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Li Y, Hou S, Li F, Long S, Yang Y, Li Y, Zhao L, Yu Y. Preoperative recovery sleep ameliorates postoperative cognitive dysfunction aggravated by sleep fragmentation in aged mice by enhancing EEG delta-wave activity and LFP theta oscillation in hippocampal CA1. Brain Res Bull 2024; 211:110945. [PMID: 38608544 DOI: 10.1016/j.brainresbull.2024.110945] [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: 12/07/2023] [Revised: 03/10/2024] [Accepted: 04/08/2024] [Indexed: 04/14/2024]
Abstract
Sleep fragmentation (SF) is a common sleep problem experienced during the perioperative period by older adults, and is associated with postoperative cognitive dysfunction (POCD). Increasing evidence indicates that delta-wave activity during non-rapid eye movement (NREM) sleep is involved in sleep-dependent memory consolidation and that hippocampal theta oscillations are related to spatial exploratory memory. Recovery sleep (RS), a self-regulated state of sleep homeostasis, enhances delta-wave power and memory performance in sleep-deprived older mice. However, it remains unclear whether RS therapy has a positive effect on cognitive changes following SF in older mouse models. Therefore, this study aimed to explore whether preoperative RS can alleviate cognitive deficits in aged mice with SF. A model of preoperative 24-h SF combined with exploratory laparotomy-induced POCD was established in 18-month-old mice. Aged mice were treated with preoperative 6-h RS following SF and postoperative 6-h RS following surgery, respectively. The changes in hippocampus-dependent cognitive function were investigated using behavioral tests, electroencephalography (EEG), local field potential (LFP), magnetic resonance imaging, and neuromorphology. Mice that underwent 24-h SF combined with surgery exhibited severe spatial memory impairment; impaired cognitive performance could be alleviated by preoperative RS treatment. In addition, preoperative RS increased NREM sleep; enhanced EEG delta-wave activity and LFP theta oscillation in the hippocampal CA1; and improved hippocampal perfusion, microstructural integrity, and neuronal damage. Taken together, these results provide evidence that preoperative RS may ameliorate the severity of POCD aggravated by SF by enhancing delta slow-wave activity and hippocampal theta oscillation, and by ameliorating the reduction in regional cerebral blood flow and white matter microstructure integrity in the hippocampus.
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Affiliation(s)
- Yun Li
- Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin 300052, China; Tianjin Research Institute of Anesthesiology, Tianjin 300052, China
| | - Shaowei Hou
- School of Biomedical Engineering and Technology, Tianjin Medical University, Tianjin 300070, China
| | - Feixiang Li
- Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin 300052, China; Tianjin Research Institute of Anesthesiology, Tianjin 300052, China
| | - Siwen Long
- Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin 300052, China; Tianjin Research Institute of Anesthesiology, Tianjin 300052, China
| | - Yue Yang
- Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin 300052, China; Tianjin Research Institute of Anesthesiology, Tianjin 300052, China
| | - Yize Li
- Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin 300052, China; Tianjin Research Institute of Anesthesiology, Tianjin 300052, China
| | - Lina Zhao
- Department of Critical Care Medicine, Tianjin Medical University General Hospital, Tianjin 300052, China.
| | - Yonghao Yu
- Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin 300052, China; Tianjin Research Institute of Anesthesiology, Tianjin 300052, China.
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2
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Carretero-Guillén A, Treviño M, Gómez-Climent MÁ, Dogbevia GK, Bertocchi I, Sprengel R, Larkum ME, Vlachos A, Gruart A, Delgado-García JM, Hasan MT. Dentate gyrus is needed for memory retrieval. Mol Psychiatry 2024:10.1038/s41380-024-02546-0. [PMID: 38609585 DOI: 10.1038/s41380-024-02546-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 03/03/2024] [Accepted: 03/26/2024] [Indexed: 04/14/2024]
Abstract
The hippocampus is crucial for acquiring and retrieving episodic and contextual memories. In previous studies, the inactivation of dentate gyrus (DG) neurons by chemogenetic- and optogenetic-mediated hyperpolarization led to opposing conclusions about DG's role in memory retrieval. One study used Designer Receptors Exclusively Activated by Designer Drugs (DREADD)-mediated clozapine N-oxide (CNO)-induced hyperpolarization and reported that the previously formed memory was erased, thus concluding that denate gyrus is needed for memory maintenance. The other study used optogenetic with halorhodopsin induced hyperpolarization and reported and dentate gyrus is needed for memory retrieval. We hypothesized that this apparent discrepancy could be due to the length of hyperpolarization in previous studies; minutes by optogenetics and several hours by DREADD/CNO. Since hyperpolarization interferes with anterograde and retrograde neuronal signaling, it is possible that the memory engram in the dentate gyrus and the entorhinal to hippocampus trisynaptic circuit was erased by long-term, but not with short-term hyperpolarization. We developed and applied an advanced chemogenetic technology to selectively silence synaptic output by blocking neurotransmitter release without hyperpolarizing DG neurons to explore this apparent discrepancy. We performed in vivo electrophysiology during trace eyeblink in a rabbit model of associative learning. Our work shows that the DG output is required for memory retrieval. Based on previous and recent findings, we propose that the actively functional anterograde and retrograde neuronal signaling is necessary to preserve synaptic memory engrams along the entorhinal cortex to the hippocampal trisynaptic circuit.
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Affiliation(s)
- Alejandro Carretero-Guillén
- Division of Neuroscience, University Pablo de Olavide, Seville, Spain
- Achucarro Basque Center for Neuroscience, Leioa, Spain
| | - Mario Treviño
- Max Planck Institute for Medical Research, Heidelberg, Germany
- Instituto de Neurociencias, Universidad de Guadalajara, Guadalajara, 44130, México
| | | | - Godwin K Dogbevia
- Max Planck Institute for Medical Research, Heidelberg, Germany
- Health Canada, Ottawa, ON, Canada
| | - Ilaria Bertocchi
- Max Planck Institute for Medical Research, Heidelberg, Germany
- Neuroscience Institute Cavalieri-Ottolenghi (NICO), University of Turin, Turin, Italy
| | - Rolf Sprengel
- Max Planck Institute for Medical Research, Heidelberg, Germany
| | | | | | - Agnès Gruart
- Division of Neuroscience, University Pablo de Olavide, Seville, Spain
| | | | - Mazahir T Hasan
- Achucarro Basque Center for Neuroscience, Leioa, Spain.
- Max Planck Institute for Medical Research, Heidelberg, Germany.
- NeuroCure, Charité - Universitätsmedizin, Berlin, Germany.
- Ikerbasque - Basque Foundation for Science, Bilbao, Spain.
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3
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Vingan I, Phatarpekar S, Tung VSK, Hernández AI, Evgrafov OV, Alarcon JM. Spatially Resolved Transcriptomic Signatures of Hippocampal Subregions and Arc-Expressing Ensembles in Active Place Avoidance Memory. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.12.30.573225. [PMID: 38260257 PMCID: PMC10802250 DOI: 10.1101/2023.12.30.573225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
The rodent hippocampus is a spatially organized neuronal network that supports the formation of spatial and episodic memories. We conducted bulk RNA sequencing and spatial transcriptomics experiments to measure gene expression changes in the dorsal hippocampus following the recall of active place avoidance (APA) memory. Through bulk RNA sequencing, we examined the gene expression changes following memory recall across the functionally distinct subregions of the dorsal hippocampus. We found that recall induced differentially expressed genes (DEGs) in the CA1 and CA3 hippocampal subregions were enriched with genes involved in synaptic transmission and synaptic plasticity, while DEGs in the dentate gyrus (DG) were enriched with genes involved in energy balance and ribosomal function. Through spatial transcriptomics, we examined gene expression changes following memory recall across an array of spots encompassing putative memory-associated neuronal ensembles marked by the expression of the IEGs Arc, Egr1, and c-Jun. Within samples from both trained and untrained mice, the subpopulations of spatial transcriptomic spots marked by these IEGs were transcriptomically and spatially distinct from one another. DEGs detected between Arc+ and Arc- spots exclusively in the trained mouse were enriched in several memory-related gene ontology terms, including "regulation of synaptic plasticity" and "memory." Our results suggest that APA memory recall is supported by regionalized transcriptomic profiles separating the CA1 and CA3 from the DG, transcriptionally and spatially distinct IEG expressing spatial transcriptomic spots, and biological processes related to synaptic plasticity as a defining the difference between Arc+ and Arc- spatial transcriptomic spots.
