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Mizuta K, Sato M. Multiphoton imaging of hippocampal neural circuits: techniques and biological insights into region-, cell-type-, and pathway-specific functions. NEUROPHOTONICS 2024; 11:033406. [PMID: 38464393 PMCID: PMC10923542 DOI: 10.1117/1.nph.11.3.033406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 01/31/2024] [Accepted: 02/06/2024] [Indexed: 03/12/2024]
Abstract
Significance The function of the hippocampus in behavior and cognition has long been studied primarily through electrophysiological recordings from freely moving rodents. However, the application of optical recording methods, particularly multiphoton fluorescence microscopy, in the last decade or two has dramatically advanced our understanding of hippocampal function. This article provides a comprehensive overview of techniques and biological findings obtained from multiphoton imaging of hippocampal neural circuits. Aim This review aims to summarize and discuss the recent technical advances in multiphoton imaging of hippocampal neural circuits and the accumulated biological knowledge gained through this technology. Approach First, we provide a brief overview of various techniques of multiphoton imaging of the hippocampus and discuss its advantages, drawbacks, and associated key innovations and practices. Then, we review a large body of findings obtained through multiphoton imaging by region (CA1 and dentate gyrus), cell type (pyramidal neurons, inhibitory interneurons, and glial cells), and cellular compartment (dendrite and axon). Results Multiphoton imaging of the hippocampus is primarily performed under head-fixed conditions and can reveal detailed mechanisms of circuit operation owing to its high spatial resolution and specificity. As the hippocampus lies deep below the cortex, its imaging requires elaborate methods. These include imaging cannula implantation, microendoscopy, and the use of long-wavelength light sources. Although many studies have focused on the dorsal CA1 pyramidal cells, studies of other local and inter-areal circuitry elements have also helped provide a more comprehensive picture of the information processing performed by the hippocampal circuits. Imaging of circuit function in mouse models of Alzheimer's disease and other brain disorders such as autism spectrum disorder has also contributed greatly to our understanding of their pathophysiology. Conclusions Multiphoton imaging has revealed much regarding region-, cell-type-, and pathway-specific mechanisms in hippocampal function and dysfunction in health and disease. Future technological advances will allow further illustration of the operating principle of the hippocampal circuits via the large-scale, high-resolution, multimodal, and minimally invasive imaging.
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Affiliation(s)
- Kotaro Mizuta
- RIKEN BDR, Kobe, Japan
- New York University Abu Dhabi, Department of Biology, Abu Dhabi, United Arab Emirates
| | - Masaaki Sato
- Hokkaido University Graduate School of Medicine, Department of Neuropharmacology, Sapporo, Japan
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2
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Ghazinouri B, Nejad MM, Cheng S. Navigation and the efficiency of spatial coding: insights from closed-loop simulations. Brain Struct Funct 2024; 229:577-592. [PMID: 37029811 PMCID: PMC10978723 DOI: 10.1007/s00429-023-02637-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 03/28/2023] [Indexed: 04/09/2023]
Abstract
Spatial learning is critical for survival and its underlying neuronal mechanisms have been studied extensively. These studies have revealed a wealth of information about the neural representations of space, such as place cells and boundary cells. While many studies have focused on how these representations emerge in the brain, their functional role in driving spatial learning and navigation has received much less attention. We extended an existing computational modeling tool-chain to study the functional role of spatial representations using closed-loop simulations of spatial learning. At the heart of the model agent was a spiking neural network that formed a ring attractor. This network received inputs from place and boundary cells and the location of the activity bump in this network was the output. This output determined the movement directions of the agent. We found that the navigation performance depended on the parameters of the place cell input, such as their number, the place field sizes, and peak firing rate, as well as, unsurprisingly, the size of the goal zone. The dependence on the place cell parameters could be accounted for by just a single variable, the overlap index, but this dependence was nonmonotonic. By contrast, performance scaled monotonically with the Fisher information of the place cell population. Our results therefore demonstrate that efficiently encoding spatial information is critical for navigation performance.
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Affiliation(s)
- Behnam Ghazinouri
- Faculty of Computer Science, Institute for Neural Computation, Ruhr University Bochum, Universitätsstrasse 150, 44801, Bochum, Germany
| | - Mohammadreza Mohagheghi Nejad
- Faculty of Computer Science, Institute for Neural Computation, Ruhr University Bochum, Universitätsstrasse 150, 44801, Bochum, Germany
| | - Sen Cheng
- Faculty of Computer Science, Institute for Neural Computation, Ruhr University Bochum, Universitätsstrasse 150, 44801, Bochum, Germany.
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Secer G, Knierim JJ, Cowan NJ. Continuous Bump Attractor Networks Require Explicit Error Coding for Gain Recalibration. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.12.579874. [PMID: 38562699 PMCID: PMC10983875 DOI: 10.1101/2024.02.12.579874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Representations of continuous variables are crucial to create internal models of the external world. A prevailing model of how the brain maintains these representations is given by continuous bump attractor networks (CBANs) in a broad range of brain functions across different areas, such as spatial navigation in hippocampal/entorhinal circuits and working memory in prefrontal cortex. Through recurrent connections, a CBAN maintains a persistent activity bump, whose peak location can vary along a neural space, corresponding to different values of a continuous variable. To track the value of a continuous variable changing over time, a CBAN updates the location of its activity bump based on inputs that encode the changes in the continuous variable (e.g., movement velocity in the case of spatial navigation)-a process akin to mathematical integration. This integration process is not perfect and accumulates error over time. For error correction, CBANs can use additional inputs providing ground-truth information about the continuous variable's correct value (e.g., visual landmarks for spatial navigation). These inputs enable the network dynamics to automatically correct any representation error. Recent experimental work on hippocampal place cells has shown that, beyond correcting errors, ground-truth inputs also fine-tune the gain of the integration process, a crucial factor that links the change in the continuous variable to the updating of the activity bump's location. However, existing CBAN models lack this plasticity, offering no insights into the neural mechanisms and representations involved in the recalibration of the integration gain. In this paper, we explore this gap by using a ring attractor network, a specific type of CBAN, to model the experimental conditions that demonstrated gain recalibration in hippocampal place cells. Our analysis reveals the necessary conditions for neural mechanisms behind gain recalibration within a CBAN. Unlike error correction, which occurs through network dynamics based on ground-truth inputs, gain recalibration requires an additional neural signal that explicitly encodes the error in the network's representation via a rate code. Finally, we propose a modified ring attractor network as an example CBAN model that verifies our theoretical findings. Combining an error-rate code with Hebbian synaptic plasticity, this model achieves recalibration of integration gain in a CBAN, ensuring accurate representation for continuous variables.
