1
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Aracava Y, Albuquerque EX, Pereira EFR. (R,S)-trihexyphenidyl, acting via a muscarinic receptor-independent mechanism, inhibits hippocampal glutamatergic and GABAergic synaptic transmissions: Potential relevance for treatment of organophosphorus intoxication. Neuropharmacology 2023; 239:109684. [PMID: 37549771 PMCID: PMC10590273 DOI: 10.1016/j.neuropharm.2023.109684] [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: 03/11/2023] [Revised: 08/03/2023] [Accepted: 08/04/2023] [Indexed: 08/09/2023]
Abstract
Preclinical studies have reported that, compared to the muscarinic receptor (mAChR) antagonist atropine, (R,S)-trihexyphenidyl (THP) more effectively counters the cholinergic crisis, seizures, and neuropathology triggered by organophosphorus (OP)-induced acetylcholinesterase (AChE) inhibition. The greater effectiveness of THP was attributed to its ability to block mAChRs and N-methyl-d-aspartate-type glutamatergic receptors (NMDARs) in the brain. However, THP also inhibits α7 nicotinic receptors (nAChRs). The present study examined whether THP-induced inhibition of mAChRs, α7 nAChRs, and NMDARs is required to suppress glutamatergic synaptic transmission, whose overstimulation sustains OP-induced seizures. In primary hippocampal cultures, THP (1-30 μM) suppressed the frequency of excitatory and inhibitory postsynaptic currents (EPSCs and IPSCs, respectively) recorded from neurons in nominally Mg2+-free solution. A single sigmoidal function adequately fit the overlapping concentration-response relationships for THP-induced suppression of IPSC and EPSC frequencies yielding an IC50 of 6.3 ± 1.3 μM. Atropine (1 μM), the NMDAR antagonist d,l-2-amino-5-phosphonopentanoic acid (D,L-AP5, 50 μM), and the α7 nAChR antagonist methyllycaconitine (MLA, 10 nM) did not prevent THP-induced inhibition of synaptic transmission. THP (10 μM) did not affect the probability of transmitter release because it had no effect on the frequency of miniature IPSCs and EPSCs recorded in the presence of tetrodotoxin. Additionally, THP had no effect on the amplitudes and decay-time constants of miniature IPSCs and EPSCs; therefore, it did not affect the activity of postsynaptic GABAA and glutamate receptors. This study provides the first demonstration that THP can suppress action potential-dependent synaptic transmission via a mechanism independent of NMDAR, mAChR, and α7 nAChR inhibition.
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Affiliation(s)
- Yasco Aracava
- Division of Translational Toxicology, Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Edson X Albuquerque
- Division of Translational Toxicology, Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Edna F R Pereira
- Division of Translational Toxicology, Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, MD, USA.
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2
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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: 1] [Impact Index Per Article: 1.0] [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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3
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Qi C, Li Y, Gu H, Yang Y. Nonlinear mechanism for the enhanced bursting activities induced by fast inhibitory autapse and reduced activities by fast excitatory autapse. Cogn Neurodyn 2023; 17:1093-1113. [PMID: 37522049 PMCID: PMC10374520 DOI: 10.1007/s11571-022-09872-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 07/28/2022] [Accepted: 08/13/2022] [Indexed: 08/01/2023] Open
Abstract
The paradoxical phenomena that excitatory modulation does not enhance but reduces or inhibitory modulation not suppresses but promotes neural firing activities have attracted increasing attention. In the present study, paradoxical phenomena induced by both fast excitatory and inhibitory autapses in a "Fold/Big Homoclinic" bursting are simulated, and the corresponding nonlinear and biophysical mechanisms are presented. Firstly, the enhanced conductance of excitatory autapse induces the number of spikes per burst and firing rate reduced, while the enhanced inhibitory autapse cause both indicators increased. Secondly, with fast-slow variable dissection, the burst of bursting is identified to locate between a fold bifurcation and a big saddle-homoclinic orbit bifurcation of the fast subsystem. Enhanced excitatory or inhibitory autapses cannot induce changes of both bifurcation points, i.e., burst width. However, width of slow variable between two successive spikes within a burst becomes wider for the excitatory autapse and narrower for the inhibitory autapse, resulting in the less and more spikes per burst, respectively. Last, the autaptic current of fast autapse mainly plays a role during the peak of action potential, differing from the slow autaptic current with exponential decay, which can play roles following the peak of action potential. The fast excitatory autaptic current enhances the amplitude of the action potential and reduces the repolarization of the action potential to lengthen the interspike interval (ISI) of the spiking of the fast subsystem, resulting in the wide width of slow variable between successive spikes. The fast inhibitory autaptic current reduces the amplitude of action potential and ISI of spiking, resulting in narrow width of slow variable. The novel example of the paradoxical responses for both fast modulations and nonlinear mechanism extend the contents of neurodynamics, which presents potential functions of the fast autapse.
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Affiliation(s)
- Changsheng Qi
- College of Chemistry and Life Sciences, Chifeng University, Chifeng, 024000 China
| | - Yuye Li
- College of Mathematics and Computer Science, Chifeng University, Chifeng, 024000 China
| | - Huaguang Gu
- School of Aerospace Engineering and Applied Mechanics, Tongji University, Shanghai, 200092 China
| | - Yongxia Yang
- College of Mathematics and Computer Science, Chifeng University, Chifeng, 024000 China
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4
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Cao B, Scherrer G, Chen L. Spinal cord retinoic acid receptor signaling gates mechanical hypersensitivity in neuropathic pain. Neuron 2022; 110:4108-4124.e6. [PMID: 36223767 PMCID: PMC9789181 DOI: 10.1016/j.neuron.2022.09.027] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 08/27/2022] [Accepted: 09/22/2022] [Indexed: 02/08/2023]
Abstract
Central sensitization caused by spinal disinhibition is a key mechanism of mechanical allodynia in neuropathic pain. However, the molecular mechanisms underlying spinal disinhibition after nerve injury remain unclear. Here, we show in mice that spared nerve injury (SNI), which induces mechanical hypersensitivity and neuropathic pain, triggers homeostatic reduction of inhibitory outputs from dorsal horn parvalbumin-positive (PV+) interneurons onto both primary afferent terminals and excitatory interneurons. The reduction in inhibitory outputs drives hyperactivation of the spinal cord nociceptive pathway, causing mechanical hypersensitivity. We identified the retinoic acid receptor RARα, a central regulator of homeostatic plasticity, as the key molecular mediator for this synaptic disinhibition. Deletion of RARα in spinal PV+ neurons or application of an RARα antagonist in the spinal cord prevented the development of SNI-induced mechanical hypersensitivity. Our results identify RARα as a crucial molecular effector for neuropathic pain and a potential target for its treatment.
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Affiliation(s)
- Bing Cao
- Department of Neurosurgery, Wu Tsai Neuroscience Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Gregory Scherrer
- Department of Cell Biology and Physiology, UNC Neuroscience Center, Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Lu Chen
- Department of Neurosurgery, Wu Tsai Neuroscience Institute, Stanford University School of Medicine, Stanford, CA 94305, USA.
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5
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The mGlu 7 receptor in schizophrenia - An update and future perspectives. Pharmacol Biochem Behav 2022; 218:173430. [PMID: 35870668 DOI: 10.1016/j.pbb.2022.173430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2022] [Revised: 07/07/2022] [Accepted: 07/11/2022] [Indexed: 11/21/2022]
Abstract
The mGlu7 receptor belongs to the III group of metabotropic glutamatergic (mGlu) receptors and physiologically serves as an "emergency" receptor that is activated by high, almost pathological, glutamate concentrations. Of all mGlu receptors, this receptor is most highly expressed in the brain. Additionally, relatively intense expression of the receptor was found at the periphery, for example in the bowels or in the reproductive system of male mice, but this review will be focused predominantly on its role in the brain. In the CNS, the receptor is expressed presynaptically, in the center of the synaptic cleft, at the terminals of both excitatory glutamatergic and inhibitory GABAergic neurons. Thus, it may regulate the release of both glutamate and GABA. Schizophrenia is thought to develop as a consequence of a disturbed glutamatergic-GABAergic balance in different parts of the brain. Thus, the mGlu7 receptor may be involved in the pathophysiology of schizophrenia and consequently constitute the target for antipsychotic drug discovery. In this review, we summarize the available data about mGlu7 receptor ligands and their activity in animal models of schizophrenia. At present, only a few ligands are available, and negative allosteric modulators (NAMs) appear to exert antipsychotic-like efficacy, indicating that the inhibition of the receptor could constitute a promising target in the search for novel drugs. Additionally, the data concerning the expression of the receptor in the CNS and putative mechanisms by which its inhibition may contribute to the treatment of schizophrenia will be discussed. Finally, the polymorphisms of genes encoding the receptor in schizophrenic patients will also be provided.
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6
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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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7
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Juarez P, Martínez Cerdeño V. Parvalbumin and parvalbumin chandelier interneurons in autism and other psychiatric disorders. Front Psychiatry 2022; 13:913550. [PMID: 36311505 PMCID: PMC9597886 DOI: 10.3389/fpsyt.2022.913550] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 09/22/2022] [Indexed: 11/13/2022] Open
Abstract
Parvalbumin (PV) is a calcium binding protein expressed by inhibitory fast-spiking interneurons in the cerebral cortex. By generating a fast stream of action potentials, PV+ interneurons provide a quick and stable inhibitory input to pyramidal neurons and contribute to the generation of gamma oscillations in the cortex. Their fast-firing rates, while advantageous for regulating cortical signaling, also leave them vulnerable to metabolic stress. Chandelier (Ch) cells are a type of PV+ interneuron that modulate the output of pyramidal neurons and synchronize spikes within neuron populations by directly innervating the pyramidal axon initial segment. Changes in the morphology and/or function of PV+ interneurons, mostly of Ch cells, are linked to neurological disorders. In ASD, the number of PV+ Ch cells is decreased across several cortical areas. Changes in the morphology and/or function of PV+ interneurons have also been linked to schizophrenia, epilepsy, and bipolar disorder. Herein, we review the role of PV and PV+ Ch cell alterations in ASD and other psychiatric disorders.
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Affiliation(s)
- Pablo Juarez
- Institute for Pediatric Regenerative Medicine (IPRM), Shriners Hospital for Children and UC Davis School of Medicine, Sacramento, CA, United States.,Department of Pathology and Laboratory Medicine, UC Davis School of Medicine, Sacramento, CA, United States
| | - Verónica Martínez Cerdeño
- Institute for Pediatric Regenerative Medicine (IPRM), Shriners Hospital for Children and UC Davis School of Medicine, Sacramento, CA, United States.,Department of Pathology and Laboratory Medicine, UC Davis School of Medicine, Sacramento, CA, United States.,MIND Institute, UC Davis School of Medicine, Sacramento, CA, United States
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8
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Ruiter M, Herstel LJ, Wierenga CJ. Reduction of Dendritic Inhibition in CA1 Pyramidal Neurons in Amyloidosis Models of Early Alzheimer's Disease. J Alzheimers Dis 2021; 78:951-964. [PMID: 33074225 PMCID: PMC7739974 DOI: 10.3233/jad-200527] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Background: In an early stage of Alzheimer’s disease (AD), before the formation of amyloid plaques, neuronal network hyperactivity has been reported in both patients and animal models. This suggests an underlying disturbance of the balance between excitation and inhibition. Several studies have highlighted the role of somatic inhibition in early AD, while less is known about dendritic inhibition. Objective: In this study we investigated how inhibitory synaptic currents are affected by elevated Aβ levels. Methods: We performed whole-cell patch clamp recordings of CA1 pyramidal neurons in organotypic hippocampal slice cultures after treatment with Aβ-oligomers and in hippocampal brain slices from AppNL-F-G mice (APP-KI). Results: We found a reduction of spontaneous inhibitory postsynaptic currents (sIPSCs) in CA1 pyramidal neurons in organotypic slices after 24 h Aβ treatment. sIPSCs with slow rise times were reduced, suggesting a specific loss of dendritic inhibitory inputs. As miniature IPSCs and synaptic density were unaffected, these results suggest a decrease in activity-dependent transmission after Aβ treatment. We observed a similar, although weaker, reduction in sIPSCs in CA1 pyramidal neurons from APP-KI mice compared to control. When separated by sex, the strongest reduction in sIPSC frequency was found in slices from male APP-KI mice. Consistent with hyperexcitability in pyramidal cells, dendritically targeting interneurons received slightly more excitatory input. GABAergic action potentials had faster kinetics in APP-KI slices. Conclusion: Our results show that Aβ affects dendritic inhibition via impaired action potential driven release, possibly due to altered kinetics of GABAergic action potentials. Reduced dendritic inhibition may contribute to neuronal hyperactivity in early AD.
