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Tsotsokou G, Trompoukis G, Papatheodoropoulos C. Muscarinic Modulation of Synaptic Transmission and Short-Term Plasticity in the Dorsal and Ventral Hippocampus. Mol Cell Neurosci 2024; 129:103935. [PMID: 38703973 DOI: 10.1016/j.mcn.2024.103935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 04/29/2024] [Accepted: 04/30/2024] [Indexed: 05/06/2024] Open
Abstract
Muscarinic neurotransmission is fundamentally involved in supporting several brain functions by modulating flow of information in brain neural circuits including the hippocampus which displays a remarkable functional segregation along its longitudinal axis. However, how muscarinic neuromodulation contributes to the functional segregation along the hippocampus remains unclear. In this study we show that the nonselective muscarinic receptor agonist carbachol similarly suppresses basal synaptic transmission in the dorsal and ventral CA1 hippocampal field, in a concentration-depended manner. Furthermore, using a ten-pulse stimulation train of varying frequency we found that carbachol changes the frequency filtering properties more in ventral than dorsal hippocampus by facilitating synaptic inputs at a wide range of input frequencies in the ventral compared with dorsal hippocampus. Using the M2 receptor antagonist gallamine and the M4 receptor antagonist tropicamide, we found that M2 receptors are involved in controlling basal synaptic transmission and short-term synaptic plasticity (STSP) in the ventral but not the dorsal hippocampus, while M4 receptors participate in modulating basal synaptic transmission and STSP in both segments of the hippocampus. These results were corroborated by the higher protein expression levels of M2 receptors in the ventral compared with dorsal hippocampus. We conclude that muscarinic transmission modulates excitatory synaptic transmission and short-term synaptic plasticity along the entire rat hippocampus by acting through M4 receptors and recruiting M2 receptors only in the ventral hippocampus. Furthermore, M4 receptors appear to exert a permissive role on the actions of M2 receptors on STSP in the ventral hippocampus. This dorsoventral differentiation of muscarinic modulation is expected to have important implications in information processing along the endogenous hippocampal circuitry.
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Affiliation(s)
- Giota Tsotsokou
- Laboratory of Physiology, University of Patras, Department of Medicine, Rion, Greece
| | - George Trompoukis
- Laboratory of Physiology, University of Patras, Department of Medicine, Rion, Greece
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2
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Bilash OM, Chavlis S, Johnson CD, Poirazi P, Basu J. Lateral entorhinal cortex inputs modulate hippocampal dendritic excitability by recruiting a local disinhibitory microcircuit. Cell Rep 2023; 42:111962. [PMID: 36640337 DOI: 10.1016/j.celrep.2022.111962] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 10/31/2022] [Accepted: 12/20/2022] [Indexed: 01/06/2023] Open
Abstract
The lateral entorhinal cortex (LEC) provides multisensory information to the hippocampus, directly to the distal dendrites of CA1 pyramidal neurons. LEC neurons perform important functions for episodic memory processing, coding for contextually salient elements of an environment or experience. However, we know little about the functional circuit interactions between the LEC and the hippocampus. We combine functional circuit mapping and computational modeling to examine how long-range glutamatergic LEC projections modulate compartment-specific excitation-inhibition dynamics in hippocampal area CA1. We demonstrate that glutamatergic LEC inputs can drive local dendritic spikes in CA1 pyramidal neurons, aided by the recruitment of a disinhibitory VIP interneuron microcircuit. Our circuit mapping and modeling further reveal that LEC inputs also recruit CCK interneurons that may act as strong suppressors of dendritic spikes. These results highlight a cortically driven GABAergic microcircuit mechanism that gates nonlinear dendritic computations, which may support compartment-specific coding of multisensory contextual features within the hippocampus.
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Affiliation(s)
- Olesia M Bilash
- Neuroscience Institute, Department of Neuroscience and Physiology, New York University Grossman School of Medicine, NYU Langone Health, New York, NY 10016, USA
| | - Spyridon Chavlis
- Institute of Molecular Biology and Biotechnology (IMBB), Foundation for Research and Technology-Hellas (FORTH), Heraklion, Crete 70013, Greece
| | - Cara D Johnson
- Neuroscience Institute, Department of Neuroscience and Physiology, New York University Grossman School of Medicine, NYU Langone Health, New York, NY 10016, USA
| | - Panayiota Poirazi
- Institute of Molecular Biology and Biotechnology (IMBB), Foundation for Research and Technology-Hellas (FORTH), Heraklion, Crete 70013, Greece.
| | - Jayeeta Basu
- Neuroscience Institute, Department of Neuroscience and Physiology, New York University Grossman School of Medicine, NYU Langone Health, New York, NY 10016, USA; Center for Neural Science, New York University, New York, NY 10003, USA; Department of Psychiatry, New York University Grossman School of Medicine, NYU Langone Health, New York, NY 10016, USA.
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3
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Enhancement of Neuroglial Extracellular Matrix Formation and Physiological Activity of Dopaminergic Neural Cocultures by Macromolecular Crowding. Cells 2022; 11:cells11142131. [PMID: 35883574 PMCID: PMC9317039 DOI: 10.3390/cells11142131] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 06/28/2022] [Accepted: 07/01/2022] [Indexed: 02/06/2023] Open
Abstract
The neuroglial extracellular matrix (ECM) provides critical support and physiological cues for the proper growth, differentiation, and function of neuronal cells in the brain. However, in most in vitro settings that study neural physiology, cells are grown as monolayers on stiff surfaces that maximize adhesion and proliferation, and, therefore, they lack the physiological cues that ECM in native neuronal tissues provides. Macromolecular crowding (MMC) is a biophysical phenomenon based on the principle of excluded volume that can be harnessed to induce native ECM deposition by cells in culture. Here, we show that MMC using two species of Ficoll with vitamin C supplementation significantly boosts deposition of relevant brain ECM by cultured human astrocytes. Dopaminergic neurons cocultured on this astrocyte–ECM bed prepared under MMC treatment showed longer and denser neuronal extensions, a higher number of pre ad post synaptic contacts, and increased physiological activity, as evidenced by higher frequency calcium oscillation, compared to standard coculture conditions. When the pharmacological activity of various compounds was tested on MMC-treated cocultures, their responses were enhanced, and for apomorphine, a D2-receptor agonist, it was inverted in comparison to control cell culture conditions, thus emulating responses observed in in vivo settings. These results indicate that macromolecular crowding can harness the ECM-building potential of human astrocytes in vitro forming an ultra-flat 3D microenvironment that makes neural cultures more physiological and pharmacological relevant.
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4
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Bellot-Saez A, Stevenson R, Kékesi O, Samokhina E, Ben-Abu Y, Morley JW, Buskila Y. Neuromodulation of Astrocytic K + Clearance. Int J Mol Sci 2021; 22:ijms22052520. [PMID: 33802343 PMCID: PMC7959145 DOI: 10.3390/ijms22052520] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 02/25/2021] [Accepted: 02/25/2021] [Indexed: 12/21/2022] Open
Abstract
Potassium homeostasis is fundamental for brain function. Therefore, effective removal of excessive K+ from the synaptic cleft during neuronal activity is paramount. Astrocytes play a key role in K+ clearance from the extracellular milieu using various mechanisms, including uptake via Kir channels and the Na+-K+ ATPase, and spatial buffering through the astrocytic gap-junction coupled network. Recently we showed that alterations in the concentrations of extracellular potassium ([K+]o) or impairments of the astrocytic clearance mechanism affect the resonance and oscillatory behavior of both the individual and networks of neurons. These results indicate that astrocytes have the potential to modulate neuronal network activity, however, the cellular effectors that may affect the astrocytic K+ clearance process are still unknown. In this study, we have investigated the impact of neuromodulators, which are known to mediate changes in network oscillatory behavior, on the astrocytic clearance process. Our results suggest that while some neuromodulators (5-HT; NA) might affect astrocytic spatial buffering via gap-junctions, others (DA; Histamine) primarily affect the uptake mechanism via Kir channels. These results suggest that neuromodulators can affect network oscillatory activity through parallel activation of both neurons and astrocytes, establishing a synergistic mechanism to maximize the synchronous network activity.
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Affiliation(s)
- Alba Bellot-Saez
- School of Medicine, Western Sydney University, Campbelltown, NSW 2560, Australia; (A.B.-S.); (R.S.); (O.K.); (E.S.); (J.W.M.)
| | - Rebecca Stevenson
- School of Medicine, Western Sydney University, Campbelltown, NSW 2560, Australia; (A.B.-S.); (R.S.); (O.K.); (E.S.); (J.W.M.)
| | - Orsolya Kékesi
- School of Medicine, Western Sydney University, Campbelltown, NSW 2560, Australia; (A.B.-S.); (R.S.); (O.K.); (E.S.); (J.W.M.)
| | - Evgeniia Samokhina
- School of Medicine, Western Sydney University, Campbelltown, NSW 2560, Australia; (A.B.-S.); (R.S.); (O.K.); (E.S.); (J.W.M.)
| | - Yuval Ben-Abu
- Projects and Physics Section, Sapir Academic College, D.N. Hof Ashkelon, Sderot 79165, Israel;
| | - John W. Morley
- School of Medicine, Western Sydney University, Campbelltown, NSW 2560, Australia; (A.B.-S.); (R.S.); (O.K.); (E.S.); (J.W.M.)
| | - Yossi Buskila
- School of Medicine, Western Sydney University, Campbelltown, NSW 2560, Australia; (A.B.-S.); (R.S.); (O.K.); (E.S.); (J.W.M.)
