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Cheng HY, Fournier DI, Todd TP. Retrosplenial cortex and aversive conditioning. Front Behav Neurosci 2024; 18:1341705. [PMID: 38983870 PMCID: PMC11232490 DOI: 10.3389/fnbeh.2024.1341705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 02/26/2024] [Indexed: 07/11/2024] Open
Abstract
The retrosplenial cortex (RSC) is well-known for its contribution to episodic memory, as well as contextual and spatial learning and memory. However, two literatures have also emerged examining the role of the RSC in aversive conditioning. The purpose of this manuscript is to review, and attempt to integrate, these two literatures. We focus on studies in which discrete cues, such as tones, predict the occurrence of aversive outcomes, such as mild shocks. Using both electrophysiological recordings and lesion methods, the first literature has examined RSC contributions to discriminative avoidance conditioning. The second, and more recent literature, has focused on the role of the RSC in Pavlovian fear conditioning. We discuss both literatures in terms of the type of information processed by the RSC, the role of the RSC in memory storage, and how the aversive conditioning literature might be consistent with a role for the RSC in contextual learning and memory.
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Affiliation(s)
| | | | - Travis P. Todd
- Department of Psychological Science, University of Vermont, Burlington, VT, United States
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2
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Pogledic I, Bobić‐Rasonja M, Mitter C, Štajduhar A, Schwartz E, Milković‐Periša M, Baltzer PA, Lequin M, Krampl‐Bettelheim E, Kasprian G, Judaš M, Prayer D, Jovanov‐Milosevic N. Fetal indusium griseum is a possible biomarker of the regularity of brain midline development in 3T MR imaging: A retrospective observational study. Acta Obstet Gynecol Scand 2024; 103:897-906. [PMID: 38339766 PMCID: PMC11019519 DOI: 10.1111/aogs.14781] [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: 09/21/2023] [Revised: 12/04/2023] [Accepted: 01/03/2024] [Indexed: 02/12/2024]
Abstract
INTRODUCTION This study aimed to assess the visibility of the indusium griseum (IG) in magnetic resonance (MR) scans of the human fetal brain and to evaluate its reliability as an imaging biomarker of the normality of brain midline development. MATERIAL AND METHODS The retrospective observational study encompassed T2-w 3T MR images from 90 post-mortem fetal brains and immunohistochemical sections from 41 fetal brains (16-40 gestational weeks) without cerebral pathology. Three raters independently inspected and evaluated the visibility of IG in post-mortem and in vivo MR scans. Weighted kappa statistics and regression analysis were used to determine inter- and intra-rater agreement and the type and strength of the association of IG visibility with gestational age. RESULTS The visibility of the IG was the highest between the 25 and 30 gestational week period, with a very good inter-rater variability (kappa 0.623-0.709) and excellent intra-rater variability (kappa 0.81-0.93). The immunochemical analysis of the histoarchitecture of IG discloses the expression of highly hydrated extracellular molecules in IG as the substrate of higher signal intensity and best visibility of IG during the mid-fetal period. CONCLUSIONS The knowledge of developmental brain histology and fetal age allows us to predict the IG-visibility in magnetic resonance imaging (MRI) and use it as a biomarker to evaluate the morphogenesis of the brain midline. As a biomarker, IG is significant for post-mortem pathological examination by MRI. Therefore, in the clinical in vivo imaging examination, IG should be anticipated when an assessment of the brain midline structures is needed in mid-gestation, including corpus callosum thickness measurements.
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Affiliation(s)
- Ivana Pogledic
- Division of Neuroradiology and Musculoskeletal Radiology, Department of Biomedical Imaging and Image‐guided Therapy, Allgemeines KrankenhausMedical University of ViennaViennaAustria
| | - Mihaela Bobić‐Rasonja
- Department of BiologySchool of Medicine, University of ZagrebZagrebCroatia
- Croatian Institute for Brain Research, Scientific Center of Excellence for Basic, Clinical and Translational NeuroscienceSchool of Medicine University of ZagrebZagrebCroatia
| | - Christian Mitter
- Division of Neuroradiology and Musculoskeletal Radiology, Department of Biomedical Imaging and Image‐guided Therapy, Allgemeines KrankenhausMedical University of ViennaViennaAustria
- Department of Systematic Anatomy, Center for Anatomy and Cell BiologyMedical University of ViennaViennaAustria
| | - Andrija Štajduhar
- Croatian Institute for Brain Research, Scientific Center of Excellence for Basic, Clinical and Translational NeuroscienceSchool of Medicine University of ZagrebZagrebCroatia
- School of MedicineSchool of Public Health “Andrija Štampar” University of ZagrebZagrebCroatia
| | - Ernst Schwartz
- Computational Imaging Research Lab, Department of Biomedical Imaging and Image‐Guided TherapyMedical University of ViennaViennaAustria
| | - Marija Milković‐Periša
- Department of Pathology and Cytology, School of MedicineUniversity Hospital Center Zagreb, University of ZagrebZagrebCroatia
| | - Pascal A. Baltzer
- Division of Neuroradiology and Musculoskeletal Radiology, Department of Biomedical Imaging and Image‐guided Therapy, Allgemeines KrankenhausMedical University of ViennaViennaAustria
| | - Maarten Lequin
- Department of RadiologyUniversity Medical Center UtrechtUtrechtThe Netherlands
| | | | - Gregor Kasprian
- Division of Neuroradiology and Musculoskeletal Radiology, Department of Biomedical Imaging and Image‐guided Therapy, Allgemeines KrankenhausMedical University of ViennaViennaAustria
| | - Miloš Judaš
- Croatian Institute for Brain Research, Scientific Center of Excellence for Basic, Clinical and Translational NeuroscienceSchool of Medicine University of ZagrebZagrebCroatia
| | - Daniela Prayer
- Division of Neuroradiology and Musculoskeletal Radiology, Department of Biomedical Imaging and Image‐guided Therapy, Allgemeines KrankenhausMedical University of ViennaViennaAustria
| | - Natasa Jovanov‐Milosevic
- Department of BiologySchool of Medicine, University of ZagrebZagrebCroatia
- Croatian Institute for Brain Research, Scientific Center of Excellence for Basic, Clinical and Translational NeuroscienceSchool of Medicine University of ZagrebZagrebCroatia
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Hoffman C, Cheng J, Morales R, Ji D, Dabaghian Y. Altered patterning of neural activity in a tauopathy mouse model. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.23.586417. [PMID: 38585991 PMCID: PMC10996513 DOI: 10.1101/2024.03.23.586417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
Alzheimer's disease (AD) is a complex neurodegenerative condition that manifests at multiple levels and involves a spectrum of abnormalities ranging from the cellular to cognitive. Here, we investigate the impact of AD-related tau-pathology on hippocampal circuits in mice engaged in spatial navigation, and study changes of neuronal firing and dynamics of extracellular fields. While most studies are based on analyzing instantaneous or time-averaged characteristics of neuronal activity, we focus on intermediate timescales-spike trains and waveforms of oscillatory potentials, which we consider as single entities. We find that, in healthy mice, spike arrangements and wave patterns (series of crests or troughs) are coupled to the animal's location, speed, and acceleration. In contrast, in tau-mice, neural activity is structurally disarrayed: brainwave cadence is detached from locomotion, spatial selectivity is lost, the spike flow is scrambled. Importantly, these alterations start early and accumulate with age, which exposes progressive disinvolvement the hippocampus circuit in spatial navigation. These features highlight qualitatively different neurodynamics than the ones provided by conventional analyses, and are more salient, thus revealing a new level of the hippocampal circuit disruptions.
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Affiliation(s)
- C Hoffman
- Department of Neurology, The University of Texas McGovern Medical School, 6431 Fannin St, Houston, TX 77030
| | - J Cheng
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030
| | - R Morales
- Department of Neurology, The University of Texas McGovern Medical School, 6431 Fannin St, Houston, TX 77030
| | - D Ji
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030
| | - Y Dabaghian
- Department of Neurology, The University of Texas McGovern Medical School, 6431 Fannin St, Houston, TX 77030
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Takács V, Bardóczi Z, Orosz Á, Major A, Tar L, Berki P, Papp P, Mayer MI, Sebők H, Zsolt L, Sos KE, Káli S, Freund TF, Nyiri G. Synaptic and dendritic architecture of different types of hippocampal somatostatin interneurons. PLoS Biol 2024; 22:e3002539. [PMID: 38470935 PMCID: PMC10959371 DOI: 10.1371/journal.pbio.3002539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2023] [Revised: 03/22/2024] [Accepted: 02/06/2024] [Indexed: 03/14/2024] Open
Abstract
GABAergic inhibitory neurons fundamentally shape the activity and plasticity of cortical circuits. A major subset of these neurons contains somatostatin (SOM); these cells play crucial roles in neuroplasticity, learning, and memory in many brain areas including the hippocampus, and are implicated in several neuropsychiatric diseases and neurodegenerative disorders. Two main types of SOM-containing cells in area CA1 of the hippocampus are oriens-lacunosum-moleculare (OLM) cells and hippocampo-septal (HS) cells. These cell types show many similarities in their soma-dendritic architecture, but they have different axonal targets, display different activity patterns in vivo, and are thought to have distinct network functions. However, a complete understanding of the functional roles of these interneurons requires a precise description of their intrinsic computational properties and their synaptic interactions. In the current study we generated, analyzed, and make available several key data sets that enable a quantitative comparison of various anatomical and physiological properties of OLM and HS cells in mouse. The data set includes detailed scanning electron microscopy (SEM)-based 3D reconstructions of OLM and HS cells along with their excitatory and inhibitory synaptic inputs. Combining this core data set with other anatomical data, patch-clamp electrophysiology, and compartmental modeling, we examined the precise morphological structure, inputs, outputs, and basic physiological properties of these cells. Our results highlight key differences between OLM and HS cells, particularly regarding the density and distribution of their synaptic inputs and mitochondria. For example, we estimated that an OLM cell receives about 8,400, whereas an HS cell about 15,600 synaptic inputs, about 16% of which are GABAergic. Our data and models provide insight into the possible basis of the different functionality of OLM and HS cell types and supply essential information for more detailed functional models of these neurons and the hippocampal network.
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Affiliation(s)
- Virág Takács
- Laboratory of Cerebral Cortex Research, HUN-REN Institute of Experimental Medicine, Budapest, Hungary
| | - Zsuzsanna Bardóczi
- Laboratory of Cerebral Cortex Research, HUN-REN Institute of Experimental Medicine, Budapest, Hungary
| | - Áron Orosz
- Laboratory of Cerebral Cortex Research, HUN-REN Institute of Experimental Medicine, Budapest, Hungary
- János Szentágothai Doctoral School of Neurosciences, Semmelweis University, Budapest, Hungary
| | - Abel Major
- Laboratory of Cerebral Cortex Research, HUN-REN Institute of Experimental Medicine, Budapest, Hungary
| | - Luca Tar
- Laboratory of Cerebral Cortex Research, HUN-REN Institute of Experimental Medicine, Budapest, Hungary
- Roska Tamás Doctoral School of Sciences and Technology, Pázmány Péter Catholic University, Budapest, Hungary
| | - Péter Berki
- Laboratory of Cerebral Cortex Research, HUN-REN Institute of Experimental Medicine, Budapest, Hungary
- János Szentágothai Doctoral School of Neurosciences, Semmelweis University, Budapest, Hungary
| | - Péter Papp
- Laboratory of Cerebral Cortex Research, HUN-REN Institute of Experimental Medicine, Budapest, Hungary
| | - Márton I. Mayer
- Laboratory of Cerebral Cortex Research, HUN-REN Institute of Experimental Medicine, Budapest, Hungary
- János Szentágothai Doctoral School of Neurosciences, Semmelweis University, Budapest, Hungary
| | - Hunor Sebők
- Laboratory of Cerebral Cortex Research, HUN-REN Institute of Experimental Medicine, Budapest, Hungary
| | - Luca Zsolt
- Laboratory of Cerebral Cortex Research, HUN-REN Institute of Experimental Medicine, Budapest, Hungary
| | - Katalin E. Sos
- Laboratory of Cerebral Cortex Research, HUN-REN Institute of Experimental Medicine, Budapest, Hungary
- János Szentágothai Doctoral School of Neurosciences, Semmelweis University, Budapest, Hungary
| | - Szabolcs Káli
- Laboratory of Cerebral Cortex Research, HUN-REN Institute of Experimental Medicine, Budapest, Hungary
| | - Tamás F. Freund
- Laboratory of Cerebral Cortex Research, HUN-REN Institute of Experimental Medicine, Budapest, Hungary
| | - Gábor Nyiri
- Laboratory of Cerebral Cortex Research, HUN-REN Institute of Experimental Medicine, Budapest, Hungary
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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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Robert V, O'Neil K, Rashid SK, Johnson CD, De La Torre RG, Zemelman BV, Clopath C, Basu J. Entorhinal cortex glutamatergic and GABAergic projections bidirectionally control discrimination and generalization of hippocampal representations. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.08.566107. [PMID: 37986793 PMCID: PMC10659280 DOI: 10.1101/2023.11.08.566107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
Discrimination and generalization are crucial brain-wide functions for memory and object recognition that utilize pattern separation and completion computations. Circuit mechanisms supporting these operations remain enigmatic. We show lateral entorhinal cortex glutamatergic (LEC GLU ) and GABAergic (LEC GABA ) projections are essential for object recognition memory. Silencing LEC GLU during in vivo two-photon imaging increased the population of active CA3 pyramidal cells but decreased activity rates, suggesting a sparse coding function through local inhibition. Silencing LEC GLU also decreased place cell remapping between different environments validating this circuit drives pattern separation and context discrimination. Optogenetic circuit mapping confirmed that LEC GLU drives dominant feedforward inhibition to prevent CA3 somatic and dendritic spikes. However, conjunctively active LEC GABA suppresses this local inhibition to disinhibit CA3 pyramidal neuron soma and selectively boost integrative output of LEC and CA3 recurrent network. LEC GABA thus promotes pattern completion and context generalization. Indeed, without this disinhibitory input, CA3 place maps show decreased similarity between contexts. Our findings provide circuit mechanisms whereby long-range glutamatergic and GABAergic cortico-hippocampal inputs bidirectionally modulate pattern separation and completion, providing neuronal representations with a dynamic range for context discrimination and generalization.