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Affiliation(s)
- Isaac Vingan
- School of Graduates Studies, Program in Neural and Behavioral Sciences, State University of New York, Downstate Health Sciences University, Brooklyn, NY, USA
| | - Shwetha Phatarpekar
- Institute of Genomics in Health, State University of New York, Downstate Health Sciences University, Brooklyn, NY, USA
| | - Victoria Sook Keng Tung
- School of Graduates Studies, Program in Molecular and Cell Biology, State University of New York, Downstate Health Sciences University, Brooklyn, NY, USA
| | - A Iván Hernández
- School of Graduates Studies, Program in Neural and Behavioral Sciences, State University of New York, Downstate Health Sciences University, Brooklyn, NY, USA
- Department of Pathology, State University of New York, Downstate Health Sciences University, Brooklyn, NY, USA
- The Robert F. Furchgott Center for Neural & Behavioral Science, State University of New York, Downstate Health Sciences University, Brooklyn, NY, USA
| | - Oleg V Evgrafov
- Institute of Genomics in Health, State University of New York, Downstate Health Sciences University, Brooklyn, NY, USA
- School of Graduates Studies, Program in Molecular and Cell Biology, State University of New York, Downstate Health Sciences University, Brooklyn, NY, USA
- Department of Cell Biology, State University of New York, Downstate Health Sciences University, Brooklyn, NY, USA
- Department of Genetics, Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ, USA
| | - Juan Marcos Alarcon
- School of Graduates Studies, Program in Neural and Behavioral Sciences, State University of New York, Downstate Health Sciences University, Brooklyn, NY, USA
- Department of Pathology, State University of New York, Downstate Health Sciences University, Brooklyn, NY, USA
- The Robert F. Furchgott Center for Neural & Behavioral Science, State University of New York, Downstate Health Sciences University, Brooklyn, NY, USA
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4
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Hainmueller T, Cazala A, Huang LW, Bartos M. Subfield-specific interneuron circuits govern the hippocampal response to novelty in male mice. Nat Commun 2024; 15:714. [PMID: 38267409 PMCID: PMC10808551 DOI: 10.1038/s41467-024-44882-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Accepted: 01/04/2024] [Indexed: 01/26/2024] Open
Abstract
The hippocampus is the brain's center for episodic memories. Its subregions, the dentate gyrus and CA1-3, are differentially involved in memory encoding and recall. Hippocampal principal cells represent episodic features like movement, space, and context, but less is known about GABAergic interneurons. Here, we performed two-photon calcium imaging of parvalbumin- and somatostatin-expressing interneurons in the dentate gyrus and CA1-3 of male mice exploring virtual environments. Parvalbumin-interneurons increased activity with running-speed and reduced it in novel environments. Somatostatin-interneurons in CA1-3 behaved similar to parvalbumin-expressing cells, but their dentate gyrus counterparts increased activity during rest and in novel environments. Congruently, chemogenetic silencing of dentate parvalbumin-interneurons had prominent effects in familiar contexts, while silencing somatostatin-expressing cells increased similarity of granule cell representations between novel and familiar environments. Our data indicate unique roles for parvalbumin- and somatostatin-positive interneurons in the dentate gyrus that are distinct from those in CA1-3 and may support routing of novel information.
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Affiliation(s)
- Thomas Hainmueller
- Institute for Physiology I, University of Freiburg, Medical Faculty, 79104, Freiburg, Germany.
- NYU Neuroscience Institute, 435 East 30th Street, New York, NY, 10016, USA.
- Department of Psychiatry, New York University Langone Medical Center, New York, NY, 10016, USA.
| | - Aurore Cazala
- Institute for Physiology I, University of Freiburg, Medical Faculty, 79104, Freiburg, Germany
| | - Li-Wen Huang
- Institute for Physiology I, University of Freiburg, Medical Faculty, 79104, Freiburg, Germany
| | - Marlene Bartos
- Institute for Physiology I, University of Freiburg, Medical Faculty, 79104, Freiburg, Germany.
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5
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Zhvania M, Japaridze N, Tizabi Y, Lomidze N, Pochkhidze N, Rzayev F, Gasimov E. Differential effects of aging on hippocampal ultrastructure in male vs. female rats. Biogerontology 2023; 24:925-935. [PMID: 37515624 DOI: 10.1007/s10522-023-10052-z] [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: 04/28/2023] [Accepted: 07/09/2023] [Indexed: 07/31/2023]
Abstract
Age-related decline in physical and cognitive functions are facts of life that do not affect everyone to the same extent. We had reported earlier that such cognitive decline is both sex- and context-dependent. Moreover, age-associated ultrastructural changes were observed in the hippocampus of male rats. In this study, we sought to determine potential differences in ultrastructural changes between male and female rats at various stages of life. We performed quantitative electron microscopic evaluation of hippocampal CA1 region, an area intimately involved in cognitive behavior, in both male and female adolescent, adult and old Wistar rats. Specifically, we measured the number of docking synaptic vesicles in axo-dendritic synapses, the length of active zone as well as the total number of synaptic vesicles. Distinct age- and sex-dependent effects were observed in several parameters. Thus, adult female rats had the lowest synaptic active zone compared to both adolescent and old female rats. Moreover, the same parameter was significantly lower in adult and old female rats compared to their male counterparts. On the other hand, old male rats had significantly lower number of total synaptic vesicles compared to both adolescent and adult male rats as well as compared to their female counterparts. Taken together, it may be suggested that age- and sex-dependent ultrastructural changes in the hippocampus may underlie at least some of the differences in cognitive functions among these groups.
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Affiliation(s)
- Mzia Zhvania
- School of Natural Sciences and Medicine, Ilia State University, 3/5 K. Cholokashvili Avenue, 0162, Tbilisi, Georgia.
- Department of Brain Ultrastructure and Nanoarchitecture, Ivane Beritashvili Center of Experimental Biomedicine, Tbilisi, Georgia.
| | - Nadezhda Japaridze
- Department of Brain Ultrastructure and Nanoarchitecture, Ivane Beritashvili Center of Experimental Biomedicine, Tbilisi, Georgia
- New Vision University, Tbilisi, Georgia
| | - Yousef Tizabi
- Department of Pharmacology, Howard University College of Medicine, Washington, DC, USA
| | - Nino Lomidze
- School of Natural Sciences and Medicine, Ilia State University, 3/5 K. Cholokashvili Avenue, 0162, Tbilisi, Georgia
- Department of Brain Ultrastructure and Nanoarchitecture, Ivane Beritashvili Center of Experimental Biomedicine, Tbilisi, Georgia
| | - Nino Pochkhidze
- School of Natural Sciences and Medicine, Ilia State University, 3/5 K. Cholokashvili Avenue, 0162, Tbilisi, Georgia
- Department of Brain Ultrastructure and Nanoarchitecture, Ivane Beritashvili Center of Experimental Biomedicine, Tbilisi, Georgia
| | - Fuad Rzayev
- Department of Histology, Embryology and Cytology, Azerbaijan Medical University, Baku, Azerbaijan
| | - Eldar Gasimov
- Department of Histology, Embryology and Cytology, Azerbaijan Medical University, Baku, Azerbaijan
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6
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Atucha E, Ku SP, Lippert MT, Sauvage MM. Recalling gist memory depends on CA1 hippocampal neurons for lifetime retention and CA3 neurons for memory precision. Cell Rep 2023; 42:113317. [PMID: 37897725 DOI: 10.1016/j.celrep.2023.113317] [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: 01/19/2023] [Revised: 07/05/2023] [Accepted: 10/05/2023] [Indexed: 10/30/2023] Open
Abstract
Why some of us remember events more clearly than others and why memory loses precision over time is a major focus in memory research. Here, we show that the recruitment of specific neuroanatomical pathways within the medial temporal lobe (MTL) of the brain defines the precision of the memory recalled over the lifespan. Using optogenetics, neuronal activity mapping, and studying recent to very remote memories, we report that the hippocampal subfield CA1 is necessary for retrieving the gist of events and receives maximal support from MTL cortical areas (MEC, LEC, PER, and POR) for recalling the most remote memories. In contrast, reduction of CA3's activity alone coincides with the loss of memory precision over time. We propose that a shift between specific MTL subnetworks over time might be a fundamental mechanism of memory consolidation.
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Affiliation(s)
- Erika Atucha
- Functional Architecture of Memory Department, Leibniz Institute for Neurobiology, Magdeburg, Germany.
| | - Shih-Pi Ku
- Functional Architecture of Memory Department, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Michael T Lippert
- Systems Physiology of Learning Department, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Magdalena M Sauvage
- Functional Architecture of Memory Department, Leibniz Institute for Neurobiology, Magdeburg, Germany; Otto von Guericke University, Medical Faculty, Functional Neuroplasticity Department, Magdeburg, Germany; Otto von Guericke University, Center for Behavioral Brain Sciences, Magdeburg, Germany.
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7
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Griego E, Galván EJ. BDNF and Lactate as Modulators of Hippocampal CA3 Network Physiology. Cell Mol Neurobiol 2023; 43:4007-4022. [PMID: 37874456 DOI: 10.1007/s10571-023-01425-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2023] [Accepted: 10/14/2023] [Indexed: 10/25/2023]
Abstract
Growing evidence supports the notion that brain-derived neurotrophic factor (BDNF) and lactate are potent modulators of mammalian brain function. The modulatory actions of those biomolecules influence a wide range of neuronal responses, from the shaping of neuronal excitability to the induction and expression of structural and synaptic plasticity. The biological actions of BDNF and lactate are mediated by their cognate receptors and specific transporters located in the neuronal membrane. Canonical functions of BDNF occur via the tropomyosin-related kinase B receptor (TrkB), whereas lactate acts via monocarboxylate transporters or the hydroxycarboxylic acid receptor 1 (HCAR1). Both receptors are highly expressed in the central nervous system, and some of their physiological actions are particularly well characterized in the hippocampus, a brain structure involved in the neurophysiology of learning and memory. The multifarious neuronal circuitry between the axons of the dentate gyrus granule cells, mossy fibers (MF), and pyramidal neurons of area CA3 is of great interest given its role in specific mnemonic processes and involvement in a growing number of brain disorders. Whereas the modulation exerted by BDNF via TrkB has been extensively studied, the influence of lactate via HCAR1 on the properties of the MF-CA3 circuit is an emerging field. In this review, we discuss the role of both systems in the modulation of brain physiology, with emphasis on the hippocampal CA3 network. We complement this review with original data that suggest cross-modulation is exerted by these two independent neuromodulatory systems.
