place cell dynamics to interrogate the effect of synaptic loss on network function and environmental representation. Synapse loss modelled after experimental observations in the APP/PS1 mouse model was found to induce firing rate alterations and place cell abnormalities that have previously been observed in AD mouse models, including enlarged place fields and lower across-session stability of place fields. Our results support the hypothesis that synaptic dysfunction underlies cognitive deficits, and demonstrate how impaired environmental representation may arise in the early stages of AD. We further propose that dysfunction of excitatory and inhibitory inputs to CA1 pyramidal cells may cause distinct impairments in place cell function, namely reduced stability and place map resolution.
Collapse
Affiliation(s)
- Natalie Ness
- Centre for Neurotechnology and Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Simon R. Schultz
- Centre for Neurotechnology and Department of Bioengineering, Imperial College London, London, United Kingdom
| |
Collapse
|
36
|
Grossberg S. A Neural Model of Intrinsic and Extrinsic Hippocampal Theta Rhythms: Anatomy, Neurophysiology, and Function. Front Syst Neurosci 2021; 15:665052. [PMID: 33994965 PMCID: PMC8113652 DOI: 10.3389/fnsys.2021.665052] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 03/29/2021] [Indexed: 11/21/2022] Open
Abstract
This article describes a neural model of the anatomy, neurophysiology, and functions of intrinsic and extrinsic theta rhythms in the brains of multiple species. Topics include how theta rhythms were discovered; how theta rhythms organize brain information processing into temporal series of spatial patterns; how distinct theta rhythms occur within area CA1 of the hippocampus and between the septum and area CA3 of the hippocampus; what functions theta rhythms carry out in different brain regions, notably CA1-supported functions like learning, recognition, and memory that involve visual, cognitive, and emotional processes; how spatial navigation, adaptively timed learning, and category learning interact with hippocampal theta rhythms; how parallel cortical streams through the lateral entorhinal cortex (LEC) and the medial entorhinal cortex (MEC) represent the end-points of the What cortical stream for perception and cognition and the Where cortical stream for spatial representation and action; how the neuromodulator acetylcholine interacts with the septo-hippocampal theta rhythm and modulates category learning; what functions are carried out by other brain rhythms, such as gamma and beta oscillations; and how gamma and beta oscillations interact with theta rhythms. Multiple experimental facts about theta rhythms are unified and functionally explained by this theoretical synthesis.
Collapse
Affiliation(s)
- Stephen Grossberg
- Center for Adaptive Systems, Department of Mathematics and Statistics, Department of Psychological and Brain Sciences, and Department of Biomedical Engineering, Boston University, Boston, MA, United States
| |
Collapse
|
37
|
Sato M, Mizuta K, Islam T, Kawano M, Sekine Y, Takekawa T, Gomez-Dominguez D, Schmidt A, Wolf F, Kim K, Yamakawa H, Ohkura M, Lee MG, Fukai T, Nakai J, Hayashi Y. Distinct Mechanisms of Over-Representation of Landmarks and Rewards in the Hippocampus. Cell Rep 2021; 32:107864. [PMID: 32640229 DOI: 10.1016/j.celrep.2020.107864] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 04/06/2020] [Accepted: 06/16/2020] [Indexed: 10/23/2022] Open
Abstract
In the hippocampus, locations associated with salient features are represented by a disproportionately large number of neurons, but the cellular and molecular mechanisms underlying this over-representation remain elusive. Using longitudinal calcium imaging in mice learning to navigate in virtual reality, we find that the over-representation of reward and landmark locations are mediated by persistent and separable subsets of neurons, with distinct time courses of emergence and differing underlying molecular mechanisms. Strikingly, we find that in mice lacking Shank2, an autism spectrum disorder (ASD)-linked gene encoding an excitatory postsynaptic scaffold protein, the learning-induced over-representation of landmarks was absent whereas the over-representation of rewards was substantially increased, as was goal-directed behavior. These findings demonstrate that multiple hippocampal coding processes for unique types of salient features are distinguished by a Shank2-dependent mechanism and suggest that abnormally distorted hippocampal salience mapping may underlie cognitive and behavioral abnormalities in a subset of ASDs.
