1
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Kuroki S, Mizuseki K. CA3 Circuit Model Compressing Sequential Information in Theta Oscillation and Replay. Neural Comput 2024; 36:501-548. [PMID: 38457750 DOI: 10.1162/neco_a_01641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 11/20/2023] [Indexed: 03/10/2024]
Abstract
The hippocampus plays a critical role in the compression and retrieval of sequential information. During wakefulness, it achieves this through theta phase precession and theta sequences. Subsequently, during periods of sleep or rest, the compressed information reactivates through sharp-wave ripple events, manifesting as memory replay. However, how these sequential neuronal activities are generated and how they store information about the external environment remain unknown. We developed a hippocampal cornu ammonis 3 (CA3) computational model based on anatomical and electrophysiological evidence from the biological CA3 circuit to address these questions. The model comprises theta rhythm inhibition, place input, and CA3-CA3 plastic recurrent connection. The model can compress the sequence of the external inputs, reproduce theta phase precession and replay, learn additional sequences, and reorganize previously learned sequences. A gradual increase in synaptic inputs, controlled by interactions between theta-paced inhibition and place inputs, explained the mechanism of sequence acquisition. This model highlights the crucial role of plasticity in the CA3 recurrent connection and theta oscillational dynamics and hypothesizes how the CA3 circuit acquires, compresses, and replays sequential information.
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Affiliation(s)
- Satoshi Kuroki
- Department of Physiology, Graduate School of Medicine, Osaka Metropolitan University, Osaka, 545-8585, Japan
| | - Kenji Mizuseki
- Department of Physiology, Graduate School of Medicine, Osaka Metropolitan University, Osaka, 545-8585, Japan
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2
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Vandael D, Jonas P. Structure, biophysics, and circuit function of a "giant" cortical presynaptic terminal. Science 2024; 383:eadg6757. [PMID: 38452088 DOI: 10.1126/science.adg6757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Accepted: 01/19/2024] [Indexed: 03/09/2024]
Abstract
The hippocampal mossy fiber synapse, formed between axons of dentate gyrus granule cells and dendrites of CA3 pyramidal neurons, is a key synapse in the trisynaptic circuitry of the hippocampus. Because of its comparatively large size, this synapse is accessible to direct presynaptic recording, allowing a rigorous investigation of the biophysical mechanisms of synaptic transmission and plasticity. Furthermore, because of its placement in the very center of the hippocampal memory circuit, this synapse seems to be critically involved in several higher network functions, such as learning, memory, pattern separation, and pattern completion. Recent work based on new technologies in both nanoanatomy and nanophysiology, including presynaptic patch-clamp recording, paired recording, super-resolution light microscopy, and freeze-fracture and "flash-and-freeze" electron microscopy, has provided new insights into the structure, biophysics, and network function of this intriguing synapse. This brings us one step closer to answering a fundamental question in neuroscience: how basic synaptic properties shape higher network computations.
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Affiliation(s)
- David Vandael
- Institute of Science and Technology Austria (ISTA), A-3400 Klosterneuburg, Austria
| | - Peter Jonas
- Institute of Science and Technology Austria (ISTA), A-3400 Klosterneuburg, Austria
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3
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Piette C, Gervasi N, Venance L. Synaptic plasticity through a naturalistic lens. Front Synaptic Neurosci 2023; 15:1250753. [PMID: 38145207 PMCID: PMC10744866 DOI: 10.3389/fnsyn.2023.1250753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 11/20/2023] [Indexed: 12/26/2023] Open
Abstract
From the myriad of studies on neuronal plasticity, investigating its underlying molecular mechanisms up to its behavioral relevance, a very complex landscape has emerged. Recent efforts have been achieved toward more naturalistic investigations as an attempt to better capture the synaptic plasticity underpinning of learning and memory, which has been fostered by the development of in vivo electrophysiological and imaging tools. In this review, we examine these naturalistic investigations, by devoting a first part to synaptic plasticity rules issued from naturalistic in vivo-like activity patterns. We next give an overview of the novel tools, which enable an increased spatio-temporal specificity for detecting and manipulating plasticity expressed at individual spines up to neuronal circuit level during behavior. Finally, we put particular emphasis on works considering brain-body communication loops and macroscale contributors to synaptic plasticity, such as body internal states and brain energy metabolism.
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Affiliation(s)
- Charlotte Piette
- Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS, INSERM, Université PSL, Paris, France
| | | | - Laurent Venance
- Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS, INSERM, Université PSL, Paris, France
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4
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Çalışkan G, Demiray YE, Stork O. Comparison of three common inbred mouse strains reveals substantial differences in hippocampal GABAergic interneuron populations and in vitro network oscillations. Eur J Neurosci 2023; 58:3383-3401. [PMID: 37550182 DOI: 10.1111/ejn.16112] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 07/03/2023] [Accepted: 07/06/2023] [Indexed: 08/09/2023]
Abstract
A major challenge in neuroscience is to pinpoint neurobiological correlates of specific cognitive and neuropsychiatric traits. At the mesoscopic level, promising candidates for establishing such connections are brain oscillations that can be robustly recorded as local field potentials with varying frequencies in the hippocampus in vivo and in vitro. Inbred mouse strains show natural variation in hippocampal synaptic plasticity (e.g. long-term potentiation), a cellular correlate of learning and memory. However, their diversity in expression of different types of hippocampal network oscillations has not been fully explored. Here, we investigated hippocampal network oscillations in three widely used inbred mouse strains: C57BL/6J (B6J), C57BL/6NCrl (B6N) and 129S2/SvPasCrl (129) with the aim to identify common oscillatory characteristics in inbred mouse strains that show aberrant emotional/cognitive behaviour (B6N and 129) and compare them to "control" B6J strain. First, we detected higher gamma oscillation power in the hippocampal CA3 of both B6N and 129 strains. Second, higher incidence of hippocampal sharp wave-ripple (SPW-R) transients was evident in these strains. Third, we observed prominent differences in the densities of distinct interneuron types and CA3 associative network activity, which are indispensable for sustainment of mesoscopic network oscillations. Together, these results add further evidence to profound physiological differences among inbred mouse strains commonly used in neuroscience research.