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Affiliation(s)
- Gorkem Secer
- Laboratory for Computational Sensing and Robotics, Johns Hopkins University, Baltimore, MD 21218, USA
- Zanvyl Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, MD 21218, USA
| | - James J Knierim
- Zanvyl Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, MD 21218, USA
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Kavli Neuroscience Discovery Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Noah J Cowan
- Laboratory for Computational Sensing and Robotics, Johns Hopkins University, Baltimore, MD 21218, USA
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
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4
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Severino L, Kim J, Nam MH, McHugh TJ. From synapses to circuits: What mouse models have taught us about how autism spectrum disorder impacts hippocampal function. Neurosci Biobehav Rev 2024; 158:105559. [PMID: 38246230 DOI: 10.1016/j.neubiorev.2024.105559] [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: 11/29/2023] [Revised: 01/16/2024] [Accepted: 01/17/2024] [Indexed: 01/23/2024]
Abstract
Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder that impacts a variety of cognitive and behavioral domains. While a genetic component of ASD has been well-established, none of the numerous syndromic genes identified in humans accounts for more than 1% of the clinical patients. Due to this large number of target genes, numerous mouse models of the disorder have been generated. However, the focus on distinct brain circuits, behavioral phenotypes and diverse experimental approaches has made it difficult to synthesize the overwhelming number of model animal studies into concrete throughlines that connect the data across levels of investigation. Here we chose to focus on one circuit, the hippocampus, and one hypothesis, a shift in excitatory/inhibitory balance, to examine, from the level of the tripartite synapse up to the level of in vivo circuit activity, the key commonalities across disparate models that can illustrate a path towards a better mechanistic understanding of ASD's impact on hippocampal circuit function.
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Affiliation(s)
- Leandra Severino
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, South Korea; Division of Bio-Medical Science & Technology, KIST-School, University of Science and Technology, Seoul, South Korea
| | - Jinhyun Kim
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, South Korea; Division of Bio-Medical Science & Technology, KIST-School, University of Science and Technology, Seoul, South Korea
| | - Min-Ho Nam
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, South Korea; Division of Bio-Medical Science & Technology, KIST-School, University of Science and Technology, Seoul, South Korea.
| | - Thomas J McHugh
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, South Korea; Laboratory for Circuit and Behavioral Physiology, RIKEN Center for Brain Science, 2-1 Hirosawa, Wako-shi Saitama, Japan.
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5
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Sosa M, Plitt MH, Giocomo LM. Hippocampal sequences span experience relative to rewards. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.12.27.573490. [PMID: 38234842 PMCID: PMC10793396 DOI: 10.1101/2023.12.27.573490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
Hippocampal place cells fire in sequences that span spatial environments and non-spatial modalities, suggesting that hippocampal activity can anchor to the most behaviorally salient aspects of experience. As reward is a highly salient event, we hypothesized that sequences of hippocampal activity can anchor to rewards. To test this, we performed two-photon imaging of hippocampal CA1 neurons as mice navigated virtual environments with changing hidden reward locations. When the reward moved, the firing fields of a subpopulation of cells moved to the same relative position with respect to reward, constructing a sequence of reward-relative cells that spanned the entire task structure. The density of these reward-relative sequences increased with task experience as additional neurons were recruited to the reward-relative population. Conversely, a largely separate subpopulation maintained a spatially-based place code. These findings thus reveal separate hippocampal ensembles can flexibly encode multiple behaviorally salient reference frames, reflecting the structure of the experience.
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Affiliation(s)
- Marielena Sosa
- Department of Neurobiology, Stanford University School of Medicine; Stanford, CA, USA
| | - Mark H. Plitt
- Department of Neurobiology, Stanford University School of Medicine; Stanford, CA, USA
- Present address: Department of Molecular and Cell Biology, University of California Berkeley; Berkeley, CA, USA
| | - Lisa M. Giocomo
- Department of Neurobiology, Stanford University School of Medicine; Stanford, CA, USA
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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.
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Gianatti M, Garvert AC, Lenkey N, Ebbesen NC, Hennestad E, Vervaeke K. Multiple long-range projections convey position information to the agranular retrosplenial cortex. Cell Rep 2023; 42:113109. [PMID: 37682706 DOI: 10.1016/j.celrep.2023.113109] [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: 09/21/2022] [Revised: 06/13/2023] [Accepted: 08/23/2023] [Indexed: 09/10/2023] Open
Abstract
Neuronal signals encoding the animal's position widely modulate neocortical processing. While these signals are assumed to depend on hippocampal output, their origin has not been investigated directly. Here, we asked which brain region sends position information to the retrosplenial cortex (RSC), a key circuit for memory and navigation. We comprehensively characterized the long-range inputs to agranular RSC using two-photon axonal imaging in head-fixed mice performing a spatial task in darkness. Surprisingly, most long-range pathways convey position information, but with notable differences. Axons from the secondary motor and posterior parietal cortex transmit the most position information. By contrast, axons from the anterior cingulate and orbitofrontal cortex and thalamus convey substantially less position information. Axons from the primary and secondary visual cortex contribute negligibly. This demonstrates that the hippocampus is not the only source of position information. Instead, the RSC is a hub in a distributed brain network that shares position information.
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Affiliation(s)
- Michele Gianatti
- Institute of Basic Medical Sciences, Section of Physiology, University of Oslo, Oslo, Norway
| | - Anna Christina Garvert
- Institute of Basic Medical Sciences, Section of Physiology, University of Oslo, Oslo, Norway
| | - Nora Lenkey
- Institute of Basic Medical Sciences, Section of Physiology, University of Oslo, Oslo, Norway
| | - Nora Cecilie Ebbesen
- Institute of Basic Medical Sciences, Section of Physiology, University of Oslo, Oslo, Norway
| | - Eivind Hennestad
- Institute of Basic Medical Sciences, Section of Physiology, University of Oslo, Oslo, Norway
| | - Koen Vervaeke
- Institute of Basic Medical Sciences, Section of Physiology, University of Oslo, Oslo, Norway.
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8
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Michon FX, Laplante I, Bosson A, Robitaille R, Lacaille JC. mTORC1-mediated acquisition of reward-related representations by hippocampal somatostatin interneurons. Mol Brain 2023; 16:55. [PMID: 37400913 DOI: 10.1186/s13041-023-01042-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 06/03/2023] [Indexed: 07/05/2023] Open
Abstract
Plasticity of principal cells and inhibitory interneurons underlies hippocampal memory. Bidirectional modulation of somatostatin cell mTORC1 activity, a crucial translational control mechanism in synaptic plasticity, causes parallel changes in hippocampal CA1 somatostatin interneuron (SOM-IN) long-term potentiation and hippocampus-dependent memory, indicating a key role in learning. However, SOM-IN activity changes and behavioral correlates during learning, and the role of mTORC1 in these processes, remain ill-defined. To address these questions, we used two-photon Ca2+ imaging from SOM-INs during a virtual reality goal-directed spatial memory task in head-fixed control mice (SOM-IRES-Cre mice) or in mice with conditional knockout of Rptor (SOM-Rptor-KO mice) to block mTORC1 activity in SOM-INs. We found that control mice learn the task, but SOM-Raptor-KO mice exhibit a deficit. Also, SOM-IN Ca2+ activity became increasingly related to reward during learning in control mice but not in SOM-Rptor-KO mice. Four types of SOM-IN activity patterns related to reward location were observed, "reward off sustained", "reward off transient", "reward on sustained" and "reward on transient", and these responses showed reorganization after reward relocation in control but not SOM-Rptor-KO mice. Thus, SOM-INs develop mTORC1-dependent reward- related activity during learning. This coding may bi-directionally interact with pyramidal cells and other structures to represent and consolidate reward location.
