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Yu X, Yang H, Lv H, Lu H, Zhao H, Xu Z. Age-Dependent Phenomena of 6-Hz Corneal Kindling Model in Mice. Mol Neurobiol 2024; 61:5601-5613. [PMID: 38214837 DOI: 10.1007/s12035-024-03934-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Accepted: 01/05/2024] [Indexed: 01/13/2024]
Abstract
Although numerous studies have acknowledged disparities in epilepsy-related disease processes between young and aged animals, little is known about how epilepsy changes from young adulthood to middle age. This study investigates the impact of aging on 6-Hz corneal kindling in young-adult mice and middle-aged mice. We found that the kindling acquisition of the 6-Hz corneal kindling model was delayed in middle-aged mice when compared to young-adult mice. While the seizure stage and incidence of generalized seizures (GS) were similar between the two age groups, the duration of GS in the kindled middle-aged mice was shorter than that in the kindled young-adult mice. Besides, all kindled mice, regardless of age, were resistant to phenytoin sodium (PHT), valproate sodium (VPA), and lamotrigine (LGT), whereas middle-aged mice exhibited higher levetiracetam (LEV) resistance compared to young-adult mice. Both age groups of kindled mice displayed hyperactivity and impaired memory, which are common behavioral characteristics associated with epilepsy. Furthermore, middle-aged mice displayed more pronounced astrogliosis in the hippocampus. Additionally, the expression of Brain-Derived Neurotrophic Factor (BDNF) was lower in middle-aged mice than in young-adult mice prior to kindling. These data demonstrate that both the acquisition and expression of 6-Hz corneal kindling are attenuated in middle-aged mice, while hippocampal astrogliosis and pharmacological resistance are more pronounced in this age group. These results underscore the importance of considering age-related factors when utilizing the 6-Hz corneal kindling model in mice of varying age groups.
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Affiliation(s)
- Xiu Yu
- Laboratory of Rheumatology & Institute of TCM Clinical Basic Medicine, College of Basic Medical Science, Zhejiang Chinese Medical University, No.548 Binwen Road, Hangzhou, Zhejiang, 310053, China
- Key Laboratory of Chinese Medicine Rheumatology of Zhejiang Province, College of Basic Medical Science, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China
| | - Han Yang
- Laboratory of Rheumatology & Institute of TCM Clinical Basic Medicine, College of Basic Medical Science, Zhejiang Chinese Medical University, No.548 Binwen Road, Hangzhou, Zhejiang, 310053, China
- Key Laboratory of Chinese Medicine Rheumatology of Zhejiang Province, College of Basic Medical Science, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China
| | - HongJie Lv
- Laboratory of Rheumatology & Institute of TCM Clinical Basic Medicine, College of Basic Medical Science, Zhejiang Chinese Medical University, No.548 Binwen Road, Hangzhou, Zhejiang, 310053, China
- Key Laboratory of Chinese Medicine Rheumatology of Zhejiang Province, College of Basic Medical Science, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China
| | - Haimei Lu
- Laboratory of Rheumatology & Institute of TCM Clinical Basic Medicine, College of Basic Medical Science, Zhejiang Chinese Medical University, No.548 Binwen Road, Hangzhou, Zhejiang, 310053, China
- Key Laboratory of Chinese Medicine Rheumatology of Zhejiang Province, College of Basic Medical Science, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China
| | - Huawei Zhao
- Department of Pharmacy, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, China.
| | - Zhenghao Xu
- Laboratory of Rheumatology & Institute of TCM Clinical Basic Medicine, College of Basic Medical Science, Zhejiang Chinese Medical University, No.548 Binwen Road, Hangzhou, Zhejiang, 310053, China.
- Key Laboratory of Chinese Medicine Rheumatology of Zhejiang Province, College of Basic Medical Science, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China.
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, College of Basic Medical Science, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China.
