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Grella SL, Donaldson TN. Contextual memory engrams, and the neuromodulatory influence of the locus coeruleus. Front Mol Neurosci 2024; 17:1342622. [PMID: 38375501 PMCID: PMC10875109 DOI: 10.3389/fnmol.2024.1342622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 01/19/2024] [Indexed: 02/21/2024] Open
Abstract
Here, we review the basis of contextual memory at a conceptual and cellular level. We begin with an overview of the philosophical foundations of traversing space, followed by theories covering the material bases of contextual representations in the hippocampus (engrams), exploring functional characteristics of the cells and subfields within. Next, we explore various methodological approaches for investigating contextual memory engrams, emphasizing plasticity mechanisms. This leads us to discuss the role of neuromodulatory inputs in governing these dynamic changes. We then outline a recent hypothesis involving noradrenergic and dopaminergic projections from the locus coeruleus (LC) to different subregions of the hippocampus, in sculpting contextual representations, giving a brief description of the neuroanatomical and physiological properties of the LC. Finally, we examine how activity in the LC influences contextual memory processes through synaptic plasticity mechanisms to alter hippocampal engrams. Overall, we find that phasic activation of the LC plays an important role in promoting new learning and altering mnemonic processes at the behavioral and cellular level through the neuromodulatory influence of NE/DA in the hippocampus. These findings may provide insight into mechanisms of hippocampal remapping and memory updating, memory processes that are potentially dysregulated in certain psychiatric and neurodegenerative disorders.
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Affiliation(s)
- Stephanie L. Grella
- MNEME Lab, Department of Psychology, Program in Neuroscience, Loyola University Chicago, Chicago, IL, United States
| | - Tia N. Donaldson
- Systems Neuroscience and Behavior Lab, Department of Psychology, The University of New Mexico, Albuquerque, NM, United States
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2
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László BR, Kertes E, Ollmann T, Péczely L, Kovács A, Karádi Z, Lénárd L, László K. The Role of Intra-Amygdaloid Neurotensin and Dopamine Interaction in Spatial Learning and Memory. Biomedicines 2022; 10:biomedicines10123138. [PMID: 36551894 PMCID: PMC9775557 DOI: 10.3390/biomedicines10123138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 11/25/2022] [Accepted: 12/01/2022] [Indexed: 12/12/2022] Open
Abstract
Neurotransmitter and neuromodulator neurotensin (NT) has been proved to facilitate spatial and passive avoidance learning after microinjected into the rat central nucleus of amygdala (CeA). These previous studies of our laboratory also revealed that neurotensin-1 receptor (NTS1) is involved in the mentioned actions of NT. Extensive literature confirms the interaction between neurotensinergic and dopaminergic systems, and our research group also suppose that the mesolimbic dopaminergic system (MLDS) is involved in the spatial learning and memory-facilitating effect of NT in the CeA. In the present work, NT and dopamine (DA) interaction has been examined in the Morris water maze and passive avoidance tests. Rats received 100 ng NT, 5 µg dopamine D2 receptor antagonist sulpiride in itself, sulpiride as a pretreatment before NT or vehicle solution into the CeA. NT microinjection significantly decreased target-finding latency in the Morris water maze test and significantly increased entrance latency in the passive avoidance test, as was expected based on our previous findings. The DA D2 receptor antagonist pretreatment was able to inhibit both effects of NT. The results confirm the facilitatory effect of NT on spatial learning and memory and let us conclude that these actions can be exerted via the DA D2 receptors.
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Affiliation(s)
- Bettina Réka László
- Institute of Physiology, Medical School, University of Pécs, 7602 Pécs, Hungary
- Neuroscience Center, University of Pécs, 7602 Pécs, Hungary
| | - Erika Kertes
- Institute of Physiology, Medical School, University of Pécs, 7602 Pécs, Hungary
- Neuroscience Center, University of Pécs, 7602 Pécs, Hungary
- Learning in Biological and Artificial Systems Research Group, Institute of Physiology, Medical School, University of Pécs, 7602 Pécs, Hungary
- Neuropeptides, Cognition, Animal Models of Neuropsychiatric Disorders Research Group, Institute of Physiology, Medical School, University of Pécs, 7602 Pécs, Hungary
| | - Tamás Ollmann
- Institute of Physiology, Medical School, University of Pécs, 7602 Pécs, Hungary
- Neuroscience Center, University of Pécs, 7602 Pécs, Hungary
- Learning in Biological and Artificial Systems Research Group, Institute of Physiology, Medical School, University of Pécs, 7602 Pécs, Hungary
- Neuropeptides, Cognition, Animal Models of Neuropsychiatric Disorders Research Group, Institute of Physiology, Medical School, University of Pécs, 7602 Pécs, Hungary
| | - László Péczely
- Institute of Physiology, Medical School, University of Pécs, 7602 Pécs, Hungary
- Neuroscience Center, University of Pécs, 7602 Pécs, Hungary
- Learning in Biological and Artificial Systems Research Group, Institute of Physiology, Medical School, University of Pécs, 7602 Pécs, Hungary
| | - Anita Kovács
- Institute of Physiology, Medical School, University of Pécs, 7602 Pécs, Hungary
- Neuroscience Center, University of Pécs, 7602 Pécs, Hungary
- Neuropeptides, Cognition, Animal Models of Neuropsychiatric Disorders Research Group, Institute of Physiology, Medical School, University of Pécs, 7602 Pécs, Hungary
| | - Zoltán Karádi
- Institute of Physiology, Medical School, University of Pécs, 7602 Pécs, Hungary
- Neuroscience Center, University of Pécs, 7602 Pécs, Hungary
- Szentágothai Research Center, Cellular Bioimpedance Research Group, 7624 Pécs, Hungary
- Szentágothai Center, Molecular Endocrinology and Neurophysiology Research Group, University of Pécs, 7624 Pécs, Hungary
| | - László Lénárd
- Institute of Physiology, Medical School, University of Pécs, 7602 Pécs, Hungary
- Neuroscience Center, University of Pécs, 7602 Pécs, Hungary
- Szentágothai Research Center, Cellular Bioimpedance Research Group, 7624 Pécs, Hungary
- Szentágothai Center, Molecular Endocrinology and Neurophysiology Research Group, University of Pécs, 7624 Pécs, Hungary
| | - Kristóf László
- Institute of Physiology, Medical School, University of Pécs, 7602 Pécs, Hungary
- Neuroscience Center, University of Pécs, 7602 Pécs, Hungary
- Neuropeptides, Cognition, Animal Models of Neuropsychiatric Disorders Research Group, Institute of Physiology, Medical School, University of Pécs, 7602 Pécs, Hungary
- Correspondence:
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3
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Anastasiades PG, de Vivo L, Bellesi M, Jones MW. Adolescent sleep and the foundations of prefrontal cortical development and dysfunction. Prog Neurobiol 2022; 218:102338. [PMID: 35963360 DOI: 10.1016/j.pneurobio.2022.102338] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 08/04/2022] [Accepted: 08/08/2022] [Indexed: 11/17/2022]
Abstract
Modern life poses many threats to good-quality sleep, challenging brain health across the lifespan. Curtailed or fragmented sleep may be particularly damaging during adolescence, when sleep disruption by delayed chronotypes and societal pressures coincides with our brains preparing for adult life via intense refinement of neural connectivity. These vulnerabilities converge on the prefrontal cortex, one of the last brain regions to mature and a central hub of the limbic-cortical circuits underpinning decision-making, reward processing, social interactions and emotion. Even subtle disruption of prefrontal cortical development during adolescence may therefore have enduring impact. In this review, we integrate synaptic and circuit mechanisms, glial biology, sleep neurophysiology and epidemiology, to frame a hypothesis highlighting the implications of adolescent sleep disruption for the neural circuitry of the prefrontal cortex. Convergent evidence underscores the importance of acknowledging, quantifying and optimizing adolescent sleep's contributions to normative brain development and to lifelong mental health.