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Affiliation(s)
- François-Xavier Michon
- Department of Neurosciences, Center for Interdisciplinary Research on Brain and Learning (CIRCA) and Research Group on Neural Signaling and Circuitry (GRSNC), Université de Montréal, Montreal, QC, H3C 3J7, Canada
| | - Isabel Laplante
- Department of Neurosciences, Center for Interdisciplinary Research on Brain and Learning (CIRCA) and Research Group on Neural Signaling and Circuitry (GRSNC), Université de Montréal, Montreal, QC, H3C 3J7, Canada
| | - Anthony Bosson
- Department of Neurosciences, Center for Interdisciplinary Research on Brain and Learning (CIRCA) and Research Group on Neural Signaling and Circuitry (GRSNC), Université de Montréal, Montreal, QC, H3C 3J7, Canada
| | - Richard Robitaille
- Department of Neurosciences, Center for Interdisciplinary Research on Brain and Learning (CIRCA) and Research Group on Neural Signaling and Circuitry (GRSNC), Université de Montréal, Montreal, QC, H3C 3J7, Canada
| | - Jean-Claude Lacaille
- Department of Neurosciences, Center for Interdisciplinary Research on Brain and Learning (CIRCA) and Research Group on Neural Signaling and Circuitry (GRSNC), Université de Montréal, Montreal, QC, H3C 3J7, Canada.
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9
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Parra-Barrero E, Cheng S. Learning to predict future locations with internally generated theta sequences. PLoS Comput Biol 2023; 19:e1011101. [PMID: 37172053 DOI: 10.1371/journal.pcbi.1011101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 05/24/2023] [Accepted: 04/13/2023] [Indexed: 05/14/2023] Open
Abstract
Representing past, present and future locations is key for spatial navigation. Indeed, within each cycle of the theta oscillation, the population of hippocampal place cells appears to represent trajectories starting behind the current position of the animal and sweeping ahead of it. In particular, we reported recently that the position represented by CA1 place cells at a given theta phase corresponds to the location where animals were or will be located at a fixed time interval into the past or future assuming the animal ran at its typical, not the current, speed through that part of the environment. This coding scheme leads to longer theta trajectories, larger place fields and shallower phase precession in areas where animals typically run faster. Here we present a mechanistic computational model that accounts for these experimental observations. The model consists of a continuous attractor network with short-term synaptic facilitation and depression that internally generates theta sequences that advance at a fixed pace. Spatial locations are then mapped onto the active units via modified Hebbian plasticity. As a result, neighboring units become associated with spatial locations further apart where animals run faster, reproducing our earlier experimental results. The model also accounts for the higher density of place fields generally observed where animals slow down, such as around rewards. Furthermore, our modeling results reveal that an artifact of the decoding analysis might be partly responsible for the observation that theta trajectories start behind the animal's current position. Overall, our results shed light on how the hippocampal code might arise from the interplay between behavior, sensory input and predefined network dynamics.
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Affiliation(s)
- Eloy Parra-Barrero
- Institute for Neural Computation, Faculty of Computer Science, Ruhr University Bochum, Bochum, Germany
- International Graduate School of Neuroscience, Ruhr University Bochum, Bochum, Germany
| | - Sen Cheng
- Institute for Neural Computation, Faculty of Computer Science, Ruhr University Bochum, Bochum, Germany
- International Graduate School of Neuroscience, Ruhr University Bochum, Bochum, Germany
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10
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Kong E, Lee KH, Do J, Kim P, Lee D. Dynamic and stable hippocampal representations of social identity and reward expectation support associative social memory in male mice. Nat Commun 2023; 14:2597. [PMID: 37147388 PMCID: PMC10163237 DOI: 10.1038/s41467-023-38338-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 04/26/2023] [Indexed: 05/07/2023] Open
Abstract
Recognizing an individual and retrieving and updating the value information assigned to the individual are fundamental abilities for establishing social relationships. To understand the neural mechanisms underlying the association between social identity and reward value, we developed Go-NoGo social discrimination paradigms that required male subject mice to distinguish between familiar mice based on their individually unique characteristics and associate them with reward availability. We found that mice could discriminate individual conspecifics through a brief nose-to-nose investigation, and this ability depended on the dorsal hippocampus. Two-photon calcium imaging revealed that dorsal CA1 hippocampal neurons represented reward expectation during social, but not non-social tasks, and these activities were maintained over days regardless of the identity of the associated mouse. Furthermore, a dynamically changing subset of hippocampal CA1 neurons discriminated between individual mice with high accuracy. Our findings suggest that the neuronal activities in CA1 provide possible neural substrates for associative social memory.
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Affiliation(s)
- Eunji Kong
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon, 34126, Republic of Korea
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
- KI for Health Science and Technology (KIHST), Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Kyu-Hee Lee
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon, 34126, Republic of Korea
| | - Jongrok Do
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon, 34126, Republic of Korea
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Pilhan Kim
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea.
- KI for Health Science and Technology (KIHST), Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea.
| | - Doyun Lee
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon, 34126, Republic of Korea.
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Biane JS, Ladow MA, Stefanini F, Boddu SP, Fan A, Hassan S, Dundar N, Apodaca-Montano DL, Zhou LZ, Fayner V, Woods NI, Kheirbek MA. Neural dynamics underlying associative learning in the dorsal and ventral hippocampus. Nat Neurosci 2023; 26:798-809. [PMID: 37012382 PMCID: PMC10448873 DOI: 10.1038/s41593-023-01296-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 03/07/2023] [Indexed: 04/05/2023]
Abstract
Animals associate cues with outcomes and update these associations as new information is presented. This requires the hippocampus, yet how hippocampal neurons track changes in cue-outcome associations remains unclear. Using two-photon calcium imaging, we tracked the same dCA1 and vCA1 neurons across days to determine how responses evolve across phases of odor-outcome learning. Initially, odors elicited robust responses in dCA1, whereas, in vCA1, odor responses primarily emerged after learning and embedded information about the paired outcome. Population activity in both regions rapidly reorganized with learning and then stabilized, storing learned odor representations for days, even after extinction or pairing with a different outcome. Additionally, we found stable, robust signals across CA1 when mice anticipated outcomes under behavioral control but not when mice anticipated an inescapable aversive outcome. These results show how the hippocampus encodes, stores and updates learned associations and illuminates the unique contributions of dorsal and ventral hippocampus.
