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Song H, Mah B, Sun Y, Aloysius N, Bai Y, Zhang L. Development of spontaneous recurrent seizures accompanied with increased rates of interictal spikes and decreased hippocampal delta and theta activities following extended kindling in mice. Exp Neurol 2024; 379:114860. [PMID: 38876195 DOI: 10.1016/j.expneurol.2024.114860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 05/30/2024] [Accepted: 06/09/2024] [Indexed: 06/16/2024]
Abstract
Interictal epileptiform discharges refer to aberrant brain electrographic signals between seizures and feature intermittent interictal spikes (ISs), sharp waves, and/or abnormal rhythms. Recognition of these epileptiform activities by electroencephalographic (EEG) examinations greatly aids epilepsy diagnosis and localization of the seizure onset zone. ISs are a major form of interictal epileptiform discharges recognized in animal models of epilepsy. Progressive changes in IS waveforms, IS rates, and/or associated fast ripple oscillations have been shown to precede the development of spontaneous recurrent seizures (SRS) in various animal models. IS expressions in the kindling model of epilepsy have been demonstrated but IS changes during the course of SRS development in extended kindled animals remain to be detailed. We hence addressed this issue using a mouse model of kindling-induced SRS. Adult C57 black mice received twice daily hippocampal stimulations until SRS occurrence, with 24-h EEG monitoring performed following 50, 80, and ≥ 100 stimulations and after observation of SRS. In the stimulated hippocampus, increases in spontaneous ISs rates, but not in IS waveforms nor IS-associated fast ripples, along with decreased frequencies of hippocampal delta and theta rhythms, were observed before SRS onset. Comparable increases in IS rates were further observed in the unstimulated hippocampus, piriform cortex, and entorhinal cortex, but not in the unstimulated parietal cortex and dorsomedial thalamus. These data provide original evidence suggesting that increases in hippocampal IS rates, together with reductions in hippocampal delta and theta rhythms are closely associated with development of SRS in a rodent kindling model.
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Affiliation(s)
- Hongmei Song
- Departments of Neurosurgery, India; Krembil Research Institute, University Health Network, Canada.
| | - Bryan Mah
- Krembil Research Institute, University Health Network, Canada
| | - Yuqing Sun
- Krembil Research Institute, University Health Network, Canada
| | - Nancy Aloysius
- Krembil Research Institute, University Health Network, Canada
| | - Yang Bai
- Neuro-Oncology the First Hospital of Jilin University, China.
| | - Liang Zhang
- Krembil Research Institute, University Health Network, Canada; Division of Neurology, Department of Medicine, University of Toronto, Toronto, Ontario, Canada.
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Zhang Q, Wang Y, Wang F, Jiang D, Song Y, Yang L, Zhang M, Wang Y, Ruan Y, Fang J, Fei F. Septal stimulation attenuates hippocampal seizure with subregion specificity. Epilepsia Open 2024. [PMID: 38831626 DOI: 10.1002/epi4.12983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Revised: 05/06/2024] [Accepted: 05/18/2024] [Indexed: 06/05/2024] Open
Abstract
OBJECTIVE Deep brain stimulation (DBS) is a promising approach for the treatment of epilepsy. However, the optimal target for DBS and underlying mechanisms are still not clear. Here, we compared the therapeutic effects of DBS on distinct septal subregions, aimed to find the precise targets of septal DBS and related mechanisms for the clinical treatment. METHODS Assisted by behavioral test, electroencephalography (EEG) recording and analyzing, selectively neuronal manipulation and immunohistochemistry, we assessed the effects of DBS on the three septal subregions in kainic acid (KA)-induced mouse seizure model. RESULTS DBS in the medial septum (MS) not only delayed generalized seizure (GS) development, but reduced the severity; DBS in the vertical diagonal band of Broca (VDB) only reduced the severity of GS, while DBS in the horizontal diagonal band of Broca (HDB) subregion showed no anti-seizure effect. Notably, DBS in the MS much more efficiently decreased abnormal activation of hippocampal neurons. EEG spectrum analysis indicated that DBS in the MS and VDB subregions mainly increased the basal hippocampal low-frequency (delta and theta) rhythm. Furthermore, ablation of cholinergic neurons in the MS and VDB subregions blocked the anti-seizure and EEG-modulating effects of septal DBS, suggesting the seizure-alleviating effect of DBS was dependent on local cholinergic neurons. SIGNIFICANCE DBS in the MS and VDB, rather than HDB, attenuates hippocampal seizure by activation of cholinergic neurons-augmented hippocampal delta/theta rhythm. This may be of great therapeutic significance for the clinical treatment of epilepsy with septal DBS. PLAIN LANGUAGE SUMMARY The optical target of deep brain stimulation in the septum is still not clear. This study demonstrated that stimulation in the medial septum and vertical diagonal band of Broca subregions, but not the horizontal diagonal band of Broca, could alleviate hippocampal seizure through cholinergic neurons-augmented hippocampal delta/theta rhythm. This study may shed light on the importance of precise regulation of deep brain stimulation therapy in treating epileptic seizures.