- International Centre for Neuromorphic Systems, The MARCS Institute, Western Sydney University, Penrith, NSW 2751, Australia
- Correspondence: ; Tel.: +61-246203853
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5
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Korshunov KS, Blakemore LJ, Bertram R, Trombley PQ. Spiking and Membrane Properties of Rat Olfactory Bulb Dopamine Neurons. Front Cell Neurosci 2020; 14:60. [PMID: 32265662 PMCID: PMC7100387 DOI: 10.3389/fncel.2020.00060] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 03/02/2020] [Indexed: 11/13/2022] Open
Abstract
The mammalian olfactory bulb (OB) has a vast population of dopamine (DA) neurons, whose function is to increase odor discrimination through mostly inhibitory synaptic mechanisms. However, it is not well understood whether there is more than one neuronal type of OB DA neuron, how these neurons respond to different stimuli, and the ionic mechanisms behind those responses. In this study, we used a transgenic rat line (hTH-GFP) to identify fluorescent OB DA neurons for recording via whole-cell electrophysiology. These neurons were grouped based on their localization in the glomerular layer ("Top" vs. "Bottom") with these largest and smallest neurons grouped by neuronal area ("Large" vs. "Small," in μm2). We found that some membrane properties could be distinguished based on a neuron's area, but not by its glomerular localization. All OB DA neurons produced a single action potential when receiving a sufficiently depolarizing stimulus, while some could also spike multiple times when receiving weaker stimuli, an activity that was more likely in Large than Small neurons. This single spiking activity is likely driven by the Na+ current, which showed a sensitivity to inactivation by depolarization and a relatively long time constant for the removal of inactivation. These recordings showed that Small neurons were more sensitive to inactivation of Na+ current at membrane potentials of -70 and -60 mV than Large neurons. The hyperpolarization-activated H-current (identified by voltage sags) was more pronounced in Small than Large DA neurons across hyperpolarized membrane potentials. Lastly, to mimic a more physiological stimulus, these neurons received ramp stimuli of various durations and current amplitudes. When stimulated with weaker/shallow ramps, the neurons needed less current to begin and end firing and they produced more action potentials at a slower frequency. These spiking properties were further analyzed between the four groups of neurons, and these analyses support the difference in spiking induced with current step stimuli. Thus, there may be more than one type of OB DA neuron, and these neurons' activities may support a possible role of being high-pass filters in the OB by allowing the transmission of stronger odor signals while inhibiting weaker ones.
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Affiliation(s)
- Kirill S Korshunov
- Program in Neuroscience, Florida State University, Tallahassee, FL, United States.,Department of Biological Science, Florida State University, Tallahassee, FL, United States
| | - Laura J Blakemore
- Program in Neuroscience, Florida State University, Tallahassee, FL, United States.,Department of Biological Science, Florida State University, Tallahassee, FL, United States
| | - Richard Bertram
- Program in Neuroscience, Florida State University, Tallahassee, FL, United States.,Department of Mathematics, Florida State University, Tallahassee, FL, United States
| | - Paul Q Trombley
- Program in Neuroscience, Florida State University, Tallahassee, FL, United States.,Department of Biological Science, Florida State University, Tallahassee, FL, United States
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6
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Thibeault KC, Kutlu MG, Sanders C, Calipari ES. Cell-type and projection-specific dopaminergic encoding of aversive stimuli in addiction. Brain Res 2019; 1713:1-15. [PMID: 30580012 PMCID: PMC6506354 DOI: 10.1016/j.brainres.2018.12.024] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 11/26/2018] [Accepted: 12/16/2018] [Indexed: 01/02/2023]
Abstract
Drug addiction is a major public health concern across the world for which there are limited treatment options. In order to develop new therapies to correct the behavioral deficits that result from repeated drug use, we need to understand the neural circuit dysfunction that underlies the pathophysiology of the disorder. Because the initial reinforcing effects of drugs are dependent on increases in dopamine in reward-related brain regions such as the mesolimbic dopamine pathway, a large focus of addiction research has centered on the dysregulation of this system and its control of positive reinforcement and motivation. However, in addition to the processing of positive, rewarding stimuli, there are clear deficits in the encoding and valuation of information about potential negative outcomes and how they control decision making and motivation. Further, aversive stimuli can motivate or suppress behavior depending on the context in which they are encountered. We propose a model where rewarding and aversive information guides the execution of specific motivated actions through mesocortical and mesolimbic dopamine acting on D1- and D2- receptor containing neuronal populations. Volitional drug exposure alters the processing of rewarding and aversive stimuli through remodeling of these dopaminergic circuits, causing maladaptive drug seeking, self-administration in the face of negative consequences, and drug craving. Together, this review discusses the dysfunction of the circuits controlling different types of aversive learning as well as how these guide specific discrete behaviors, and provides a conceptual framework for how they should be considered in preclinical addiction models.
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Affiliation(s)
- Kimberly C Thibeault
- Vanderbilt Center for Addiction Research, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Vanderbilt Brain Institute, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Munir Gunes Kutlu
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Christina Sanders
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Erin S Calipari
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Vanderbilt Center for Addiction Research, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Vanderbilt Brain Institute, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
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7
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Jung MW, Lee H, Jeong Y, Lee JW, Lee I. Remembering rewarding futures: A simulation-selection model of the hippocampus. Hippocampus 2018; 28:913-930. [PMID: 30155938 PMCID: PMC6587829 DOI: 10.1002/hipo.23023] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 07/06/2018] [Accepted: 08/23/2018] [Indexed: 02/06/2023]
Abstract
Despite tremendous progress, the neural circuit dynamics underlying hippocampal mnemonic processing remain poorly understood. We propose a new model for hippocampal function-the simulation-selection model-based on recent experimental findings and neuroecological considerations. Under this model, the mammalian hippocampus evolved to simulate and evaluate arbitrary navigation sequences. Specifically, we suggest that CA3 simulates unexperienced navigation sequences in addition to remembering experienced ones, and CA1 selects from among these CA3-generated sequences, reinforcing those that are likely to maximize reward during offline idling states. High-value sequences reinforced in CA1 may allow flexible navigation toward a potential rewarding location during subsequent navigation. We argue that the simulation-selection functions of the hippocampus have evolved in mammals mostly because of the unique navigational needs of land mammals. Our model may account for why the mammalian hippocampus has evolved not only to remember, but also to imagine episodes, and how this might be implemented in its neural circuits.
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Affiliation(s)
- Min Whan Jung
- Center for Synaptic Brain Dysfunctions, Institute for Basic ScienceDaejeonSouth Korea
- Department of Biological SciencesKorea Advanced Institute of Science and TechnologyDaejeonSouth Korea
| | - Hyunjung Lee
- Department of AnatomyKyungpook National University School of MedicineDaeguSouth Korea
| | - Yeongseok Jeong
- Center for Synaptic Brain Dysfunctions, Institute for Basic ScienceDaejeonSouth Korea
- Department of Biological SciencesKorea Advanced Institute of Science and TechnologyDaejeonSouth Korea
| | - Jong Won Lee
- Center for Synaptic Brain Dysfunctions, Institute for Basic ScienceDaejeonSouth Korea
| | - Inah Lee
- Department of Brain and Cognitive SciencesSeoul National UniversitySeoulSouth Korea
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8
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Kamiński J, Mamelak AN, Birch K, Mosher CP, Tagliati M, Rutishauser U. Novelty-Sensitive Dopaminergic Neurons in the Human Substantia Nigra Predict Success of Declarative Memory Formation. Curr Biol 2018; 28:1333-1343.e4. [PMID: 29657115 PMCID: PMC5973539 DOI: 10.1016/j.cub.2018.03.024] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 02/13/2018] [Accepted: 03/13/2018] [Indexed: 12/21/2022]
Abstract
The encoding of information into long-term declarative memory is facilitated by dopamine. This process depends on hippocampal novelty signals, but it remains unknown how midbrain dopaminergic neurons are modulated by declarative-memory-based information. We recorded individual substantia nigra (SN) neurons and cortical field potentials in human patients performing a recognition memory task. We found that 25% of SN neurons were modulated by stimulus novelty. Extracellular waveform shape and anatomical location indicated that these memory-selective neurons were putatively dopaminergic. The responses of memory-selective neurons appeared 527 ms after stimulus onset, changed after a single trial, and were indicative of recognition accuracy. SN neurons phase locked to frontal cortical theta-frequency oscillations, and the extent of this coordination predicted successful memory formation. These data reveal that dopaminergic neurons in the human SN are modulated by memory signals and demonstrate a progression of information flow in the hippocampal-basal ganglia-frontal cortex loop for memory encoding.