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2
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Tavakol S, Kebets V, Royer J, Li Q, Auer H, DeKraker J, Jefferies E, Bernasconi N, Bernasconi A, Helmstaedter C, Arafat T, Armony J, Nathan Spreng R, Caciagli L, Frauscher B, Smallwood J, Bernhardt B. Differential relational memory impairment in temporal lobe epilepsy. Epilepsy Behav 2024; 155:109722. [PMID: 38643660 DOI: 10.1016/j.yebeh.2024.109722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 02/22/2024] [Accepted: 02/25/2024] [Indexed: 04/23/2024]
Abstract
OBJECTIVE Temporal lobe epilepsy (TLE) is typically associated with pathology of the hippocampus, a key structure involved in relational memory, including episodic, semantic, and spatial memory processes. While it is widely accepted that TLE-associated hippocampal alterations underlie memory deficits, it remains unclear whether impairments relate to a specific cognitive domain or multiple ones. METHODS We administered a recently validated task paradigm to evaluate episodic, semantic, and spatial memory in 24 pharmacoresistant TLE patients and 50 age- and sex-matched healthy controls. We carried out two-way analyses of variance to identify memory deficits in individuals with TLE relative to controls across different relational memory domains, and used partial least squares correlation to identify factors contributing to variations in relational memory performance across both cohorts. RESULTS Compared to controls, TLE patients showed marked impairments in episodic and spatial memory, with mixed findings in semantic memory. Even when additionally controlling for age, sex, and overall cognitive function, between-group differences persisted along episodic and spatial domains. Moreover, age, diagnostic group, and hippocampal volume were all associated with relational memory behavioral phenotypes. SIGNIFICANCE Our behavioral findings show graded deficits across relational memory domains in people with TLE, which provides further insights into the complex pattern of cognitive impairment in the condition.
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Affiliation(s)
- Shahin Tavakol
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada.
| | - Valeria Kebets
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada.
| | - Jessica Royer
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada.
| | - Qiongling Li
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada.
| | - Hans Auer
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada.
| | - Jordan DeKraker
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada.
| | | | - Neda Bernasconi
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada.
| | - Andrea Bernasconi
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada.
| | | | - Thaera Arafat
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada.
| | - Jorge Armony
- Department of Psychiatry, McGill University, Montreal, Canada.
| | - R Nathan Spreng
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada; Department of Neurology and Neurosurgery, Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada.
| | - Lorenzo Caciagli
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; UCL Queen Square Institute of Neurology, London, United Kingdom
| | - Birgit Frauscher
- ANPHY Lab, Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada.
| | | | - Boris Bernhardt
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada; Department of Neurology and Neurosurgery, Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada.
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3
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Bird AD, Cuntz H, Jedlicka P. Robust and consistent measures of pattern separation based on information theory and demonstrated in the dentate gyrus. PLoS Comput Biol 2024; 20:e1010706. [PMID: 38377108 PMCID: PMC10906873 DOI: 10.1371/journal.pcbi.1010706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 03/01/2024] [Accepted: 12/13/2023] [Indexed: 02/22/2024] Open
Abstract
Pattern separation is a valuable computational function performed by neuronal circuits, such as the dentate gyrus, where dissimilarity between inputs is increased, reducing noise and increasing the storage capacity of downstream networks. Pattern separation is studied from both in vivo experimental and computational perspectives and, a number of different measures (such as orthogonalisation, decorrelation, or spike train distance) have been applied to quantify the process of pattern separation. However, these are known to give conclusions that can differ qualitatively depending on the choice of measure and the parameters used to calculate it. We here demonstrate that arbitrarily increasing sparsity, a noticeable feature of dentate granule cell firing and one that is believed to be key to pattern separation, typically leads to improved classical measures for pattern separation even, inappropriately, up to the point where almost all information about the inputs is lost. Standard measures therefore both cannot differentiate between pattern separation and pattern destruction, and give results that may depend on arbitrary parameter choices. We propose that techniques from information theory, in particular mutual information, transfer entropy, and redundancy, should be applied to penalise the potential for lost information (often due to increased sparsity) that is neglected by existing measures. We compare five commonly-used measures of pattern separation with three novel techniques based on information theory, showing that the latter can be applied in a principled way and provide a robust and reliable measure for comparing the pattern separation performance of different neurons and networks. We demonstrate our new measures on detailed compartmental models of individual dentate granule cells and a dentate microcircuit, and show how structural changes associated with epilepsy affect pattern separation performance. We also demonstrate how our measures of pattern separation can predict pattern completion accuracy. Overall, our measures solve a widely acknowledged problem in assessing the pattern separation of neural circuits such as the dentate gyrus, as well as the cerebellum and mushroom body. Finally we provide a publicly available toolbox allowing for easy analysis of pattern separation in spike train ensembles.