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Affiliation(s)
- Qingyang Zhang
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, Department of Neurology, The First Affiliated Hospital, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
- Chinese Medicine Plant Essential Oil Zhejiang Engineering Research Center, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
| | - Yu Wang
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, Department of Neurology, The First Affiliated Hospital, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
| | - Fei Wang
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, Department of Neurology, The First Affiliated Hospital, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
| | - Dongxiao Jiang
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, Department of Neurology, The First Affiliated Hospital, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
| | - Yingjie Song
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, Department of Neurology, The First Affiliated Hospital, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
| | - Lin Yang
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, Department of Neurology, The First Affiliated Hospital, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
| | - Mengdi Zhang
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, Department of Neurology, The First Affiliated Hospital, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
| | - Yi Wang
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, Department of Neurology, The First Affiliated Hospital, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
- Department of Neurology, The Fourth Affiliated Hospital, School of Medicine, Zhejiang University, Yiwu, China
| | - Yeping Ruan
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, Department of Neurology, The First Affiliated Hospital, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
- Chinese Medicine Plant Essential Oil Zhejiang Engineering Research Center, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
| | - Jiajia Fang
- Department of Neurology, The Fourth Affiliated Hospital, School of Medicine, Zhejiang University, Yiwu, China
| | - Fan Fei
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, Department of Neurology, The First Affiliated Hospital, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
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3
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Kitchigina V, Shubina L. Oscillations in the dentate gyrus as a tool for the performance of the hippocampal functions: Healthy and epileptic brain. Prog Neuropsychopharmacol Biol Psychiatry 2023; 125:110759. [PMID: 37003419 DOI: 10.1016/j.pnpbp.2023.110759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2022] [Revised: 03/17/2023] [Accepted: 03/28/2023] [Indexed: 04/03/2023]
Abstract
The dentate gyrus (DG) is part of the hippocampal formation and is essential for important cognitive processes such as navigation and memory. The oscillatory activity of the DG network is believed to play a critical role in cognition. DG circuits generate theta, beta, and gamma rhythms, which participate in the specific information processing performed by DG neurons. In the temporal lobe epilepsy (TLE), cognitive abilities are impaired, which may be due to drastic alterations in the DG structure and network activity during epileptogenesis. The theta rhythm and theta coherence are especially vulnerable in dentate circuits; disturbances in DG theta oscillations and their coherence may be responsible for general cognitive impairments observed during epileptogenesis. Some researchers suggested that the vulnerability of DG mossy cells is a key factor in the genesis of TLE, but others did not support this hypothesis. The aim of the review is not only to present the current state of the art in this field of research but to help pave the way for future investigations by highlighting the gaps in our knowledge to completely appreciate the role of DG rhythms in brain functions. Disturbances in oscillatory activity of the DG during TLE development may be a diagnostic marker in the treatment of this disease.
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Affiliation(s)
- Valentina Kitchigina
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Moscow region 142290, Russia.
| | - Liubov Shubina
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Moscow region 142290, Russia
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4
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Franz J, Barheier N, Wilms H, Tulke S, Haas CA, Häussler U. Differential vulnerability of neuronal subpopulations of the subiculum in a mouse model for mesial temporal lobe epilepsy. Front Cell Neurosci 2023; 17:1142507. [PMID: 37066079 PMCID: PMC10090355 DOI: 10.3389/fncel.2023.1142507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 03/06/2023] [Indexed: 03/30/2023] Open
Abstract
Selective loss of inhibitory interneurons (INs) that promotes a shift toward an excitatory predominance may have a critical impact on the generation of epileptic activity. While research on mesial temporal lobe epilepsy (MTLE) has mostly focused on hippocampal changes, including IN loss, the subiculum as the major output region of the hippocampal formation has received less attention. The subiculum has been shown to occupy a key position in the epileptic network, but data on cellular alterations are controversial. Using the intrahippocampal kainate (KA) mouse model for MTLE, which recapitulates main features of human MTLE such as unilateral hippocampal sclerosis and granule cell dispersion, we identified cell loss in the subiculum and quantified changes in specific IN subpopulations along its dorso-ventral axis. We performed intrahippocampal recordings, FluoroJade C-staining for degenerating neurons shortly after status epilepticus (SE), fluorescence in situ hybridization for glutamic acid decarboxylase (Gad) 67 mRNA and immunohistochemistry for neuronal nuclei (NeuN), parvalbumin (PV), calretinin (CR) and neuropeptide Y (NPY) at 21 days after KA. We observed remarkable cell loss in the ipsilateral subiculum shortly after SE, reflected in lowered density of NeuN+ cells in the chronic stage when epileptic activity occurred in the subiculum concomitantly with the hippocampus. In addition, we show a position-dependent reduction of Gad67-expressing INs by ∼50% (along the dorso-ventral as well as transverse axis of the subiculum). This particularly affected the PV- and to a lesser extent CR-expressing INs. The density of NPY-positive neurons was increased, but the double-labeling for Gad67 mRNA expression revealed that an upregulation or de novo expression of NPY in non-GABAergic cells with a concomitant reduction of NPY-positive INs underlies this observation. Our data suggest a position- and cell type-specific vulnerability of subicular INs in MTLE, which might contribute to hyperexcitability of the subiculum, reflected in epileptic activity.