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Affiliation(s)
- Gürsel Çalışkan
- Research Group "Synapto-Oscillopathies", Institute of Biology, Otto-von-Guericke-University, Magdeburg, Germany
- Department of Genetics and Molecular Neurobiology, Institute of Biology, Otto-von-Guericke-University, Magdeburg, Germany
- Center for Behavioral Brain Sciences (CBBS), Magdeburg, Germany
| | - Yunus E Demiray
- Department of Genetics and Molecular Neurobiology, Institute of Biology, Otto-von-Guericke-University, Magdeburg, Germany
| | - Oliver Stork
- Department of Genetics and Molecular Neurobiology, Institute of Biology, Otto-von-Guericke-University, Magdeburg, Germany
- Center for Behavioral Brain Sciences (CBBS), Magdeburg, Germany
- Center for Intervention and Research on Adaptive and Maladaptive Brain Circuits Underlying MentalHealth (C-I-R-C), Jena-Magdeburg-Halle, Germany
- German Center for Mental Health (DZPG), Site Jena-Magdeburg-Halle, Jena-Magdeburg-Halle, Germany
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5
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Spike timing-dependent plasticity and memory. Curr Opin Neurobiol 2023; 80:102707. [PMID: 36924615 DOI: 10.1016/j.conb.2023.102707] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 01/18/2023] [Accepted: 02/15/2023] [Indexed: 03/16/2023]
Abstract
Spike timing-dependent plasticity (STDP) is a bidirectional form of synaptic plasticity discovered about 30 years ago and based on the relative timing of pre- and post-synaptic spiking activity with a millisecond precision. STDP is thought to be involved in the formation of memory but the millisecond-precision spike-timing required for STDP is difficult to reconcile with the much slower timescales of behavioral learning. This review therefore aims to expose and discuss recent findings about i) the multiple STDP learning rules at both excitatory and inhibitory synapses in vitro, ii) the contribution of STDP-like synaptic plasticity in the formation of memory in vivo and iii) the implementation of STDP rules in artificial neural networks and memristive devices.
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6
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Anisimova M, van Bommel B, Wang R, Mikhaylova M, Wiegert JS, Oertner TG, Gee CE. Spike-timing-dependent plasticity rewards synchrony rather than causality. Cereb Cortex 2022; 33:23-34. [PMID: 35203089 PMCID: PMC9758582 DOI: 10.1093/cercor/bhac050] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2021] [Revised: 12/22/2021] [Accepted: 01/24/2022] [Indexed: 11/14/2022] Open
Abstract
Spike-timing-dependent plasticity (STDP) is a candidate mechanism for information storage in the brain, but the whole-cell recordings required for the experimental induction of STDP are typically limited to 1 h. This mismatch of time scales is a long-standing weakness in synaptic theories of memory. Here we use spectrally separated optogenetic stimulation to fire precisely timed action potentials (spikes) in CA3 and CA1 pyramidal cells. Twenty minutes after optogenetic induction of STDP (oSTDP), we observed timing-dependent depression (tLTD) and timing-dependent potentiation (tLTP), depending on the sequence of spiking. As oSTDP does not require electrodes, we could also assess the strength of these paired connections three days later. At this late time point, late tLTP was observed for both causal (CA3 before CA1) and anticausal (CA1 before CA3) timing, but not for asynchronous activity patterns (Δt = 50 ms). Blocking activity after induction of oSTDP prevented stable potentiation. Our results confirm that neurons wire together if they fire together, but suggest that synaptic depression after anticausal activation (tLTD) is a transient phenomenon.
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Affiliation(s)
- Margarita Anisimova
- Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Falkenried 94, D-20251 Hamburg, Germany
| | - Bas van Bommel
- Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Falkenried 94, D-20251 Hamburg, Germany,Institute for Chemistry and Biochemistry, Feie Universität Berlin, Berlin, Germany
| | - Rui Wang
- Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Falkenried 94, D-20251 Hamburg, Germany
| | - Marina Mikhaylova
- Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Falkenried 94, D-20251 Hamburg, Germany,Institute of Biology, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Jörn Simon Wiegert
- Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Falkenried 94, D-20251 Hamburg, Germany
| | | | - Christine E Gee
- Corresponding author: Institute for Synaptic Physiology, Center for Molecular Neurobiology Hamburg, Falkenried 94, 20251 Hamburg, Germany.
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7
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Milstein AD, Li Y, Bittner KC, Grienberger C, Soltesz I, Magee JC, Romani S. Bidirectional synaptic plasticity rapidly modifies hippocampal representations. eLife 2021; 10:e73046. [PMID: 34882093 PMCID: PMC8776257 DOI: 10.7554/elife.73046] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 12/08/2021] [Indexed: 11/13/2022] Open
Abstract
Learning requires neural adaptations thought to be mediated by activity-dependent synaptic plasticity. A relatively non-standard form of synaptic plasticity driven by dendritic calcium spikes, or plateau potentials, has been reported to underlie place field formation in rodent hippocampal CA1 neurons. Here, we found that this behavioral timescale synaptic plasticity (BTSP) can also reshape existing place fields via bidirectional synaptic weight changes that depend on the temporal proximity of plateau potentials to pre-existing place fields. When evoked near an existing place field, plateau potentials induced less synaptic potentiation and more depression, suggesting BTSP might depend inversely on postsynaptic activation. However, manipulations of place cell membrane potential and computational modeling indicated that this anti-correlation actually results from a dependence on current synaptic weight such that weak inputs potentiate and strong inputs depress. A network model implementing this bidirectional synaptic learning rule suggested that BTSP enables population activity, rather than pairwise neuronal correlations, to drive neural adaptations to experience.
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Affiliation(s)
- Aaron D Milstein
- Department of Neurosurgery and Stanford Neurosciences Institute, Stanford University School of MedicineStanfordUnited States
- Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School and Center for Advanced Biotechnology and Medicine, Rutgers UniversityPiscatawayUnited States
| | - Yiding Li
- Howard Hughes Medical Institute, Baylor College of MedicineHoustonUnited States
| | - Katie C Bittner
- Howard Hughes Medical Institute, Janelia Research CampusAshburnUnited States
| | | | - Ivan Soltesz
- Department of Neurosurgery and Stanford Neurosciences Institute, Stanford University School of MedicineStanfordUnited States
| | - Jeffrey C Magee
- Howard Hughes Medical Institute, Baylor College of MedicineHoustonUnited States
| | - Sandro Romani
- Howard Hughes Medical Institute, Janelia Research CampusAshburnUnited States
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8
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Magó Á, Kis N, Lükő B, Makara JK. Distinct dendritic Ca 2+ spike forms produce opposing input-output transformations in rat CA3 pyramidal cells. eLife 2021; 10:74493. [PMID: 34817378 PMCID: PMC8612760 DOI: 10.7554/elife.74493] [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: 10/06/2021] [Accepted: 10/29/2021] [Indexed: 01/09/2023] Open
Abstract
Proper integration of different inputs targeting the dendritic tree of CA3 pyramidal cells (CA3PCs) is critical for associative learning and recall. Dendritic Ca2+ spikes have been proposed to perform associative computations in other PC types by detecting conjunctive activation of different afferent input pathways, initiating afterdepolarization (ADP), and triggering burst firing. Implementation of such operations fundamentally depends on the actual biophysical properties of dendritic Ca2+ spikes; yet little is known about these properties in dendrites of CA3PCs. Using dendritic patch-clamp recordings and two-photon Ca2+ imaging in acute slices from male rats, we report that, unlike CA1PCs, distal apical trunk dendrites of CA3PCs exhibit distinct forms of dendritic Ca2+ spikes. Besides ADP-type global Ca2+ spikes, a majority of dendrites expresses a novel, fast Ca2+ spike type that is initiated locally without bAPs, can recruit additional Na+ currents, and is compartmentalized to the activated dendritic subtree. Occurrence of the different Ca2+ spike types correlates with dendritic structure, indicating morpho-functional heterogeneity among CA3PCs. Importantly, ADPs and dendritically initiated spikes produce opposing somatic output: bursts versus strictly single-action potentials, respectively. The uncovered variability of dendritic Ca2+ spikes may underlie heterogeneous input-output transformation and bursting properties of CA3PCs, and might specifically contribute to key associative and non-associative computations performed by the CA3 network.
