1
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Ponzi A, Dura-Bernal S, Migliore M. Theta-gamma phase amplitude coupling in a hippocampal CA1 microcircuit. PLoS Comput Biol 2023; 19:e1010942. [PMID: 36952558 PMCID: PMC10072417 DOI: 10.1371/journal.pcbi.1010942] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 04/04/2023] [Accepted: 02/13/2023] [Indexed: 03/25/2023] Open
Abstract
Phase amplitude coupling (PAC) between slow and fast oscillations is found throughout the brain and plays important functional roles. Its neural origin remains unclear. Experimental findings are often puzzling and sometimes contradictory. Most computational models rely on pairs of pacemaker neurons or neural populations tuned at different frequencies to produce PAC. Here, using a data-driven model of a hippocampal microcircuit, we demonstrate that PAC can naturally emerge from a single feedback mechanism involving an inhibitory and excitatory neuron population, which interplay to generate theta frequency periodic bursts of higher frequency gamma. The model suggests the conditions under which a CA1 microcircuit can operate to elicit theta-gamma PAC, and highlights the modulatory role of OLM and PVBC cells, recurrent connectivity, and short term synaptic plasticity. Surprisingly, the results suggest the experimentally testable prediction that the generation of the slow population oscillation requires the fast one and cannot occur without it.
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Affiliation(s)
- Adam Ponzi
- Institute of Biophysics, National Research Council, Palermo, Italy
| | - Salvador Dura-Bernal
- Department of Physiology and Pharmacology, SUNY Downstate Health Sciences University, Brooklyn, New York, United States of America
| | - Michele Migliore
- Institute of Biophysics, National Research Council, Palermo, Italy
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2
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Wang YL, Wang JG, Guo S, Guo FL, Liu EJ, Yang X, Feng B, Wang JZ, Vreugdenhil M, Lu CB. Oligomeric β-Amyloid Suppresses Hippocampal γ-Oscillations through Activation of the mTOR/S6K1 Pathway. Aging Dis 2023:AD.2023.0123. [PMID: 37163441 PMCID: PMC10389838 DOI: 10.14336/ad.2023.0123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Accepted: 01/23/2023] [Indexed: 05/12/2023] Open
Abstract
Neuronal synchronization at gamma frequency (30-100 Hz: γ) is impaired in early-stage Alzheimer's disease (AD) patients and AD models. Oligomeric Aβ1-42 caused a concentration-dependent reduction of γ-oscillation strength and regularity while increasing its frequency. The mTOR1 inhibitor rapamycin prevented the Aβ1-42-induced suppression of γ-oscillations, whereas the mTOR activator leucine mimicked the Aβ1-42-induced suppression. Activation of the downstream kinase S6K1, but not inhibition of eIF4E, was required for the Aβ1-42-induced suppression. The involvement of the mTOR/S6K1 signaling in the Aβ1-42-induced suppression was confirmed in Aβ-overexpressing APP/PS1 mice, where inhibiting mTOR or S6K1 restored degraded γ-oscillations. To assess the network changes that may underlie the mTOR/S6K1 mediated γ-oscillation impairment in AD, we tested the effect of Aβ1-42 on IPSCs and EPSCs recorded in pyramidal neurons. Aβ1-42 reduced EPSC amplitude and frequency and IPSC frequency, which could be prevented by inhibiting mTOR or S6K1. These experiments indicate that in early AD, oligomer Aβ1-42 impairs γ-oscillations by reducing inhibitory interneuron activity by activating the mTOR/S6K1 signaling pathway, which may contribute to early cognitive decline and provides new therapeutic targets.
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Affiliation(s)
- Ya-Li Wang
- Department of Physiology and Pathophysiology, Henan International Joint Laboratory of Non-Invasive Neuromodulation, Xinxiang Medical University, Xinxiang, China
| | - Jian-Gang Wang
- Department of Physiology and Pathophysiology, Henan International Joint Laboratory of Non-Invasive Neuromodulation, Xinxiang Medical University, Xinxiang, China
| | - Shuling Guo
- Department of Cardiovascular Medicine, Luminghu District, Xuchang Central Hospital, Xuchang, China
| | - Fang-Li Guo
- Department of Neurology, Anyang District Hospital of Puyang City, Anyang, China
| | - En-Jie Liu
- Department of Pathology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Xin Yang
- Key Laboratory of Translational Research for Brain Diseases, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Bingyan Feng
- Department of Physiology and Pathophysiology, Henan International Joint Laboratory of Non-Invasive Neuromodulation, Xinxiang Medical University, Xinxiang, China
| | - Jian-Zhi Wang
- Department of Pathophysiology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Key Laboratory of Ministry of Education of China for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Martin Vreugdenhil
- Department of Life Sciences, Birmingham City University, Birmingham, UK
- Department of Psychology, Xinxiang Medical University, Xinxiang, China
| | - Cheng-Biao Lu
- Department of Physiology and Pathophysiology, Henan International Joint Laboratory of Non-Invasive Neuromodulation, Xinxiang Medical University, Xinxiang, China
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3
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The Control of Rat Hippocampal Gamma Oscillation Strength by BK Channel Activity. Neuroscience 2021; 475:220-228. [PMID: 34509547 DOI: 10.1016/j.neuroscience.2021.09.002] [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: 03/04/2021] [Revised: 09/01/2021] [Accepted: 09/02/2021] [Indexed: 11/20/2022]
Abstract
Neuronal network oscillations in the gamma frequency band (30-80 Hz, γ oscillations) are associated with the higher brain functions such as perception, attention, learning and memory. BK channels mediate rapid repolarization and fast afterhyperpolarization in neurons and control neuronal excitability, and potentially control hippocampal γ oscillations. In this study, we examined the effects of modulating BK channels on hippocampal γ oscillations in the absence or presence of Ca2+ influx through voltage-gated Ca2+ channels (VGCC) or Ca2+-permeable AMPA receptors (CP-AMPAR). We found that blocking BK channels enhanced γ power, without affecting oscillation frequency or regularity, suggesting that BK channel activity suppresses γ oscillations. Blocking either VGCC or CP-AMPAR itself enhanced γ power, and completely occluded the effect of BK channel blockers on γ oscillations, whereas blocking BK channels first could not prevent a further γ power increase upon blockade of either CP-AMPAR or VGCC. We propose that Ca2+ influx through VGCC or CP-AMPAR during γ oscillations, cause membrane BK channel activation and regulate hippocampal γ oscillation strength by negative feedback.