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Affiliation(s)
- Jeremy S Biane
- Department of Psychiatry and Behavioral Sciences, University of California, San Francisco, San Francisco, CA, USA.
| | - Max A Ladow
- Neuroscience Graduate Program, University of California, San Francisco, San Francisco, CA, USA
| | - Fabio Stefanini
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Department of Neuroscience, Columbia University, New York, NY, USA
| | - Sayi P Boddu
- Department of Psychiatry and Behavioral Sciences, University of California, San Francisco, San Francisco, CA, USA
| | - Austin Fan
- Department of Psychiatry and Behavioral Sciences, University of California, San Francisco, San Francisco, CA, USA
| | - Shazreh Hassan
- Department of Psychiatry and Behavioral Sciences, University of California, San Francisco, San Francisco, CA, USA
| | - Naz Dundar
- Department of Psychiatry and Behavioral Sciences, University of California, San Francisco, San Francisco, CA, USA
- Neuroscience Graduate Program, University of California, San Francisco, San Francisco, CA, USA
| | - Daniel L Apodaca-Montano
- Department of Psychiatry and Behavioral Sciences, University of California, San Francisco, San Francisco, CA, USA
| | - Lexi Zichen Zhou
- Department of Psychiatry and Behavioral Sciences, University of California, San Francisco, San Francisco, CA, USA
| | - Varya Fayner
- Department of Psychiatry and Behavioral Sciences, University of California, San Francisco, San Francisco, CA, USA
| | - Nicholas I Woods
- Neuroscience Graduate Program, University of California, San Francisco, San Francisco, CA, USA
| | - Mazen A Kheirbek
- Department of Psychiatry and Behavioral Sciences, University of California, San Francisco, San Francisco, CA, USA.
- Neuroscience Graduate Program, University of California, San Francisco, San Francisco, CA, USA.
- Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, CA, USA.
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA.
- Center for Integrative Neuroscience, University of California, San Francisco, San Francisco, CA, USA.
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Nakai N, Sato M, Yamashita O, Sekine Y, Fu X, Nakai J, Zalesky A, Takumi T. Virtual reality-based real-time imaging reveals abnormal cortical dynamics during behavioral transitions in a mouse model of autism. Cell Rep 2023; 42:112258. [PMID: 36990094 DOI: 10.1016/j.celrep.2023.112258] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 02/16/2023] [Accepted: 02/28/2023] [Indexed: 03/30/2023] Open
Abstract
Functional connectivity (FC) can provide insight into cortical circuit dysfunction in neuropsychiatric disorders. However, dynamic changes in FC related to locomotion with sensory feedback remain to be elucidated. To investigate FC dynamics in locomoting mice, we develop mesoscopic Ca2+ imaging with a virtual reality (VR) environment. We find rapid reorganization of cortical FC in response to changing behavioral states. By using machine learning classification, behavioral states are accurately decoded. We then use our VR-based imaging system to study cortical FC in a mouse model of autism and find that locomotion states are associated with altered FC dynamics. Furthermore, we identify FC patterns involving the motor area as the most distinguishing features of the autism mice from wild-type mice during behavioral transitions, which might correlate with motor clumsiness in individuals with autism. Our VR-based real-time imaging system provides crucial information to understand FC dynamics linked to behavioral abnormality of neuropsychiatric disorders.
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Affiliation(s)
- Nobuhiro Nakai
- RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan; Department of Physiology and Cell Biology, Kobe University School of Medicine, Chuo, Kobe 650-0017, Japan
| | - Masaaki Sato
- RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan; Department of Neuropharmacology, Hokkaido University Graduate School of Medicine, Kita, Sapporo 060-8638, Japan.
| | - Okito Yamashita
- RIKEN Center for Advanced Intelligence Project, Chuo, Tokyo 103-0027, Japan; Department of Computational Brain Imaging, ATR Neural Information Analysis Laboratories, Seika, Kyoto 619-0288, Japan
| | - Yukiko Sekine
- RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan
| | - Xiaochen Fu
- RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan
| | - Junichi Nakai
- Division of Oral Physiology, Department of Disease Management Dentistry, Tohoku University Graduate School of Dentistry, Aoba, Sendai 980-8575, Japan
| | - Andrew Zalesky
- Melbourne Neuropsychiatry Centre and Department of Biomedical Engineering, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - Toru Takumi
- RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan; Department of Physiology and Cell Biology, Kobe University School of Medicine, Chuo, Kobe 650-0017, Japan; RIKEN Center for Biosystems Dynamics Research, Chuo, Kobe 650-0047, Japan.
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13
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Corrigan BW, Gulli RA, Doucet G, Mahmoudian B, Abbass M, Roussy M, Luna R, Sachs AJ, Martinez‐Trujillo JC. View cells in the hippocampus and prefrontal cortex of macaques during virtual navigation. Hippocampus 2023; 33:573-585. [PMID: 37002559 DOI: 10.1002/hipo.23534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 03/17/2023] [Accepted: 03/21/2023] [Indexed: 04/03/2023]
Abstract
Cells selectively activated by a particular view of an environment have been found in the primate hippocampus (HPC). Whether view cells are present in other brain areas, and how view selectivity interacts with other variables such as object features and place remain unclear. Here, we explore these issues by recording the responses of neurons in the HPC and the lateral prefrontal cortex (LPFC) of rhesus macaques performing a task in which they learn new context-object associations while navigating a virtual environment using a joystick. We measured neuronal responses at different locations in a virtual maze where animals freely directed gaze to different regions of the visual scenes. We show that specific views containing task relevant objects selectively activated a proportion of HPC units, and an even higher proportion of LPFC units. Place selectivity was scarce and generally dependent on view. Many view cells were not affected by changing the object color or the context cue, two task relevant features. However, a small proportion of view cells showed selectivity for these two features. Our results show that during navigation in a virtual environment with complex and dynamic visual stimuli, view cells are found in both the HPC and the LPFC. View cells may have developed as a multiarea specialization in diurnal primates to encode the complexities and layouts of the environment through gaze exploration which ultimately enables building cognitive maps of space that guide navigation.
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Affiliation(s)
- Benjamin W. Corrigan
- Department of Physiology and Pharmacology University of Western Ontario London Ontario Canada
| | - Roberto A. Gulli
- Zuckerman Mind Brain Behavior Institute Columbia University New York New York USA
- Center for Theoretical Neuroscience Columbia University New York New York USA
| | - Guillaume Doucet
- The Ottawa Hospital University of Ottawa Ottawa Ontario Canada
- Realize Medical Ottawa Ontario Canada
| | - Borna Mahmoudian
- Department of Physiology and Pharmacology University of Western Ontario London Ontario Canada
| | - Mohamad Abbass
- Western University Department of Clinical Neurological Sciences, London Health Sciences Centre Western University London Ontario Canada
| | - Megan Roussy
- Department of Physiology and Pharmacology University of Western Ontario London Ontario Canada
- National Science and Engineering Research Council Ottawa Ontario Canada
| | - Rogelio Luna
- Department of Physiology and Pharmacology University of Western Ontario London Ontario Canada
- Facultad de Medicina y Ciencias Biomédicas Universidad Autónoma de Chihuahua Chihuahua City Mexico
| | - Adam J. Sachs
- The Ottawa Hospital University of Ottawa Ottawa Ontario Canada
| | - Julio C. Martinez‐Trujillo
- Department of Physiology and Pharmacology University of Western Ontario London Ontario Canada
- Department of Psychiatry, Schulich School of Medicine and Dentistry University of Western Ontario London Ontario Canada
- Western Institute for Neuroscience University of Western Ontario London Ontario Canada
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14
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Yoo YE, Yoo T, Kang H, Kim E. Brain region and gene dosage-differential transcriptomic changes in Shank2-mutant mice. Front Mol Neurosci 2022; 15:977305. [PMID: 36311025 PMCID: PMC9612946 DOI: 10.3389/fnmol.2022.977305] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 09/16/2022] [Indexed: 12/20/2022] Open
Abstract
Shank2 is an abundant excitatory postsynaptic scaffolding protein that has been implicated in various neurodevelopmental and psychiatric disorders, including autism spectrum disorder (ASD), intellectual disability, attention-deficit/hyperactivity disorder, and schizophrenia. Shank2-mutant mice show ASD-like behavioral deficits and altered synaptic and neuronal functions, but little is known about how different brain regions and gene dosages affect the transcriptomic phenotypes of these mice. Here, we performed RNA-Seq-based transcriptomic analyses of the prefrontal cortex, hippocampus, and striatum in adult Shank2 heterozygous (HT)- and homozygous (HM)-mutant mice lacking exons 6–7. The prefrontal cortical, hippocampal, and striatal regions showed distinct transcriptomic patterns associated with synapse, ribosome, mitochondria, spliceosome, and extracellular matrix (ECM). The three brain regions were also distinct in the expression of ASD-related and ASD-risk genes. These differential patterns were stronger in the prefrontal cortex where the HT transcriptome displayed increased synaptic gene expression and reverse-ASD patterns whereas the HM transcriptome showed decreased synaptic gene expression and ASD-like patterns. These results suggest brain region- and gene dosage-differential transcriptomic changes in Shank2-mutant mice.