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Affiliation(s)
- Ádám Magó
- Laboratory of Neuronal Signaling, Institute of Experimental Medicine, Budapest, Hungary
| | - Noémi Kis
- Laboratory of Neuronal Signaling, Institute of Experimental Medicine, Budapest, Hungary.,János Szentágothai School of Neurosciences, Semmelweis University, Budapest, Hungary
| | - Balázs Lükő
- Laboratory of Neuronal Signaling, Institute of Experimental Medicine, Budapest, Hungary
| | - Judit K Makara
- Laboratory of Neuronal Signaling, Institute of Experimental Medicine, Budapest, Hungary
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9
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Humphries R, Mellor JR, O'Donnell C. Acetylcholine Boosts Dendritic NMDA Spikes in a CA3 Pyramidal Neuron Model. Neuroscience 2021; 489:69-83. [PMID: 34780920 DOI: 10.1016/j.neuroscience.2021.11.014] [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: 03/01/2021] [Revised: 10/12/2021] [Accepted: 11/05/2021] [Indexed: 11/25/2022]
Abstract
Acetylcholine has been proposed to facilitate the formation of memory ensembles within the hippocampal CA3 network, by enhancing plasticity at CA3-CA3 recurrent synapses. Regenerative NMDA receptor (NMDAR) activation in CA3 neuron dendrites (NMDA spikes) increase synaptic Ca2+ influx and can trigger this synaptic plasticity. Acetylcholine inhibits potassium channels which enhances dendritic excitability and therefore could facilitate NMDA spike generation. Here, we investigate NMDAR-mediated nonlinear synaptic integration in stratum radiatum (SR) and stratum lacunosum moleculare (SLM) dendrites in a reconstructed CA3 neuron computational model and study the effect of cholinergic inhibition of potassium conductances on this nonlinearity. We found that distal SLM dendrites, with a higher input resistance, had a lower threshold for NMDA spike generation compared to SR dendrites. Simulating acetylcholine by blocking potassium channels (M-type, A-type, Ca2+-activated, and inwardly-rectifying) increased dendritic excitability and reduced the number of synapses required to generate NMDA spikes, particularly in the SR dendrites. The magnitude of this effect was heterogeneous across different dendritic branches within the same neuron. These results predict that acetylcholine facilitates dendritic integration and NMDA spike generation in selected CA3 dendrites which could strengthen connections between specific CA3 neurons to form memory ensembles.
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Affiliation(s)
- Rachel Humphries
- Center for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol, University Walk, Bristol BS8 1TD, UK; Computational Neuroscience Unit, School of Computer Science, Electrical and Electronic Engineering, and Engineering Mathematics, University of Bristol, Bristol BS8 1UB, UK
| | - Jack R Mellor
- Center for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol, University Walk, Bristol BS8 1TD, UK
| | - Cian O'Donnell
- Computational Neuroscience Unit, School of Computer Science, Electrical and Electronic Engineering, and Engineering Mathematics, University of Bristol, Bristol BS8 1UB, UK; School of Computing, Engineering and Intelligent Systems, Ulster University, Magee Campus, Northland Road, Derry/Londonderry BT48 7JL, UK.
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10
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Brandalise F, Carta S, Leone R, Helmchen F, Holtmaat A, Gerber U. Dendritic Branch-constrained N-Methyl-d-Aspartate Receptor-mediated Spikes Drive Synaptic Plasticity in Hippocampal CA3 Pyramidal Cells. Neuroscience 2021; 489:57-68. [PMID: 34634424 DOI: 10.1016/j.neuroscience.2021.10.002] [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: 03/18/2021] [Revised: 09/27/2021] [Accepted: 10/03/2021] [Indexed: 10/20/2022]
Abstract
N-methyl-d-aspartate receptor-mediated ( spikes can be causally linked to the induction of synaptic long-term potentiation (LTP) in hippocampal and cortical pyramidal cells. However, it is unclear if they regulate plasticity at a local or global scale in the dendritic tree. Here, we used dendritic patch-clamp recordings and calcium imaging to investigate the integrative properties of single dendrites of hippocampal CA3 cells. We show that local hyperpolarization of a single dendritic segment prevents NMDA spikes, their associated calcium transients, as well as LTP in a branch-specific manner. This result provides direct, causal evidence that the single dendritic branch can operate as a functional unit in regulating CA3 pyramidal cell plasticity.
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Affiliation(s)
- Federico Brandalise
- Department of Basic Neurosciences and the Center for Neuroscience, Centre Médical Universitaire (CMU), University of Geneva, 1211 Geneva, Switzerland; Former affiliation(b).
| | - Stefano Carta
- Brain Research Institute and Neuroscience Center Zurich, University of Zurich, CH-8057 Zurich, Switzerland
| | - Roberta Leone
- Department of Basic Neurosciences and the Center for Neuroscience, Centre Médical Universitaire (CMU), University of Geneva, 1211 Geneva, Switzerland
| | - Fritjof Helmchen
- Brain Research Institute and Neuroscience Center Zurich, University of Zurich, CH-8057 Zurich, Switzerland
| | - Anthony Holtmaat
- Department of Basic Neurosciences and the Center for Neuroscience, Centre Médical Universitaire (CMU), University of Geneva, 1211 Geneva, Switzerland
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11
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Prince LY, Bacon T, Humphries R, Tsaneva-Atanasova K, Clopath C, Mellor JR. Separable actions of acetylcholine and noradrenaline on neuronal ensemble formation in hippocampal CA3 circuits. PLoS Comput Biol 2021; 17:e1009435. [PMID: 34597293 PMCID: PMC8513881 DOI: 10.1371/journal.pcbi.1009435] [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: 11/17/2020] [Revised: 10/13/2021] [Accepted: 09/08/2021] [Indexed: 11/19/2022] Open
Abstract
In the hippocampus, episodic memories are thought to be encoded by the formation of ensembles of synaptically coupled CA3 pyramidal cells driven by sparse but powerful mossy fiber inputs from dentate gyrus granule cells. The neuromodulators acetylcholine and noradrenaline are separately proposed as saliency signals that dictate memory encoding but it is not known if they represent distinct signals with separate mechanisms. Here, we show experimentally that acetylcholine, and to a lesser extent noradrenaline, suppress feed-forward inhibition and enhance Excitatory-Inhibitory ratio in the mossy fiber pathway but CA3 recurrent network properties are only altered by acetylcholine. We explore the implications of these findings on CA3 ensemble formation using a hierarchy of models. In reconstructions of CA3 pyramidal cells, mossy fiber pathway disinhibition facilitates postsynaptic dendritic depolarization known to be required for synaptic plasticity at CA3-CA3 recurrent synapses. We further show in a spiking neural network model of CA3 how acetylcholine-specific network alterations can drive rapid overlapping ensemble formation. Thus, through these distinct sets of mechanisms, acetylcholine and noradrenaline facilitate the formation of neuronal ensembles in CA3 that encode salient episodic memories in the hippocampus but acetylcholine selectively enhances the density of memory storage.