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4
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Amemiya S, Redish AD. Hippocampal Theta-Gamma Coupling Reflects State-Dependent Information Processing in Decision Making. Cell Rep 2019; 22:3328-3338. [PMID: 29562187 PMCID: PMC5929482 DOI: 10.1016/j.celrep.2018.02.091] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Revised: 01/22/2018] [Accepted: 01/23/2018] [Indexed: 11/11/2022] Open
Abstract
During decision making, hippocampal activity encodes information sometimes about present and sometimes about potential future plans. The mechanisms underlying this transition remain unknown. Building on the evidence that gamma oscillations at different frequencies (low gamma [LG], 30–55 Hz; high gamma [HG], 60–90 Hz; and epsilon, 100–140 Hz) reflect inputs from different circuits, we identified how changes in those frequencies reflect different information-processing states. Using a unique noradrenergic manipulation by clonidine, which shifted both neural representations and gamma states, we found that future representations depended on gamma components. These changes were identifiable on each cycle of theta as asymmetries in the theta cycle, which arose from changes within the ratio of LG and HG power and the underlying phases of those gamma rhythms within the theta cycle. These changes in asymmetry of the theta cycle reflected changes in representations of present and future on each theta cycle.
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Affiliation(s)
- Seiichiro Amemiya
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA
| | - A David Redish
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA.
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5
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Masri RA, Lee SCS, Madigan MC, Grünert U. Particle-Mediated Gene Transfection and Organotypic Culture of Postmortem Human Retina. Transl Vis Sci Technol 2019; 8:7. [PMID: 30941264 PMCID: PMC6438245 DOI: 10.1167/tvst.8.2.7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 01/07/2019] [Indexed: 12/25/2022] Open
Abstract
Purpose Particle-mediated gene transfer has been used in animal models to study the morphology and connectivity of retinal ganglion cells. The aim of the present study was to apply this method to transfect ganglion cells in postmortem human retina. Methods Postmortem human eyes from male and female donors aged 40 to 76 years old were obtained within 15 hours after death. In addition, two marmoset retinas were obtained immediately after death. Ganglion cells were transfected with an expression plasmid for the postsynaptic density 95 protein conjugated to green or yellow fluorescent protein. Retinas were cultured for 3 days, fixed and then processed with immunohistochemical markers to reveal their stratification in the inner plexiform layer. Results The retinas maintained their morphology and immunohistochemical properties for at least 3 days in culture. Bipolar and ganglion cell morphology was comparable to that observed in noncultured tissue. The quality of transfected cells in human retina was similar to that in freshly enucleated marmoset eyes. Based on dendritic field size and stratification, at least 11 morphological types of retinal ganglion cell were distinguished. Conclusions Particle-mediated gene transfer allows efficient targeting of retinal ganglion cells in cultured postmortem human retina. Translational Relevance The translational value of this methodology lies in the provision of an in vitro platform to study structural and connectivity changes in human eye diseases that affect the integrity and organization of cells in the retina.
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Affiliation(s)
- Rania A Masri
- The University of Sydney, Faculty of Medicine and Health, Save Sight Institute and Discipline of Ophthalmology, Sydney, Australia.,Australian Research Council Centre of Excellence for Integrative Brain Function, Sydney Node, The University of Sydney, Sydney, Australia
| | - Sammy C S Lee
- The University of Sydney, Faculty of Medicine and Health, Save Sight Institute and Discipline of Ophthalmology, Sydney, Australia.,Australian Research Council Centre of Excellence for Integrative Brain Function, Sydney Node, The University of Sydney, Sydney, Australia
| | - Michele C Madigan
- The University of Sydney, Faculty of Medicine and Health, Save Sight Institute and Discipline of Ophthalmology, Sydney, Australia.,School of Optometry and Vision Science, University of New South Wales, Sydney, Australia
| | - Ulrike Grünert
- The University of Sydney, Faculty of Medicine and Health, Save Sight Institute and Discipline of Ophthalmology, Sydney, Australia.,Australian Research Council Centre of Excellence for Integrative Brain Function, Sydney Node, The University of Sydney, Sydney, Australia
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6
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Zhang Y, Ahmed S, Neagu G, Wang Y, Li Z, Wen J, Liu C, Vreugdenhil M. μ-Opioid receptor activation modulates CA3-to-CA1 gamma oscillation phase-coupling. IBRO Rep 2019; 6:122-131. [PMID: 30834352 PMCID: PMC6384309 DOI: 10.1016/j.ibror.2019.01.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 01/07/2019] [Indexed: 12/03/2022] Open
Abstract
CA3 gamma oscillation (γ) drives CA1 gamma and suppresses CA1 intrinsic fast γ. μ-opioid receptor (MOR) activation reduces γ frequency in CA3 and CA1. MOR activation in CA1 phase-uncouples CA1 γ from CA3 γ. Uncoupling is not due to CA3 γ deceleration by MOR activation.
