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Trofimova AM, Amakhin DV, Postnikova TY, Tiselko VS, Alekseev A, Podoliak E, Gordeliy VI, Chizhov AV, Zaitsev AV. Light-Driven Sodium Pump as a Potential Tool for the Control of Seizures in Epilepsy. Mol Neurobiol 2024; 61:4691-4704. [PMID: 38114761 DOI: 10.1007/s12035-023-03865-z] [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: 08/12/2023] [Accepted: 12/06/2023] [Indexed: 12/21/2023]
Abstract
The marine flavobacterium Krokinobactereikastus light-driven sodium pump (KR2) generates an outward sodium ion current under 530 nm light stimulation, representing a promising optogenetic tool for seizure control. However, the specifics of KR2 application to suppress epileptic activity have not yet been addressed. In the present study, we investigated the possibility of KR2 photostimulation to suppress epileptiform activity in mouse brain slices using the 4-aminopyrindine (4-AP) model. We injected the adeno-associated viral vector (AAV-PHP.eB-hSyn-KR2-YFP) containing the KR2 sodium pump gene enhanced with appropriate trafficking tags. KR2 expression was observed in the lateral entorhinal cortex and CA1 hippocampus. Using whole-cell patch clamp in mouse brain slices, we show that KR2, when stimulated with LED light, induces a substantial hyperpolarization of entorhinal neurons. However, continuous photostimulation of KR2 does not interrupt ictal discharges in mouse entorhinal cortex slices induced by a solution containing 4-AP. KR2-induced hyperpolarization strongly activates neuronal HCN channels. Consequently, turning off photostimulation resulted in HCN channel-mediated rebound depolarization accompanied by a transient increase in spontaneous network activity. Using low-frequency pulsed photostimulation, we induced the generation of short HCN channel-mediated discharges that occurred in response to the light stimulus being turned off; these discharges reliably interrupt ictal activity. Thus, low-frequency pulsed photostimulation of KR2 can be considered as a potential tool for controlling epileptic seizures.
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Affiliation(s)
- Alina M Trofimova
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Saint Petersburg, Russia
| | - Dmitry V Amakhin
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Saint Petersburg, Russia
| | - Tatyana Y Postnikova
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Saint Petersburg, Russia
| | - Vasilii S Tiselko
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Saint Petersburg, Russia
| | - Alexey Alekseev
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology (National Research University), Dolgoprudny, Russia
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
| | - Elizaveta Podoliak
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology (National Research University), Dolgoprudny, Russia
- Department of Ophthalmology, Universitäts-Augenklinik Bonn, University of Bonn, Bonn, Germany
| | - Valentin I Gordeliy
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology (National Research University), Dolgoprudny, Russia
- Institut de Biologie Structurale (IBS), Université Grenoble Alpes, CEA, CNRS, Grenoble, France
| | - Anton V Chizhov
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Saint Petersburg, Russia
- MathNeuro Team, Inria Centre at Université Côte d'Azur, Sophia Antipolis, France
| | - Aleksey V Zaitsev
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Saint Petersburg, Russia.
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Capitano F, Kuchenbuch M, Lavigne J, Chaptoukaev H, Zuluaga MA, Lorenzi M, Nabbout R, Mantegazza M. Preictal dysfunctions of inhibitory interneurons paradoxically lead to their rebound hyperactivity and to low-voltage-fast onset seizures in Dravet syndrome. Proc Natl Acad Sci U S A 2024; 121:e2316364121. [PMID: 38809712 PMCID: PMC11161744 DOI: 10.1073/pnas.2316364121] [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: 09/26/2023] [Accepted: 05/01/2024] [Indexed: 05/31/2024] Open
Abstract
Epilepsies have numerous specific mechanisms. The understanding of neural dynamics leading to seizures is important for disclosing pathological mechanisms and developing therapeutic approaches. We investigated electrographic activities and neural dynamics leading to convulsive seizures in patients and mouse models of Dravet syndrome (DS), a developmental and epileptic encephalopathy in which hypoexcitability of GABAergic neurons is considered to be the main dysfunction. We analyzed EEGs from DS patients carrying a SCN1A pathogenic variant, as well as epidural electrocorticograms, hippocampal local field potentials, and hippocampal single-unit neuronal activities in Scn1a+/- and Scn1aRH/+ DS mice. Strikingly, most seizures had low-voltage-fast onset in both patients and mice, which is thought to be generated by hyperactivity of GABAergic interneurons, the opposite of the main pathological mechanism of DS. Analyzing single-unit recordings, we observed that temporal disorganization of the firing of putative interneurons in the period immediately before the seizure (preictal) precedes the increase of their activity at seizure onset, together with the entire neuronal network. Moreover, we found early signatures of the preictal period in the spectral features of hippocampal and cortical field potential of Scn1a mice and of patients' EEG, which are consistent with the dysfunctions that we observed in single neurons and that allowed seizure prediction. Therefore, the perturbed preictal activity of interneurons leads to their hyperactivity at the onset of generalized seizures, which have low-voltage-fast features that are similar to those observed in other epilepsies and are triggered by hyperactivity of GABAergic neurons. Preictal spectral features may be used as predictive seizure biomarkers.