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Affiliation(s)
- Paul G Anastasiades
- University of Bristol, Translational Health Sciences, Dorothy Hodgkin Building, Whitson Street, Bristol BS1 3NY, UK
| | - Luisa de Vivo
- University of Bristol, School of Physiology, Pharmacology & Neuroscience, University Walk, Bristol BS8 1TD, UK; University of Camerino, School of Pharmacy, via Gentile III Da Varano, Camerino 62032, Italy
| | - Michele Bellesi
- University of Bristol, School of Physiology, Pharmacology & Neuroscience, University Walk, Bristol BS8 1TD, UK; University of Camerino, School of Bioscience and Veterinary Medicine, via Gentile III Da Varano, Camerino 62032, Italy
| | - Matt W Jones
- University of Bristol, School of Physiology, Pharmacology & Neuroscience, University Walk, Bristol BS8 1TD, UK
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4
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Heruye SH, Warren TJ, Kostansek IV JA, Draves SB, Matthews SA, West PJ, Simeone KA, Simeone TA. Ascorbic Acid Reduces Neurotransmission, Synaptic Plasticity, and Spontaneous Hippocampal Rhythms in In Vitro Slices. Nutrients 2022; 14:nu14030613. [PMID: 35276972 PMCID: PMC8839482 DOI: 10.3390/nu14030613] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 01/27/2022] [Accepted: 01/28/2022] [Indexed: 12/26/2022] Open
Abstract
Ascorbic acid (AA; a.k.a. vitamin C) is well known for its cellular protection in environments of high oxidative stress. Even though physiological concentrations of AA in the brain are significant (0.2–10 mM), surprisingly little is known concerning the role of AA in synaptic neurotransmission under normal, non-disease state conditions. Here, we examined AA effects on neurotransmission, plasticity and spontaneous network activity (i.e., sharp waves and high frequency oscillations; SPW-HFOs), at the synapse between area 3 and 1 of the hippocampal cornu ammonis region (CA3 and CA1) using an extracellular multi-electrode array in in vitro mouse hippocampal slices. We found that AA decreased evoked field potentials (fEPSPs, IC50 = 0.64 mM) without affecting V50s or paired pulse facilitation indicating normal neurotransmitter release mechanisms. AA decreased presynaptic fiber volleys but did not change fiber volley-to-fEPSP coupling, suggesting reduced fEPSPs resulted from decreased fiber volleys. Inhibitory effects were also observed in CA1 stratum pyramidale where greater fEPSPs were required for population spikes in the presence of AA suggesting an impact on the intrinsic excitability of neurons. Other forms of synaptic plasticity and correlates of memory (i.e., short- and long-term potentiation) were also significantly reduced by AA as was the incidence of spontaneous SPW-HFOs. AA decreased SPW amplitude with a similar IC50 as fEPSPs (0.65 mM). Overall, these results indicate that under normal conditions AA significantly regulates neurotransmission, plasticity, and network activity by limiting excitability. Thus, AA may participate in refinement of signal processing and memory formation, as well as protecting against pathologic excitability.
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Affiliation(s)
- Segewkal H. Heruye
- Department of Pharmacology & Neuroscience, School of Medicine, Creighton University, Omaha, NE 68174, USA; (S.H.H.); (T.J.W.); (J.A.K.IV); (S.B.D.); (S.A.M.); (K.A.S.)
| | - Ted J. Warren
- Department of Pharmacology & Neuroscience, School of Medicine, Creighton University, Omaha, NE 68174, USA; (S.H.H.); (T.J.W.); (J.A.K.IV); (S.B.D.); (S.A.M.); (K.A.S.)
| | - Joseph A. Kostansek IV
- Department of Pharmacology & Neuroscience, School of Medicine, Creighton University, Omaha, NE 68174, USA; (S.H.H.); (T.J.W.); (J.A.K.IV); (S.B.D.); (S.A.M.); (K.A.S.)
| | - Samantha B. Draves
- Department of Pharmacology & Neuroscience, School of Medicine, Creighton University, Omaha, NE 68174, USA; (S.H.H.); (T.J.W.); (J.A.K.IV); (S.B.D.); (S.A.M.); (K.A.S.)
| | - Stephanie A. Matthews
- Department of Pharmacology & Neuroscience, School of Medicine, Creighton University, Omaha, NE 68174, USA; (S.H.H.); (T.J.W.); (J.A.K.IV); (S.B.D.); (S.A.M.); (K.A.S.)
| | - Peter J. West
- Department of Pharmacology & Toxicology, College of Pharmacy, University of Utah, Salt Lake City, UT 84112, USA;
| | - Kristina A. Simeone
- Department of Pharmacology & Neuroscience, School of Medicine, Creighton University, Omaha, NE 68174, USA; (S.H.H.); (T.J.W.); (J.A.K.IV); (S.B.D.); (S.A.M.); (K.A.S.)
| | - Timothy A. Simeone
- Department of Pharmacology & Neuroscience, School of Medicine, Creighton University, Omaha, NE 68174, USA; (S.H.H.); (T.J.W.); (J.A.K.IV); (S.B.D.); (S.A.M.); (K.A.S.)