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Tzilivaki A, Tukker JJ, Maier N, Poirazi P, Sammons RP, Schmitz D. Hippocampal GABAergic interneurons and memory. Neuron 2023; 111:3154-3175. [PMID: 37467748 PMCID: PMC10593603 DOI: 10.1016/j.neuron.2023.06.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 01/04/2023] [Accepted: 06/21/2023] [Indexed: 07/21/2023]
Abstract
One of the most captivating questions in neuroscience revolves around the brain's ability to efficiently and durably capture and store information. It must process continuous input from sensory organs while also encoding memories that can persist throughout a lifetime. What are the cellular-, subcellular-, and network-level mechanisms that underlie this remarkable capacity for long-term information storage? Furthermore, what contributions do distinct types of GABAergic interneurons make to this process? As the hippocampus plays a pivotal role in memory, our review focuses on three aspects: (1) delineation of hippocampal interneuron types and their connectivity, (2) interneuron plasticity, and (3) activity patterns of interneurons during memory-related rhythms, including the role of long-range interneurons and disinhibition. We explore how these three elements, together showcasing the remarkable diversity of inhibitory circuits, shape the processing of memories in the hippocampus.
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Affiliation(s)
- Alexandra Tzilivaki
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität Berlin, and Berlin Institute of Health, Neuroscience Research Center, 10117 Berlin, Germany; Einstein Center for Neurosciences, Chariteplatz 1, 10117 Berlin, Germany; NeuroCure Cluster of Excellence, Chariteplatz 1, 10117 Berlin, Germany
| | - John J Tukker
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität Berlin, and Berlin Institute of Health, Neuroscience Research Center, 10117 Berlin, Germany; German Center for Neurodegenerative Diseases (DZNE), 10117 Berlin, Germany
| | - Nikolaus Maier
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität Berlin, and Berlin Institute of Health, Neuroscience Research Center, 10117 Berlin, Germany
| | - Panayiota Poirazi
- Foundation for Research and Technology Hellas (FORTH), Institute of Molecular Biology and Biotechnology (IMBB), N. Plastira 100, Heraklion, Crete, Greece
| | - Rosanna P Sammons
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität Berlin, and Berlin Institute of Health, Neuroscience Research Center, 10117 Berlin, Germany
| | - Dietmar Schmitz
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität Berlin, and Berlin Institute of Health, Neuroscience Research Center, 10117 Berlin, Germany; Einstein Center for Neurosciences, Chariteplatz 1, 10117 Berlin, Germany; NeuroCure Cluster of Excellence, Chariteplatz 1, 10117 Berlin, Germany; German Center for Neurodegenerative Diseases (DZNE), 10117 Berlin, Germany; Bernstein Center for Computational Neuroscience, Humboldt-Universität zu Berlin, Philippstrasse. 13, 10115 Berlin, Germany; Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Robert-Rössle-Straße 10, 13125 Berlin, Germany.
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Pinatel D, Pearlstein E, Bonetto G, Goutebroze L, Karagogeos D, Crepel V, Faivre-Sarrailh C. A class-specific effect of dysmyelination on the excitability of hippocampal interneurons. eLife 2023; 12:e86469. [PMID: 37843188 PMCID: PMC10617988 DOI: 10.7554/elife.86469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 10/13/2023] [Indexed: 10/17/2023] Open
Abstract
The role of myelination for axonal conduction is well-established in projection neurons but little is known about its significance in GABAergic interneurons. Myelination is discontinuous along interneuron axons and the mechanisms controlling myelin patterning and segregation of ion channels at the nodes of Ranvier have not been elucidated. Protein 4.1B is implicated in the organization of the nodes of Ranvier as a linker between paranodal and juxtaparanodal membrane proteins to the spectrin cytoskeleton. In the present study, 4.1B KO mice are used as a genetic model to analyze the functional role of myelin in Lhx6-positive parvalbumin (PV) and somatostatin (SST) neurons, two major classes of GABAergic neurons in the hippocampus. We show that 4.1B-deficiency induces disruption of juxtaparanodal K+ channel clustering and mislocalization of nodal or heminodal Na+ channels. Strikingly, 4.1B-deficiency causes loss of myelin in GABAergic axons in the hippocampus. In particular, stratum oriens SST cells display severe axonal dysmyelination and a reduced excitability. This reduced excitability is associated with a decrease in occurrence probability of small amplitude synaptic inhibitory events on pyramidal cells. In contrast, stratum pyramidale fast-spiking PV cells do not appear affected. In conclusion, our results indicate a class-specific effect of dysmyelination on the excitability of hippocampal interneurons associated with a functional alteration of inhibitory drive.
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Affiliation(s)
| | | | | | - Laurence Goutebroze
- INSERM, Institut du Fer à Moulin, Sorbonne Université, Faculté des Sciences et IngénierieParisFrance
| | - Domna Karagogeos
- Department of Basic Sciences, University of Crete Medical School and Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology, University of CreteHeraklionGreece
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Hector A, Provost C, Delignat-Lavaud B, Bouamira K, Menaouar CA, Mongrain V, Brouillette J. Hippocampal injections of soluble amyloid-beta oligomers alter electroencephalographic activity during wake and slow-wave sleep in rats. Alzheimers Res Ther 2023; 15:174. [PMID: 37833786 PMCID: PMC10571363 DOI: 10.1186/s13195-023-01316-4] [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: 07/12/2023] [Accepted: 09/26/2023] [Indexed: 10/15/2023]
Abstract
BACKGROUND Soluble amyloid-beta oligomers (Aβo) begin to accumulate in the human brain one to two decades before a clinical diagnosis of Alzheimer's disease (AD). The literature supports that soluble Aβo are implicated in synapse and neuronal losses in the brain regions such as the hippocampus. This region importantly contributes to explicit memory, the first type of memory affected in AD. During AD preclinical and prodromal stages, people are also experiencing wake/sleep alterations such as insomnia (e.g., difficulty initiating sleep, decreased sleep duration), excessive daytime sleepiness, and sleep schedule modifications. In addition, changes in electroencephalographic (EEG) activity during wake and sleep have been reported in AD patients and animal models. However, the specific contribution of Aβo to wake/sleep alterations is poorly understood and was investigated in the present study. METHODS Chronic hippocampal injections of soluble Aβo were conducted in male rats and combined with EEG recording to determine the progressive impact of Aβ pathology specifically on wake/sleep architecture and EEG activity. Bilateral injections were conducted for 6 consecutive days, and EEG acquisition was done before, during, and after Aβo injections. Immunohistochemistry was used to assess neuron numbers in the hippocampal dentate gyrus (DG). RESULTS Aβo injections did not affect the time spent in wakefulness, slow wave sleep (SWS), and paradoxical sleep but altered EEG activity during wake and SWS. More precisely, Aβo increased slow-wave activity (SWA; 0.5-5 Hz) and low-beta activity (16-20 Hz) during wake and decreased theta (5-9 Hz) and alpha (9-12 Hz) activities during SWS. Moreover, the theta activity/SWA ratio during wake and SWS was decreased by Aβo. These effects were significant only after 6 days of Aβo injections and were found with alterations in neuron counts in the DG. CONCLUSIONS We found multiple modifications of the wake and SWS EEG following Aβo delivery to the hippocampus. These findings expose a specific EEG signature of Aβ pathology and can serve the development of non-invasive and cost-effective markers for the early diagnosis of AD or other amyloid-related diseases.
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Affiliation(s)
- Audrey Hector
- Department of Pharmacology and Physiology, Université de Montréal, Montréal, Québec, Canada
- Center for Advanced Research in Sleep Medicine, CIUSSS-NIM, Montréal, Québec, Canada
- Centre de Recherche, Centre Hospitalier de l'Université de Montréal, Montréal, Québec, Canada
| | - Chloé Provost
- Center for Advanced Research in Sleep Medicine, CIUSSS-NIM, Montréal, Québec, Canada
| | - Benoît Delignat-Lavaud
- Center for Advanced Research in Sleep Medicine, CIUSSS-NIM, Montréal, Québec, Canada
- Centre de Recherche, Centre Hospitalier de l'Université de Montréal, Montréal, Québec, Canada
| | - Khadija Bouamira
- Center for Advanced Research in Sleep Medicine, CIUSSS-NIM, Montréal, Québec, Canada
| | | | - Valérie Mongrain
- Center for Advanced Research in Sleep Medicine, CIUSSS-NIM, Montréal, Québec, Canada.
- Centre de Recherche, Centre Hospitalier de l'Université de Montréal, Montréal, Québec, Canada.
- Department of Neuroscience, Université de Montréal, Montréal, Québec, Canada.
| | - Jonathan Brouillette
- Department of Pharmacology and Physiology, Université de Montréal, Montréal, Québec, Canada.
- Center for Advanced Research in Sleep Medicine, CIUSSS-NIM, Montréal, Québec, Canada.
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10
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Gamache J, Gingerich D, Shwab EK, Barrera J, Garrett ME, Hume C, Crawford GE, Ashley-Koch AE, Chiba-Falek O. Integrative single-nucleus multi-omics analysis prioritizes candidate cis and trans regulatory networks and their target genes in Alzheimer's disease brains. Cell Biosci 2023; 13:185. [PMID: 37789374 PMCID: PMC10546724 DOI: 10.1186/s13578-023-01120-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Accepted: 08/30/2023] [Indexed: 10/05/2023] Open
Abstract
BACKGROUND The genetic underpinnings of late-onset Alzheimer's disease (LOAD) are yet to be fully elucidated. Although numerous LOAD-associated loci have been discovered, the causal variants and their target genes remain largely unknown. Since the brain is composed of heterogenous cell subtypes, it is imperative to study the brain on a cell subtype specific level to explore the biological processes underlying LOAD. METHODS Here, we present the largest parallel single-nucleus (sn) multi-omics study to simultaneously profile gene expression (snRNA-seq) and chromatin accessibility (snATAC-seq) to date, using nuclei from 12 normal and 12 LOAD brains. We identified cell subtype clusters based on gene expression and chromatin accessibility profiles and characterized cell subtype-specific LOAD-associated differentially expressed genes (DEGs), differentially accessible peaks (DAPs) and cis co-accessibility networks (CCANs). RESULTS Integrative analysis defined disease-relevant CCANs in multiple cell subtypes and discovered LOAD-associated cell subtype-specific candidate cis regulatory elements (cCREs), their candidate target genes, and trans-interacting transcription factors (TFs), some of which, including ELK1, JUN, and SMAD4 in excitatory neurons, were also LOAD-DEGs. Finally, we focused on a subset of cell subtype-specific CCANs that overlap known LOAD-GWAS regions and catalogued putative functional SNPs changing the affinities of TF motifs within LOAD-cCREs linked to LOAD-DEGs, including APOE and MYO1E in a specific subtype of microglia and BIN1 in a subpopulation of oligodendrocytes. CONCLUSIONS To our knowledge, this study represents the most comprehensive systematic interrogation to date of regulatory networks and the impact of genetic variants on gene dysregulation in LOAD at a cell subtype resolution. Our findings reveal crosstalk between epigenetic, genomic, and transcriptomic determinants of LOAD pathogenesis and define catalogues of candidate genes, cCREs, and variants involved in LOAD genetic etiology and the cell subtypes in which they act to exert their pathogenic effects. Overall, these results suggest that cell subtype-specific cis-trans interactions between regulatory elements and TFs, and the genes dysregulated by these networks contribute to the development of LOAD.
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Affiliation(s)
- Julia Gamache
- Division of Translational Brain Sciences, Department of Neurology, Duke University Medical Center, DUMC Box 2900, Durham, NC, 27710, USA
- Center for Genomic and Computational Biology, Duke University Medical Center, Durham, NC, 27708, USA
| | - Daniel Gingerich
- Division of Translational Brain Sciences, Department of Neurology, Duke University Medical Center, DUMC Box 2900, Durham, NC, 27710, USA
- Center for Genomic and Computational Biology, Duke University Medical Center, Durham, NC, 27708, USA
| | - E Keats Shwab
- Division of Translational Brain Sciences, Department of Neurology, Duke University Medical Center, DUMC Box 2900, Durham, NC, 27710, USA
- Center for Genomic and Computational Biology, Duke University Medical Center, Durham, NC, 27708, USA
| | - Julio Barrera
- Division of Translational Brain Sciences, Department of Neurology, Duke University Medical Center, DUMC Box 2900, Durham, NC, 27710, USA
- Center for Genomic and Computational Biology, Duke University Medical Center, Durham, NC, 27708, USA
| | - Melanie E Garrett
- Duke Molecular Physiology Institute, Duke University Medical Center, DUMC Box 104775, Durham, NC, 27701, USA
| | - Cordelia Hume
- Division of Translational Brain Sciences, Department of Neurology, Duke University Medical Center, DUMC Box 2900, Durham, NC, 27710, USA
- Center for Genomic and Computational Biology, Duke University Medical Center, Durham, NC, 27708, USA
| | - Gregory E Crawford
- Center for Genomic and Computational Biology, Duke University Medical Center, Durham, NC, 27708, USA.
- Department of Pediatrics, Division of Medical Genetics, Duke University Medical Center, DUMC Box 3382, Durham, NC, 27708, USA.
- Center for Advanced Genomic Technologies, Duke University Medical Center, Durham, NC, 27708, USA.
| | - Allison E Ashley-Koch
- Duke Molecular Physiology Institute, Duke University Medical Center, DUMC Box 104775, Durham, NC, 27701, USA.
- Department of Medicine, Duke University Medical Center, Durham, NC, 27708, USA.
| | - Ornit Chiba-Falek
- Division of Translational Brain Sciences, Department of Neurology, Duke University Medical Center, DUMC Box 2900, Durham, NC, 27710, USA.
- Center for Genomic and Computational Biology, Duke University Medical Center, Durham, NC, 27708, USA.