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Affiliation(s)
- Ye-Eun Yoo
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, South Korea
| | - Taesun Yoo
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, South Korea
| | - Hyojin Kang
- Division of National Supercomputing, Korea Institute of Science and Technology Information (KISTI), Daejeon, South Korea
| | - Eunjoon Kim
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, South Korea
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, South Korea
- *Correspondence: Eunjoon Kim,
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15
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Abstract
Astrocytic calcium dynamics has been implicated in the encoding of sensory information1-5, and modulation of calcium in astrocytes has been shown to affect behaviour6-10. However, longitudinal investigation of the real-time calcium activity of astrocytes in the hippocampus of awake mice is lacking. Here we used two-photon microscopy to chronically image CA1 astrocytes as mice ran in familiar or new virtual environments to obtain water rewards. We found that astrocytes exhibit persistent ramping activity towards the reward location in a familiar environment, but not in a new one. Shifting the reward location within a familiar environment also resulted in diminished ramping. After additional training, as the mice became familiar with the new context or new reward location, the ramping was re-established. Using linear decoders, we could predict the location of the mouse in a familiar environment from astrocyte activity alone. We could not do the same in a new environment, suggesting that the spatial modulation of astrocytic activity is experience dependent. Our results indicate that astrocytes can encode the expected reward location in spatial contexts, thereby extending their known computational abilities and their role in cognitive functions.
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16
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Pfeiffer BE. Spatial Learning Drives Rapid Goal Representation in Hippocampal Ripples without Place Field Accumulation or Goal-Oriented Theta Sequences. J Neurosci 2022; 42:3975-3988. [PMID: 35396328 PMCID: PMC9097771 DOI: 10.1523/jneurosci.2479-21.2022] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 03/28/2022] [Accepted: 03/30/2022] [Indexed: 01/05/2023] Open
Abstract
The hippocampus is critical for rapid acquisition of many forms of memory, although the circuit-level mechanisms through which the hippocampus rapidly consolidates novel information are unknown. Here, the activity of large ensembles of hippocampal neurons in adult male Long-Evans rats was monitored across a period of rapid spatial learning to assess how the network changes during the initial phases of memory formation and retrieval. In contrast to several reports, the hippocampal network did not display enhanced representation of the goal location via accumulation of place fields or elevated firing rates at the goal. Rather, population activity rates increased globally as a function of experience. These alterations in activity were mirrored in the power of the theta oscillation and in the quality of theta sequences, without preferential encoding of paths to the learned goal location. In contrast, during brief "offline" pauses in movement, representation of a novel goal location emerged rapidly in ripples, preceding other changes in network activity. These data demonstrate that the hippocampal network can facilitate active navigation without enhanced goal representation during periods of active movement, and further indicate that goal representation in hippocampal ripples before movement onset supports subsequent navigation, possibly through activation of downstream cortical networks.SIGNIFICANCE STATEMENT Understanding the mechanisms through which the networks of the brain rapidly assimilate information and use previously learned knowledge are fundamental areas of focus in neuroscience. In particular, the hippocampal circuit is a critical region for rapid formation and use of spatial memory. In this study, several circuit-level features of hippocampal function were quantified while rats performed a spatial navigation task requiring rapid memory formation and use. During periods of active navigation, a general increase in overall network activity is observed during memory acquisition, which plateaus during memory retrieval periods, without specific enhanced representation of the goal location. During pauses in navigation, rapid representation of the distant goal well emerges before either behavioral improvement or changes in online activity.
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Affiliation(s)
- Brad E Pfeiffer
- Neuroscience Graduate Program, Department of Neuroscience, Peter O'Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, Texas 75390
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17
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The shallow cognitive map hypothesis: A hippocampal framework for thought disorder in schizophrenia. SCHIZOPHRENIA (HEIDELBERG, GERMANY) 2022; 8:34. [PMID: 35853896 PMCID: PMC9261089 DOI: 10.1038/s41537-022-00247-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 03/11/2022] [Indexed: 12/31/2022]
Abstract
Memories are not formed in isolation. They are associated and organized into relational knowledge structures that allow coherent thought. Failure to express such coherent thought is a key hallmark of Schizophrenia. Here we explore the hypothesis that thought disorder arises from disorganized Hippocampal cognitive maps. In doing so, we combine insights from two key lines of investigation, one concerning the neural signatures of cognitive mapping, and another that seeks to understand lower-level cellular mechanisms of cognition within a dynamical systems framework. Specifically, we propose that multiple distinct pathological pathways converge on the shallowing of Hippocampal attractors, giving rise to disorganized Hippocampal cognitive maps and driving conceptual disorganization. We discuss the available evidence at the computational, behavioural, network, and cellular levels. We also outline testable predictions from this framework, including how it could unify major chemical and psychological theories of schizophrenia and how it can provide a rationale for understanding the aetiology and treatment of the disease.
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18
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Nyberg N, Duvelle É, Barry C, Spiers HJ. Spatial goal coding in the hippocampal formation. Neuron 2022; 110:394-422. [PMID: 35032426 DOI: 10.1016/j.neuron.2021.12.012] [Citation(s) in RCA: 42] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 10/18/2021] [Accepted: 12/08/2021] [Indexed: 12/22/2022]
Abstract
The mammalian hippocampal formation contains several distinct populations of neurons involved in representing self-position and orientation. These neurons, which include place, grid, head direction, and boundary-vector cells, are thought to collectively instantiate cognitive maps supporting flexible navigation. However, to flexibly navigate, it is necessary to also maintain internal representations of goal locations, such that goal-directed routes can be planned and executed. Although it has remained unclear how the mammalian brain represents goal locations, multiple neural candidates have recently been uncovered during different phases of navigation. For example, during planning, sequential activation of spatial cells may enable simulation of future routes toward the goal. During travel, modulation of spatial cells by the prospective route, or by distance and direction to the goal, may allow maintenance of route and goal-location information, supporting navigation on an ongoing basis. As the goal is approached, an increased activation of spatial cells may enable the goal location to become distinctly represented within cognitive maps, aiding goal localization. Lastly, after arrival at the goal, sequential activation of spatial cells may represent the just-taken route, enabling route learning and evaluation. Here, we review and synthesize these and other evidence for goal coding in mammalian brains, relate the experimental findings to predictions from computational models, and discuss outstanding questions and future challenges.