- Correspondence:
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5
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Ruggiero RN, Rossignoli MT, Marques DB, de Sousa BM, Romcy-Pereira RN, Lopes-Aguiar C, Leite JP. Neuromodulation of Hippocampal-Prefrontal Cortical Synaptic Plasticity and Functional Connectivity: Implications for Neuropsychiatric Disorders. Front Cell Neurosci 2021; 15:732360. [PMID: 34707481 PMCID: PMC8542677 DOI: 10.3389/fncel.2021.732360] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 09/01/2021] [Indexed: 01/11/2023] Open
Abstract
The hippocampus-prefrontal cortex (HPC-PFC) pathway plays a fundamental role in executive and emotional functions. Neurophysiological studies have begun to unveil the dynamics of HPC-PFC interaction in both immediate demands and long-term adaptations. Disruptions in HPC-PFC functional connectivity can contribute to neuropsychiatric symptoms observed in mental illnesses and neurological conditions, such as schizophrenia, depression, anxiety disorders, and Alzheimer's disease. Given the role in functional and dysfunctional physiology, it is crucial to understand the mechanisms that modulate the dynamics of HPC-PFC communication. Two of the main mechanisms that regulate HPC-PFC interactions are synaptic plasticity and modulatory neurotransmission. Synaptic plasticity can be investigated inducing long-term potentiation or long-term depression, while spontaneous functional connectivity can be inferred by statistical dependencies between the local field potentials of both regions. In turn, several neurotransmitters, such as acetylcholine, dopamine, serotonin, noradrenaline, and endocannabinoids, can regulate the fine-tuning of HPC-PFC connectivity. Despite experimental evidence, the effects of neuromodulation on HPC-PFC neuronal dynamics from cellular to behavioral levels are not fully understood. The current literature lacks a review that focuses on the main neurotransmitter interactions with HPC-PFC activity. Here we reviewed studies showing the effects of the main neurotransmitter systems in long- and short-term HPC-PFC synaptic plasticity. We also looked for the neuromodulatory effects on HPC-PFC oscillatory coordination. Finally, we review the implications of HPC-PFC disruption in synaptic plasticity and functional connectivity on cognition and neuropsychiatric disorders. The comprehensive overview of these impairments could help better understand the role of neuromodulation in HPC-PFC communication and generate insights into the etiology and physiopathology of clinical conditions.
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Affiliation(s)
- Rafael Naime Ruggiero
- Department of Neuroscience and Behavioral Sciences, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Matheus Teixeira Rossignoli
- Department of Neuroscience and Behavioral Sciences, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Danilo Benette Marques
- Department of Neuroscience and Behavioral Sciences, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Bruno Monteiro de Sousa
- Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | | | - Cleiton Lopes-Aguiar
- Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - João Pereira Leite
- Department of Neuroscience and Behavioral Sciences, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
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6
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Zhen ZH, Guo MR, Li HM, Guo OY, Zhen JL, Fu J, Tan GJ. Normal and Abnormal Sharp Wave Ripples in the Hippocampal-Entorhinal Cortex System: Implications for Memory Consolidation, Alzheimer's Disease, and Temporal Lobe Epilepsy. Front Aging Neurosci 2021; 13:683483. [PMID: 34262446 PMCID: PMC8273653 DOI: 10.3389/fnagi.2021.683483] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Accepted: 06/01/2021] [Indexed: 12/14/2022] Open
Abstract
The appearance of hippocampal sharp wave ripples (SWRs) is an electrophysiological biomarker for episodic memory encoding and behavioral planning. Disturbed SWRs are considered a sign of neural network dysfunction that may provide insights into the structural connectivity changes associated with cognitive impairment in early-stage Alzheimer's disease (AD) and temporal lobe epilepsy (TLE). SWRs originating from hippocampus have been extensively studied during spatial navigation in rodents, and more recent studies have investigated SWRs in the hippocampal-entorhinal cortex (HPC-EC) system during a variety of other memory-guided behaviors. Understanding how SWR disruption impairs memory function, especially episodic memory, could aid in the development of more efficacious therapeutics for AD and TLE. In this review, we first provide an overview of the reciprocal association between AD and TLE, and then focus on the functions of HPC-EC system SWRs in episodic memory consolidation. It is posited that these waveforms reflect rapid network interactions among excitatory projection neurons and local interneurons and that these waves may contribute to synaptic plasticity underlying memory consolidation. Further, SWRs appear altered or ectopic in AD and TLE. These waveforms may thus provide clues to understanding disease pathogenesis and may even serve as biomarkers for early-stage disease progression and treatment response.
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Affiliation(s)
- Zhi-Hang Zhen
- Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, China
| | - Mo-Ran Guo
- Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, China.,Neurological Laboratory of Hebei Province, Shijiazhuang, China
| | - He-Ming Li
- Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, China
| | - Ou-Yang Guo
- Department of Biology, Boston University, Boston, MA, United States
| | - Jun-Li Zhen
- Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, China.,Neurological Laboratory of Hebei Province, Shijiazhuang, China
| | - Jian Fu
- Department of Emergency Surgery, The Second Hospital of Hebei Medical University, Shijiazhuang, China
| | - Guo-Jun Tan
- Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, China.,Neurological Laboratory of Hebei Province, Shijiazhuang, China
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7
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O'Callaghan C, Walpola IC, Shine JM. Neuromodulation of the mind-wandering brain state: the interaction between neuromodulatory tone, sharp wave-ripples and spontaneous thought. Philos Trans R Soc Lond B Biol Sci 2020; 376:20190699. [PMID: 33308063 DOI: 10.1098/rstb.2019.0699] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Mind-wandering has become a captivating topic for cognitive neuroscientists. By now, it is reasonably well described in terms of its phenomenology and the large-scale neural networks that support it. However, we know very little about what neurobiological mechanisms trigger a mind-wandering episode and sustain the mind-wandering brain state. Here, we focus on the role of ascending neuromodulatory systems (i.e. acetylcholine, noradrenaline, serotonin and dopamine) in shaping mind-wandering. We advance the hypothesis that the hippocampal sharp wave-ripple (SWR) is a compelling candidate for a brain state that can trigger mind-wandering episodes. This hippocampal rhythm, which occurs spontaneously in quiescent behavioural states, is capable of propagating widespread activity in the default network and is functionally associated with recollective, associative, imagination and simulation processes. The occurrence of the SWR is heavily dependent on hippocampal neuromodulatory tone. We describe how the interplay of neuromodulators may promote the hippocampal SWR and trigger mind-wandering episodes. We then identify the global neuromodulatory signatures that shape the evolution of the mind-wandering brain state. Under our proposed framework, mind-wandering emerges due to the interplay between neuromodulatory systems that influence the transitions between brain states, which either facilitate, or impede, a wandering mind. This article is part of the theme issue 'Offline perception: voluntary and spontaneous perceptual experiences without matching external stimulation'.