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Affiliation(s)
- Ernesto Griego
- Departamento de Farmacobiología, Cinvestav Sur, Mexico City, Mexico.
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York, USA.
- Departamento de Farmacobiología, Centro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional, Calzada de los Tenorios No. 235, Col. Granjas Coapa, C.P. 14330, Mexico City, Mexico.
| | - Emilio J Galván
- Departamento de Farmacobiología, Cinvestav Sur, Mexico City, Mexico
- Centro de Investigaciones sobre el Envejecimiento, Mexico City, Mexico
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Zernov N, Popugaeva E. Role of Neuronal TRPC6 Channels in Synapse Development, Memory Formation and Animal Behavior. Int J Mol Sci 2023; 24:15415. [PMID: 37895105 PMCID: PMC10607207 DOI: 10.3390/ijms242015415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 10/11/2023] [Accepted: 10/16/2023] [Indexed: 10/29/2023] Open
Abstract
The transient receptor potential cation channel, subfamily C, member 6 (TRPC6), has been believed to adjust the formation of an excitatory synapse. The positive regulation of TRPC6 engenders synapse enlargement and improved learning and memory in animal models. TRPC6 is involved in different synaptoprotective signaling pathways, including antagonism of N-methyl-D-aspartate receptor (NMDAR), activation of brain-derived neurotrophic factor (BDNF) and postsynaptic store-operated calcium entry. Positive regulation of TRPC6 channels has been repeatedly shown to be good for memory formation and storage. TRPC6 is mainly expressed in the hippocampus, particularly in the dentate granule cells, cornu Ammonis 3 (CA3) pyramidal cells and gamma-aminobutyric acid (GABA)ergic interneurons. It has been observed that TRPC6 agonists have a great influence on animal behavior including memory formation and storage The purpose of this review is to collect the available information on the role of TRPC6 in memory formation in various parts of the brain to understand how TRPC6-specific pharmaceutical agents will affect memory in distinct parts of the central nervous system (CNS).
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Affiliation(s)
| | - Elena Popugaeva
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, 195251 St. Petersburg, Russia
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9
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Cheng Y, Zhai Y, Yuan Y, Li H, Zhao W, Fan Z, Zhou L, Gao X, Zhan Y, Sun H. Xenon inhalation attenuates neuronal injury and prevents epilepsy in febrile seizure Sprague-Dawley pups. Front Cell Neurosci 2023; 17:1155303. [PMID: 37645594 PMCID: PMC10461106 DOI: 10.3389/fncel.2023.1155303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 07/27/2023] [Indexed: 08/31/2023] Open
Abstract
Background Febrile seizures (FS) usually occur in childhood and may cause irreversible neuronal damage, cognitive functional defects, and an increase in the risk of epilepsy later in life. Anti-epileptic drugs (AEDs), currently used to treat FS in children, can relieve seizures. However, their effects in preventing the risk of developing epilepsy in later life are unsatisfactory. Moreover, AEDs may damage child brain development. Here, we evaluated the efficiency of xenon in treating prolonged FS (PFS) and preventing epilepsy in Sprague-Dawley pups. Methods Prolonged FS was induced by hyperthermic treatment. After 90 min of PFS, the pups in the xenon treatment group were immediately treated with 70% xenon/21% oxygen/9% nitrogen for 60 min. The levels of glutamate, mitochondrial oxidative stress, mitophagy, and neuronal injury, seizures, learning, and memory functions were measured at specific time points. Results Neonatal period PFS led to spontaneous seizure, learning and memory dysfunction, accompanied by increased levels of glutamate, mitochondrial oxidative stress, mitophagy, and neuronal injury. Xenon treatment alleviated the changes caused by PFS and reduced the risk of PFS developing into epilepsy later. Conclusion Our results suggest that xenon inhalation could be a potential therapeutic strategy to attenuate neuronal injury and prevent epilepsy in patients with FS.
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Affiliation(s)
- Yao Cheng
- School of Pharmaceutical Sciences, Binzhou Medical University, Yantai, China
| | - Yujie Zhai
- School of Pharmaceutical Sciences, Binzhou Medical University, Yantai, China
| | - Yi Yuan
- School of Pharmaceutical Sciences, Binzhou Medical University, Yantai, China
| | - Hao Li
- School of Medical Imaging, Binzhou Medical University, Yantai, China
| | - Wenke Zhao
- School of Pharmaceutical Sciences, Binzhou Medical University, Yantai, China
| | - Zhenhai Fan
- School of Pharmaceutical Sciences, Binzhou Medical University, Yantai, China
| | - Ling Zhou
- School of Pharmaceutical Sciences, Binzhou Medical University, Yantai, China
| | - Xue Gao
- School of Pharmaceutical Sciences, Binzhou Medical University, Yantai, China
| | - Yan Zhan
- Department of Neurology, Yantai Affiliated Hospital of Binzhou Medical University, Yantai, China
| | - Hongliu Sun
- School of Pharmaceutical Sciences, Binzhou Medical University, Yantai, China
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10
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Rahsepar B, Norman JF, Noueihed J, Lahner B, Quick MH, Ghaemi K, Pandya A, Fernandez FR, Ramirez S, White JA. Theta-phase-specific modulation of dentate gyrus memory neurons. eLife 2023; 12:e82697. [PMID: 37401757 PMCID: PMC10361715 DOI: 10.7554/elife.82697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Accepted: 07/03/2023] [Indexed: 07/05/2023] Open
Abstract
The theta rhythm, a quasi-periodic 4-10 Hz oscillation, is observed during memory processing in the hippocampus, with different phases of theta hypothesized to separate independent streams of information related to the encoding and recall of memories. At the cellular level, the discovery of hippocampal memory cells (engram neurons), as well as the modulation of memory recall through optogenetic activation of these cells, has provided evidence that certain memories are stored, in part, in a sparse ensemble of neurons in the hippocampus. In previous research, however, engram reactivation has been carried out using open-loop stimulation at fixed frequencies; the relationship between engram neuron reactivation and ongoing network oscillations has not been taken into consideration. To address this concern, we implemented a closed-loop reactivation of engram neurons that enabled phase-specific stimulation relative to theta oscillations in the local field potential in CA1. Using this real-time approach, we tested the impact of activating dentate gyrus engram neurons during the peak (encoding phase) and trough (recall phase) of theta oscillations. Consistent with previously hypothesized functions of theta oscillations in memory function, we show that stimulating dentate gyrus engram neurons at the trough of theta is more effective in eliciting behavioral recall than either fixed-frequency stimulation or stimulation at the peak of theta. Moreover, phase-specific trough stimulation is accompanied by an increase in the coupling between gamma and theta oscillations in CA1 hippocampus. Our results provide a causal link between phase-specific activation of engram cells and the behavioral expression of memory.
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Affiliation(s)
- Bahar Rahsepar
- Department of Biomedical Engineering, Boston UniversityBostonUnited States
- Center for Systems Neuroscience, Neurophotonics Center, Boston UniversityBostonUnited States
- Department of Biology, Boston UniversityBostonUnited States
| | - Jacob F Norman
- Department of Biomedical Engineering, Boston UniversityBostonUnited States
- Center for Systems Neuroscience, Neurophotonics Center, Boston UniversityBostonUnited States
| | - Jad Noueihed
- Department of Biomedical Engineering, Boston UniversityBostonUnited States
- Center for Systems Neuroscience, Neurophotonics Center, Boston UniversityBostonUnited States
| | - Benjamin Lahner
- Department of Biomedical Engineering, Boston UniversityBostonUnited States
| | - Melanie H Quick
- Department of Biomedical Engineering, Boston UniversityBostonUnited States
| | - Kevin Ghaemi
- Department of Biomedical Engineering, Boston UniversityBostonUnited States
| | - Aashna Pandya
- Department of Biology, Boston UniversityBostonUnited States
| | - Fernando R Fernandez
- Department of Biomedical Engineering, Boston UniversityBostonUnited States
- Center for Systems Neuroscience, Neurophotonics Center, Boston UniversityBostonUnited States
| | - Steve Ramirez
- Department of Biomedical Engineering, Boston UniversityBostonUnited States
- Center for Systems Neuroscience, Neurophotonics Center, Boston UniversityBostonUnited States
- Department of Psychological and Brain Sciences, Boston UniversityBostonUnited States
| | - John A White
- Department of Biomedical Engineering, Boston UniversityBostonUnited States
- Center for Systems Neuroscience, Neurophotonics Center, Boston UniversityBostonUnited States
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11
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Fung CCA, Fukai T. Competition on presynaptic resources enhances the discrimination of interfering memories. PNAS NEXUS 2023; 2:pgad161. [PMID: 37275260 PMCID: PMC10235910 DOI: 10.1093/pnasnexus/pgad161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 04/27/2023] [Accepted: 05/09/2023] [Indexed: 06/07/2023]
Abstract
Evidence suggests that hippocampal adult neurogenesis is critical for discriminating considerably interfering memories. During adult neurogenesis, synaptic competition modifies the weights of synaptic connections nonlocally across neurons, thus providing a different form of unsupervised learning from Hebb's local plasticity rule. However, how synaptic competition achieves separating similar memories largely remains unknown. Here, we aim to link synaptic competition with such pattern separation. In synaptic competition, adult-born neurons are integrated into the existing neuronal pool by competing with mature neurons for synaptic connections from the entorhinal cortex. We show that synaptic competition and neuronal maturation play distinct roles in separating interfering memory patterns. Furthermore, we demonstrate that a feedforward neural network trained by a competition-based learning rule can outperform a multilayer perceptron trained by the backpropagation algorithm when only a small number of samples are available. Our results unveil the functional implications and potential applications of synaptic competition in neural computation.