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Affiliation(s)
- Nils Nyberg
- Institute of Behavioural Neuroscience, Department of Experimental Psychology, University College London, London, UK.
| | - Éléonore Duvelle
- Department of Psychological and Brain Sciences, Dartmouth College, Hanover, NH, USA
| | - Caswell Barry
- Department of Cell and Developmental Biology, University College London, London, UK
| | - Hugo J Spiers
- Institute of Behavioural Neuroscience, Department of Experimental Psychology, University College London, London, UK.
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19
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Different encoding of reward location in dorsal and intermediate hippocampus. Curr Biol 2022; 32:834-841.e5. [PMID: 35016008 DOI: 10.1016/j.cub.2021.12.024] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 11/05/2021] [Accepted: 12/08/2021] [Indexed: 01/29/2023]
Abstract
Hippocampal place cells fire at specific locations in the environment. They form a cognitive map that encodes spatial relations in the environment, including reward locations.1 As part of this encoding, dorsal CA1 (dCA1) place cells accumulate at reward.2-5 The encoding of learned reward location could vary between the dorsal and intermediate hippocampus, which differ in gene expression and cortical and subcortical connectivity.6 While the dorsal hippocampus is critical for spatial navigation, the involvement of intermediate CA1 (iCA1) in spatial navigation might depend on task complexity7 and learning phase.8-10 The intermediate-to-ventral hippocampus regulates reward-seeking,11-15 but little is known about the involvement in reward-directed navigation. Here, we compared the encoding of learned reward locations in dCA1 and iCA1 during spatial navigation. We used calcium imaging with a head-mounted microscope to track the activity of CA1 cells over multiple days during which mice learned different reward locations. In dCA1, the fraction of active place cells increased in anticipation of reward, but the pool of active cells changed with the reward location. In iCA1, the same cells anticipated multiple reward locations. Our results support a model in which the dCA1 cognitive map incorporates a changing population of cells that encodes reward proximity through increased population activity, while iCA1 provides a reward-predictive code through a dedicated subpopulation. Both of these location-invariant codes persisted over time, and together they provide a dual hippocampal reward location code, assisting goal-directed navigation.16,17.
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20
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Zhao X, Hsu CL, Spruston N. Rapid synaptic plasticity contributes to a learned conjunctive code of position and choice-related information in the hippocampus. Neuron 2021; 110:96-108.e4. [PMID: 34678146 DOI: 10.1016/j.neuron.2021.10.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/30/2021] [Accepted: 10/01/2021] [Indexed: 01/04/2023]
Abstract
To successfully perform goal-directed navigation, animals must know where they are and what they are doing-e.g., looking for water, bringing food back to the nest, or escaping from a predator. Hippocampal neurons code for these critical variables conjunctively, but little is known about how this "where/what" code is formed or flexibly routed to other brain regions. To address these questions, we performed intracellular whole-cell recordings in mouse CA1 during a cued, two-choice virtual navigation task. We demonstrate that plateau potentials in CA1 pyramidal neurons rapidly strengthen synaptic inputs carrying conjunctive information about position and choice. Plasticity-induced response fields were modulated by cues only in animals previously trained to collect rewards based on available cues. Thus, we reveal that gradual learning is required for the formation of a conjunctive population code, upstream of CA1, while plateau-potential-induced synaptic plasticity in CA1 enables flexible routing of the code to downstream brain regions.
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Affiliation(s)
- Xinyu Zhao
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Ching-Lung Hsu
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Nelson Spruston
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA.
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21
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Divergence in Population Coding for Space between Dorsal and Ventral CA1. eNeuro 2021; 8:ENEURO.0211-21.2021. [PMID: 34433573 PMCID: PMC8425966 DOI: 10.1523/eneuro.0211-21.2021] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 08/16/2021] [Accepted: 08/18/2021] [Indexed: 11/25/2022] Open
Abstract
Molecular, anatomic, and behavioral studies show that the hippocampus is structurally and functionally heterogeneous, with dorsal hippocampus implicated in mnemonic processes and spatial navigation and ventral hippocampus involved in affective processes. By performing electrophysiological recordings of large neuronal populations in dorsal and ventral CA1 in head-fixed mice navigating a virtual environment, we found that this diversity resulted in different strategies for population coding of space. Populations of neurons in dorsal CA1 showed more complex patterns of activity, which resulted in a higher dimensionality of neural representations that translated to more information being encoded, as compared ensembles in vCA1. Furthermore, a pairwise maximum entropy model was better at predicting the structure of these global patterns of activity in ventral CA1 as compared with dorsal CA1. Taken together, the different coding strategies we uncovered likely emerge from anatomic and physiological differences along the longitudinal axis of hippocampus and that may, in turn, underpin the divergent ethological roles of dorsal and ventral CA1.
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22
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Haga T, Fukai T. Multiscale representations of community structures in attractor neural networks. PLoS Comput Biol 2021; 17:e1009296. [PMID: 34424901 PMCID: PMC8412329 DOI: 10.1371/journal.pcbi.1009296] [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: 03/08/2021] [Revised: 09/02/2021] [Accepted: 07/21/2021] [Indexed: 11/19/2022] Open
Abstract
Our cognition relies on the ability of the brain to segment hierarchically structured events on multiple scales. Recent evidence suggests that the brain performs this event segmentation based on the structure of state-transition graphs behind sequential experiences. However, the underlying circuit mechanisms are poorly understood. In this paper we propose an extended attractor network model for graph-based hierarchical computation which we call the Laplacian associative memory. This model generates multiscale representations for communities (clusters) of associative links between memory items, and the scale is regulated by the heterogenous modulation of inhibitory circuits. We analytically and numerically show that these representations correspond to graph Laplacian eigenvectors, a popular method for graph segmentation and dimensionality reduction. Finally, we demonstrate that our model exhibits chunked sequential activity patterns resembling hippocampal theta sequences. Our model connects graph theory and attractor dynamics to provide a biologically plausible mechanism for abstraction in the brain. Our experiences are often hierarchically organized, so is our knowledge. Identifying meaningful segments in hierarchically structured information is crucial for many cognitive functions including visual, auditory, motor, memory, language processing, and reasoning. Herein, we show that the attractor dynamics of recurrent neural circuits offer a biologically plausible way for hierarchical segmentation. We found that an extended model of associative memory autonomously performs segmentation by finding groups of tightly linked memories. We proved that the neural dynamics of our model mathematically coincide with optimal graph segmentation in graph theory and are consistent with the experimentally observed nature of human behaviors and neural activities. Our model established a previously unexpected relationship between attractor neural networks and the graph-theoretic processing of knowledge structures. Our model also provides experimentally testable predictions, particularly regarding the role of inhibitory circuits in controlling representational granularity.