In the intact brain, hippocampal area CA1 alternates between low-frequency gamma oscillations (γ), phase-locked to low-frequency γ in CA3, and high-frequency γ, phase-locked to γ in the medial entorhinal cortex. In hippocampal slices, γ in CA1 is phase-locked to CA3 low-frequency γ. However, when Schaffer collaterals are cut, CA1 can generate its own high-frequency γ. Here we test whether (un)coupling of CA1 γ from CA3 γ can be caused by μ-opioid receptor (MOR) modulation. In CA1 minislices isolated from rat ventral hippocampus slices, MOR activation by DAMGO reduced the dominant frequency of intrinsic fast γ, induced by carbachol. In intact slices, DAMGO strongly reduced the dominant frequency of CA3 slow γ, but did not affect γ power consistently. DAMGO suppressed the phase coupling of CA1 γ to CA3 slow γ and increased the power of CA1 intrinsic fast γ, but not in the presence of the MOR antagonist CTAP. The benzodiazepine zolpidem and local application of DAMGO to CA3 both mimicked the reduction in dominant frequency of CA3 slow γ, but did not reduce the phase coupling. Local application of DAMGO to CA1 reduced phase coupling. These results suggest that MOR-expressing CA1 interneurons, feed-forwardly activated by Schaffer collaterals, are responsible for the phase coupling between CA3 γ and CA1 γ. Modulating their activity may switch the CA1 network between low-frequency γ and high-frequency γ, controlling the information flow between CA1 and CA3 or medial entorhinal cortex respectively.
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Key Words
- CA1, Cornu ammonis area 1
- CA3, Cornu ammonis area 3
- CTAP, D-Phe-Cys-Tyr-D-Trp-Arg-Thr-Pen-Thr-NH2
- DAMGO, [D-Ala2, NMe-Phe4, Gly-ol5]-enkephalin
- EPSC, Excitatory post-synaptic current
- ERP, Event-related potential
- Gamma
- Hippocampus
- IPSC, Inhibitory post-synaptic current
- Interneuron
- MEC, Medial entorhinal cortex
- MOR, μ opioid receptor
- Oscillation
- PING, pyramidal-interneuron-network gamma
- PLV, phase-locking value
- PV+, parvalbumin-expressing
- Phase-coupling
- TTX, tetrodotoxin
- aCSF, artificial cerebrospinal fluid
- s.e.m., Standard error of the mean
- γ, gamma frequency oscillation
- θ, theta frequency oscillation
- μ-Opioid
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Affiliation(s)
- Yujiao Zhang
- Department of Psychology, Xinxiang Medical University, Jinsui Avenue, Xinxiang, 453003, PR China
| | - Sanya Ahmed
- Department of Neuroscience, College of Medical and Dental Sciences, University of Birmingham, Vincent Drive, Birmingham, B15 2TT, United Kingdom
| | - Georgiana Neagu
- Department of Neuroscience, College of Medical and Dental Sciences, University of Birmingham, Vincent Drive, Birmingham, B15 2TT, United Kingdom
| | - Yali Wang
- Department of Neurobiology, Xinxiang Medical University, Jinsui Avenue, Xinxiang, 453003, PR China
| | - Zhenyi Li
- Department of Psychology, Xinxiang Medical University, Jinsui Avenue, Xinxiang, 453003, PR China
| | - Jianbin Wen
- Department of Neurobiology, Xinxiang Medical University, Jinsui Avenue, Xinxiang, 453003, PR China
| | - Chunjie Liu
- Department of Psychology, Xinxiang Medical University, Jinsui Avenue, Xinxiang, 453003, PR China
| | - Martin Vreugdenhil
- Department of Psychology, Xinxiang Medical University, Jinsui Avenue, Xinxiang, 453003, PR China.,Department of Neuroscience, College of Medical and Dental Sciences, University of Birmingham, Vincent Drive, Birmingham, B15 2TT, United Kingdom.,Department of Life Science, School of Health Sciences, Birmingham City University, Westbourne Road, Birmingham, B15 3TN, United Kingdom
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7
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Skovgård K, Agerskov C, Kohlmeier KA, Herrik KF. The 5-HT3 receptor antagonist ondansetron potentiates the effects of the acetylcholinesterase inhibitor donepezil on neuronal network oscillations in the rat dorsal hippocampus. Neuropharmacology 2018; 143:130-142. [DOI: 10.1016/j.neuropharm.2018.09.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 09/07/2018] [Accepted: 09/11/2018] [Indexed: 11/24/2022]
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8
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Restoring wild-type-like CA1 network dynamics and behavior during adulthood in a mouse model of schizophrenia. Nat Neurosci 2018; 21:1412-1420. [PMID: 30224804 DOI: 10.1038/s41593-018-0225-y] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 07/12/2018] [Indexed: 01/16/2023]
Abstract
Schizophrenia is a severely debilitating neurodevelopmental disorder. Establishing a causal link between circuit dysfunction and particular behavioral traits that are relevant to schizophrenia is crucial to shed new light on the mechanisms underlying the pathology. We studied an animal model of the human 22q11 deletion syndrome, the mutation that represents the highest genetic risk of developing schizophrenia. We observed a desynchronization of hippocampal neuronal assemblies that resulted from parvalbumin interneuron hypoexcitability. Rescuing parvalbumin interneuron excitability with pharmacological or chemogenetic approaches was sufficient to restore wild-type-like CA1 network dynamics and hippocampal-dependent behavior during adulthood. In conclusion, our data provide insights into the network dysfunction underlying schizophrenia and highlight the use of reverse engineering to restore physiological and behavioral phenotypes in an animal model of neurodevelopmental disorder.