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Affiliation(s)
- Luke Y. Prince
- Centre for Synaptic Plasticity, School of Physiology Pharmacology, and Neuroscience, University of Bristol, Bristol, United Kingdom
- Mila, Montreal, Quebec, Canada
- School of Computer Science, McGill University, Montreal, Quebec, Canada
| | - Travis Bacon
- Centre for Synaptic Plasticity, School of Physiology Pharmacology, and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Rachel Humphries
- Centre for Synaptic Plasticity, School of Physiology Pharmacology, and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Krasimira Tsaneva-Atanasova
- Department of Mathematics and Living Systems Institute, University of Exeter, Exeter, United Kingdom
- EPRSC Centre for Predictive Modelling in Healthcare, University of Exeter, Exeter, United Kingdom
| | - Claudia Clopath
- Bioengineering Department, Imperial College London, London, United Kingdom
| | - Jack R. Mellor
- Centre for Synaptic Plasticity, School of Physiology Pharmacology, and Neuroscience, University of Bristol, Bristol, United Kingdom
- * E-mail:
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12
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Payeur A, Guerguiev J, Zenke F, Richards BA, Naud R. Burst-dependent synaptic plasticity can coordinate learning in hierarchical circuits. Nat Neurosci 2021; 24:1010-1019. [PMID: 33986551 DOI: 10.1038/s41593-021-00857-x] [Citation(s) in RCA: 72] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 04/15/2021] [Indexed: 01/25/2023]
Abstract
Synaptic plasticity is believed to be a key physiological mechanism for learning. It is well established that it depends on pre- and postsynaptic activity. However, models that rely solely on pre- and postsynaptic activity for synaptic changes have, so far, not been able to account for learning complex tasks that demand credit assignment in hierarchical networks. Here we show that if synaptic plasticity is regulated by high-frequency bursts of spikes, then pyramidal neurons higher in a hierarchical circuit can coordinate the plasticity of lower-level connections. Using simulations and mathematical analyses, we demonstrate that, when paired with short-term synaptic dynamics, regenerative activity in the apical dendrites and synaptic plasticity in feedback pathways, a burst-dependent learning rule can solve challenging tasks that require deep network architectures. Our results demonstrate that well-known properties of dendrites, synapses and synaptic plasticity are sufficient to enable sophisticated learning in hierarchical circuits.
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Affiliation(s)
- Alexandre Payeur
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada.,Ottawa Brain and Mind Institute, University of Ottawa, Ottawa, ON, Canada.,Centre for Neural Dynamics, University of Ottawa, Ottawa, ON, Canada.,University of Montréal and Mila, Montréal, QC, Canada
| | - Jordan Guerguiev
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON, Canada.,Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
| | - Friedemann Zenke
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Blake A Richards
- Mila, Montréal, QC, Canada. .,Department of Neurology and Neurosurgery, McGill University, Montréal, QC, Canada. .,School of Computer Science, McGill University, Montréal, QC, Canada. .,Learning in Machines and Brains Program, Canadian Institute for Advanced Research, Toronto, ON, Canada.
| | - Richard Naud
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada. .,Ottawa Brain and Mind Institute, University of Ottawa, Ottawa, ON, Canada. .,Centre for Neural Dynamics, University of Ottawa, Ottawa, ON, Canada. .,Department of Physics, University of Ottawa, Ottawa, ON, Canada.
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13
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Avchalumov Y, Mandyam CD. Plasticity in the Hippocampus, Neurogenesis and Drugs of Abuse. Brain Sci 2021; 11:404. [PMID: 33810204 PMCID: PMC8004884 DOI: 10.3390/brainsci11030404] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 03/05/2021] [Accepted: 03/11/2021] [Indexed: 02/07/2023] Open
Abstract
Synaptic plasticity in the hippocampus assists with consolidation and storage of long-lasting memories. Decades of research has provided substantial information on the cellular and molecular mechanisms underlying synaptic plasticity in the hippocampus, and this review discusses these mechanisms in brief. Addiction is a chronic relapsing disorder with loss of control over drug taking and drug seeking that is caused by long-lasting memories of drug experience. Relapse to drug use is caused by exposure to context and cues associated with the drug experience, and is a major clinical problem that contributes to the persistence of addiction. This review also briefly discusses some evidence that drugs of abuse alter plasticity in the hippocampus, and that development of novel treatment strategies that reverse or prevent drug-induced synaptic alterations in the hippocampus may reduce relapse behaviors associated with addiction.
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Affiliation(s)
| | - Chitra D. Mandyam
- VA San Diego Healthcare System, San Diego, CA 92161, USA;
- Department of Anesthesiology, University of California San Diego, San Diego, CA 92161, USA
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14
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Brandalise F, Ratto D, Leone R, Olivero F, Roda E, Locatelli CA, Grazia Bottone M, Rossi P. Deeper and Deeper on the Role of BK and Kir4.1 Channels in Glioblastoma Invasiveness: A Novel Summative Mechanism? Front Neurosci 2020; 14:595664. [PMID: 33328867 PMCID: PMC7734145 DOI: 10.3389/fnins.2020.595664] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 11/09/2020] [Indexed: 12/21/2022] Open
Abstract
In the last decades, increasing evidence has revealed that a large number of channel protein and ion pumps exhibit impaired expression in cancers. This dysregulation is responsible for high proliferative rates as well as migration and invasiveness, reflected in the recently coined term oncochannelopathies. In glioblastoma (GBM), the most invasive and aggressive primary brain tumor, GBM cells modify their ionic equilibrium in order to change their volume as a necessary step prior to migration. This mechanism involves increased expression of BK channels and downregulation of the normally widespread Kir4.1 channels, as noted in GBM biopsies from patients. Despite a large body of work implicating BK channels in migration in response to an artificial intracellular calcium rise, little is known about how this channel acts in GBM cells at resting membrane potential (RMP), as compared to other channels that are constitutively open, such as Kir4.1. In this review we propose that a residual fraction of functionally active Kir4.1 channels mediates a small, but continuous, efflux of potassium at the more depolarized RMP of GBM cells. In addition, coinciding with transient membrane deformation and the intracellular rise in calcium concentration, brief activity of BK channels can induce massive and rapid cytosolic water loss that reduces cell volume (cell shrinkage), a necessary step for migration within the brain parenchyma.