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Affiliation(s)
- Claire O'Callaghan
- Brain and Mind Centre and School of Medical Sciences, Faculty of Medicine, University of Sydney, Sydney, Australia.,Department of Psychiatry, University of Cambridge, Cambridge, UK
| | - Ishan C Walpola
- Brain and Mind Centre and School of Medical Sciences, Faculty of Medicine, University of Sydney, Sydney, Australia
| | - James M Shine
- Brain and Mind Centre and School of Medical Sciences, Faculty of Medicine, University of Sydney, Sydney, Australia
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8
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Liu L, Zhou X, Wu JY. Preparing Viable Hippocampal Slices from Adult Mice for the Study of Sharp Wave-ripples. Bio Protoc 2020; 10:e3771. [PMID: 33659429 DOI: 10.21769/bioprotoc.3771] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 07/26/2020] [Accepted: 07/28/2020] [Indexed: 11/02/2022] Open
Abstract
We describe a protocol for preparing acute brain slices which can produce robust hippocampal sharp wave-ripples (SWRs) in vitro. The protocol is optimized for its simplicity and reliability for the preparation of solutions, slicing, and recovery incubation. Most slices in almost every mouse prepared though the protocol expressed vigorous spontaneous SWRs for ~24 h, compared to the 20-30% viability from "standard" low sodium slicing protocols. SWRs are spontaneous neuronal activity in the hippocampus and are essential for consolidation of episodic memory. Brain slices reliably expressing SWRs are useful for studying memory impairment and brain degeneration diseases in ex vivo experiments. Spontaneous expression of SWRs is sensitive to conditions of slicing and perfusion/oxygenation during recording. The amplitude and abundance of SWRs are often used as a biomarker for viable slices. Key improvements include fast circulation, a long recovery period (3-6 h) after slicing, and allowing tissue to recover at 32 °C in a well perfused incubation chamber. Slices in our custom-made apparatus can express spontaneous SWRs for many hours, suggesting a long period with balanced excitation and inhibition in the local networks. Slices from older mice (~postnatal 180 days) show similar viability to younger (postnatal 21-30) mice.
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Affiliation(s)
- Linhua Liu
- Department of Neuroscience, Georgetown University Medical center, Washington DC, 20007, USA.,Department of Environmental and Occupational Health, School of Public Health, Guangdong Medical University, Dongguan 523808, PR China
| | - Xiaojing Zhou
- Department of Neuroscience, Georgetown University Medical center, Washington DC, 20007, USA.,Biotechnology Program, Georgetown University Medical Center, USA
| | - Jian-Young Wu
- Department of Neuroscience, Georgetown University Medical center, Washington DC, 20007, USA
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Gao F, Luo J, Song Y, He E, Zhang Y, Xiao G, Cai X. Microelectrode arrays for monitoring neural activity in neural stem cells with modulation by glutamate in vitro. Nanotechnology and Precision Engineering 2020; 3:69-74. [DOI: 10.1016/j.npe.2020.03.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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10
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Caccavano A, Bozzelli PL, Forcelli PA, Pak DTS, Wu JY, Conant K, Vicini S. Inhibitory Parvalbumin Basket Cell Activity is Selectively Reduced during Hippocampal Sharp Wave Ripples in a Mouse Model of Familial Alzheimer's Disease. J Neurosci 2020; 40:5116-36. [PMID: 32439703 DOI: 10.1523/JNEUROSCI.0425-20.2020] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 05/07/2020] [Accepted: 05/18/2020] [Indexed: 12/29/2022] Open
Abstract
Memory disruption in mild cognitive impairment (MCI) and Alzheimer's disease (AD) is poorly understood, particularly at early stages preceding neurodegeneration. In mouse models of AD, there are disruptions to sharp wave ripples (SWRs), hippocampal population events with a critical role in memory consolidation. However, the microcircuitry underlying these disruptions is under-explored. We tested whether a selective reduction in parvalbumin-expressing (PV) inhibitory interneuron activity underlies hyperactivity and SWR disruption. We employed the 5xFAD model of familial AD crossed with mouse lines labeling excitatory pyramidal cells (PCs) and inhibitory PV cells. We observed a 33% increase in frequency, 58% increase in amplitude, and 8% decrease in duration of SWRs in ex vivo slices from male and female three-month 5xFAD mice versus littermate controls. 5xFAD mice of the same age were impaired in a hippocampal-dependent memory task. Concurrent with SWR recordings, we performed calcium imaging, cell-attached, and whole-cell recordings of PC and PV cells within the CA1 region. PCs in 5xFAD mice participated in enlarged ensembles, with superficial PCs (sPCs) having a higher probability of spiking during SWRs. Both deep PCs (dPCs) and sPCs displayed an increased synaptic E/I ratio, suggesting a disinhibitory mechanism. In contrast, we observed a 46% spike rate reduction during SWRs in PV basket cells (PVBCs), while PV bistratified and axo-axonic cells were unimpaired. Excitatory synaptic drive to PVBCs was selectively reduced by 50%, resulting in decreased E/I ratio. Considering prior studies of intrinsic PV cell dysfunction in AD, these findings suggest alterations to the PC-PVBC microcircuit also contribute to impairment.SIGNIFICANCE STATEMENT We demonstrate that a specific subtype of inhibitory neuron, parvalbumin-expressing (PV) basket cells, have selectively reduced activity in a model of Alzheimer's disease (AD) during activity critical for the consolidation of memory. These results identify a potential cellular target for therapeutic intervention to restore aberrant network activity in early amyloid pathology. While PV cells have previously been identified as a potential therapeutic target, this study for the first time recognizes that other PV neuronal subtypes, including bistratified and axo-axonic cells, are spared. These experiments are the first to record synaptic and spiking activity during sharp wave ripple (SWR) events in early amyloid pathology and reveal that a selective decrease in excitatory synaptic drive to PV basket cells (PVBCs) likely underlies reduced function.