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Affiliation(s)
| | - Tomoki Fukai
- To whom correspondence should be addressed: (C.C.A. Fung); (T. Fukai)
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12
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Research progress on oxidative stress regulating different types of neuronal death caused by epileptic seizures. Neurol Sci 2022; 43:6279-6298. [DOI: 10.1007/s10072-022-06302-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Accepted: 07/24/2022] [Indexed: 12/09/2022]
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13
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Blackstad JS, Osen KK, Leergaard TB. The fibro- and cyto-architecture demarcating the border between the dentate gyrus and CA3 in sheep (Ovis aries) and domestic pig (Sus scrofa domesticus). Hippocampus 2022; 32:639-659. [PMID: 35913094 PMCID: PMC9546232 DOI: 10.1002/hipo.23457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Revised: 05/28/2022] [Accepted: 07/07/2022] [Indexed: 11/05/2022]
Abstract
The hippocampal formation is essential for spatial navigation and episodic memory. The anatomical structure is largely similar across mammalian species, apart from the deep polymorphic layer of the dentate gyrus and the adjacent part of cornu ammonis 3 (CA3) which feature substantial variations. In rodents, the polymorphic layer has a triangular cross‐section abutting on the end of the CA3 pyramidal layer, while in primates it is long and band‐shaped capping the expanded CA3 end, which here lacks a distinct pyramidal layer. This structural variation has resulted in a confusing nomenclature and unclear anatomical criteria for the definition of the dentate‐ammonic border. Seeking to clarify the border, we present here a light microscopic investigation based on Golgi‐impregnated and Timm–thionin‐stained sections of the Artiodactyla sheep and domestic pig, in which the dentate gyrus and CA3 end have some topographical features in common with primates. In short, the band‐shaped polymorphic layer coincides with the Timm‐positive mossy fiber collateral plexus and the Timm‐negative subgranular zone. While the soma and excrescence‐covered proximal dendrites of the mossy cells are localized within the plexus, the peripheral mossy cell dendrites extend outside the plexus, both into the granular and molecular layers, and the CA3. The main mossy fibers leave the collateral plexus in a scattered formation to converge gradually through the CA3 end in between the dispersed pyramidal cells, which are of three subtypes, as in monkey, with the classical apical subtype dominating near the hidden blade, the nonapical subtype near the exposed blade, and the dentate subtype being the only pyramidal cells that extend dendrites into the dentate gyrus. In agreement with our previous study in mink, the findings show that the border between the dentate gyrus and the CA3 end can be more accurately localized by the mossy fiber system than by cyto‐architecture alone.
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Affiliation(s)
- Jan Sigurd Blackstad
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.,Kavli Institute for Systems Neuroscience and Center for Biology of Memory, Norwegian University of Science and Technology, Trondheim, Norway
| | - Kirsten K Osen
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Trygve B Leergaard
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
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14
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Giordano KR, Law LM, Henderson J, Rowe RK, Lifshitz J. Time Course of Remote Neuropathology Following Diffuse Traumatic Brain Injury in the Male Rat. Exp Neurobiol 2022; 31:105-115. [PMID: 35673999 PMCID: PMC9194637 DOI: 10.5607/en21027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 12/15/2021] [Accepted: 04/12/2022] [Indexed: 11/19/2022] Open
Abstract
Traumatic brain injury (TBI) can affect different regions throughout the brain. Regions near the site of impact are the most vulnerable to injury. However, damage to distal regions occurs. We investigated progressive neuropathology in the dorsal hippocampus (near the impact) and cerebellum (distal to the impact) after diffuse TBI. Adult male rats were subjected to midline fluid percussion injury or sham injury. Brain tissue was stained by the amino cupric silver stain. Neuropathology was quantified in sub-regions of the dorsal hippocampus at 1, 7, and 28 days post-injury (DPI) and coronal cerebellar sections at 1, 2, and 7 DPI. The highest observed neuropathology in the dentate gyrus occurred at 7 DPI which attenuated by 28 DPI, whereas the highest observed neuropathology was at 1 DPI in the CA3 region. There was no significant neuropathology in the CA1 region at any time point. Neuropathology was increased at 7 DPI in the cerebellum compared to shams and stripes of pathology were observed in the molecular layer perpendicular to the cerebellar cortical surface. Together these data show that diffuse TBI can result in neuropathology across the brain. By describing the time course of pathology in response to TBI, it is possible to build the temporal profile of disease progression.
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Affiliation(s)
- Katherine R Giordano
- BARROW Neurological Institute at Phoenix Children's Hospital, Phoenix, AZ 85013, USA.,Department of Child Health, University of Arizona College of Medicine - Phoenix, Phoenix, AZ 85004, USA.,Phoenix Veterans Affairs Health Care System, Phoenix, AZ 85012, USA
| | - L Matthew Law
- BARROW Neurological Institute at Phoenix Children's Hospital, Phoenix, AZ 85013, USA.,Department of Child Health, University of Arizona College of Medicine - Phoenix, Phoenix, AZ 85004, USA.,Phoenix Veterans Affairs Health Care System, Phoenix, AZ 85012, USA
| | - Jordan Henderson
- BARROW Neurological Institute at Phoenix Children's Hospital, Phoenix, AZ 85013, USA.,Department of Child Health, University of Arizona College of Medicine - Phoenix, Phoenix, AZ 85004, USA
| | - Rachel K Rowe
- Department of Integrative Physiology, University of Colorado, Boulder, CO 80309, USA
| | - Jonathan Lifshitz
- BARROW Neurological Institute at Phoenix Children's Hospital, Phoenix, AZ 85013, USA.,Department of Child Health, University of Arizona College of Medicine - Phoenix, Phoenix, AZ 85004, USA.,Phoenix Veterans Affairs Health Care System, Phoenix, AZ 85012, USA
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15
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Bijata M, Bączyńska E, Müller FE, Bijata K, Masternak J, Krzystyniak A, Szewczyk B, Siwiec M, Antoniuk S, Roszkowska M, Figiel I, Magnowska M, Olszyński KH, Wardak AD, Hogendorf A, Ruszczycki B, Gorinski N, Labus J, Stępień T, Tarka S, Bojarski AJ, Tokarski K, Filipkowski RK, Ponimaskin E, Wlodarczyk J. Activation of the 5-HT7 receptor and MMP-9 signaling module in the hippocampal CA1 region is necessary for the development of depressive-like behavior. Cell Rep 2022; 38:110532. [PMID: 35294881 DOI: 10.1016/j.celrep.2022.110532] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 10/31/2021] [Accepted: 02/25/2022] [Indexed: 12/13/2022] Open
Abstract
Major depressive disorder is a complex disease resulting from aberrant synaptic plasticity that may be caused by abnormal serotonergic signaling. Using a combination of behavioral, biochemical, and imaging methods, we analyze 5-HT7R/MMP-9 signaling and dendritic spine plasticity in the hippocampus in mice treated with the selective 5-HT7R agonist (LP-211) and in a model of chronic unpredictable stress (CUS)-induced depressive-like behavior. We show that acute 5-HT7R activation induces depressive-like behavior in mice in an MMP-9-dependent manner and that post mortem brain samples from human individuals with depression reveal increased MMP-9 enzymatic activity in the hippocampus. Both pharmacological activation of 5-HT7R and modulation of its downstream effectors as a result of CUS lead to dendritic spine elongation and decreased spine density in this region. Overall, the 5-HT7R/MMP-9 pathway is specifically activated in the CA1 subregion of the hippocampus during chronic stress and is crucial for inducing depressive-like behavior.