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9
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Reyes-Garcia SZ, Scorza CA, Araújo NS, Ortiz-Villatoro NN, Jardim AP, Centeno R, Yacubian EMT, Faber J, Cavalheiro EA. Different patterns of epileptiform-like activity are generated in the sclerotic hippocampus from patients with drug-resistant temporal lobe epilepsy. Sci Rep 2018; 8:7116. [PMID: 29740014 PMCID: PMC5940759 DOI: 10.1038/s41598-018-25378-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Accepted: 04/19/2018] [Indexed: 12/26/2022] Open
Abstract
Human hippocampal slice preparations from patients with temporal lobe epilepsy (TLE) associated with hippocampal sclerosis (HS) are excellent material for the characterization of epileptiform-like activity. However, it is still unknown if hippocampal regions as cornu Ammonis (CA) 1, CA3 and CA4, generate population epileptiform-like activity. Here, we investigated epileptiform activities of the subiculum, CA1, CA2, CA3, CA4 (induced by elevation of extracellular potassium concentration) and the dentate gyrus (induced with hilar stimulation and elevation of potassium concentration) from sclerotic hippocampi of patients with drug-resistant TLE. Five types of epileptiform-like activity were observed: interictal-like events; periodic ictal spiking; seizure-like events; spreading depression-like events; tonic seizure-like events and no activity. Different susceptibilities to generate epileptiform activity among hippocampal regions were observed; the dentate gyrus was the most susceptible region followed by the subiculum, CA4, CA1, CA2 and CA3. The incidence of epileptiform activity pattern was associated with specific regions of the hippocampal formation. Moreover, it was observed that each region of the hippocampal formation exhibits frequency-specific ranges in each subfield of the sclerotic human tissue. In conclusion, this study demonstrates that epileptiform-like activity may be induced in different regions of the hippocampal formation, including regions that are severely affected by neuronal loss.
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Affiliation(s)
- Selvin Z Reyes-Garcia
- Departamento de Neurologia e Neurocirurgia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil. .,Departamento de Ciencias Morfológicas, Facultad de Ciencias Médicas, Universidad Nacional Autónoma de Honduras, Tegucigalpa, Honduras.
| | - Carla A Scorza
- Departamento de Neurologia e Neurocirurgia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Noemi S Araújo
- Departamento de Neurologia e Neurocirurgia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Nancy N Ortiz-Villatoro
- Departamento de Neurologia e Neurocirurgia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Anaclara Prada Jardim
- Departamento de Neurologia e Neurocirurgia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Ricardo Centeno
- Departamento de Neurologia e Neurocirurgia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Elza Márcia Targas Yacubian
- Departamento de Neurologia e Neurocirurgia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Jean Faber
- Departamento de Neurologia e Neurocirurgia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Esper A Cavalheiro
- Departamento de Neurologia e Neurocirurgia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
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10
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Butler JL, Hay YA, Paulsen O. Comparison of three gamma oscillations in the mouse entorhinal-hippocampal system. Eur J Neurosci 2018; 48:2795-2806. [PMID: 29356162 PMCID: PMC6221063 DOI: 10.1111/ejn.13831] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 11/29/2017] [Accepted: 01/08/2018] [Indexed: 02/01/2023]
Abstract
The entorhinal-hippocampal system is an important circuit in the brain, essential for certain cognitive tasks such as memory and navigation. Different gamma oscillations occur in this circuit, with the medial entorhinal cortex (mEC), CA3 and CA1 all generating gamma oscillations with different properties. These three gamma oscillations converge within CA1, where much work has gone into trying to isolate them from each other. Here, we compared the gamma generators in the mEC, CA3 and CA1 using optogenetically induced theta-gamma oscillations. Expressing channelrhodopsin-2 in principal neurons in each of the three regions allowed for the induction of gamma oscillations via sinusoidal blue light stimulation at theta frequency. Recording the oscillations in CA1 in vivo, we found that CA3 stimulation induced slower gamma oscillations than CA1 stimulation, matching in vivo reports of spontaneous CA3 and CA1 gamma oscillations. In brain slices ex vivo, optogenetic stimulation of CA3 induced slower gamma oscillations than stimulation of either mEC or CA1, whose gamma oscillations were of similar frequency. All three gamma oscillations had a current sink-source pair between the perisomatic and dendritic layers of the same region. Taking advantage of this model to analyse gamma frequency mechanisms in slice, we showed using pharmacology that all three gamma oscillations were dependent on the same types of synaptic receptor, being abolished by blockade of either type A γ-aminobutyric acid receptors or α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid/kainate receptors, and insensitive to blockade of N-methyl-d-aspartate receptors. These results indicate that a fast excitatory-inhibitory feedback loop underlies the generation of gamma oscillations in all three regions.
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Affiliation(s)
- James L Butler
- Physiological Laboratory, Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK
| | - Y Audrey Hay
- Physiological Laboratory, Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK
| | - Ole Paulsen
- Physiological Laboratory, Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK
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11
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Dheerendra P, Lynch NM, Crutwell J, Cunningham MO, Smulders TV. In vitro characterization of gamma oscillations in the hippocampal formation of the domestic chick. Eur J Neurosci 2018; 48:2807-2815. [PMID: 29120510 PMCID: PMC6220815 DOI: 10.1111/ejn.13773] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 10/28/2017] [Accepted: 11/02/2017] [Indexed: 11/30/2022]
Abstract
Avian and mammalian brains have evolved independently from each other for about 300 million years. During that time, the hippocampal formation (HF) has diverged in morphology and cytoarchitecture, but seems to have conserved much of its function. It is therefore an open question how seemingly different neural organizations can generate the same function. A prominent feature of the mammalian hippocampus is that it generates different neural oscillations, including the gamma rhythm, which plays an important role in memory processing. In this study, we investigate whether the avian hippocampus also generates gamma oscillations, and whether similar pharmacological mechanisms are involved in this function. We investigated the existence of gamma oscillations in avian HF using in vitro electrophysiology in P0–P12 domestic chick (Gallus gallus domesticus) HF brain slices. Persistent gamma frequency oscillations were induced by the bath application of the cholinergic agonist carbachol, but not by kainate, a glutamate receptor agonist. Similar to other species, carbachol‐evoked gamma oscillations were sensitive to GABAA, AMPA/kainate and muscarinic (M1) receptor antagonism. Therefore, similar to mammalian species, muscarinic receptor‐activated avian HF gamma oscillations may arise via a pyramidal‐interneuron gamma (PING)‐based mechanism. Gamma oscillations are most prominent in the ventromedial area of the hippocampal slices, and gamma power is reduced more laterally and dorsally in the HF. We conclude that similar micro‐circuitry may exist in the avian and mammalian hippocampal formation, and this is likely to relate to the shared function of the two structures.