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Li P, Geng X, Jiang H, Caccavano A, Vicini S, Wu JY. Measuring Sharp Waves and Oscillatory Population Activity With the Genetically Encoded Calcium Indicator GCaMP6f. Front Cell Neurosci 2019; 13:274. [PMID: 31275115 PMCID: PMC6593119 DOI: 10.3389/fncel.2019.00274] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 06/05/2019] [Indexed: 12/16/2022] Open
Abstract
GCaMP6f is among the most widely used genetically encoded calcium indicators for monitoring neuronal activity. Applications are at both the cellular and population levels. Here, we explore two important and under-explored issues. First, we have tested if GCaMP6f is sensitive enough for the detection of population activity with sparse firing, similar to the sensitivity of the local field potential (LFP). Second, we have tested if GCaMP6f is fast enough for the detection of fast network oscillations critical for the encoding and consolidation of memory. We have focused this study on the activity of the hippocampal network including sharp waves (SWs), carbachol-induced theta oscillations, and interictal-like spikes. We compare simultaneous LFP and optical GCaMP6f fluorescent recordings in Thy1-GCaMP6f mouse hippocampal slices. We observe that SWs produce a clear population GCaMP6f signal above noise with an average magnitude of 0.3% ΔF/F. This population signal is highly correlated with the LFP, albeit with a delay of 40.3 ms (SD 10.8 ms). The population GCaMP6f signal follows the LFP evoked by 20 Hz stimulation with high fidelity, while electrically evoked oscillations up to 40 Hz were detectable with reduced amplitude. GCaMP6f and LFP signals showed a large amplitude discrepancy. The amplitude of GCaMP6f fluorescence increased by a factor of 28.9 (SD 13.5) between spontaneous SWs and carbachol-induced theta bursts, while the LFP amplitude increased by a factor of 2.4 (SD 1.0). Our results suggest that GCaMP6f is a useful tool for applications commonly considered beyond the scope of genetically encoded calcium indicators. In particular, population GCaMP6f signals are sensitive enough for detecting synchronous network events with sparse firing and sub-threshold activity, as well as asynchronous events with only a nominal LFP. In addition, population GCaMP6f signals are fast enough for monitoring theta and beta oscillations (<25 Hz). Faster calcium indicators (e.g., GCaMP7) will further improve the frequency response for the detection of gamma band oscillations. The advantage of population optical over LFP recordings are that they are non-contact and free from stimulation artifacts. These features may be particularly useful for high-throughput recordings and applications sensitive to stimulus artifact, such as monitoring responses during continuous stimulation.
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Affiliation(s)
- Pinggan Li
- Department of Pediatric Neurology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
- Department of Neuroscience, Georgetown University, Washington, DC, United States
| | - Xinling Geng
- Department of Neuroscience, Georgetown University, Washington, DC, United States
- School of Biomedical Engineering, Capital Medical University, Beijing, China
| | - Huiyi Jiang
- Department of Neuroscience, Georgetown University, Washington, DC, United States
- Department of Pediatrics, The First Hospital of Jilin University, Changchun, China
| | - Adam Caccavano
- Department of Pharmacology and Physiology, Georgetown University, Washington, DC, United States
| | - Stefano Vicini
- Department of Pharmacology and Physiology, Georgetown University, Washington, DC, United States
| | - Jian-young Wu
- Department of Neuroscience, Georgetown University, Washington, DC, United States
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12
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Duszkiewicz AJ, McNamara CG, Takeuchi T, Genzel L. Novelty and Dopaminergic Modulation of Memory Persistence: A Tale of Two Systems. Trends Neurosci 2018; 42:102-114. [PMID: 30455050 PMCID: PMC6352318 DOI: 10.1016/j.tins.2018.10.002] [Citation(s) in RCA: 149] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 09/26/2018] [Accepted: 10/01/2018] [Indexed: 11/10/2022]
Abstract
Adaptation to the ever-changing world is critical for survival, and our brains are particularly tuned to remember events that differ from previous experiences. Novel experiences induce dopamine release in the hippocampus, a process which promotes memory persistence. While axons from the ventral tegmental area (VTA) were generally thought to be the exclusive source of hippocampal dopamine, recent studies have demonstrated that noradrenergic neurons in the locus coeruleus (LC) corelease noradrenaline and dopamine in the hippocampus and that their dopamine release boosts memory retention as well. In this opinion article, we propose that the projections originating from the VTA and the LC belong to two distinct systems that enhance memory of novel events. Novel experiences that share some commonality with past ones (‘common novelty’) activate the VTA and promote semantic memory formation via systems memory consolidation. By contrast, experiences that bear only a minimal relationship to past experiences (‘distinct novelty’) activate the LC to trigger strong initial memory consolidation in the hippocampus, resulting in vivid and long-lasting episodic memories. Novelty induces dopamine release in the hippocampus, triggering memory consolidation to boost memory persistence. Two dopaminergic systems (the ventral tegmental area- and locus coeruleus-hippocampus systems) can stabilise memory through novelty-induced dopamine release in the hippocampus. Novel experiences can be viewed as a spectrum, from experiences that, while clearly novel, share some commonality with past experiences (‘common novelty’), to more fundamentally distinct experiences that bear minimal relationships to past experiences (‘distinct novelty’). We propose that events characterised by ‘common novelty’ boost memory retention via activation of the ventral tegmental area-hippocampus system, resulting in initial consolidation followed by systems consolidation to create neocortical, semantic, long-term memories. We further propose that events characterised by ‘distinct novelty’ lead to the boost of detailed hippocampal, episodic, long-term memory via activation of the locus coeruleus-hippocampus system through strong upregulation of the synaptic tagging and capture mechanism.