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Affiliation(s)
- Monika Bijata
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Pasteura 3, 02-093 Warsaw, Poland; Cellular Neurophysiology, Center of Physiology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany.
| | - Ewa Bączyńska
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Pasteura 3, 02-093 Warsaw, Poland; The Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Franziska E Müller
- Cellular Neurophysiology, Center of Physiology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
| | - Krystian Bijata
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Pasteura 3, 02-093 Warsaw, Poland; Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland
| | - Julia Masternak
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Pasteura 3, 02-093 Warsaw, Poland
| | - Adam Krzystyniak
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Pasteura 3, 02-093 Warsaw, Poland
| | - Bernadeta Szewczyk
- Maj Institute of Pharmacology, Department of Neurobiology, Polish Academy of Sciences, Smętna 12, 31-343 Cracow, Poland
| | - Marcin Siwiec
- Maj Institute of Pharmacology, Department of Physiology, Polish Academy of Sciences, Smętna 12, 31-343 Cracow, Poland
| | - Svitlana Antoniuk
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Pasteura 3, 02-093 Warsaw, Poland; Cellular Neurophysiology, Center of Physiology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
| | - Matylda Roszkowska
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Pasteura 3, 02-093 Warsaw, Poland
| | - Izabela Figiel
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Pasteura 3, 02-093 Warsaw, Poland
| | - Marta Magnowska
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Pasteura 3, 02-093 Warsaw, Poland
| | - Krzysztof H Olszyński
- Behavior and Metabolism Research Laboratory, Mossakowski Medical Research Institute, Polish Academy of Sciences, Pawinskiego 5, 02-106 Warsaw, Poland
| | - Agnieszka D Wardak
- Behavior and Metabolism Research Laboratory, Mossakowski Medical Research Institute, Polish Academy of Sciences, Pawinskiego 5, 02-106 Warsaw, Poland
| | - Adam Hogendorf
- Maj Institute of Pharmacology, Department of Medicinal Chemistry, Polish Academy of Sciences, Smętna 12, 31-343 Cracow, Poland
| | - Błażej Ruszczycki
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Pasteura 3, 02-093 Warsaw, Poland
| | - Nataliya Gorinski
- Cellular Neurophysiology, Center of Physiology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
| | - Josephine Labus
- Cellular Neurophysiology, Center of Physiology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
| | - Tomasz Stępień
- Department of Neuropathology, Institute of Psychiatry and Neurology, Jana III Sobieskiego 9, 02-957 Warsaw, Poland
| | - Sylwia Tarka
- Department of Forensic Medicine, Medical University of Warsaw, Oczki 1, 02-007 Warsaw, Poland
| | - Andrzej J Bojarski
- Maj Institute of Pharmacology, Department of Medicinal Chemistry, Polish Academy of Sciences, Smętna 12, 31-343 Cracow, Poland
| | - Krzysztof Tokarski
- Maj Institute of Pharmacology, Department of Physiology, Polish Academy of Sciences, Smętna 12, 31-343 Cracow, Poland
| | - Robert K Filipkowski
- Behavior and Metabolism Research Laboratory, Mossakowski Medical Research Institute, Polish Academy of Sciences, Pawinskiego 5, 02-106 Warsaw, Poland
| | - Evgeni Ponimaskin
- Cellular Neurophysiology, Center of Physiology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
| | - Jakub Wlodarczyk
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Pasteura 3, 02-093 Warsaw, Poland.
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16
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Viñas-Noguera M, Csatlósová K, Šimončičová E, Bögi E, Ujházy E, Dubovický M, Belovičová K. Sex- and age- dependent effect of pre-gestational chronic stress and mirtazapine treatment on neurobehavioral development of Wistar rat offspring. PLoS One 2022; 17:e0255546. [PMID: 35113878 PMCID: PMC8812964 DOI: 10.1371/journal.pone.0255546] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 01/07/2022] [Indexed: 11/18/2022] Open
Abstract
Hormonal fluctuations, such as the perinatal period, may increase susceptibility of women to depression, which in turn exert a negative impact on child's neurodevelopment, becoming a risk factor in development of neuropsychiatric disorders. Moreover, the use of antidepressants during this critical period presents a serious health concern for both the mother and the child, due to the consequences of treatment in terms of the reliability and safety for the proper neurodevelopment of the organism being not well known. Atypical antidepressants, such as mirtazapine, that targets both serotonergic and noradrenergic systems in the central nervous system (CNS), represent a novel focus of research due to its unique pharmacological profile. The aim of this work was to study the effects of maternal depression and/or perinatal antidepressant mirtazapine treatment on the neurobehavioral development of the offspring. Pre-gestationally chronically stressed or non-stressed Wistar rat dams were treated with either mirtazapine (10 mg/kg/day) or vehicle during pregnancy and lactation followed by analysis of offspring's behavior at juvenile and adolescent age. We found mirtazapine induced significant alterations of nursing behavior. In offspring, pregestational stress (PS) had an anxiogenic effect on adolescent males (p≤0.05) and increased their active behavior in forced swim test (p≤0.01). Interaction between pregestational stress and mirtazapine treatment variously induced anxiolytic changes of juvenile (p≤0.05) and adolescent (p≤0.05) females and impairment of spatial memory (p≤0.01) in adolescent females as well. Hippocampal density of synaptophysin, pre-synaptic protein marker, was decreased mainly by mirtazapine treatment. In conclusion, our results show mirtazapine induced significant alterations in maternal behavior and several sex- and age-dependent changes in neurobehavioral development of offspring caused by both prenatal mirtazapine treatment and/or chronic pregestational stress.
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Affiliation(s)
- Mireia Viñas-Noguera
- Centre of Experimental Medicine, Institute of Experimental Pharmacology and Toxicology, Slovak Academy of Sciences, Bratislava, Slovakia
- Faculty of Natural Sciences, Comenius University, Bratislava, Slovakia
| | - Kristína Csatlósová
- Centre of Experimental Medicine, Institute of Experimental Pharmacology and Toxicology, Slovak Academy of Sciences, Bratislava, Slovakia
- Jessenius Faculty of Medicine, Comenius University, Martin, Slovakia
| | - Eva Šimončičová
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
| | - Ezster Bögi
- Centre of Experimental Medicine, Institute of Experimental Pharmacology and Toxicology, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Eduard Ujházy
- Centre of Experimental Medicine, Institute of Experimental Pharmacology and Toxicology, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Michal Dubovický
- Centre of Experimental Medicine, Institute of Experimental Pharmacology and Toxicology, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Kristína Belovičová
- Centre of Experimental Medicine, Institute of Experimental Pharmacology and Toxicology, Slovak Academy of Sciences, Bratislava, Slovakia
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17
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Adult hippocampal neurogenesis shapes adaptation and improves stress response: a mechanistic and integrative perspective. Mol Psychiatry 2022; 27:403-421. [PMID: 33990771 PMCID: PMC8960391 DOI: 10.1038/s41380-021-01136-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 04/09/2021] [Accepted: 04/19/2021] [Indexed: 02/03/2023]
Abstract
Adult hippocampal neurogenesis (AHN) represents a remarkable form of neuroplasticity that has increasingly been linked to the stress response in recent years. However, the hippocampus does not itself support the expression of the different dimensions of the stress response. Moreover, the main hippocampal functions are essentially preserved under AHN depletion and adult-born immature neurons (abGNs) have no extrahippocampal projections, which questions the mechanisms by which abGNs influence functions supported by brain areas far from the hippocampus. Within this framework, we propose that through its computational influences AHN is pivotal in shaping adaption to environmental demands, underlying its role in stress response. The hippocampus with its high input convergence and output divergence represents a computational hub, ideally positioned in the brain (1) to detect cues and contexts linked to past, current and predicted stressful experiences, and (2) to supervise the expression of the stress response at the cognitive, affective, behavioral, and physiological levels. AHN appears to bias hippocampal computations toward enhanced conjunctive encoding and pattern separation, promoting contextual discrimination and cognitive flexibility, reducing proactive interference and generalization of stressful experiences to safe contexts. These effects result in gating downstream brain areas with more accurate and contextualized information, enabling the different dimensions of the stress response to be more appropriately set with specific contexts. Here, we first provide an integrative perspective of the functional involvement of AHN in the hippocampus and a phenomenological overview of the stress response. We then examine the mechanistic underpinning of the role of AHN in the stress response and describe its potential implications in the different dimensions accompanying this response.
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18
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Prati JM, Guilherme EM, de Russo TL, Gianlorenço ACL. Neuronal activation of cerebellum functional circuits in motor and non-motor functions in mice. Neurosci Lett 2021; 765:136271. [PMID: 34597707 DOI: 10.1016/j.neulet.2021.136271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 09/18/2021] [Accepted: 09/23/2021] [Indexed: 10/20/2022]
Abstract
The cerebellum is involved in the control of balance, movement and the acquisition of motor skills. Scientific and technological advances have shown that the cerebellum also participates in non-motor functions, such as emotional control, memory and language. However, which cerebellar areas and functional circuits are predominantly activated in these different functions is not known. The current study analyzed the neuronal activation of cerebellar areas and other brain structures (e.g., hippocampus, amygdala, prelimbic cortex and infralimbic cortex) after exposure to rotarod and inhibitory avoidance behavioral models to establish possible neuronal circuits for motor and non-motor functions. Naïve male Swiss albino mice weighing 25 to 35 g were used. The animals were subjected to three conditions for behavioral evaluation: inhibitory avoidance, which is a model used to infer emotional memory; rotarod, which assesses motor performance and motor learning; and housing box/control. The mice remained in their housing box in Condition 1. Mice in Condition 2 were exposed to the inhibitory avoidance box for 2 days, and mice in Condition 3 were exposed to the rotarod for 3 days. The animals were euthanized after the last exposure to the apparatus then perfused with paraformaldehyde. Brains were extracted and sectioned for immunofluorescence analysis of c-Fos protein in pre-established structures. Images of the brain structures were obtained, and neuronal activation was analyzed microscopically. One-way analysis of variance was used, followed by Tukey's post-hoc test. There was no significant difference in c-Fos expression in lobe VI of the cerebellum between the different conditions. Differences in c-Fos expression were observed in the basolateral amygdala, infralimbic cortex and prelimbic cortex, which are relevant to emotional processes, after exposure to the evaluation apparatuses. Pearson's r correlation coefficient test showed a positive correlation between the variables of structures related to emotional processes. We concluded that there was no significant difference in c-Fos expression in lobe VI of the cerebellum after exposure of the animals to the evaluation apparatus. However, there was a difference in c-Fos expression in other brain structures related to emotional processes after exposure of animals to the apparatus.