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Affiliation(s)
- Fabrizio Capitano
- University Cote d’Azur, Institute of Molecular and Cellular Pharmacology, Valbonne-Sophia Antipolis06560, France
- CNRS UMR 7275, Valbonne-Sophia Antipolis06560, France
- Inserm U1323, Valbonne-Sophia Antipolis06650, France
| | - Mathieu Kuchenbuch
- Reference Centre for Rare Epilepsies, Member of European Reference Network EpiCARE, Department of Pediatric Neurology, Hôpital Necker-Enfants Malades, Assistance Publique Hôpitaux de Paris, Paris75015, France
- Laboratory of Translational Research for Neurological Disorders, Inserm UMR 1163, Imagine Institute, Université Paris Cité, Paris75015, France
| | - Jennifer Lavigne
- University Cote d’Azur, Institute of Molecular and Cellular Pharmacology, Valbonne-Sophia Antipolis06560, France
- CNRS UMR 7275, Valbonne-Sophia Antipolis06560, France
- Inserm U1323, Valbonne-Sophia Antipolis06650, France
| | | | | | - Marco Lorenzi
- University Cote d’Azur, Institute of Molecular and Cellular Pharmacology, Valbonne-Sophia Antipolis06560, France
- Epione Research team, Inria Center of Université Côte d’Azur, Biot-Sophia Antipolis06410, France
| | - Rima Nabbout
- Reference Centre for Rare Epilepsies, Member of European Reference Network EpiCARE, Department of Pediatric Neurology, Hôpital Necker-Enfants Malades, Assistance Publique Hôpitaux de Paris, Paris75015, France
- Laboratory of Translational Research for Neurological Disorders, Inserm UMR 1163, Imagine Institute, Université Paris Cité, Paris75015, France
| | - Massimo Mantegazza
- University Cote d’Azur, Institute of Molecular and Cellular Pharmacology, Valbonne-Sophia Antipolis06560, France
- CNRS UMR 7275, Valbonne-Sophia Antipolis06560, France
- Inserm U1323, Valbonne-Sophia Antipolis06650, France
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Shaker H, Li J, Kobayashi M, Grinenko O, Bulacio J, Leahy RM, Chauvel P. Is High-Frequency Activity at Seizure Onset Inhibitory? A Stereoelectroencephalographic Study of Motor Cortex Seizures. Ann Neurol 2024; 95:1127-1137. [PMID: 38481022 DOI: 10.1002/ana.26883] [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: 02/17/2023] [Revised: 12/26/2023] [Accepted: 12/28/2023] [Indexed: 05/18/2024]
Abstract
OBJECTIVE In the era of stereoelectroencephalography (SEEG), many studies have been devoted to understanding the role of interictal high-frequency oscillations. High-frequency activity (HFA) at seizure onset has been identified as a marker of epileptogenic zone. We address the physiological significance of ictal HFAs and their relation to clinical semiology. METHODS We retrospectively identified patients with pure focal primary motor epilepsy. We selected only patients in whom SEEG electrodes were optimally placed in the motor cortex as confirmed by electrical stimulation. Based on these narrow inclusion criteria, we extensively studied 5 patients (3 males and 2 females, mean age = 22.4 years) using time-frequency analysis and time correlation with motor signs onset. RESULTS A total of 157 analyzable seizures were recorded in 5 subjects. The first 2 subjects had tonic or clonic semiology with rare secondary generalization. Subject 3 had atonic onset followed by clonic hand/arm flexion. Subject 4 had clusters of tonic and atonic facial movements. Subject 5 had upper extremity tonic movements. The median frequency of the fast activity extracted from the Epileptogenic Zone Fingerprint pipeline in the first 4 subjects was 76 Hz (interquartile range = 21.9Hz). Positive motor signs did not occur concomitantly with high gamma activity developing in the motor cortex. Motor signs began at the end of HFAs. INTERPRETATION This study supports the hypothesis of an inhibitory effect of ictal HFAs. The frequency range in the gamma band was associated with the direction of the clinical output effect. Changes from inhibitory to excitatory effect occurred when discharge frequency dropped to low gamma or beta. ANN NEUROL 2024;95:1127-1137.
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Affiliation(s)
- Hussam Shaker
- Epilepsy Center, Trinity Health Hauenstein Center, Grand Rapids, MI, USA
| | - Jian Li
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
- Center for Neurotechnology and Neurorecovery, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Masako Kobayashi
- Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Olesya Grinenko
- Epilepsy Center, Trinity Health Hauenstein Center, Grand Rapids, MI, USA
| | - Juan Bulacio
- Epilepsy Center, Cleveland Clinic Neurological Institute, Cleveland, OH, USA
| | - Richard M Leahy
- Signal and Image Processing Institute, University of Southern California, Los Angeles, CA, USA
| | - Patrick Chauvel
- Neurological Institute, Cleveland Clinic, Cleveland, OH, USA
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Ye H, Chen C, Weiss SA, Wang S. Pathological and Physiological High-frequency Oscillations on Electroencephalography in Patients with Epilepsy. Neurosci Bull 2024; 40:609-620. [PMID: 37999861 PMCID: PMC11127900 DOI: 10.1007/s12264-023-01150-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2023] [Accepted: 09/28/2023] [Indexed: 11/25/2023] Open
Abstract
High-frequency oscillations (HFOs) encompass ripples (80 Hz-200 Hz) and fast ripples (200 Hz-600 Hz), serving as a promising biomarker for localizing the epileptogenic zone in epilepsy. Spontaneous fast ripples are always pathological, while ripples may be physiological or pathological. Distinguishing physiological from pathological ripples is important not only for designating epileptogenic brain regions, but also for investigations that study ripples in the context of memory encoding, consolidation, and recall in patients with epilepsy. Many studies have sought to identify distinguishing features between pathological and physiological ripples over the past two decades. Physiological and pathological ripples differ with respect to their spatial location, cellular mechanisms, morphology, and coupling with background electroencephalographic activity. Retrospective studies have demonstrated that differentiating between pathological and physiological ripples can improve surgical outcome prediction. In this review, we summarize the characteristics, differences, and applications of pathological and physiological HFOs and discuss strategies for their clinical translation.
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Affiliation(s)
- Hongyi Ye
- Department of Neurology, Epilepsy Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310009, China
| | - Cong Chen
- Department of Neurology, Epilepsy Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310009, China
| | - Shennan A Weiss
- Department of Neurology, State University of New York Downstate, Brooklyn, NY, 11203, USA
- Department of Physiology and Pharmacology, State University of New York Downstate, Brooklyn, NY, 11203, USA
- Department of Neurology, New York City Health + Hospitals/Kings County, Brooklyn, NY, 11203, USA
| | - Shuang Wang
- Department of Neurology, Epilepsy Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310009, China.