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Affiliation(s)
- Adrian J Duszkiewicz
- Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada; Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Colin G McNamara
- MRC Brain Network Dynamics Unit, Department of Pharmacology, University of Oxford, Oxford, UK
| | - Tomonori Takeuchi
- Danish Research Institute of Translational Neuroscience (DANDRITE), Nordic-EMBL Partnership for Molecular Medicine, Aarhus University, Aarhus, Denmark; Department of Biomedicine, Aarhus University, Aarhus, Denmark; Aarhus Institute of Advanced Studies (AIAS), Aarhus University, Aarhus, Denmark.
| | - Lisa Genzel
- Donders Institute for Brain, Cognition, and Behaviour, Radboud University and Radboudumc, Nijmegen, The Netherlands.
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13
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Lupica CR, Hoffman AF. Cannabinoid disruption of learning mechanisms involved in reward processing. ACTA ACUST UNITED AC 2018; 25:435-445. [PMID: 30115765 PMCID: PMC6097761 DOI: 10.1101/lm.046748.117] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 07/06/2018] [Indexed: 02/06/2023]
Abstract
The increasing use of cannabis, its derivatives, and synthetic cannabinoids for medicinal and recreational purposes has led to burgeoning interest in understanding the addictive potential of this class of molecules. It is estimated that ∼10% of marijuana users will eventually show signs of dependence on the drug, and the diagnosis of cannabis use disorder (CUD) is increasing in the United States. The molecule that sustains the use of cannabis is Δ9-tetrahydrocannabinol (Δ9-THC), and our knowledge of its effects, and those of other cannabinoids on brain function has expanded rapidly in the past two decades. Additionally, the identification of endogenous cannabinoid (endocannabinoid) systems in brain and their roles in physiology and behavior, demonstrate extensive involvement of these lipid signaling molecules in regulating CNS function. Here, we examine roles for endogenous cannabinoids in shaping synaptic activity in cortical and subcortical brain circuits, and we discuss mechanisms in which exogenous cannabinoids, such as Δ9-THC, interact with endocannabinoid systems to disrupt neuronal network oscillations. We then explore how perturbation of the interaction of this activity within brain reward circuits may lead to impaired learning. Finally, we propose that disruption of cellular plasticity mechanisms by exogenous cannabinoids in cortical and subcortical circuits may explain the difficulty in establishing viable cannabinoid self-administration models in animals.
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Affiliation(s)
- Carl R Lupica
- Electrophysiology Research Section, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, Maryland 21224, USA
| | - Alexander F Hoffman
- Electrophysiology Research Section, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, Maryland 21224, USA
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14
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Abstract
Neural networks, including the respiratory network, can undergo a reconfiguration process by just changing the number, the connectivity or the activity of their elements. Those elements can be either brain regions or neurons, which constitute the building blocks of macrocircuits and microcircuits, respectively. The reconfiguration processes can also involve changes in the number of connections and/or the strength between the elements of the network. These changes allow neural networks to acquire different topologies to perform a variety of functions or change their responses as a consequence of physiological or pathological conditions. Thus, neural networks are not hardwired entities, but they constitute flexible circuits that can be constantly reconfigured in response to a variety of stimuli. Here, we are going to review several examples of these processes with special emphasis on the reconfiguration of the respiratory rhythm generator in response to different patterns of hypoxia, which can lead to changes in respiratory patterns or lasting changes in frequency and/or amplitude.
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Affiliation(s)
- Fernando Peña-Ortega
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, Universidad Nacional Autónoma de México, UNAM-Campus Juriquilla, Boulevard Juriquilla 3001, Querétaro, 76230, Mexico.
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15
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Parrilla-Carrero J, Buchta WC, Goswamee P, Culver O, McKendrick G, Harlan B, Moutal A, Penrod R, Lauer A, Ramakrishnan V, Khanna R, Kalivas P, Riegel AC. Restoration of Kv7 Channel-Mediated Inhibition Reduces Cued-Reinstatement of Cocaine Seeking. J Neurosci 2018; 38:4212-4229. [PMID: 29636392 PMCID: PMC5963852 DOI: 10.1523/jneurosci.2767-17.2018] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2017] [Revised: 03/27/2018] [Accepted: 03/29/2018] [Indexed: 12/16/2022] Open
Abstract
Cocaine addicts display increased sensitivity to drug-associated cues, due in part to changes in the prelimbic prefrontal cortex (PL-PFC). The cellular mechanisms underlying cue-induced reinstatement of cocaine seeking remain unknown. Reinforcement learning for addictive drugs may produce persistent maladaptations in intrinsic excitability within sparse subsets of PFC pyramidal neurons. Using a model of relapse in male rats, we sampled >600 neurons to examine spike frequency adaptation (SFA) and afterhyperpolarizations (AHPs), two systems that attenuate low-frequency inputs to regulate neuronal synchronization. We observed that training to self-administer cocaine or nondrug (sucrose) reinforcers decreased SFA and AHPs in a subpopulation of PL-PFC neurons. Only with cocaine did the resulting hyperexcitability persist through extinction training and increase during reinstatement. In neurons with intact SFA, dopamine enhanced excitability by inhibiting Kv7 potassium channels that mediate SFA. However, dopamine effects were occluded in neurons from cocaine-experienced rats, where SFA and AHPs were reduced. Pharmacological stabilization of Kv7 channels with retigabine restored SFA and Kv7 channel function in neuroadapted cells. When microinjected bilaterally into the PL-PFC 10 min before reinstatement testing, retigabine reduced cue-induced reinstatement of cocaine seeking. Last, using cFos-GFP transgenic rats, we found that the loss of SFA correlated with the expression of cFos-GFP following both extinction and re-exposure to drug-associated cues. Together, these data suggest that cocaine self-administration desensitizes inhibitory Kv7 channels in a subpopulation of PL-PFC neurons. This subpopulation of neurons may represent a persistent neural ensemble responsible for driving drug seeking in response to cues.SIGNIFICANCE STATEMENT Long after the cessation of drug use, cues associated with cocaine still elicit drug-seeking behavior, in part by activation of the prelimbic prefrontal cortex (PL-PFC). The underlying cellular mechanisms governing these activated neurons remain unclear. Using a rat model of relapse to cocaine seeking, we identified a population of PL-PFC neurons that become hyperexcitable following chronic cocaine self-administration. These neurons show persistent loss of spike frequency adaptation, reduced afterhyperpolarizations, decreased sensitivity to dopamine, and reduced Kv7 channel-mediated inhibition. Stabilization of Kv7 channel function with retigabine normalized neuronal excitability, restored Kv7 channel currents, and reduced drug-seeking behavior when administered into the PL-PFC before reinstatement. These data highlight a persistent adaptation in a subset of PL-PFC neurons that may contribute to relapse vulnerability.