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Affiliation(s)
- Marvin Ruiter
- Department of Cell Biology, Neurobiology and Biophysics, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Lotte J Herstel
- Department of Cell Biology, Neurobiology and Biophysics, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Corette J Wierenga
- Department of Cell Biology, Neurobiology and Biophysics, Faculty of Science, Utrecht University, Utrecht, The Netherlands
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9
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Hattori K, Hayakawa T, Nakanishi A, Ishida M, Yamamoto H, Hirano-Iwata A, Tanii T. Contribution of AMPA and NMDA receptors in the spontaneous firing patterns of single neurons in autaptic culture. Biosystems 2020; 198:104278. [PMID: 33075473 DOI: 10.1016/j.biosystems.2020.104278] [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: 03/29/2020] [Revised: 10/11/2020] [Accepted: 10/14/2020] [Indexed: 10/23/2022]
Abstract
Single neurons in an autaptic culture exhibit various types of firing pattern with different firing durations and rhythms. However, a neuron with autapses has often been modeled as an oscillator providing a monotonic firing pattern with a constant periodicity because of the lack of a mathematical model. In the work described in this study, we use computational simulation and whole-cell patch-clamp recording to elucidate and model the mechanism by which such neurons generate various firing pattens. In the computational simulation, three types of spontaneous firing pattern, i.e., short, long-lasting, and periodic burst firing patterns are realized by changing the combination ratio of N-methyl-d-aspartate (NMDA) to α-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate (AMPA) conductance. These three types of firing patterns are also observed in the experiments where neurons are cultured in isolation on micropatterned substrates. Using the AMPA and NMDA current models, we discuss that, in principle, autapses can regulate rhythmicity and information selection in neuronal networks.
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Affiliation(s)
- Kouhei Hattori
- Waseda University, Faculty of Science and Engineering, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555, Japan.
| | - Takeshi Hayakawa
- Tohoku University, Research Institute of Electrical Communication, 2-1-1 Katahira, Aoba, Sendai 980-8577, Japan
| | - Akira Nakanishi
- Waseda University, Faculty of Science and Engineering, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555, Japan
| | - Mihoko Ishida
- Waseda University, Faculty of Science and Engineering, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555, Japan
| | - Hideaki Yamamoto
- Tohoku University, Research Institute of Electrical Communication, 2-1-1 Katahira, Aoba, Sendai 980-8577, Japan
| | - Ayumi Hirano-Iwata
- Tohoku University, Research Institute of Electrical Communication, 2-1-1 Katahira, Aoba, Sendai 980-8577, Japan; Tohoku University, WPI-Advanced Institute for Materials Research (WPI-AIMR), 2-1-1 Katahira, Aoba, Sendai 980-8577, Japan
| | - Takashi Tanii
- Waseda University, Faculty of Science and Engineering, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555, Japan
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10
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Generation of Sharp Wave-Ripple Events by Disinhibition. J Neurosci 2020; 40:7811-7836. [PMID: 32913107 PMCID: PMC7548694 DOI: 10.1523/jneurosci.2174-19.2020] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 06/29/2020] [Accepted: 07/17/2020] [Indexed: 11/21/2022] Open
Abstract
Sharp wave-ripple complexes (SWRs) are hippocampal network phenomena involved in memory consolidation. To date, the mechanisms underlying their occurrence remain obscure. Here, we show how the interactions between pyramidal cells, parvalbumin-positive (PV+) basket cells, and an unidentified class of anti-SWR interneurons can contribute to the initiation and termination of SWRs. Using a biophysically constrained model of a network of spiking neurons and a rate-model approximation, we demonstrate that SWRs emerge as a result of the competition between two interneuron populations and the resulting disinhibition of pyramidal cells. Our models explain how the activation of pyramidal cells or PV+ cells can trigger SWRs, as shown in vitro, and suggests that PV+ cell-mediated short-term synaptic depression influences the experimentally reported dynamics of SWR events. Furthermore, we predict that the silencing of anti-SWR interneurons can trigger SWRs. These results broaden our understanding of the microcircuits supporting the generation of memory-related network dynamics. SIGNIFICANCE STATEMENT The hippocampus is a part of the mammalian brain that is crucial for episodic memories. During periods of sleep and inactive waking, the extracellular activity of the hippocampus is dominated by sharp wave-ripple events (SWRs), which have been shown to be important for memory consolidation. The mechanisms regulating the emergence of these events are still unclear. We developed a computational model to study the emergence of SWRs and to explain the roles of different cell types in regulating them. The model accounts for several previously unexplained features of SWRs and thus advances the understanding of memory-related dynamics.
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11
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Ecker A, Romani A, Sáray S, Káli S, Migliore M, Falck J, Lange S, Mercer A, Thomson AM, Muller E, Reimann MW, Ramaswamy S. Data-driven integration of hippocampal CA1 synaptic physiology in silico. Hippocampus 2020; 30:1129-1145. [PMID: 32520422 PMCID: PMC7687201 DOI: 10.1002/hipo.23220] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 04/20/2020] [Accepted: 05/07/2020] [Indexed: 12/31/2022]
Abstract
The anatomy and physiology of monosynaptic connections in rodent hippocampal CA1 have been extensively studied in recent decades. Yet, the resulting knowledge remains disparate and difficult to reconcile. Here, we present a data‐driven approach to integrate the current state‐of‐the‐art knowledge on the synaptic anatomy and physiology of rodent hippocampal CA1, including axo‐dendritic innervation patterns, number of synapses per connection, quantal conductances, neurotransmitter release probability, and short‐term plasticity into a single coherent resource. First, we undertook an extensive literature review of paired recordings of hippocampal neurons and compiled experimental data on their synaptic anatomy and physiology. The data collected in this manner is sparse and inhomogeneous due to the diversity of experimental techniques used by different groups, which necessitates the need for an integrative framework to unify these data. To this end, we extended a previously developed workflow for the neocortex to constrain a unifying in silico reconstruction of the synaptic physiology of CA1 connections. Our work identifies gaps in the existing knowledge and provides a complementary resource toward a more complete quantification of synaptic anatomy and physiology in the rodent hippocampal CA1 region.
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Affiliation(s)
- András Ecker
- Blue Brain Project, École Polytechnique Fédérale de Lausanne, Campus Biotech, Geneva, Switzerland
| | - Armando Romani
- Blue Brain Project, École Polytechnique Fédérale de Lausanne, Campus Biotech, Geneva, Switzerland
| | - Sára Sáray
- Institute of Experimental Medicine, Budapest, Hungary.,Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Budapest, Hungary
| | - Szabolcs Káli
- Institute of Experimental Medicine, Budapest, Hungary.,Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Budapest, Hungary
| | - Michele Migliore
- Institute of Biophysics, National Research Council, Palermo, Italy
| | - Joanne Falck
- UCL School of Pharmacy, University College London, London, UK
| | - Sigrun Lange
- UCL School of Pharmacy, University College London, London, UK.,School of Life Sciences, University of Westminster, London, UK
| | - Audrey Mercer
- UCL School of Pharmacy, University College London, London, UK
| | - Alex M Thomson
- UCL School of Pharmacy, University College London, London, UK
| | - Eilif Muller
- Blue Brain Project, École Polytechnique Fédérale de Lausanne, Campus Biotech, Geneva, Switzerland
| | - Michael W Reimann
- Blue Brain Project, École Polytechnique Fédérale de Lausanne, Campus Biotech, Geneva, Switzerland
| | - Srikanth Ramaswamy
- Blue Brain Project, École Polytechnique Fédérale de Lausanne, Campus Biotech, Geneva, Switzerland
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12
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Guet-McCreight A, Skinner FK, Topolnik L. Common Principles in Functional Organization of VIP/Calretinin Cell-Driven Disinhibitory Circuits Across Cortical Areas. Front Neural Circuits 2020; 14:32. [PMID: 32581726 PMCID: PMC7296096 DOI: 10.3389/fncir.2020.00032] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 05/04/2020] [Indexed: 12/21/2022] Open
Abstract
In the brain, there is a vast diversity of different structures, circuitries, cell types, and cellular genetic expression profiles. While this large diversity can often occlude a clear understanding of how the brain works, careful analyses of analogous studies performed across different brain areas can hint at commonalities in neuronal organization. This in turn can yield a fundamental understanding of necessary circuitry components that are crucial for how information is processed across the brain. In this review, we outline recent in vivo and in vitro studies that have been performed in different cortical areas to characterize the vasoactive intestinal polypeptide (VIP)- and/or calretinin (CR)-expressing cells that specialize in inhibiting GABAergic interneurons. In doing so, we make the case that, across cortical structures, interneuron-specific cells commonly specialize in the synaptic disinhibition of excitatory neurons, which can ungate the integration and plasticity of external inputs onto excitatory neurons. In line with this, activation of interneuron- specific cells enhances animal performance across a variety of behavioral tasks that involve learning, memory formation, and sensory discrimination, and may represent a key target for therapeutic interventions under different pathological conditions. As such, interneuron-specific cells across different cortical structures are an essential network component for information processing and normal brain function.
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Affiliation(s)
- Alexandre Guet-McCreight
- Krembil Brain Institute - Division of Clinical and Computational Neuroscience, Krembil Research Institute, University Health Network, Toronto, ON, Canada.,Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Frances K Skinner
- Krembil Brain Institute - Division of Clinical and Computational Neuroscience, Krembil Research Institute, University Health Network, Toronto, ON, Canada.,Department of Physiology, University of Toronto, Toronto, ON, Canada.,Department of Medicine (Neurology), University of Toronto, Toronto, ON, Canada
| | - Lisa Topolnik
- Department of Biochemistry, Microbiology and Bio-informatics, Laval University, Québec, QC, Canada.,Neuroscience Axis, CHU de Québec Research Center (CHUL), Québec, QC, Canada
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13
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Shunting Inhibition Improves Synchronization in Heterogeneous Inhibitory Interneuronal Networks with Type 1 Excitability Whereas Hyperpolarizing Inhibition Is Better for Type 2 Excitability. eNeuro 2020; 7:ENEURO.0464-19.2020. [PMID: 32198159 PMCID: PMC7210489 DOI: 10.1523/eneuro.0464-19.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 03/01/2020] [Accepted: 03/10/2020] [Indexed: 11/27/2022] Open
Abstract
All-to-all homogeneous networks of inhibitory neurons synchronize completely under the right conditions; however, many modeling studies have shown that biological levels of heterogeneity disrupt synchrony. Our fundamental scientific question is “how can neurons maintain partial synchrony in the presence of heterogeneity and noise?” A particular subset of strongly interconnected interneurons, the PV+ fast-spiking (FS) basket neurons, are strongly implicated in γ oscillations and in phase locking of nested γ oscillations to theta. Their excitability type apparently varies between brain regions: in CA1 and the dentate gyrus they have type 1 excitability, meaning that they can fire arbitrarily slowly, whereas in the striatum and cortex they have type 2 excitability, meaning that there is a frequency thresh old below which they cannot sustain repetitive firing. We constrained the models to study the effect of excitability type (more precisely bifurcation type) in isolation from all other factors. We use sparsely connected, heterogeneous, noisy networks with synaptic delays to show that synchronization properties, namely the resistance to suppression and the strength of theta phase to γ amplitude coupling, are strongly dependent on the pairing of excitability type with the type of inhibition. Shunting inhibition performs better for type 1 and hyperpolarizing inhibition for type 2. γ Oscillations and their nesting within theta oscillations are thought to subserve cognitive functions like memory encoding and recall; therefore, it is important to understand the contribution of intrinsic properties to these rhythms.
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Bekkers JM. Autaptic Cultures: Methods and Applications. Front Synaptic Neurosci 2020; 12:18. [PMID: 32425765 PMCID: PMC7203343 DOI: 10.3389/fnsyn.2020.00018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Accepted: 04/01/2020] [Indexed: 11/13/2022] Open
Abstract
Neurons typically form daisy chains of synaptic connections with other neurons, but they can also form synapses with themselves. Although such self-synapses, or autapses, are comparatively rare in vivo, they are surprisingly common in dissociated neuronal cultures. At first glance, autapses in culture seem like a mere curiosity. However, by providing a simple model system in which a single recording electrode gives simultaneous access to the pre- and postsynaptic compartments, autaptic cultures have proven to be invaluable in facilitating important and elegant experiments in the area of synaptic neuroscience. Here, I provide detailed protocols for preparing and recording from autaptic cultures (also called micro-island or microdot cultures). Variations on the basic procedure are presented, as well as practical tips for optimizing the outcomes. I also illustrate the utility of autaptic cultures by reviewing the types of experiments that have used them over the past three decades. These examples serve to highlight the power and elegance of this simple model system, and will hopefully inspire new experiments for the interrogation of synaptic function.