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Affiliation(s)
- Alexander D. Bird
- Computer-Based Modelling in the field of 3R Animal Protection, ICAR3R, Faculty of Medicine, Justus Liebig University, Giessen, Germany
- Ernst Strüngmann Institute (ESI) for Neuroscience in cooperation with the Max Planck Society, Frankfurt-am-Main, Germany
- Frankfurt Institute for Advanced Studies, Frankfurt-am-Main, Germany
- Translational Neuroscience Network Giessen, Germany
| | - Hermann Cuntz
- Ernst Strüngmann Institute (ESI) for Neuroscience in cooperation with the Max Planck Society, Frankfurt-am-Main, Germany
- Frankfurt Institute for Advanced Studies, Frankfurt-am-Main, Germany
- Translational Neuroscience Network Giessen, Germany
| | - Peter Jedlicka
- Computer-Based Modelling in the field of 3R Animal Protection, ICAR3R, Faculty of Medicine, Justus Liebig University, Giessen, Germany
- Translational Neuroscience Network Giessen, Germany
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4
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Proddutur A, Nguyen S, Yeh CW, Gupta A, Santhakumar V. Reclusive chandeliers: Functional isolation of dentate axo-axonic cells after experimental status epilepticus. Prog Neurobiol 2023; 231:102542. [PMID: 37898313 PMCID: PMC10842856 DOI: 10.1016/j.pneurobio.2023.102542] [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: 05/02/2023] [Revised: 10/22/2023] [Accepted: 10/24/2023] [Indexed: 10/30/2023]
Abstract
Axo-axonic cells (AACs) provide specialized inhibition to the axon initial segment (AIS) of excitatory neurons and can regulate network output and synchrony. Although hippocampal dentate AACs are structurally altered in epilepsy, physiological analyses of dentate AACs are lacking. We demonstrate that parvalbumin neurons in the dentate molecular layer express PTHLH, an AAC marker, and exhibit morphology characteristic of AACs. Dentate AACs show high-frequency, non-adapting firing but lack persistent firing in the absence of input and have higher rheobase than basket cells suggesting that AACs can respond reliably to network activity. Early after pilocarpine-induced status epilepticus (SE), dentate AACs receive fewer spontaneous excitatory and inhibitory synaptic inputs and have significantly lower maximum firing frequency. Paired recordings and spatially localized optogenetic stimulation revealed that SE reduced the amplitude of unitary synaptic inputs from AACs to granule cells without altering reliability, short-term plasticity, or AIS GABA reversal potential. These changes compromised AAC-dependent shunting of granule cell firing in a multicompartmental model. These early post-SE changes in AAC physiology would limit their ability to receive and respond to input, undermining a critical brake on the dentate throughput during epileptogenesis.
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Affiliation(s)
- Archana Proddutur
- Department of Pharmacology, Physiology and Neuroscience, Rutgers New Jersey Medical School, Newark, NJ 07103, USA; Department of Molecular, Cell and Systems Biology, University of California Riverside, Riverside, CA 92521, USA
| | - Susan Nguyen
- Department of Molecular, Cell and Systems Biology, University of California Riverside, Riverside, CA 92521, USA
| | - Chia-Wei Yeh
- Department of Molecular, Cell and Systems Biology, University of California Riverside, Riverside, CA 92521, USA
| | - Akshay Gupta
- Department of Pharmacology, Physiology and Neuroscience, Rutgers New Jersey Medical School, Newark, NJ 07103, USA; Department of Molecular, Cell and Systems Biology, University of California Riverside, Riverside, CA 92521, USA
| | - Vijayalakshmi Santhakumar
- Department of Pharmacology, Physiology and Neuroscience, Rutgers New Jersey Medical School, Newark, NJ 07103, USA; Department of Molecular, Cell and Systems Biology, University of California Riverside, Riverside, CA 92521, USA.