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Affiliation(s)
- Jeffrey Parrilla-Carrero
- Department of Neuroscience
- Neurobiology of Addiction Research Center, Medical University of South Carolina, Charleston, South Carolina 29425
| | - William C Buchta
- Department of Neuroscience
- Neurobiology of Addiction Research Center, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Priyodarshan Goswamee
- Department of Neuroscience
- Neurobiology of Addiction Research Center, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Oliver Culver
- Department of Neuroscience
- Neurobiology of Addiction Research Center, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Greer McKendrick
- Department of Neuroscience
- Neurobiology of Addiction Research Center, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Benjamin Harlan
- Department of Neuroscience
- Neurobiology of Addiction Research Center, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Aubin Moutal
- Department of Pharmacology, University of Arizona, Tucson, Arizona 85724, and
| | - Rachel Penrod
- Department of Neuroscience
- Neurobiology of Addiction Research Center, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Abigail Lauer
- Department of Public Health Sciences., Medical University of South Carolina, Charleston, SC 29425
| | - Viswanathan Ramakrishnan
- Department of Public Health Sciences., Medical University of South Carolina, Charleston, SC 29425
| | - Rajesh Khanna
- Department of Pharmacology, University of Arizona, Tucson, Arizona 85724, and
| | - Peter Kalivas
- Department of Neuroscience
- Neurobiology of Addiction Research Center, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Arthur C Riegel
- Department of Neuroscience,
- Neurobiology of Addiction Research Center, Medical University of South Carolina, Charleston, South Carolina 29425
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16
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Jiang H, Liu S, Geng X, Caccavano A, Conant K, Vicini S, Wu J. Pacing Hippocampal Sharp-Wave Ripples With Weak Electric Stimulation. Front Neurosci 2018; 12:164. [PMID: 29599704 PMCID: PMC5862867 DOI: 10.3389/fnins.2018.00164] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 02/28/2018] [Indexed: 11/13/2022] Open
Abstract
Sharp-wave ripples (SWRs) are spontaneous neuronal population events that occur in the hippocampus during sleep and quiet restfulness, and are thought to play a critical role in the consolidation of episodic memory. SWRs occur at a rate of 30-200 events per minute. Their overall abundance may, however, be reduced with aging and neurodegenerative disease. Here we report that the abundance of SWR within murine hippocampal slices can be increased by paced administration of a weak electrical stimulus, especially when the spontaneously occurring rate is low or compromised. Resultant SWRs have large variations in amplitude and ripple patterns, which are morphologically indistinguishable from those of spontaneous SWRs, despite identical stimulus parameters which presumably activate the same CA3 neurons surrounding the electrode. The stimulus intensity for reliably pacing SWRs is weaker than that required for inducing detectable evoked field potentials in CA1. Moreover, repetitive ~1 Hz stimuli with low intensity can reliably evoke thousands of SWRs without detectable LTD or "habituation." Our results suggest that weak stimuli may facilitate the spontaneous emergence of SWRs without significantly altering their characteristics. Pacing SWRs with weak electric stimuli could potentially be useful for restoring their abundance in the damaged hippocampus.
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Affiliation(s)
- Huiyi Jiang
- Department of Pediatrics, The First Hospital of Jilin University, Chang Chun, China
- Department of Neuroscience, Georgetown University Medical Center, Georgetown University, Washington, DC, United States
| | - Shicheng Liu
- Department of Pediatrics, The First Hospital of Jilin University, Chang Chun, China
- Department of Neuroscience, Georgetown University Medical Center, Georgetown University, Washington, DC, United States
| | - Xinling Geng
- School of Biomedical Engineering, Capital Medical University, Beijing, China
| | - Adam Caccavano
- Department of Pharmacology, Georgetown University Medical Center, Georgetown University, Washington, DC, United States
| | - Katherine Conant
- Department of Neuroscience, Georgetown University Medical Center, Georgetown University, Washington, DC, United States
| | - Stefano Vicini
- Department of Pharmacology, Georgetown University Medical Center, Georgetown University, Washington, DC, United States
| | - Jianyoung Wu
- Department of Neuroscience, Georgetown University Medical Center, Georgetown University, Washington, DC, United States
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17
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Abstract
One of the most striking features of the hippocampal network is its ability to self-generate neuronal sequences representing temporally compressed, spatially coherent paths. These brief events, often termed "replay" in the scientific literature, are largely confined to non-exploratory states such as sleep or quiet rest. Early studies examining the content of replay noted a strong correlation between the encoded spatial information and the animal's prior behavior; thus, replay was initially hypothesized to play a role in memory formation and/or systems-level consolidation via "off-line" reactivation of previous experiences. However, recent findings indicate that replay may also serve as a memory retrieval mechanism to guide future behavior or may be an incidental reflection of pre-existing network assemblies. Here, I will review what is known regarding the content of replay events and their correlation with past and future actions, and I will discuss how this knowledge might inform or constrain models which seek to explain the circuit-level mechanisms underlying these events and their role in mnemonic processes.