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Affiliation(s)
- Pradeep Dheerendra
- Institute of Neuroscience, Newcastle University, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK
| | - Nicholas M Lynch
- Institute of Neuroscience, Newcastle University, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK.,University of Louisville, Louisville, KY, USA
| | - Joseph Crutwell
- Institute of Neuroscience, Newcastle University, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK
| | - Mark O Cunningham
- Institute of Neuroscience, Newcastle University, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK
| | - Tom V Smulders
- Institute of Neuroscience, Newcastle University, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK.,Centre for Behaviour and Evolution, Newcastle University, Newcastle upon Tyne, UK
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12
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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: 495] [Impact Index Per Article: 70.7] [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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13
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Amat-Foraster M, Leiser SC, Herrik KF, Richard N, Agerskov C, Bundgaard C, Bastlund JF, de Jong IE. The 5-HT6 receptor antagonist idalopirdine potentiates the effects of donepezil on gamma oscillations in the frontal cortex of anesthetized and awake rats without affecting sleep-wake architecture. Neuropharmacology 2017; 113:45-59. [DOI: 10.1016/j.neuropharm.2016.09.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 08/14/2016] [Accepted: 09/15/2016] [Indexed: 01/21/2023]
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Intrinsic Cornu Ammonis Area 1 Theta-Nested Gamma Oscillations Induced by Optogenetic Theta Frequency Stimulation. J Neurosci 2016; 36:4155-69. [PMID: 27076416 DOI: 10.1523/jneurosci.3150-15.2016] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 02/18/2016] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Gamma oscillations (30-120 Hz) are thought to be important for various cognitive functions, including perception and working memory, and disruption of these oscillations has been implicated in brain disorders, such as schizophrenia and Alzheimer's disease. The cornu ammonis area 1 (CA1) of the hippocampus receives gamma frequency inputs from upstream regions (cornu ammonis area 3 and medial entorhinal cortex) and generates itself a faster gamma oscillation. The exact nature and origin of the intrinsic CA1 gamma oscillation is still under debate. Here, we expressed channel rhodopsin-2 under the CaMKIIα promoter in mice and prepared hippocampal slices to produce a model of intrinsic CA1 gamma oscillations. Sinusoidal optical stimulation of CA1 at theta frequency was found to induce robust theta-nested gamma oscillations with a temporal and spatial profile similar to CA1 gamma in vivo The results suggest the presence of a single gamma rhythm generator with a frequency range of 65-75 Hz at 32 °C. Pharmacological analysis found that the oscillations depended on both AMPA and GABAA receptors. Cell-attached and whole-cell recordings revealed that excitatory neuron firing slightly preceded interneuron firing within each gamma cycle, suggesting that this intrinsic CA1 gamma oscillation is generated with a pyramidal-interneuron circuit mechanism. SIGNIFICANCE STATEMENT This study demonstrates that the cornu ammonis area 1 (CA1) is capable of generating intrinsic gamma oscillations in response to theta input. This gamma generator is independent of activity in the upstream regions, highlighting that CA1 can produce its own gamma oscillation in addition to inheriting activity from the upstream regions. This supports the theory that gamma oscillations predominantly function to achieve local synchrony, and that a local gamma generated in each area conducts the signal to the downstream region.
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Herrik KF, Mørk A, Richard N, Bundgaard C, Bastlund JF, de Jong IE. The 5-HT 6 receptor antagonist idalopirdine potentiates the effects of acetylcholinesterase inhibition on neuronal network oscillations and extracellular acetylcholine levels in the rat dorsal hippocampus. Neuropharmacology 2016; 107:351-363. [DOI: 10.1016/j.neuropharm.2016.03.043] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 02/24/2016] [Accepted: 03/24/2016] [Indexed: 01/03/2023]
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16
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Li C, Wang J, Zhao J, Wang Y, Liu Z, Guo FL, Wang XF, Vreugdenhil M, Lu CB. Atorvastatin enhances kainate-induced gamma oscillations in rat hippocampal slices. Eur J Neurosci 2016; 44:2236-46. [PMID: 27336700 DOI: 10.1111/ejn.13322] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Revised: 06/16/2016] [Accepted: 06/21/2016] [Indexed: 01/16/2023]
Abstract
Atorvastatin has been shown to affect cognitive functions in rodents and humans. However, the underlying mechanism is not fully understood. Because hippocampal gamma oscillations (γ, 20-80 Hz) are associated with cognitive functions, we studied the effect of atorvastatin on persistent kainate-induced γ oscillation in the CA3 area of rat hippocampal slices. The involvement of NMDA receptors and multiple kinases was tested before and after administration of atorvastatin. Whole-cell current-clamp and voltage-clamp recordings were made from CA3 pyramidal neurons and interneurons before and after atorvastatin application. Atorvastatin increased γ power by ~ 50% in a concentration-dependent manner, without affecting dominant frequency. Whereas atorvastatin did not affect intrinsic properties of both pyramidal neurons and interneurons, it increased the firing frequency of interneurons but not that of pyramidal neurons. Furthermore, whereas atorvastatin did not affect synaptic current amplitude, it increased the frequency of spontaneous inhibitory post-synaptic currents, but did not affect the frequency of spontaneous excitatory post-synaptic currents. The atorvastatin-induced enhancement of γ oscillations was prevented by pretreatment with the PKA inhibitor H89, the ERK inhibitor U0126, or the PI3K inhibitor wortmanin, but not by the NMDA receptor antagonist D-AP5. Taken together, these results demonstrate that atorvastatin enhanced the kainate-induced γ oscillation by increasing interneuron excitability, with an involvement of multiple intracellular kinase pathways. Our study suggests that the classical cholesterol-lowering agent atorvastatin may improve cognitive functions compromised in disease, via the enhancement of hippocampal γ oscillations.