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Affiliation(s)
- Julia Franz
- Experimental Epilepsy Research, Department of Neurosurgery, Faculty of Medicine, Medical Center-University of Freiburg, Freiburg, Germany
| | - Nicole Barheier
- Experimental Epilepsy Research, Department of Neurosurgery, Faculty of Medicine, Medical Center-University of Freiburg, Freiburg, Germany
- Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Henrike Wilms
- Experimental Epilepsy Research, Department of Neurosurgery, Faculty of Medicine, Medical Center-University of Freiburg, Freiburg, Germany
| | - Susanne Tulke
- Experimental Epilepsy Research, Department of Neurosurgery, Faculty of Medicine, Medical Center-University of Freiburg, Freiburg, Germany
| | - Carola A. Haas
- Experimental Epilepsy Research, Department of Neurosurgery, Faculty of Medicine, Medical Center-University of Freiburg, Freiburg, Germany
- Center for Basics in NeuroModulation, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- BrainLinks-BrainTools, University of Freiburg, Freiburg, Germany
| | - Ute Häussler
- Experimental Epilepsy Research, Department of Neurosurgery, Faculty of Medicine, Medical Center-University of Freiburg, Freiburg, Germany
- BrainLinks-BrainTools, University of Freiburg, Freiburg, Germany
- *Correspondence: Ute Häussler,
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5
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Kilias A, Tulke S, Barheier N, Ruther P, Häussler U. Integration of the CA2 region in the hippocampal network during epileptogenesis. Hippocampus 2023; 33:223-240. [PMID: 36421040 DOI: 10.1002/hipo.23479] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 10/14/2022] [Accepted: 11/02/2022] [Indexed: 11/26/2022]
Abstract
The CA2 pyramidal cells are mostly resistant to cell death in mesial temporal lobe epilepsy (MTLE) with hippocampal sclerosis, but they are aberrantly integrated into the epileptic hippocampal network via mossy fiber sprouting. Furthermore, they show increased excitability in vitro in hippocampal slices obtained from human MTLE specimens or animal epilepsy models. Although these changes promote CA2 to contribute to epileptic activity (EA) in vivo, the role of CA2 in the epileptic network within and beyond the sclerotic hippocampus is still unclear. We used the intrahippocampal kainate mouse model for MTLE, which recapitulates most features of the human disease including pharmacoresistant epileptic seizures and hippocampal sclerosis, with preservation of dentate gyrus (DG) granule cells and CA2 pyramidal cells. In vivo recordings with electrodes in CA2 and the DG showed that EA occurs at high coincidence between the ipsilateral DG and CA2 and current source density analysis of silicon probe recordings in dorsal ipsilateral CA2 revealed CA2 as a local source of EA. Cell-specific viral tracing in Amigo2-icreERT2 mice confirmed the preservation of the axonal projection from ipsilateral CA2 pyramidal cells to contralateral CA2 under epileptic conditions and indeed, EA propagated from ipsi- to contralateral CA2 with increasing likelihood with time after KA injection, but always at lower intensity than within the ipsilateral hippocampus. Furthermore, we show that CA2 presents with local theta oscillations and like the DG, shows a pathological reduction of theta frequency already from 2 days after KA onward. The early changes in activity might be facilitated by the loss of glutamic acid decarboxylase 67 (Gad67) mRNA-expressing interneurons directly after the initial status epilepticus in ipsi- but not contralateral CA2. Together, our data highlight CA2 as an active player in the epileptic network and with its contralateral connections as one possible router of aberrant activity.
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Affiliation(s)
- Antje Kilias
- Institute for Physiology I, Medical Faculty, University of Freiburg, Freiburg, Germany
| | - Susanne Tulke
- Experimental Epilepsy Research, Department of Neurosurgery, Medical Center - University of Freiburg, Faculty of Medicine, Freiburg, Germany
| | - Nicole Barheier
- Experimental Epilepsy Research, Department of Neurosurgery, Medical Center - University of Freiburg, Faculty of Medicine, Freiburg, Germany.,Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Patrick Ruther
- Microsystem Materials Laboratory, Department of Microsystems Engineering (IMTEK), University of Freiburg, Freiburg, Germany.,Center BrainLinks-BrainTools, University of Freiburg, Freiburg, Germany
| | - Ute Häussler
- Experimental Epilepsy Research, Department of Neurosurgery, Medical Center - University of Freiburg, Faculty of Medicine, Freiburg, Germany.,Center BrainLinks-BrainTools, University of Freiburg, Freiburg, Germany
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6
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Pototskiy E, Dellinger JR, Bumgarner S, Patel J, Sherrerd-Smith W, Musto AE. Brain injuries can set up an epileptogenic neuronal network. Neurosci Biobehav Rev 2021; 129:351-366. [PMID: 34384843 DOI: 10.1016/j.neubiorev.2021.08.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2021] [Accepted: 08/01/2021] [Indexed: 10/20/2022]
Abstract
Development of epilepsy or epileptogenesis promotes recurrent seizures. As of today, there are no effective prophylactic therapies to prevent the onset of epilepsy. Contributing to this deficiency of preventive therapy is the lack of clarity in fundamental neurobiological mechanisms underlying epileptogenesis and lack of reliable biomarkers to identify patients at risk for developing epilepsy. This limits the development of prophylactic therapies in epilepsy. Here, neural network dysfunctions reflected by oscillopathies and microepileptiform activities, including neuronal hyperexcitability and hypersynchrony, drawn from both clinical and experimental epilepsy models, have been reviewed. This review suggests that epileptogenesis reflects a progressive and dynamic dysfunction of specific neuronal networks which recruit further interconnected groups of neurons, with this resultant pathological network mediating seizure occurrence, recurrence, and progression. In the future, combining spatial and temporal resolution of neuronal non-invasive recordings from patients at risk of developing epilepsy, together with analytics and computational tools, may contribute to determining whether the brain is undergoing epileptogenesis in asymptomatic patients following brain injury.
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Affiliation(s)
- Esther Pototskiy
- Department of Anatomy & Pathology, Eastern Virginia Medical School, Department of Pathology, Norfolk, Virginia, USA; College of Sciences, Old Dominion University, Norfolk, Virginia
| | - Joshua Ryan Dellinger
- Department of Anatomy & Pathology, Eastern Virginia Medical School, Department of Pathology, Norfolk, Virginia, USA
| | - Stuart Bumgarner
- Department of Anatomy & Pathology, Eastern Virginia Medical School, Department of Pathology, Norfolk, Virginia, USA
| | - Jay Patel
- Department of Anatomy & Pathology, Eastern Virginia Medical School, Department of Pathology, Norfolk, Virginia, USA
| | - William Sherrerd-Smith
- Department of Anatomy & Pathology, Eastern Virginia Medical School, Department of Pathology, Norfolk, Virginia, USA
| | - Alberto E Musto
- Department of Anatomy & Pathology, Eastern Virginia Medical School, Department of Pathology, Norfolk, Virginia, USA; Department of Neurology, Eastern Virginia Medical School, Department of Pathology, Norfolk, Virginia, USA.