Collapse
Affiliation(s)
- Masaaki Sato
- RIKEN Center for Brain Science, Wako, Saitama 351-0198, Japan; PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Japan; Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan; Brain and Body System Science Institute, Saitama University, Saitama 338-8570, Japan; RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan.
| | - Kotaro Mizuta
- RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan; Department of Pharmacology, Kyoto University Graduate School of Medicine, Kyoto 606-8501, Japan
| | - Tanvir Islam
- RIKEN Center for Brain Science, Wako, Saitama 351-0198, Japan; RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan
| | - Masako Kawano
- RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan
| | - Yukiko Sekine
- RIKEN Center for Brain Science, Wako, Saitama 351-0198, Japan; RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan
| | - Takashi Takekawa
- RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan; Faculty of Informatics, Kogakuin University, Tokyo 163-8677, Japan
| | - Daniel Gomez-Dominguez
- RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan; Instituto Cajal, CSIC, Madrid 28002, Spain
| | - Alexander Schmidt
- Department of Pharmacology, Kyoto University Graduate School of Medicine, Kyoto 606-8501, Japan; Max Planck Institute for Dynamics and Self-Organization, Göttingen 37077, Germany; Max Planck Institute for Experimental Medicine, Göttingen 37075, Germany; Campus Institute for Dynamics of Biological Networks, Göttingen 37075, Germany; Center for Biostructural Imaging of Neurodegeneration, Göttingen 37075, Germany
| | - Fred Wolf
- Max Planck Institute for Dynamics and Self-Organization, Göttingen 37077, Germany; Max Planck Institute for Experimental Medicine, Göttingen 37075, Germany; Campus Institute for Dynamics of Biological Networks, Göttingen 37075, Germany; Center for Biostructural Imaging of Neurodegeneration, Göttingen 37075, Germany
| | - Karam Kim
- RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan
| | - Hiroshi Yamakawa
- RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan; The University of Tokyo, Tokyo 113-8654, Japan; Whole Brain Architecture Initiative, Tokyo 133-0057, Japan; RIKEN Center for Biosystems Dynamics Research, Osaka 565-0874, Japan
| | - Masamichi Ohkura
- Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan; Brain and Body System Science Institute, Saitama University, Saitama 338-8570, Japan
| | - Min Goo Lee
- National Creative Research Initiative Center for Cell Membrane Transport, Yonsei University College of Medicine, Seoul 120-752, Republic of Korea
| | - Tomoki Fukai
- Okinawa Institute of Science and Technology, Onna, Okinawa, 904-0495, Japan
| | - Junichi Nakai
- Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan; Brain and Body System Science Institute, Saitama University, Saitama 338-8570, Japan
| | - Yasunori Hayashi
- Brain and Body System Science Institute, Saitama University, Saitama 338-8570, Japan; RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan; Department of Pharmacology, Kyoto University Graduate School of Medicine, Kyoto 606-8501, Japan.