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Affiliation(s)
- John M Bekkers
- Eccles Institute of Neuroscience, The John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia
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15
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Zhao Z, Li L, Gu H. Different dynamical behaviors induced by slow excitatory feedback for type II and III excitabilities. Sci Rep 2020; 10:3646. [PMID: 32108168 PMCID: PMC7046675 DOI: 10.1038/s41598-020-60627-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2019] [Accepted: 02/14/2020] [Indexed: 11/13/2022] Open
Abstract
Neuronal excitability is classified as type I, II, or III, according to the responses of electronic activities, which play different roles. In the present paper, the effect of an excitatory autapse on type III excitability is investigated and compared to type II excitability in the Morris-Lecar model, based on Hopf bifurcation and characteristics of the nullcline. The autaptic current of a fast-decay autapse produces periodic stimulations, and that of a slow-decay autapse highly resembles sustained stimulations. Thus, both fast- and slow-decay autapses can induce a resting state for type II excitability that changes to repetitive firing. However, for type III excitability, a fast-decay autapse can induce a resting state to change to repetitive firing, while a slow-decay autapse can induce a resting state to change to a resting state following a transient spike instead of repetitive spiking, which shows the abnormal phenomenon that a stronger excitatory effect of a slow-decay autapse just induces weaker responses. Our results uncover a novel paradoxical phenomenon of the excitatory effect, and we present potential functions of fast- and slow-decay autapses that are helpful for the alteration and maintenance of type III excitability in the real nervous system related to neuropathic pain or sound localization.
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Affiliation(s)
- Zhiguo Zhao
- School of Science, Henan Institute of Technology, Xinxiang, 453003, China
| | - Li Li
- Guangdong Key Laboratory of Modern Control Technology, Guangdong Institute of Intelligent Manufacturing, Guangzhou, 510070, China
| | - Huaguang Gu
- School of Aerospace Engineering and Applied Mechanics, Tongji University, Shanghai, 200092, China.
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Szegedi V, Paizs M, Baka J, Barzó P, Molnár G, Tamas G, Lamsa K. Robust perisomatic GABAergic self-innervation inhibits basket cells in the human and mouse supragranular neocortex. eLife 2020; 9:51691. [PMID: 31916939 PMCID: PMC6984819 DOI: 10.7554/elife.51691] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 01/08/2020] [Indexed: 01/08/2023] Open
Abstract
Inhibitory autapses are self-innervating synaptic connections in GABAergic interneurons in the brain. Autapses in neocortical layers have not been systematically investigated, and their function in different mammalian species and specific interneuron types is poorly known. We investigated GABAergic parvalbumin-expressing basket cells (pvBCs) in layer 2/3 (L2/3) in human neocortical tissue resected in deep-brain surgery, and in mice as control. Most pvBCs showed robust GABAAR-mediated self-innervation in both species, but autapses were rare in nonfast-spiking GABAergic interneurons. Light- and electron microscopy analyses revealed pvBC axons innervating their own soma and proximal dendrites. GABAergic self-inhibition conductance was similar in human and mouse pvBCs and comparable to that of synapses from pvBCs to other L2/3 neurons. Autaptic conductance prolonged somatic inhibition in pvBCs after a spike and inhibited repetitive firing. Perisomatic autaptic inhibition is common in both human and mouse pvBCs of supragranular neocortex, where they efficiently control discharge of the pvBCs.
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Affiliation(s)
- Viktor Szegedi
- MTA-NAP Research Group for Inhibitory Interneurons and Plasticity, Department of Physiology, Anatomy and Neuroscience, University of Szeged, Szeged, Hungary
| | - Melinda Paizs
- MTA-NAP Research Group for Inhibitory Interneurons and Plasticity, Department of Physiology, Anatomy and Neuroscience, University of Szeged, Szeged, Hungary
| | - Judith Baka
- MTA-SZTE Research Group for Cortical Microcircuits, Department of Physiology, Anatomy and Neuroscience, University of Szeged, Szeged, Hungary
| | - Pál Barzó
- Department of Neurosurgery, University of Szeged, Szeged, Hungary
| | - Gábor Molnár
- MTA-SZTE Research Group for Cortical Microcircuits, Department of Physiology, Anatomy and Neuroscience, University of Szeged, Szeged, Hungary
| | - Gabor Tamas
- MTA-SZTE Research Group for Cortical Microcircuits, Department of Physiology, Anatomy and Neuroscience, University of Szeged, Szeged, Hungary
| | - Karri Lamsa
- MTA-NAP Research Group for Inhibitory Interneurons and Plasticity, Department of Physiology, Anatomy and Neuroscience, University of Szeged, Szeged, Hungary
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17
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Krajcovic B, Fajnerova I, Horacek J, Kelemen E, Kubik S, Svoboda J, Stuchlik A. Neural and neuronal discoordination in schizophrenia: From ensembles through networks to symptoms. Acta Physiol (Oxf) 2019; 226:e13282. [PMID: 31002202 DOI: 10.1111/apha.13282] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 03/27/2019] [Accepted: 04/12/2019] [Indexed: 12/22/2022]
Abstract
Despite the substantial knowledge accumulated by past research, the exact mechanisms of the pathogenesis of schizophrenia and causal treatments still remain unclear. Deficits of cognition and information processing in schizophrenia are today often viewed as the primary and core symptoms of this devastating disorder. These deficits likely result from disruptions in the coordination of neuronal and neural activity. The aim of this review is to bring together convergent evidence of discoordinated brain circuits in schizophrenia at multiple levels of resolution, ranging from principal cells and interneurons, neuronal ensembles and local circuits, to large-scale brain networks. We show how these aberrations could underlie deficits in cognitive control and other higher order cognitive-behavioural functions. Converging evidence from both animal models and patients with schizophrenia is presented in an effort to gain insight into common features of deficits in the brain information processing in this disorder, marked by disruption of several neurotransmitter and signalling systems and severe behavioural outcomes.
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Affiliation(s)
- Branislav Krajcovic
- Department of Neurophysiology of Memory Institute of Physiology of the Czech Academy of Sciences Prague Czech Republic
- Third Faculty of Medicine Charles University Prague Czech Republic
| | - Iveta Fajnerova
- Department of Neurophysiology of Memory Institute of Physiology of the Czech Academy of Sciences Prague Czech Republic
- Research Programme 3 - Applied Neurosciences and Brain Imaging National Institute of Mental Health Klecany Czech Republic
| | - Jiri Horacek
- Third Faculty of Medicine Charles University Prague Czech Republic
- Research Programme 3 - Applied Neurosciences and Brain Imaging National Institute of Mental Health Klecany Czech Republic
| | - Eduard Kelemen
- Research Programme 1 - Experimental Neurobiology National Institute of Mental Health Klecany Czech Republic
| | - Stepan Kubik
- Department of Neurophysiology of Memory Institute of Physiology of the Czech Academy of Sciences Prague Czech Republic
| | - Jan Svoboda
- Department of Neurophysiology of Memory Institute of Physiology of the Czech Academy of Sciences Prague Czech Republic
| | - Ales Stuchlik
- Department of Neurophysiology of Memory Institute of Physiology of the Czech Academy of Sciences Prague Czech Republic
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18
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Yin L, Zheng R, Ke W, He Q, Zhang Y, Li J, Wang B, Mi Z, Long YS, Rasch MJ, Li T, Luan G, Shu Y. Autapses enhance bursting and coincidence detection in neocortical pyramidal cells. Nat Commun 2018; 9:4890. [PMID: 30459347 PMCID: PMC6244208 DOI: 10.1038/s41467-018-07317-4] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 10/23/2018] [Indexed: 01/19/2023] Open
Abstract
Autapses are synaptic contacts of a neuron’s axon onto its own dendrite and soma. In the neocortex, self-inhibiting autapses in GABAergic interneurons are abundant in number and play critical roles in regulating spike precision and network activity. Here we examine whether the principal glutamatergic pyramidal cells (PCs) also form functional autapses. In patch-clamp recording from both rodent and human PCs, we isolated autaptic responses and found that these occur predominantly in layer-5 PCs projecting to subcortical regions, with very few in those projecting to contralateral prefrontal cortex and layer 2/3 PCs. Moreover, PC autapses persist during development into adulthood. Surprisingly, they produce giant postsynaptic responses (∼5 fold greater than recurrent PC-PC synapses) that are exclusively mediated by AMPA receptors. Upon activation, autapses enhance burst firing, neuronal responsiveness and coincidence detection of synaptic inputs. These findings indicate that PC autapses are functional and represent an important circuit element in the neocortex. While autapses are synapses made by a neuron onto itself, its functional significance in pyramidal cells are not clear. Here, the authors show that in the mammalian neocortex, autapses of pyramidal cells can enhance burst firing and coincidence detection from other inputs.
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Affiliation(s)
- Luping Yin
- State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, 19 Xinjiekou Wai Street, Beijing, 100875, China.,Institute of Neuroscience and State Key Laboratory of Neuroscience, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 320 Yueyang Road, Shanghai, 200031, China
| | - Rui Zheng
- State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, 19 Xinjiekou Wai Street, Beijing, 100875, China.,Institute of Neuroscience and State Key Laboratory of Neuroscience, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 320 Yueyang Road, Shanghai, 200031, China
| | - Wei Ke
- State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, 19 Xinjiekou Wai Street, Beijing, 100875, China
| | - Quansheng He
- State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, 19 Xinjiekou Wai Street, Beijing, 100875, China
| | - Yi Zhang
- State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, 19 Xinjiekou Wai Street, Beijing, 100875, China
| | - Junlong Li
- State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, 19 Xinjiekou Wai Street, Beijing, 100875, China
| | - Bo Wang
- State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, 19 Xinjiekou Wai Street, Beijing, 100875, China.,Institute of Neuroscience and State Key Laboratory of Neuroscience, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 320 Yueyang Road, Shanghai, 200031, China
| | - Zhen Mi
- State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, 19 Xinjiekou Wai Street, Beijing, 100875, China
| | - Yue-Sheng Long
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, 501260, China
| | - Malte J Rasch
- State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, 19 Xinjiekou Wai Street, Beijing, 100875, China
| | - Tianfu Li
- Department of Neurology, Epilepsy Center, Sanbo Brain Hospital, Capital Medical University, Xiangshan Yikesong 50, Beijing, 100093, China
| | - Guoming Luan
- Department of Neurosurgery, Epilepsy Center, Sanbo Brain Hospital, Capital Medical University, Xiangshan Yikesong 50, Beijing, 100093, China
| | - Yousheng Shu
- State Key Laboratory of Cognitive Neuroscience and Learning & IDG/McGovern Institute for Brain Research, Beijing Normal University, 19 Xinjiekou Wai Street, Beijing, 100875, China.
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19
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Szodorai E, Bampali K, Romanov RA, Kasper S, Hökfelt T, Ernst M, Lubec G, Harkany T. Diversity matters: combinatorial information coding by GABA A receptor subunits during spatial learning and its allosteric modulation. Cell Signal 2018; 50:142-159. [DOI: 10.1016/j.cellsig.2018.07.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 07/08/2018] [Accepted: 07/09/2018] [Indexed: 01/11/2023]
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20
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Cardin JA. Inhibitory Interneurons Regulate Temporal Precision and Correlations in Cortical Circuits. Trends Neurosci 2018; 41:689-700. [PMID: 30274604 PMCID: PMC6173199 DOI: 10.1016/j.tins.2018.07.015] [Citation(s) in RCA: 126] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2018] [Revised: 07/24/2018] [Accepted: 07/31/2018] [Indexed: 01/16/2023]
Abstract
GABAergic interneurons, which are highly diverse, have long been thought to contribute to the timing of neural activity as well as to the generation and shaping of brain rhythms. GABAergic activity is crucial not only for entrainment of oscillatory activity across a neural population, but also for precise regulation of the timing of action potentials and the suppression of slow-timescale correlations. The diversity of inhibition provides the potential for flexible regulation of patterned activity, but also poses a challenge to identifying the elements of excitatory-inhibitory interactions underlying network engagement. This review highlights the key roles of inhibitory interneurons in spike correlations and brain rhythms, describes several scales on which GABAergic inhibition regulates timing in neural networks, and identifies potential consequences of inhibitory dysfunction.