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7
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Zhen ZH, Guo MR, Li HM, Guo OY, Zhen JL, Fu J, Tan GJ. Normal and Abnormal Sharp Wave Ripples in the Hippocampal-Entorhinal Cortex System: Implications for Memory Consolidation, Alzheimer's Disease, and Temporal Lobe Epilepsy. Front Aging Neurosci 2021; 13:683483. [PMID: 34262446 PMCID: PMC8273653 DOI: 10.3389/fnagi.2021.683483] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Accepted: 06/01/2021] [Indexed: 12/14/2022] Open
Abstract
The appearance of hippocampal sharp wave ripples (SWRs) is an electrophysiological biomarker for episodic memory encoding and behavioral planning. Disturbed SWRs are considered a sign of neural network dysfunction that may provide insights into the structural connectivity changes associated with cognitive impairment in early-stage Alzheimer's disease (AD) and temporal lobe epilepsy (TLE). SWRs originating from hippocampus have been extensively studied during spatial navigation in rodents, and more recent studies have investigated SWRs in the hippocampal-entorhinal cortex (HPC-EC) system during a variety of other memory-guided behaviors. Understanding how SWR disruption impairs memory function, especially episodic memory, could aid in the development of more efficacious therapeutics for AD and TLE. In this review, we first provide an overview of the reciprocal association between AD and TLE, and then focus on the functions of HPC-EC system SWRs in episodic memory consolidation. It is posited that these waveforms reflect rapid network interactions among excitatory projection neurons and local interneurons and that these waves may contribute to synaptic plasticity underlying memory consolidation. Further, SWRs appear altered or ectopic in AD and TLE. These waveforms may thus provide clues to understanding disease pathogenesis and may even serve as biomarkers for early-stage disease progression and treatment response.
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Affiliation(s)
- Zhi-Hang Zhen
- Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, China
| | - Mo-Ran Guo
- Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, China.,Neurological Laboratory of Hebei Province, Shijiazhuang, China
| | - He-Ming Li
- Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, China
| | - Ou-Yang Guo
- Department of Biology, Boston University, Boston, MA, United States
| | - Jun-Li Zhen
- Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, China.,Neurological Laboratory of Hebei Province, Shijiazhuang, China
| | - Jian Fu
- Department of Emergency Surgery, The Second Hospital of Hebei Medical University, Shijiazhuang, China
| | - Guo-Jun Tan
- Department of Neurology, The Second Hospital of Hebei Medical University, Shijiazhuang, China.,Neurological Laboratory of Hebei Province, Shijiazhuang, China
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8
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Vera J, Lippmann K. Post-stroke epileptogenesis is associated with altered intrinsic properties of hippocampal pyramidal neurons leading to increased theta resonance. Neurobiol Dis 2021; 156:105425. [PMID: 34119635 DOI: 10.1016/j.nbd.2021.105425] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 06/01/2021] [Accepted: 06/08/2021] [Indexed: 01/23/2023] Open
Abstract
Brain insults like stroke, trauma or infections often lead to blood-brain barrier-dysfunction (BBBd) frequently resulting into epileptogenesis. Affected patients suffer from seizures and cognitive comorbidities that are potentially linked to altered network oscillations. It has been shown that a hippocampal BBBd in rats leads to in vivo seizures and increased power at theta (3-8 Hz), an important type of network oscillations. However, the underlying cellular mechanisms remain poorly understood. At membrane potentials close to the threshold for action potentials (APs) a subpopulation of CA1 pyramidal cells (PCs) displays intrinsic resonant properties due to an interplay of the muscarine-sensitive K+-current (IM) and the persistent Na+-current (INaP). Such resonant neurons are more excitable and generate more APs when stimulated at theta frequencies, being strong candidates for contributing to hippocampal theta oscillations during epileptogenesis. We tested this hypothesis by characterizing changes in intrinsic properties of hippocampal PCs one week after post-stroke epileptogenesis, a model associated with BBBd, using slice electrophysiology and computer modeling. We find a higher proportion of resonant neurons in BBBd compared to sham animals (47 vs. 29%), accompanied by an increase in their excitability. In contrast, BBBd non-resonant neurons showed a reduced excitability, presented with lower impedance and more positive AP threshold. We identify an increase in IM combined with either a reduction in INaP or an increase in ILeak as possible mechanisms underlying the observed changes. Our results support the hypothesis that a higher proportion of more excitable resonant neurons in the hippocampus contributes to increased theta oscillations and an increased likelihood of seizures in a model of post-stroke epileptogenesis.
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Affiliation(s)
- Jorge Vera
- Grass Laboratory, Marine Biological Laboratory, Woods Hole, MA 02543, USA; Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Kristina Lippmann
- Grass Laboratory, Marine Biological Laboratory, Woods Hole, MA 02543, USA; Carl-Ludwig-Institute for Physiology, Medical Faculty, University of Leipzig, D-04103 Leipzig, Germany.