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Affiliation(s)
- Federico Brandalise
- Department of Fundamental Neurosciences (NEUFO), University of Geneva, Geneva, Switzerland
| | - Daniela Ratto
- Department of Biology and Biotechnology "L. Spallanzani," University of Pavia, Pavia, Italy
| | - Roberta Leone
- Department of Fundamental Neurosciences (NEUFO), University of Geneva, Geneva, Switzerland
| | - Federico Olivero
- Department of Biology and Biotechnology "L. Spallanzani," University of Pavia, Pavia, Italy
| | - Elisa Roda
- Department of Biology and Biotechnology "L. Spallanzani," University of Pavia, Pavia, Italy.,Pavia Poison Centre, National Toxicology Information Centre, Laboratory of Clinical & Experimental Toxicology, Toxicology Unit, Istituti Clinici Scientifici Maugeri IRCCS, Pavia, Italy
| | - Carlo Alessandro Locatelli
- Pavia Poison Centre, National Toxicology Information Centre, Laboratory of Clinical & Experimental Toxicology, Toxicology Unit, Istituti Clinici Scientifici Maugeri IRCCS, Pavia, Italy
| | - Maria Grazia Bottone
- Department of Biology and Biotechnology "L. Spallanzani," University of Pavia, Pavia, Italy
| | - Paola Rossi
- Department of Biology and Biotechnology "L. Spallanzani," University of Pavia, Pavia, Italy
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15
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Meissner-Bernard C, Tsai MC, Logiaco L, Gerstner W. Dendritic Voltage Recordings Explain Paradoxical Synaptic Plasticity: A Modeling Study. Front Synaptic Neurosci 2020; 12:585539. [PMID: 33224033 PMCID: PMC7670913 DOI: 10.3389/fnsyn.2020.585539] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 09/23/2020] [Indexed: 11/21/2022] Open
Abstract
Experiments have shown that the same stimulation pattern that causes Long-Term Potentiation in proximal synapses, will induce Long-Term Depression in distal ones. In order to understand these, and other, surprising observations we use a phenomenological model of Hebbian plasticity at the location of the synapse. Our model describes the Hebbian condition of joint activity of pre- and postsynaptic neurons in a compact form as the interaction of the glutamate trace left by a presynaptic spike with the time course of the postsynaptic voltage. Instead of simulating the voltage, we test the model using experimentally recorded dendritic voltage traces in hippocampus and neocortex. We find that the time course of the voltage in the neighborhood of a stimulated synapse is a reliable predictor of whether a stimulated synapse undergoes potentiation, depression, or no change. Our computational model can explain the existence of different -at first glance seemingly paradoxical- outcomes of synaptic potentiation and depression experiments depending on the dendritic location of the synapse and the frequency or timing of the stimulation.
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Affiliation(s)
| | | | - Laureline Logiaco
- Center for Theoretical Neuroscience, Columbia University, New York, NY, United States
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16
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Soldado-Magraner S, Brandalise F, Honnuraiah S, Pfeiffer M, Moulinier M, Gerber U, Douglas R. Conditioning by subthreshold synaptic input changes the intrinsic firing pattern of CA3 hippocampal neurons. J Neurophysiol 2019; 123:90-106. [PMID: 31721636 DOI: 10.1152/jn.00506.2019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Unlike synaptic strength, intrinsic excitability is assumed to be a stable property of neurons. For example, learning of somatic conductances is generally not incorporated into computational models, and the discharge pattern of neurons in response to test stimuli is frequently used as a basis for phenotypic classification. However, it is increasingly evident that signal processing properties of neurons are more generally plastic on the timescale of minutes. Here we demonstrate that the intrinsic firing patterns of CA3 neurons of the rat hippocampus in vitro undergo rapid long-term plasticity in response to a few minutes of only subthreshold synaptic conditioning. This plasticity on the spike timing could also be induced by intrasomatic injection of subthreshold depolarizing pulses and was blocked by kinase inhibitors, indicating that discharge dynamics are modulated locally. Cluster analysis of firing patterns before and after conditioning revealed systematic transitions toward adapting and intrinsic burst behaviors, irrespective of the patterns initially exhibited by the cells. We used a conductance-based model to decide appropriate pharmacological blockade and found that the observed transitions are likely due to recruitment of low-voltage calcium and Kv7 potassium conductances. We conclude that CA3 neurons adapt their conductance profile to the subthreshold activity of their input, so that their intrinsic firing pattern is not a static signature, but rather a reflection of their history of subthreshold activity. In this way, recurrent output from CA3 neurons may collectively shape the temporal dynamics of their embedding circuits.NEW & NOTEWORTHY Although firing patterns are widely conserved across the animal phyla, it is still a mystery why nerve cells present such diversity of discharge dynamics upon somatic step currents. Adding a new timing dimension to the intrinsic plasticity literature, here we show that CA3 neurons rapidly adapt through the space of known firing patterns in response to the subthreshold signals that they receive from their embedding circuit, potentially adjusting their network processing to the temporal statistics of their circuit.
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Affiliation(s)
| | - Federico Brandalise
- Brain Research Institute, University of Zurich, Switzerland.,Department of Fundamental Neurosciences, University of Geneva, Switzerland
| | - Suraj Honnuraiah
- Institute of Neuroinformatics, University of Zurich and ETH Zurich, Switzerland
| | - Michael Pfeiffer
- Institute of Neuroinformatics, University of Zurich and ETH Zurich, Switzerland
| | - Marie Moulinier
- Department of Fundamental Neurosciences, University of Geneva, Switzerland
| | - Urs Gerber
- Brain Research Institute, University of Zurich, Switzerland
| | - Rodney Douglas
- Institute of Neuroinformatics, University of Zurich and ETH Zurich, Switzerland
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17
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Diverse synaptic and dendritic mechanisms of complex spike burst generation in hippocampal CA3 pyramidal cells. Nat Commun 2019; 10:1859. [PMID: 31015414 PMCID: PMC6478939 DOI: 10.1038/s41467-019-09767-w] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 03/27/2019] [Indexed: 01/21/2023] Open
Abstract
Complex spike bursts (CSBs) represent a characteristic firing pattern of hippocampal pyramidal cells (PCs). In CA1PCs, CSBs are driven by regenerative dendritic plateau potentials, produced by correlated entorhinal cortical and CA3 inputs that simultaneously depolarize distal and proximal dendritic domains. However, in CA3PCs neither the generation mechanisms nor the computational role of CSBs are well elucidated. We show that CSBs are induced by dendritic Ca2+ spikes in CA3PCs. Surprisingly, the ability of CA3PCs to produce CSBs is heterogeneous, with non-uniform synaptic input-output transformation rules triggering CSBs. The heterogeneity is partly related to the topographic position of CA3PCs; we identify two ion channel types, HCN and Kv2 channels, whose proximodistal activity gradients contribute to subregion-specific modulation of CSB propensity. Our results suggest that heterogeneous dendritic integrative properties, along with previously reported synaptic connectivity gradients, define functional subpopulations of CA3PCs that may support CA3 network computations underlying associative memory processes.