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Affiliation(s)
- José Mário Prati
- Laboratory of Neuroscience, Department of Physiotherapy, Federal University of São Carlos, Brazil.
| | - Evelyn Maria Guilherme
- Laboratory of Neuroscience, Department of Physiotherapy, Federal University of São Carlos, Brazil.
| | - Thiago Luiz de Russo
- Laboratory of Neurological Physiotherapy, Department of Physiotherapy, Federal University of São Carlos, Brazil.
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19
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James T, Kula B, Choi S, Khan SS, Bekar LK, Smith NA. Locus coeruleus in memory formation and Alzheimer's disease. Eur J Neurosci 2021; 54:6948-6959. [PMID: 33190318 PMCID: PMC8121900 DOI: 10.1111/ejn.15045] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Revised: 10/27/2020] [Accepted: 10/28/2020] [Indexed: 12/26/2022]
Abstract
Catecholamine neurons of the locus coeruleus (LC) in the dorsal pontine tegmentum innervate the entire neuroaxis, with signaling actions implicated in the regulation of attention, arousal, sleep-wake cycle, learning, memory, anxiety, pain, mood, and brain metabolism. The co-release of norepinephrine (NE) and dopamine (DA) from LC terminals in the hippocampus plays a role in all stages of hippocampal-memory processing. This catecholaminergic regulation modulates the encoding, consolidation, retrieval, and reversal of hippocampus-based memory. LC neurons in awake animals have two distinct firing modes: tonic firing (explorative) and phasic firing (exploitative). These two firing modes exert different modulatory effects on post-synaptic dendritic spines. In the hippocampus, the firing modes regulate long-term potentiation (LTP) and long-term depression, which differentially regulate the mRNA expression and transcription of plasticity-related proteins (PRPs). These proteins aid in structural alterations of dendritic spines, that is, structural long-term potentiation (sLTP), via expansion and structural long-term depression (sLTD) via contraction of post-synaptic dendritic spines. Given the LC's role in all phases of memory processing, the degeneration of 50% of the LC neuron population occurring in Alzheimer's disease (AD) is a clinically relevant aspect of disease pathology. The loss of catecholaminergic regulation contributes to dysfunction in memory processes along with impaired functions associated with attention and task completion. The multifaceted role of the LC in memory and general task performance and the close correlation of LC degeneration with neurodegenerative disease progression together implicate it as a target for new clinical assessment tools.
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Affiliation(s)
- Tony James
- George Washington University School of Medicine and Health SciencesWashingtonDCUSA
| | - Bartosz Kula
- Center for NeuroscienceChildren's National Research InstituteChildren's National HospitalWashingtonDCUSA
| | - Seowon Choi
- Center for NeuroscienceChildren's National Research InstituteChildren's National HospitalWashingtonDCUSA
- Thomas Jefferson High School for Science and TechnologyAlexandriaVAUSA
| | | | - Lane K. Bekar
- Department of Anatomy, Physiology and PharmacologyUniversity of SaskatchewanSaskatoonCanada
| | - Nathan A. Smith
- George Washington University School of Medicine and Health SciencesWashingtonDCUSA
- Center for NeuroscienceChildren's National Research InstituteChildren's National HospitalWashingtonDCUSA
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20
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Santos VR, Melo IS, Pacheco ALD, Castro OWD. Life and death in the hippocampus: What's bad? Epilepsy Behav 2021; 121:106595. [PMID: 31759972 DOI: 10.1016/j.yebeh.2019.106595] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 09/30/2019] [Accepted: 10/01/2019] [Indexed: 01/13/2023]
Abstract
The hippocampal formation is crucial for the generation and regulation of several brain functions, including memory and learning processes; however, it is vulnerable to neurological disorders, such as epilepsy. Temporal lobe epilepsy (TLE), the most common type of epilepsy, changes the hippocampal circuitry and excitability, under the contribution of both neuronal degeneration and abnormal neurogenesis. Classically, neurodegeneration affects sensitive areas of the hippocampus, such as dentate gyrus (DG) hilus, as well as specific fields of the Ammon's horn, CA3, and CA1. In addition, the proliferation, migration, and abnormal integration of newly generated hippocampal granular cells (GCs) into the brain characterize TLE neurogenesis. Robust studies over the years have intensely discussed the effects of death and life in the hippocampus, though there are still questions to be answered about their possible benefits and risks. Here, we review the impacts of death and life in the hippocampus, discussing its influence on TLE, providing new perspectives or insights for the implementation of new possible therapeutic targets. This article is part of the Special Issue "NEWroscience 2018".
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Affiliation(s)
- Victor Rodrigues Santos
- Department of Morphology, Institute of Biological Sciences, Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil.
| | - Igor Santana Melo
- Institute of Biological Sciences and Health, Federal University of Alagoas (UFAL), Maceio, Brazil
| | | | - Olagide Wagner de Castro
- Institute of Biological Sciences and Health, Federal University of Alagoas (UFAL), Maceio, Brazil.
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21
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Xie R, Wang Z, Liu T, Xiao R, Lv K, Wu C, Luo Y, Cai Y, Fan X. AAV Delivery of shRNA Against TRPC6 in Mouse Hippocampus Impairs Cognitive Function. Front Cell Dev Biol 2021; 9:688655. [PMID: 34327201 PMCID: PMC8313999 DOI: 10.3389/fcell.2021.688655] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 06/22/2021] [Indexed: 11/13/2022] Open
Abstract
Transient Receptor Potential Canonical 6 (TRPC6) has been suggested to be involved in synapse function and contribute to hippocampal-dependent cognitive processes. Gene silencing of TRPC6 was performed by injecting adeno-associated virus (AAV) expressing TRPC6-specific shRNA (shRNA-TRPC6) into the hippocampal dentate gyrus (DG). Spatial learning, working memory and social recognition memory were impaired in the shRNA-TRPC6 treated mice compared to control mice after 4 weeks. In addition, gene ontology (GO) analysis of RNA-sequencing revealed that viral intervention of TRPC6 expression in DG resulted in the enrichment of the process of synaptic transmission and cellular compartment of synaptic structure. KEGG analysis showed PI3K-Akt signaling pathway were significantly down-regulated. Furthermore, the shRNA-TRPC6 treatment reduced dendritic spines of DG granule neurons, in terms of spine loss, the thin and mushroom types predominated. Accompanying the spine loss, the levels of PSD95, pAkt and CREB in the hippocampus were decreased in the shRNA-TRPC6 treated animals. Taken together, our results suggest that knocking down TRPC6 in the DG have a disadvantageous effect on cognitive processes.
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Affiliation(s)
- Ruxin Xie
- Department of Military Cognitive Psychology, School of Psychology, Third Military Medical University (Army Medical University), Chongqing, China
| | - Zhongke Wang
- Department of Military Cognitive Psychology, School of Psychology, Third Military Medical University (Army Medical University), Chongqing, China
| | - Tianyao Liu
- Department of Military Cognitive Psychology, School of Psychology, Third Military Medical University (Army Medical University), Chongqing, China
| | - Rui Xiao
- Department of Military Cognitive Psychology, School of Psychology, Third Military Medical University (Army Medical University), Chongqing, China
| | - Keyi Lv
- Department of Military Cognitive Psychology, School of Psychology, Third Military Medical University (Army Medical University), Chongqing, China
| | - Chuan Wu
- Department of Military Cognitive Psychology, School of Psychology, Third Military Medical University (Army Medical University), Chongqing, China
| | - Yi Luo
- Department of Military Cognitive Psychology, School of Psychology, Third Military Medical University (Army Medical University), Chongqing, China
| | - Yun Cai
- Department of Military Cognitive Psychology, School of Psychology, Third Military Medical University (Army Medical University), Chongqing, China
| | - Xiaotang Fan
- Department of Military Cognitive Psychology, School of Psychology, Third Military Medical University (Army Medical University), Chongqing, China
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Shohayeb B, Cooper HM. Mosaic synapses in epilepsy. Science 2021; 372:235-236. [PMID: 33859020 DOI: 10.1126/science.abh3555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Belal Shohayeb
- Queensland Brain Institute, University of Queensland, Brisbane, Queensland, Australia.
| | - Helen M Cooper
- Queensland Brain Institute, University of Queensland, Brisbane, Queensland, Australia.
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Ruby NF. Suppression of Circadian Timing and Its Impact on the Hippocampus. Front Neurosci 2021; 15:642376. [PMID: 33897354 PMCID: PMC8060574 DOI: 10.3389/fnins.2021.642376] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 03/17/2021] [Indexed: 01/02/2023] Open
Abstract
In this article, I describe the development of the disruptive phase shift (DPS) protocol and its utility for studying how circadian dysfunction impacts memory processing in the hippocampus. The suprachiasmatic nucleus (SCN) of the Siberian hamster is a labile circadian pacemaker that is easily rendered arrhythmic (ARR) by a simple manipulation of ambient lighting. The DPS protocol uses room lighting to administer a phase-advancing signal followed by a phase-delaying signal within one circadian cycle to suppress clock gene rhythms in the SCN. The main advantage of this model for inducing arrhythmia is that the DPS protocol is non-invasive; circadian rhythms are eliminated while leaving the animals neurologically and genetically intact. In the area of learning and memory, DPS arrhythmia produces much different results than arrhythmia by surgical ablation of the SCN. As I show, SCN ablation has little to no effect on memory. By contrast, DPS hamsters have an intact, but arrhythmic, SCN which produces severe deficits in memory tasks that are accompanied by fragmentation of electroencephalographic theta oscillations, increased synaptic inhibition in hippocampal circuits, and diminished responsiveness to cholinergic signaling in the dentate gyrus of the hippocampus. The studies reviewed here show that DPS hamsters are a promising model for translational studies of adult onset circadian dysfunction in humans.