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Affiliation(s)
- Tatsuya Haga
- Okinawa Institute of Science and Technology, Onna-son, Okinawa, Japan
- * E-mail: (TH); (TF)
| | - Tomoki Fukai
- Okinawa Institute of Science and Technology, Onna-son, Okinawa, Japan
- * E-mail: (TH); (TF)
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23
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Redolfi N, García-Casas P, Fornetto C, Sonda S, Pizzo P, Pendin D. Lighting Up Ca 2+ Dynamics in Animal Models. Cells 2021; 10:2133. [PMID: 34440902 PMCID: PMC8392631 DOI: 10.3390/cells10082133] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 08/08/2021] [Accepted: 08/16/2021] [Indexed: 12/11/2022] Open
Abstract
Calcium (Ca2+) signaling coordinates are crucial processes in brain physiology. Particularly, fundamental aspects of neuronal function such as synaptic transmission and neuronal plasticity are regulated by Ca2+, and neuronal survival itself relies on Ca2+-dependent cascades. Indeed, impaired Ca2+ homeostasis has been reported in aging as well as in the onset and progression of neurodegeneration. Understanding the physiology of brain function and the key processes leading to its derangement is a core challenge for neuroscience. In this context, Ca2+ imaging represents a powerful tool, effectively fostered by the continuous amelioration of Ca2+ sensors in parallel with the improvement of imaging instrumentation. In this review, we explore the potentiality of the most used animal models employed for Ca2+ imaging, highlighting their application in brain research to explore the pathogenesis of neurodegenerative diseases.
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Affiliation(s)
- Nelly Redolfi
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy; (N.R.); (P.G.-C.); (C.F.); (S.S.); (P.P.)
| | - Paloma García-Casas
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy; (N.R.); (P.G.-C.); (C.F.); (S.S.); (P.P.)
| | - Chiara Fornetto
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy; (N.R.); (P.G.-C.); (C.F.); (S.S.); (P.P.)
| | - Sonia Sonda
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy; (N.R.); (P.G.-C.); (C.F.); (S.S.); (P.P.)
| | - Paola Pizzo
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy; (N.R.); (P.G.-C.); (C.F.); (S.S.); (P.P.)
- Neuroscience Institute, National Research Council (CNR), 35131 Padua, Italy
| | - Diana Pendin
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy; (N.R.); (P.G.-C.); (C.F.); (S.S.); (P.P.)
- Neuroscience Institute, National Research Council (CNR), 35131 Padua, Italy
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24
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Abstract
An organism's survival can depend on its ability to recall and navigate to spatial locations associated with rewards, such as food or a home. Accumulating research has revealed that computations of reward and its prediction occur on multiple levels across a complex set of interacting brain regions, including those that support memory and navigation. However, how the brain coordinates the encoding, recall and use of reward information to guide navigation remains incompletely understood. In this Review, we propose that the brain's classical navigation centres - the hippocampus and the entorhinal cortex - are ideally suited to coordinate this larger network by representing both physical and mental space as a series of states. These states may be linked to reward via neuromodulatory inputs to the hippocampus-entorhinal cortex system. Hippocampal outputs can then broadcast sequences of states to the rest of the brain to store reward associations or to facilitate decision-making, potentially engaging additional value signals downstream. This proposal is supported by recent advances in both experimental and theoretical neuroscience. By discussing the neural systems traditionally tied to navigation and reward at their intersection, we aim to offer an integrated framework for understanding navigation to reward as a fundamental feature of many cognitive processes.
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25
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Over-representation of fundamental decision variables in the prefrontal cortex underlies decision bias. Neurosci Res 2021; 173:1-13. [PMID: 34274406 DOI: 10.1016/j.neures.2021.07.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 06/15/2021] [Accepted: 07/13/2021] [Indexed: 11/24/2022]
Abstract
The brain is organized into anatomically distinct structures consisting of a variety of projection neurons. While such evolutionarily conserved neural circuit organization underlies the innate ability of animals to swiftly adapt to environments, they can cause biased cognition and behavior. Although recent studies have begun to address the causal importance of projection-neuron types as distinct computational units, it remains unclear how projection types are functionally organized in encoding variables during cognitive tasks. This review focuses on the neural computation of decision making in the prefrontal cortex and discusses what decision variables are encoded by single neurons, neuronal populations, and projection type, alongside how specific projection types constrain decision making. We focus particularly on "over-representations" of distinct decision variables in the prefrontal cortex that reflect the biological and subjective significance of the variables for the decision makers. We suggest that task-specific over-representation in the prefrontal cortex involves the refinement of the given decision making, while generalized over-representation of fundamental decision variables is associated with suboptimal decision biases, including pathological ones such as those in patients with psychiatric disorders. Such over-representation of the fundamental decision variables in the prefrontal cortex appear to be tightly constrained by afferent and efferent connections that can be optogenetically intervened on. These ideas may provide critical insights into potential therapeutic targets for psychiatric disorders, including addiction and depression.
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26
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Takamura R, Mizuta K, Sekine Y, Islam T, Saito T, Sato M, Ohkura M, Nakai J, Ohshima T, Saido TC, Hayashi Y. Modality-Specific Impairment of Hippocampal CA1 Neurons of Alzheimer's Disease Model Mice. J Neurosci 2021; 41:5315-5329. [PMID: 33980545 PMCID: PMC8211543 DOI: 10.1523/jneurosci.0208-21.2021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 04/10/2021] [Accepted: 04/23/2021] [Indexed: 11/21/2022] Open
Abstract
Impairment of episodic memory, a class of memory for spatiotemporal context of an event, is an early symptom of Alzheimer's disease. Both spatial and temporal information are encoded and represented in the hippocampal neurons, but how these representations are impaired under amyloid β (Aβ) pathology remains elusive. We performed chronic imaging of the hippocampus in awake male amyloid precursor protein (App) knock-in mice behaving in a virtual reality environment to simultaneously monitor spatiotemporal representations and the progression of Aβ depositions. We found that temporal representation is preserved, whereas spatial representation is significantly impaired in the App knock-in mice. This is because of the overall reduction of active place cells, but not time cells, and compensatory hyperactivation of remaining place cells near Aβ aggregates. These results indicate the differential impact of Aβ aggregates on two major modalities of episodic memory, suggesting different mechanisms for forming and maintaining these two representations in the hippocampus.