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18
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Williams LE, Holtmaat A. Higher-Order Thalamocortical Inputs Gate Synaptic Long-Term Potentiation via Disinhibition. Neuron 2019; 101:91-102.e4. [DOI: 10.1016/j.neuron.2018.10.049] [Citation(s) in RCA: 122] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 08/29/2018] [Accepted: 10/25/2018] [Indexed: 11/24/2022]
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19
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Kumar A, Schiff O, Barkai E, Mel BW, Poleg-Polsky A, Schiller J. NMDA spikes mediate amplification of inputs in the rat piriform cortex. eLife 2018; 7:38446. [PMID: 30575520 PMCID: PMC6333441 DOI: 10.7554/elife.38446] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 12/20/2018] [Indexed: 11/13/2022] Open
Abstract
The piriform cortex (PCx) receives direct input from the olfactory bulb (OB) and is the brain's main station for odor recognition and memory. The transformation of the odor code from OB to PCx is profound: mitral and tufted cells in olfactory glomeruli respond to individual odorant molecules, whereas pyramidal neurons (PNs) in the PCx responds to multiple, apparently random combinations of activated glomeruli. How these 'discontinuous' receptive fields are formed from OB inputs remains unknown. Counter to the prevailing view that olfactory PNs sum their inputs passively, we show for the first time that NMDA spikes within individual dendrites can both amplify OB inputs and impose combination selectivity upon them, while their ability to compartmentalize voltage signals allows different dendrites to represent different odorant combinations. Thus, the 2-layer integrative behavior of olfactory PN dendrites provides a parsimonious account for the nonlinear remapping of the odor code from bulb to cortex.
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Affiliation(s)
- Amit Kumar
- Department of Physiology, The Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology, Haifa, Israel
| | - Oded Schiff
- Department of Physiology, The Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology, Haifa, Israel
| | - Edi Barkai
- Department of Neurobiology, University of Haifa, Haifa, Israel
| | - Bartlett W Mel
- Biomedical Engineering Department, University of Southern California, Los Angeles, United States
| | - Alon Poleg-Polsky
- Department of Physiology and Biophysics, University of Colorado School of Medicine, Aurora, United States
| | - Jackie Schiller
- Department of Physiology, The Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology, Haifa, Israel
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20
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Hainmueller T, Bartos M. Parallel emergence of stable and dynamic memory engrams in the hippocampus. Nature 2018; 558:292-296. [PMID: 29875406 DOI: 10.1038/s41586-018-0191-2] [Citation(s) in RCA: 206] [Impact Index Per Article: 34.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 04/30/2018] [Indexed: 12/31/2022]
Abstract
During our daily life, we depend on memories of past experiences to plan future behaviour. These memories are represented by the activity of specific neuronal groups or 'engrams'1,2. Neuronal engrams are assembled during learning by synaptic modification, and engram reactivation represents the memorized experience 1 . Engrams of conscious memories are initially stored in the hippocampus for several days and then transferred to cortical areas 2 . In the dentate gyrus of the hippocampus, granule cells transform rich inputs from the entorhinal cortex into a sparse output, which is forwarded to the highly interconnected pyramidal cell network in hippocampal area CA3 3 . This process is thought to support pattern separation 4 (but see refs. 5,6). CA3 pyramidal neurons project to CA1, the hippocampal output region. Consistent with the idea of transient memory storage in the hippocampus, engrams in CA1 and CA2 do not stabilize over time7-10. Nevertheless, reactivation of engrams in the dentate gyrus can induce recall of artificial memories even after weeks 2 . Reconciliation of this apparent paradox will require recordings from dentate gyrus granule cells throughout learning, which has so far not been performed for more than a single day6,11,12. Here, we use chronic two-photon calcium imaging in head-fixed mice performing a multiple-day spatial memory task in a virtual environment to record neuronal activity in all major hippocampal subfields. Whereas pyramidal neurons in CA1-CA3 show precise and highly context-specific, but continuously changing, representations of the learned spatial sceneries in our behavioural paradigm, granule cells in the dentate gyrus have a spatial code that is stable over many days, with low place- or context-specificity. Our results suggest that synaptic weights along the hippocampal trisynaptic loop are constantly reassigned to support the formation of dynamic representations in downstream hippocampal areas based on a stable code provided by the dentate gyrus.
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Affiliation(s)
- Thomas Hainmueller
- Institute for Physiology I, Systemic and Cellular Neurophysiology, University of Freiburg, Freiburg, Germany.,Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Marlene Bartos
- Institute for Physiology I, Systemic and Cellular Neurophysiology, University of Freiburg, Freiburg, Germany.
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21
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Cui Y, Prokin I, Mendes A, Berry H, Venance L. Robustness of STDP to spike timing jitter. Sci Rep 2018; 8:8139. [PMID: 29802357 PMCID: PMC5970212 DOI: 10.1038/s41598-018-26436-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 05/09/2018] [Indexed: 01/26/2023] Open
Abstract
In Hebbian plasticity, neural circuits adjust their synaptic weights depending on patterned firing. Spike-timing-dependent plasticity (STDP), a synaptic Hebbian learning rule, relies on the order and timing of the paired activities in pre- and postsynaptic neurons. Classically, in ex vivo experiments, STDP is assessed with deterministic (constant) spike timings and time intervals between successive pairings, thus exhibiting a regularity that differs from biological variability. Hence, STDP emergence from noisy inputs as occurring in in vivo-like firing remains unresolved. Here, we used noisy STDP pairings where the spike timing and/or interval between pairings were jittered. We explored with electrophysiology and mathematical modeling, the impact of jitter on three forms of STDP at corticostriatal synapses: NMDAR-LTP, endocannabinoid-LTD and endocannabinoid-LTP. We found that NMDAR-LTP was highly fragile to jitter, whereas endocannabinoid-plasticity appeared more resistant. When the frequency or number of pairings was increased, NMDAR-LTP became more robust and could be expressed despite strong jittering. Our results identify endocannabinoid-plasticity as a robust form of STDP, whereas the sensitivity to jitter of NMDAR-LTP varies with activity frequency. This provides new insights into the mechanisms at play during the different phases of learning and memory and the emergence of Hebbian plasticity in in vivo-like activity.
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Affiliation(s)
- Yihui Cui
- Dynamics and Pathophysiology of Neuronal Networks Team, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS, INSERM, PSL Research University, Paris, France
| | - Ilya Prokin
- INRIA, Villeurbanne, France.,University of Lyon, LIRIS UMR5205, Villeurbanne, France
| | - Alexandre Mendes
- Dynamics and Pathophysiology of Neuronal Networks Team, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS, INSERM, PSL Research University, Paris, France
| | - Hugues Berry
- INRIA, Villeurbanne, France. .,University of Lyon, LIRIS UMR5205, Villeurbanne, France.
| | - Laurent Venance
- Dynamics and Pathophysiology of Neuronal Networks Team, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS, INSERM, PSL Research University, Paris, France.