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Affiliation(s)
- Jan Kamiński
- Department of Neurosurgery, Cedars-Sinai Medical Center, 8700 Beverly Boulevard, Los Angeles, CA 90048, USA; Computation and Neural Systems, Division of Biology and Biological Engineering, California Institute of Technology, 1200 E California Boulevard, Pasadena, CA 91125, USA.
| | - Adam N Mamelak
- Department of Neurosurgery, Cedars-Sinai Medical Center, 8700 Beverly Boulevard, Los Angeles, CA 90048, USA
| | - Kurtis Birch
- Department of Neurosurgery, Cedars-Sinai Medical Center, 8700 Beverly Boulevard, Los Angeles, CA 90048, USA
| | - Clayton P Mosher
- Department of Neurosurgery, Cedars-Sinai Medical Center, 8700 Beverly Boulevard, Los Angeles, CA 90048, USA
| | - Michele Tagliati
- Department of Neurology, Cedars-Sinai Medical Center, 8700 Beverly Boulevard, Los Angeles, CA 90048, USA
| | - Ueli Rutishauser
- Department of Neurosurgery, Cedars-Sinai Medical Center, 8700 Beverly Boulevard, Los Angeles, CA 90048, USA; Department of Neurology, Cedars-Sinai Medical Center, 8700 Beverly Boulevard, Los Angeles, CA 90048, USA; Center for Neural Science and Medicine, Department of Biomedical Sciences, Cedars-Sinai Medical Center, 8700 Beverly Boulevard, Los Angeles, CA 90048, USA; Computation and Neural Systems, Division of Biology and Biological Engineering, California Institute of Technology, 1200 E California Boulevard, Pasadena, CA 91125, USA.
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9
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Edelmann E, Lessmann V. Dopaminergic innervation and modulation of hippocampal networks. Cell Tissue Res 2018; 373:711-727. [PMID: 29470647 DOI: 10.1007/s00441-018-2800-7] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 01/17/2018] [Indexed: 02/06/2023]
Abstract
The catecholamine dopamine plays an important role in hippocampus-dependent plasticity and related learning and memory processes. Dopamine secretion in the hippocampus is activated by, e.g., salient or novel stimuli, thereby helping to establish and to stabilize hippocampus-dependent memories. Disturbed dopaminergic function in the hippocampus leads to severe pathophysiological conditions. While the role and importance of dopaminergic modulation of hippocampal networks have been unequivocally proven, there is still a lack of detailed molecular and cellular mechanistic understanding of how dopamine orchestrates these hippocampal processes. In this chapter of the special issue "Hippocampal structure and function," we will discuss the current understanding of dopaminergic modulation of basal synaptic transmission and long-lasting, activity-dependent potentiation or depression.
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Affiliation(s)
- Elke Edelmann
- Institut für Physiologie, Otto-von-Guericke-Universität, Medizinische Fakultät, Leipziger Str. 44, 39120, Magdeburg, Germany. .,Center for Behavioral Brain Sciences, Otto-von-Guericke University, Universitätsplatz 2, 39106, Magdeburg, Germany.
| | - Volkmar Lessmann
- Institut für Physiologie, Otto-von-Guericke-Universität, Medizinische Fakultät, Leipziger Str. 44, 39120, Magdeburg, Germany. .,Center for Behavioral Brain Sciences, Otto-von-Guericke University, Universitätsplatz 2, 39106, Magdeburg, Germany.
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10
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Xiong G, Metheny H, Johnson BN, Cohen AS. A Comparison of Different Slicing Planes in Preservation of Major Hippocampal Pathway Fibers in the Mouse. Front Neuroanat 2017; 11:107. [PMID: 29201002 PMCID: PMC5696601 DOI: 10.3389/fnana.2017.00107] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 11/06/2017] [Indexed: 12/03/2022] Open
Abstract
The hippocampus plays a critical role in learning and memory and higher cognitive functions, and its dysfunction has been implicated in various neuropathological disorders. Electrophysiological recording undertaken in live brain slices is one of the most powerful tools for investigating hippocampal cellular and network activities. The plane for cutting the slices determines which afferent and/or efferent connections are best preserved, and there are three commonly used slices: hippocampal-entorhinal cortex (HEC), coronal and transverse. All three slices have been widely used for studying the major afferent hippocampal pathways including the perforant path (PP), the mossy fibers (MFs) and the Schaffer collaterals (SCs). Surprisingly, there has never been a systematic investigation of the anatomical and functional consequences of slicing at a particular angle. In the present study, we focused on how well fiber pathways are preserved from the entorhinal cortex (EC) to the hippocampus, and within the hippocampus, in slices generated by sectioning at different angles. The postmortem neural tract tracer 1,1′-dioctadecyl-3,3,3′3′-tetramethylindocarbocyanine perchlorate (DiI) was used to label afferent fibers to hippocampal principal neurons in fixed slices or whole brains. Laser scanning confocal microscopy was adopted for imaging DiI-labeled axons and terminals. We demonstrated that PP fibers were well preserved in HEC slices, MFs in both HEC and transverse slices and SCs in all three types of slices. Correspondingly, field excitatory postsynaptic potentials (fEPSPs) could be consistently evoked in HEC slices when stimulating PP fibers and recorded in stratum lacunosum-moleculare (sl-m) of area CA1, and when stimulating the dentate granule cell layer (gcl) and recording in stratum lucidum (sl) of area CA3. The MF evoked fEPSPs could not be recorded in CA3 from coronal slices. In contrast to our DiI-tracing data demonstrating severely truncated PP fibers in coronal slices, fEPSPs could still be recorded in CA1 sl-m in this plane, suggesting that an additional afferent fiber pathway other than PP might be involved. The present study increases our understanding of which hippocampal pathways are best preserved in the three most common brain slice preparations, and will help investigators determine the appropriate slices to use for physiological studies depending on the subregion of interest.
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Affiliation(s)
- Guoxiang Xiong
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Philadelphia, PA, United States
| | - Hannah Metheny
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Philadelphia, PA, United States
| | - Brian N Johnson
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Philadelphia, PA, United States
| | - Akiva S Cohen
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Philadelphia, PA, United States.,Department of Anesthesiology and Critical Care Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
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11
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McKenzie S. Inhibition shapes the organization of hippocampal representations. Hippocampus 2017; 28:659-671. [PMID: 28921762 DOI: 10.1002/hipo.22803] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 09/11/2017] [Accepted: 09/13/2017] [Indexed: 01/12/2023]
Abstract
Hippocampal neurons become tuned to stimuli that predict behaviorally salient outcomes. This plasticity suggests that memory formation depends upon shifts in how different anatomical inputs can drive hippocampal activity. Here, I present evidence that inhibitory neurons can provide such a mechanism for learning-related changes in the tuning of pyramidal cells. Inhibitory currents arriving on the dendrites of pyramidal cells determine whether an excitatory input can drive action potential output. Specificity and plasticity of this dendritic modulation allows for precise, modifiable changes in how afferent inputs are integrated, a process that defines a neuron's receptive field. In addition, feedback inhibition plays a fundamental role in biasing which excitatory neurons may be co-active. By defining the rules of synchrony and the rules of input integration, interneurons likely play an important role in the organization of memory representation within the hippocampus.
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Affiliation(s)
- Sam McKenzie
- NYU Langone Medical Center, 450 E29th Street, 9th Floor, New York, New York 10016
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12
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Helbing C, Tischmeyer W, Angenstein F. Late effect of dopamine D 1/5 receptor activation on stimulus-induced BOLD responses in the hippocampus and its target regions depends on the history of previous stimulations. Neuroimage 2017; 152:119-129. [DOI: 10.1016/j.neuroimage.2017.02.077] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 02/23/2017] [Accepted: 02/25/2017] [Indexed: 10/20/2022] Open
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13
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Korshunov KS, Blakemore LJ, Trombley PQ. Dopamine: A Modulator of Circadian Rhythms in the Central Nervous System. Front Cell Neurosci 2017; 11:91. [PMID: 28420965 PMCID: PMC5376559 DOI: 10.3389/fncel.2017.00091] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 03/15/2017] [Indexed: 01/11/2023] Open
Abstract
Circadian rhythms are daily rhythms that regulate many biological processes – from gene transcription to behavior – and a disruption of these rhythms can lead to a myriad of health risks. Circadian rhythms are entrained by light, and their 24-h oscillation is maintained by a core molecular feedback loop composed of canonical circadian (“clock”) genes and proteins. Different modulators help to maintain the proper rhythmicity of these genes and proteins, and one emerging modulator is dopamine. Dopamine has been shown to have circadian-like activities in the retina, olfactory bulb, striatum, midbrain, and hypothalamus, where it regulates, and is regulated by, clock genes in some of these areas. Thus, it is likely that dopamine is essential to mechanisms that maintain proper rhythmicity of these five brain areas. This review discusses studies that showcase different dopaminergic mechanisms that may be involved with the regulation of these brain areas’ circadian rhythms. Mechanisms include how dopamine and dopamine receptor activity directly and indirectly influence clock genes and proteins, how dopamine’s interactions with gap junctions influence daily neuronal excitability, and how dopamine’s release and effects are gated by low- and high-pass filters. Because the dopamine neurons described in this review also release the inhibitory neurotransmitter GABA which influences clock protein expression in the retina, we discuss articles that explore how GABA may contribute to the actions of dopamine neurons on circadian rhythms. Finally, to understand how the loss of function of dopamine neurons could influence circadian rhythms, we review studies linking the neurodegenerative disease Parkinson’s Disease to disruptions of circadian rhythms in these five brain areas. The purpose of this review is to summarize growing evidence that dopamine is involved in regulating circadian rhythms, either directly or indirectly, in the brain areas discussed here. An appreciation of the growing evidence of dopamine’s influence on circadian rhythms may lead to new treatments including pharmacological agents directed at alleviating the various symptoms of circadian rhythm disruption.