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Affiliation(s)
- Jessica A Cardin
- Department of Neuroscience, Yale University, New Haven, CT 06520, USA; Kavli Institute for Neuroscience, Yale University, New Haven, CT 06520, USA.
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21
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Booker SA, Vida I. Morphological diversity and connectivity of hippocampal interneurons. Cell Tissue Res 2018; 373:619-641. [PMID: 30084021 PMCID: PMC6132631 DOI: 10.1007/s00441-018-2882-2] [Citation(s) in RCA: 102] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 07/03/2018] [Indexed: 12/21/2022]
Abstract
The mammalian forebrain is constructed from ensembles of neurons that form local microcircuits giving rise to the exquisite cognitive tasks the mammalian brain can perform. Hippocampal neuronal circuits comprise populations of relatively homogenous excitatory neurons, principal cells and exceedingly heterogeneous inhibitory neurons, the interneurons. Interneurons release GABA from their axon terminals and are capable of controlling excitability in every cellular compartment of principal cells and interneurons alike; thus, they provide a brake on excess activity, control the timing of neuronal discharge and provide modulation of synaptic transmission. The dendritic and axonal morphology of interneurons, as well as their afferent and efferent connections within hippocampal circuits, is central to their ability to differentially control excitability, in a cell-type- and compartment-specific manner. This review aims to provide an up-to-date compendium of described hippocampal interneuron subtypes, with respect to their morphology, connectivity, neurochemistry and physiology, a full understanding of which will in time help to explain the rich diversity of neuronal function.
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Affiliation(s)
- Sam A Booker
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK.
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, EH8 9XD, UK.
| | - Imre Vida
- Institute for Integrative Neuroanatomy, Charité - Universitätmedizin Berlin, Berlin, Germany.
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22
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Pelkey KA, Chittajallu R, Craig MT, Tricoire L, Wester JC, McBain CJ. Hippocampal GABAergic Inhibitory Interneurons. Physiol Rev 2017; 97:1619-1747. [PMID: 28954853 DOI: 10.1152/physrev.00007.2017] [Citation(s) in RCA: 481] [Impact Index Per Article: 68.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 05/16/2017] [Accepted: 05/26/2017] [Indexed: 12/11/2022] Open
Abstract
In the hippocampus GABAergic local circuit inhibitory interneurons represent only ~10-15% of the total neuronal population; however, their remarkable anatomical and physiological diversity allows them to regulate virtually all aspects of cellular and circuit function. Here we provide an overview of the current state of the field of interneuron research, focusing largely on the hippocampus. We discuss recent advances related to the various cell types, including their development and maturation, expression of subtype-specific voltage- and ligand-gated channels, and their roles in network oscillations. We also discuss recent technological advances and approaches that have permitted high-resolution, subtype-specific examination of their roles in numerous neural circuit disorders and the emerging therapeutic strategies to ameliorate such pathophysiological conditions. The ultimate goal of this review is not only to provide a touchstone for the current state of the field, but to help pave the way for future research by highlighting where gaps in our knowledge exist and how a complete appreciation of their roles will aid in future therapeutic strategies.
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Affiliation(s)
- Kenneth A Pelkey
- Porter Neuroscience Center, Eunice Kennedy-Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland; Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, Hatherly Laboratories, University of Exeter, Exeter, United Kingdom; and Sorbonne Universités, UPMC University of Paris, INSERM, CNRS, Neurosciences Paris Seine-Institut de Biologie Paris Seine, Paris, France
| | - Ramesh Chittajallu
- Porter Neuroscience Center, Eunice Kennedy-Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland; Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, Hatherly Laboratories, University of Exeter, Exeter, United Kingdom; and Sorbonne Universités, UPMC University of Paris, INSERM, CNRS, Neurosciences Paris Seine-Institut de Biologie Paris Seine, Paris, France
| | - Michael T Craig
- Porter Neuroscience Center, Eunice Kennedy-Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland; Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, Hatherly Laboratories, University of Exeter, Exeter, United Kingdom; and Sorbonne Universités, UPMC University of Paris, INSERM, CNRS, Neurosciences Paris Seine-Institut de Biologie Paris Seine, Paris, France
| | - Ludovic Tricoire
- Porter Neuroscience Center, Eunice Kennedy-Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland; Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, Hatherly Laboratories, University of Exeter, Exeter, United Kingdom; and Sorbonne Universités, UPMC University of Paris, INSERM, CNRS, Neurosciences Paris Seine-Institut de Biologie Paris Seine, Paris, France
| | - Jason C Wester
- Porter Neuroscience Center, Eunice Kennedy-Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland; Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, Hatherly Laboratories, University of Exeter, Exeter, United Kingdom; and Sorbonne Universités, UPMC University of Paris, INSERM, CNRS, Neurosciences Paris Seine-Institut de Biologie Paris Seine, Paris, France
| | - Chris J McBain
- Porter Neuroscience Center, Eunice Kennedy-Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland; Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, Hatherly Laboratories, University of Exeter, Exeter, United Kingdom; and Sorbonne Universités, UPMC University of Paris, INSERM, CNRS, Neurosciences Paris Seine-Institut de Biologie Paris Seine, Paris, France
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McKenzie S. Inhibition shapes the organization of hippocampal representations. Hippocampus 2017; 28:659-671. [PMID: 28921762 DOI: 10.1002/hipo.22803] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 09/11/2017] [Accepted: 09/13/2017] [Indexed: 01/12/2023]
Abstract
Hippocampal neurons become tuned to stimuli that predict behaviorally salient outcomes. This plasticity suggests that memory formation depends upon shifts in how different anatomical inputs can drive hippocampal activity. Here, I present evidence that inhibitory neurons can provide such a mechanism for learning-related changes in the tuning of pyramidal cells. Inhibitory currents arriving on the dendrites of pyramidal cells determine whether an excitatory input can drive action potential output. Specificity and plasticity of this dendritic modulation allows for precise, modifiable changes in how afferent inputs are integrated, a process that defines a neuron's receptive field. In addition, feedback inhibition plays a fundamental role in biasing which excitatory neurons may be co-active. By defining the rules of synchrony and the rules of input integration, interneurons likely play an important role in the organization of memory representation within the hippocampus.
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Affiliation(s)
- Sam McKenzie
- NYU Langone Medical Center, 450 E29th Street, 9th Floor, New York, New York 10016
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24
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Zhao Z, Gu H. Transitions between classes of neuronal excitability and bifurcations induced by autapse. Sci Rep 2017; 7:6760. [PMID: 28755006 PMCID: PMC5533805 DOI: 10.1038/s41598-017-07051-9] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Accepted: 06/21/2017] [Indexed: 11/10/2022] Open
Abstract
Neuronal excitabilities behave as the basic and important dynamics related to the transitions between firing and resting states, and are characterized by distinct bifurcation types and spiking frequency responses. Switches between class I and II excitabilities induced by modulations outside the neuron (for example, modulation to M-type potassium current) have been one of the most concerning issues in both electrophysiology and nonlinear dynamics. In the present paper, we identified switches between 2 classes of excitability and firing frequency responses when an autapse, which widely exists in real nervous systems and plays important roles via self-feedback, is introduced into the Morris-Lecar (ML) model neuron. The transition from class I to class II excitability and from class II to class I spiking frequency responses were respectively induced by the inhibitory and excitatory autapse, which are characterized by changes of bifurcations, frequency responses, steady-state current-potential curves, and nullclines. Furthermore, we identified codimension-1 and -2 bifurcations and the characteristics of the current-potential curve that determine the transitions. Our results presented a comprehensive relationship between 2 classes of neuronal excitability/spiking characterized by different types of bifurcations, along with a novel possible function of autapse or self-feedback control on modulating neuronal excitability.
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Affiliation(s)
- Zhiguo Zhao
- School of Aerospace Engineering and Applied Mechanics, Tongji University, Shanghai, 200092, China
| | - Huaguang Gu
- School of Aerospace Engineering and Applied Mechanics, Tongji University, Shanghai, 200092, China.
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25
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Excitatory Inputs Determine Phase-Locking Strength and Spike-Timing of CA1 Stratum Oriens/Alveus Parvalbumin and Somatostatin Interneurons during Intrinsically Generated Hippocampal Theta Rhythm. J Neurosci 2017; 36:6605-22. [PMID: 27335395 DOI: 10.1523/jneurosci.3951-13.2016] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Accepted: 04/14/2016] [Indexed: 01/20/2023] Open
Abstract
UNLABELLED Theta oscillations are essential for learning and memory, and their generation requires GABAergic interneurons. To better understand how theta is generated, we explored how parvalbumin (PV) and somatostatin (SOM) interneurons in CA1 stratum oriens/alveus fire during hippocampal theta and investigated synaptic mechanisms underlying their behavior. Combining the use of transgenic mice to visually identify PV and SOM interneurons and the intact hippocampal preparation that can generate theta oscillations in vitro without cholinergic agonists, we performed simultaneous field and whole-cell recordings. We found that PV interneurons uniformly fire strongly phase-locked to theta, whereas SOM neurons are more heterogeneous with only a proportion of cells displaying tight phase-locking. Differences in phase-locking strength could be explained by disparity in excitatory inputs received; PV neurons received significantly larger EPSCs compared with SOM neurons, and the degree of phase-locking in SOM neurons was significantly correlated with the size of EPSCs. In contrast, IPSC amplitude did not differ between cell types. We determined that the local CA1 rhythm plays a more dominant role in driving CA1 interneuron firing than afferent inputs from the CA3. Last, we show that PV and strongly phase-locked SOM neurons fire near the peak of CA1 theta, under the tight control of excitatory inputs that arise at a specific phase of each theta cycle. These results reveal a fundamental mechanism of neuronal phase-locking and highlight an important role of excitation from the local network in governing firing behavior during rhythmic network states. SIGNIFICANCE STATEMENT Rhythmic activity in the theta range (3-12 Hz) is important for proper functioning of the hippocampus, a brain area essential for learning and memory. To understand how theta rhythm is generated, we investigated how two types of inhibitory neurons, those that express parvalbumin and somatostatin, fire action potentials during theta in an in vitro preparation of the mouse hippocampus. We found that the amount of excitatory input they receive from the local network determines how closely their spikes follow the network theta rhythm. Our findings reveal an important role of local excitatory input in driving inhibitory neuron firing during rhythmic states and may have implications for diseases, such as epilepsy and Alzheimer's disease, which affect the hippocampus and related areas.
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Wiles L, Gu S, Pasqualetti F, Parvesse B, Gabrieli D, Bassett DS, Meaney DF. Autaptic Connections Shift Network Excitability and Bursting. Sci Rep 2017; 7:44006. [PMID: 28266594 PMCID: PMC5339801 DOI: 10.1038/srep44006] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 02/02/2017] [Indexed: 12/01/2022] Open
Abstract
We examine the role of structural autapses, when a neuron synapses onto itself, in driving network-wide bursting behavior. Using a simple spiking model of neuronal activity, we study how autaptic connections affect activity patterns, and evaluate if controllability significantly affects changes in bursting from autaptic connections. Adding more autaptic connections to excitatory neurons increased the number of spiking events and the number of network-wide bursts. We observed excitatory synapses contributed more to bursting behavior than inhibitory synapses. We evaluated if neurons with high average controllability, predicted to push the network into easily achievable states, affected bursting behavior differently than neurons with high modal controllability, thought to influence the network into difficult to reach states. Results show autaptic connections to excitatory neurons with high average controllability led to higher burst frequencies than adding the same number of self-looping connections to neurons with high modal controllability. The number of autapses required to induce bursting was lowered by adding autapses to high degree excitatory neurons. These results suggest a role of autaptic connections in controlling network-wide bursts in diverse cortical and subcortical regions of mammalian brain. Moreover, they open up new avenues for the study of dynamic neurophysiological correlates of structural controllability.
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Affiliation(s)
- Laura Wiles
- Department of Bioengineering, School of Engineering and Applied Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Shi Gu
- Department of Bioengineering, School of Engineering and Applied Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA
- Applied Mathematics and Computational Science Graduate Program, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Fabio Pasqualetti
- Department of Mechanical Engineering, University of California Riverside, CA, USA
| | - Brandon Parvesse
- Department of Bioengineering, School of Engineering and Applied Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - David Gabrieli
- Department of Bioengineering, School of Engineering and Applied Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Danielle S. Bassett
- Department of Bioengineering, School of Engineering and Applied Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Electrical and Systems Engineering, School of Engineering and Applied Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - David F. Meaney
- Department of Bioengineering, School of Engineering and Applied Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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27
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Bezaire MJ, Raikov I, Burk K, Vyas D, Soltesz I. Interneuronal mechanisms of hippocampal theta oscillations in a full-scale model of the rodent CA1 circuit. eLife 2016; 5:e18566. [PMID: 28009257 DOI: 10.7554/elife.18566.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2016] [Accepted: 12/15/2016] [Indexed: 05/25/2023] Open
Abstract
The hippocampal theta rhythm plays important roles in information processing; however, the mechanisms of its generation are not well understood. We developed a data-driven, supercomputer-based, full-scale (1:1) model of the rodent CA1 area and studied its interneurons during theta oscillations. Theta rhythm with phase-locked gamma oscillations and phase-preferential discharges of distinct interneuronal types spontaneously emerged from the isolated CA1 circuit without rhythmic inputs. Perturbation experiments identified parvalbumin-expressing interneurons and neurogliaform cells, as well as interneuronal diversity itself, as important factors in theta generation. These simulations reveal new insights into the spatiotemporal organization of the CA1 circuit during theta oscillations.