| |
Collapse
|
38
|
Yang W, Chini M, Pöpplau JA, Formozov A, Dieter A, Piechocinski P, Rais C, Morellini F, Sporns O, Hanganu-Opatz IL, Wiegert JS. Anesthetics fragment hippocampal network activity, alter spine dynamics, and affect memory consolidation. PLoS Biol 2021; 19:e3001146. [PMID: 33793545 PMCID: PMC8016109 DOI: 10.1371/journal.pbio.3001146] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 02/15/2021] [Indexed: 02/07/2023] Open
Abstract
General anesthesia is characterized by reversible loss of consciousness accompanied by transient amnesia. Yet, long-term memory impairment is an undesirable side effect. How different types of general anesthetics (GAs) affect the hippocampus, a brain region central to memory formation and consolidation, is poorly understood. Using extracellular recordings, chronic 2-photon imaging, and behavioral analysis, we monitor the effects of isoflurane (Iso), medetomidine/midazolam/fentanyl (MMF), and ketamine/xylazine (Keta/Xyl) on network activity and structural spine dynamics in the hippocampal CA1 area of adult mice. GAs robustly reduced spiking activity, decorrelated cellular ensembles, albeit with distinct activity signatures, and altered spine dynamics. CA1 network activity under all 3 anesthetics was different to natural sleep. Iso anesthesia most closely resembled unperturbed activity during wakefulness and sleep, and network alterations recovered more readily than with Keta/Xyl and MMF. Correspondingly, memory consolidation was impaired after exposure to Keta/Xyl and MMF, but not Iso. Thus, different anesthetics distinctly alter hippocampal network dynamics, synaptic connectivity, and memory consolidation, with implications for GA strategy appraisal in animal research and clinical settings.
Collapse
Affiliation(s)
- Wei Yang
- Research Group Synaptic Wiring and Information Processing, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Mattia Chini
- Institute of Developmental Neurophysiology, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Jastyn A. Pöpplau
- Institute of Developmental Neurophysiology, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Andrey Formozov
- Research Group Synaptic Wiring and Information Processing, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Alexander Dieter
- Research Group Synaptic Wiring and Information Processing, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Patrick Piechocinski
- Research Group Synaptic Wiring and Information Processing, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Cynthia Rais
- Research Group Synaptic Wiring and Information Processing, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Fabio Morellini
- Research Group Behavioral Biology, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Olaf Sporns
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana, United States of America
- Indiana University Network Science Institute, Indiana University, Bloomington, Indiana, United States of America
| | - Ileana L. Hanganu-Opatz
- Institute of Developmental Neurophysiology, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - J. Simon Wiegert
- Research Group Synaptic Wiring and Information Processing, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- * E-mail:
| |
Collapse
|
39
|
Schlesiger MI, Ruff T, MacLaren DAA, Barriuso-Ortega I, Saidov KM, Yen TY, Monyer H. Two septal-entorhinal GABAergic projections differentially control coding properties of spatially tuned neurons in the medial entorhinal cortex. Cell Rep 2021; 34:108801. [PMID: 33657367 DOI: 10.1016/j.celrep.2021.108801] [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: 06/03/2020] [Revised: 12/23/2020] [Accepted: 02/05/2021] [Indexed: 12/20/2022] Open
Abstract
Septal parvalbumin-expressing (PV+) and calbindin-expressing (CB+) projections inhibit low-threshold and fast-spiking interneurons, respectively, in the medial entorhinal cortex (MEC). We investigate how the two inputs control neuronal activity in the MEC in freely moving mice. Stimulation of PV+ and CB+ terminals causes disinhibition of spatially tuned MEC neurons, but exerts differential effects on temporal coding and burst firing. Thus, recruitment of PV+ projections disrupts theta-rhythmic firing of MEC neurons, while stimulation of CB+ projections increases burst firing of grid cells and enhances phase precession in a cell-type-specific manner. Inactivation of septal PV+ or CB+ neurons differentially affects context, reference, and working memory. Together, our results reveal how specific connectivity of septal GABAergic projections with MEC interneurons translates into differential modulation of MEC neuronal coding.