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5
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Corrubia L, Huang A, Nguyen S, Shiflett MW, Jones MV, Ewell LA, Santhakumar V. Early deficits in dentate circuit and behavioral pattern separation after concussive brain injury. Exp Neurol 2023; 370:114578. [PMID: 37858696 PMCID: PMC10712990 DOI: 10.1016/j.expneurol.2023.114578] [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: 06/28/2023] [Revised: 09/28/2023] [Accepted: 10/16/2023] [Indexed: 10/21/2023]
Abstract
Traumatic brain injury leads to cellular and circuit changes in the dentate gyrus, a gateway to hippocampal information processing. Intrinsic granule cell firing properties and strong feedback inhibition in the dentate are proposed as critical to its ability to generate unique representation of similar inputs by a process known as pattern separation. Here we evaluate the impact of brain injury on cellular decorrelation of temporally patterned inputs in slices and behavioral discrimination of spatial locations in vivo one week after concussive lateral fluid percussion injury (FPI) in mice. Despite posttraumatic increases in perforant path evoked excitatory drive to granule cells and enhanced ΔFosB labeling, indicating sustained increase in excitability, the reliability of granule cell spiking was not compromised after FPI. Although granule cells continued to effectively decorrelate output spike trains recorded in response to similar temporally patterned input sets after FPI, their ability to decorrelate highly similar input patterns was reduced. In parallel, encoding of similar spatial locations in a novel object location task that involves the dentate inhibitory circuits was impaired one week after FPI. Injury induced changes in pattern separation were accompanied by loss of somatostatin expressing inhibitory neurons in the hilus. Together, these data suggest that the early posttraumatic changes in the dentate circuit undermine dentate circuit decorrelation of temporal input patterns as well as behavioral discrimination of similar spatial locations, both of which could contribute to deficits in episodic memory.
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Affiliation(s)
- Lucas Corrubia
- Department of Pharmacology, Physiology and Neuroscience, Rutgers New Jersey Medical School, Newark, NJ 07103, USA; Department of Molecular, Cell and Systems Biology, University of California Riverside, Riverside, CA 92521, USA
| | - Andrew Huang
- Department of Molecular, Cell and Systems Biology, University of California Riverside, Riverside, CA 92521, USA
| | - Susan Nguyen
- Department of Molecular, Cell and Systems Biology, University of California Riverside, Riverside, CA 92521, USA
| | | | - Mathew V Jones
- Department of Neuroscience, University of Wisconsin, Madison, WI 53705, USA
| | - Laura A Ewell
- Department of Anatomy and Neurobiology, University of California Irvine, Irvine, CA 92697, USA
| | - Vijayalakshmi Santhakumar
- Department of Pharmacology, Physiology and Neuroscience, Rutgers New Jersey Medical School, Newark, NJ 07103, USA; Department of Molecular, Cell and Systems Biology, University of California Riverside, Riverside, CA 92521, USA.
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6
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Proddutur A, Nguyen S, Yeh CW, Gupta A, Santhakumar V. RECLUSIVE CHANDELIERS: FUNCTIONAL ISOLATION OF DENTATE AXO-AXONIC CELLS AFTER EXPERIMENTAL STATUS EPILEPTICUS. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.01.560378. [PMID: 37873292 PMCID: PMC10592856 DOI: 10.1101/2023.10.01.560378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
Axo-axonic cells (AACs) provide specialized inhibition to the axon initial segment (AIS) of excitatory neurons and can regulate network output and synchrony. Although hippocampal dentate AACs are structurally altered in epilepsy, physiological analyses of dentate AACs are lacking. We demonstrate that parvalbumin neurons in the dentate molecular layer express PTHLH, an AAC marker, and exhibit morphology characteristic of AACs. Dentate AACs show high-frequency, non-adapting firing but lack persistent firing in the absence of input and have higher rheobase than basket cells suggesting that AACs can respond reliably to network activity. Early after pilocarpine-induced status epilepticus (SE), dentate AACs receive fewer spontaneous excitatory and inhibitory synaptic inputs and have significantly lower maximum firing frequency. Paired recordings and spatially localized optogenetic stimulation revealed that SE reduced the amplitude of unitary synaptic inputs from AACs to granule cells without altering reliability, short-term plasticity, or AIS GABA reversal potential. These changes compromised AAC-dependent shunting of granule cell firing in a multicompartmental model. These early post-SE changes in AAC physiology would limit their ability to receive and respond to input, undermining a critical brake on the dentate throughput during epileptogenesis.