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11
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Yamada J, Maeda S, Tojo M, Hayashida M, Iinuma KM, Jinno S. Altered regulation of oligodendrocytes associated with parvalbumin neurons in the ventral hippocampus underlies fear generalization in male mice. Neuropsychopharmacology 2023; 48:1668-1679. [PMID: 37277574 PMCID: PMC10516901 DOI: 10.1038/s41386-023-01611-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 05/08/2023] [Accepted: 05/15/2023] [Indexed: 06/07/2023]
Abstract
Fear generalization is a neurobiological process by which an organism interprets a novel stimulus as threatening because of its similarity to previously learned fear-inducing stimuli. Because recent studies have suggested that the communication between oligodendrocyte precursor cells (OPCs) and parvalbumin (PV)-expressing GABAergic neurons (PV neurons) may play critical roles in stress-related disorders, we examined the involvement of these cells in fear generalization. We first tested the behavioral characteristics of mouse models for conventional fear conditioning (cFC) and modified FC (mFC) with severe electric foot shocks and found that fear generalization was observed in mice treated with mFC but not in mice treated with cFC. The expression levels of genes related to OPCs, oligodendrocytes (OLs), and myelin in the ventral hippocampus were lower in mFC mice than in cFC mice. The densities of OPCs and OLs were decreased in the ventral hippocampus of mFC mice compared to cFC mice. The myelination ratios of PV neurons in the ventral hippocampus were lower in mFC mice than in cFC mice. The chemogenetic activation of PV neurons in the ventral hippocampus of mFC mice reduced fear generalization. The expression levels of genes related to OPCs, OLs, and myelin were recovered following the activation of PV neurons. Finally, the myelination ratios of PV neurons were increased after the activation of PV neurons. Our results suggest that altered regulation of OLs specifically associated with axons of PV neurons in the ventral hippocampus may underlie the generalization of remote fear memory following severe stress exposure.
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Affiliation(s)
- Jun Yamada
- Department of Anatomy and Neuroscience, Graduate School of Medical Sciences, Kyushu University, Fukuoka, 812-8582, Japan.
| | - Shoichiro Maeda
- Department of Anatomy and Neuroscience, Graduate School of Medical Sciences, Kyushu University, Fukuoka, 812-8582, Japan
| | - Miori Tojo
- Department of Anatomy and Neuroscience, Graduate School of Medical Sciences, Kyushu University, Fukuoka, 812-8582, Japan
| | - Miyuki Hayashida
- Department of Anatomy and Neuroscience, Graduate School of Medical Sciences, Kyushu University, Fukuoka, 812-8582, Japan
| | - Kyoko M Iinuma
- Department of Anatomy and Neuroscience, Graduate School of Medical Sciences, Kyushu University, Fukuoka, 812-8582, Japan
| | - Shozo Jinno
- Department of Anatomy and Neuroscience, Graduate School of Medical Sciences, Kyushu University, Fukuoka, 812-8582, Japan.
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12
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Hernández-Frausto M, Bilash OM, Masurkar AV, Basu J. Local and long-range GABAergic circuits in hippocampal area CA1 and their link to Alzheimer's disease. Front Neural Circuits 2023; 17:1223891. [PMID: 37841892 PMCID: PMC10570439 DOI: 10.3389/fncir.2023.1223891] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 09/08/2023] [Indexed: 10/17/2023] Open
Abstract
GABAergic inhibitory neurons are the principal source of inhibition in the brain. Traditionally, their role in maintaining the balance of excitation-inhibition has been emphasized. Beyond homeostatic functions, recent circuit mapping and functional manipulation studies have revealed a wide range of specific roles that GABAergic circuits play in dynamically tilting excitation-inhibition coupling across spatio-temporal scales. These span from gating of compartment- and input-specific signaling, gain modulation, shaping input-output functions and synaptic plasticity, to generating signal-to-noise contrast, defining temporal windows for integration and rate codes, as well as organizing neural assemblies, and coordinating inter-regional synchrony. GABAergic circuits are thus instrumental in controlling single-neuron computations and behaviorally-linked network activity. The activity dependent modulation of sensory and mnemonic information processing by GABAergic circuits is pivotal for the formation and maintenance of episodic memories in the hippocampus. Here, we present an overview of the local and long-range GABAergic circuits that modulate the dynamics of excitation-inhibition and disinhibition in the main output area of the hippocampus CA1, which is crucial for episodic memory. Specifically, we link recent findings pertaining to GABAergic neuron molecular markers, electrophysiological properties, and synaptic wiring with their function at the circuit level. Lastly, given that area CA1 is particularly impaired during early stages of Alzheimer's disease, we emphasize how these GABAergic circuits may contribute to and be involved in the pathophysiology.
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Affiliation(s)
- Melissa Hernández-Frausto
- Neuroscience Institute, New York University Langone Health, New York, NY, United States
- Department of Neuroscience and Physiology, New York University Grossman School of Medicine, New York, NY, United States
| | - Olesia M. Bilash
- Neuroscience Institute, New York University Langone Health, New York, NY, United States
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, United States
| | - Arjun V. Masurkar
- Neuroscience Institute, New York University Langone Health, New York, NY, United States
- Department of Neuroscience and Physiology, New York University Grossman School of Medicine, New York, NY, United States
- Center for Cognitive Neurology, Department of Neurology, New York University Grossman School of Medicine, New York, NY, United States
| | - Jayeeta Basu
- Neuroscience Institute, New York University Langone Health, New York, NY, United States
- Department of Neuroscience and Physiology, New York University Grossman School of Medicine, New York, NY, United States
- Department of Psychiatry, New York University Grossman School of Medicine, New York, NY, United States
- Center for Neural Science, New York University, New York, NY, United States
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13
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Dorman R, Bos JJ, Vinck MA, Marchesi P, Fiorilli J, Lorteije JAM, Reiten I, Bjaalie JG, Okun M, Pennartz CMA. Spike-based coupling between single neurons and populations across rat sensory cortices, perirhinal cortex, and hippocampus. Cereb Cortex 2023; 33:8247-8264. [PMID: 37118890 PMCID: PMC10425201 DOI: 10.1093/cercor/bhad111] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 03/09/2023] [Accepted: 03/10/2023] [Indexed: 04/30/2023] Open
Abstract
Cortical computations require coordination of neuronal activity within and across multiple areas. We characterized spiking relationships within and between areas by quantifying coupling of single neurons to population firing patterns. Single-neuron population coupling (SNPC) was investigated using ensemble recordings from hippocampal CA1 region and somatosensory, visual, and perirhinal cortices. Within-area coupling was heterogeneous across structures, with area CA1 showing higher levels than neocortical regions. In contrast to known anatomical connectivity, between-area coupling showed strong firing coherence of sensory neocortices with CA1, but less with perirhinal cortex. Cells in sensory neocortices and CA1 showed positive correlations between within- and between-area coupling; these were weaker for perirhinal cortex. All four areas harbored broadcasting cells, connecting to multiple external areas, which was uncorrelated to within-area coupling strength. When examining correlations between SNPC and spatial coding, we found that, if such correlations were significant, they were negative. This result was consistent with an overall preservation of SNPC across different brain states, suggesting a strong dependence on intrinsic network connectivity. Overall, SNPC offers an important window on cell-to-population synchronization in multi-area networks. Instead of pointing to specific information-coding functions, our results indicate a primary function of SNPC in dynamically organizing communication in systems composed of multiple, interconnected areas.
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Affiliation(s)
- Reinder Dorman
- Systems and Cognitive Neuroscience Group, SILS Center for Neuroscience, University of Amsterdam, 1098 XH Amsterdam, The Netherlands
| | - Jeroen J Bos
- Systems and Cognitive Neuroscience Group, SILS Center for Neuroscience, University of Amsterdam, 1098 XH Amsterdam, The Netherlands
- Donders Institute for Brain, Cognition and Behavior, Radboud University, 6500 HC Nijmegen, The Netherlands
| | - Martin A Vinck
- Systems and Cognitive Neuroscience Group, SILS Center for Neuroscience, University of Amsterdam, 1098 XH Amsterdam, The Netherlands
- Ernst Strüngmann Institute for Neuroscience in Cooperation with Max Plank Society, 60528 Frankfurt, Germany
| | - Pietro Marchesi
- Systems and Cognitive Neuroscience Group, SILS Center for Neuroscience, University of Amsterdam, 1098 XH Amsterdam, The Netherlands
| | - Julien Fiorilli
- Systems and Cognitive Neuroscience Group, SILS Center for Neuroscience, University of Amsterdam, 1098 XH Amsterdam, The Netherlands
| | - Jeanette A M Lorteije
- Systems and Cognitive Neuroscience Group, SILS Center for Neuroscience, University of Amsterdam, 1098 XH Amsterdam, The Netherlands
| | - Ingrid Reiten
- Institute of Basic Medical Sciences, University of Oslo, NO-0316 Oslo, Norway
| | - Jan G Bjaalie
- Institute of Basic Medical Sciences, University of Oslo, NO-0316 Oslo, Norway
| | - Michael Okun
- Department of Psychology and Neuroscience Institute, University of Sheffield, Sheffield S10 2TN, UK
| | - Cyriel M A Pennartz
- Systems and Cognitive Neuroscience Group, SILS Center for Neuroscience, University of Amsterdam, 1098 XH Amsterdam, The Netherlands
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14
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Wu Y, Chen ZS. Computational models for state-dependent traveling waves in hippocampal formation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.19.541436. [PMID: 37292865 PMCID: PMC10245836 DOI: 10.1101/2023.05.19.541436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Hippocampal theta (4-10 Hz) oscillations have been identified as traveling waves in both rodents and humans. In freely foraging rodents, the theta traveling wave is a planar wave propagating from the dorsal to ventral hippocampus along the septotemporal axis. Motivated from experimental findings, we develop a spiking neural network of excitatory and inhibitory neurons to generate state-dependent hippocampal traveling waves to improve current mechanistic understanding of propagating waves. Model simulations demonstrate the necessary conditions for generating wave propagation and characterize the traveling wave properties with respect to model parameters, running speed and brain state of the animal. Networks with long-range inhibitory connections are more suitable than networks with long-range excitatory connections. We further generalize the spiking neural network to model traveling waves in the medial entorhinal cortex (MEC) and predict that traveling theta waves in the hippocampus and entorhinal cortex are in sink.
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15
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Vancura B, Geiller T, Grosmark A, Zhao V, Losonczy A. Inhibitory control of sharp-wave ripple duration during learning in hippocampal recurrent networks. Nat Neurosci 2023; 26:788-797. [PMID: 37081295 PMCID: PMC10209669 DOI: 10.1038/s41593-023-01306-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 03/15/2023] [Indexed: 04/22/2023]
Abstract
Recurrent excitatory connections in hippocampal regions CA3 and CA2 are thought to play a key role in the generation of sharp-wave ripples (SWRs), electrophysiological oscillations tightly linked with learning and memory consolidation. However, it remains unknown how defined populations of inhibitory interneurons regulate these events during behavior. Here, we use large-scale, three-dimensional calcium imaging and retrospective molecular identification in the mouse hippocampus to characterize molecularly identified CA3 and CA2 interneuron activity during SWR-associated memory consolidation and spatial navigation. We describe subtype- and region-specific responses during behaviorally distinct brain states and find that SWRs are preceded by decreased cholecystokinin-expressing interneuron activity and followed by increased parvalbumin-expressing basket cell activity. The magnitude of these dynamics correlates with both SWR duration and behavior during hippocampal-dependent learning. Together these results assign subtype- and region-specific roles for inhibitory circuits in coordinating operations and learning-related plasticity in hippocampal recurrent circuits.
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Affiliation(s)
- Bert Vancura
- Department of Neuroscience, Columbia University, New York, NY, USA
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA
| | - Tristan Geiller
- Department of Neuroscience, Columbia University, New York, NY, USA.
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA.
| | - Andres Grosmark
- Department of Neuroscience, Columbia University, New York, NY, USA
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA
- University of Connecticut Medical School, Farmington, CT, USA
| | - Vivian Zhao
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA
| | - Attila Losonczy
- Department of Neuroscience, Columbia University, New York, NY, USA.
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA.
- The Kavli Institute for Brain Science, Columbia University, New York, NY, USA.
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16
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Chen YT, Arano R, Guo J, Saleem U, Li Y, Xu W. Inhibitory hippocampus-medial septum projection controls locomotion and exploratory behavior. Front Synaptic Neurosci 2023; 15:1042858. [PMID: 37091878 PMCID: PMC10116069 DOI: 10.3389/fnsyn.2023.1042858] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Accepted: 03/09/2023] [Indexed: 04/08/2023] Open
Abstract
Although the hippocampus is generally considered a cognitive center for spatial representation, learning, and memory, increasing evidence supports its roles in regulating locomotion. However, the neuronal mechanisms of the hippocampal regulation of locomotion and exploratory behavior remain unclear. In this study, we found that the inhibitory hippocampal synaptic projection to the medial septum (MS) bi-directionally controls the locomotor speed of mice. The activation of the MS-projecting interneurons in the hippocampus or the activation of the hippocampus-originated inhibitory synaptic terminals in the MS decreased locomotion and exploratory behavior. On the other hand, the inhibition of the hippocampus-originated inhibitory synaptic terminals in the MS increased locomotion. Unlike the septal projecting interneurons, the activation of the hippocampal interneurons projecting to the retrosplenial cortex did not change animal locomotion. Therefore, this study reveals a specific long-range inhibitory synaptic output from the hippocampus to the medial septum in the regulation of animal locomotion.
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Affiliation(s)
| | | | | | | | | | - Wei Xu
- Department of Neuroscience, The University of Texas Southwestern Medical Center, Dallas, TX, United States
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17
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Sysoeva MV, Kuznetsova GD, Sysoev IV, Ngomba RT, Vinogradova LV, Grishchenko AA, van Rijn CM, van Luijtelaar G. NETWORK ANALYSIS REVEALS A ROLE OF THE HIPPOCAMPUS IN ABSENCE SEIZURES: THE EFFECTS OF A CANNABINOID AGONIST. Epilepsy Res 2023; 192:107135. [PMID: 37023553 DOI: 10.1016/j.eplepsyres.2023.107135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 02/27/2023] [Accepted: 03/30/2023] [Indexed: 04/04/2023]
Abstract
The role of the hippocampus (Hp) in absence epileptic networks and the effect of endocannabinoid system on this network remain enigmatic. Here, using adapted nonlinear Granger causality, we compared the differences in network strength in four intervals (baseline or interictal, preictal, ictal and postictal) in two hours before (Epoch 1) and six hours (epochs 2, 3 and 4) after the administration of three different doses of the endocannabinoid agonist WIN55,212-2 (WIN) or solvent. Local field potentials were recorded for eight hours in 23 WAG/Rij rats in the Frontal (FC), Parietal PC), Occipital Cortex (OC) and in the hippocampus (Hp). The four intervals were visually marked by an expert neurophysiologist and the strength of couplings between electrode pairs were calculated in both directions. Ictally, a strong decrease in coupling strength was found between Hp and FC, as well as a large increase bidirectionally between PC and FC and unidirectionally from FC and PC to OC, and from FC to Hp over all epochs. The highest dose of WIN increased the couplings strength from FC to Hp and from OC to PC during 4 and 2 hr respectively in all intervals, and decreased the FC to PC coupling strength postictally in epoch 2. A single rat showed generalized convulsive seizures after the highest dose: this rat shared not only coupling changes with the other rats in the same condition, but showed many more. WIN reduced SWD number in epoch 2 and 3, their mean duration increased in epochs 3 and 4. Conclusions:during SWDs FC and PC are strongly coupled and drive OC, while at the same time the influence of Hp to FC is diminished. The first is in agreement with the cortical focus theory, the latter demonstrates an involvement of the hippocampus in SWD occurrence and that ictally the hippocampal control of the cortico-thalamo-cortical system is lost. WIN causes dramatic network changes which have major consequences for the decrease of SWDs, the occurrence of convulsive seizures, and the normal cortico-cortical and cortico-hippocampal interactions.