Collapse
Affiliation(s)
- Magdalene Isabell Schlesiger
- Department of Clinical Neurobiology at the Medical Faculty of Heidelberg University and German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Tobias Ruff
- Department of Clinical Neurobiology at the Medical Faculty of Heidelberg University and German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Duncan Archibald Allan MacLaren
- Department of Clinical Neurobiology at the Medical Faculty of Heidelberg University and German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Isabel Barriuso-Ortega
- Department of Clinical Neurobiology at the Medical Faculty of Heidelberg University and German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Khalid Magomedovich Saidov
- Department of Clinical Neurobiology at the Medical Faculty of Heidelberg University and German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Ting-Yun Yen
- Department of Clinical Neurobiology at the Medical Faculty of Heidelberg University and German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Hannah Monyer
- Department of Clinical Neurobiology at the Medical Faculty of Heidelberg University and German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany.
| |
Collapse
|
40
|
Dillingham CM, Milczarek MM, Perry JC, Vann SD. Time to put the mammillothalamic pathway into context. Neurosci Biobehav Rev 2021; 121:60-74. [PMID: 33309908 PMCID: PMC8137464 DOI: 10.1016/j.neubiorev.2020.11.031] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 10/10/2020] [Accepted: 11/13/2020] [Indexed: 12/11/2022]
Abstract
The medial diencephalon, in particular the mammillary bodies and anterior thalamic nuclei, has long been linked to memory and amnesia. The mammillary bodies provide a dense input into the anterior thalamic nuclei, via the mammillothalamic tract. In both animal models, and in patients, lesions of the mammillary bodies, mammillothalamic tract and anterior thalamic nuclei all produce severe impairments in temporal and contextual memory, yet it is uncertain why these regions are critical. Mounting evidence from electrophysiological and neural imaging studies suggests that mammillothalamic projections exercise considerable distal influence over thalamo-cortical and hippocampo-cortical interactions. Here, we outline how damage to the mammillary body-anterior thalamic axis, in both patients and animal models, disrupts behavioural performance on tasks that relate to contextual ("where") and temporal ("when") processing. Focusing on the medial mammillary nuclei as a possible 'theta-generator' (through their interconnections with the ventral tegmental nucleus of Gudden) we discuss how the mammillary body-anterior thalamic pathway may contribute to the mechanisms via which the hippocampus and neocortex encode representations of experience.
Collapse
Affiliation(s)
- Christopher M Dillingham
- School of Psychology, Neuroscience and Mental Health Research Institute, Cardiff University, Cardiff, CF10 3AT, UK
| | - Michal M Milczarek
- School of Psychology, Neuroscience and Mental Health Research Institute, Cardiff University, Cardiff, CF10 3AT, UK
| | - James C Perry
- School of Psychology, Neuroscience and Mental Health Research Institute, Cardiff University, Cardiff, CF10 3AT, UK
| | - Seralynne D Vann
- School of Psychology, Neuroscience and Mental Health Research Institute, Cardiff University, Cardiff, CF10 3AT, UK.
| |
Collapse
|
41
|
Lenck-Santini PP, Sakkaki S. Alterations of Neuronal Dynamics as a Mechanism for Cognitive Impairment in Epilepsy. Curr Top Behav Neurosci 2021; 55:65-106. [PMID: 33454922 DOI: 10.1007/7854_2020_193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Epilepsy is commonly associated with cognitive and behavioral deficits that dramatically affect the quality of life of patients. In order to identify novel therapeutic strategies aimed at reducing these deficits, it is critical first to understand the mechanisms leading to cognitive impairments in epilepsy. Traditionally, seizures and epileptiform activity in addition to neuronal injury have been considered to be the most significant contributors to cognitive dysfunction. In this review we however highlight the role of a new mechanism: alterations of neuronal dynamics, i.e. the timing at which neurons and networks receive and process neural information. These alterations, caused by the underlying etiologies of epilepsy syndromes, are observed in both animal models and patients in the form of abnormal oscillation patterns in unit firing, local field potentials, and electroencephalogram (EEG). Evidence suggests that such mechanisms significantly contribute to cognitive impairment in epilepsy, independently of seizures and interictal epileptiform activity. Therefore, therapeutic strategies directly targeting neuronal dynamics rather than seizure reduction may significantly benefit the quality of life of patients.