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Affiliation(s)
- Kirill S Korshunov
- Program in Neuroscience, Florida State University,Tallahassee, FL, USA.,Department of Biological Science, Florida State University,Tallahassee, FL, USA
| | - Laura J Blakemore
- Program in Neuroscience, Florida State University,Tallahassee, FL, USA.,Department of Biological Science, Florida State University,Tallahassee, FL, USA
| | - Paul Q Trombley
- Program in Neuroscience, Florida State University,Tallahassee, FL, USA.,Department of Biological Science, Florida State University,Tallahassee, FL, USA
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14
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Iñiguez SD, Aubry A, Riggs LM, Alipio JB, Zanca RM, Flores-Ramirez FJ, Hernandez MA, Nieto SJ, Musheyev D, Serrano PA. Social defeat stress induces depression-like behavior and alters spine morphology in the hippocampus of adolescent male C57BL/6 mice. Neurobiol Stress 2016; 5:54-64. [PMID: 27981196 PMCID: PMC5154707 DOI: 10.1016/j.ynstr.2016.07.001] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 07/16/2016] [Accepted: 07/29/2016] [Indexed: 12/18/2022] Open
Abstract
Social stress, including bullying during adolescence, is a risk factor for common psychopathologies such as depression. To investigate the neural mechanisms associated with juvenile social stress-induced mood-related endophenotypes, we examined the behavioral, morphological, and biochemical effects of the social defeat stress model of depression on hippocampal dendritic spines within the CA1 stratum radiatum. Adolescent (postnatal day 35) male C57BL/6 mice were subjected to defeat episodes for 10 consecutive days. Twenty-four h later, separate groups of mice were tested on the social interaction and tail suspension tests. Hippocampi were then dissected and Western blots were conducted to quantify protein levels for various markers important for synaptic plasticity including protein kinase M zeta (PKMζ), protein kinase C zeta (PKCζ), the dopamine-1 (D1) receptor, tyrosine hydroxylase (TH), and the dopamine transporter (DAT). Furthermore, we examined the presence of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-receptor subunit GluA2 as well as colocalization with the post-synaptic density 95 (PSD95) protein, within different spine subtypes (filopodia, stubby, long-thin, mushroom) using an immunohistochemistry and Golgi-Cox staining technique. The results revealed that social defeat induced a depression-like behavioral profile, as inferred from decreased social interaction levels, increased immobility on the tail suspension test, and decreases in body weight. Whole hippocampal immunoblots revealed decreases in GluA2, with a concomitant increase in DAT and TH levels in the stressed group. Spine morphology analyses further showed that defeated mice displayed a significant decrease in stubby spines, and an increase in long-thin spines within the CA1 stratum radiatum. Further evaluation of GluA2/PSD95 containing-spines demonstrated a decrease of these markers within long-thin and mushroom spine types. Together, these results indicate that juvenile social stress induces GluA2- and dopamine-associated dysregulation in the hippocampus - a neurobiological mechanism potentially underlying the development of mood-related syndromes as a consequence of adolescent bullying.
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Affiliation(s)
- Sergio D. Iñiguez
- Department of Psychology, The University of Texas at El Paso, 500 W. University Ave., El Paso, TX, 79902, USA
- Department of Psychology, California State University, San Bernardino, CA, 92407, USA
| | - Antonio Aubry
- Department of Psychology, Hunter College, New York, NY, 10065, USA
- The Graduate Center of CUNY, New York, NY, USA
| | - Lace M. Riggs
- Department of Psychology, California State University, San Bernardino, CA, 92407, USA
| | - Jason B. Alipio
- Department of Psychology, California State University, San Bernardino, CA, 92407, USA
| | | | - Francisco J. Flores-Ramirez
- Department of Psychology, The University of Texas at El Paso, 500 W. University Ave., El Paso, TX, 79902, USA
| | - Mirella A. Hernandez
- Department of Psychology, The University of Texas at El Paso, 500 W. University Ave., El Paso, TX, 79902, USA
- Department of Psychology, California State University, San Bernardino, CA, 92407, USA
| | - Steven J. Nieto
- Department of Psychology, California State University, San Bernardino, CA, 92407, USA
| | - David Musheyev
- Department of Psychology, Hunter College, New York, NY, 10065, USA
| | - Peter A. Serrano
- Department of Psychology, Hunter College, New York, NY, 10065, USA
- The Graduate Center of CUNY, New York, NY, USA
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15
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Puighermanal E, Cutando L, Boubaker-Vitre J, Honoré E, Longueville S, Hervé D, Valjent E. Anatomical and molecular characterization of dopamine D1 receptor-expressing neurons of the mouse CA1 dorsal hippocampus. Brain Struct Funct 2016; 222:1897-1911. [PMID: 27678395 PMCID: PMC5406422 DOI: 10.1007/s00429-016-1314-x] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 09/15/2016] [Indexed: 12/21/2022]
Abstract
In the hippocampus, a functional role of dopamine D1 receptors (D1R) in synaptic plasticity and memory processes has been suggested by electrophysiological and pharmacological studies. However, comprehension of their function remains elusive due to the lack of knowledge on the precise localization of D1R expression among the diversity of interneuron populations. Using BAC transgenic mice expressing enhanced green fluorescent protein under the control of D1R promoter, we examined the molecular identity of D1R-containing neurons within the CA1 subfield of the dorsal hippocampus. In agreement with previous findings, our analysis revealed that these neurons are essentially GABAergic interneurons, which express several neurochemical markers, including calcium-binding proteins, neuropeptides, and receptors among others. Finally, by using different tools comprising cell type-specific isolation of mRNAs bound to tagged-ribosomes, we provide solid data indicating that D1R is present in a large proportion of interneurons expressing dopamine D2 receptors. Altogether, our study indicates that D1Rs are expressed by different classes of interneurons in all layers examined and not by pyramidal cells, suggesting that CA1 D1R mostly acts via modulation of GABAergic interneurons.
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Affiliation(s)
- Emma Puighermanal
- CNRS UMR 5203, Institut de Génomique Fonctionnelle, 141 rue de la Cardonille, 34094, Montpellier Cedex 05, France.,INSERM, U1191, Montpellier, 34094, France.,Université de Montpellier, UMR 5203, Montpellier, 34094, France
| | - Laura Cutando
- CNRS UMR 5203, Institut de Génomique Fonctionnelle, 141 rue de la Cardonille, 34094, Montpellier Cedex 05, France.,INSERM, U1191, Montpellier, 34094, France.,Université de Montpellier, UMR 5203, Montpellier, 34094, France
| | - Jihane Boubaker-Vitre
- CNRS UMR 5203, Institut de Génomique Fonctionnelle, 141 rue de la Cardonille, 34094, Montpellier Cedex 05, France.,INSERM, U1191, Montpellier, 34094, France.,Université de Montpellier, UMR 5203, Montpellier, 34094, France
| | - Eve Honoré
- CNRS UMR 5203, Institut de Génomique Fonctionnelle, 141 rue de la Cardonille, 34094, Montpellier Cedex 05, France.,INSERM, U1191, Montpellier, 34094, France.,Université de Montpellier, UMR 5203, Montpellier, 34094, France
| | - Sophie Longueville
- Inserm, UMR-S 839, 75005, Paris, France.,Université Pierre et Marie Curie-Paris 6, 75005, Paris, France.,Institut du Fer à Moulin, 75005, Paris, France
| | - Denis Hervé
- Inserm, UMR-S 839, 75005, Paris, France.,Université Pierre et Marie Curie-Paris 6, 75005, Paris, France.,Institut du Fer à Moulin, 75005, Paris, France
| | - Emmanuel Valjent
- CNRS UMR 5203, Institut de Génomique Fonctionnelle, 141 rue de la Cardonille, 34094, Montpellier Cedex 05, France. .,INSERM, U1191, Montpellier, 34094, France. .,Université de Montpellier, UMR 5203, Montpellier, 34094, France.