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Li X, Qu Z, Li Z, Su R, Yin B, Yin L. Effect of GABAa-receptors on neuronal discharge and ion activity in focal seizures. Cereb Cortex 2024; 34:bhae110. [PMID: 38518225 DOI: 10.1093/cercor/bhae110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Revised: 02/24/2024] [Accepted: 02/26/2024] [Indexed: 03/24/2024] Open
Abstract
Focal seizures are a type of epileptic event that has plagued the medical community for a long time, and the existing drug treatment is mainly based on the modulation of ${GABA}_a$-receptors to affect GABAergic signaling to achieve the therapeutic purpose. The majority of research currently focuses on the impact of ${GABA}_a$-receptors on neuronal firing, failing to analyze the molecular and ionic mechanisms involved. Specifically, the research on deeper-level mechanisms on how ${GABA}_a$-receptors affect neuronal firing by altering ion activity has not been addressed. This research aimed to study the effects of different ${GABA}_a$-receptor structures on ion activity in focal seizures model by adjusting parameters of the ${GABA}_a$-receptors: the rise time constant (${tau}_1$) and decay time constant (${tau}_2$). The research indicates that as the values of ${tau}_1$ and ${tau}_2$ of the ${GABA}_a$-receptor change, the ion concentration will vary based on the change of the ${GABA}_a$-receptor potential. To a certain extent, the duration of epileptic activity will also be affected to a certain extent. In conclusion, the alteration of ${GABA}_a$-receptor structure will affect the inhibitory effect of interneurons on pyramidal neurons, and different parameters of the ${GABA}_a$-receptor will directly impact the therapeutic effect.
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Affiliation(s)
- Xin Li
- School of Electrical Engineering, Yanshan University, Qinhuangdao, Hebei 066004, P.R. China
- Measurement Technology and Instrumentation Key Lab of Hebei Province, Qinhuangdao, Hebei 066004, P.R. China
| | - Zhongjie Qu
- School of Electrical Engineering, Yanshan University, Qinhuangdao, Hebei 066004, P.R. China
- Measurement Technology and Instrumentation Key Lab of Hebei Province, Qinhuangdao, Hebei 066004, P.R. China
| | - Zipeng Li
- School of Electrical Engineering, Yanshan University, Qinhuangdao, Hebei 066004, P.R. China
- Measurement Technology and Instrumentation Key Lab of Hebei Province, Qinhuangdao, Hebei 066004, P.R. China
| | - Rui Su
- School of Medical Imaging, Hebei Medical University, Shijiazhuang, Hebei 050011, P.R. China
| | - Bowen Yin
- Department of Neurology, The First Hospital of Qinhuangdao, Qinhuangdao, Hebei 066000, P.R. China
| | - Liyong Yin
- Department of Neurology, The First Hospital of Qinhuangdao, Qinhuangdao, Hebei 066000, P.R. China
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Zhang L, Ma Z, Yu Y, Li B, Wu S, Liu Y, Baier G. Examining the low-voltage fast seizure-onset and its response to optogenetic stimulation in a biophysical network model of the hippocampus. Cogn Neurodyn 2024; 18:265-282. [PMID: 38406204 PMCID: PMC10881931 DOI: 10.1007/s11571-023-09935-1] [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: 03/30/2022] [Revised: 11/07/2022] [Accepted: 01/24/2023] [Indexed: 02/12/2023] Open
Abstract
Low-voltage fast (LVF) seizure-onset is one of the two frequently observed temporal lobe seizure-onset patterns. Depth electroencephalogram profile analysis illustrated that the peak amplitude of LVF onset was deep temporal areas, e.g., hippocampus. However, the specific dynamic transition mechanisms between normal hippocampal rhythmic activity and LVF seizure-onset remain unclear. Recently, the optogenetic approach to gain control over epileptic hyper-excitability both in vitro and in vivo has become a novel noninvasive modulation strategy. Here, we combined biophysical modeling to study LVF dynamics following changes in crucial physiological parameters, and investigated the potential optogenetic intervention mechanism for both excitatory and inhibitory control. In an Ammon's horn 3 (CA3) biophysical model with light-sensitive protein channelrhodopsin 2 (ChR2), we found that the cooperative effects of excessive extracellular potassium concentration of parvalbumin-positive (PV+) inhibitory interneurons and synaptic links could induce abundant types of discharges of the hippocampus, and lead to transitions from gamma oscillations to LVF seizure-onset. Simulations of optogenetic stimulation revealed that the LVF seizure-onset and morbid fast spiking could not be eliminated by targeting PV+ neurons, whereas the epileptic network was more sensitive to the excitatory control of principal neurons with strong optogenetic currents. We illustrate that in the epileptic hippocampal network, the trajectories of the normal and the seizure state are in close vicinity and optogenetic perturbations therefore may result in transitions. The network model system developed in this study represents a scientific instrument to disclose the underlying principles of LVF, to characterize the effects of optogenetic neuromodulation, and to guide future treatment for specific types of seizures.