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9
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Wang Y, Shen Y, Cai X, Yu J, Chen C, Tan B, Tan N, Cheng H, Fan X, Wu X, Liu J, Wang S, Wang Y, Chen Z. Deep brain stimulation in the medial septum attenuates temporal lobe epilepsy via entrainment of hippocampal theta rhythm. CNS Neurosci Ther 2021; 27:577-586. [PMID: 33502829 PMCID: PMC8025637 DOI: 10.1111/cns.13617] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 01/10/2021] [Accepted: 01/12/2021] [Indexed: 12/13/2022] Open
Abstract
Aims Temporal lobe epilepsy (TLE), often associated with cognitive impairment, is one of the most common types of medically refractory epilepsy. Deep brain stimulation (DBS) shows considerable promise for the treatment of TLE. However, the optimal stimulation targets and parameters of DBS to control seizures and related cognitive impairment are still not fully illustrated. Methods In the present study, we evaluated the therapeutic potential of DBS in the medial septum (MS) on seizures and cognitive function in mouse acute and chronic epilepsy models. Results We found that DBS in the MS alleviated the severity of seizure activities in both kainic acid‐induced acute seizure model and hippocampal‐kindled epilepsy model. DBS showed antiseizure effects with a wide window of effective stimulation frequencies. The antiseizure effects of DBS were mediated by the hippocampal theta rhythm, as atropine, which reversed the DBS‐induced augmentation of the hippocampal theta oscillation, abolished the antiseizure effects of DBS. Further, in the kainic acid‐induced chronic TLE model, DBS in the MS not only reduced spontaneous seizures, but also improved behavioral performance in novel object recognition. Conclusion DBS in the MS is a promising approach to attenuate TLE probably through entrainment of the hippocampal theta rhythm, which may be therapeutically significant for refractory TLE treatment.
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Affiliation(s)
- Ying Wang
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, College of Pharmaceutical Science, Zhejiang Chinese Medical University, Hangzhou, China.,Institute of Pharmacology and Toxicology, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
| | - Yating Shen
- Institute of Pharmacology and Toxicology, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
| | - Xianhui Cai
- Institute of Pharmacology and Toxicology, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
| | - Jie Yu
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, College of Pharmaceutical Science, Zhejiang Chinese Medical University, Hangzhou, China
| | - Cong Chen
- Epilepsy Center, School of Medicine, Second Affiliated Hospital, Zhejiang University, Hangzhou, China
| | - Bei Tan
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, College of Pharmaceutical Science, Zhejiang Chinese Medical University, Hangzhou, China
| | - Na Tan
- Institute of Pharmacology and Toxicology, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
| | - Heming Cheng
- Institute of Pharmacology and Toxicology, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
| | - Xiang Fan
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, College of Pharmaceutical Science, Zhejiang Chinese Medical University, Hangzhou, China
| | - Xiaohua Wu
- Epilepsy Center, School of Medicine, Second Affiliated Hospital, Zhejiang University, Hangzhou, China
| | - Jinggen Liu
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, College of Pharmaceutical Science, Zhejiang Chinese Medical University, Hangzhou, China
| | - Shuang Wang
- Epilepsy Center, School of Medicine, Second Affiliated Hospital, Zhejiang University, Hangzhou, China
| | - Yi Wang
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, College of Pharmaceutical Science, Zhejiang Chinese Medical University, Hangzhou, China.,Institute of Pharmacology and Toxicology, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
| | - Zhong Chen
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, College of Pharmaceutical Science, Zhejiang Chinese Medical University, Hangzhou, China.,Institute of Pharmacology and Toxicology, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China.,Epilepsy Center, School of Medicine, Second Affiliated Hospital, Zhejiang University, Hangzhou, China
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10
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Impaired θ-γ Coupling Indicates Inhibitory Dysfunction and Seizure Risk in a Dravet Syndrome Mouse Model. J Neurosci 2020; 41:524-537. [PMID: 33234612 DOI: 10.1523/jneurosci.2132-20.2020] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 10/02/2020] [Accepted: 11/12/2020] [Indexed: 01/24/2023] Open
Abstract
Dravet syndrome (DS) is an epileptic encephalopathy that still lacks biomarkers for epileptogenesis and its treatment. Dysfunction of NaV1.1 sodium channels, which are chiefly expressed in inhibitory interneurons, explains the epileptic phenotype. Understanding the network effects of these cellular deficits may help predict epileptogenesis. Here, we studied θ-γ coupling as a potential marker for altered inhibitory functioning and epileptogenesis in a DS mouse model. We found that cortical θ-γ coupling was reduced in both male and female juvenile DS mice and persisted only if spontaneous seizures occurred. θ-γ Coupling was partly restored by cannabidiol (CBD). Locally disrupting NaV1.1 expression in the hippocampus or cortex yielded early attenuation of θ-γ coupling, which in the hippocampus associated with fast ripples, and which was replicated in a computational model when voltage-gated sodium currents were impaired in basket cells (BCs). Our results indicate attenuated θ-γ coupling as a promising early indicator of inhibitory dysfunction and seizure risk in DS.
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11
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Li J, Leverton LK, Naganatanahalli LM, Christian-Hinman CA. Seizure burden fluctuates with the female reproductive cycle in a mouse model of chronic temporal lobe epilepsy. Exp Neurol 2020; 334:113492. [PMID: 33007292 DOI: 10.1016/j.expneurol.2020.113492] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 09/22/2020] [Accepted: 09/28/2020] [Indexed: 12/30/2022]
Abstract
Women with catamenial epilepsy often experience increased seizure burden near the time of ovulation (periovulatory) or menstruation (perimenstrual). To date, a rodent model of chronic temporal lobe epilepsy (TLE) that exhibits similar endogenous fluctuations in seizures has not been identified. Here, we investigated whether seizure burden changes with the estrous cycle in the intrahippocampal kainic acid (IHKA) mouse model of TLE. Adult female IHKA mice and saline-injected controls were implanted with EEG electrodes in the ipsilateral hippocampus. At one and two months post-injection, 24/7 video-EEG recordings were collected and estrous cycle stage was assessed daily. Seizures were detected using a custom convolutional neural network machine learning process. Seizure burden was compared within each mouse between diestrus and combined proestrus and estrus days (pro/estrus) at two months post-injection. IHKA mice showed higher seizure burden on pro/estrus compared with diestrus, characterized by increased time in seizures and longer seizure duration. When all IHKA mice were included, no group differences were observed in seizure frequency or EEG power. However, increased baseline seizure burden on diestrus was correlated with larger cycle-associated differences, and when analyses were restricted to mice that showed the severe epilepsy typical of the IHKA model, increased seizure frequency on pro/estrus was also revealed. Controls showed no differences in EEG parameters with cycle stage. These results suggest that the stages of proestrus and estrus are associated with higher seizure burden in IHKA mice. The IHKA model may thus recapitulate at least some aspects of reproductive cycle-associated seizure clustering.