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Affiliation(s)
- Norman F. Ruby
- Biology Department, Stanford University, Stanford, CA, United States
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24
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Matsuda VDV, Tejada MB, Motta-Teixeira LC, Ikebara JM, Cardoso DS, Machado-Nils AV, Lee VY, Diccini I, Arruda BP, Martins PP, Dias NMM, Tessarotto RP, Raeisossadati R, Bruno M, Takase LF, Kihara AH, Nogueira MI, Xavier GF, Takada SH. Impact of neonatal anoxia and hypothermic treatment on development and memory of rats. Exp Neurol 2021; 340:113691. [PMID: 33713657 DOI: 10.1016/j.expneurol.2021.113691] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Revised: 02/18/2021] [Accepted: 03/07/2021] [Indexed: 01/02/2023]
Abstract
Therapeutic hypothermia (TH) is well established as a standard treatment for term and near-term infants. However, therapeutic effects of hypothermia following neonatal anoxia in very premature babies remains inconclusive. The present rodent model of preterm neonatal anoxia has been shown to alter developmental milestones and hippocampal neurogenesis, and to disrupt spatial learning and memory in adulthood. These effects seem to be reduced by post-insult hypothermia. Epigenetic-related mechanisms have been postulated as valuable tools for developing new therapies. Dentate gyrus neurogenesis is regulated by epigenetic factors. This study evaluated whether TH effects in a rodent model of preterm oxygen deprivation are based on epigenetic alterations. The effects of TH on both developmental features (somatic growth, maturation of physical characteristics and early neurological reflexes) and performance of behavioral tasks at adulthood (spatial reference and working memory, and fear conditioning) were investigated in association with the possible involvement of the epigenetic operator Enhancer of zeste homolog 2 (Ezh2), possibly related to long-lasting effects on hippocampal neurogenesis. Results showed that TH reduced both anoxia-induced hippocampal neurodegeneration and anoxia-induced impairments on risk assessment behavior, acquisition of spatial memory, and extinction of auditory and contextual fear conditioning. In contrast, TH did not prevent developmental alterations caused by neonatal anoxia and did not restore hippocampal neurogenesis or cause changes in EZH2 levels. In conclusion, despite the beneficial effects of TH in hippocampal neurodegeneration and in reversing disruption of performance of behavioral tasks following oxygen deprivation in prematurity, these effects seem not related to developmental alterations and hippocampal neurogenesis and, apparently, is not caused by Ezh2-mediated epigenetic alteration.
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Affiliation(s)
- Victor Daniel Vasquez Matsuda
- Neuroscience and Behaviour Laboratory, Department of Physiology, Institute of Biosciences, Universidade de São Paulo, São Paulo, SP, Brazil; Neuroscience Laboratory, Department of Anatomy, Institute of Biomedical Sciences, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Martin Bustelo Tejada
- Department of Pediatrics, Maastricht University Medical Center (MUMC), Maastricht, the Netherlands; Experimental Neuropathology Laboratory, Institute of Cellular Biology and Neuroscience "Prof. E. De Robertis" (IBCN), Faculty of Medicine, University of Buenos Aires, CONICET, Buenos Aires, Argentina; Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience (MHeNs), Maastricht University, Maastricht, the Netherlands; Biomedical Sciences Institute, Faculty of Medical Sciences, Catholic University of Cuyo, San Juan, Argentina; Neurogenetics Laboratory, Universidade Federal do ABC, São Bernardo do Campo, SP, Brazil
| | - Lívia Clemente Motta-Teixeira
- Neuroscience and Behaviour Laboratory, Department of Physiology, Institute of Biosciences, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Juliane Midori Ikebara
- Neurogenetics Laboratory, Universidade Federal do ABC, São Bernardo do Campo, SP, Brazil
| | | | - Aline Vilar Machado-Nils
- Neuroscience and Behaviour Laboratory, Department of Physiology, Institute of Biosciences, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Vitor Yonamine Lee
- Neuroscience Laboratory, Department of Anatomy, Institute of Biomedical Sciences, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Isabelle Diccini
- Neuroscience Laboratory, Department of Anatomy, Institute of Biomedical Sciences, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Bruna Petrucelli Arruda
- Neuroscience Laboratory, Department of Anatomy, Institute of Biomedical Sciences, Universidade de São Paulo, São Paulo, SP, Brazil; Neurogenetics Laboratory, Universidade Federal do ABC, São Bernardo do Campo, SP, Brazil
| | | | | | | | - Reza Raeisossadati
- Neurogenetics Laboratory, Universidade Federal do ABC, São Bernardo do Campo, SP, Brazil
| | - Martin Bruno
- Biomedical Sciences Institute, Faculty of Medical Sciences, Catholic University of Cuyo, San Juan, Argentina; National Council of Scientific and Technical Research (CONICET), Argentina
| | - Luiz Fernando Takase
- Department of Morphology and Pathology, Biological Sciences and Health Center, Universidade Federal de São Carlos, São Carlos, Brazil
| | | | - Maria Inês Nogueira
- Neuroscience Laboratory, Department of Anatomy, Institute of Biomedical Sciences, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Gilberto Fernando Xavier
- Neuroscience and Behaviour Laboratory, Department of Physiology, Institute of Biosciences, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Silvia Honda Takada
- Neurogenetics Laboratory, Universidade Federal do ABC, São Bernardo do Campo, SP, Brazil.
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Mazuir E, Fricker D, Sol-Foulon N. Neuron-Oligodendrocyte Communication in Myelination of Cortical GABAergic Cells. Life (Basel) 2021; 11:216. [PMID: 33803153 PMCID: PMC7999565 DOI: 10.3390/life11030216] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 03/01/2021] [Accepted: 03/04/2021] [Indexed: 11/17/2022] Open
Abstract
Axonal myelination by oligodendrocytes increases the speed and reliability of action potential propagation, and so plays a pivotal role in cortical information processing. The extent and profile of myelination vary between different cortical layers and groups of neurons. Two subtypes of cortical GABAergic neurons are myelinated: fast-spiking parvalbumin-expressing cells and somatostatin-containing cells. The expression of pre-nodes on the axon of these inhibitory cells before myelination illuminates communication between oligodendrocytes and neurons. We explore the consequences of myelination for action potential propagation, for patterns of neuronal connectivity and for the expression of behavioral plasticity.
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Affiliation(s)
- Elisa Mazuir
- Inserm, CNRS, Paris Brain Institute, ICM, Sorbonne University, Pitié-Salpêtrière Hospital, F-75013 Paris, France
| | - Desdemona Fricker
- CNRS UMR 8002, Integrative Neuroscience and Cognition Center, Université de Paris, F-75006 Paris, France
| | - Nathalie Sol-Foulon
- Inserm, CNRS, Paris Brain Institute, ICM, Sorbonne University, Pitié-Salpêtrière Hospital, F-75013 Paris, France
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McMartin L, Kiraly M, Heller HC, Madison DV, Ruby NF. Disruption of circadian timing increases synaptic inhibition and reduces cholinergic responsiveness in the dentate gyrus. Hippocampus 2021; 31:422-434. [PMID: 33439521 PMCID: PMC8048473 DOI: 10.1002/hipo.23301] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Revised: 12/28/2020] [Accepted: 01/02/2021] [Indexed: 12/11/2022]
Abstract
We investigated synaptic mechanisms in the hippocampus that could explain how loss of circadian timing leads to impairments in spatial and recognition memory. Experiments were performed in hippocampal slices from Siberian hamsters (Phodopus sungorus) because, unlike mice and rats, their circadian rhythms are easily eliminated without modifications to their genome and without surgical manipulations, thereby leaving neuronal circuits intact. Recordings of excitatory postsynaptic field potentials and population spikes in area CA1 and dentate gyrus granule cells revealed no effect of circadian arrhythmia on basic functions of synaptic circuitry, including long-term potentiation. However, dentate granule cells from circadian-arrhythmic animals maintained a more depolarized resting membrane potential than cells from circadian-intact animals; a significantly greater proportion of these cells depolarized in response to the cholinergic agonist carbachol (10 μM), and did so by increasing their membrane potential three-fold greater than cells from the control (entrained) group. Dentate granule cells from arrhythmic animals also exhibited higher levels of tonic inhibition, as measured by the frequency of spontaneous inhibitory postsynaptic potentials. Carbachol also decreased stimulus-evoked synaptic excitation in dentate granule cells from both intact and arrhythmic animals as expected, but reduced stimulus-evoked synaptic inhibition only in cells from control hamsters. These findings show that loss of circadian timing is accompanied by greater tonic inhibition, and increased synaptic inhibition in response to muscarinic receptor activation in dentate granule cells. Increased inhibition would likely attenuate excitation in dentate-CA3 microcircuits, which in turn might explain the spatial memory deficits previously observed in circadian-arrhythmic hamsters.