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22
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Lisman J. Glutamatergic synapses are structurally and biochemically complex because of multiple plasticity processes: long-term potentiation, long-term depression, short-term potentiation and scaling. Philos Trans R Soc Lond B Biol Sci 2017; 372:rstb.2016.0260. [PMID: 28093558 DOI: 10.1098/rstb.2016.0260] [Citation(s) in RCA: 100] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/29/2016] [Indexed: 01/03/2023] Open
Abstract
Synapses are complex because they perform multiple functions, including at least six mechanistically different forms of plasticity. Here, I comment on recent developments regarding these processes. (i) Short-term potentiation (STP), a Hebbian process that requires small amounts of synaptic input, appears to make strong contributions to some forms of working memory. (ii) The rules for long-term potentiation (LTP) induction in CA3 have been clarified: induction does not depend obligatorily on backpropagating sodium spikes but, rather, on dendritic branch-specific N-methyl-d-aspartate (NMDA) spikes. (iii) Late LTP, a process that requires a dopamine signal (and is therefore neoHebbian), is mediated by trans-synaptic growth of the synapse, a growth that occurs about an hour after LTP induction. (iv) LTD processes are complex and include both homosynaptic and heterosynaptic forms. (v) Synaptic scaling produced by changes in activity levels are not primarily cell-autonomous, but rather depend on network activity. (vi) The evidence for distance-dependent scaling along the primary dendrite is firm, and a plausible structural-based mechanism is suggested.Ideas about the mechanisms of synaptic function need to take into consideration newly emerging data about synaptic structure. Recent super-resolution studies indicate that glutamatergic synapses are modular (module size 70-80 nm), as predicted by theoretical work. Modules are trans-synaptic structures and have high concentrations of postsynaptic density-95 (PSD-95) and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor. These modules function as quasi-independent loci of AMPA-mediated transmission and may be independently modifiable, suggesting a new understanding of quantal transmission.This article is part of the themed issue 'Integrating Hebbian and homeostatic plasticity.'
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Affiliation(s)
- John Lisman
- Biology Department, Brandeis University, Waltham, MA, USA
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23
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Schmidt-Hieber C, Nolan MF. Synaptic integrative mechanisms for spatial cognition. Nat Neurosci 2017; 20:1483-1492. [PMID: 29073648 DOI: 10.1038/nn.4652] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 08/22/2017] [Indexed: 12/11/2022]
Abstract
Synaptic integrative mechanisms have profound effects on electrical signaling in the brain that, although largely hidden from recording methods that observe the spiking activity of neurons, may be critical for the encoding, storage and retrieval of information. Here we review roles for synaptic integrative mechanisms in the selection, generation and plasticity of place and grid fields, and in related temporal codes for the representation of space. We outline outstanding questions and challenges in the testing of hypothesized models for spatial computation and memory.
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Affiliation(s)
| | - Matthew F Nolan
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, UK
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24
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Modeling somatic and dendritic spike mediated plasticity at the single neuron and network level. Nat Commun 2017; 8:706. [PMID: 28951585 PMCID: PMC5615054 DOI: 10.1038/s41467-017-00740-z] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 07/25/2017] [Indexed: 12/11/2022] Open
Abstract
Synaptic plasticity is thought to be the principal neuronal mechanism underlying learning. Models of plastic networks typically combine point neurons with spike-timing-dependent plasticity (STDP) as the learning rule. However, a point neuron does not capture the local non-linear processing of synaptic inputs allowed for by dendrites. Furthermore, experimental evidence suggests that STDP is not the only learning rule available to neurons. By implementing biophysically realistic neuron models, we study how dendrites enable multiple synaptic plasticity mechanisms to coexist in a single cell. In these models, we compare the conditions for STDP and for synaptic strengthening by local dendritic spikes. We also explore how the connectivity between two cells is affected by these plasticity rules and by different synaptic distributions. Finally, we show that how memory retention during associative learning can be prolonged in networks of neurons by including dendrites. Synaptic plasticity is the neuronal mechanism underlying learning. Here the authors construct biophysical models of pyramidal neurons that reproduce observed plasticity gradients along the dendrite and show that dendritic spike dependent LTP which is predominant in distal sections can prolong memory retention.
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25
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Abstract
Memory is an adaptation to particular temporal properties of past events, such as the frequency of occurrence of a stimulus or the coincidence of multiple stimuli. In neurons, this adaptation can be understood in terms of a hierarchical system of molecular and cellular time windows, which collectively retain information from the past. We propose that this system makes various timescales of past experience simultaneously available for future adjustment of behavior. More generally, we propose that the ability to detect and respond to temporally structured information underlies the nervous system's capacity to encode and store a memory at molecular, cellular, synaptic, and circuit levels.
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Affiliation(s)
| | - Thomas James Carew
- Center for Neural Science, New York University, 4 Washington Place, New York, NY 10003, USA.
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26
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Rebola N, Carta M, Mulle C. Operation and plasticity of hippocampal CA3 circuits: implications for memory encoding. Nat Rev Neurosci 2017; 18:208-220. [DOI: 10.1038/nrn.2017.10] [Citation(s) in RCA: 96] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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27
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Brandalise F, Carta S, Helmchen F, Lisman J, Gerber U. Dendritic NMDA spikes are necessary for timing-dependent associative LTP in CA3 pyramidal cells. Nat Commun 2016; 7:13480. [PMID: 27848967 PMCID: PMC5116082 DOI: 10.1038/ncomms13480] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 10/07/2016] [Indexed: 01/12/2023] Open
Abstract
The computational repertoire of neurons is enhanced by regenerative electrical signals initiated in dendrites. These events, referred to as dendritic spikes, can act as cell-intrinsic amplifiers of synaptic input. Among these signals, dendritic NMDA spikes are of interest in light of their correlation with synaptic LTP induction. Because it is not possible to block NMDA spikes pharmacologically while maintaining NMDA receptors available to initiate synaptic plasticity, it remains unclear whether NMDA spikes alone can trigger LTP. Here we use dendritic recordings and calcium imaging to analyse the role of NMDA spikes in associative LTP in CA3 pyramidal cells. We show that NMDA spikes produce regenerative branch-specific calcium transients. Decreasing the probability of NMDA spikes reduces LTP, whereas increasing their probability enhances LTP. NMDA spikes and LTP occur without back-propagating action potentials. However, action potentials can facilitate LTP induction by promoting NMDA spikes. Thus, NMDA spikes are necessary and sufficient to produce the critical postsynaptic depolarization required for associative LTP in CA3 pyramidal cells.