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16
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Dopaminergic inputs in the dentate gyrus direct the choice of memory encoding. Proc Natl Acad Sci U S A 2016; 113:E5501-10. [PMID: 27573822 DOI: 10.1073/pnas.1606951113] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Rewarding experiences are often well remembered, and such memory formation is known to be dependent on dopamine modulation of the neural substrates engaged in learning and memory; however, it is unknown how and where in the brain dopamine signals bias episodic memory toward preceding rather than subsequent events. Here we found that photostimulation of channelrhodopsin-2-expressing dopaminergic fibers in the dentate gyrus induced a long-term depression of cortical inputs, diminished theta oscillations, and impaired subsequent contextual learning. Computational modeling based on this dopamine modulation indicated an asymmetric association of events occurring before and after reward in memory tasks. In subsequent behavioral experiments, preexposure to a natural reward suppressed hippocampus-dependent memory formation, with an effective time window consistent with the duration of dopamine-induced changes of dentate activity. Overall, our results suggest a mechanism by which dopamine enables the hippocampus to encode memory with reduced interference from subsequent experience.
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17
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Goutier W, Lowry JP, McCreary AC, O'Connor JJ. Frequency-Dependent Modulation of Dopamine Release by Nicotine and Dopamine D1 Receptor Ligands: An In Vitro Fast Cyclic Voltammetry Study in Rat Striatum. Neurochem Res 2016; 41:945-50. [PMID: 26975318 DOI: 10.1007/s11064-015-1786-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Revised: 11/19/2015] [Accepted: 11/23/2015] [Indexed: 01/23/2023]
Abstract
Nicotine is a highly addictive drug and exerts this effect partially through the modulation of dopamine release and increasing extracellular dopamine in regions such as the brain reward systems. Nicotine acts in these regions on nicotinic acetylcholine receptors. The effect of nicotine on the frequency dependent modulation of dopamine release is well established and the purpose of this study was to investigate whether dopamine D1 receptor (D1R) ligands have an influence on this. Using fast cyclic voltammetry and rat corticostriatal slices, we show that D1R ligands are able to modulate the effect of nicotine on dopamine release. Nicotine (500 nM) induced a decrease in dopamine efflux at low frequency (single pulse or five pulses at 10 Hz) and an increase at high frequency (100 Hz) electrical field stimulation. The D1R agonist SKF-38393, whilst having no effect on dopamine release on its own or on the effect of nicotine upon multiple pulse evoked dopamine release, did significantly prevent and reverse the effect of nicotine on single pulse dopamine release. Interestingly similar results were obtained with the D1R antagonist SCH-23390. In this study we have demonstrated that the modulation of dopamine release by nicotine can be altered by D1R ligands, but only when evoked by single pulse stimulation, and are likely working via cholinergic interneuron driven dopamine release.
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Affiliation(s)
- W Goutier
- Abbott Healthcare Products B.V. (formerly Solvay Pharmaceuticals B.V.), C.J. van Houtenlaan 36, 1381 CP, Weesp, The Netherlands.,Maynooth University Department of Chemistry, Maynooth University, Maynooth, Co. Kildare, Ireland
| | - J P Lowry
- Maynooth University Department of Chemistry, Maynooth University, Maynooth, Co. Kildare, Ireland
| | - A C McCreary
- Abbott Healthcare Products B.V. (formerly Solvay Pharmaceuticals B.V.), C.J. van Houtenlaan 36, 1381 CP, Weesp, The Netherlands
| | - J J O'Connor
- Maynooth University Department of Chemistry, Maynooth University, Maynooth, Co. Kildare, Ireland. .,UCD School of Biomolecular and Biomedical Science, UCD Conway Institute of Biomolecular and Biomedical Research, Belfield, Dublin 4, Ireland.
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18
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Li SB, Du D, Hasan MT, Köhr G. D4 Receptor Activation Differentially Modulates Hippocampal Basal and Apical Dendritic Synapses in Freely Moving Mice. Cereb Cortex 2016; 26:647-55. [PMID: 25270308 DOI: 10.1093/cercor/bhu229] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Activation of D4 receptors (D4Rs) has been shown to improve cognitive performance, potentially affecting synaptic strength. We investigated the D4R agonist PD 168077 (PD) in hippocampal CA1 of freely moving mice. We electrically stimulated in stratum oriens (OR) or radiatum (RAD) and evoked local field potentials (LFPs). Intraperitoneally injected PD dose-dependently and reversibly attenuated LFPs for longer time in basal (OR) than apical (RAD) dendrites. High-frequency stimulation induced LTP that was stronger and more stable in OR than RAD. LTP lasted at least 4 h during which the paired-pulse ratio remained reduced. A PD concentration not affecting synaptic transmission was sufficient to reduce LTP in OR but not in RAD. A PD concentration reducing synaptic transmission reduced the early phase LTP in OR additionally and the late phase LTP in RAD exclusively. Furthermore, cell type-specific expression of mCherry in DATCre mice generated fluorescence in dorsal CA1 that was highest in lacunosum moleculare and similar in OR/RAD, indicating that midbrain dopaminergic fibers distribute evenly in OR/RAD. Together, the D4R-mediated modulation of hippocampal synaptic transmission and plasticity is stronger in OR than RAD. This could affect information processing in CA1 neurons, since signals arriving via basal and apical afferents are distinct.
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Affiliation(s)
- Shi-Bin Li
- Department of Molecular Neurobiology, Max-Planck-Institute for Medical Research, 60120 Heidelberg, Germany Current Address: Physiology of Neural Networks, Psychiatry/Psychopharmacology, Central Institute of Mental Health, J5, Heidelberg University, Mannheim 68159, Germany
| | - Dan Du
- Department of Molecular Neurobiology, Max-Planck-Institute for Medical Research, 60120 Heidelberg, Germany Current Address: Physiology of Neural Networks, Psychiatry/Psychopharmacology, Central Institute of Mental Health, J5, Heidelberg University, Mannheim 68159, Germany
| | - Mazahir T Hasan
- Department of Molecular Neurobiology, Max-Planck-Institute for Medical Research, 60120 Heidelberg, Germany Current Address: NeuroCure Cluster of Excellence, Charité-Universitätsmedizin, Berlin 12101, Germany
| | - Georg Köhr
- Department of Molecular Neurobiology, Max-Planck-Institute for Medical Research, 60120 Heidelberg, Germany Current Address: Physiology of Neural Networks, Psychiatry/Psychopharmacology, Central Institute of Mental Health, J5, Heidelberg University, Mannheim 68159, Germany
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19
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Lee JC, Wang LP, Tsien JZ. Dopamine Rebound-Excitation Theory: Putting Brakes on PTSD. Front Psychiatry 2016; 7:163. [PMID: 27729874 PMCID: PMC5037223 DOI: 10.3389/fpsyt.2016.00163] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 09/14/2016] [Indexed: 01/19/2023] Open
Abstract
It is not uncommon for humans or animals to experience traumatic events in their lifetimes. However, the majority of individuals are resilient to long-term detrimental changes turning into anxiety and depression, such as post-traumatic stress disorder (PTSD). What underlying neural mechanism accounts for individual variability in stress resilience? Hyperactivity in fear circuits, such as the amygdalar system, is well-known to be the major pathophysiological basis for PTSD, much like a "stuck accelerator." Interestingly, increasing evidence demonstrates that dopamine (DA) - traditionally known for its role in motivation, reward prediction, and addiction - is also crucial in regulating fear learning and anxiety. Yet, how dopaminergic (DAergic) neurons control stress resilience is unclear, especially given that DAergic neurons have multiple subtypes with distinct temporal dynamics. Here, we propose the Rebound-Excitation Theory, which posits that DAergic neurons' rebound-excitation at the termination of fearful experiences serves as an important "brake" by providing intrinsic safety-signals to fear-processing neural circuits in a spatially and temporally controlled manner. We discuss how DAergic neuron rebound-excitation may be regulated by genetics and experiences, and how such physiological properties may be used as a brain-activity biomarker to predict and confer individual resilience to stress and anxiety.
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Affiliation(s)
- Jason C Lee
- Department of Neurology, Brain and Behavior Discovery Institute, Medical College of Georgia, Augusta University , Augusta, GA , USA
| | - Lei Philip Wang
- Department of Neurology, Brain and Behavior Discovery Institute, Medical College of Georgia, Augusta University, Augusta, GA, USA; Department of Psychiatry, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Joe Z Tsien
- Department of Neurology, Brain and Behavior Discovery Institute, Medical College of Georgia, Augusta University , Augusta, GA , USA
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20
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Basu J, Siegelbaum SA. The Corticohippocampal Circuit, Synaptic Plasticity, and Memory. Cold Spring Harb Perspect Biol 2015; 7:7/11/a021733. [PMID: 26525152 DOI: 10.1101/cshperspect.a021733] [Citation(s) in RCA: 121] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Synaptic plasticity serves as a cellular substrate for information storage in the central nervous system. The entorhinal cortex (EC) and hippocampus are interconnected brain areas supporting basic cognitive functions important for the formation and retrieval of declarative memories. Here, we discuss how information flow in the EC-hippocampal loop is organized through circuit design. We highlight recently identified corticohippocampal and intrahippocampal connections and how these long-range and local microcircuits contribute to learning. This review also describes various forms of activity-dependent mechanisms that change the strength of corticohippocampal synaptic transmission. A key point to emerge from these studies is that patterned activity and interaction of coincident inputs gives rise to associational plasticity and long-term regulation of information flow. Finally, we offer insights about how learning-related synaptic plasticity within the corticohippocampal circuit during sensory experiences may enable adaptive behaviors for encoding spatial, episodic, social, and contextual memories.