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Affiliation(s)
- Chengzhang Li
- Key Lab of Brain Research of Henan Province, Department of Physiology and Neurobiology, Xinxiang Medical University, Xinxiang, Henan, 453003, P.R. China
| | - Jiangang Wang
- Key Lab of Brain Research of Henan Province, Department of Physiology and Neurobiology, Xinxiang Medical University, Xinxiang, Henan, 453003, P.R. China
| | - Jianhua Zhao
- Department of Neurology, The First Affiliated Hospital of Xinxiang Medical University, Weihui, China
| | - Yali Wang
- Key Lab of Brain Research of Henan Province, Department of Physiology and Neurobiology, Xinxiang Medical University, Xinxiang, Henan, 453003, P.R. China
| | - Zhihua Liu
- Key Lab of Brain Research of Henan Province, Department of Physiology and Neurobiology, Xinxiang Medical University, Xinxiang, Henan, 453003, P.R. China
| | - Fang Li Guo
- Key Lab of Brain Research of Henan Province, Department of Physiology and Neurobiology, Xinxiang Medical University, Xinxiang, Henan, 453003, P.R. China
| | - Xiao Fang Wang
- Key Lab of Brain Research of Henan Province, Department of Physiology and Neurobiology, Xinxiang Medical University, Xinxiang, Henan, 453003, P.R. China
| | - Martin Vreugdenhil
- Department of Psychology, Xinxiang Medical University, Xinxiang, China.,School of Health and Education, Birmingham City University, Birmingham, UK
| | - Cheng Biao Lu
- Key Lab of Brain Research of Henan Province, Department of Physiology and Neurobiology, Xinxiang Medical University, Xinxiang, Henan, 453003, P.R. China
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17
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Dine J, Genewsky A, Hladky F, Wotjak CT, Deussing JM, Zieglgänsberger W, Chen A, Eder M. Local Optogenetic Induction of Fast (20-40 Hz) Pyramidal-Interneuron Network Oscillations in the In Vitro and In Vivo CA1 Hippocampus: Modulation by CRF and Enforcement of Perirhinal Theta Activity. Front Cell Neurosci 2016; 10:108. [PMID: 27199662 PMCID: PMC4844905 DOI: 10.3389/fncel.2016.00108] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 04/12/2016] [Indexed: 11/13/2022] Open
Abstract
The neurophysiological processes that can cause theta-to-gamma frequency range (4-80 Hz) network oscillations in the rhinal cortical-hippocampal system and the potential connectivity-based interactions of such forebrain rhythms are a topic of intensive investigation. Here, using selective Channelrhodopsin-2 (ChR2) expression in mouse forebrain glutamatergic cells, we were able to locally, temporally precisely, and reliably induce fast (20-40 Hz) field potential oscillations in hippocampal area CA1 in vitro (at 25°C) and in vivo (i.e., slightly anesthetized NEX-Cre-ChR2 mice). As revealed by pharmacological analyses and patch-clamp recordings from pyramidal cells and GABAergic interneurons in vitro, these light-triggered oscillations can exclusively arise from sustained suprathreshold depolarization (~200 ms or longer) and feedback inhibition of CA1 pyramidal neurons, as being mandatory for prototypic pyramidal-interneuron network (P-I) oscillations. Consistently, the oscillations comprised rhythmically occurring population spikes (generated by pyramidal cells) and their frequency increased with increasing spectral power. We further demonstrate that the optogenetically driven CA1 oscillations, which remain stable over repeated evocations, are impaired by the stress hormone corticotropin-releasing factor (CRF, 125 nM) in vitro and, even more remarkably, found that they are accompanied by concurrent states of enforced theta activity in the memory-associated perirhinal cortex (PrC) in vivo. The latter phenomenon most likely derives from neurotransmission via a known, but poorly studied excitatory CA1→PrC pathway. Collectively, our data provide evidence for the existence of a prototypic (CRF-sensitive) P-I gamma rhythm generator in area CA1 and suggest that CA1 P-I oscillations can rapidly up-regulate theta activity strength in hippocampus-innervated rhinal networks, at least in the PrC.