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18
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Ahmed N, Paré D. The Basolateral Amygdala Sends a Mixed (GABAergic and Glutamatergic) Projection to the Mediodorsal Thalamic Nucleus. J Neurosci 2023; 43:2104-2115. [PMID: 36788026 PMCID: PMC10039751 DOI: 10.1523/jneurosci.1924-22.2022] [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: 10/11/2022] [Revised: 12/13/2022] [Accepted: 12/20/2022] [Indexed: 02/16/2023] Open
Abstract
The medial prefrontal cortex receives converging inputs from the mediodorsal thalamic nucleus (MD) and basolateral amygdala (BLA). Although many studies reported that the BLA also projects to MD, there is conflicting evidence regarding this projection, with some data suggesting that it originates from GABAergic or glutamatergic neurons. Therefore, the present study aimed to determine the neurotransmitter used by MD-projecting BLA cells in male and female rats. We first examined whether BLA cells retrogradely labeled by Fast Blue infusions in MD are immunopositive for multiple established markers of BLA interneurons. A minority of MD-projecting BLA cells expressed somatostatin (∼22%) or calretinin (∼11%) but not other interneuronal markers, suggesting that BLA neurons projecting to MD not only include glutamatergic cells, but also long-range GABAergic neurons. Second, we examined the responses of MD cells to optogenetic activation of BLA axons using whole-cell recordings in vitro Consistent with our immunohistochemical findings, among responsive MD cells, light stimuli typically elicited isolated EPSPs (73%) or IPSPs (27%) as well as coincident EPSPs and IPSPs (11%). Indicating that these IPSPs were monosynaptic, light-evoked EPSPs and IPSPs had the same latency and the IPSPs persisted in the presence of ionotropic glutamate receptor antagonists. Overall, our results indicate that the BLA sends a mixed, glutamatergic-GABAergic projection to MD, which likely influences coordination of activity between BLA, MD, and medial prefrontal cortex. An important challenge for future studies will be to examine the connections formed by MD-projecting glutamatergic and GABAergic BLA cells with each other and other populations of BLA cells.SIGNIFICANCE STATEMENT The mediodorsal thalamic nucleus (MD) and basolateral amygdala (BLA) send convergent projections to the medial prefrontal cortex. Although many studies reported that the BLA also projects to MD, there is conflicting evidence as to whether this projection is glutamatergic or GABAergic. By combining tract tracing, immunohistochemistry, optogenetics, and patch clamp recordings in vitro, we found that BLA neurons projecting to MD not only include glutamatergic cells, but also long-range GABAergic neurons. Differential recruitment of these two contingents of cells likely influences coordination of activity between the BLA, MD, and medial prefrontal cortex.
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Affiliation(s)
- Nowrin Ahmed
- Center for Molecular and Behavioral Neuroscience, Rutgers University, Newark, New Jersey 07102
| | - Denis Paré
- Center for Molecular and Behavioral Neuroscience, Rutgers University, Newark, New Jersey 07102
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19
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Vancura B, Geiller T, Losonczy A. Organization and Plasticity of Inhibition in Hippocampal Recurrent Circuits. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.13.532296. [PMID: 36993553 PMCID: PMC10054977 DOI: 10.1101/2023.03.13.532296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Excitatory-inhibitory interactions structure recurrent network dynamics for efficient cortical computations. In the CA3 area of the hippocampus, recurrent circuit dynamics, including experience-induced plasticity at excitatory synapses, are thought to play a key role in episodic memory encoding and consolidation via rapid generation and flexible selection of neural ensembles. However, in vivo activity of identified inhibitory motifs supporting this recurrent circuitry has remained largely inaccessible, and it is unknown whether CA3 inhibition is also modifiable upon experience. Here we use large-scale, 3-dimensional calcium imaging and retrospective molecular identification in the mouse hippocampus to obtain the first comprehensive description of molecularly-identified CA3 interneuron dynamics during both spatial navigation and sharp-wave ripple (SWR)-associated memory consolidation. Our results uncover subtype-specific dynamics during behaviorally distinct brain-states. Our data also demonstrate predictive, reflective, and experience-driven plastic recruitment of specific inhibitory motifs during SWR-related memory reactivation. Together these results assign active roles for inhibitory circuits in coordinating operations and plasticity in hippocampal recurrent circuits.
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20
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Stieve BJ, Smith MM, Krook-Magnuson E. LINCs Are Vulnerable to Epileptic Insult and Fail to Provide Seizure Control via On-Demand Activation. eNeuro 2023; 10:ENEURO.0195-22.2022. [PMID: 36725340 PMCID: PMC9933934 DOI: 10.1523/eneuro.0195-22.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 12/13/2022] [Accepted: 12/19/2022] [Indexed: 02/03/2023] Open
Abstract
Temporal lobe epilepsy (TLE) is notoriously pharmacoresistant, and identifying novel therapeutic targets for controlling seizures is crucial. Long-range inhibitory neuronal nitric oxide synthase-expressing cells (LINCs), a population of hippocampal neurons, were recently identified as a unique source of widespread inhibition in CA1, able to elicit both GABAA-mediated and GABAB-mediated postsynaptic inhibition. We therefore hypothesized that LINCs could be an effective target for seizure control. LINCs were optogenetically activated for on-demand seizure intervention in the intrahippocampal kainate (KA) mouse model of chronic TLE. Unexpectedly, LINC activation at 1 month post-KA did not substantially reduce seizure duration in either male or female mice. We tested two different sets of stimulation parameters, both previously found to be effective with on-demand optogenetic approaches, but neither was successful. Quantification of LINCs following intervention revealed a substantial reduction of LINC numbers compared with saline-injected controls. We also observed a decreased number of LINCs when the site of initial insult (i.e., KA injection) was moved to the amygdala [basolateral amygdala (BLA)-KA], and correspondingly, no effect of light delivery on BLA-KA seizures. This indicates that LINCs may be a vulnerable population in TLE, regardless of the site of initial insult. To determine whether long-term circuitry changes could influence outcomes, we continued testing once a month for up to 6 months post-KA. However, at no time point did LINC activation provide meaningful seizure suppression. Altogether, our results suggest that LINCs are not a promising target for seizure inhibition in TLE.
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Affiliation(s)
- Bethany J Stieve
- Graduate Program in Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455
| | - Madison M Smith
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455
| | - Esther Krook-Magnuson
- Graduate Program in Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455
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21
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Karimi Abadchi J, Rezaei Z, Knöpfel T, McNaughton BL, Mohajerani MH. Inhibition is a prevalent mode of activity in the neocortex around awake hippocampal ripples in mice. eLife 2023; 12:79513. [PMID: 36645126 PMCID: PMC9876570 DOI: 10.7554/elife.79513] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 01/06/2023] [Indexed: 01/17/2023] Open
Abstract
Coordinated peri-ripple activity in the hippocampal-neocortical network is essential for mnemonic information processing in the brain. Hippocampal ripples likely serve different functions in sleep and awake states. Thus, the corresponding neocortical activity patterns may differ in important ways. We addressed this possibility by conducting voltage and glutamate wide-field imaging of the neocortex with concurrent hippocampal electrophysiology in awake mice. Contrary to our previously published sleep results, deactivation and activation were dominant in post-ripple neocortical voltage and glutamate activity, respectively, especially in the agranular retrosplenial cortex (aRSC). Additionally, the spiking activity of aRSC neurons, estimated by two-photon calcium imaging, revealed the existence of two subpopulations of excitatory neurons with opposite peri-ripple modulation patterns: one increases and the other decreases firing rate. These differences in peri-ripple spatiotemporal patterns of neocortical activity in sleep versus awake states might underlie the reported differences in the function of sleep versus awake ripples.
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Affiliation(s)
- Javad Karimi Abadchi
- Canadian Centre for Behavioral Neuroscience, University of LethbridgeLethbridgeCanada
| | - Zahra Rezaei
- Canadian Centre for Behavioral Neuroscience, University of LethbridgeLethbridgeCanada
| | - Thomas Knöpfel
- Laboratory for Neuronal Circuit Dynamics, Imperial College LondonLondonUnited Kingdom
- Department of Physics, Hong Kong Baptist UniversityKowloon TongHong Kong
| | - Bruce L McNaughton
- Canadian Centre for Behavioral Neuroscience, University of LethbridgeLethbridgeCanada
- Department of Neurobiology and Behavior, University of CaliforniaIrvineUnited States
| | - Majid H Mohajerani
- Canadian Centre for Behavioral Neuroscience, University of LethbridgeLethbridgeCanada
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22
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Mueller-Buehl C, Wegrzyn D, Bauch J, Faissner A. Regulation of the E/I-balance by the neural matrisome. Front Mol Neurosci 2023; 16:1102334. [PMID: 37143468 PMCID: PMC10151766 DOI: 10.3389/fnmol.2023.1102334] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 03/27/2023] [Indexed: 05/06/2023] Open
Abstract
In the mammalian cortex a proper excitatory/inhibitory (E/I) balance is fundamental for cognitive functions. Especially γ-aminobutyric acid (GABA)-releasing interneurons regulate the activity of excitatory projection neurons which form the second main class of neurons in the cortex. During development, the maturation of fast-spiking parvalbumin-expressing interneurons goes along with the formation of net-like structures covering their soma and proximal dendrites. These so-called perineuronal nets (PNNs) represent a specialized form of the extracellular matrix (ECM, also designated as matrisome) that stabilize structural synapses but prevent the formation of new connections. Consequently, PNNs are highly involved in the regulation of the synaptic balance. Previous studies revealed that the formation of perineuronal nets is accompanied by an establishment of mature neuronal circuits and by a closure of critical windows of synaptic plasticity. Furthermore, it has been shown that PNNs differentially impinge the integrity of excitatory and inhibitory synapses. In various neurological and neuropsychiatric disorders alterations of PNNs were described and aroused more attention in the last years. The following review gives an update about the role of PNNs for the maturation of parvalbumin-expressing interneurons and summarizes recent findings about the impact of PNNs in different neurological and neuropsychiatric disorders like schizophrenia or epilepsy. A targeted manipulation of PNNs might provide an interesting new possibility to indirectly modulate the synaptic balance and the E/I ratio in pathological conditions.
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Kołosowska KA, Schratt G, Winterer J. microRNA-dependent regulation of gene expression in GABAergic interneurons. Front Cell Neurosci 2023; 17:1188574. [PMID: 37213213 PMCID: PMC10196030 DOI: 10.3389/fncel.2023.1188574] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 04/20/2023] [Indexed: 05/23/2023] Open
Abstract
Information processing within neuronal circuits relies on their proper development and a balanced interplay between principal and local inhibitory interneurons within those circuits. Gamma-aminobutyric acid (GABA)ergic inhibitory interneurons are a remarkably heterogeneous population, comprising subclasses based on their morphological, electrophysiological, and molecular features, with differential connectivity and activity patterns. microRNA (miRNA)-dependent post-transcriptional control of gene expression represents an important regulatory mechanism for neuronal development and plasticity. miRNAs are a large group of small non-coding RNAs (21-24 nucleotides) acting as negative regulators of mRNA translation and stability. However, while miRNA-dependent gene regulation in principal neurons has been described heretofore in several studies, an understanding of the role of miRNAs in inhibitory interneurons is only beginning to emerge. Recent research demonstrated that miRNAs are differentially expressed in interneuron subclasses, are vitally important for migration, maturation, and survival of interneurons during embryonic development and are crucial for cognitive function and memory formation. In this review, we discuss recent progress in understanding miRNA-dependent regulation of gene expression in interneuron development and function. We aim to shed light onto mechanisms by which miRNAs in GABAergic interneurons contribute to sculpting neuronal circuits, and how their dysregulation may underlie the emergence of numerous neurodevelopmental and neuropsychiatric disorders.
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Affiliation(s)
| | - Gerhard Schratt
- Lab of Systems Neuroscience, Department of Health Science and Technology, Institute for Neuroscience, Swiss Federal Institute of Technology ETH, Zurich, Switzerland
| | - Jochen Winterer
- Lab of Systems Neuroscience, Department of Health Science and Technology, Institute for Neuroscience, Swiss Federal Institute of Technology ETH, Zurich, Switzerland
- *Correspondence: Jochen Winterer,
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Optogenetic Suppression of Lateral Septum Somatostatin Neurons Enhances Hippocampus Cholinergic Theta Oscillations and Local Synchrony. Brain Sci 2022; 13:brainsci13010001. [PMID: 36671983 PMCID: PMC9856160 DOI: 10.3390/brainsci13010001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2022] [Revised: 12/12/2022] [Accepted: 12/15/2022] [Indexed: 12/29/2022] Open
Abstract
The septal complex regulates both motivated and innate behaviors, chiefly by the action of its diverse population of long-range projection neurons. A small population of somatostatin-expressing GABAergic cells in the lateral septum projects deep into subcortical regions, yet on its way it also targets neighboring medial septum neurons that profusely innervate cortical targets by ascending synaptic pathways. Here, we used optogenetic stimulation and extracellular recordings in acutely anesthetized transgenic mice to show that lateral septum somatostatin neurons can disinhibit the cholinergic septo-hippocampal pathway, thus enhancing the amplitude and synchrony of theta oscillations while depressing sharp-wave ripple episodes in the dorsal hippocampus. These results suggest that septal somatostatin cells can recruit ascending cholinergic pathways to promote hippocampal theta oscillations.