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Affiliation(s)
- Archana Proddutur
- Department of Pharmacology, Physiology and Neuroscience, Rutgers New Jersey Medical School, Newark, New Jersey 07103
- Department of Molecular, Cell and Systems Biology, University of California Riverside, Riverside, California 92521
| | - Susan Nguyen
- Department of Molecular, Cell and Systems Biology, University of California Riverside, Riverside, California 92521
| | - Chia-Wei Yeh
- Department of Molecular, Cell and Systems Biology, University of California Riverside, Riverside, California 92521
| | - Akshay Gupta
- Department of Pharmacology, Physiology and Neuroscience, Rutgers New Jersey Medical School, Newark, New Jersey 07103
- Department of Molecular, Cell and Systems Biology, University of California Riverside, Riverside, California 92521
| | - Vijayalakshmi Santhakumar
- Department of Pharmacology, Physiology and Neuroscience, Rutgers New Jersey Medical School, Newark, New Jersey 07103
- Department of Molecular, Cell and Systems Biology, University of California Riverside, Riverside, California 92521
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7
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Corrubia L, Huang A, Nguyen S, Shiflett MW, Jones MV, Ewell LA, Santhakumar V. Early Deficits in Dentate Circuit and Behavioral Pattern Separation after Concussive Brain Injury. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.22.546120. [PMID: 37745454 PMCID: PMC10515770 DOI: 10.1101/2023.06.22.546120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
Traumatic brain injury leads to cellular and circuit changes in the dentate gyrus, a gateway to hippocampal information processing. Intrinsic granule cell firing properties and strong feedback inhibition in the dentate are proposed as critical to its ability to generate unique representation of similar inputs by a process known as pattern separation. Here we evaluate the impact of brain injury on cellular decorrelation of temporally patterned inputs in slices and behavioral discrimination of spatial locations in vivo one week after concussive lateral fluid percussion injury (FPI) in mice. Despite posttraumatic increases in perforant path evoked excitatory drive to granule cells and enhanced ΔFosB labeling, indicating sustained increase in excitability, the reliability of granule cell spiking was not compromised after FPI. Although granule cells continued to effectively decorrelate output spike trains recorded in response to similar temporally patterned input sets after FPI, their ability to decorrelate highly similar input patterns was reduced. In parallel, encoding of similar spatial locations in a novel object location task that involves the dentate inhibitory circuits was impaired one week after FPI. Injury induced changes in pattern separation were accompanied by loss of somatostatin expressing inhibitory neurons in the hilus. Together, these data suggest that the early posttraumatic changes in the dentate circuit undermine dentate circuit decorrelation of temporal input patterns as well as behavioral discrimination of similar spatial locations, both of which could contribute to deficits in episodic memory.
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Affiliation(s)
- Lucas Corrubia
- Department of Pharmacology, Physiology and Neuroscience, Rutgers New Jersey Medical School, Newark, New Jersey 07103
- Department of Molecular, Cell and Systems Biology, University of California Riverside, Riverside, California 92521
| | - Andrew Huang
- Department of Molecular, Cell and Systems Biology, University of California Riverside, Riverside, California 92521
| | - Susan Nguyen
- Department of Molecular, Cell and Systems Biology, University of California Riverside, Riverside, California 92521
| | | | - Mathew V. Jones
- Department of Neuroscience, University of Wisconsin, Madison, WI, 53705
| | - Laura A. Ewell
- Department of Anatomy and Neurobiology, University of California Irvine, Irvine, California 92697
| | - Vijayalakshmi Santhakumar
- Department of Pharmacology, Physiology and Neuroscience, Rutgers New Jersey Medical School, Newark, New Jersey 07103
- Department of Molecular, Cell and Systems Biology, University of California Riverside, Riverside, California 92521
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8
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Gonzalez JC, Lee H, Vincent AM, Hill AL, Goode LK, King GD, Gamble KL, Wadiche JI, Overstreet-Wadiche L. Circadian regulation of dentate gyrus excitability mediated by G-protein signaling. Cell Rep 2023; 42:112039. [PMID: 36749664 PMCID: PMC10404305 DOI: 10.1016/j.celrep.2023.112039] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 10/27/2022] [Accepted: 01/12/2023] [Indexed: 02/08/2023] Open
Abstract
The central circadian regulator within the suprachiasmatic nucleus transmits time of day information by a diurnal spiking rhythm driven by molecular clock genes controlling membrane excitability. Most brain regions, including the hippocampus, harbor similar intrinsic circadian transcriptional machinery, but whether these molecular programs generate oscillations of membrane properties is unclear. Here, we show that intrinsic excitability of mouse dentate granule neurons exhibits a 24-h oscillation that controls spiking probability. Diurnal changes in excitability are mediated by antiphase G-protein regulation of potassium and sodium currents that reduce excitability during the Light phase. Disruption of the circadian transcriptional machinery by conditional deletion of Bmal1 enhances excitability selectively during the Light phase by removing G-protein regulation. These results reveal that circadian transcriptional machinery regulates intrinsic excitability by coordinated regulation of ion channels by G-protein signaling, highlighting a potential novel mechanism of cell-autonomous oscillations.