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Affiliation(s)
- Laura McMartin
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California, USA
| | - Marianna Kiraly
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California, USA
| | - H Craig Heller
- Biology Department, Stanford University, Stanford, California, USA
| | - Daniel V Madison
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California, USA
| | - Norman F Ruby
- Biology Department, Stanford University, Stanford, California, USA
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Hippocampal subfield abnormalities and memory functioning in children with fetal alcohol Spectrum disorders. Neurotoxicol Teratol 2020; 83:106944. [PMID: 33232797 DOI: 10.1016/j.ntt.2020.106944] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 11/06/2020] [Accepted: 11/15/2020] [Indexed: 01/26/2023]
Abstract
BACKGROUND Prenatal alcohol exposure (PAE) affects early brain development and has been associated with hippocampal damage. Animal models of PAE have suggested that some subfields of the hippocampus may be more susceptible to damage than others. Recent advances in structural MRI processing now allow us to examine the morphology of hippocampal subfields in humans with PAE. METHOD Structural MRI scans were collected from 40 children with PAE and 39 typically developing children (ages 8-16). The images were processed using the Human Connectome Project Minimal Preprocessing Pipeline (v4.0.1) and the Hippocampal Subfields package (v21) from FreeSurfer. Using a large dataset of typically developing children enrolled in the Human Connectome Project in Development (HCP-D) for normative standards, we computed age-specific volumetric z-scores for our two samples. Using these norm-adjusted hippocampal subfield volumes, comparisons were performed between children with PAE and typically developing children, controlling for total intracranial volume. Lastly, we investigated whether subfield volumes correlated with episodic memory (i.e., Picture Sequence Memory test of the NIH toolbox). RESULTS Five subfields had significantly smaller adjusted volumes in children with PAE than in typically developing controls: CA1, CA4, subiculum, presubiculum, and the hippocampal tail. Subfield volumes were not significantly correlated with episodic memory. CONCLUSIONS The results suggest that several regions of the hippocampus may be particularly affected by PAE. The finding of smaller CA1 volumes parallels previous reports in rodent models. The novel findings of decreased volume in the subicular cortex, CA4 and the hippocampal tail suggest avenues for future research.
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Effects of Transient Receptor Potential Cation 5 (TRPC5) Inhibitor, NU6027, on Hippocampal Neuronal Death after Traumatic Brain Injury. Int J Mol Sci 2020; 21:ijms21218256. [PMID: 33158109 PMCID: PMC7662546 DOI: 10.3390/ijms21218256] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 10/30/2020] [Accepted: 11/03/2020] [Indexed: 12/20/2022] Open
Abstract
Traumatic brain injury (TBI) can cause physical, cognitive, social, and behavioral changes that can lead to permanent disability or death. After primary brain injury, translocated free zinc can accumulate in neurons and lead to secondary events such as oxidative stress, inflammation, edema, swelling, and cognitive impairment. Under pathological conditions, such as ischemia and TBI, excessive zinc release, and accumulation occurs in neurons. Based on previous research, it hypothesized that calcium as well as zinc would be influx into the TRPC5 channel. Therefore, we hypothesized that the suppression of TRPC5 would prevent neuronal cell death by reducing the influx of zinc and calcium. To test our hypothesis, we used a TBI animal model. After the TBI, we immediately injected NU6027 (1 mg/kg, intraperitoneal), TRPC5 inhibitor, and then sacrificed animals 24 h later. We conducted Fluoro-Jade B (FJB) staining to confirm the presence of degenerating neurons in the hippocampal cornus ammonis 3 (CA3). After the TBI, the degenerating neuronal cell count was decreased in the NU6027-treated group compared with the vehicle-treated group. Our findings suggest that the suppression of TRPC5 can open a new therapeutic window for a reduction of the neuronal death that may occur after TBI.
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Peyrache A, Seibt J. A mechanism for learning with sleep spindles. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190230. [PMID: 32248788 PMCID: PMC7209910 DOI: 10.1098/rstb.2019.0230] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/29/2019] [Indexed: 12/21/2022] Open
Abstract
Spindles are ubiquitous oscillations during non-rapid eye movement (NREM) sleep. A growing body of evidence points to a possible link with learning and memory, and the underlying mechanisms are now starting to be unveiled. Specifically, spindles are associated with increased dendritic activity and high intracellular calcium levels, a situation favourable to plasticity, as well as with control of spiking output by feed-forward inhibition. During spindles, thalamocortical networks become unresponsive to inputs, thus potentially preventing interference between memory-related internal information processing and extrinsic signals. At the system level, spindles are co-modulated with other major NREM oscillations, including hippocampal sharp wave-ripples (SWRs) and neocortical slow waves, both previously shown to be associated with learning and memory. The sequential occurrence of reactivation at the time of SWRs followed by neuronal plasticity-promoting spindles is a possible mechanism to explain NREM sleep-dependent consolidation of memories. This article is part of the Theo Murphy meeting issue 'Memory reactivation: replaying events past, present and future'.
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Affiliation(s)
- Adrien Peyrache
- Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada, H3A 1A1
| | - Julie Seibt
- Surrey Sleep Research Centre, University of Surrey, Guildford, UK
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30
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Dentate gyrus circuits for encoding, retrieval and discrimination of episodic memories. Nat Rev Neurosci 2020; 21:153-168. [PMID: 32042144 DOI: 10.1038/s41583-019-0260-z] [Citation(s) in RCA: 186] [Impact Index Per Article: 46.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/18/2019] [Indexed: 12/19/2022]
Abstract
The dentate gyrus (DG) has a key role in hippocampal memory formation. Intriguingly, DG lesions impair many, but not all, hippocampus-dependent mnemonic functions, indicating that the rest of the hippocampus (CA1-CA3) can operate autonomously under certain conditions. An extensive body of theoretical work has proposed how the architectural elements and various cell types of the DG may underlie its function in cognition. Recent studies recorded and manipulated the activity of different neuron types in the DG during memory tasks and have provided exciting new insights into the mechanisms of DG computational processes, particularly for the encoding, retrieval and discrimination of similar memories. Here, we review these DG-dependent mnemonic functions in light of the new findings and explore mechanistic links between the cellular and network properties of, and the computations performed by, the DG.
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31
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Moderate protective effect of Kyotorphin against the late consequences of intracerebroventricular streptozotocin model of Alzheimer's disease. Amino Acids 2019; 51:1501-1513. [PMID: 31520285 DOI: 10.1007/s00726-019-02784-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 08/30/2019] [Indexed: 01/08/2023]
Abstract
The established decrease in the level of endogenous kyotorphin (KTP) into the cerebrospinal fluid of patients with an advanced stage of Alzheimer's disease (AD) and the found neuroprotective activity of KTP suggested its participation in the pathophysiology of the disease. We aimed to study the effects of subchronic intracerebroventricular (ICV) treatment (14 days) with KTP on the behavioral, biochemical and histological changes in rats with streptozotocin (STZ-ICV)-induced model of sporadic AD (sAD). Three months after the administration of STZ-ICV, rats developed increased locomotor activity, decreased level of anxiety, impaired spatial and working memory. Histological data from the STZ-ICV group demonstrated decreased number of neurons in the CA1 and CA3 subfields of the hippocampus. The STZ-ICV group was characterized with a decrease of total protein content in the hippocampus and the prefrontal cortex as well as increased levels of the carbonylated proteins in the hippocampus. KTP treatment of STZ-ICV rats normalized anxiety level and regained object recognition memory. KTP abolished the protein loss in prefrontal cortex and decrease the neuronal loss in the CA3 subfield of the hippocampus. STZ-ICV rats, treated with KTP, did not show significant changes in the levels of the carbonylated proteins in specific brain structures or in motor activity and spatial memory compared to the saline-treated STZ-ICV group. Our data show a moderate and selective protective effect of a subchronic ICV administration of the dipeptide KTP on the pathological changes induced by an experimental model of sAD in rats.
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32
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Molecular and Cellular Mechanisms Underlying Somatostatin-Based Signaling in Two Model Neural Networks, the Retina and the Hippocampus. Int J Mol Sci 2019; 20:ijms20102506. [PMID: 31117258 PMCID: PMC6566141 DOI: 10.3390/ijms20102506] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 05/16/2019] [Accepted: 05/20/2019] [Indexed: 02/06/2023] Open
Abstract
Neural inhibition plays a key role in determining the specific computational tasks of different brain circuitries. This functional "braking" activity is provided by inhibitory interneurons that use different neurochemicals for signaling. One of these substances, somatostatin, is found in several neural networks, raising questions about the significance of its widespread occurrence and usage. Here, we address this issue by analyzing the somatostatinergic system in two regions of the central nervous system: the retina and the hippocampus. By comparing the available information on these structures, we identify common motifs in the action of somatostatin that may explain its involvement in such diverse circuitries. The emerging concept is that somatostatin-based signaling, through conserved molecular and cellular mechanisms, allows neural networks to operate correctly.
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33
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Fujisawa S, Kazama H. Circuits and neural dynamics underlying behavior. Neurosci Res 2019; 140:1-2. [PMID: 30824041 DOI: 10.1016/j.neures.2019.01.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Shigeyoshi Fujisawa
- RIKEN Center for Brain Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
| | - Hokto Kazama
- RIKEN Center for Brain Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
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