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25
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Oligodendroglia are emerging players in several forms of learning and memory. Commun Biol 2022; 5:1148. [PMID: 36309567 PMCID: PMC9617857 DOI: 10.1038/s42003-022-04116-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 10/14/2022] [Indexed: 11/15/2022] Open
Abstract
Synaptic plasticity is the fundamental cellular mechanism of learning and memory, but recent research reveals that myelin-forming glia, oligodendrocytes (OL), are also involved. They contribute in ways that synaptic plasticity cannot, and the findings have not been integrated into the established conceptual framework used in the field of learning and memory. OLs and their progenitors are involved in long-term memory, memory consolidation, working memory, and recall in associative learning. They also contribute to short-term memory and non-associative learning by affecting synaptic transmission, intrinsic excitability of axons, and neural oscillations. Oligodendroglial involvement expands the field beyond synaptic plasticity to system-wide network function, where precise spike time arrival and neural oscillations are critical in information processing, storage, and retrieval. A Perspective highlights current evidence that supports oligodendrocytes and their progenitors’ involvement in cognition and proposes that our understanding of learning and memory can be expanded beyond the classic view of synaptic plasticity to a system-wide network function.
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26
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Li H, Sung HH, Lau CG. Activation of Somatostatin-Expressing Neurons in the Lateral Septum Improves Stress-Induced Depressive-like Behaviors in Mice. Pharmaceutics 2022; 14:pharmaceutics14102253. [PMID: 36297687 PMCID: PMC9607457 DOI: 10.3390/pharmaceutics14102253] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 10/15/2022] [Accepted: 10/19/2022] [Indexed: 11/17/2022] Open
Abstract
Depression is a debilitating mood disorder with highly heterogeneous pathogenesis. The limbic system is well-linked to depression. As an important node in the limbic system, the lateral septum (LS) can modulate multiple affective and motivational behaviors. However, the role of LS in depression remains unclear. By using c-Fos expression mapping, we first screened and showed activation of the LS in various depression-related behavioral tests, including the forced swim test (FST), tail suspension test (TST), and sucrose preference test. In the LS, more than 10% of the activated neurons were somatostatin-expressing (SST) neurons. We next developed a microendoscopic calcium imaging method in freely moving mice and revealed that LSSST neural activity increased during mobility in the TST but not open field test. We hypothesize that LSSST neuronal activity is linked to stress and depression. In two mouse models of depression, repeated lipopolysaccharide (LPS) injection and chronic restraint stress (CRS), we showed that LS neuronal activation was suppressed. To examine whether the re-activation of LSSST neurons can be therapeutically beneficial, we optogenetically activated LSSST neurons and produced antidepressant-like effects in LPS-injected mice by increasing TST motility. Moreover, chemogenetic activation of LSSST neurons increased FST struggling in the CRS-exposed mice. Together, these results provide the first evidence of a role for LSSST neurons in regulating depressive-like behaviors in mice and identify them as a potential therapeutic target for neuromodulation-based intervention in depression.
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Affiliation(s)
- Huanhuan Li
- Department of Neuroscience, City University of Hong Kong, Hong Kong 999077, China
- Shenzhen Research Institute, City University of Hong Kong, Shenzhen 518057, China
| | - Hyun Hailey Sung
- Department of Neuroscience, City University of Hong Kong, Hong Kong 999077, China
- Shenzhen Research Institute, City University of Hong Kong, Shenzhen 518057, China
| | - Chunyue Geoffrey Lau
- Department of Neuroscience, City University of Hong Kong, Hong Kong 999077, China
- Shenzhen Research Institute, City University of Hong Kong, Shenzhen 518057, China
- Correspondence: ; Tel.: +852-3442-4345
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27
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Basu K, Appukuttan S, Manchanda R, Sik A. Difference in axon diameter and myelin thickness between excitatory and inhibitory callosally projecting axons in mice. Cereb Cortex 2022; 33:4101-4115. [PMID: 36205478 PMCID: PMC10068302 DOI: 10.1093/cercor/bhac329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 07/18/2022] [Accepted: 08/02/2022] [Indexed: 11/13/2022] Open
Abstract
Synchronization of network oscillation in spatially distant cortical areas is essential for normal brain activity. Precision in synchronization between hemispheres depends on the axonal conduction velocity, which is determined by physical parameters of the axons involved, including diameter, and extent of myelination. To compare these parameters in long-projecting excitatory and inhibitory axons in the corpus callosum, we used genetically modified mice and virus tracing to separately label CaMKIIα expressing excitatory and GABAergic inhibitory axons. Using electron microscopy analysis, we revealed that (i) the axon diameters of excitatory fibers (myelinated axons) are significantly larger than those of nonmyelinated excitatory axons; (ii) the diameters of bare axons of excitatory myelinated fibers are significantly larger than those of their inhibitory counterparts; and (iii) myelinated excitatory fibers are significantly larger than myelinated inhibitory fibers. Also, the thickness of myelin ensheathing inhibitory axons is significantly greater than for excitatory axons, with the ultrastructure of the myelin around excitatory and inhibitory fibers also differing. We generated a computational model to investigate the functional consequences of these parameter divergences. Our simulations indicate that impulses through inhibitory and excitatory myelinated fibers reach the target almost simultaneously, whereas action potentials conducted by nonmyelinated axons reach target cells with considerable delay.
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Affiliation(s)
- Kaustuv Basu
- Facility for Electron Microscopy Research, McGill University, Montreal, QC H3A 0C72, Canada.,Department of Anatomy & Cell Biology, McGill University, Montreal, Canada
| | - Shailesh Appukuttan
- Biomedical Engineering Group, Department of Biosciences & Bioengineering IIT Bombay, Powai, Mumbay, 4000764, India
| | - Rohit Manchanda
- Biomedical Engineering Group, Department of Biosciences & Bioengineering IIT Bombay, Powai, Mumbay, 4000764, India
| | - Attila Sik
- College of Medical and Dental Sciences, University of Birmingham, Vincent Drive, Birmingham B15 2TT, United Kingdom.,Institute of Physiology, Medical School, University of Pecs, Pecs H-7624, Hungary.,Institute of Transdisciplinary Discoveries, Medical School, University of Pecs, Pecs H-7624, Hungary
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28
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Curot J, Barbeau E, Despouy E, Denuelle M, Sol JC, Lotterie JA, Valton L, Peyrache A. Local neuronal excitation and global inhibition during epileptic fast ripples in humans. Brain 2022; 146:561-575. [PMID: 36093747 PMCID: PMC9924905 DOI: 10.1093/brain/awac319] [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: 02/09/2022] [Revised: 07/01/2022] [Accepted: 08/01/2022] [Indexed: 11/12/2022] Open
Abstract
Understanding the neuronal basis of epileptic activity is a major challenge in neurology. Cellular integration into larger scale networks is all the more challenging. In the local field potential, interictal epileptic discharges can be associated with fast ripples (200-600 Hz), which are a promising marker of the epileptogenic zone. Yet, how neuronal populations in the epileptogenic zone and in healthy tissue are affected by fast ripples remain unclear. Here, we used a novel 'hybrid' macro-micro depth electrode in nine drug-resistant epileptic patients, combining classic depth recording of local field potentials (macro-contacts) and two or three tetrodes (four micro-wires bundled together) enabling up to 15 neurons in local circuits to be simultaneously recorded. We characterized neuronal responses (190 single units) with the timing of fast ripples (2233 fast ripples) on the same hybrid and other electrodes that target other brain regions. Micro-wire recordings reveal signals that are not visible on macro-contacts. While fast ripples detected on the closest macro-contact to the tetrodes were always associated with fast ripples on the tetrodes, 82% of fast ripples detected on tetrodes were associated with detectable fast ripples on the nearest macro-contact. Moreover, neuronal recordings were taken in and outside the epileptogenic zone of implanted epileptic subjects and they revealed an interlay of excitation and inhibition across anatomical scales. While fast ripples were associated with increased neuronal activity in very local circuits only, they were followed by inhibition in large-scale networks (beyond the epileptogenic zone, even in healthy cortex). Neuronal responses to fast ripples were homogeneous in local networks but differed across brain areas. Similarly, post-fast ripple inhibition varied across recording locations and subjects and was shorter than typical inter-fast ripple intervals, suggesting that this inhibition is a fundamental refractory process for the networks. These findings demonstrate that fast ripples engage local and global networks, including healthy tissue, and point to network features that pave the way for new diagnostic and therapeutic strategies. They also reveal how even localized pathological brain dynamics can affect a broad range of cognitive functions.
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Affiliation(s)
- Jonathan Curot
- Correspondence to: Jonathan Curot, MD, PhD CerCo CNRS UMR 5549, Université Toulouse III CHU Purpan, Pavillon Baudot, 31052 Toulouse Cedex, France E-mail:
| | - Emmanuel Barbeau
- Brain and Cognition Research Center (CerCo), Centre National de la Recherche Scientifique, UMR5549, Toulouse, France,Faculty of Health, University of Toulouse, Paul Sabatier University, Toulouse, France
| | - Elodie Despouy
- Brain and Cognition Research Center (CerCo), Centre National de la Recherche Scientifique, UMR5549, Toulouse, France
| | - Marie Denuelle
- Departments of Neurology and Neurosurgery, Toulouse University Hospital, Toulouse, France,Brain and Cognition Research Center (CerCo), Centre National de la Recherche Scientifique, UMR5549, Toulouse, France
| | - Jean Christophe Sol
- Departments of Neurology and Neurosurgery, Toulouse University Hospital, Toulouse, France,Faculty of Health, University of Toulouse, Paul Sabatier University, Toulouse, France,Toulouse Neuro Imaging Center (ToNIC), INSERM, U1214, Toulouse, France
| | - Jean-Albert Lotterie
- Departments of Neurology and Neurosurgery, Toulouse University Hospital, Toulouse, France,Toulouse Neuro Imaging Center (ToNIC), INSERM, U1214, Toulouse, France
| | - Luc Valton
- Departments of Neurology and Neurosurgery, Toulouse University Hospital, Toulouse, France,Brain and Cognition Research Center (CerCo), Centre National de la Recherche Scientifique, UMR5549, Toulouse, France
| | - Adrien Peyrache
- Correspondence may also be addressed to: Adrien Peyrache, PhD Montreal Neurological Institute Department of Neurology and Neurosurgery McGill University, 3810 University Street Montreal, Quebec, Canada E-mail:
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29
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The role of inhibitory circuits in hippocampal memory processing. Nat Rev Neurosci 2022; 23:476-492. [DOI: 10.1038/s41583-022-00599-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/22/2022] [Indexed: 11/08/2022]
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30
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Yen TY, Huang X, MacLaren DAA, Schlesiger MI, Monyer H, Lien CC. Inhibitory projections connecting the dentate gyri in the two hemispheres support spatial and contextual memory. Cell Rep 2022; 39:110831. [PMID: 35584671 DOI: 10.1016/j.celrep.2022.110831] [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: 11/12/2020] [Revised: 11/17/2021] [Accepted: 04/27/2022] [Indexed: 12/01/2022] Open
Abstract
The dentate gyrus (DG) receives substantial input from the homologous brain area of the contralateral hemisphere. This input is by and large excitatory. Viral-tracing experiments provided anatomical evidence for the existence of GABAergic connectivity between the two DGs, but the function of these projections has remained elusive. Combining electrophysiological and optogenetic approaches, we demonstrate that somatostatin-expressing contralateral DG (SOM+ cDG)-projecting neurons preferentially engage dendrite-targeting interneurons over principal neurons. Single-unit recordings from freely moving mice reveal that optogenetic stimulation of SOM+ cDG projections modulates the activity of GABAergic neurons and principal neurons over multiple timescales. Importantly, we demonstrate that optogenetic silencing of SOM+ cDG projections during spatial memory encoding, but not during memory retrieval, results in compromised DG-dependent memory. Moreover, optogenetic stimulation of SOM+ cDG projections is sufficient to disrupt contextual memory recall. Collectively, our findings reveal that SOM+ long-range projections mediate inter-DG inhibition and contribute to learning and memory.
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Affiliation(s)
- Ting-Yun Yen
- Taiwan International Graduate Program in Molecular Medicine, National Yang Ming Chiao Tung University and Academia Sinica, Taipei, Taiwan; Institute of Neuroscience, National Yang Ming Chiao Tung University, Taipei 112, Taiwan; Department of Clinical Neurobiology at the Medical Faculty of Heidelberg University and German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Xu Huang
- Department of Clinical Neurobiology at the Medical Faculty of Heidelberg University and German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Duncan Archibald Allan MacLaren
- Department of Clinical Neurobiology at the Medical Faculty of Heidelberg University and German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Magdalene Isabell Schlesiger
- Department of Clinical Neurobiology at the Medical Faculty of Heidelberg University and German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Hannah Monyer
- Department of Clinical Neurobiology at the Medical Faculty of Heidelberg University and German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany.
| | - Cheng-Chang Lien
- Taiwan International Graduate Program in Molecular Medicine, National Yang Ming Chiao Tung University and Academia Sinica, Taipei, Taiwan; Institute of Neuroscience, National Yang Ming Chiao Tung University, Taipei 112, Taiwan.
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31
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Subcortical control of the default mode network: Role of the basal forebrain and implications for neuropsychiatric disorders. Brain Res Bull 2022; 185:129-139. [PMID: 35562013 PMCID: PMC9290753 DOI: 10.1016/j.brainresbull.2022.05.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 04/29/2022] [Accepted: 05/04/2022] [Indexed: 01/03/2023]
Abstract
The precise interplay between large-scale functional neural systems throughout the brain is essential for performance of cognitive processes. In this review we focus on the default mode network (DMN), one such functional network that is active during periods of quiet wakefulness and believed to be involved in introspection and planning. Abnormalities in DMN functional connectivity and activation appear across many neuropsychiatric disorders, including schizophrenia. Recent evidence suggests subcortical regions including the basal forebrain are functionally and structurally important for regulation of DMN activity. Within the basal forebrain, subregions like the ventral pallidum may influence DMN activity and the nucleus basalis of Meynert can inhibit switching between brain networks. Interactions between DMN and other functional networks including the medial frontoparietal network (default), lateral frontoparietal network (control), midcingulo-insular network (salience), and dorsal frontoparietal network (attention) are also discussed in the context of neuropsychiatric disorders. Several subtypes of basal forebrain neurons have been identified including basal forebrain parvalbumin-containing or somatostatin-containing neurons which can regulate cortical gamma band oscillations and DMN-like behaviors, and basal forebrain cholinergic neurons which might gate access to sensory information during reinforcement learning. In this review, we explore this evidence, discuss the clinical implications on neuropsychiatric disorders, and compare neuroanatomy in the human vs rodent DMN. Finally, we address technological advancements which could help provide a more complete understanding of modulation of DMN function and describe newly identified BF therapeutic targets that could potentially help restore DMN-associated functional deficits in patients with a variety of neuropsychiatric disorders.