Collapse
Affiliation(s)
- Pierre-Pascal Lenck-Santini
- Aix-Marseille Université, INSERM, INMED, Marseille, France. .,Department of Neurological sciences, University of Vermont, Burlington, VT, USA.
| | - Sophie Sakkaki
- Department of Neurological sciences, University of Vermont, Burlington, VT, USA.,Université de. Montpellier, CNRS, INSERM, IGF, Montpellier, France
| |
Collapse
|
42
|
Miry O, Li J, Chen L. The Quest for the Hippocampal Memory Engram: From Theories to Experimental Evidence. Front Behav Neurosci 2021; 14:632019. [PMID: 33519396 PMCID: PMC7843437 DOI: 10.3389/fnbeh.2020.632019] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Accepted: 12/17/2020] [Indexed: 11/18/2022] Open
Abstract
More than a century after Richard Semon's theoretical proposal of the memory engram, technological advancements have finally enabled experimental access to engram cells and their functional contents. In this review, we summarize theories and their experimental support regarding hippocampal memory engram formation and function. Specifically, we discuss recent advances in the engram field which help to reconcile two main theories for how the hippocampus supports memory formation: The Memory Indexing and Cognitive Map theories. We also highlight the latest evidence for engram allocation mechanisms through which memories can be linked or separately encoded. Finally, we identify unanswered questions for future investigations, through which a more comprehensive understanding of memory formation and retrieval may be achieved.
Collapse
Affiliation(s)
- Omid Miry
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, United States
| | - Jie Li
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA, United States
| | - Lu Chen
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, United States.,Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA, United States
| |
Collapse
|
43
|
Ashby DM, Floresco SB, Phillips AG, McGirr A, Seamans JK, Wang YT. LTD is involved in the formation and maintenance of rat hippocampal CA1 place-cell fields. Nat Commun 2021; 12:100. [PMID: 33397954 PMCID: PMC7782827 DOI: 10.1038/s41467-020-20317-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Accepted: 11/25/2020] [Indexed: 01/29/2023] Open
Abstract
Hippocampal synaptic plasticity includes both long-term potentiation (LTP) and long-term depression (LTD) of synaptic strength, and has been implicated in shaping place field representations that form upon initial exposure to a novel environment. However, direct evidence causally linking either LTP or LTD to place fields remains limited. Here, we show that hippocampal LTD regulates the acute formation and maintenance of place fields using electrophysiology and blocking specifically LTD in freely-moving rats. We also show that exploration of a novel environment produces a widespread and pathway specific de novo synaptic depression in the dorsal hippocampus. Furthermore, disruption of this pathway-specific synaptic depression alters both the dynamics of place field formation and the stability of the newly formed place fields, affecting spatial memory in rats. These results suggest that activity-dependent synaptic depression is required for the acquisition and maintenance of novel spatial information.
Collapse
Affiliation(s)
- Donovan M Ashby
- Hotchkiss Brain Institute, University of Calgary, 3330 Hospital Drive NW, Calgary, T2N 4N1, AB, Canada
| | - Stan B Floresco
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2215 Wesbrook Mall, Vancouver, V6T 1Z7, BC, Canada
- Department of Psychology, University of British Columbia, 2136 West Mall, Vancouver, V6T 1Z4, BC, Canada
| | - Anthony G Phillips
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2215 Wesbrook Mall, Vancouver, V6T 1Z7, BC, Canada
- Department of Psychiatry, University of British Columbia, 2255 Wesbrook Mall, Vancouver, V6T 2A1, BC, Canada
| | - Alexander McGirr
- Hotchkiss Brain Institute, University of Calgary, 3330 Hospital Drive NW, Calgary, T2N 4N1, AB, Canada
- Department of Psychiatry, University of Calgary, 3330 Hospital Dr NW, Calgary, T2N 4N1, AB, Canada
| | - Jeremy K Seamans
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2215 Wesbrook Mall, Vancouver, V6T 1Z7, BC, Canada
- Department of Psychiatry, University of British Columbia, 2255 Wesbrook Mall, Vancouver, V6T 2A1, BC, Canada
| | - Yu Tian Wang
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2215 Wesbrook Mall, Vancouver, V6T 1Z7, BC, Canada.