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Affiliation(s)
- Jiang Li
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Leanna K Leverton
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Laxmi Manisha Naganatanahalli
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Catherine A Christian-Hinman
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
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12
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Xing H, Xu S, Xie X, Wang Y, Lu C, Han X. Levetiracetam induction of theta frequency oscillations in rodent hippocampus in vitro. Can J Physiol Pharmacol 2020; 98:725-732. [PMID: 32516556 DOI: 10.1139/cjpp-2019-0727] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Levetiracetam (LEV) has been demonstrated to improve cognitive function. Hippocampal theta rhythm (4-12 Hz) is associated with a variety of cognitively related behaviors, such as exploration in both humans and animal models. We investigated the effects of LEV on the theta rhythm in the rat hippocampal CA3 in hippocampal slices in vitro. We found that LEV increased the theta power in a dose-dependent manner. The increase in theta power can be blocked by GABAA receptor (GABAAR) or NMDA receptor (NMDAR) antagonists but not by AMPA receptor antagonist, indicating the involvement of GABAAR and NMDAR in the induction of theta activity. Interestingly, LEV enhancement of theta power can be also blocked by taurine or GABA-A agonist THIP, indicating that LEV induction of theta may be related to the indirect boosting of GABA action via reduction of extrasynaptic GABAAR activation. Furthermore, the increased theta power can be partially reduced by the mACh receptor (mAChR) antagonist atropine but not by nACh receptor antagonists, suggesting that mAChR activation provides excitatory input into local network responsible for LEV-induced theta. Our study demonstrated that LEV induced a novel theta oscillation in vitro, which may have implications in the treatment of the neuronal disorders with impaired theta oscillation and cognitive function.
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Affiliation(s)
- Hang Xing
- Key Lab of Brain Research of Henan Province, Department of Physiology and Neurobiology, Xinxiang Medical University, Henan, 453000, P.R. China.,Department of Neurology, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, Zhengzhou, Henan, 450000, P.R. China
| | - Sihan Xu
- Key Lab of Brain Research of Henan Province, Department of Physiology and Neurobiology, Xinxiang Medical University, Henan, 453000, P.R. China
| | - Xin'e Xie
- Key Lab of Brain Research of Henan Province, Department of Physiology and Neurobiology, Xinxiang Medical University, Henan, 453000, P.R. China
| | - Yuan Wang
- Key Lab of Brain Research of Henan Province, Department of Physiology and Neurobiology, Xinxiang Medical University, Henan, 453000, P.R. China
| | - Chengbiao Lu
- Key Lab of Brain Research of Henan Province, Department of Physiology and Neurobiology, Xinxiang Medical University, Henan, 453000, P.R. China
| | - Xiong Han
- Department of Neurology, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, Zhengzhou, Henan, 450000, P.R. China
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13
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Boehler C, Vieira DM, Egert U, Asplund M. NanoPt-A Nanostructured Electrode Coating for Neural Recording and Microstimulation. ACS APPLIED MATERIALS & INTERFACES 2020; 12:14855-14865. [PMID: 32162910 DOI: 10.1021/acsami.9b22798] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Bioelectronic devices, interfacing neural tissue for therapeutic, diagnostic, or rehabilitation purposes, rely on small electrode contacts in order to achieve highly sophisticated communication at the neural interface. Reliable recording and safe stimulation with small electrodes, however, are limited when conventional electrode metallizations are used, demanding the development of new materials to enable future progress within bioelectronics. In this study, we present a versatile process for the realization of nanostructured platinum (nanoPt) coatings with a high electrochemically active surface area, showing promising biocompatibility and providing low impedance, high charge injection capacity, and outstanding long-term stability both for recording and stimulation. The proposed electrochemical fabrication process offers exceptional control over the nanoPt deposition, allowing the realization of specific coating morphologies such as small grains, pyramids, or nanoflakes, and can moreover be scaled up to wafer level or batch fabrication under economic process conditions. The suitability of nanoPt as a coating for neural interfaces is here demonstrated, in vitro and in vivo, revealing superior stimulation performance under chronic conditions. Thus, nanoPt offers promising qualities as an advanced neural interface coating which moreover extends to the numerous application fields where a large (electro)chemically active surface area contributes to increased efficiency.