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Affiliation(s)
- Jayeeta Basu
- Department of Neuroscience and Physiology, NYU Neuroscience Institute, New York University School of Medicine, New York, New York 10016
| | - Steven A Siegelbaum
- Kavli Institute for Brain Science, Columbia University, New York, New York 10032 Department of Neuroscience, Columbia University, New York, New York 10032 Department of Pharmacology, Columbia University, New York, New York 10032
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21
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Song W, Semework M. Tactile representation in somatosensory thalamus (VPL) and cortex (S1) of awake primate and the plasticity induced by VPL neuroprosthetic stimulation. Brain Res 2015; 1625:301-13. [PMID: 26348987 DOI: 10.1016/j.brainres.2015.08.046] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Revised: 08/20/2015] [Accepted: 08/31/2015] [Indexed: 11/19/2022]
Abstract
To further understand how tactile information is carried in somatosensory cortex (S1) and the thalamus (VPL), and how neuronal plasticity after neuroprosthetic stimulation affects sensory encoding, we chronically implanted microelectrode arrays across hand areas in both S1 and VPL, where neuronal activities were simultaneously recorded during tactile stimulation on the finger pad of awake monkeys. Tactile information encoded in the firing rate of individual units (rate coding) or in the synchrony of unit pairs (synchrony coding) was quantitatively assessed within the information theoretic-framework. We found that tactile information encoded in VPL was higher than that encoded in S1 for both rate coding and synchrony coding; rate coding carried greater information than synchrony coding for the same recording area. With the aim for neuroprosthetic stimulation, plasticity of the circuit was tested after 30 min of VPL electrical stimulation, where stimuli were delivered either randomly or contingent on the spiking of an S1 unit. We showed that neural encoding in VPL was more stable than in S1, which depends not only on the thalamic input but also on recurrent feedback. The percent change of mutual-information after stimulation was increased with closed-loop stimulation, but decreased with random stimulation. The underlying mechanisms during closed-loop stimulation might be spike-timing-dependent plasticity, while frequency-dependent synaptic plasticity might play a role in random stimulation. Our results suggest that VPL could be a promising target region for somatosensory stimulation with closed-loop brain-machine-interface applications.
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Affiliation(s)
- Weiguo Song
- Department of Physiology and Pharmacology, SUNY Downstate Medical Center, NY 11203, USA.
| | - Mulugeta Semework
- Joint Graduate Program in Biomedical Engineering SUNY Downstate and NYU-POLY, NY 11203, USA
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22
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Leptin Induces a Novel Form of NMDA Receptor-Dependent LTP at Hippocampal Temporoammonic-CA1 Synapses. eNeuro 2015; 2:eN-NWR-0007-15. [PMID: 26464986 PMCID: PMC4586932 DOI: 10.1523/eneuro.0007-15.2015] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Revised: 05/12/2015] [Accepted: 05/15/2015] [Indexed: 01/08/2023] Open
Abstract
Hippocampal CA1 pyramidal neurons receive two anatomically distinct glutamatergic inputs that have distinct roles in learning and memory. The hormone leptin markedly influences excitatory synaptic transmission at the indirect Schaffer-collateral pathway to CA1 neurons. It is well documented that the hormone leptin regulates many central functions and that hippocampal CA1 pyramidal neurons are a key target for leptin action. Indeed, leptin modulates excitatory synaptic transmission and synaptic plasticity at the Schaffer-collateral input to CA1 neurons. However the impact of leptin on the direct temporoammonic (TA) input to CA1 neurons is not known. Here we show that leptin evokes a long-lasting increase [long-term potentiation (LTP)] in excitatory synaptic transmission at TA-CA1 synapses in rat juvenile hippocampus. Leptin-induced LTP was NMDA receptor-dependent and specifically involved the activation of GluN2B subunits. The signaling pathways underlying leptin-induced LTP involve the activation of phosphoinositide 3-kinase, but were independent of the ERK signaling cascade. Moreover, insertion of GluA2-lacking AMPA receptors was required for leptin-induced LTP as prior application of philanthotoxin prevented the effects of leptin. In addition, synaptic-induced LTP occluded the persistent increase in synaptic efficacy induced by leptin. In conclusion, these data indicate that leptin induces a novel form of NMDA receptor-dependent LTP at juvenile TA-CA1 synapses, which has important implications for the role of leptin in modulating hippocampal synaptic function in health and disease.
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23
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Hansen N, Manahan-Vaughan D. Dopamine D1/D5 receptors mediate informational saliency that promotes persistent hippocampal long-term plasticity. Cereb Cortex 2014; 24:845-58. [PMID: 23183712 PMCID: PMC3948488 DOI: 10.1093/cercor/bhs362] [Citation(s) in RCA: 115] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Dopamine (DA) plays an essential role in the enablement of cognition. It adds color to experience-dependent information storage, conferring salience to the memories that result. At the synaptic level, experience-dependent information storage is enabled by synaptic plasticity, and given its importance for memory formation, it is not surprising that DA comprises a key neuromodulator in the enablement of synaptic plasticity, and particularly of plasticity that persists for longer periods of time: Analogous to long-term memory. The hippocampus, that is a critical structure for the synaptic processing of semantic, episodic, spatial, and declarative memories, is specifically affected by DA, with the D1/D5 receptor proving crucial for hippocampus-dependent memory. Furthermore, D1/D5 receptors are pivotal in conferring the properties of novelty and reward to information being processed by the hippocampus. They also facilitate the expression of persistent forms of synaptic plasticity, and given reports that both long-term potentiation and long-term depression encode different aspects of spatial representations, this suggests that D1/D5 receptors can drive the nature and qualitative content of stored information in the hippocampus. In light of these observations, we propose that D1/D5 receptors gate hippocampal long-term plasticity and memory and are pivotal in conferring the properties of novelty and reward to information being processed by the hippocampus.
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Affiliation(s)
| | - Denise Manahan-Vaughan
- Department of Neurophysiology, Medical Faculty,Ruhr University Bochum, 44780 Bochum, Germany
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24
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Frontal gamma noise power and cognitive domains in schizophrenia. Psychiatry Res 2014; 221:104-13. [PMID: 24300084 DOI: 10.1016/j.pscychresns.2013.11.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Revised: 10/16/2013] [Accepted: 11/09/2013] [Indexed: 01/13/2023]
Abstract
The cognitive deficit profile is different among individuals with schizophrenia. We quantified the amount of electroencephalographic activity unlocked to stimuli onset (noise power) over frontal regions regarding deficit in cognitive domains. Forty-six patients with schizophrenia and 27 healthy controls underwent clinical, cognitive and electrophysiological assessments. Noise power studies may be considered complementary but not equivalent to induced power studies. We compared gamma and theta noise power magnitude during a P300 paradigm between subsets of patients divided according to cognitive deficit in key domains and controls. Patients displayed higher gamma noise power activity at Fz site and significantly lower performance in all cognitive domains when compared to controls. The subset of patients with cognitive deficit for working memory and problem solving/executive functions domains displayed significantly higher frontal-lateral noise power values in comparison to the subset of patients without cognitive deficit and controls. Patients with significant cognitive deficits in domains with greater frontal contribution are also characterized by an abnormally higher gamma band noise power over the frontal region. Our data may endorse various biological subsets within schizophrenia, characterized by the presence or absence of a significant cognitive deficit in frontal domains.
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25
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Hippocampal ether-à-go-go1 potassium channels blockade: Effects in the startle reflex and prepulse inhibition. Neurosci Lett 2014; 559:13-7. [DOI: 10.1016/j.neulet.2013.11.026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 11/13/2013] [Accepted: 11/16/2013] [Indexed: 12/19/2022]
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26
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Aksoy-Aksel A, Manahan-Vaughan D. The temporoammonic input to the hippocampal CA1 region displays distinctly different synaptic plasticity compared to the Schaffer collateral input in vivo: significance for synaptic information processing. Front Synaptic Neurosci 2013; 5:5. [PMID: 23986697 PMCID: PMC3750210 DOI: 10.3389/fnsyn.2013.00005] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Accepted: 08/03/2013] [Indexed: 11/28/2022] Open
Abstract
In terms of its sub-regional differentiation, the hippocampal CA1 region receives cortical information directly via the perforant (temporoammonic) path (pp-CA1 synapse) and indirectly via the tri-synaptic pathway where the last relay station is the Schaffer collateral-CA1 synapse (Sc-CA1 synapse). Research to date on pp-CA1 synapses has been conducted predominantly in vitro and never in awake animals, but these studies hint that information processing at this synapse might be distinct to processing at the Sc-CA1 synapse. Here, we characterized synaptic properties and synaptic plasticity at the pp-CA1 synapse of freely behaving adult rats. We observed that field excitatory postsynaptic potentials at the pp-CA1 synapse have longer onset latencies and a shorter time-to-peak compared to the Sc-CA1 synapse. LTP (>24 h) was successfully evoked by tetanic afferent stimulation of pp-CA1 synapses. Low frequency stimulation evoked synaptic depression at Sc-CA1 synapses, but did not elicit LTD at pp-CA1 synapses unless the Schaffer collateral afferents to the CA1 region had been severed. Paired-pulse responses also showed significant differences. Our data suggest that synaptic plasticity at the pp-CA1 synapse is distinct from the Sc-CA1 synapse and that this may reflect its specific role in hippocampal information processing.