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32
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Malik R, Li Y, Schamiloglu S, Sohal VS. Top-down control of hippocampal signal-to-noise by prefrontal long-range inhibition. Cell 2022; 185:1602-1617.e17. [PMID: 35487191 PMCID: PMC10027400 DOI: 10.1016/j.cell.2022.04.001] [Citation(s) in RCA: 46] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 11/15/2021] [Accepted: 03/31/2022] [Indexed: 02/07/2023]
Abstract
Prefrontal cortex (PFC) is postulated to exert "top-down control" on information processing throughout the brain to promote specific behaviors. However, pathways mediating top-down control remain poorly understood. In particular, knowledge about direct prefrontal connections that might facilitate top-down control of hippocampal information processing remains sparse. Here we describe monosynaptic long-range GABAergic projections from PFC to hippocampus. These preferentially inhibit vasoactive intestinal polypeptide-expressing interneurons, which are known to disinhibit hippocampal microcircuits. Indeed, stimulating prefrontal-hippocampal GABAergic projections increases hippocampal feedforward inhibition and reduces hippocampal activity in vivo. The net effect of these actions is to specifically enhance the signal-to-noise ratio for hippocampal encoding of object locations and augment object-induced increases in spatial information. Correspondingly, activating or inhibiting these projections promotes or suppresses object exploration, respectively. Together, these results elucidate a top-down prefrontal pathway in which long-range GABAergic projections target disinhibitory microcircuits, thereby enhancing signals and network dynamics underlying exploratory behavior.
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Affiliation(s)
- Ruchi Malik
- Department of Psychiatry and Behavioral Sciences, UCSF Weill Institute for Neurosciences, Kavli Institute for Fundamental Neuroscience, University of California San Francisco, San Francisco, CA, USA
| | - Yi Li
- Department of Psychiatry and Behavioral Sciences, UCSF Weill Institute for Neurosciences, Kavli Institute for Fundamental Neuroscience, University of California San Francisco, San Francisco, CA, USA
| | - Selin Schamiloglu
- Department of Psychiatry and Behavioral Sciences, UCSF Weill Institute for Neurosciences, Kavli Institute for Fundamental Neuroscience, University of California San Francisco, San Francisco, CA, USA
| | - Vikaas S Sohal
- Department of Psychiatry and Behavioral Sciences, UCSF Weill Institute for Neurosciences, Kavli Institute for Fundamental Neuroscience, University of California San Francisco, San Francisco, CA, USA.
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Szabo GG, Farrell JS, Dudok B, Hou WH, Ortiz AL, Varga C, Moolchand P, Gulsever CI, Gschwind T, Dimidschstein J, Capogna M, Soltesz I. Ripple-selective GABAergic projection cells in the hippocampus. Neuron 2022; 110:1959-1977.e9. [PMID: 35489331 DOI: 10.1016/j.neuron.2022.04.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 02/10/2022] [Accepted: 04/04/2022] [Indexed: 10/18/2022]
Abstract
Ripples are brief high-frequency electrographic events with important roles in episodic memory. However, the in vivo circuit mechanisms coordinating ripple-related activity among local and distant neuronal ensembles are not well understood. Here, we define key characteristics of a long-distance projecting GABAergic cell group in the mouse hippocampus that selectively exhibits high-frequency firing during ripples while staying largely silent during theta-associated states when most other GABAergic cells are active. The high ripple-associated firing commenced before ripple onset and reached its maximum before ripple peak, with the signature theta-OFF, ripple-ON firing pattern being preserved across awake and sleep states. Controlled by septal GABAergic, cholinergic, and CA3 glutamatergic inputs, these ripple-selective cells innervate parvalbumin and cholecystokinin-expressing local interneurons while also targeting a variety of extra-hippocampal regions. These results demonstrate the existence of a hippocampal GABAergic circuit element that is uniquely positioned to coordinate ripple-related neuronal dynamics across neuronal assemblies.
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Affiliation(s)
- Gergely G Szabo
- Department of Neurosurgery, Stanford University, Stanford, CA, USA.
| | - Jordan S Farrell
- Department of Neurosurgery, Stanford University, Stanford, CA, USA
| | - Barna Dudok
- Department of Neurosurgery, Stanford University, Stanford, CA, USA
| | - Wen-Hsien Hou
- Department of Biomedicine, Aarhus University, Aarhus, Denmark; DANDRITE, The Danish Research Institute of Translational Neuroscience, Aarhus University, Aarhus, Denmark
| | - Anna L Ortiz
- Department of Neurosurgery, Stanford University, Stanford, CA, USA
| | - Csaba Varga
- Department of Neurosurgery, Stanford University, Stanford, CA, USA
| | | | | | - Tilo Gschwind
- Department of Neurosurgery, Stanford University, Stanford, CA, USA
| | - Jordane Dimidschstein
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Marco Capogna
- Department of Biomedicine, Aarhus University, Aarhus, Denmark; DANDRITE, The Danish Research Institute of Translational Neuroscience, Aarhus University, Aarhus, Denmark; Center for Proteins in Memory - PROMEMO, Danish National Research Foundation, Aarhus University, Aarhus, Denmark
| | - Ivan Soltesz
- Department of Neurosurgery, Stanford University, Stanford, CA, USA
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Urrutia-Piñones J, Morales-Moraga C, Sanguinetti-González N, Escobar AP, Chiu CQ. Long-Range GABAergic Projections of Cortical Origin in Brain Function. Front Syst Neurosci 2022; 16:841869. [PMID: 35392440 PMCID: PMC8981584 DOI: 10.3389/fnsys.2022.841869] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 02/10/2022] [Indexed: 12/12/2022] Open
Abstract
The study of long-range GABAergic projections has traditionally been focused on those with subcortical origin. In the last few years, cortical GABAergic neurons have been shown to not only mediate local inhibition, but also extend long-range axons to remote cortical and subcortical areas. In this review, we delineate the different types of long-range GABAergic neurons (LRGNs) that have been reported to arise from the hippocampus and neocortex, paying attention to the anatomical and functional circuits they form to understand their role in behavior. Although cortical LRGNs are similar to their interneuron and subcortical counterparts, they comprise distinct populations that show specific patterns of cortico-cortical and cortico-fugal connectivity. Functionally, cortical LRGNs likely induce timed disinhibition in target regions to synchronize network activity. Thus, LRGNs are emerging as a new element of cortical output, acting in concert with long-range excitatory projections to shape brain function in health and disease.
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Affiliation(s)
- Jocelyn Urrutia-Piñones
- Ph.D. Program in Neuroscience, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
- Facultad de Ciencias, Instituto de Neurociencia, Universidad de Valparaíso, Valparaíso, Chile
| | - Camila Morales-Moraga
- Facultad de Ciencias, Instituto de Neurociencia, Universidad de Valparaíso, Valparaíso, Chile
- Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
| | - Nicole Sanguinetti-González
- Ph.D. Program in Neuroscience, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
- Facultad de Ciencias, Instituto de Neurociencia, Universidad de Valparaíso, Valparaíso, Chile
| | - Angelica P. Escobar
- Instituto de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
- Centro de Neurobiología y Fisiopatología Integrativa, Universidad de Valparaíso, Valparaíso, Chile
| | - Chiayu Q. Chiu
- Facultad de Ciencias, Instituto de Neurociencia, Universidad de Valparaíso, Valparaíso, Chile
- Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
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Mikroulis A, Ledri M, Ruffolo G, Palma E, Sperk G, Dalli J, Vezzani A, Kokaia M. Lipid mediator n-3 docosapentaenoic acid-derived protectin D1 enhances synaptic inhibition of hippocampal principal neurons by interaction with a G-protein-coupled receptor. FASEB J 2022; 36:e22203. [PMID: 35188290 PMCID: PMC9306510 DOI: 10.1096/fj.202101815r] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 01/27/2022] [Accepted: 01/31/2022] [Indexed: 01/16/2023]
Abstract
Epilepsy is a severe neurological disease manifested by spontaneous recurrent seizures due to abnormal hyper‐synchronization of neuronal activity. Epilepsy affects about 1% of the population and up to 40% of patients experience seizures that are resistant to currently available drugs, thus highlighting an urgent need for novel treatments. In this regard, anti‐inflammatory drugs emerged as potential therapeutic candidates. In particular, specific molecules apt to resolve the neuroinflammatory response occurring in acquired epilepsies have been proven to counteract seizures in experimental models, and humans. One candidate investigational molecule has been recently identified as the lipid mediator n‐3 docosapentaenoic acid‐derived protectin D1 (PD1n‐3DPA) which significantly reduced seizures, cell loss, and cognitive deficit in a mouse model of acquired epilepsy. However, the mechanisms that mediate the PD1n‐3DPA effect remain elusive. We here addressed whether PD1n‐3DPA has direct effects on neuronal activity independent of its anti‐inflammatory action. We incubated, therefore, hippocampal slices with PD1n‐3DPA and investigated its effect on excitatory and inhibitory synaptic inputs to the CA1 pyramidal neurons. We demonstrate that inhibitory drive onto the perisomatic region of the pyramidal neurons is increased by PD1n‐3DPA, and this effect is mediated by pertussis toxin‐sensitive G‐protein coupled receptors. Our data indicate that PD1n‐3DPA acts directly on inhibitory transmission, most likely at the presynaptic site of inhibitory synapses as also supported by Xenopus oocytes and immunohistochemical experiments. Thus, in addition to its anti‐inflammatory effects, PD1n‐3DPA anti‐seizure and neuroprotective effects may be mediated by its direct action on neuronal excitability by modulating their synaptic inputs.
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Affiliation(s)
- Apostolos Mikroulis
- Epilepsy Center, Department of Clinical Sciences, Faculty of Medicine, Lund University, Lund, Sweden
| | - Marco Ledri
- Epilepsy Center, Department of Clinical Sciences, Faculty of Medicine, Lund University, Lund, Sweden
| | - Gabriele Ruffolo
- Department of Physiology and Pharmacology, Istituto Pasteur-Fondazione Cenci Bolognetti, University of Rome Sapienza, Rome, Italy.,IRCCS San Raffaele Pisana, Rome, Italy
| | - Eleonora Palma
- Department of Physiology and Pharmacology, Istituto Pasteur-Fondazione Cenci Bolognetti, University of Rome Sapienza, Rome, Italy
| | - Günther Sperk
- Department of Pharmacology, Medical University Innsbruck, Innsbruck, Austria
| | - Jesmond Dalli
- William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK.,Centre for Inflammation and Therapeutic Innovation, Queen Mary University of London, London, UK
| | - Annamaria Vezzani
- Mario Negri Institute for Pharmacological Research IRCCS, Milan, Italy
| | - Merab Kokaia
- Epilepsy Center, Department of Clinical Sciences, Faculty of Medicine, Lund University, Lund, Sweden
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36
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Fernandez AM, Gutekunst CA, Grogan DP, Pedersen NP, Gross RE. Loss of efferent projections of the hippocampal formation in the mouse intrahippocampal kainic acid model. Epilepsy Res 2022; 180:106863. [PMID: 35114430 DOI: 10.1016/j.eplepsyres.2022.106863] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 12/15/2021] [Accepted: 01/17/2022] [Indexed: 11/16/2022]
Abstract
Unilateral intrahippocampal injection of kainic acid is used as a model of medial temporal lobe epilepsy and provides a platform to study the mechanisms of epilepsy. Here, we used an AAV-9 EYFP-tagged viral vector as an anterograde tracer, injected into the dorsal and ventral hippocampus after kainic acid injection, to map out the efferent hippocampal projections after the development of spontaneous seizures in this model. The purpose of the study was to identify the extent of changes in hippocampal efferent system in several brain regions that receive significant inputs from the hippocampus. Loss of efferent hippocampal fibers was greatest in the retrosplenial cortex where neuronal loss was also observed. Loss of fibers was also observed in the fornix without any specific effect in the lateral mammillary nuclei. Although expected, these observations provide further evidence of the broader network effects as a result of hippocampal cell loss.
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Affiliation(s)
- Alejandra M Fernandez
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Claire-Anne Gutekunst
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, GA, 30322, USA.
| | - Dayton P Grogan
- Department of Neurosurgery, Augusta University Hospital, Augusta, GA, 30912, USA
| | - Nigel P Pedersen
- Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, 30332, USA; Department of Neurology, Emory University, Atlanta, GA, 30322, USA
| | - Robert E Gross
- Department of Neurosurgery, Emory University School of Medicine, Atlanta, GA, 30322, USA; Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, 30332, USA; Department of Neurology, Emory University, Atlanta, GA, 30322, USA.
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37
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Lomi E, Mathiasen ML, Cheng HY, Zhang N, Aggleton JP, Mitchell AS, Jeffery KJ. Evidence for two distinct thalamocortical circuits in retrosplenial cortex. Neurobiol Learn Mem 2021; 185:107525. [PMID: 34555510 DOI: 10.1016/j.nlm.2021.107525] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 08/20/2021] [Accepted: 09/15/2021] [Indexed: 01/04/2023]
Abstract
Retrosplenial cortex (RSC) lies at the interface between sensory and cognitive networks in the brain and mediates between these, although it is not yet known how. It has two distinct subregions, granular (gRSC) and dysgranular (dRSC). The present study investigated how these subregions differ with respect to their electrophysiology and thalamic connectivity, as a step towards understanding their functions. The gRSC is more closely connected to the hippocampal formation, in which theta-band local field potential oscillations are prominent. We, therefore, compared theta-rhythmic single-unit activity between the two RSC subregions and found, mostly in gRSC, a subpopulation of non-directional cells with spiking activity strongly entrained by theta oscillations, suggesting a stronger coupling of gRSC to the hippocampal system. We then used retrograde tracers to test for differential inputs to RSC from the anteroventral thalamus (AV). We found that gRSC and dRSC differ in their afferents from two AV subfields: dorsomedial (AVDM) and ventrolateral (AVVL). Specifically: (1) as a whole AV projects more strongly to gRSC; (2) AVVL targets both gRSC and dRSC, while AVDM provides a selective projection to gRSC, (3) the gRSC projection is layer-specific: AVDM targets specifically gRSC superficial layers. These same AV projections are topographically organized with ventral AV neurons innervating rostral RSC and dorsal AV neurons innervating caudal RSC. These combined results suggest the existence of two distinct but interacting RSC subcircuits: one connecting AVDM to gRSC that may comprise part of the cognitive hippocampal system, and the other connecting AVVL to both RSC regions that may link hippocampal and perceptual regions. We suggest that these subcircuits are distinct to allow for differential weighting during integration of converging sensory and cognitive computations: an integration that may take place in thalamus, RSC, or both.