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Affiliation(s)
- Marianne J Bezaire
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, United States
| | - Ivan Raikov
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, United States
- Department of Neurosurgery, Stanford University, Stanford, United States
| | - Kelly Burk
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, United States
| | - Dhrumil Vyas
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, United States
| | - Ivan Soltesz
- Department of Neurosurgery, Stanford University, Stanford, United States
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28
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Bezaire MJ, Raikov I, Burk K, Vyas D, Soltesz I. Interneuronal mechanisms of hippocampal theta oscillations in a full-scale model of the rodent CA1 circuit. eLife 2016; 5. [PMID: 28009257 PMCID: PMC5313080 DOI: 10.7554/elife.18566] [Citation(s) in RCA: 107] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2016] [Accepted: 12/15/2016] [Indexed: 12/16/2022] Open
Abstract
The hippocampal theta rhythm plays important roles in information processing; however, the mechanisms of its generation are not well understood. We developed a data-driven, supercomputer-based, full-scale (1:1) model of the rodent CA1 area and studied its interneurons during theta oscillations. Theta rhythm with phase-locked gamma oscillations and phase-preferential discharges of distinct interneuronal types spontaneously emerged from the isolated CA1 circuit without rhythmic inputs. Perturbation experiments identified parvalbumin-expressing interneurons and neurogliaform cells, as well as interneuronal diversity itself, as important factors in theta generation. These simulations reveal new insights into the spatiotemporal organization of the CA1 circuit during theta oscillations. DOI:http://dx.doi.org/10.7554/eLife.18566.001
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Affiliation(s)
- Marianne J Bezaire
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, United States
| | - Ivan Raikov
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, United States.,Department of Neurosurgery, Stanford University, Stanford, United States
| | - Kelly Burk
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, United States
| | - Dhrumil Vyas
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, United States
| | - Ivan Soltesz
- Department of Neurosurgery, Stanford University, Stanford, United States
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29
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Cardin JA. Snapshots of the Brain in Action: Local Circuit Operations through the Lens of γ Oscillations. J Neurosci 2016; 36:10496-10504. [PMID: 27733601 PMCID: PMC5059425 DOI: 10.1523/jneurosci.1021-16.2016] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 06/17/2016] [Accepted: 07/23/2016] [Indexed: 11/21/2022] Open
Abstract
γ oscillations (20-80 Hz) are associated with sensory processing, cognition, and memory, and focused attention in animals and humans. γ activity can arise from several neural mechanisms in the cortex and hippocampus and can vary across circuits, behavioral states, and developmental stages. γ oscillations are nonstationary, typically occurring in short bouts, and the peak frequency of this rhythm is modulated by stimulus parameters. In addition, the participation of excitatory and inhibitory neurons in the γ rhythm varies across local circuits and conditions, particularly in the cortex. Although these dynamics present a challenge to interpreting the functional role of γ oscillations, these patterns of activity emerge from synaptic interactions among excitatory and inhibitory neurons and thus provide important insight into local circuit operations.
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Affiliation(s)
- Jessica A Cardin
- Department of Neuroscience and Kavli Institute, Yale University, New Haven, Connecticut 06520
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30
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Merker BH. Cortical Gamma Oscillations: Details of Their Genesis Preclude a Role in Cognition. Front Comput Neurosci 2016; 10:78. [PMID: 27512371 PMCID: PMC4961686 DOI: 10.3389/fncom.2016.00078] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 07/14/2016] [Indexed: 11/13/2022] Open
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31
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Kohus Z, Káli S, Rovira‐Esteban L, Schlingloff D, Papp O, Freund TF, Hájos N, Gulyás AI. Properties and dynamics of inhibitory synaptic communication within the CA3 microcircuits of pyramidal cells and interneurons expressing parvalbumin or cholecystokinin. J Physiol 2016; 594:3745-74. [PMID: 27038232 PMCID: PMC4929320 DOI: 10.1113/jp272231] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 03/21/2016] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS To understand how a network operates, its elements must be identified and characterized, and the interactions of the elements need to be studied in detail. In the present study, we describe quantitatively the connectivity of two classes of inhibitory neurons in the hippocampal CA3 area (parvalbumin-positive and cholecystokinin-positive interneurons), a key region for the generation of behaviourally relevant synchronous activity patterns. We describe how interactions among these inhibitory cells and their local excitatory target neurons evolve over the course of physiological and pathological activity patterns. The results of the present study enable the construction of precise neuronal network models that may help us understand how network dynamics is generated and how it can underlie information processing and pathological conditions in the brain. We show how inhibitory dynamics between parvalbumin-positive basket cells and pyramidal cells could contribute to sharp wave-ripple generation. ABSTRACT Different hippocampal activity patterns are determined primarily by the interaction of excitatory cells and different types of interneurons. To understand the mechanisms underlying the generation of different network dynamics, the properties of synaptic transmission need to be uncovered. Perisomatic inhibition is critical for the generation of sharp wave-ripples, gamma oscillations and pathological epileptic activities. Therefore, we aimed to quantitatively and systematically characterize the temporal properties of the synaptic transmission between perisomatic inhibitory neurons and pyramidal cells in the CA3 area of mouse hippocampal slices, using action potential patterns recorded during physiological and pathological network states. Parvalbumin-positive (PV+) and cholecystokinin-positive (CCK+) interneurons showed distinct intrinsic physiological features. Interneurons of the same type formed reciprocally connected subnetworks, whereas the connectivity between interneuron classes was sparse. The characteristics of unitary interactions depended on the identity of both synaptic partners, whereas the short-term plasticity of synaptic transmission depended mainly on the presynaptic cell type. PV+ interneurons showed frequency-dependent depression, whereas more complex dynamics characterized the output of CCK+ interneurons. We quantitatively captured the dynamics of transmission at these different types of connection with simple mathematical models, and describe in detail the response to physiological and pathological discharge patterns. Our data suggest that the temporal propeties of PV+ interneuron transmission may contribute to sharp wave-ripple generation. These findings support the view that intrinsic and synaptic features of PV+ cells make them ideally suited for the generation of physiological network oscillations, whereas CCK+ cells implement a more subtle, graded control in the hippocampus.
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Affiliation(s)
- Z. Kohus
- Institute of Experimental MedicineHungarian Academy of SciencesBudapestHungary
- János Szentágothai, PhD Program of Semmelweis UniversityBudapestHungary
| | - S. Káli
- Institute of Experimental MedicineHungarian Academy of SciencesBudapestHungary
- Péter Pázmány Catholic UniversityFaculty of Information TechnologyBudapestHungary
| | - L. Rovira‐Esteban
- Institute of Experimental MedicineHungarian Academy of SciencesBudapestHungary
| | - D. Schlingloff
- Institute of Experimental MedicineHungarian Academy of SciencesBudapestHungary
- János Szentágothai, PhD Program of Semmelweis UniversityBudapestHungary
| | - O. Papp
- Institute of Experimental MedicineHungarian Academy of SciencesBudapestHungary
| | - T. F. Freund
- Institute of Experimental MedicineHungarian Academy of SciencesBudapestHungary
- Péter Pázmány Catholic UniversityFaculty of Information TechnologyBudapestHungary
| | - N. Hájos
- Institute of Experimental MedicineHungarian Academy of SciencesBudapestHungary
| | - A. I. Gulyás
- Institute of Experimental MedicineHungarian Academy of SciencesBudapestHungary
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32
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Colavita M, Terral G, Lemercier CE, Drago F, Marsicano G, Massa F. Layer-specific potentiation of network GABAergic inhibition in the CA1 area of the hippocampus. Sci Rep 2016; 6:28454. [PMID: 27345695 PMCID: PMC4921906 DOI: 10.1038/srep28454] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Accepted: 06/03/2016] [Indexed: 12/04/2022] Open
Abstract
One of the most important functions of GABAergic inhibition in cortical regions is the tight control of spatiotemporal activity of principal neuronal ensembles. However, electrophysiological recordings do not provide sufficient spatial information to determine the spatiotemporal properties of inhibitory plasticity. Using Voltage Sensitive Dye Imaging (VSDI) in mouse hippocampal slices, we demonstrate that GABAA-mediated field inhibitory postsynaptic potentials undergo layer-specific potentiation upon activation of metabotropic glutamate receptors (mGlu). VSDI recordings allowed detection of pharmacologically isolated GABAA-dependent hyperpolarization signals. Bath-application of the selective group-I mGlu receptor agonist, (S)-3,5-Dihydroxyphenylglycine (DHPG), induces an enhancement of the GABAergic VSDI-recorded signal, which is more or less pronounced in different hippocampal layers. This potentiation is mediated by mGlu5 and downstream activation of IP3 receptors. Our results depict network GABAergic activity in the hippocampal CA1 region and its sub-layers, showing also a novel form of inhibitory synaptic plasticity tightly coupled to glutamatergic activity.
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Affiliation(s)
- Michelangelo Colavita
- INSERM U1215, NeuroCentre Magendie, AVENIR Group "Endocannabinoids and Neuroadaptation", 33077 Bordeaux, France.,Université de Bordeaux, 33077 Bordeaux, France.,University of Catania, Biometec - Department of Biomedical and Biotechnological Sciences, 95125 Catania, Italy
| | - Geoffrey Terral
- INSERM U1215, NeuroCentre Magendie, AVENIR Group "Endocannabinoids and Neuroadaptation", 33077 Bordeaux, France.,Université de Bordeaux, 33077 Bordeaux, France
| | - Clement E Lemercier
- INSERM U1215, NeuroCentre Magendie, AVENIR Group "Endocannabinoids and Neuroadaptation", 33077 Bordeaux, France.,Université de Bordeaux, 33077 Bordeaux, France
| | - Filippo Drago
- University of Catania, Biometec - Department of Biomedical and Biotechnological Sciences, 95125 Catania, Italy
| | - Giovanni Marsicano
- INSERM U1215, NeuroCentre Magendie, AVENIR Group "Endocannabinoids and Neuroadaptation", 33077 Bordeaux, France.,Université de Bordeaux, 33077 Bordeaux, France
| | - Federico Massa
- INSERM U1215, NeuroCentre Magendie, AVENIR Group "Endocannabinoids and Neuroadaptation", 33077 Bordeaux, France.,Université de Bordeaux, 33077 Bordeaux, France
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33
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Zaletel I, Filipović D, Puškaš N. Chronic stress, hippocampus and parvalbumin-positive interneurons: what do we know so far? Rev Neurosci 2016; 27:397-409. [DOI: 10.1515/revneuro-2015-0042] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 10/26/2015] [Indexed: 02/02/2023]
Abstract
AbstractThe hippocampus is a brain structure involved in the regulation of hypothalamic-pituitary-adrenal (HPA) axis and stress response. It plays an important role in the formation of declarative, spatial and contextual memory, as well as in the processing of emotional information. As a part of the limbic system, it is a very susceptible structure towards the effects of various stressors. The molecular mechanisms of structural and functional alternations that occur in the hippocampus under chronic stress imply an increased level of circulating glucocorticoids (GCs), which is an HPA axis response to stress. Certain data show that changes induced by chronic stress may be independent from the GCs levels, opening the possibility of existence of other poorly explored mechanisms and pathways through which stressors act. The hippocampal GABAergic parvalbumin-positive (PV+) interneurons represent an especially vulnerable population of neurons in chronic stress, which may be of key importance in the development of mood disorders. However, cellular and molecular hippocampal changes that arise as a consequence of chronic stress still represent a large and unexplored area. This review discusses the current knowledge about the PV+ interneurons of the hippocampus and the influence of chronic stress on this intriguing population of neurons.