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Affiliation(s)
- Brad E Pfeiffer
- Department of Neuroscience, UT Southwestern Medical Center, Dallas, Texas, 75390
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18
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Kouvaros S, Papatheodoropoulos C. Prominent differences in sharp waves, ripples and complex spike bursts between the dorsal and the ventral rat hippocampus. Neuroscience 2017; 352:131-43. [DOI: 10.1016/j.neuroscience.2017.03.050] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 03/27/2017] [Accepted: 03/27/2017] [Indexed: 12/17/2022]
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19
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Li Y, Chen X, Dzakpasu R, Conant K. Dopamine-dependent effects on basal and glutamate stimulated network dynamics in cultured hippocampal neurons. J Neurochem 2017; 140:550-560. [PMID: 27925199 DOI: 10.1111/jnc.13915] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 11/23/2016] [Accepted: 11/28/2016] [Indexed: 01/15/2023]
Abstract
Oscillatory activity occurs in cortical and hippocampal networks with specific frequency ranges thought to be critical to working memory, attention, differentiation of neuronal precursors, and memory trace replay. Synchronized activity within relatively large neuronal populations is influenced by firing and bursting frequency within individual cells, and the latter is modulated by changes in intrinsic membrane excitability and synaptic transmission. Published work suggests that dopamine, a potent modulator of learning and memory, acts on dopamine receptor 1-like dopamine receptors to influence the phosphorylation and trafficking of glutamate receptor subunits, along with long-term potentiation of excitatory synaptic transmission in striatum and prefrontal cortex. Prior studies also suggest that dopamine can influence voltage gated ion channel function and membrane excitability in these regions. Fewer studies have examined dopamine's effect on related endpoints in hippocampus, or potential consequences in terms of network burst dynamics. In this study, we record action potential activity using a microelectrode array system to examine the ability of dopamine to modulate baseline and glutamate-stimulated bursting activity in an in vitro network of cultured murine hippocampal neurons. We show that dopamine stimulates a dopamine type-1 receptor-dependent increase in number of overall bursts within minutes of its application. Notably, however, at the concentration used herein, dopamine did not increase the overall synchrony of bursts between electrodes. Although the number of bursts normalizes by 40 min, bursting in response to a subsequent glutamate challenge is enhanced by dopamine pretreatment. Dopamine-dependent potentiation of glutamate-stimulated bursting was not observed when the two modulators were administered concurrently. In parallel, pretreatment of murine hippocampal cultures with dopamine stimulated lasting increases in the phosphorylation of the glutamate receptor subunit GluA1 at serine 845. This effect is consistent with the possibility that enhanced membrane insertion of GluAs may contribute to a more slowly evolving dopamine-dependent potentiation of glutamate-stimulated bursting. Together, these results are consistent with the possibility that dopamine can influence hippocampal bursting by at least two temporally distinct mechanisms, contributing to an emerging appreciation of dopamine-dependent effects on network activity in the hippocampus.
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Affiliation(s)
- Yan Li
- Department of Neuroscience, Georgetown University School of Medicine, Washington, District of Columbia, USA
| | - Xin Chen
- Department of Physics, Georgetown University, Washington, District of Columbia, USA
| | - Rhonda Dzakpasu
- Department of Physics, Georgetown University, Washington, District of Columbia, USA.,Department of Pharmacology, Georgetown University School of Medicine, Washington, District of Columbia, USA.,Interdisciplinary Program in Neuroscience, Georgetown University School of Medicine, Washington, District of Columbia, USA
| | - Katherine Conant
- Department of Neuroscience, Georgetown University School of Medicine, Washington, District of Columbia, USA.,Interdisciplinary Program in Neuroscience, Georgetown University School of Medicine, Washington, District of Columbia, USA
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20
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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21
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Abstract
Sharp wave ripples (SPW‐Rs) represent the most synchronous population pattern in the mammalian brain. Their excitatory output affects a wide area of the cortex and several subcortical nuclei. SPW‐Rs occur during “off‐line” states of the brain, associated with consummatory behaviors and non‐REM sleep, and are influenced by numerous neurotransmitters and neuromodulators. They arise from the excitatory recurrent system of the CA3 region and the SPW‐induced excitation brings about a fast network oscillation (ripple) in CA1. The spike content of SPW‐Rs is temporally and spatially coordinated by a consortium of interneurons to replay fragments of waking neuronal sequences in a compressed format. SPW‐Rs assist in transferring this compressed hippocampal representation to distributed circuits to support memory consolidation; selective disruption of SPW‐Rs interferes with memory. Recently acquired and pre‐existing information are combined during SPW‐R replay to influence decisions, plan actions and, potentially, allow for creative thoughts. In addition to the widely studied contribution to memory, SPW‐Rs may also affect endocrine function via activation of hypothalamic circuits. Alteration of the physiological mechanisms supporting SPW‐Rs leads to their pathological conversion, “p‐ripples,” which are a marker of epileptogenic tissue and can be observed in rodent models of schizophrenia and Alzheimer's Disease. Mechanisms for SPW‐R genesis and function are discussed in this review. © 2015 The Authors Hippocampus Published by Wiley Periodicals, Inc.
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Affiliation(s)
- György Buzsáki
- The Neuroscience Institute, School of Medicine and Center for Neural Science, New York University, New York, New York
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22
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Nakayama R, Sasaki T, Tanaka KF, Ikegaya Y. Subcellular calcium dynamics during juvenile development in mouse hippocampal astrocytes. Eur J Neurosci 2016; 43:923-32. [PMID: 27041234 DOI: 10.1111/ejn.13188] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Revised: 12/26/2015] [Accepted: 01/26/2016] [Indexed: 12/15/2022]
Abstract
Astrocytes generate calcium signals throughout their fine processes, which are assumed to locally regulate neighbouring neurotransmission and blood flow. The intercellular morphological relationships mature during juvenile periods when astrocytes elongate highly ramified processes. In this study, we examined developmental changes in calcium activity patterns of single hippocampal astrocytes using a transgenic mouse line in which astrocytes selectively express a genetically encoded calcium indicator, Yellow Cameleon-Nano50. Compared with postnatal day 7, astrocytes at postnatal day 30 showed larger subcellular calcium events and a greater proportion of somatic events. At both ages, the calcium activity was abolished by removal of extracellular calcium ions. Calcium events in late juvenile astrocytes were not affected by spontaneously occurring sharp waves that trigger synchronized neuronal spikes, implying the independence of astrocyte calcium signals from neuronal synchronization. These results demonstrate that astrocytes undergo dynamic changes in their activity patterns during juvenile development.
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Affiliation(s)
- Ryota Nakayama
- Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan
| | - Takuya Sasaki
- Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan
| | - Kenji F Tanaka
- Department of Neuropsychiatry, School of Medicine, Keio University, Tokyo, Japan
| | - Yuji Ikegaya
- Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan.,Center for Information and Neural Networks, Osaka, Japan
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23
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Abstract
Salient events activate the midbrain dopaminergic system and have important impacts on various aspects of mnemonic function, including the stability of hippocampus-dependent memories. Dopamine is also central to modulation of neocortical memory processing, particularly during prefrontal cortex-dependent working memory. Here, we review the current state of the circuitry and physiology underlying dopamine's actions, suggesting that--alongside local effects within hippocampus and prefrontal cortex--dopamine released from the midbrain ventral tegmental area is well positioned to dynamically tune interactions between limbic-cortical circuits through modulation of rhythmic network activity.
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Affiliation(s)
- Emilie Werlen
- School of Physiology and Pharmacology, University of Bristol, University Walk, Bristol, UK.
| | - Matthew W Jones
- School of Physiology and Pharmacology, University of Bristol, University Walk, Bristol, UK
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