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Affiliation(s)
- Julien Dine
- Max Planck Institute of PsychiatryMunich, Germany; Department "Stress Neurobiology and Neurogenetics", Max Planck Institute of PsychiatryMunich, Germany; Scientific Core Unit "Electrophysiology and Neuronal Network Dynamics", Max Planck Institute of PsychiatryMunich, Germany
| | - Andreas Genewsky
- Max Planck Institute of PsychiatryMunich, Germany; Department "Stress Neurobiology and Neurogenetics", Max Planck Institute of PsychiatryMunich, Germany; Research Group "Neuronal Plasticity", Max Planck Institute of PsychiatryMunich, Germany
| | - Florian Hladky
- Max Planck Institute of PsychiatryMunich, Germany; Department "Stress Neurobiology and Neurogenetics", Max Planck Institute of PsychiatryMunich, Germany; Scientific Core Unit "Electrophysiology and Neuronal Network Dynamics", Max Planck Institute of PsychiatryMunich, Germany
| | - Carsten T Wotjak
- Max Planck Institute of PsychiatryMunich, Germany; Department "Stress Neurobiology and Neurogenetics", Max Planck Institute of PsychiatryMunich, Germany; Research Group "Neuronal Plasticity", Max Planck Institute of PsychiatryMunich, Germany
| | - Jan M Deussing
- Max Planck Institute of PsychiatryMunich, Germany; Department "Stress Neurobiology and Neurogenetics", Max Planck Institute of PsychiatryMunich, Germany; Research Group "Molecular Neurogenetics", Max Planck Institute of PsychiatryMunich, Germany
| | | | - Alon Chen
- Max Planck Institute of PsychiatryMunich, Germany; Department "Stress Neurobiology and Neurogenetics", Max Planck Institute of PsychiatryMunich, Germany; The Ruhman Family Laboratory for Research on the Neurobiology of Stress, Department of Neurobiology, Weizmann Institute of ScienceRehovot, Israel
| | - Matthias Eder
- Max Planck Institute of PsychiatryMunich, Germany; Department "Stress Neurobiology and Neurogenetics", Max Planck Institute of PsychiatryMunich, Germany; Scientific Core Unit "Electrophysiology and Neuronal Network Dynamics", Max Planck Institute of PsychiatryMunich, Germany
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18
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GettING in Touch With What Drives Your Inner Funky: Sources of CA1 Gamma Oscillations. Epilepsy Curr 2015; 15:271-3. [PMID: 26448733 DOI: 10.5698/1535-7511-15.5.271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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19
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Glykos V, Whittington MA, LeBeau FEN. Subregional differences in the generation of fast network oscillations in the rat medial prefrontal cortex (mPFC) in vitro. J Physiol 2015; 593:3597-615. [PMID: 26041504 PMCID: PMC4560586 DOI: 10.1113/jp270811] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 05/27/2015] [Indexed: 12/12/2022] Open
Abstract
KEY POINTS Fast network oscillations in the beta (20-30 Hz) frequency range can be evoked with combined activation of muscarinic and kainate receptors in different subregions of the medial prefrontal cortex (mPFC). Subregional differences were observed as the oscillations in the dorsal prelimbic cortex (PrL) were smaller in magnitude than those in the ventral dorsopeduncular (DP) region, and these differences persisted in trimmed slices containing only PrL and DP regions. Oscillations in both regions were dependent upon GABAA and AMPA receptor activation but NMDA receptor blockade decreased oscillations only in the DP region. Subregional differences in neuronal properties of the presumed pyramidal cells were found between PrL and DP, with many more cells in DP firing rhythmically compared to the PrL region. Presumed inhibitory synaptic potentials (IPSPs) recorded from principal cells were more rhythmic and coherent, and significantly larger in amplitude, in the DP region; the data suggest that variation in the patterns of activity between subregions may reflect distinct functional roles. ABSTRACT Fast network oscillations in the beta (20-30 Hz) and low gamma (30-80 Hz) range underlie higher cognitive functions associated with the medial prefrontal cortex (mPFC) including attention and working memory. Using a combination of kainate (KA, 200 nm) and the cholinergic agonist carbachol (Cb, 10 μm) fast network oscillations, in the beta frequency range, were evoked in the rat mPFC in vitro. Oscillations were elicited in the prelimbic (PrL), infralimbic (IL) and the dorsopeduncular (DP) cortex, with the largest oscillations observed in DP cortex. Oscillations in both the PrL and DP were dependent, with slightly different sensitivities, on γ-aminobutyric acid (GABA)A , α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and kainate receptors, but only oscillations in the DP were significantly reduced by N-methyl-d-aspartate (NMDA) receptor blockade. Intracellular recordings showed that 9/20 regular spiking (RS) cells in the PrL exhibited a notable cAMP-dependent hyperpolarisation activated current (Ih ) in contrast to 16/17 in the DP cortex. Extracellular single unit recordings showed that the majority of cells in the PrL, and DP regions had interspike firing frequencies (IFFs) at beta (20-30 Hz) frequencies and fired at the peak negativity of the field oscillation. Recordings in DP revealed presumed inhibitory postsynaptic potentials (IPSPs) that were larger in amplitude and more rhythmic than those in the PrL region. Our data suggest that each PFC subregion may be capable of generating distinct patterns of network activity with different cell types involved. Variation in the properties of oscillations evoked in the PrL and DP probably reflects the distinct functional roles of these different PFC regions.
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Affiliation(s)
- Vasileios Glykos
- Institute of Neuroscience, Newcastle University, Medical School, Framlington Place, Newcastle-upon-Tyne, NE2 4HH, UK
| | - Miles A Whittington
- York-Hull Medical School, F1- Department of Biology, York University, Heslington, YO10 5DD, UK
| | - Fiona E N LeBeau
- Institute of Neuroscience, Newcastle University, Medical School, Framlington Place, Newcastle-upon-Tyne, NE2 4HH, UK
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20
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Fast gamma oscillations are generated intrinsically in CA1 without the involvement of fast-spiking basket cells. J Neurosci 2015; 35:3616-24. [PMID: 25716860 DOI: 10.1523/jneurosci.4166-14.2015] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Information processing in neuronal networks relies on the precise synchronization of ensembles of neurons, coordinated by the diverse family of inhibitory interneurons. Cortical interneurons can be usefully parsed by embryonic origin, with the vast majority arising from either the caudal or medial ganglionic eminences (CGE and MGE). Here, we examine the activity of hippocampal interneurons during gamma oscillations in mouse CA1, using an in vitro model where brief epochs of rhythmic activity were evoked by local application of kainate. We found that this CA1 KA-evoked gamma oscillation was faster than that in CA3 and, crucially, did not appear to require the involvement of fast-spiking basket cells. In contrast to CA3, we also found that optogenetic inhibition of pyramidal cells in CA1 did not significantly affect the power of the oscillation, suggesting that excitation may not be essential for gamma genesis in this region. We found that MGE-derived interneurons were generally more active than CGE interneurons during CA1 gamma, although a group of CGE-derived interneurons, putative trilaminar cells, were strongly phase-locked with gamma oscillations and, together with MGE-derived axo-axonic and bistratified cells, provide attractive candidates for being the driver of this locally generated, predominantly interneuron-driven model of gamma oscillations.