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Affiliation(s)
- Eleonora Lomi
- Department of Experimental Psychology, University of Oxford, The Tinsley Building, Mansfield Road, Oxford OX1 3SR, UK.
| | | | - Han Y Cheng
- Department of Psychological and Brain Sciences, Dartmouth College, Hanover, New Hampshire, USA
| | - Ningyu Zhang
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China
| | | | - Anna S Mitchell
- Department of Experimental Psychology, University of Oxford, The Tinsley Building, Mansfield Road, Oxford OX1 3SR, UK
| | - Kate J Jeffery
- Institute of Behavioural Neuroscience, Division of Psychology and Language Sciences, University College London, London WC1E 6BT, UK
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38
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Gala D, Gurusamy V, Patel K, Damodar S, Swaminath G, Ullal G. Stem Cell Therapy for Post-Traumatic Stress Disorder: A Novel Therapeutic Approach. Diseases 2021; 9:diseases9040077. [PMID: 34842629 PMCID: PMC8628773 DOI: 10.3390/diseases9040077] [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: 08/19/2021] [Revised: 10/11/2021] [Accepted: 10/25/2021] [Indexed: 12/04/2022] Open
Abstract
Stem cell therapy is a rapidly evolving field of regenerative medicine being employed for the management of various central nervous system disorders. The ability to self-renew, differentiate into specialized cells, and integrate into neuronal networks has positioned stem cells as an ideal mechanism for the treatment of epilepsy. Epilepsy is characterized by repetitive seizures caused by imbalance in the GABA and glutamate neurotransmission following neuronal damage. Stem cells provide benefit by reducing the glutamate excitotoxicity and strengthening the GABAergic inter-neuron connections. Similar to the abnormal neuroanatomic location in epilepsy, post-traumatic stress disorder (PTSD) is caused by hyperarousal in the amygdala and decreased activity of the hippocampus and medial prefrontal cortex. Thus, stem cells could be used to modulate neuronal interconnectivity. In this review, we provide a rationale for the use of stem cell therapy in the treatment of PTSD.
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39
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Denovellis EL, Gillespie AK, Coulter ME, Sosa M, Chung JE, Eden UT, Frank LM. Hippocampal replay of experience at real-world speeds. eLife 2021; 10:64505. [PMID: 34570699 PMCID: PMC8476125 DOI: 10.7554/elife.64505] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 09/08/2021] [Indexed: 01/12/2023] Open
Abstract
Representations related to past experiences play a critical role in memory and decision-making processes. The rat hippocampus expresses these types of representations during sharp-wave ripple (SWR) events, and previous work identified a minority of SWRs that contain ‘replay’ of spatial trajectories at ∼20x the movement speed of the animal. Efforts to understand replay typically make multiple assumptions about which events to examine and what sorts of representations constitute replay. We therefore lack a clear understanding of both the prevalence and the range of representational dynamics associated with replay. Here, we develop a state space model that uses a combination of movement dynamics of different speeds to capture the spatial content and time evolution of replay during SWRs. Using this model, we find that the large majority of replay events contain spatially coherent, interpretable content. Furthermore, many events progress at real-world, rather than accelerated, movement speeds, consistent with actual experiences.
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Affiliation(s)
- Eric L Denovellis
- Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, United States.,Departments of Physiology and Psychiatry, University of California, San Francisco, San Francisco, United States.,Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, United States
| | - Anna K Gillespie
- Departments of Physiology and Psychiatry, University of California, San Francisco, San Francisco, United States.,Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, United States
| | - Michael E Coulter
- Departments of Physiology and Psychiatry, University of California, San Francisco, San Francisco, United States.,Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, United States
| | - Marielena Sosa
- Department of Neurobiology, Stanford University School of Medicine, Stanford, United States
| | - Jason E Chung
- Department of Neurological Surgery, University of California, San Francisco, San Francisco, United States
| | - Uri T Eden
- Department of Mathematics and Statistics, Boston University, Boston, United States
| | - Loren M Frank
- Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, United States.,Departments of Physiology and Psychiatry, University of California, San Francisco, San Francisco, United States.,Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, United States
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40
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Zacharopoulos G, Sella F, Emir U, Cohen Kadosh R. The relation between parietal GABA concentration and numerical skills. Sci Rep 2021; 11:17656. [PMID: 34480033 PMCID: PMC8417296 DOI: 10.1038/s41598-021-95370-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Accepted: 05/12/2021] [Indexed: 11/21/2022] Open
Abstract
Several scientific, engineering, and medical advancements are based on breakthroughs made by people who excel in mathematics. Our current understanding of the underlying brain networks stems primarily from anatomical and functional investigations, but our knowledge of how neurotransmitters subserve numerical skills, the building block of mathematics, is scarce. Using 1H magnetic resonance spectroscopy (N = 54, 3T, semi-LASER sequence, TE = 32 ms, TR = 3.5 s), the study examined the relation between numerical skills and the brain's major inhibitory (GABA) and excitatory (glutamate) neurotransmitters. A negative association was found between the performance in a number sequences task and the resting concentration of GABA within the left intraparietal sulcus (IPS), a key region supporting numeracy. The relation between GABA in the IPS and number sequences was specific to (1) parietal but not frontal regions and to (2) GABA but not glutamate. It was additionally found that the resting functional connectivity of the left IPS and the left superior frontal gyrus was positively associated with number sequences performance. However, resting GABA concentration within the IPS explained number sequences performance above and beyond the resting frontoparietal connectivity measure. Our findings further motivate the study of inhibition mechanisms in the human brain and significantly contribute to our current understanding of numerical cognition's biological bases.
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Affiliation(s)
- George Zacharopoulos
- Department of Experimental Psychology, Wellcome Centre for Integrative Neuroimaging, University of Oxford, Oxford, UK.
- Department of Psychology, Swansea University, Swansea, UK.
| | - Francesco Sella
- Centre for Mathematical Cognition, Loughborough University, Loughborough, UK
| | - Uzay Emir
- School of Health Sciences, College of Health and Human Sciences, Purdue University, West Lafayette, IN, 47907-2051, USA
| | - Roi Cohen Kadosh
- Department of Experimental Psychology, Wellcome Centre for Integrative Neuroimaging, University of Oxford, Oxford, UK.
- School of Psychology, University of Surrey, Guildford, UK.
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41
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Development, Diversity, and Death of MGE-Derived Cortical Interneurons. Int J Mol Sci 2021; 22:ijms22179297. [PMID: 34502208 PMCID: PMC8430628 DOI: 10.3390/ijms22179297] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 08/24/2021] [Accepted: 08/25/2021] [Indexed: 12/17/2022] Open
Abstract
In the mammalian brain, cortical interneurons (INs) are a highly diverse group of cells. A key neurophysiological question concerns how each class of INs contributes to cortical circuit function and whether specific roles can be attributed to a selective cell type. To address this question, researchers are integrating knowledge derived from transcriptomic, histological, electrophysiological, developmental, and functional experiments to extensively characterise the different classes of INs. Our hope is that such knowledge permits the selective targeting of cell types for therapeutic endeavours. This review will focus on two of the main types of INs, namely the parvalbumin (PV+) or somatostatin (SOM+)-containing cells, and summarise the research to date on these classes.
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42
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Takeuchi Y, Nagy AJ, Barcsai L, Li Q, Ohsawa M, Mizuseki K, Berényi A. The Medial Septum as a Potential Target for Treating Brain Disorders Associated With Oscillopathies. Front Neural Circuits 2021; 15:701080. [PMID: 34305537 PMCID: PMC8297467 DOI: 10.3389/fncir.2021.701080] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 06/14/2021] [Indexed: 12/14/2022] Open
Abstract
The medial septum (MS), as part of the basal forebrain, supports many physiological functions, from sensorimotor integration to cognition. With often reciprocal connections with a broad set of peers at all major divisions of the brain, the MS orchestrates oscillatory neuronal activities throughout the brain. These oscillations are critical in generating sensory and emotional salience, locomotion, maintaining mood, supporting innate anxiety, and governing learning and memory. Accumulating evidence points out that the physiological oscillations under septal influence are frequently disrupted or altered in pathological conditions. Therefore, the MS may be a potential target for treating neurological and psychiatric disorders with abnormal oscillations (oscillopathies) to restore healthy patterns or erase undesired ones. Recent studies have revealed that the patterned stimulation of the MS alleviates symptoms of epilepsy. We discuss here that stimulus timing is a critical determinant of treatment efficacy on multiple time scales. On-demand stimulation may dramatically reduce side effects by not interfering with normal physiological functions. A precise pattern-matched stimulation through adaptive timing governed by the ongoing oscillations is essential to effectively terminate pathological oscillations. The time-targeted strategy for the MS stimulation may provide an effective way of treating multiple disorders including Alzheimer's disease, anxiety/fear, schizophrenia, and depression, as well as pain.
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Affiliation(s)
- Yuichi Takeuchi
- Department of Physiology, Osaka City University Graduate School of Medicine, Osaka, Japan
| | - Anett J. Nagy
- MTA-SZTE ‘Momentum’ Oscillatory Neuronal Networks Research Group, Department of Physiology, University of Szeged, Szeged, Hungary
| | - Lívia Barcsai
- MTA-SZTE ‘Momentum’ Oscillatory Neuronal Networks Research Group, Department of Physiology, University of Szeged, Szeged, Hungary
| | - Qun Li
- MTA-SZTE ‘Momentum’ Oscillatory Neuronal Networks Research Group, Department of Physiology, University of Szeged, Szeged, Hungary
| | - Masahiro Ohsawa
- Department of Neuropharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan
| | - Kenji Mizuseki
- Department of Physiology, Osaka City University Graduate School of Medicine, Osaka, Japan
| | - Antal Berényi
- MTA-SZTE ‘Momentum’ Oscillatory Neuronal Networks Research Group, Department of Physiology, University of Szeged, Szeged, Hungary
- Neurocybernetics Excellence Center, University of Szeged, Szeged, Hungary
- HCEMM-USZ Magnetotherapeutics Research Group, University of Szeged, Szeged, Hungary
- Neuroscience Institute, New York University, New York, NY, United States
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43
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Hippocampus-retrosplenial cortex interaction is increased during phasic REM and contributes to memory consolidation. Sci Rep 2021; 11:13078. [PMID: 34158548 PMCID: PMC8219679 DOI: 10.1038/s41598-021-91659-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 05/20/2021] [Indexed: 11/23/2022] Open
Abstract
Hippocampal (HPC) theta oscillation during post-training rapid eye movement (REM) sleep supports spatial learning. Theta also modulates neuronal and oscillatory activity in the retrosplenial cortex (RSC) during REM sleep. To investigate the relevance of theta-driven interaction between these two regions to memory consolidation, we computed the Granger causality within theta range on electrophysiological data recorded in freely behaving rats during REM sleep, both before and after contextual fear conditioning. We found a training-induced modulation of causality between HPC and RSC that was correlated with memory retrieval 24 h later. Retrieval was proportional to the change in the relative influence RSC exerted upon HPC theta oscillation. Importantly, causality peaked during theta acceleration, in synchrony with phasic REM sleep. Altogether, these results support a role for phasic REM sleep in hippocampo-cortical memory consolidation and suggest that causality modulation between RSC and HPC during REM sleep plays a functional role in that phenomenon.
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44
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Hristova K, Martinez-Gonzalez C, Watson TC, Codadu NK, Hashemi K, Kind PC, Nolan MF, Gonzalez-Sulser A. Medial septal GABAergic neurons reduce seizure duration upon optogenetic closed-loop stimulation. Brain 2021; 144:1576-1589. [PMID: 33769452 PMCID: PMC8219369 DOI: 10.1093/brain/awab042] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 11/16/2020] [Accepted: 12/06/2020] [Indexed: 11/22/2022] Open
Abstract
Seizures can emerge from multiple or large foci in temporal lobe epilepsy, complicating focally targeted strategies such as surgical resection or the modulation of the activity of specific hippocampal neuronal populations through genetic or optogenetic techniques. Here, we evaluate a strategy in which optogenetic activation of medial septal GABAergic neurons, which provide extensive projections throughout the hippocampus, is used to control seizures. We utilized the chronic intrahippocampal kainate mouse model of temporal lobe epilepsy, which results in spontaneous seizures and as is often the case in human patients, presents with hippocampal sclerosis. Medial septal GABAergic neuron populations were immunohistochemically labelled and were not reduced in epileptic conditions. Genetic labelling with mRuby of medial septal GABAergic neuron synaptic puncta and imaging across the rostral to caudal extent of the hippocampus, also indicated an unchanged number of putative synapses in epilepsy. Furthermore, optogenetic stimulation of medial septal GABAergic neurons consistently modulated oscillations across multiple hippocampal locations in control and epileptic conditions. Finally, wireless optogenetic stimulation of medial septal GABAergic neurons, upon electrographic detection of spontaneous hippocampal seizures, resulted in reduced seizure durations. We propose medial septal GABAergic neurons as a novel target for optogenetic control of seizures in temporal lobe epilepsy.