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Affiliation(s)
- Christian Boehler
- Department of Microsystems Engineering (IMTEK)-ElectroActive Coatings Group, University of Freiburg, Georges-Koehler-Allee 102, 79110 Freiburg, Germany
- BrainLinks-BrainTools Center, University of Freiburg, 79110 Freiburg, Germany
| | - Diego M Vieira
- BrainLinks-BrainTools Center, University of Freiburg, 79110 Freiburg, Germany
- Department of Microsystems Engineering (IMTEK)-Laboratory for Biomicrotechnology, University of Freiburg, Georges-Koehler-Allee 102, 79110 Freiburg, Germany
- Bernstein Center Freiburg (BCF), University of Freiburg, 79110 Freiburg, Germany
| | - Ulrich Egert
- BrainLinks-BrainTools Center, University of Freiburg, 79110 Freiburg, Germany
- Department of Microsystems Engineering (IMTEK)-Laboratory for Biomicrotechnology, University of Freiburg, Georges-Koehler-Allee 102, 79110 Freiburg, Germany
- Bernstein Center Freiburg (BCF), University of Freiburg, 79110 Freiburg, Germany
| | - Maria Asplund
- Department of Microsystems Engineering (IMTEK)-ElectroActive Coatings Group, University of Freiburg, Georges-Koehler-Allee 102, 79110 Freiburg, Germany
- BrainLinks-BrainTools Center, University of Freiburg, 79110 Freiburg, Germany
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14
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Chauvière L. Update on temporal lobe‐dependent information processing, in health and disease. Eur J Neurosci 2019; 51:2159-2204. [DOI: 10.1111/ejn.14594] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 09/06/2019] [Accepted: 09/27/2019] [Indexed: 01/29/2023]
Affiliation(s)
- Laëtitia Chauvière
- INSERM U1266 Institut de Psychiatrie et de Neurosciences de Paris (IPNP) Paris France
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15
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Peng S, Yang J, Wang Y, Fan Y, Tang F, Hou C, Yu J, Wang X, Jiang G. Low-dose intranasal insulin improves cognitive function and suppresses the development of epilepsy. Brain Res 2019; 1726:146474. [PMID: 31557476 DOI: 10.1016/j.brainres.2019.146474] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 09/20/2019] [Accepted: 09/22/2019] [Indexed: 01/19/2023]
Abstract
Intranasal insulin exerts neuroprotective effects in a variety of neurological diseases. Whether intranasal insulin affects epileptic activity and whether it has neuroprotective effects in epileptic diseases is however still unknown. In this study we show that low-dose intranasal insulin inhibited kainic acid (KA)- or pentylenetetrazole (PTZ)-induced acute seizures and reduced epileptic discharge activities in mice, potentially by alleviating the increase in seizure-induced glutamate in the hippocampus. Meanwhile, intranasal insulin increased GABA levels and the activities of hippocampal theta, which may affect the excitability of the hippocampus. In chronic KA-induced epilepsy, low-dose intranasal insulin reduces the frequency of spontaneous recurrent seizures and epileptic discharges, while it increases theta energy and thereby improves spatial memory. Larger doses of intranasal insulin increased the frequency of seizures but did not aggravate cognitive impairment, suggesting that the frequency of seizures may not be related to impaired cognitive function. Overall, our findings show that low-dose intranasal insulin inhibits epileptic events and improves cognitive impairment in epileptic mice, suggesting that learning and memory can be improved by intranasal insulin. However, larger doses might increase the risk of epileptic seizures.
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Affiliation(s)
- Shu Peng
- Department of Neurology, Affiliated Hospital of North Sichuan Medical College, 63 Wenhua Road, Nanchong 637000, China; Institute of Neurological Diseases, North Sichuan Medical College, 234 Fujiang Road, Nanchong, Sichuan, China
| | - Jin Yang
- Department of Neurology, Affiliated Hospital of North Sichuan Medical College, 63 Wenhua Road, Nanchong 637000, China; Institute of Neurological Diseases, North Sichuan Medical College, 234 Fujiang Road, Nanchong, Sichuan, China
| | - Yufeng Wang
- Department of Neurology, Affiliated Hospital of North Sichuan Medical College, 63 Wenhua Road, Nanchong 637000, China; Institute of Neurological Diseases, North Sichuan Medical College, 234 Fujiang Road, Nanchong, Sichuan, China
| | - Yang Fan
- Department of Neurology, Affiliated Hospital of North Sichuan Medical College, 63 Wenhua Road, Nanchong 637000, China; Institute of Neurological Diseases, North Sichuan Medical College, 234 Fujiang Road, Nanchong, Sichuan, China
| | - Feng Tang
- Department of Neurology, Affiliated Hospital of North Sichuan Medical College, 63 Wenhua Road, Nanchong 637000, China; Institute of Neurological Diseases, North Sichuan Medical College, 234 Fujiang Road, Nanchong, Sichuan, China
| | - Changyue Hou
- Department of Neurology, Affiliated Hospital of North Sichuan Medical College, 63 Wenhua Road, Nanchong 637000, China; Institute of Neurological Diseases, North Sichuan Medical College, 234 Fujiang Road, Nanchong, Sichuan, China
| | - Juming Yu
- Department of Neurology, Affiliated Hospital of North Sichuan Medical College, 63 Wenhua Road, Nanchong 637000, China; Institute of Neurological Diseases, North Sichuan Medical College, 234 Fujiang Road, Nanchong, Sichuan, China
| | - Xiaoming Wang
- Department of Neurology, Affiliated Hospital of North Sichuan Medical College, 63 Wenhua Road, Nanchong 637000, China; Institute of Neurological Diseases, North Sichuan Medical College, 234 Fujiang Road, Nanchong, Sichuan, China.
| | - Guohui Jiang
- Department of Neurology, Affiliated Hospital of North Sichuan Medical College, 63 Wenhua Road, Nanchong 637000, China; Institute of Neurological Diseases, North Sichuan Medical College, 234 Fujiang Road, Nanchong, Sichuan, China.