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21
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Butler JL, Paulsen O. Hippocampal network oscillations - recent insights from in vitro experiments. Curr Opin Neurobiol 2015; 31:40-4. [PMID: 25137641 DOI: 10.1016/j.conb.2014.07.025] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Revised: 07/26/2014] [Accepted: 07/30/2014] [Indexed: 01/07/2023]
Abstract
Network oscillations are present throughout the mammalian brain. They are important for certain cognitive functions, such as learning and memory. The hippocampus exhibits prominent oscillations similar to those seen in other parts of the cortex. Due to its highly organised lamellar structure, ex vivo and in vitro preparations from the hippocampus have provided experimental models within which to study network oscillations. As such, experiments in hippocampal slices continue to progress our understanding about both the mechanisms and functions of cortical network oscillations. Here, advances from the past two years are summarised, and the current state of the field discussed.
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Affiliation(s)
- James L Butler
- Department of Physiology, Development and Neuroscience, University of Cambridge, Physiological Laboratory, Downing Street, Cambridge CB2 3EG, United Kingdom
| | - Ole Paulsen
- Department of Physiology, Development and Neuroscience, University of Cambridge, Physiological Laboratory, Downing Street, Cambridge CB2 3EG, United Kingdom.
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22
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Abstract
The human connectome will provide a detailed mapping of the brain's connectivity, with fundamental insights for health and disease. However, further understanding of brain function and dysfunction will require an integrated framework that links brain connectivity with brain dynamics, as well as the biological details that relate this connectivity more directly to function. In this Perspective, we describe such a framework for studying the brain's "dynome" and its relationship to cognition.
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Affiliation(s)
- Nancy J Kopell
- Department of Mathematics and Statistics, Boston University, Boston, MA 02215, USA.
| | - Howard J Gritton
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - Miles A Whittington
- The Hull York Medical School, University of York, Heslington, York YO10 5DD, UK
| | - Mark A Kramer
- Department of Mathematics and Statistics, Boston University, Boston, MA 02215, USA
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Alger BE, Nagode DA, Tang AH. Muscarinic cholinergic receptors modulate inhibitory synaptic rhythms in hippocampus and neocortex. Front Synaptic Neurosci 2014; 6:18. [PMID: 25249974 PMCID: PMC4155787 DOI: 10.3389/fnsyn.2014.00018] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Accepted: 07/29/2014] [Indexed: 01/08/2023] Open
Abstract
Activation of muscarinic acetylcholine (ACh) receptors (mAChRs) powerfully affects many neuronal properties as well as numerous cognitive behaviors. Small neuronal circuits constitute an intermediate level of organization between neurons and behaviors, and mAChRs affect interactions among cells that compose these circuits. Circuit activity is often assessed by extracellular recordings of the local field potentials (LFPs), which are analogous to in vivo EEGs, generated by coordinated neuronal interactions. Coherent forms of physiologically relevant circuit activity manifest themselves as rhythmic oscillations in the LFPs. Frequencies of rhythmic oscillations that are most closely associated with animal behavior are in the range of 4–80 Hz, which is subdivided into theta (4–14 Hz), beta (15–29 Hz) and gamma (30–80 Hz) bands. Activation of mAChRs triggers rhythmic oscillations in these bands in the hippocampus and neocortex. Inhibitory responses mediated by GABAergic interneurons constitute a prominent feature of these oscillations, and indeed, appear to be their major underlying factor in many cases. An important issue is which interneurons are involved in rhythm generation. Besides affecting cellular and network properties directly, mAChRs can cause the mobilization of endogenous cannabinoids (endocannabinoids, eCBs) that, by acting on the principal cannabinoid receptor of the brain, CB1R, regulate the release of certain neurotransmitters, including GABA. CB1Rs are heavily expressed on only a subset of interneurons and, at lower density, on glutamatergic neurons. Exogenous cannabinoids typically disrupt oscillations in the theta (θ) and gamma (γ) ranges, which probably contributes to the behavioral effects of these drugs. It is important to understand how neuronal circuit activity is affected by mAChR-driven eCBs, as this information will provide deeper insight into the actions of ACh itself, as well as into the effects of eCBs and exogenous cannabinoids in animal behavior. After covering some basic aspects of the mAChR system, this review will focus on recent findings concerning the mechanisms and circuitry that generate θ and γ rhythms in hippocampus and neocortex. The ability of optogenetic methods to probe the many roles of ACh in rhythm generation is highlighted.
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Affiliation(s)
- Bradley E Alger
- Department of Physiology, University of Maryland School of Medicine Baltimore, MD, USA ; Department of Psychiatry, University of Maryland School of Medicine Baltimore, MD, USA ; Program in Neuroscience, Graduate School, University of Maryland Baltimore Baltimore, MD, USA
| | - Daniel A Nagode
- Department of Biology, University of Maryland College Park College Park, MD, USA
| | - Ai-Hui Tang
- Department of Physiology, University of Maryland School of Medicine Baltimore, MD, USA
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