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Affiliation(s)
- Katerina Hristova
- Centre for Discovery Brain Sciences, Simons Initiative for the Developing
Brain, Patrick Wild Centre, University of Edinburgh, Edinburgh, UK
- Simons Initiative for the Developing Brain and Patrick Wild Centre, University
of Edinburgh, Edinburgh, UK
| | - Cristina Martinez-Gonzalez
- Centre for Discovery Brain Sciences, Simons Initiative for the Developing
Brain, Patrick Wild Centre, University of Edinburgh, Edinburgh, UK
- Simons Initiative for the Developing Brain and Patrick Wild Centre, University
of Edinburgh, Edinburgh, UK
| | - Thomas C Watson
- Centre for Discovery Brain Sciences, Simons Initiative for the Developing
Brain, Patrick Wild Centre, University of Edinburgh, Edinburgh, UK
- Simons Initiative for the Developing Brain and Patrick Wild Centre, University
of Edinburgh, Edinburgh, UK
| | - Neela K Codadu
- Centre for Discovery Brain Sciences, Simons Initiative for the Developing
Brain, Patrick Wild Centre, University of Edinburgh, Edinburgh, UK
- Simons Initiative for the Developing Brain and Patrick Wild Centre, University
of Edinburgh, Edinburgh, UK
| | | | - Peter C Kind
- Centre for Discovery Brain Sciences, Simons Initiative for the Developing
Brain, Patrick Wild Centre, University of Edinburgh, Edinburgh, UK
- Simons Initiative for the Developing Brain and Patrick Wild Centre, University
of Edinburgh, Edinburgh, UK
| | - Matthew F Nolan
- Centre for Discovery Brain Sciences, Simons Initiative for the Developing
Brain, Patrick Wild Centre, University of Edinburgh, Edinburgh, UK
- Simons Initiative for the Developing Brain and Patrick Wild Centre, University
of Edinburgh, Edinburgh, UK
| | - Alfredo Gonzalez-Sulser
- Centre for Discovery Brain Sciences, Simons Initiative for the Developing
Brain, Patrick Wild Centre, University of Edinburgh, Edinburgh, UK
- Simons Initiative for the Developing Brain and Patrick Wild Centre, University
of Edinburgh, Edinburgh, UK
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45
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Zacharopoulos G, Emir U, Cohen Kadosh R. The cross-sectional interplay between neurochemical profile and brain connectivity. Hum Brain Mapp 2021; 42:2722-2733. [PMID: 33835605 PMCID: PMC8127145 DOI: 10.1002/hbm.25396] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 02/11/2021] [Accepted: 02/21/2021] [Indexed: 01/05/2023] Open
Abstract
Neurochemical profile and brain connectivity are both critical aspects of brain function. However, our knowledge of their interplay across development is currently poor. We combined single-voxel magnetic resonance spectroscopy and resting functional magnetic resonance imaging in a cross-sectional sample spanning from childhood to adulthood which was reassessed in ~1.5 years (N = 293). We revealed the developmental trajectories of 20 neurochemicals in two key developmental brain regions (the intraparietal sulcus, IPS, and the middle frontal gyrus, MFG). We found that certain neurochemicals exhibited similar developmental trajectories across the two regions, while other trajectories were region-specific. Crucially, we mapped the connectivity of the brain regions IPS and MFG to the rest of the brain across development as a function of regional glutamate and GABA concentration. We demonstrated that glutamate concentration within the IPS is modulated by age in explaining IPS connectivity with frontal, temporal and parietal regions. In mature participants, higher glutamate within the IPS was related to more negative connectivity while the opposite pattern was found for younger participants. Our findings offer specific developmental insights on the interplay between the brain's resting activity and the glutamatergic system both of which are crucial for regulating normal functioning and are dysregulated in several clinical conditions.
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Affiliation(s)
- George Zacharopoulos
- Wellcome Centre for Integrative Neuroimaging, Department of Experimental PsychologyUniversity of OxfordOxfordUK
| | - Uzay Emir
- Wellcome Centre for Integrative Neuroimaging, Department of Experimental PsychologyUniversity of OxfordOxfordUK
- School of Health Sciences, College of Health and Human SciencesPurdue UniversityWest LafayetteIndianaUSA
| | - Roi Cohen Kadosh
- Wellcome Centre for Integrative Neuroimaging, Department of Experimental PsychologyUniversity of OxfordOxfordUK
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46
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Hájos N. Interneuron Types and Their Circuits in the Basolateral Amygdala. Front Neural Circuits 2021; 15:687257. [PMID: 34177472 PMCID: PMC8222668 DOI: 10.3389/fncir.2021.687257] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 05/11/2021] [Indexed: 11/29/2022] Open
Abstract
The basolateral amygdala (BLA) is a cortical structure based on its cell types, connectivity features, and developmental characteristics. This part of the amygdala is considered to be the main entry site of processed and multisensory information delivered via cortical and thalamic afferents. Although GABAergic inhibitory cells in the BLA comprise only 20% of the entire neuronal population, they provide essential control over proper network operation. Previous studies have uncovered that GABAergic cells in the basolateral amygdala are as diverse as those present in other cortical regions, including the hippocampus and neocortex. To understand the role of inhibitory cells in various amygdala functions, we need to reveal the connectivity and input-output features of the different types of GABAergic cells. Here, I review the recent achievements in uncovering the diversity of GABAergic cells in the basolateral amygdala with a specific focus on the microcircuit organization of these inhibitory cells.
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Affiliation(s)
- Norbert Hájos
- Laboratory of Network Neurophysiology, ELRN Institute of Experimental Medicine, Budapest, Hungary
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47
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Honoré E, Khlaifia A, Bosson A, Lacaille JC. Hippocampal Somatostatin Interneurons, Long-Term Synaptic Plasticity and Memory. Front Neural Circuits 2021; 15:687558. [PMID: 34149368 PMCID: PMC8206813 DOI: 10.3389/fncir.2021.687558] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 04/30/2021] [Indexed: 12/13/2022] Open
Abstract
A distinctive feature of the hippocampal structure is the diversity of inhibitory interneurons. These complex inhibitory interconnections largely contribute to the tight modulation of hippocampal circuitry, as well as to the formation and coordination of neuronal assemblies underlying learning and memory. Inhibitory interneurons provide more than a simple transitory inhibition of hippocampal principal cells (PCs). The synaptic plasticity of inhibitory neurons provides long-lasting changes in the hippocampal network and is a key component of memory formation. The dendrite targeting interneurons expressing the peptide somatostatin (SOM) are particularly interesting in this regard because they display unique long-lasting synaptic changes leading to metaplastic regulation of hippocampal networks. In this article, we examine the actions of the neuropeptide SOM on hippocampal cells, synaptic plasticity, learning, and memory. We address the different subtypes of hippocampal SOM interneurons. We describe the long-term synaptic plasticity that takes place at the excitatory synapses of SOM interneurons, its singular induction and expression mechanisms, as well as the consequences of these changes on the hippocampal network, learning, and memory. We also review evidence that astrocytes provide cell-specific dynamic regulation of inhibition of PC dendrites by SOM interneurons. Finally, we cover how, in mouse models of Alzheimer’s disease (AD), dysfunction of plasticity of SOM interneuron excitatory synapses may also contribute to cognitive impairments in brain disorders.
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Affiliation(s)
- Eve Honoré
- Department of Neurosciences, Centre for Interdisciplinary Research on Brain and Learning, Research Group on the Central Nervous System, Université de Montréal, Montreal, QC, Canada
| | - Abdessattar Khlaifia
- Department of Neurosciences, Centre for Interdisciplinary Research on Brain and Learning, Research Group on the Central Nervous System, Université de Montréal, Montreal, QC, Canada
| | - Anthony Bosson
- Department of Neurosciences, Centre for Interdisciplinary Research on Brain and Learning, Research Group on the Central Nervous System, Université de Montréal, Montreal, QC, Canada
| | - Jean-Claude Lacaille
- Department of Neurosciences, Centre for Interdisciplinary Research on Brain and Learning, Research Group on the Central Nervous System, Université de Montréal, Montreal, QC, Canada
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Mazuir E, Richevaux L, Nassar M, Robil N, de la Grange P, Lubetzki C, Fricker D, Sol-Foulon N. Oligodendrocyte Secreted Factors Shape Hippocampal GABAergic Neuron Transcriptome and Physiology. Cereb Cortex 2021; 31:5024-5041. [PMID: 34023893 DOI: 10.1093/cercor/bhab139] [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: 11/10/2020] [Revised: 03/26/2021] [Accepted: 04/17/2021] [Indexed: 11/14/2022] Open
Abstract
Oligodendrocytes form myelin for central nervous system axons and release factors which signal to neurons during myelination. Here, we ask how oligodendroglial factors influence hippocampal GABAergic neuron physiology. In mixed hippocampal cultures, GABAergic neurons fired action potentials (APs) of short duration and received high frequencies of excitatory synaptic events. In purified neuronal cultures without glial cells, GABAergic neuron excitability increased and the frequency of synaptic events decreased. These effects were largely reversed by adding oligodendrocyte conditioned medium (OCM). We compared the transcriptomic signature with the electrophysiological phenotype of single neurons in these three culture conditions. Genes expressed by single pyramidal or GABAergic neurons largely conformed to expected cell-type specific patterns. Multiple genes of GABAergic neurons were significantly downregulated by the transition from mixed cultures containing glial cells to purified neuronal cultures. Levels of these genes were restored by the addition of OCM to purified cultures. Clustering genes with similar changes in expression between different culture conditions revealed processes affected by oligodendroglial factors. Enriched genes are linked to roles in synapse assembly, AP generation, and transmembrane ion transport, including of zinc. These results provide new insight into the molecular targets by which oligodendrocytes influence neuron excitability and synaptic function.
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Affiliation(s)
- Elisa Mazuir
- Sorbonne University, Inserm, CNRS, Paris Brain Institute, ICM, Pitié-Salpêtrière Hospital, F-75013 Paris, France
| | | | - Merie Nassar
- Université de Paris, INCC UMR 8002, CNRS, F-75006 Paris
| | | | | | - Catherine Lubetzki
- Sorbonne University, Inserm, CNRS, Paris Brain Institute, ICM, Pitié-Salpêtrière Hospital, F-75013 Paris, France.,Assistance Publique des Hôpitaux de Paris (APHP), Neurology Department, Pitié-Salpêtrière hospital, Paris 75013, France
| | | | - Nathalie Sol-Foulon
- Sorbonne University, Inserm, CNRS, Paris Brain Institute, ICM, Pitié-Salpêtrière Hospital, F-75013 Paris, France
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49
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Vetere G, Xia F, Ramsaran AI, Tran LM, Josselyn SA, Frankland PW. An inhibitory hippocampal-thalamic pathway modulates remote memory retrieval. Nat Neurosci 2021; 24:685-693. [PMID: 33782621 PMCID: PMC8715645 DOI: 10.1038/s41593-021-00819-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 02/18/2021] [Indexed: 01/30/2023]
Abstract
Memories are supported by distributed hippocampal-thalamic-cortical networks, but the brain regions that contribute to network activity may vary with memory age. This process of reorganization is referred to as systems consolidation, and previous studies have examined the relationship between the activation of different hippocampal, thalamic, and cortical brain regions and memory age at the time of recall. While the activation of some brain regions increases with memory age, other regions become less active. In mice, here we show that the active disengagement of one such brain region, the anterodorsal thalamic nucleus, is necessary for recall at remote time-points and, in addition, which projection(s) mediate such inhibition. Specifically, we identified a sparse inhibitory projection from CA3 to the anterodorsal thalamic nucleus that becomes more active during systems consolidation, such that it is necessary for contextual fear memory retrieval at remote, but not recent, time-points post-learning.
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Affiliation(s)
- Gisella Vetere
- Program in Neurosciences & Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada,Team Cerebral Codes and Circuits Connectivity (C4), Plasticité du Cerveau, ESPCI Paris, CNRS, PSL University, Paris, France,These authors contributed equally: Gisella Vetere, Frances Xia
| | - Frances Xia
- Program in Neurosciences & Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada,Department of Physiology, University of Toronto, Toronto, Ontario, Canada,These authors contributed equally: Gisella Vetere, Frances Xia
| | - Adam I. Ramsaran
- Program in Neurosciences & Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada,Department of Psychology, University of Toronto, Toronto, Ontario, Canada
| | - Lina M. Tran
- Program in Neurosciences & Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada,Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Sheena A. Josselyn
- Program in Neurosciences & Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada,Department of Physiology, University of Toronto, Toronto, Ontario, Canada,Department of Psychology, University of Toronto, Toronto, Ontario, Canada,Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada,Brain, Mind & Consciousness Program, Canadian Institute for Advanced Research, Toronto, Ontario, Canada
| | - Paul W. Frankland
- Program in Neurosciences & Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada,Department of Physiology, University of Toronto, Toronto, Ontario, Canada,Department of Psychology, University of Toronto, Toronto, Ontario, Canada,Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada,Child & Brain Development Program, Canadian Institute for Advanced Research, Toronto, Ontario, Canada,Correspondence and requests for materials should be addressed to P.W.F.
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50
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Damborsky JC, Yakel JL. Regulation of hippocamposeptal input within the medial septum/diagonal band of Broca. Neuropharmacology 2021; 191:108589. [PMID: 33933476 DOI: 10.1016/j.neuropharm.2021.108589] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 04/21/2021] [Accepted: 04/25/2021] [Indexed: 11/19/2022]
Abstract
The medial septum/diagonal band of Broca (MS/DBB) receives direct GABAergic input from the hippocampus via hippocamposeptal (HS) projection neurons as part of a reciprocal loop that mediates cognition and is altered in Alzheimer's disease. Cholinergic and GABAergic interactions occur throughout the MS/DBB, but it is not known how HS GABA release is impacted by these circuits. Most HS neurons contain somatostatin (SST), so to evoke HS GABA release we expressed Cre-dependent mCherry/channelrhodopisin-2 (ChR2) in the hippocampi of SST-IRES-Cre mice and then used optogenetics to stimulate HS fibers while performing whole-cell patch clamp recordings from MS/DBB neurons in acute slices. We found that the acetylcholine receptor (AChR) agonist carbachol and the GABAB receptor (GABABR) agonist baclofen significantly decreased HS GABA release in the MS/DBB. Carbachol's effects were blocked by eliminating local GABAergic activity or inhibiting GABABRs, indicating that it was indirectly decreasing HS GABA release by increasing GABAergic tone. There was no effect of acute exposure to amyloid-β on HS GABA release. Repetitive stimulation of HS fibers increased spontaneous GABA release in the MS/DBB, revealing that HS projections can modulate local GABAergic tone. These results show that HS GABA release has far-reaching impacts on overall levels of inhibition in the MS/DBB and is under regulatory control by cholinergic and GABAergic activity. This bidirectional modulation of GABA release from local and HS projections in the MS/DBB will likely have profound impact not only on activity within the MS/DBB, but also on output to the hippocampus and hippocampal-dependent learning and memory.
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Affiliation(s)
- Joanne C Damborsky
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 TW Alexander Dr., Research Triangle Park, NC, 27709, USA
| | - Jerrel L Yakel
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 TW Alexander Dr., Research Triangle Park, NC, 27709, USA.
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