- Department of Medicine, University of British Columbia, 2775 Laurel Street, 10th Floor, Vancouver, V5Z 1M9, BC, Canada.
| |
Collapse
|
44
|
Howe T, Blockeel AJ, Taylor H, Jones MW, Bazhenov M, Malerba P. NMDA receptors promote hippocampal sharp-wave ripples and the associated coactivity of CA1 pyramidal cells. Hippocampus 2020; 30:1356-1370. [PMID: 33112474 PMCID: PMC8645203 DOI: 10.1002/hipo.23276] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 10/05/2020] [Accepted: 10/15/2020] [Indexed: 10/10/2023]
Abstract
Hippocampal sharp-wave ripples (SWRs) support the reactivation of memory representations, relaying information to neocortex during "offline" and sleep-dependent memory consolidation. While blockade of NMDA receptors (NMDAR) is known to affect both learning and subsequent consolidation, the specific contributions of NMDAR activation to SWR-associated activity remain unclear. Here, we combine biophysical modeling with in vivo local field potential (LFP) and unit recording to quantify changes in SWR dynamics following inactivation of NMDAR. In a biophysical model of CA3-CA1 SWR activity, we find that NMDAR removal leads to reduced SWR density, but spares SWR properties such as duration, cell recruitment and ripple frequency. These predictions are confirmed by experiments in which NMDAR-mediated transmission in rats was inhibited using three different NMDAR antagonists, while recording dorsal CA1 LFP. In the model, loss of NMDAR-mediated conductances also induced a reduction in the proportion of cell pairs that co-activate significantly above chance across multiple events. Again, this prediction is corroborated by dorsal CA1 single-unit recordings, where the NMDAR blocker ketamine disrupted correlated spiking during SWR. Our results are consistent with a framework in which NMDA receptors both promote activation of SWR events and organize SWR-associated spiking content. This suggests that, while SWR are short-lived events emerging in fast excitatory-inhibitory networks, slower network components including NMDAR-mediated currents contribute to ripple density and promote consistency in the spiking content across ripples, underpinning mechanisms for fine-tuning of memory consolidation processes.
Collapse
Affiliation(s)
- Timothy Howe
- School of Physiology, Pharmacology and Neuroscience,
University of Bristol, Bristol, UK
| | - Anthony J. Blockeel
- School of Physiology, Pharmacology and Neuroscience,
University of Bristol, Bristol, UK
| | - Hannah Taylor
- School of Physiology, Pharmacology and Neuroscience,
University of Bristol, Bristol, UK
| | - Matthew W. Jones
- School of Physiology, Pharmacology and Neuroscience,
University of Bristol, Bristol, UK
| | - Maxim Bazhenov
- Department of Medicine, University of California San Diego,
La Jolla, California
| | - Paola Malerba
- School of Physiology, Pharmacology and Neuroscience,
University of Bristol, Bristol, UK
- Battelle Center for Mathematical Medicine, Columbus,
Ohio
| |
Collapse
|
45
|
Pedrosa V, Clopath C. The interplay between somatic and dendritic inhibition promotes the emergence and stabilization of place fields. PLoS Comput Biol 2020; 16:e1007955. [PMID: 32649658 PMCID: PMC7386595 DOI: 10.1371/journal.pcbi.1007955] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 07/28/2020] [Accepted: 05/15/2020] [Indexed: 01/10/2023] Open
Abstract
During the exploration of novel environments, place fields are rapidly formed in hippocampal CA1 neurons. Place cell firing rate increases in early stages of exploration of novel environments but returns to baseline levels in familiar environments. Although similar in amplitude and width, place fields in familiar environments are more stable than in novel environments. We propose a computational model of the hippocampal CA1 network, which describes the formation, dynamics and stabilization of place fields. We show that although somatic disinhibition is sufficient to form place fields, dendritic inhibition along with synaptic plasticity is necessary for place field stabilization. Our model suggests that place cell stability can be attributed to strong excitatory synaptic weights and strong dendritic inhibition. We show that the interplay between somatic and dendritic inhibition balances the increased excitatory weights, such that place cells return to their baseline firing rate after exploration. Our model suggests that different types of interneurons are essential to unravel the mechanisms underlying place field plasticity. Finally, we predict that artificially induced dendritic events can shift place fields even after place field stabilization.