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Affiliation(s)
- Jose Carlos Gonzalez
- Department of Neurobiology and McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Haeun Lee
- Department of Neurobiology and McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Angela M Vincent
- Department of Neurobiology and McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Angela L Hill
- Department of Neurobiology and McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Lacy K Goode
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Gwendalyn D King
- Department of Biology, Creighton University, Omaha, NE 68178, USA
| | - Karen L Gamble
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Jacques I Wadiche
- Department of Neurobiology and McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
| | - Linda Overstreet-Wadiche
- Department of Neurobiology and McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
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9
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Comino Garcia-Munoz A, Alemán-Gómez Y, Toledano R, Poch C, García-Morales I, Aledo-Serrano Á, Gil-Nagel A, Campo P. Morphometric and microstructural characteristics of hippocampal subfields in mesial temporal lobe epilepsy and their correlates with mnemonic discrimination. Front Neurol 2023; 14:1096873. [PMID: 36864916 PMCID: PMC9972498 DOI: 10.3389/fneur.2023.1096873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Accepted: 01/18/2023] [Indexed: 02/16/2023] Open
Abstract
Introduction Pattern separation (PS) is a fundamental aspect of memory creation that defines the ability to transform similar memory representations into distinct ones, so they do not overlap when storing and retrieving them. Experimental evidence in animal models and the study of other human pathologies have demonstrated the role of the hippocampus in PS, in particular of the dentate gyrus (DG) and CA3. Patients with mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HE) commonly report mnemonic deficits that have been associated with failures in PS. However, the link between these impairments and the integrity of the hippocampal subfields in these patients has not yet been determined. The aim of this work is to explore the association between the ability to perform mnemonic functions and the integrity of hippocampal CA1, CA3, and DG in patients with unilateral MTLE-HE. Method To reach this goal we evaluated the memory of patients with an improved object mnemonic similarity test. We then analyzed the hippocampal complex structural and microstructural integrity using diffusion weighted imaging. Results Our results indicate that patients with unilateral MTLE-HE present alterations in both volume and microstructural properties at the level of the hippocampal subfields DG, CA1, CA3, and the subiculum, that sometimes depend on the lateralization of their epileptic focus. However, none of the specific changes was found to be directly related to the performance of the patients in a pattern separation task, which might indicate a contribution of various alterations to the mnemonic deficits or the key contribution of other structures to the function. Discussion we established for the first time the alterations in both the volume and the microstructure at the level of the hippocampal subfields in a group of unilateral MTLE patients. We observed that these changes are greater in the DG and CA1 at the macrostructural level, and in CA3 and CA1 in the microstructural level. None of these changes had a direct relation to the performance of the patients in a pattern separation task, which suggests a contribution of various alterations to the loss of function.