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Affiliation(s)
- Liyuan Zhang
- Department of Biomedical Engineering, Faculty of Environment and Life, Beijing University of Technology, Beijing, 100124 China
| | - Zhiyuan Ma
- Department of Biomedical Engineering, Faculty of Environment and Life, Beijing University of Technology, Beijing, 100124 China
| | - Ying Yu
- School of Engineering Medicine, Beihang University, Beijing, 100191 China
| | - Bao Li
- Department of Biomedical Engineering, Faculty of Environment and Life, Beijing University of Technology, Beijing, 100124 China
| | - Shuicai Wu
- Department of Biomedical Engineering, Faculty of Environment and Life, Beijing University of Technology, Beijing, 100124 China
| | - Youjun Liu
- Department of Biomedical Engineering, Faculty of Environment and Life, Beijing University of Technology, Beijing, 100124 China
| | - Gerold Baier
- Cell and Developmental Biology, University College London, London, WC1E 6BT UK
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Ye H, Ye L, Hu L, Yang Y, Ge Y, Chen R, Wang S, Jin B, Ming W, Wang Z, Xu S, Xu C, Wang Y, Ding Y, Zhu J, Ding M, Chen Z, Wang S, Chen C. Widespread slow oscillations support interictal epileptiform discharge networks in focal epilepsy. Neurobiol Dis 2024; 191:106409. [PMID: 38218457 DOI: 10.1016/j.nbd.2024.106409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2023] [Revised: 01/01/2024] [Accepted: 01/09/2024] [Indexed: 01/15/2024] Open
Abstract
Interictal epileptiform discharges (IEDs) often co-occur across spatially-separated cortical regions, forming IED networks. However, the factors prompting IED propagation remain unelucidated. We hypothesized that slow oscillations (SOs) might facilitate IED propagation. Here, the amplitude and phase synchronization of SOs preceding propagating and non-propagating IEDs were compared in 22 patients with focal epilepsy undergoing intracranial electroencephalography (EEG) evaluation. Intracranial channels were categorized into the irritative zone (IZ) and normal zone (NOZ) regarding the presence of IEDs. During wakefulness, we found that pre-IED SOs within the IZ exhibited higher amplitudes for propagating IEDs than non-propagating IEDs (delta band: p = 0.001, theta band: p < 0.001). This increase in SOs was also concurrently observed in the NOZ (delta band: p = 0.04). Similarly, the inter-channel phase synchronization of SOs prior to propagating IEDs was higher than those preceding non-propagating IEDs in the IZ (delta band: p = 0.04). Through sliding window analysis, we observed that SOs preceding propagating IEDs progressively increased in amplitude and phase synchronization, while those preceding non-propagating IEDs remained relatively stable. Significant differences in amplitude occurred approximately 1150 ms before IEDs. During non-rapid eye movement (NREM) sleep, SOs on scalp recordings also showed higher amplitudes before intracranial propagating IEDs than before non-propagating IEDs (delta band: p = 0.006). Furthermore, the analysis of IED density around sleep SOs revealed that only high-amplitude sleep SOs demonstrated correlation with IED propagation. Overall, our study highlights that transient but widely distributed SOs are associated with IED propagation as well as generation in focal epilepsy during sleep and wakefulness, providing new insight into the EEG substrate supporting IED networks.
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Affiliation(s)
- Hongyi Ye
- Department of Neurology and Epilepsy Center, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China; Nanhu Brain-computer Interface Institute, Hangzhou, China
| | - Lingqi Ye
- Department of Neurology and Epilepsy Center, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Lingli Hu
- Department of Neurology and Epilepsy Center, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yuyu Yang
- Department of Neurology and Epilepsy Center, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yi Ge
- Department of Neurology and Epilepsy Center, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Ruotong Chen
- Department of Neurology and Epilepsy Center, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Shan Wang
- Department of Neurology and Epilepsy Center, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Bo Jin
- Department of Neurology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Wenjie Ming
- Department of Neurology and Epilepsy Center, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Zhongjin Wang
- Department of Neurology and Epilepsy Center, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Sha Xu
- Department of Neurology and Epilepsy Center, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Cenglin Xu
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
| | - Yi Wang
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
| | - Yao Ding
- Department of Neurology and Epilepsy Center, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Junming Zhu
- Department of Neurosurgery and Epilepsy Center, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Meiping Ding
- Department of Neurology and Epilepsy Center, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Zhong Chen
- Department of Neurology and Epilepsy Center, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China; Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
| | - Shuang Wang
- Department of Neurology and Epilepsy Center, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China; Nanhu Brain-computer Interface Institute, Hangzhou, China.
| | - Cong Chen
- Department of Neurology and Epilepsy Center, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.
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Agopyan-Miu AH, Merricks EM, Smith EH, McKhann GM, Sheth SA, Feldstein NA, Trevelyan AJ, Schevon CA. Cell-type specific and multiscale dynamics of human focal seizures in limbic structures. Brain 2023; 146:5209-5223. [PMID: 37536281 PMCID: PMC10689922 DOI: 10.1093/brain/awad262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Revised: 06/30/2023] [Accepted: 07/19/2023] [Indexed: 08/05/2023] Open
Abstract
The relationship between clinically accessible epileptic biomarkers and neuronal activity underlying the transition to seizure is complex, potentially leading to imprecise delineation of epileptogenic brain areas. In particular, the pattern of interneuronal firing at seizure onset remains under debate, with some studies demonstrating increased firing and others suggesting reductions. Previous study of neocortical sites suggests that seizure recruitment occurs upon failure of inhibition, with intact feedforward inhibition in non-recruited territories. We investigated whether the same principle applies in limbic structures. We analysed simultaneous electrocorticography (ECoG) and neuronal recordings of 34 seizures in a cohort of 19 patients (10 male, 9 female) undergoing surgical evaluation for pharmacoresistant focal epilepsy. A clustering approach with five quantitative metrics computed from ECoG and multiunit data was used to distinguish three types of site-specific activity patterns during seizures, which at times co-existed within seizures. Overall, 156 single units were isolated, subclassified by cell-type and tracked through the seizure using our previously published methods to account for impacts of increased noise and single-unit waveshape changes caused by seizures. One cluster was closely associated with clinically defined seizure onset or spread. Entrainment of high-gamma activity to low-frequency ictal rhythms was the only metric that reliably identified this cluster at the level of individual seizures (P < 0.001). A second cluster demonstrated multi-unit characteristics resembling those in the first cluster, without concomitant high-gamma entrainment, suggesting feedforward effects from the seizure. The last cluster captured regions apparently unaffected by the ongoing seizure. Across all territories, the majority of both excitatory and inhibitory neurons reduced (69.2%) or ceased firing (21.8%). Transient increases in interneuronal firing rates were rare (13.5%) but showed evidence of intact feedforward inhibition, with maximal firing rate increases and waveshape deformations in territories not fully recruited but showing feedforward activity from the seizure, and a shift to burst-firing in seizure-recruited territories (P = 0.014). This study provides evidence for entrained high-gamma activity as an accurate biomarker of ictal recruitment in limbic structures. However, reduced neuronal firing suggested preserved inhibition in mesial temporal structures despite simultaneous indicators of seizure recruitment, in contrast to the inhibitory collapse scenario documented in neocortex. Further study is needed to determine if this activity is ubiquitous to hippocampal seizures or indicates a 'seizure-responsive' state in which the hippocampus is not the primary driver. If the latter, distinguishing such cases may help to refine the surgical treatment of mesial temporal lobe epilepsy.