Collapse
Affiliation(s)
- Victor Pedrosa
- Department of Bioengineering, Imperial College London, London, United Kingdom
- CAPES Foundation, Ministry of Education of Brazil, Brasilia - DF, Brazil
| | - Claudia Clopath
- Department of Bioengineering, Imperial College London, London, United Kingdom
| |
Collapse
|
46
|
Sanders H, Wilson MA, Gershman SJ. Hippocampal remapping as hidden state inference. eLife 2020; 9:51140. [PMID: 32515352 PMCID: PMC7282808 DOI: 10.7554/elife.51140] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 05/09/2020] [Indexed: 11/13/2022] Open
Abstract
Cells in the hippocampus tuned to spatial location (place cells) typically change their tuning when an animal changes context, a phenomenon known as remapping. A fundamental challenge to understanding remapping is the fact that what counts as a ‘‘context change’’ has never been precisely defined. Furthermore, different remapping phenomena have been classified on the basis of how much the tuning changes after different types and degrees of context change, but the relationship between these variables is not clear. We address these ambiguities by formalizing remapping in terms of hidden state inference. According to this view, remapping does not directly reflect objective, observable properties of the environment, but rather subjective beliefs about the hidden state of the environment. We show how the hidden state framework can resolve a number of puzzles about the nature of remapping.
Collapse
Affiliation(s)
- Honi Sanders
- Center for Brains Minds and Machines, Harvard University, Cambridge, United States.,Picower Institute for Learning and Memory and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
| | - Matthew A Wilson
- Center for Brains Minds and Machines, Harvard University, Cambridge, United States.,Picower Institute for Learning and Memory and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
| | - Samuel J Gershman
- Center for Brains Minds and Machines, Harvard University, Cambridge, United States.,Department of Psychology, Harvard University, Cambridge, United States
| |
Collapse
|
47
|
Tanaka KZ. Heterogeneous representations in the hippocampus. Neurosci Res 2020; 165:1-5. [PMID: 32445753 DOI: 10.1016/j.neures.2020.05.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Revised: 04/25/2020] [Accepted: 05/11/2020] [Indexed: 01/08/2023]
Abstract
The hippocampus is essential for some types of memory, but its specific role remains conjectural. While studies on place cells have supported the hypothesis that the hippocampus provides a spatial substrate for episodic memory, recent engram studies have shown that optogenetic activation of a subset of hippocampal neurons that lack a temporal structure of the spike sequences can also induce memory-associated behavior. In this short review, I discuss the various lines of research that have led to different views of the role of the hippocampus in memory and propose a plausible interpretation of the findings that incorporates two influential theories.
Collapse
Affiliation(s)
- Kazumasa Z Tanaka
- Okinawa Institute of Science and Technology Graduate University (OIST), Japan.