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Affiliation(s)
- Federico Brandalise
- Brain Research Institute, University of Zurich, CH-8057 Zurich, Switzerland.,Neuroscience Center Zurich, University of Zurich, ETH Zurich, CH-8057 Zurich, Switzerland
| | - Stefano Carta
- Brain Research Institute, University of Zurich, CH-8057 Zurich, Switzerland.,Neuroscience Center Zurich, University of Zurich, ETH Zurich, CH-8057 Zurich, Switzerland
| | - Fritjof Helmchen
- Brain Research Institute, University of Zurich, CH-8057 Zurich, Switzerland.,Neuroscience Center Zurich, University of Zurich, ETH Zurich, CH-8057 Zurich, Switzerland
| | - John Lisman
- Department of Biology and Volen Center for Complex Systems, Brandeis University, Waltham, Massachusetts 02453, USA
| | - Urs Gerber
- Brain Research Institute, University of Zurich, CH-8057 Zurich, Switzerland.,Neuroscience Center Zurich, University of Zurich, ETH Zurich, CH-8057 Zurich, Switzerland
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28
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Prince LY, Bacon TJ, Tigaret CM, Mellor JR. Neuromodulation of the Feedforward Dentate Gyrus-CA3 Microcircuit. Front Synaptic Neurosci 2016; 8:32. [PMID: 27799909 PMCID: PMC5065980 DOI: 10.3389/fnsyn.2016.00032] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Accepted: 09/20/2016] [Indexed: 12/16/2022] Open
Abstract
The feedforward dentate gyrus-CA3 microcircuit in the hippocampus is thought to activate ensembles of CA3 pyramidal cells and interneurons to encode and retrieve episodic memories. The creation of these CA3 ensembles depends on neuromodulatory input and synaptic plasticity within this microcircuit. Here we review the mechanisms by which the neuromodulators aceylcholine, noradrenaline, dopamine, and serotonin reconfigure this microcircuit and thereby infer the net effect of these modulators on the processes of episodic memory encoding and retrieval.
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Affiliation(s)
- Luke Y Prince
- Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol Bristol, UK
| | - Travis J Bacon
- Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol Bristol, UK
| | - Cezar M Tigaret
- Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol Bristol, UK
| | - Jack R Mellor
- Centre for Synaptic Plasticity, School of Physiology, Pharmacology and Neuroscience, University of Bristol Bristol, UK
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29
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Functional and structural underpinnings of neuronal assembly formation in learning. Nat Neurosci 2016; 19:1553-1562. [PMID: 27749830 DOI: 10.1038/nn.4418] [Citation(s) in RCA: 141] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 09/14/2016] [Indexed: 02/07/2023]
Abstract
Learning and memory are associated with the formation and modification of neuronal assemblies: populations of neurons that encode what has been learned and mediate memory retrieval upon recall. Functional studies of neuronal assemblies have progressed dramatically thanks to recent technological advances. Here we discuss how a focus on assembly formation and consolidation has provided a powerful conceptual framework to relate mechanistic studies of synaptic and circuit plasticity to behaviorally relevant aspects of learning and memory. Neurons are likely recruited to particular learning-related assemblies as a function of their relative excitabilities and synaptic activation, followed by selective strengthening of pre-existing synapses, formation of new connections and elimination of outcompeted synapses to ensure memory formation. Mechanistically, these processes involve linking transcription to circuit modification. They include the expression of immediate early genes and specific molecular and cellular events, supported by network-wide activities that are shaped and modulated by local inhibitory microcircuits.
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30
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Kim Y, Hsu CL, Cembrowski MS, Mensh BD, Spruston N. Dendritic sodium spikes are required for long-term potentiation at distal synapses on hippocampal pyramidal neurons. eLife 2015; 4:e06414. [PMID: 26247712 PMCID: PMC4576155 DOI: 10.7554/elife.06414] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Accepted: 08/05/2015] [Indexed: 12/12/2022] Open
Abstract
Dendritic integration of synaptic inputs mediates rapid neural computation as well as longer-lasting plasticity. Several channel types can mediate dendritically initiated spikes (dSpikes), which may impact information processing and storage across multiple timescales; however, the roles of different channels in the rapid vs long-term effects of dSpikes are unknown. We show here that dSpikes mediated by Nav channels (blocked by a low concentration of TTX) are required for long-term potentiation (LTP) in the distal apical dendrites of hippocampal pyramidal neurons. Furthermore, imaging, simulations, and buffering experiments all support a model whereby fast Nav channel-mediated dSpikes (Na-dSpikes) contribute to LTP induction by promoting large, transient, localized increases in intracellular calcium concentration near the calcium-conducting pores of NMDAR and L-type Cav channels. Thus, in addition to contributing to rapid neural processing, Na-dSpikes are likely to contribute to memory formation via their role in long-lasting synaptic plasticity.
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Affiliation(s)
- Yujin Kim
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
- Department of Neurobiology, Northwestern University, Evanston, United States
| | - Ching-Lung Hsu
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
- Department of Neurobiology, Northwestern University, Evanston, United States
| | - Mark S Cembrowski
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Brett D Mensh
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Nelson Spruston
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
- Department of Neurobiology, Northwestern University, Evanston, United States
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31
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Oikonomou KD, Singh MB, Sterjanaj EV, Antic SD. Spiny neurons of amygdala, striatum, and cortex use dendritic plateau potentials to detect network UP states. Front Cell Neurosci 2014; 8:292. [PMID: 25278841 PMCID: PMC4166350 DOI: 10.3389/fncel.2014.00292] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Accepted: 09/01/2014] [Indexed: 11/25/2022] Open
Abstract
Spiny neurons of amygdala, striatum, and cerebral cortex share four interesting features: (1) they are the most abundant cell type within their respective brain area, (2) covered by thousands of thorny protrusions (dendritic spines), (3) possess high levels of dendritic NMDA conductances, and (4) experience sustained somatic depolarizations in vivo and in vitro (UP states). In all spiny neurons of the forebrain, adequate glutamatergic inputs generate dendritic plateau potentials (“dendritic UP states”) characterized by (i) fast rise, (ii) plateau phase lasting several hundred milliseconds, and (iii) abrupt decline at the end of the plateau phase. The dendritic plateau potential propagates toward the cell body decrementally to induce a long-lasting (longer than 100 ms, most often 200–800 ms) steady depolarization (∼20 mV amplitude), which resembles a neuronal UP state. Based on voltage-sensitive dye imaging, the plateau depolarization in the soma is precisely time-locked to the regenerative plateau potential taking place in the dendrite. The somatic plateau rises after the onset of the dendritic voltage transient and collapses with the breakdown of the dendritic plateau depolarization. We hypothesize that neuronal UP states in vivo reflect the occurrence of dendritic plateau potentials (dendritic UP states). We propose that the somatic voltage waveform during a neuronal UP state is determined by dendritic plateau potentials. A mammalian spiny neuron uses dendritic plateau potentials to detect and transform coherent network activity into a ubiquitous neuronal UP state. The biophysical properties of dendritic plateau potentials allow neurons to quickly attune to the ongoing network activity, as well as secure the stable amplitudes of successive UP states.
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Affiliation(s)
- Katerina D Oikonomou
- Department of Neuroscience, University of Connecticut Health Center Farmington, CT, USA
| | - Mandakini B Singh
- Department of Neuroscience, University of Connecticut Health Center Farmington, CT, USA
| | - Enas V Sterjanaj
- Department of Neuroscience, University of Connecticut Health Center Farmington, CT, USA
| | - Srdjan D Antic
- Department of Neuroscience, University of Connecticut Health Center Farmington, CT, USA
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