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Affiliation(s)
- Ayla Aksoy-Aksel
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum Bochum, Germany ; International Graduate School for Neuroscience, Ruhr University Bochum Bochum, Germany
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27
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Albrecht MA, Price G, Lee J, Iyyalol R, Martin-Iverson MT. Dexamphetamine selectively increases 40 Hz auditory steady state response power to target and nontarget stimuli in healthy humans. J Psychiatry Neurosci 2013; 38:24-32. [PMID: 22894820 PMCID: PMC3529215 DOI: 10.1503/jpn.110145] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
BACKGROUND An emerging endophenotype of schizophrenia is the reduction of both power and phase locking of the 40 Hz auditory steady state response (ASSR), and there have been a number of reports linking increased γ activity with positive psychotic symptoms. Schizophrenia and, more specifically, positive psychotic symptoms have been closely linked to increased dopamine (DA) neurophysiology. Therefore, we gave dexamphetamine to healthy participants to determine the effect that increased DA transmission would have on the ASSR. METHODS We administered 0.45 mg/kg of dexamphetamine orally in a double-blind placebo-controlled crossover study. Stimuli were 20 Hz and 40 Hz click trains presented in an auditory oddball-type stimulus format (probability of stimulus presentation: 0.2 for targets, 0.8 for nontargets). RESULTS We included 44 healthy volunteers (18 women) in the study. Dexamphetamine significantly increased the 40 Hz power for both target and nontarget ASSR stimuli. Dexamphetamine did not significantly affect the 40 Hz phase-locking factor (PLF) or the 20 Hz power and PLF. Whereas there were significant effects of selective attention on power and PLF for 20 and 40 Hz ASSR, there were no significant interactions between dexamphetamine and selective attention. LIMITATIONS Dexamphetamine releases both noradrenaline and DA with equal potency. Further research with selective dopaminergic and noradrenergic agents will better characterize the effects of monoamines on γ activity. CONCLUSION The results demonstrate a frequency-specific effect of dexamphetamine on the ASSR. This finding is consistent with previous research that has found an association between increased γ and positive symptoms of psychosis. However, this result also raises the possibility that previous 40 Hz ASSR findings in people with schizophrenia may be confounded by effects of antipsychotic medication. Possible neural mechanisms by which dexamphetamine specifically increases 40 Hz power are also discussed. AUSTRALIAN AND NEW ZEALAND CLINICAL TRIALS REGISTRY NUMBER: ACTRN12608000610336.
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Affiliation(s)
- Matthew A. Albrecht
- Correspondence to: M.A. Albrecht, Centre for Clinical Research in Neuropsychiatry, Graylands Hospital, Private Bag No. 1, Claremont WA, 6910, Australia;
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Cutsuridis V. Bursts shape the NMDA-R mediated spike timing dependent plasticity curve: role of burst interspike interval and GABAergic inhibition. Cogn Neurodyn 2012; 6:421-41. [PMID: 24082963 PMCID: PMC3438326 DOI: 10.1007/s11571-012-9205-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Revised: 04/24/2012] [Accepted: 05/02/2012] [Indexed: 11/28/2022] Open
Abstract
Spike timing dependent plasticity (STDP) is a synaptic learning rule where the relative timing between the presynaptic and postsynaptic action potentials determines the sign and strength of synaptic plasticity. In its basic form STDP has an asymmetric form which incorporates both persistent increases and persistent decreases in synaptic strength. The basic form of STDP, however, is not a fixed property and depends on the dendritic location. An asymmetric curve is observed in the distal dendrites, whereas a symmetrical one is observed in the proximal ones. A recent computational study has shown that the transition from the asymmetry to symmetry is due to inhibition under certain conditions. Synapses have also been observed to be unreliable at generating plasticity when excitatory postsynaptic potentials and single spikes are paired at low frequencies. Bursts of spikes, however, are reliably signaled because transmitter release is facilitated. This article presents a two-compartment model of the CA1 pyramidal cell. The model is neurophysiologically plausible with its dynamics resulting from the interplay of many ionic and synaptic currents. Plasticity is measured by a deterministic Ca(2+) dynamics model which measures the instantaneous calcium level and its time course in the dendrite and change the strength of the synapse accordingly. The model is validated to match the asymmetrical form of STDP from the pairing of a presynaptic (dendritic) and postsynaptic (somatic) spikes as observed experimentally. With the parameter set unchanged the model investigates how pairing of bursts with single spikes and bursts in the presence or absence of inhibition shapes the STDP curve. The model predicts that inhibition strength and frequency are not the only factors of the asymmetry-to-symmetry switch of the STDP curve. Burst interspike interval is another factor. This study is an important first step towards understanding how STDP is affected under natural firing patterns in vivo.
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Gangarossa G, Longueville S, De Bundel D, Perroy J, Hervé D, Girault JA, Valjent E. Characterization of dopamine D1 and D2 receptor-expressing neurons in the mouse hippocampus. Hippocampus 2012; 22:2199-207. [DOI: 10.1002/hipo.22044] [Citation(s) in RCA: 100] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/25/2012] [Indexed: 11/06/2022]
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Cutsuridis V, Hasselmo M. GABAergic contributions to gating, timing, and phase precession of hippocampal neuronal activity during theta oscillations. Hippocampus 2012; 22:1597-621. [PMID: 22252986 DOI: 10.1002/hipo.21002] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/17/2011] [Indexed: 12/27/2022]
Abstract
Successful spatial exploration requires gating, storage, and retrieval of spatial memories in the correct order. The hippocampus is known to play an important role in the temporal organization of spatial information. Temporally ordered spatial memories are encoded and retrieved by the firing rate and phase of hippocampal pyramidal cells and inhibitory interneurons with respect to ongoing network theta oscillations paced by intra- and extrahippocampal areas. Much is known about the anatomical, physiological, and molecular characteristics as well as the connectivity and synaptic properties of various cell types in the hippocampal microcircuits, but how these detailed properties of individual neurons give rise to temporal organization of spatial memories remains unclear. We present a model of the hippocampal CA1 microcircuit based on observed biophysical properties of pyramidal cells and six types of inhibitory interneurons: axo-axonic, basket, bistratistified, neurogliaform, ivy, and oriens lacunosum-moleculare cells. The model simulates a virtual rat running on a linear track. Excitatory transient inputs come from the entorhinal cortex (EC) and the CA3 Schaffer collaterals and impinge on both the pyramidal cells and inhibitory interneurons, whereas inhibitory inputs from the medial septum impinge only on the inhibitory interneurons. Dopamine operates as a gate-keeper modulating the spatial memory flow to the PC distal dendrites in a frequency-dependent manner. A mechanism for spike-timing-dependent plasticity in distal and proximal PC dendrites consisting of three calcium detectors, which responds to the instantaneous calcium level and its time course in the dendrite, is used to model the plasticity effects. The model simulates the timing of firing of different hippocampal cell types relative to theta oscillations, and proposes functional roles for the different classes of the hippocampal and septal inhibitory interneurons in the correct ordering of spatial memories as well as in the generation and maintenance of theta phase precession of pyramidal cells (place cells) in CA1. The model leads to a number of experimentally testable predictions that may lead to a better understanding of the biophysical computations in the hippocampus and medial septum.
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Affiliation(s)
- Vassilis Cutsuridis
- Division of Engineering, King's College London, Strand, London, United Kingdom.
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Herwerth M, Jensen V, Novak M, Konopka W, Hvalby O, Köhr G. D4 dopamine receptors modulate NR2B NMDA receptors and LTP in stratum oriens of hippocampal CA1. Cereb Cortex 2011; 22:1786-98. [PMID: 21955919 DOI: 10.1093/cercor/bhr275] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Dopamine plays an important role in synaptic plasticity and learning and is involved in the pathogenesis of various neurological and psychiatric disorders. Here, we reveal staining of dopaminergic fibers in stratum oriens of the mouse hippocampal CA1 region, a finding that is consistent with earlier reports. Furthermore, we examined the effect of dopamine agonists on NMDAR-dependent early long-term potentiation (LTP) (40 min) during γ-aminobutyric acid (GABA)(A)-mediated blockade. LTP of the AMPA component was strongly reduced in stratum oriens but barely affected in stratum radiatum. This layer-specific effect was caused by D4 receptor activation, which augmented the inactivation of synaptic NMDAR-mediated currents (NMDA EPSCs) during LTP induction through a Ca(2+)-dependent G-protein-independent mechanism. A similar dopaminergic modulation of both NMDA EPSCs and LTP was also observed in mice constitutively lacking NR2A but was absent in mice lacking NR2B in principal forebrain neurons. Together, these experiments strongly indicate that dopaminergic modulation of early LTP in stratum oriens occurs through NMDARs containing NR2B subunits via D4Rs. Thus, a dopamine hyperfunction in stratum oriens may result in NMDAR hypofunction that could affect both normal and pathological conditions.