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Affiliation(s)
- Ivan Zaletel
- 1Institute of Histology and Embryology “Aleksandar Đ. Kostić”, School of Medicine, University of Belgrade, 11000 Belgrade, Serbia
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34
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Regulation of Irregular Neuronal Firing by Autaptic Transmission. Sci Rep 2016; 6:26096. [PMID: 27185280 PMCID: PMC4869121 DOI: 10.1038/srep26096] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Accepted: 04/27/2016] [Indexed: 11/08/2022] Open
Abstract
The importance of self-feedback autaptic transmission in modulating spike-time irregularity is still poorly understood. By using a biophysical model that incorporates autaptic coupling, we here show that self-innervation of neurons participates in the modulation of irregular neuronal firing, primarily by regulating the occurrence frequency of burst firing. In particular, we find that both excitatory and electrical autapses increase the occurrence of burst firing, thus reducing neuronal firing regularity. In contrast, inhibitory autapses suppress burst firing and therefore tend to improve the regularity of neuronal firing. Importantly, we show that these findings are independent of the firing properties of individual neurons, and as such can be observed for neurons operating in different modes. Our results provide an insightful mechanistic understanding of how different types of autapses shape irregular firing at the single-neuron level, and they highlight the functional importance of autaptic self-innervation in taming and modulating neurodynamics.
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35
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Hendrickson PJ, Yu GJ, Song D, Berger TW. Interactions between Inhibitory Interneurons and Excitatory Associational Circuitry in Determining Spatio-Temporal Dynamics of Hippocampal Dentate Granule Cells: A Large-Scale Computational Study. Front Syst Neurosci 2015; 9:155. [PMID: 26635545 PMCID: PMC4647071 DOI: 10.3389/fnsys.2015.00155] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Accepted: 10/27/2015] [Indexed: 11/16/2022] Open
Abstract
This paper reports on findings from a million-cell granule cell model of the rat dentate gyrus that was used to explore the contributions of local interneuronal and associational circuits to network-level activity. The model contains experimentally derived morphological parameters for granule cells, which each contain approximately 200 compartments, and biophysical parameters for granule cells, basket cells, and mossy cells that were based both on electrophysiological data and previously published models. Synaptic input to cells in the model consisted of glutamatergic AMPA-like EPSPs and GABAergic-like IPSPs from excitatory and inhibitory neurons, respectively. The main source of input to the model was from layer II entorhinal cortical neurons. Network connectivity was constrained by the topography of the system, and was derived from axonal transport studies, which provided details about the spatial spread of axonal terminal fields, as well as how subregions of the medial and lateral entorhinal cortices project to subregions of the dentate gyrus. Results of this study show that strong feedback inhibition from the basket cell population can cause high-frequency rhythmicity in granule cells, while the strength of feedforward inhibition serves to scale the total amount of granule cell activity. Results furthermore show that the topography of local interneuronal circuits can have just as strong an impact on the development of spatio-temporal clusters in the granule cell population as the perforant path topography does, both sharpening existing clusters and introducing new ones with a greater spatial extent. Finally, results show that the interactions between the inhibitory and associational loops can cause high frequency oscillations that are modulated by a low-frequency oscillatory signal. These results serve to further illustrate the importance of topographical constraints on a global signal processing feature of a neural network, while also illustrating how rich spatio-temporal and oscillatory dynamics can evolve from a relatively small number of interacting local circuits.
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Affiliation(s)
- Phillip J Hendrickson
- Department of Biomedical Engineering, University of Southern California Los Angeles, CA, USA
| | - Gene J Yu
- Department of Biomedical Engineering, University of Southern California Los Angeles, CA, USA
| | - Dong Song
- Department of Biomedical Engineering, University of Southern California Los Angeles, CA, USA
| | - Theodore W Berger
- Department of Biomedical Engineering, University of Southern California Los Angeles, CA, USA
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36
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Markram H, Muller E, Ramaswamy S, Reimann MW, Abdellah M, Sanchez CA, Ailamaki A, Alonso-Nanclares L, Antille N, Arsever S, Kahou GAA, Berger TK, Bilgili A, Buncic N, Chalimourda A, Chindemi G, Courcol JD, Delalondre F, Delattre V, Druckmann S, Dumusc R, Dynes J, Eilemann S, Gal E, Gevaert ME, Ghobril JP, Gidon A, Graham JW, Gupta A, Haenel V, Hay E, Heinis T, Hernando JB, Hines M, Kanari L, Keller D, Kenyon J, Khazen G, Kim Y, King JG, Kisvarday Z, Kumbhar P, Lasserre S, Le Bé JV, Magalhães BRC, Merchán-Pérez A, Meystre J, Morrice BR, Muller J, Muñoz-Céspedes A, Muralidhar S, Muthurasa K, Nachbaur D, Newton TH, Nolte M, Ovcharenko A, Palacios J, Pastor L, Perin R, Ranjan R, Riachi I, Rodríguez JR, Riquelme JL, Rössert C, Sfyrakis K, Shi Y, Shillcock JC, Silberberg G, Silva R, Tauheed F, Telefont M, Toledo-Rodriguez M, Tränkler T, Van Geit W, Díaz JV, Walker R, Wang Y, Zaninetta SM, DeFelipe J, Hill SL, Segev I, Schürmann F. Reconstruction and Simulation of Neocortical Microcircuitry. Cell 2015; 163:456-92. [PMID: 26451489 DOI: 10.1016/j.cell.2015.09.029] [Citation(s) in RCA: 746] [Impact Index Per Article: 82.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Revised: 05/04/2015] [Accepted: 09/11/2015] [Indexed: 02/03/2023]
Affiliation(s)
- Henry Markram
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland; Laboratory of Neural Microcircuitry, Brain Mind Institute, EPFL, 1015 Lausanne, Switzerland.
| | - Eilif Muller
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Srikanth Ramaswamy
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Michael W Reimann
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Marwan Abdellah
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Carlos Aguado Sanchez
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Anastasia Ailamaki
- Data-Intensive Applications and Systems Lab, EPFL, 1015 Lausanne, Switzerland
| | - Lidia Alonso-Nanclares
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, 28223 Madrid, Spain; Instituto Cajal (CSIC) and CIBERNED, 28002 Madrid, Spain
| | - Nicolas Antille
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Selim Arsever
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Guy Antoine Atenekeng Kahou
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Thomas K Berger
- Laboratory of Neural Microcircuitry, Brain Mind Institute, EPFL, 1015 Lausanne, Switzerland
| | - Ahmet Bilgili
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Nenad Buncic
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Athanassia Chalimourda
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Giuseppe Chindemi
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Jean-Denis Courcol
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Fabien Delalondre
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Vincent Delattre
- Laboratory of Neural Microcircuitry, Brain Mind Institute, EPFL, 1015 Lausanne, Switzerland
| | - Shaul Druckmann
- The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel; Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Raphael Dumusc
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - James Dynes
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Stefan Eilemann
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Eyal Gal
- The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Michael Emiel Gevaert
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Jean-Pierre Ghobril
- Laboratory of Neural Microcircuitry, Brain Mind Institute, EPFL, 1015 Lausanne, Switzerland
| | - Albert Gidon
- Department of Neurobiology, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Joe W Graham
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Anirudh Gupta
- Laboratory of Neural Microcircuitry, Brain Mind Institute, EPFL, 1015 Lausanne, Switzerland
| | - Valentin Haenel
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Etay Hay
- Department of Neurobiology, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel; The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Thomas Heinis
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland; Data-Intensive Applications and Systems Lab, EPFL, 1015 Lausanne, Switzerland; Imperial College London, London SW7 2AZ, UK
| | - Juan B Hernando
- CeSViMa, Centro de Supercomputación y Visualización de Madrid, Universidad Politécnica de Madrid, 28223 Madrid, Spain
| | - Michael Hines
- Department of Neurobiology, Yale University, New Haven, CT 06510 USA
| | - Lida Kanari
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Daniel Keller
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - John Kenyon
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Georges Khazen
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Yihwa Kim
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - James G King
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Zoltan Kisvarday
- MTA-Debreceni Egyetem, Neuroscience Research Group, 4032 Debrecen, Hungary
| | - Pramod Kumbhar
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Sébastien Lasserre
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland; Laboratoire d'informatique et de visualisation, EPFL, 1015 Lausanne, Switzerland
| | - Jean-Vincent Le Bé
- Laboratory of Neural Microcircuitry, Brain Mind Institute, EPFL, 1015 Lausanne, Switzerland
| | - Bruno R C Magalhães
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Angel Merchán-Pérez
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, 28223 Madrid, Spain; Instituto Cajal (CSIC) and CIBERNED, 28002 Madrid, Spain
| | - Julie Meystre
- Laboratory of Neural Microcircuitry, Brain Mind Institute, EPFL, 1015 Lausanne, Switzerland
| | - Benjamin Roy Morrice
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Jeffrey Muller
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Alberto Muñoz-Céspedes
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, 28223 Madrid, Spain; Instituto Cajal (CSIC) and CIBERNED, 28002 Madrid, Spain
| | - Shruti Muralidhar
- Laboratory of Neural Microcircuitry, Brain Mind Institute, EPFL, 1015 Lausanne, Switzerland
| | - Keerthan Muthurasa
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Daniel Nachbaur
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Taylor H Newton
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Max Nolte
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Aleksandr Ovcharenko
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Juan Palacios
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Luis Pastor
- Modeling and Virtual Reality Group, Universidad Rey Juan Carlos, 28933 Móstoles, Madrid, Spain
| | - Rodrigo Perin
- Laboratory of Neural Microcircuitry, Brain Mind Institute, EPFL, 1015 Lausanne, Switzerland
| | - Rajnish Ranjan
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland; Laboratory of Neural Microcircuitry, Brain Mind Institute, EPFL, 1015 Lausanne, Switzerland
| | - Imad Riachi
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - José-Rodrigo Rodríguez
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, 28223 Madrid, Spain; Instituto Cajal (CSIC) and CIBERNED, 28002 Madrid, Spain
| | - Juan Luis Riquelme
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Christian Rössert
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Konstantinos Sfyrakis
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Ying Shi
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland; Laboratory of Neural Microcircuitry, Brain Mind Institute, EPFL, 1015 Lausanne, Switzerland
| | - Julian C Shillcock
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Gilad Silberberg
- Department of Neuroscience, Karolinska Institutet, Stockholm 17177, Sweden
| | - Ricardo Silva
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Farhan Tauheed
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland; Data-Intensive Applications and Systems Lab, EPFL, 1015 Lausanne, Switzerland
| | - Martin Telefont
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | | | - Thomas Tränkler
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Werner Van Geit
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Jafet Villafranca Díaz
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Richard Walker
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Yun Wang
- Key Laboratory of Visual Science and National Ministry of Health, School of Optometry and Opthalmology, Wenzhou Medical College, Wenzhou 325003, China; Caritas St. Elizabeth's Medical Center, Genesys Research Institute, Tufts University, Boston, MA 02111, USA
| | - Stefano M Zaninetta
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Javier DeFelipe
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, 28223 Madrid, Spain; Instituto Cajal (CSIC) and CIBERNED, 28002 Madrid, Spain
| | - Sean L Hill
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
| | - Idan Segev
- Department of Neurobiology, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel; The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Felix Schürmann
- Blue Brain Project, École polytechnique fédérale de Lausanne (EPFL) Biotech Campus, 1202 Geneva, Switzerland
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Sanjay M, Neymotin SA, Krothapalli SB. Impaired dendritic inhibition leads to epileptic activity in a computer model of CA3. Hippocampus 2015; 25:1336-50. [PMID: 25864919 DOI: 10.1002/hipo.22440] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/10/2015] [Indexed: 01/19/2023]
Abstract
Temporal lobe epilepsy (TLE) is a common type of epilepsy with hippocampus as the usual site of origin. The CA3 subfield of hippocampus is reported to have a low epileptic threshold and hence initiates the disorder in patients with TLE. This study computationally investigates how impaired dendritic inhibition of pyramidal cells in the vulnerable CA3 subfield leads to generation of epileptic activity. A model of CA3 subfield consisting of 800 pyramidal cells, 200 basket cells (BC) and 200 Oriens-Lacunosum Moleculare (O-LM) interneurons was used. The dendritic inhibition provided by O-LM interneurons is reported to be selectively impaired in some TLEs. A step-wise approach is taken to investigate how alterations in network connectivity lead to generation of epileptic patterns. Initially, dendritic inhibition alone was reduced, followed by an increase in the external inputs received at the distal dendrites of pyramidal cells, and finally additional changes were made at the synapses between all neurons in the network. In the first case, when the dendritic inhibition of pyramidal cells alone was reduced, the local field potential activity changed from a theta-modulated gamma pattern to a prominently gamma frequency pattern. In the second case, in addition to this reduction of dendritic inhibition, with a simultaneous large increase in the external excitatory inputs received by pyramidal cells, the basket cells entered a state of depolarization block, causing the network to generate a typical ictal activity pattern. In the third case, when the dendritic inhibition onto the pyramidal cells was reduced and changes were simultaneously made in synaptic connectivity between all neurons in the network, the basket cells were again observed to enter depolarization block. In the third case, impairment of dendritic inhibition required to generate an ictal activity pattern was lesser than the two previous cases. Moreover, the ictal like activity began earlier in the third case. Hence, our study suggests that greater synaptic plasticity occurring in the whole network due to increase in reception of external excitatory inputs (due to impaired dendritic inhibition) makes the network more susceptible to generation of epileptic activity.