| |
Collapse
|
48
|
Morales L, Tomàs DP, Dalmau J, de la Rocha J, Jercog PE. High-Throughput Task to Study Memory Recall During Spatial Navigation in Rodents. Front Behav Neurosci 2020; 14:64. [PMID: 32499683 PMCID: PMC7243682 DOI: 10.3389/fnbeh.2020.00064] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Accepted: 04/06/2020] [Indexed: 12/04/2022] Open
Abstract
Spatial navigation is one of the most frequently used behavioral paradigms to study memory formation in rodents. Commonly used tasks to study memory are labor-intensive, preventing the simultaneous testing of multiple animals with the tendency to yield a low number of trials, curtailing the statistical power. Moreover, they are not tailored to be combined with neurophysiology recordings because they are not based on overt stereotyped behavioral responses that can be precisely timed. Here we present a novel task to study long-term memory formation and recall during spatial navigation. The task consists of learning sessions during which mice need to find the rewarding port that changes from day to day. Hours after learning, there is a recall session during which mice search for the location of the memorized rewarding port. During the recall sessions, the animals repeatedly poke the remembered port over many trials (up to ∼20) without receiving a reward (i.e., no positive feedback) as a readout of memory. In this task, mice show memory of port locations learned on up to three previous days. This eight-port maze task requires minimal human intervention, allowing for simultaneous and unsupervised testing of several mice in parallel, yielding a high number of recall trials per session over many days, and compatible with recordings of neural activity.
Collapse
Affiliation(s)
- Lucia Morales
- Institut d’Investigacions Biomèdiques August Pi i Sunyer, Barcelona, Spain
| | - David P. Tomàs
- Institut d’Investigacions Biomèdiques August Pi i Sunyer, Barcelona, Spain
| | - Josep Dalmau
- Institut d’Investigacions Biomèdiques August Pi i Sunyer, Barcelona, Spain
- Neuroimmunology Program, IDIBAPS-Hospital Clinic, Universitat de Barcelona, Barcelona, Spain
- Department of Neurology, University of Pennsylvania, Philadelphia, PA, United States
- Catalan Institution for Research and Advanced Studies, Barcelona, Spain
| | - Jaime de la Rocha
- Institut d’Investigacions Biomèdiques August Pi i Sunyer, Barcelona, Spain
| | - Pablo E. Jercog
- Institut d’Investigacions Biomèdiques August Pi i Sunyer, Barcelona, Spain
| |
Collapse
|
49
|
Assembly-Specific Disruption of Hippocampal Replay Leads to Selective Memory Deficit. Neuron 2020; 106:291-300.e6. [DOI: 10.1016/j.neuron.2020.01.021] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 11/13/2019] [Accepted: 01/16/2020] [Indexed: 01/14/2023]
|
50
|
Sheintuch L, Geva N, Baumer H, Rechavi Y, Rubin A, Ziv Y. Multiple Maps of the Same Spatial Context Can Stably Coexist in the Mouse Hippocampus. Curr Biol 2020; 30:1467-1476.e6. [PMID: 32220328 DOI: 10.1016/j.cub.2020.02.018] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 01/15/2020] [Accepted: 02/07/2020] [Indexed: 11/29/2022]
Abstract
Hippocampal place cells selectively fire when an animal traverses a particular location and are considered a neural substrate of spatial memory. Place cells were shown to change their activity patterns (remap) across different spatial contexts but to maintain their spatial tuning in a fixed familiar context. Here, we show that mouse hippocampal neurons can globally remap, forming multiple distinct representations (maps) of the same familiar environment, without any apparent changes in sensory input or behavior. Alternations between maps occurred only across separate visits to the environment, implying switching between distinct stable attractors in the hippocampal network. Importantly, the different maps were spatially informative and persistent over weeks, demonstrating that they can be reliably stored and retrieved from long-term memory. Taken together, our results suggest that a memory of a given spatial context could be associated with multiple distinct neuronal representations, rather than just one.
Collapse
Affiliation(s)
- Liron Sheintuch
- Department of Neurobiology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Nitzan Geva
- Department of Neurobiology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Hadas Baumer
- Department of Neurobiology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Yoav Rechavi
- Department of Neurobiology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Alon Rubin
- Department of Neurobiology, Weizmann Institute of Science, Rehovot 76100, Israel.
| | - Yaniv Ziv
- Department of Neurobiology, Weizmann Institute of Science, Rehovot 76100, Israel.
| |
Collapse
|