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Affiliation(s)
- Marina Herwerth
- Department of Molecular Neurobiology, Max-Planck-Institute for Medical Research, D-69120 Heidelberg, Germany
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Chu HY, Wu Q, Zhou S, Cao X, Zhang A, Jin GZ, Hu GY, Zhen X. SKF83959 suppresses excitatory synaptic transmission in rat hippocampus via a dopamine receptor-independent mechanism. J Neurosci Res 2011; 89:1259-66. [DOI: 10.1002/jnr.22653] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2010] [Revised: 03/03/2011] [Accepted: 03/04/2011] [Indexed: 01/24/2023]
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Ito HT, Schuman EM. Functional division of hippocampal area CA1 via modulatory gating of entorhinal cortical inputs. Hippocampus 2011; 22:372-87. [PMID: 21240920 DOI: 10.1002/hipo.20909] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/29/2010] [Indexed: 11/11/2022]
Abstract
The hippocampus receives two streams of information, spatial and nonspatial, via major afferent inputs from the medial (MEC) and lateral entorhinal cortexes (LEC). The MEC and LEC projections in the temporoammonic pathway are topographically organized along the transverse-axis of area CA1. The potential for functional segregation of area CA1, however, remains relatively unexplored. Here, we demonstrated differential novelty-induced c-Fos expression along the transverse-axis of area CA1 corresponding to topographic projections of MEC and LEC inputs. We found that, while novel place exposure induced a uniform c-Fos expression along the transverse-axis of area CA1, novel object exposure primarily activated the distal half of CA1 neurons. In hippocampal slices, we observed distinct presynaptic properties between LEC and MEC terminals, and application of either DA or NE produced a largely selective influence on one set of inputs (LEC). Finally, we demonstrated that differential c-Fos expression along the transverse axis of area CA1 was largely abolished by an antagonist of neuromodulatory receptors, clozapine. Our results suggest that neuromodulators can control topographic TA projections allowing the hippocampus to differentially encode new information along the transverse axis of area CA1.
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Affiliation(s)
- Hiroshi T Ito
- Division of Biology, Caltech/HHMI, Pasadena, California, USA
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Abstract
Functional and structural brain imaging has identified neural and neurotransmitter systems involved in schizophrenia and their link to cognitive and behavioural disturbances such as psychosis. Mapping such abnormalities in patients, however, cannot fully capture the strong neurodevelopmental component of schizophrenia that pre-dates manifest illness. A recent strategy to address this issue has been to focus on mechanisms of disease risk. Imaging genetics techniques have made it possible to define neural systems that mediate heritable risk linked to candidate and genome-wide-supported common variants, and mechanisms for environmental risk and gene-environment interactions are emerging. Characterizing the neural risk architecture of schizophrenia provides a translational research strategy for future treatments.
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Abstract
Although the rigorous anatomical definition of the microcircuitry of the brain is essential for understanding its functions, the modulation of the physiological properties of neurons and synapses may confer an additional level of complexity. Here, I review two examples of neuromodulation within a specific microcircuit of the hippocampus, i.e. the local network of stratum lacunosum-moleculare. In particular, I will examine the actions of two different types of neuromodulators on the excitability and electrical coupling of two specific classes of cells. First, I will review the effects of noradrenaline on GABAergic networks. Particular emphasis will be placed on neurogliaform cells. Then, I will describe the chemokinergic modulation of spontaneous firing of Cajal-Retzius cells, mediated by the chemokine (C-X-C motif) ligand 12/stromal cell-derived factor-1 α (CXCL12/SDF-1) via the CXC chemokine receptor 4 (CXCR4). The complexities created by these diverse types of modulations for network activity, together with their potential implications for stratum lacunosum-moleculare processing of information in vivo, will be also presented and briefly discussed.
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Affiliation(s)
- Gianmaria Maccaferri
- Department of Physiology, Feinberg School of Medicine, Northwestern University Medical School, Chicago, IL 60611, USA.
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Ito HT, Smith SEP, Hsiao E, Patterson PH. Maternal immune activation alters nonspatial information processing in the hippocampus of the adult offspring. Brain Behav Immun 2010; 24:930-41. [PMID: 20227486 PMCID: PMC2897971 DOI: 10.1016/j.bbi.2010.03.004] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2010] [Accepted: 03/10/2010] [Indexed: 01/16/2023] Open
Abstract
The observation that maternal infection increases the risk for schizophrenia in the offspring suggests that the maternal immune system plays a key role in the etiology of schizophrenia. In a mouse model, maternal immune activation (MIA) by injection of poly(I:C) yields adult offspring that display abnormalities in a variety of behaviors relevant to schizophrenia. As abnormalities in the hippocampus are a consistent observation in schizophrenia patients, we examined synaptic properties in hippocampal slices prepared from the offspring of poly(I:C)- and saline-treated mothers. Compared to controls, CA1 pyramidal neurons from adult offspring of MIA mothers display reduced frequency and increased amplitude of miniature excitatory postsynaptic currents. In addition, the specific component of the temporoammonic pathway that mediates object-related information displays increased sensitivity to dopamine. To assess hippocampal network function in vivo, we used expression of the immediate-early gene, c-Fos, as a surrogate measure of neuronal activity. Compared to controls, the offspring of poly(I:C)-treated mothers display a distinct c-Fos expression pattern in area CA1 following novel object, but not novel location, exposure. Thus, the offspring of MIA mothers may have an abnormality in modality-specific information processing. Indeed, the MIA offspring display enhanced discrimination in a novel object recognition, but not in an object location, task. Thus, analysis of object and spatial information processing at both synaptic and behavioral levels reveals a largely selective abnormality in object information processing in this mouse model. Our results suggest that altered processing of object-related information may be part of the pathogenesis of schizophrenia-like cognitive behaviors.
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Affiliation(s)
- Hiroshi T. Ito
- Division of Biology, California Institute of Technology, Pasadena, CA 91125
| | | | - Elaine Hsiao
- Division of Biology, California Institute of Technology, Pasadena, CA 91125
| | - Paul H. Patterson
- Division of Biology, California Institute of Technology, Pasadena, CA 91125
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Uhlhaas PJ, Singer W. Abnormal neural oscillations and synchrony in schizophrenia. Nat Rev Neurosci 2010; 11:100-13. [PMID: 20087360 DOI: 10.1038/nrn2774] [Citation(s) in RCA: 1379] [Impact Index Per Article: 98.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Converging evidence from electrophysiological, physiological and anatomical studies suggests that abnormalities in the synchronized oscillatory activity of neurons may have a central role in the pathophysiology of schizophrenia. Neural oscillations are a fundamental mechanism for the establishment of precise temporal relationships between neuronal responses that are in turn relevant for memory, perception and consciousness. In patients with schizophrenia, the synchronization of beta- and gamma-band activity is abnormal, suggesting a crucial role for dysfunctional oscillations in the generation of the cognitive deficits and other symptoms of the disorder. Dysfunctional oscillations may arise owing to anomalies in the brain's rhythm-generating networks of GABA (gamma-aminobutyric acid) interneurons and in cortico-cortical connections.
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Affiliation(s)
- Peter J Uhlhaas
- Department of Neurophysiology, Max-Planck Institute for Brain Research, Frankfurt am Main, 60528, Germany.
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Ito HT, Schuman EM. Frequency-dependent signal transmission and modulation by neuromodulators. Front Neurosci 2008; 2:138-44. [PMID: 19225586 PMCID: PMC2622745 DOI: 10.3389/neuro.01.027.2008] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2008] [Accepted: 11/04/2008] [Indexed: 11/13/2022] Open
Abstract
The brain uses a strategy of labor division, which may allow it to accomplish more elaborate and complicated tasks, but in turn, imposes a requirement for central control to integrate information among different brain areas. Anatomically, the divergence of long-range neuromodulator projections appears well-suited to coordinate communication between brain areas. Oscillatory brain activity is a prominent feature of neural transmission. Thus, the ability of neuromodulators to modulate signal transmission in a frequency-dependent manner adds an additional level of regulation. Here, we review the significance of frequency-dependent signal modulation in brain function and how a neuronal network can possess such properties. We also describe how a neuromodulator, dopamine, changes frequency-dependent signal transmission, controlling information flow from the entorhinal cortex to the hippocampus.
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Affiliation(s)
- Hiroshi T Ito
- Division of Biology, California Institute of Technology Pasadena, CA, USA
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