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Affiliation(s)
- M Sanjay
- Neurophysiology Unit, Department of Neurological Sciences, Christian Medical College, Vellore, India.,Department of Bioengineering, Christian Medical College, Vellore, India
| | - Samuel A Neymotin
- Department of Physiology and Pharmacology, State University of New York, Downstate Medical Center, Brooklyn, New York.,Department of Neurobiology, Yale University School of Medicine, New Haven, Connecticut
| | - Srinivasa B Krothapalli
- Neurophysiology Unit, Department of Neurological Sciences, Christian Medical College, Vellore, India
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Nakamura T, Matsumoto J, Takamura Y, Ishii Y, Sasahara M, Ono T, Nishijo H. Relationships among parvalbumin-immunoreactive neuron density, phase-locked gamma oscillations, and autistic/schizophrenic symptoms in PDGFR-β knock-out and control mice. PLoS One 2015; 10:e0119258. [PMID: 25803852 PMCID: PMC4372342 DOI: 10.1371/journal.pone.0119258] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2014] [Accepted: 01/09/2015] [Indexed: 12/23/2022] Open
Abstract
Cognitive deficits and negative symptoms are important therapeutic targets for schizophrenia and autism disorders. Although reduction of phase-locked gamma oscillation has been suggested to be a result of reduced parvalbumin-immunoreactive (putatively, GABAergic) neurons, no direct correlations between these have been established in these disorders. In the present study, we investigated such relationships during pharmacological treatment with a newly synthesized drug, T-817MA, which displays neuroprotective and neurotrophic effects. In this study, we used platelet-derived growth factor receptor-β gene knockout (PDGFR-β KO) mice as an animal model of schizophrenia and autism. These mutant mice display a reduction in social behaviors; deficits in prepulse inhibition (PPI); reduced levels of parvalbumin-immunoreactive neurons in the medical prefrontal cortex, hippocampus, amygdala, and superior colliculus; and a deficit in of auditory phase-locked gamma oscillations. We found that oral administration of T-817MA ameliorated all these symptoms in the PDGFR-β KO mice. Furthermore, phase-locked gamma oscillations were significantly correlated with the density of parvalbumin-immunoreactive neurons, which was, in turn, correlated with PPI and behavioral parameters. These findings suggest that recovery of parvalbumin-immunoreactive neurons by pharmacological intervention relieved the reduction of phase-locked gamma oscillations and, consequently, ameliorated PPI and social behavioral deficits. Thus, our findings suggest that phase-locked gamma oscillations could be a useful physiological biomarker for abnormality of parvalbumin-immunoreactive neurons that may induce cognitive deficits and negative symptoms of schizophrenia and autism, as well as of effective pharmacological interventions in both humans and experimental animals.
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Affiliation(s)
- Tomoya Nakamura
- System Emotional Science, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Sugitani 2630, Toyama, Japan
| | - Jumpei Matsumoto
- Department of Pathology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Sugitani 2630, Toyama, Japan
| | - Yusaku Takamura
- System Emotional Science, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Sugitani 2630, Toyama, Japan
| | - Yoko Ishii
- Department of Pathology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Sugitani 2630, Toyama, Japan
| | - Masakiyo Sasahara
- Department of Pathology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Sugitani 2630, Toyama, Japan
| | - Taketoshi Ono
- System Emotional Science, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Sugitani 2630, Toyama, Japan
| | - Hisao Nishijo
- System Emotional Science, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Sugitani 2630, Toyama, Japan
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Abstract
Replay of neuronal activity during hippocampal sharp wave-ripples (SWRs) is essential in memory formation. To understand the mechanisms underlying the initiation of irregularly occurring SWRs and the generation of periodic ripples, we selectively manipulated different components of the CA3 network in mouse hippocampal slices. We recorded EPSCs and IPSCs to examine the buildup of neuronal activity preceding SWRs and analyzed the distribution of time intervals between subsequent SWR events. Our results suggest that SWRs are initiated through a combined refractory and stochastic mechanism. SWRs initiate when firing in a set of spontaneously active pyramidal cells triggers a gradual, exponential buildup of activity in the recurrent CA3 network. We showed that this tonic excitatory envelope drives reciprocally connected parvalbumin-positive basket cells, which start ripple-frequency spiking that is phase-locked through reciprocal inhibition. The synchronized GABA(A) receptor-mediated currents give rise to a major component of the ripple-frequency oscillation in the local field potential and organize the phase-locked spiking of pyramidal cells. Optogenetic stimulation of parvalbumin-positive cells evoked full SWRs and EPSC sequences in pyramidal cells. Even with excitation blocked, tonic driving of parvalbumin-positive cells evoked ripple oscillations. Conversely, optogenetic silencing of parvalbumin-positive cells interrupted the SWRs or inhibited their occurrence. Local drug applications and modeling experiments confirmed that the activity of parvalbumin-positive perisomatic inhibitory neurons is both necessary and sufficient for ripple-frequency current and rhythm generation. These interneurons are thus essential in organizing pyramidal cell activity not only during gamma oscillation, but, in a different configuration, during SWRs.
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Varga C, Oijala M, Lish J, Szabo GG, Bezaire M, Marchionni I, Golshani P, Soltesz I. Functional fission of parvalbumin interneuron classes during fast network events. eLife 2014; 3. [PMID: 25375253 PMCID: PMC4270094 DOI: 10.7554/elife.04006] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Accepted: 11/06/2014] [Indexed: 11/22/2022] Open
Abstract
Fast spiking, parvalbumin (PV) expressing hippocampal interneurons are classified into basket, axo-axonic (chandelier), and bistratified cells. These cell classes play key roles in regulating local circuit operations and rhythmogenesis by releasing GABA in precise temporal patterns onto distinct domains of principal cells. In this study, we show that each of the three major PV cell classes further splits into functionally distinct sub-classes during fast network events in vivo. During the slower (<10 Hz) theta oscillations, each cell class exhibited its own characteristic, relatively uniform firing behavior. However, during faster (>90 Hz) oscillations, within-class differences in PV interneuron discharges emerged, which segregated along specific features of dendritic structure or somatic location. Functional divergence of PV sub-classes during fast but not slow network oscillations effectively doubles the repertoire of spatio-temporal patterns of GABA release available for rapid circuit operations. DOI:http://dx.doi.org/10.7554/eLife.04006.001 The brain continuously processes information from outside and inside the body to cope with the challenges of everyday life. As the brain carries out these processes, networks of neurons produce patterns of electrical activities called oscillations. Fast-spiking PV cells are neurons that orchestrate the precise timing of these oscillations in a region of the brain called the hippocampus, which is important for the formation of memories. PV cells perform this role by releasing a chemical called GABA that suppresses electrical activity. The hippocampus contains three distinct sub-classes of fast-spiking PV cells, but it is not clear how these different sub-classes collaborate to control the network oscillations in the hippocampus. Varga et al. have now explored this question by recording the electrical activity of PV cells in mice, while they were resting and also while they were running. PV cells are involved in both fast and slow network oscillations. As had been found in previous experiments, Varga et al. found that the three different sub-classes of PV cells behaved similarly during slow network oscillations. During fast oscillations, however, the neurons within each sub-class displayed two distinct types of behavior, depending on their shape and location. PV cells release GABA in patterns that depend on both space and time: the work of Varga et al. shows that the repertoire of patterns that can be employed by PV cells is about twice as big as was previously thought. Future studies are needed to explore the influence of this behavior on memory. DOI:http://dx.doi.org/10.7554/eLife.04006.002
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Affiliation(s)
- Csaba Varga
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, United States
| | - Mikko Oijala
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, United States
| | - Jonathan Lish
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, United States
| | - Gergely G Szabo
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, United States
| | - Marianne Bezaire
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, United States
| | - Ivan Marchionni
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, United States
| | - Peyman Golshani
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, United States
| | - Ivan Soltesz
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, United States
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Booker SA, Song J, Vida I. Whole-cell patch-clamp recordings from morphologically- and neurochemically-identified hippocampal interneurons. J Vis Exp 2014:e51706. [PMID: 25350149 DOI: 10.3791/51706] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
GABAergic inhibitory interneurons play a central role within neuronal circuits of the brain. Interneurons comprise a small subset of the neuronal population (10-20%), but show a high level of physiological, morphological, and neurochemical heterogeneity, reflecting their diverse functions. Therefore, investigation of interneurons provides important insights into the organization principles and function of neuronal circuits. This, however, requires an integrated physiological and neuroanatomical approach for the selection and identification of individual interneuron types. Whole-cell patch-clamp recording from acute brain slices of transgenic animals, expressing fluorescent proteins under the promoters of interneuron-specific markers, provides an efficient method to target and electrophysiologically characterize intrinsic and synaptic properties of specific interneuron types. Combined with intracellular dye labeling, this approach can be extended with post-hoc morphological and immunocytochemical analysis, enabling systematic identification of recorded neurons. These methods can be tailored to suit a broad range of scientific questions regarding functional properties of diverse types of cortical neurons.
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Affiliation(s)
- Sam A Booker
- Institute of Integrative Neuroanatomy, NeuroCure Cluster of Excellence, Charité Universitätmedizin
| | - Jie Song
- Institute of Integrative Neuroanatomy, NeuroCure Cluster of Excellence, Charité Universitätmedizin
| | - Imre Vida
- Institute of Integrative Neuroanatomy, NeuroCure Cluster of Excellence, Charité Universitätmedizin;
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Behavioral consequences of GABAergic neuronal diversity. Curr Opin Neurobiol 2014; 26:27-33. [DOI: 10.1016/j.conb.2013.11.002] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 10/22/2013] [Accepted: 11/06/2013] [Indexed: 11/23/2022]
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Posłuszny A. The contribution of electrical synapses to field potential oscillations in the hippocampal formation. Front Neural Circuits 2014; 8:32. [PMID: 24772068 PMCID: PMC3982077 DOI: 10.3389/fncir.2014.00032] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Accepted: 03/18/2014] [Indexed: 11/23/2022] Open
Abstract
Electrical synapses are a type of cellular membrane junction referred to as gap junctions (GJs). They provide a direct way to exchange ions between coupled cells and have been proposed as a structural basis for fast transmission of electrical potentials between neurons in the brain. For this reason GJs have been regarded as an important component within the neuronal networks that underlie synchronous neuronal activity and field potential oscillations. Initially, GJs appeared to play a particularly key role in the generation of high frequency oscillatory patterns in field potentials. In order to assess the scale of neuronal GJs contribution to field potential oscillations in the hippocampal formation, in vivo and in vitro studies are reviewed here. These investigations have shown that blocking the main neuronal GJs, those containing connexin 36 (Cx36-GJs), or knocking out the Cx36 gene affect field potential oscillatory patterns related to awake active behavior (gamma and theta rhythm) but have no effect on high frequency oscillations occurring during silent wake and sleep. Precisely how Cx36-GJs influence population activity of neurons is more complex than previously thought. Analysis of studies on the properties of transmission through GJ channels as well as Cx36-GJs functioning in pairs of coupled neurons provides some explanations of the specific influence of Cx36-GJs on field potential oscillations. It is proposed here that GJ transmission is strongly modulated by the level of neuronal network activity and changing behavioral states. Therefore, contribution of GJs to field potential oscillatory patterns depends on the behavioral state. I propose here a model, based on large body of experimental data gathered in this field by several authors, in which Cx36-GJ transmission especially contributes to oscillations related to active behavior, where it plays a role in filtering and enhancing coherent signals in the network under high-noise conditions. In contrast, oscillations related to silent wake or sleep, especially high frequency oscillations, do not require transmission by neuronal GJs. The reliability of neuronal discharges during those oscillations could be assured by conditions of higher signal-to-noise ratio and some synaptic changes taking place during active behavior.