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Affiliation(s)
- Alexander H Agopyan-Miu
- Department of Neurological Surgery, Columbia University Medical Center, NewYork, NY 10032, USA
| | - Edward M Merricks
- Department of Neurology, Columbia University Medical Center, NewYork, NY 10032, USA
| | - Elliot H Smith
- Department of Neurology, Columbia University Medical Center, NewYork, NY 10032, USA
- Department of Neurosurgery, University of Utah, Salt Lake City, UT 84132, USA
| | - Guy M McKhann
- Department of Neurological Surgery, Columbia University Medical Center, NewYork, NY 10032, USA
| | - Sameer A Sheth
- Department of Neurosurgery, Baylor College of Medicine, Houston TX 77030, USA
| | - Neil A Feldstein
- Department of Neurological Surgery, Columbia University Medical Center, NewYork, NY 10032, USA
| | - Andrew J Trevelyan
- Biosciences Institute, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Catherine A Schevon
- Department of Neurology, Columbia University Medical Center, NewYork, NY 10032, USA
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Wenzel M, Huberfeld G, Grayden DB, de Curtis M, Trevelyan AJ. A debate on the neuronal origin of focal seizures. Epilepsia 2023; 64 Suppl 3:S37-S48. [PMID: 37183507 DOI: 10.1111/epi.17650] [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: 02/09/2023] [Revised: 04/26/2023] [Accepted: 05/12/2023] [Indexed: 05/16/2023]
Abstract
A critical question regarding how focal seizures start is whether we can identify particular cell classes that drive the pathological process. This was the topic for debate at the recent International Conference for Technology and Analysis of Seizures (ICTALS) meeting (July 2022, Bern, CH) that we summarize here. The debate has been fueled in recent times by the introduction of powerful new ways to manipulate subpopulations of cells in relative isolation, mostly using optogenetics. The motivation for resolving the debate is to identify novel targets for therapeutic interventions through a deeper understanding of the etiology of seizures.
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Affiliation(s)
- Michael Wenzel
- Department of Epileptology, University Hospital Bonn, University of Bonn, Bonn, Germany
| | - Gilles Huberfeld
- Neurology Department, Hopital Fondation Adolphe de Rothschild, Paris, France
- Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS, INSERM, Université PSL, Paris, France
| | - David B Grayden
- Department of Biomedical Engineering, The University of Melbourne, Melbourne, Victoria, Australia
- Department of Medicine, St Vincent's Hospital, The University of Melbourne, Melbourne, Victoria, Australia
- Graeme Clark Institute, The University of Melbourne, Melbourne, Victoria, Australia
| | - Marco de Curtis
- Epilepsy Unit, Fondazione I.R.C.C.S., Istituto Neurologico Carlo Besta, Milan, Italy
| | - Andrew J Trevelyan
- Newcastle University Biosciences Institute, Medical School, Framlington Place, Newcastle upon Tyne, UK
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10
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Guo F, Cui Y, Li A, Liu M, Jian Z, Chen K, Yao D, Guo D, Xia Y. Differential patterns of very high-frequency oscillations in two seizure types of the pilocarpine-induced TLE model. Brain Res Bull 2023; 204:110805. [PMID: 37925081 DOI: 10.1016/j.brainresbull.2023.110805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Revised: 10/08/2023] [Accepted: 10/30/2023] [Indexed: 11/06/2023]
Abstract
AIMS Very high-frequency oscillations (VHFOs, >500 Hz) are considered a highly sensitive biomarker of seizures. We hypothesized that VHFOs may exhibit specificity towards hypersynchronous (HYP) seizures and low-voltage fast (LVF) seizures in temporal lobe epilepsy (TLE). METHODS Local field potentials were recorded from the hippocampal network in TLE mice induced by pilocarpine. Subsequently, we analyzed the VHFO features, including their temporal-frequency characteristics and VHFO/theta coupling, during three states: baseline, preictal, and postictal for both HYP- and LVF-seizure groups. RESULTS Significant changes in most of the VHFO features were observed during the preictal state in both seizure groups. In the postictal state, VHFO features in the HYP-seizure group exhibited inverse alterations and appeared to align with those observed during baseline conditions. However, such phenomena were not observed after TLE seizures in the LVF-seizure group. CONCLUSION Our findings highlight distinct patterns of VHFO feature changes across different states of HYP seizures and LVF seizures. These results suggest that VHFOs could serve as indicative biomarkers for seizure alterations specifically associated with HYP-seizure states.
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Affiliation(s)
- Fengru Guo
- Department of Neurosurgery, Sichuan Provincial People's Hospital, MOE Key Lab for Neuroinformation, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Yan Cui
- Department of Neurosurgery, Sichuan Provincial People's Hospital, MOE Key Lab for Neuroinformation, University of Electronic Science and Technology of China, Chengdu 611731, China.
| | - Airui Li
- Department of Neurosurgery, Sichuan Provincial People's Hospital, MOE Key Lab for Neuroinformation, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Mingqi Liu
- Department of Neurosurgery, Sichuan Provincial People's Hospital, MOE Key Lab for Neuroinformation, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Zhaoxin Jian
- Department of Neurosurgery, Sichuan Provincial People's Hospital, MOE Key Lab for Neuroinformation, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Ke Chen
- Department of Neurosurgery, Sichuan Provincial People's Hospital, MOE Key Lab for Neuroinformation, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Dezhong Yao
- Department of Neurosurgery, Sichuan Provincial People's Hospital, MOE Key Lab for Neuroinformation, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Daqing Guo
- Department of Neurosurgery, Sichuan Provincial People's Hospital, MOE Key Lab for Neuroinformation, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Yang Xia
- Department of Neurosurgery, Sichuan Provincial People's Hospital, MOE Key Lab for Neuroinformation, University of Electronic Science and Technology of China, Chengdu 611731, China.