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16
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Bursts with High and Low Load of Epileptiform Spikes Show Context-Dependent Correlations in Epileptic Mice. eNeuro 2019; 6:ENEURO.0299-18.2019. [PMID: 31420348 PMCID: PMC6731539 DOI: 10.1523/eneuro.0299-18.2019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 06/12/2019] [Accepted: 06/27/2019] [Indexed: 12/15/2022] Open
Abstract
Hypersynchronous network activity is the defining hallmark of epilepsy and manifests in a wide spectrum of phenomena, of which electrographic activity during seizures is only one extreme. The aim of this study was to differentiate between different types of epileptiform activity (EA) patterns and investigate their temporal succession and interactions. We analyzed local field potentials (LFPs) from freely behaving male mice that had received an intrahippocampal kainate injection to model mesial temporal lobe epilepsy (MTLE). Epileptiform spikes occurred in distinct bursts. Using machine learning, we derived a scale reflecting the spike load of bursts and three main burst categories that we labeled high-load, medium-load, and low-load bursts. We found that bursts of these categories were non-randomly distributed in time. High-load bursts formed clusters and were typically surrounded by transition phases with increased rates of medium-load and low-load bursts. In apparent contradiction to this, increased rates of low-load bursts were also associated with longer background phases, i.e., periods lacking high-load bursting. Furthermore, the rate of low-load bursts was more strongly correlated with the duration of background phases than the overall rate of epileptiform spikes. Our findings are consistent with the hypothesis that low-level EA could promote network stability but could also participate in transitions towards major epileptiform events, depending on the current state of the network.
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17
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Tulke S, Haas CA, Häussler U. Expression of brain‐derived neurotrophic factor and structural plasticity in the dentate gyrus and
CA
2 region correlate with epileptiform activity. Epilepsia 2019; 60:1234-1247. [DOI: 10.1111/epi.15540] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 04/17/2019] [Accepted: 04/22/2019] [Indexed: 01/29/2023]
Affiliation(s)
- Susanne Tulke
- Experimental Epilepsy Research Department of Neurosurgery Medical Center - University of Freiburg Faculty of Medicine University of Freiburg Freiburg im Breisgau Germany
- Faculty of Biology University of Freiburg Freiburg im Breisgau Germany
| | - Carola A. Haas
- Experimental Epilepsy Research Department of Neurosurgery Medical Center - University of Freiburg Faculty of Medicine University of Freiburg Freiburg im Breisgau Germany
- BrainLinks‐BrainTools Cluster of Excellence University of Freiburg Freiburg im Breisgau Germany
| | - Ute Häussler
- Experimental Epilepsy Research Department of Neurosurgery Medical Center - University of Freiburg Faculty of Medicine University of Freiburg Freiburg im Breisgau Germany
- BrainLinks‐BrainTools Cluster of Excellence University of Freiburg Freiburg im Breisgau Germany
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18
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Jiang G, Pu T, Li Z, Zhang X, Zhou R, Cao X, Yu J, Wang X. Lithium affects rat hippocampal electrophysiology and epileptic seizures in a dose dependent manner. Epilepsy Res 2018; 146:112-120. [DOI: 10.1016/j.eplepsyres.2018.07.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 07/20/2018] [Accepted: 07/27/2018] [Indexed: 12/14/2022]
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19
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Kilias A, Canales A, Froriep UP, Park S, Egert U, Anikeeva P. Optogenetic entrainment of neural oscillations with hybrid fiber probes. J Neural Eng 2018; 15:056006. [PMID: 29923505 PMCID: PMC6125198 DOI: 10.1088/1741-2552/aacdb9] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
OBJECTIVE Optogenetic modulation of neural activity is a ubiquitous tool for basic investigation of brain circuits. While the majority of optogenetic paradigms rely on short light pulses to evoke synchronized activity of optically sensitized cells, many neurobiological processes are associated with slow local field potential (LFP) oscillations. Therefore, we developed a hybrid fiber probe capable of simultaneous electrophysiological recording and optical stimulation and used it to investigate the utility of sinusoidal light stimulation for evoking oscillatory neural activity in vivo across a broad frequency range. APPROACH We fabricated hybrid fiber probes comprising a hollow cylindrical array of 9 electrodes and a flexible optical waveguide integrated within the core. We implanted these probes in the hippocampus of transgenic Thy1-ChR2-YFP mice that broadly express the blue-light sensitive cation channel channelrhodopsin 2 (ChR2) in excitatory neurons across the brain. The effects of the sinusoidal light stimulation were characterized and contrasted with those corresponding to pulsed stimulation in the frequency range of physiological LFP rhythms (3-128 Hz). MAIN RESULTS Within hybrid probes, metal electrode surfaces were vertically aligned with the waveguide tip, which minimized optical stimulation artifacts in neurophysiological recordings. Sinusoidal stimulation resulted in reliable and coherent entrainment of LFP oscillations up to 70 Hz, the cutoff frequency of ChR2, with response amplitudes inversely scaling with the stimulation frequencies. Effectiveness of the stimulation was maintained for two months following implantation. SIGNIFICANCE Alternative stimulation patterns complementing existing pulsed protocols, in particular sinusoidal light stimulation, are a prerequisite for investigating the physiological mechanisms underlying brain rhythms. So far, studies applying sinusoidal stimulation in vivo were limited to single stimulation frequencies. We show the feasibility of sinusoidal stimulation in vivo to induce coherent LFP oscillations across the entire frequency spectrum supported by the gating dynamics of ChR2 and introduce a hybrid fiber probe tailored to continuous light stimulation.
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Affiliation(s)
- Antje Kilias
- Bernstein Center Freiburg, University of Freiburg, Freiburg, Germany
- Biomicrotechnology, Institute for Microsystems Engineering, University of Freiburg, Freiburg, Germany
- Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Andres Canales
- Department of Materials Science and Engineering, and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Ulrich P. Froriep
- Department of Materials Science and Engineering, and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
- Simons Center for the Social Brain, Massachusetts Institute of Technology, Hannover, Germany
- Fraunhofer Institute for Toxicology and Experimental Medicine, Hannover, Germany
| | - Seongjun Park
- Department of Electrical Engineering and Computer Science, and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Ulrich Egert
- Bernstein Center Freiburg, University of Freiburg, Freiburg, Germany
- Biomicrotechnology, Institute for Microsystems Engineering, University of Freiburg, Freiburg, Germany
| | - Polina Anikeeva
- Department of Materials Science and Engineering, and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
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