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Affiliation(s)
- Risa Takamura
- Department of Pharmacology, Kyoto University Graduate School of Medicine, Kyoto 606-8501, Japan
- Department of Life Science and Medical Bioscience, Graduate School of Advanced Science and Engineering, Waseda University, Tokyo 162-8480, Japan
- Center for Brain Science, RIKEN, Saitama 351-0198, Japan
- Brain Science Institute, RIKEN, Saitama 351-0198, Japan
| | - Kotaro Mizuta
- Department of Pharmacology, Kyoto University Graduate School of Medicine, Kyoto 606-8501, Japan
- Brain Science Institute, RIKEN, Saitama 351-0198, Japan
| | - Yukiko Sekine
- Center for Brain Science, RIKEN, Saitama 351-0198, Japan
- Brain Science Institute, RIKEN, Saitama 351-0198, Japan
| | - Tanvir Islam
- Center for Brain Science, RIKEN, Saitama 351-0198, Japan
- Brain Science Institute, RIKEN, Saitama 351-0198, Japan
| | - Takashi Saito
- Center for Brain Science, RIKEN, Saitama 351-0198, Japan
- Brain Science Institute, RIKEN, Saitama 351-0198, Japan
| | - Masaaki Sato
- Center for Brain Science, RIKEN, Saitama 351-0198, Japan
- Brain Science Institute, RIKEN, Saitama 351-0198, Japan
- Brain and Body System Science Institute, Saitama University, Saitama 338-8570, Japan
| | - Masamichi Ohkura
- Brain and Body System Science Institute, Saitama University, Saitama 338-8570, Japan
| | - Junichi Nakai
- Brain and Body System Science Institute, Saitama University, Saitama 338-8570, Japan
| | - Toshio Ohshima
- Department of Life Science and Medical Bioscience, Graduate School of Advanced Science and Engineering, Waseda University, Tokyo 162-8480, Japan
| | - Takaomi C Saido
- Center for Brain Science, RIKEN, Saitama 351-0198, Japan
- Brain Science Institute, RIKEN, Saitama 351-0198, Japan
| | - Yasunori Hayashi
- Department of Pharmacology, Kyoto University Graduate School of Medicine, Kyoto 606-8501, Japan
- Brain Science Institute, RIKEN, Saitama 351-0198, Japan
- Brain and Body System Science Institute, Saitama University, Saitama 338-8570, Japan
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27
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Lee S, Kang H, Jung H, Kim E, Lee E. Gene Dosage- and Age-Dependent Differential Transcriptomic Changes in the Prefrontal Cortex of Shank2-Mutant Mice. Front Mol Neurosci 2021; 14:683196. [PMID: 34177464 PMCID: PMC8226033 DOI: 10.3389/fnmol.2021.683196] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2021] [Accepted: 05/18/2021] [Indexed: 11/20/2022] Open
Abstract
Shank2 is an abundant postsynaptic scaffolding protein that is known to regulate excitatory synapse assembly and synaptic transmission and has been implicated in various neurodevelopmental disorders, including autism spectrum disorders (ASD). Previous studies on Shank2-mutant mice provided mechanistic insights into their autistic-like phenotypes, but it remains unclear how transcriptomic patterns are changed in brain regions of the mutant mice in age- and gene dosage-dependent manners. To this end, we performed RNA-Seq analyses of the transcripts from the prefrontal cortex (PFC) of heterozygous and homozygous Shank2-mutant mice lacking exons 6 and 7 at juvenile (week 3) and adult (week 12) stages. Juvenile heterozygous Shank2-mutant mice showed upregulation of glutamate synapse-related genes, downregulation of ribosomal and mitochondrial genes, and transcriptomic changes that are opposite to those observed in ASD (anti-ASD) such as upregulation of ASD_down (downregulated in ASD), GABA neuron-related, and oligodendrocyte-related genes. Juvenile homozygous Shank2 mice showed upregulation of chromatin-related genes and transcriptomic changes that are in line with those occurring in ASD (pro-ASD) such as downregulation of ASD_down, GABA neuron-related, and oligodendrocyte-related genes. Adult heterozygous and homozygous Shank2-mutant mice both exhibited downregulation of ribosomal and mitochondrial genes and pro-ASD transcriptomic changes. Therefore, the gene dosage- and age-dependent effects of Shank2 deletions in mice include differential transcriptomic changes across distinct functional contexts, including synapses, chromatin, ribosomes, mitochondria, GABA neurons, and oligodendrocytes.
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Affiliation(s)
- Seungjoon Lee
- Department of Biological Sciences, Korea Advanced Institute for Science and Technology (KAIST), Daejeon, South Korea
| | - Hyojin Kang
- Division of National Supercomputing, KISTI, Daejeon, South Korea
| | - Hwajin Jung
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, South Korea
| | - Eunjoon Kim
- Department of Biological Sciences, Korea Advanced Institute for Science and Technology (KAIST), Daejeon, South Korea.,Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, South Korea
| | - Eunee Lee
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, South Korea.,Department of Anatomy, School of Medicine, Yonsei University, Seoul, South Korea
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Mizuta K, Nakai J, Hayashi Y, Sato M. Multiple coordinated cellular dynamics mediate CA1 map plasticity. Hippocampus 2021; 31:235-243. [PMID: 33452849 PMCID: PMC7986426 DOI: 10.1002/hipo.23300] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 12/17/2020] [Accepted: 01/02/2021] [Indexed: 11/14/2022]
Abstract
In the hippocampus, spatial and nonspatial information are jointly represented as a neural map in which locations associated with salient features are over‐represented by increased densities of relevant place cells. Although we recently demonstrated that experience‐dependent establishment of these disproportionate maps is governed by selective stabilization of salient place cells following their conversion from non‐place cells, the underlying mechanism for pre‐established map reorganization remained to be understood. To this end, we investigated the changes in CA1 functional cellular maps imaged using two‐photon calcium imaging in mice performing a reward‐rearrangement task in virtual reality. Mice were pre‐trained on a virtual linear track with a visual landmark and a reward in two distinct locations. Then, they were re‐trained on the same track with the exception that the location of reward was shifted to match the landmark location. We found that, in contrast to de novo map formation, robust map reorganization occurred through parallel coordination of new place field formation, lateral shifting of existing place fields, and selective stabilization of place fields encoding salient locations. Our findings demonstrate that intricate interplay between multiple forms of cellular dynamics enables rapid updating of information stored in hippocampal maps.
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Affiliation(s)
- Kotaro Mizuta
- Department of Pharmacology, Kyoto University Graduate School of Medicine, Kyoto, Japan.,RIKEN Brain Science Institute, Wako, Saitama, Japan
| | - Junichi Nakai
- Graduate School of Science and Engineering, Saitama University, Saitama, Japan.,Brain and Body System Science Institute, Saitama University, Saitama, Japan.,Division of Oral Physiology, Tohoku University Graduate School of Dentistry, Sendai, Miyagi, Japan
| | - Yasunori Hayashi
- Department of Pharmacology, Kyoto University Graduate School of Medicine, Kyoto, Japan.,RIKEN Brain Science Institute, Wako, Saitama, Japan.,Brain and Body System Science Institute, Saitama University, Saitama, Japan
| | - Masaaki Sato
- RIKEN Brain Science Institute, Wako, Saitama, Japan.,Graduate School of Science and Engineering, Saitama University, Saitama, Japan.,Brain and Body System Science Institute, Saitama University, Saitama, Japan.,RIKEN Center for Brain Science, Wako, Saitama, Japan.,Department of Neuropharmacology, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido, Japan
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