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11
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Jean G, Carton J, Haq K, Musto AE. The role of dendritic spines in epileptogenesis. Front Cell Neurosci 2023; 17:1173694. [PMID: 37601280 PMCID: PMC10433379 DOI: 10.3389/fncel.2023.1173694] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 07/06/2023] [Indexed: 08/22/2023] Open
Abstract
Epilepsy is a chronic central nervous system (CNS) disease associated with high morbidity. To date, there is no known disease-modifying therapy for epilepsy. A leading hypothesis for a mechanism of epileptogenesis is the generation of aberrant neuronal networks. Although the underlying biological mechanism is not clear, scientific evidence indicates that it is associated with a hyperexcitable synchronous neuronal network and active dendritic spine plasticity. Changes in dendritic spine morphology are related to altered expression of synaptic cytoskeletal proteins, inflammatory molecules, neurotrophic factors, and extracellular matrix signaling. However, it remains to be determined if these aberrant dendritic spine formations lead to neuronal hyperexcitability and abnormal synaptic connections or whether they constitute an underlying mechanism of seizure susceptibility. Focusing on dendritic spine machinery as a potential target for medications could limit or reverse the development of epilepsy.
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Affiliation(s)
- Gary Jean
- Medical Program, School of Medicine, Eastern Virginia Medical School, Norfolk, VA, United States
| | - Joseph Carton
- Medical Program, School of Medicine, Eastern Virginia Medical School, Norfolk, VA, United States
| | - Kaleem Haq
- Department of Pathology and Anatomy, Eastern Virginia Medical School, Norfolk, VA, United States
| | - Alberto E. Musto
- Department of Pathology and Anatomy, Eastern Virginia Medical School, Norfolk, VA, United States
- Department of Neurology, Eastern Virginia Medical School, Norfolk, VA, United States
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12
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Magloire V, Savtchenko LP, Jensen TP, Sylantyev S, Kopach O, Cole N, Tyurikova O, Kullmann DM, Walker MC, Marvin JS, Looger LL, Hasseman JP, Kolb I, Pavlov I, Rusakov DA. Volume-transmitted GABA waves pace epileptiform rhythms in the hippocampal network. Curr Biol 2023; 33:1249-1264.e7. [PMID: 36921605 PMCID: PMC10615848 DOI: 10.1016/j.cub.2023.02.051] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 01/05/2023] [Accepted: 02/15/2023] [Indexed: 03/17/2023]
Abstract
Mechanisms that entrain and pace rhythmic epileptiform discharges remain debated. Traditionally, the quest to understand them has focused on interneuronal networks driven by synaptic GABAergic connections. However, synchronized interneuronal discharges could also trigger the transient elevations of extracellular GABA across the tissue volume, thus raising tonic conductance (Gtonic) of synaptic and extrasynaptic GABA receptors in multiple cells. Here, we monitor extracellular GABA in hippocampal slices using patch-clamp GABA "sniffer" and a novel optical GABA sensor, showing that periodic epileptiform discharges are preceded by transient, region-wide waves of extracellular GABA. Neural network simulations that incorporate volume-transmitted GABA signals point to a cycle of GABA-driven network inhibition and disinhibition underpinning this relationship. We test and validate this hypothesis using simultaneous patch-clamp recordings from multiple neurons and selective optogenetic stimulation of fast-spiking interneurons. Critically, reducing GABA uptake in order to decelerate extracellular GABA fluctuations-without affecting synaptic GABAergic transmission or resting GABA levels-slows down rhythmic activity. Our findings thus unveil a key role of extrasynaptic, volume-transmitted GABA in pacing regenerative rhythmic activity in brain networks.
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Affiliation(s)
- Vincent Magloire
- UCL Queen Square Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK.
| | - Leonid P Savtchenko
- UCL Queen Square Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK.
| | - Thomas P Jensen
- UCL Queen Square Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK
| | - Sergyi Sylantyev
- UCL Queen Square Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK; Rowett Institute, University of Aberdeen, Ashgrove Road West, Aberdeen AB25 2ZD, UK
| | - Olga Kopach
- UCL Queen Square Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK
| | - Nicholas Cole
- UCL Queen Square Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK
| | - Olga Tyurikova
- UCL Queen Square Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK
| | - Dimitri M Kullmann
- UCL Queen Square Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK
| | - Matthew C Walker
- UCL Queen Square Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK
| | - Jonathan S Marvin
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Loren L Looger
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA; Howard Hughes Medical Institute, University of California, San Diego, La Jolla, CA 92093, USA; GENIE Project Team, Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Jeremy P Hasseman
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA; GENIE Project Team, Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Ilya Kolb
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA; GENIE Project Team, Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Ivan Pavlov
- UCL Queen Square Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK
| | - Dmitri A Rusakov
- UCL Queen Square Institute of Neurology, University College London, Queen Square, London WC1N 3BG, UK.