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Affiliation(s)
- Alicia Comino Garcia-Munoz
- Centre de Résonance Magnétique Biologique et Médicale-Unité Mixte de Recherche 7339, Aix-Marseille Université, Marseille, France
| | - Yasser Alemán-Gómez
- Connectomics Lab, Lausanne University Hospital (CHUV), Lausanne, Switzerland
| | - Rafael Toledano
- Epilepsy Unit, Neurology Department, Hospital Ruber Internacional, Madrid, Spain,Epilepsy Unit, Neurology Department, University Hospital Ramón y Cajal, Madrid, Spain
| | - Claudia Poch
- Facultad de Lenguas y Educación, Universidad de Nebrija, Madrid, Spain
| | - Irene García-Morales
- Epilepsy Unit, Neurology Department, Hospital Ruber Internacional, Madrid, Spain,Epilepsy Unit, Neurology Department, University Hospital of San Carlos, Madrid, Spain
| | - Ángel Aledo-Serrano
- Epilepsy Unit, Neurology Department, Hospital Ruber Internacional, Madrid, Spain
| | - Antonio Gil-Nagel
- Epilepsy Unit, Neurology Department, Hospital Ruber Internacional, Madrid, Spain
| | - Pablo Campo
- Department of Basic Psychology, Autonoma University of Madrid, Madrid, Spain,*Correspondence: Pablo Campo ✉
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10
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Kilianski S, Beenhakker MP. Patterns of Pathology. Epilepsy Curr 2023; 23:56-57. [PMID: 36923347 PMCID: PMC10009130 DOI: 10.1177/15357597221137212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Deficits in Behavioral and Neuronal Pattern Separation in Temporal Lobe Epilepsy Madar AD, Pfammatter JA, Bordenave J, Plumley EI, Ravi S, Cowie M, Wallace EP, Hermann BP, Maganti RK, Jones MV. J Neurosci . 2021;41(46):9669-9686. doi:10.1523/JNEUROSCI.2439-20.2021 In temporal lobe epilepsy, the ability of the dentate gyrus to limit excitatory cortical input to the hippocampus breaks down, leading to seizures. The dentate gyrus is also thought to help discriminate between similar memories by performing pattern separation, but whether epilepsy leads to a breakdown in this neural computation, and thus to mnemonic discrimination impairments, remains unknown. Here we show that temporal lobe epilepsy is characterized by behavioral deficits in mnemonic discrimination tasks, in both humans (females and males) and mice (C57Bl6 males, systemic low-dose kainate model). Using a recently developed assay in brain slices of the same epileptic mice, we reveal a decreased ability of the dentate gyrus to perform certain forms of pattern separation. This is because of a subset of granule cells with abnormal bursting that can develop independently of early EEG abnormalities. Overall, our results linking physiology, computation, and cognition in the same mice advance our understanding of episodic memory mechanisms and their dysfunction in epilepsy.
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Rukundo P, Feng T, Pham V, Pieraut S. Moderate effect of early-life experience on dentate gyrus function. Mol Brain 2022; 15:92. [PMID: 36411441 PMCID: PMC9677655 DOI: 10.1186/s13041-022-00980-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 11/06/2022] [Indexed: 11/22/2022] Open
Abstract
The development, maturation, and plasticity of neural circuits are strongly influenced by experience and the interaction of an individual with their environment can have a long-lasting effect on cognitive function. Using an enriched environment (EE) paradigm, we have recently demonstrated that enhancing social, physical, and sensory activity during the pre-weaning time in mice led to an increase of inhibitory and excitatory synapses in the dentate gyrus (DG) of the hippocampus. The structural plasticity induced by experience may affect information processing in the circuit. The DG performs pattern separation, a computation that enables the encoding of very similar and overlapping inputs into dissimilar outputs. In the presented study, we have tested the hypothesis that an EE in juvenile mice will affect DG's functions that are relevant for pattern separation: the decorrelation of the inputs from the entorhinal cortex (EC) and the recruitment of the principal excitatory granule cell (GC) during behavior. First, using a novel slice electrophysiology protocol, we found that the transformation of the incoming signal from the EC afferents by individual GC is moderately affected by EE. We further show that EE does not affect behaviorally induced recruitment of principal excitatory GC. Lastly, using the novel object recognition task, a hippocampus-dependent memory test, we show that the ontogeny of this discrimination task was similar among the EE mice and the controls. Taken together, our work demonstrates that pre-weaning enrichment moderately affects DG function.