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Affiliation(s)
- Anna Posłuszny
- Laboratory of Neuroplasticity, Department of Molecular and Cellular Neurobiology, Nencki Institute of Experimental Biology, Polish Academy of Sciences Warsaw, Poland
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Ratnadurai-Giridharan S, Stefanescu RA, Khargonekar PP, Carney PR, Talathi SS. Genesis of interictal spikes in the CA1: a computational investigation. Front Neural Circuits 2014; 8:2. [PMID: 24478636 PMCID: PMC3902301 DOI: 10.3389/fncir.2014.00002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Accepted: 01/07/2014] [Indexed: 11/13/2022] Open
Abstract
Interictal spikes (IISs) are spontaneous high amplitude, short time duration <400 ms events often observed in electroencephalographs (EEG) of epileptic patients. In vitro analysis of resected mesial temporal lobe tissue from patients with refractory temporal lobe epilepsy has revealed the presence of IIS in the CA1 subfield. In this paper, we develop a biophysically relevant network model of the CA1 subfield and investigate how changes in the network properties influence the susceptibility of CA1 to exhibit an IIS. We present a novel template based approach to identify conditions under which synchronization of paroxysmal depolarization shift (PDS) events evoked in CA1 pyramidal (Py) cells can trigger an IIS. The results from this analysis are used to identify the synaptic parameters of a minimal network model that is capable of generating PDS in response to afferent synaptic input. The minimal network model parameters are then incorporated into a detailed network model of the CA1 subfield in order to address the following questions: (1) How does the formation of an IIS in the CA1 depend on the degree of sprouting (recurrent connections) between the CA1 Py cells and the fraction of CA3 Shaffer collateral (SC) connections onto the CA1 Py cells? and (2) Is synchronous afferent input from the SC essential for the CA1 to exhibit IIS? Our results suggest that the CA1 subfield with low recurrent connectivity (absence of sprouting), mimicking the topology of a normal brain, has a very low probability of producing an IIS except when a large fraction of CA1 neurons (>80%) receives a barrage of quasi-synchronous afferent input (input occurring within a temporal window of ≤24 ms) via the SC. However, as we increase the recurrent connectivity of the CA1 (Psprout > 40); mimicking sprouting in a pathological CA1 network, the CA1 can exhibit IIS even in the absence of a barrage of quasi-synchronous afferents from the SC (input occurring within temporal window >80 ms) and a low fraction of CA1 Py cells (≈30%) receiving SC input. Furthermore, we find that in the presence of Poisson distributed random input via SC, the CA1 network is able to generate spontaneous periodic IISs (≈3 Hz) for high degrees of recurrent Py connectivity (Psprout > 70). We investigate the conditions necessary for this phenomenon and find that spontaneous IISs closely depend on the degree of the network's intrinsic excitability.
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Affiliation(s)
| | - Roxana A Stefanescu
- Department of Otolaryngology, Kresge Hearing Research Institute, University of Michigan Ann Arbor, MI, USA
| | | | - Paul R Carney
- J Crayton Pruitt Family Department of Biomedical Engineering, University of Florida Gainesville, FL, USA ; Department of Pediatrics, University of Florida Gainesville, FL, USA
| | - Sachin S Talathi
- J Crayton Pruitt Family Department of Biomedical Engineering, University of Florida Gainesville, FL, USA ; Department of Pediatrics, University of Florida Gainesville, FL, USA ; Qualcomm Corp R&D San Diego, CA, USA
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45
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Deleuze C, Pazienti A, Bacci A. Autaptic self-inhibition of cortical GABAergic neurons: synaptic narcissism or useful introspection? Curr Opin Neurobiol 2014; 26:64-71. [PMID: 24434607 DOI: 10.1016/j.conb.2013.12.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Revised: 12/09/2013] [Accepted: 12/17/2013] [Indexed: 12/11/2022]
Abstract
Fast synaptic inhibition sculpts all forms of cortical activity by means of a specialized connectivity pattern between highly heterogeneous inhibitory interneurons and principal excitatory cells. Importantly, inhibitory neurons connect also to each other extensively, following a detailed blueprint, and, indeed, specific forms of disinhibition affect important behavioral functions. Here we discuss a peculiar form of cortical disinhibition: the massive autaptic self-inhibition of parvalbumin-(PV) positive basket cells. Despite being described long ago, autaptic inhibition onto PV basket cells is rarely included in cortical circuit diagrams, perhaps because of its still elusive function. We propose here a potential dual role of autaptic feedback inhibition in temporally coordinating PV basket cells during cortical network activity.
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Affiliation(s)
- Charlotte Deleuze
- ICM - Institut du Cerveau et de la Moelle épinière, Groupe Hospitalier Pitié Salpêtrière, 47 Boulevard de l'Hopital, 75013 Paris, France
| | | | - Alberto Bacci
- ICM - Institut du Cerveau et de la Moelle épinière, Groupe Hospitalier Pitié Salpêtrière, 47 Boulevard de l'Hopital, 75013 Paris, France; Centre National de la Recherche Scientifique Unité Mixte de Recherche 7225, Institut National de la Santé et de la Recherche Médicale Unité Mixte de Recherche 975, Université Pierre et Marie Curie - Paris 6, 75005 Paris, France.
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46
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Packer AM, McConnell DJ, Fino E, Yuste R. Axo-dendritic overlap and laminar projection can explain interneuron connectivity to pyramidal cells. Cereb Cortex 2013; 23:2790-802. [PMID: 22941716 PMCID: PMC3968298 DOI: 10.1093/cercor/bhs210] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Neocortical GABAergic interneurons have important roles in the normal and pathological states of the circuit. Recent work has revealed that somatostatin-positive (SOM) and parvalbumin-positive (PV) interneurons connect promiscuously to pyramidal cells (PCs). We investigated whether Peters' rule, that is, the spatial overlap of axons and dendrites, could explain this unspecific connectivity. We reconstructed the morphologies of P11-17 mouse SOM and PV interneurons and their PC targets, and performed Monte Carlo simulations to build maps of predicted connectivity based on Peters' rule. We then compared the predicted with the real connectivity maps, measured with 2-photon uncaging experiments, and found no statistical differences between them in the probability of connection as a function of distance and in the spatial structure of the maps. Finally, using reconstructions of connected SOM-PCs and PV-PCs, we investigated the subcellular targeting specificity, by analyzing the postsynaptic position of the contacts, and found that their spatial distributions match the distribution of postsynaptic PC surface area, in agreement with Peters' rule. Thus, the spatial profile of the connectivity maps and even the postsynaptic position of interneuron contacts could result from the mere overlap of axonal and dendritic arborizations and their laminar projections patterns.
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Affiliation(s)
- Adam M Packer
- HHMI, Department of Biological Sciences, Columbia University, New York, NY 10027, USA
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Bezaire MJ, Soltesz I. Quantitative assessment of CA1 local circuits: knowledge base for interneuron-pyramidal cell connectivity. Hippocampus 2013; 23:751-85. [PMID: 23674373 DOI: 10.1002/hipo.22141] [Citation(s) in RCA: 224] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Revised: 04/25/2013] [Accepted: 04/26/2013] [Indexed: 12/17/2022]
Abstract
In this work, through a detailed literature review, data-mining, and extensive calculations, we provide a current, quantitative estimate of the cellular and synaptic constituents of the CA1 region of the rat hippocampus. Beyond estimating the cell numbers of GABAergic interneuron types, we calculate their convergence onto CA1 pyramidal cells and compare it with the known input synapses on CA1 pyramidal cells. The convergence calculation and comparison are also made for excitatory inputs to CA1 pyramidal cells. In addition, we provide a summary of the excitatory and inhibitory convergence onto interneurons. The quantitative knowledge base assembled and synthesized here forms the basis for data-driven, large-scale computational modeling efforts. Additionally, this work highlights specific instances where the available data are incomplete, which should inspire targeted experimental projects toward a more complete quantification of the CA1 neurons and their connectivity.
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Affiliation(s)
- Marianne J Bezaire
- Department of Anatomy and Neurobiology, University of California, Irvine, California
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Distinct dendritic arborization and in vivo firing patterns of parvalbumin-expressing basket cells in the hippocampal area CA3. J Neurosci 2013; 33:6809-25. [PMID: 23595740 DOI: 10.1523/jneurosci.5052-12.2013] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Hippocampal CA3 area generates temporally structured network activity such as sharp waves and gamma and theta oscillations. Parvalbumin-expressing basket cells, making GABAergic synapses onto cell bodies and proximal dendrites of pyramidal cells, control pyramidal cell activity and participate in network oscillations in slice preparations, but their roles in vivo remain to be tested. We have recorded the spike timing of parvalbumin-expressing basket cells in areas CA2/3 of anesthetized rats in relation to CA3 putative pyramidal cell firing and activity locally and in area CA1. During theta oscillations, CA2/3 basket cells fired on the same phase as putative pyramidal cells, but, surprisingly, significantly later than downstream CA1 basket cells. This indicates a distinct modulation of CA3 and CA1 pyramidal cells by basket cells, which receive different inputs. We observed unexpectedly large dendritic arborization of CA2/3 basket cells in stratum lacunosum moleculare (33% of length, 29% surface, and 24% synaptic input from a total of ∼35,000), different from the dendritic arborizations of CA1 basket cells. Area CA2/3 basket cells fired phase locked to both CA2/3 and CA1 gamma oscillations, and increased firing during CA1 sharp waves, thus supporting the role of CA3 networks in the generation of gamma oscillations and sharp waves. However, during ripples associated with sharp waves, firing of CA2/3 basket cells was phase locked only to local but not CA1 ripples, suggesting the independent generation of fast oscillations by basket cells in CA1 and CA2/3. The distinct spike timing of basket cells during oscillations in CA1 and CA2/3 suggests differences in synaptic inputs paralleled by differences in dendritic arborizations.
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Chamberland S, Topolnik L. Inhibitory control of hippocampal inhibitory neurons. Front Neurosci 2012; 6:165. [PMID: 23162426 PMCID: PMC3496901 DOI: 10.3389/fnins.2012.00165] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Accepted: 10/24/2012] [Indexed: 11/13/2022] Open
Abstract
Information processing within neuronal networks is determined by a dynamic partnership between principal neurons and local circuit inhibitory interneurons. The population of GABAergic interneurons is extremely heterogeneous and comprises, in many brain regions, cells with divergent morphological and physiological properties, distinct molecular expression profiles, and highly specialized functions. GABAergic interneurons have been studied extensively during the past two decades, especially in the hippocampus, which is a relatively simple cortical structure. Different types of hippocampal inhibitory interneurons control spike initiation [e.g., axo-axonic and basket cells (BCs)] and synaptic integration (e.g., bistratified and oriens–lacunosum moleculare interneurons) within pyramidal neurons and synchronize local network activity, providing a means for functional segregation of neuronal ensembles and proper routing of hippocampal information. Thus, it is thought that, at least in the hippocampus, GABAergic inhibitory interneurons represent critical regulating elements at all stages of information processing, from synaptic integration and spike generation to large-scale network activity. However, this raises an important question: if inhibitory interneurons are fundamental for network computations, what are the mechanisms that control the activity of the interneurons themselves? Given the essential role of synaptic inhibition in the regulation of neuronal activity, it would be logical to expect that specific inhibitory mechanisms have evolved to control the operation of interneurons. Here, we review the mechanisms of synaptic inhibition of interneurons and discuss their role in the operation of hippocampal inhibitory circuits.
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Affiliation(s)
- Simon Chamberland
- Axis of Cellular and Molecular Neuroscience, IUSMQ, Department of Biochemistry, Microbiology and Bio-informatics, Université Laval Québec, QC, Canada
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Regulation of neuronal input transformations by tunable dendritic inhibition. Nat Neurosci 2012; 15:423-30, S1-3. [PMID: 22246433 DOI: 10.1038/nn.3024] [Citation(s) in RCA: 314] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Accepted: 12/07/2011] [Indexed: 11/08/2022]
Abstract
Transforming synaptic input into action potential output is a fundamental function of neurons. The pattern of action potential output from principal cells of the mammalian hippocampus encodes spatial and nonspatial information, but the cellular and circuit mechanisms by which neurons transform their synaptic input into a given output are unknown. Using a combination of optical activation and cell type-specific pharmacogenetic silencing in vitro, we found that dendritic inhibition is the primary regulator of input-output transformations in mouse hippocampal CA1 pyramidal cells, and acts by gating the dendritic electrogenesis driving burst spiking. Dendrite-targeting interneurons are themselves modulated by interneurons targeting pyramidal cell somata, providing a synaptic substrate for tuning pyramidal cell output through interactions in the local inhibitory network. These results provide evidence for a division of labor in cortical circuits, where distinct computational functions are implemented by subtypes of local inhibitory neurons.
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