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13
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Avoli M, Chen LY, Di Cristo G, Librizzi L, Scalmani P, Shiri Z, Uva L, de Curtis M, Lévesque M. Ligand-gated mechanisms leading to ictogenesis in focal epileptic disorders. Neurobiol Dis 2023; 180:106097. [PMID: 36967064 DOI: 10.1016/j.nbd.2023.106097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 03/14/2023] [Accepted: 03/22/2023] [Indexed: 04/03/2023] Open
Abstract
We review here the neuronal mechanisms that cause seizures in focal epileptic disorders and, specifically, those involving limbic structures that are known to be implicated in human mesial temporal lobe epilepsy. In both epileptic patients and animal models, the initiation of focal seizures - which are most often characterized by a low-voltage fast onset EEG pattern - is presumably dependent on the synchronous firing of GABA-releasing interneurons that, by activating post-synaptic GABAA receptors, cause large increases in extracellular [K+] through the activation of the co-transporter KCC2. A similar mechanism may contribute to seizure maintenance; accordingly, inhibiting KCC2 activity transforms seizure activity into a continuous pattern of short-lasting epileptiform discharges. It has also been found that interactions between different areas of the limbic system modulate seizure occurrence by controlling extracellular [K+] homeostasis. In line with this view, low-frequency electrical or optogenetic activation of limbic networks restrain seizure generation, an effect that may also involve the activation of GABAB receptors and activity-dependent changes in epileptiform synchronization. Overall, these findings highlight the paradoxical role of GABAA signaling in both focal seizure generation and maintenance, emphasize the efficacy of low-frequency activation in abating seizures, and provide experimental evidence explaining the poor efficacy of antiepileptic drugs designed to augment GABAergic function in controlling seizures in focal epileptic disorders.
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Affiliation(s)
- Massimo Avoli
- Montreal Neurological Institute-Hospital, Departments of Neurology, Canada; Neurology & Neurosurgery and of Physiology, McGill University, Montreal H3A 2B4, Que, Canada.
| | - Li-Yuan Chen
- Montreal Neurological Institute-Hospital, Departments of Neurology, Canada
| | - Graziella Di Cristo
- Neurosciences Department, Université de Montréal, Montréal, Québec H3T 1N8, Canada; CHU Sainte-Justine Research Center, Montréal, Québec H3T 1C5, Canada
| | - Laura Librizzi
- Epilepsy Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy
| | - Paolo Scalmani
- Epilepsy Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy
| | - Zahra Shiri
- Montreal Neurological Institute-Hospital, Departments of Neurology, Canada
| | - Laura Uva
- Epilepsy Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy
| | - Marco de Curtis
- Epilepsy Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy
| | - Maxime Lévesque
- Montreal Neurological Institute-Hospital, Departments of Neurology, Canada
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14
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Scalmani P, Paterra R, Mantegazza M, Avoli M, de Curtis M. Involvement of GABAergic Interneuron Subtypes in 4-Aminopyridine-Induced Seizure-Like Events in Mouse Entorhinal Cortex in Vitro. J Neurosci 2023; 43:1987-2001. [PMID: 36810229 PMCID: PMC10027059 DOI: 10.1523/jneurosci.1190-22.2023] [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: 06/17/2022] [Revised: 12/30/2022] [Accepted: 01/05/2023] [Indexed: 02/23/2023] Open
Abstract
Single-unit recordings performed in temporal lobe epilepsy patients and in models of temporal lobe seizures have shown that interneurons are active at focal seizure onset. We performed simultaneous patch-clamp and field potential recordings in entorhinal cortex slices of GAD65 and GAD67 C57BL/6J male mice that express green fluorescent protein in GABAergic neurons to analyze the activity of specific interneuron (IN) subpopulations during acute seizure-like events (SLEs) induced by 4-aminopyridine (4-AP; 100 μm). IN subtypes were identified as parvalbuminergic (INPV, n = 17), cholecystokinergic (INCCK), n = 13], and somatostatinergic (INSOM, n = 15), according to neurophysiological features and single-cell digital PCR. INPV and INCCK discharged at the start of 4-AP-induced SLEs characterized by either low-voltage fast or hyper-synchronous onset pattern. In both SLE onset types, INSOM fired earliest before SLEs, followed by INPV and INCCK discharges. Pyramidal neurons became active with variable delays after SLE onset. Depolarizing block was observed in ∼50% of cells in each INs subgroup, and it was longer in IN (∼4 s) than in pyramidal neurons (<1 s). As SLE evolved, all IN subtypes generated action potential bursts synchronous with the field potential events leading to SLE termination. High-frequency firing throughout the SLE occurred in one-third of INPV and INSOM We conclude that entorhinal cortex INs are very active at the onset and during the progression of SLEs induced by 4-AP. These results support earlier in vivo and in vivo evidence and suggest that INs have a preferential role in focal seizure initiation and development.SIGNIFICANCE STATEMENT Focal seizures are believed to result from enhanced excitation. Nevertheless, we and others demonstrated that cortical GABAergic networks may initiate focal seizures. Here, we analyzed for the first time the role of different IN subtypes in seizures generated by 4-aminopyridine in the mouse entorhinal cortex slices. We found that in this in vitro focal seizure model, all IN types contribute to seizure initiation and that INs precede firing of principal cells. This evidence is in agreement with the active role of GABAergic networks in seizure generation.
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Affiliation(s)
| | - Rosina Paterra
- Neuro-Oncology Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano 20133, Italy
| | - Massimo Mantegazza
- Université Côte d'Azur, 06560 Valbonne-Sophia Antipolis, France
- Institute of Molecular and Cellular Pharmacology, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7275, Laboratoire d'Excellence/Canaux Ioniques d'Intérêt Thérapeutique, 06650 Valbonne-Sophia Antipolis, France
- Institut National de la Santé et de la Recherche Médicale, 06650 Valbonne-Sophia Antipolis, France
| | - Massimo Avoli
- Montreal Neurological Institute-Hospital, McGill University, Montreal, Quebec H3A 2B4, Canada
- Departments of Neurology and Neurosurgery and Physiology, McGill University, Montreal, Quebec H3A 2B4, Canada
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15
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Trevelyan AJ, Graham RT, Parrish RR, Codadu NK. Synergistic Positive Feedback Mechanisms Underlying Seizure Initiation. Epilepsy Curr 2023; 23:38-43. [PMID: 36923333 PMCID: PMC10009126 DOI: 10.1177/15357597221127163] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Investigations into seizure initiation, in recent years, have focused almost entirely upon alterations of interneuronal function, chloride homeostasis, and extracellular potassium levels. In contrast, little attention has been directed toward a possible role of dendritic plateau potentials in the actual ictogenic transition, despite a substantial literature dating back 40 years regarding its importance generally in epilepsy. Here, we argue that an increase in dendritic excitability, coordinated across the population of pyramidal cells, is a key stage in ictogenesis.