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Affiliation(s)
- Pacifique Rukundo
- grid.266818.30000 0004 1936 914XDepartment of Biology, University of Nevada, Reno, NV 89557 USA
| | - Ting Feng
- grid.266818.30000 0004 1936 914XDepartment of Biology, University of Nevada, Reno, NV 89557 USA
| | - Vincent Pham
- grid.266818.30000 0004 1936 914XDepartment of Biology, University of Nevada, Reno, NV 89557 USA
| | - Simon Pieraut
- grid.266818.30000 0004 1936 914XDepartment of Biology, University of Nevada, Reno, NV 89557 USA
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Early death in a mouse model of Alzheimer's disease exacerbated by microglial loss of TAM receptor signaling. Proc Natl Acad Sci U S A 2022; 119:e2204306119. [PMID: 36191221 PMCID: PMC9564325 DOI: 10.1073/pnas.2204306119] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Recurrent seizure is a common comorbidity in early-stage Alzheimer's disease (AD) and may contribute to AD pathogenesis and cognitive decline. Similarly, many mouse models of Alzheimer's disease that overproduce amyloid beta are prone to epileptiform seizures that may result in early sudden death. We studied one such model, designated APP/PS1, and found that mutation of the TAM receptor tyrosine kinase (RTK) Mer or its ligand Gas6 greatly exacerbated early death. Lethality was tied to violent seizures that appeared to initiate in the dentate gyrus (DG) of the hippocampus, where Mer plays an essential role in the microglial phagocytosis of both apoptotic and newborn cells normally generated during adult neurogenesis. We found that newborn DG neurons and excitatory synapses between the DG and the cornu ammonis field 3 (CA3) field of the hippocampus were increased in TAM-deficient mice, and that premature death and adult neurogenesis in these mice were coincident. In contrast, the incidence of lethal seizures and the deposition of dense-core amyloid plaques were strongly anticorrelated. Together, these results argue that TAM-mediated phagocytosis sculpts synaptic connectivity in the hippocampus, and that seizure-inducing amyloid beta polymers are present prior to the formation of dense-core plaques.
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Kandeda AK, Nodeina S, Mabou ST. An aqueous extract of Syzygium cumini protects against kainate-induced status epilepticus and amnesia: evidence for antioxidant and anti-inflammatory intervention. Metab Brain Dis 2022; 37:2581-2602. [PMID: 35916986 DOI: 10.1007/s11011-022-01052-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 07/12/2022] [Indexed: 10/16/2022]
Abstract
Temporal lobe epilepsy is the most common drug-resistant epilepsy. To cure epilepsy, drugs must target the mechanisms at the origin of seizures. Thus, the present investigation aimed to evaluate the antiepileptic- and anti-amnesic-like effects of an aqueous extract of Syzygium cumini against kainate-induced status epilepticus in mice, and possible mechanisms of action. Mice were divided into 7 groups and treated as follows: normal group or kainate group received po distilled water (10 mL/kg), four test groups received Syzygium cumini (28.8, 72, 144, and 288 mg/kg, po), and the positive control group treated intraperitoneally (ip) with sodium valproate (300 mg/kg). An extra group of normal mice was treated with piracetam (200 mg/kg, po). Treatments were administered 60 min before the induction of status epilepticus with kainate (15 mg/kg, ip), and continued daily throughout behavioral testing. Twenty-four hours after the induction, T-maze and Morris water maze tasks were successively performed. The animals were then sacrificed and some markers of oxidative stress and neuroinflammation were estimated in the hippocampus. The extract significantly prevented status epilepticus and mortality. In the T-maze, the aqueous extract markedly increased the time spent and the number of entries in the discriminated arm. In the Morris water maze, the extract significantly increased the time spent in the target quadrant during the retention phase. Furthermore, the aqueous extract induced a significant reduction of oxidative stress and neuroinflammation. These results suggest that the aqueous extract of Syzygium cumini has antiepileptic- and anti-amnesic-like effects, likely mediated in part by antioxidant and anti-inflammatory activities.
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Affiliation(s)
- Antoine Kavaye Kandeda
- Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé I, P.O. Box 812, Yaoundé, Cameroon.
- Department of Animal Biology and Physiology, University of Yaoundé I, P.O. Box 812, Yaoundé, Cameroon.
| | - Saleh Nodeina
- Department of Biological Sciences, Faculty of Science, University of Ngaoundéré, P.O. Box 454, Ngaoundéré, Cameroon
| | - Symphorien Talom Mabou
- Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé I, P.O. Box 812, Yaoundé, Cameroon
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Dohm-Hansen S, Donoso F, Lucassen PJ, Clarke G, Nolan YM. The gut microbiome and adult hippocampal neurogenesis: A new focal point for epilepsy? Neurobiol Dis 2022; 170:105746. [DOI: 10.1016/j.nbd.2022.105746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Revised: 04/13/2022] [Accepted: 04/29/2022] [Indexed: 02/07/2023] Open
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