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Affiliation(s)
- Andrew J. Trevelyan
- Newcastle University Biosciences Institute, Medical School, Framlington Place, Newcastle upon Tyne, United Kingdom
| | - Robert T. Graham
- Queen Square Institute of Neurology, University College London, United Kingdom
| | - R. Ryley Parrish
- Department of Cell Biology and Physiology, Brigham Young University, Provo, UT, USA
| | - Neela K. Codadu
- Queen Square Institute of Neurology, University College London, United Kingdom
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16
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Hu L, Xiong K, Ye L, Yang Y, Chen C, Wang S, Ding Y, Wang Z, Ming W, Zheng Z, Jiang H, Li H, Zhu J, Xu C, Wang Y, Ding M, Chen Z, Wu Y, Wang S. Ictal EEG desynchronization during low-voltage fast activity for prediction of surgical outcomes in focal epilepsy. J Neurosurg 2022:1-10. [PMID: 36681967 DOI: 10.3171/2022.11.jns221469] [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: 06/22/2022] [Accepted: 11/15/2022] [Indexed: 12/24/2022]
Abstract
OBJECTIVE The authors investigated alterations in functional connectivity (FC) and EEG power during ictal onset patterns of low-voltage fast activity (LVFA) in drug-resistant focal epilepsy. They hypothesized that such changes would be useful to classify epilepsy surgical outcomes. METHODS In a cohort of 79 patients with drug-resistant focal epilepsy who underwent stereoelectroencephalography (SEEG) evaluation as well as resective surgery, FC changes during the peri-LVFA period were measured using nonlinear regression (h2) and power spectral properties within/between three regions: the seizure onset zone (SOZ), early propagation zone (PZ), and noninvolved zone (NIZ). Desynchronization and power desynchronization h2 indices were calculated to assess the degree of EEG desynchronization during LVFA. Multivariate logistic regression was employed to control for confounding factors. Finally, receiver operating characteristic curves were generated to evaluate the performance of desynchronization indices in predicting surgical outcome. RESULTS Fifty-three patients showed ictal LVFA and distinct zones of the SOZ, PZ, and NIZ. Among them, 39 patients (73.6%) achieved seizure freedom by the final follow-up. EEG desynchronization, measured by h2 analysis, was found in the seizure-free group during LVFA: FC decreased within the SOZ and between regions compared with the pre-LVFA and post-LVFA periods. In contrast, the non-seizure-free group showed no prominent EEG desynchronization. The h2 desynchronization index, but not the power desynchronization index, enabled classification of seizure-free versus non-seizure-free patients after resective surgery. CONCLUSIONS EEG desynchronization during the peri-LVFA period, measured by within-zone and between-zone h2 analysis, may be helpful for identifying patients with favorable postsurgical outcomes and also may potentially improve epileptogenic zone identification in the future.
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Affiliation(s)
- Lingli Hu
- 1Department of Neurology, Epilepsy Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou
| | - Kai Xiong
- 2School of Computer Science and Technology, Zhejiang University, Hangzhou
| | - Lingqi Ye
- 1Department of Neurology, Epilepsy Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou
| | - Yuyu Yang
- 1Department of Neurology, Epilepsy Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou
| | - Cong Chen
- 1Department of Neurology, Epilepsy Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou
| | - Shan Wang
- 1Department of Neurology, Epilepsy Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou
| | - Yao Ding
- 1Department of Neurology, Epilepsy Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou
| | - Zhongjin Wang
- 1Department of Neurology, Epilepsy Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou
| | - Wenjie Ming
- 1Department of Neurology, Epilepsy Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou
| | - Zhe Zheng
- 1Department of Neurology, Epilepsy Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou
| | - Hongjie Jiang
- 1Department of Neurology, Epilepsy Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou
| | - Hong Li
- 3Department of Radiology, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou; and
| | - Junming Zhu
- 1Department of Neurology, Epilepsy Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou
| | - Cenglin Xu
- 4Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
| | - Yi Wang
- 4Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
| | - Meiping Ding
- 1Department of Neurology, Epilepsy Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou
| | - Zhong Chen
- 4Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
| | - Yingcai Wu
- 2School of Computer Science and Technology, Zhejiang University, Hangzhou
| | - Shuang Wang
- 1Department of Neurology, Epilepsy Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou
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17
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Avoli M, de Curtis M, Lévesque M, Librizzi L, Uva L, Wang S. GABAA signaling, focal epileptiform synchronization and epileptogenesis. Front Neural Circuits 2022; 16:984802. [PMID: 36275847 PMCID: PMC9581276 DOI: 10.3389/fncir.2022.984802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Accepted: 09/13/2022] [Indexed: 12/04/2022] Open
Abstract
Under physiological conditions, neuronal network synchronization leads to different oscillatory EEG patterns that are associated with specific behavioral and cognitive functions. Excessive synchronization can, however, lead to focal or generalized epileptiform activities. It is indeed well established that in both epileptic patients and animal models, focal epileptiform EEG patterns are characterized by interictal and ictal (seizure) discharges. Over the last three decades, employing in vitro and in vivo recording techniques, several experimental studies have firmly identified a paradoxical role of GABAA signaling in generating interictal discharges, and in initiating—and perhaps sustaining—focal seizures. Here, we will review these experiments and we will extend our appraisal to evidence suggesting that GABAA signaling may also contribute to epileptogenesis, i.e., the development of plastic changes in brain excitability that leads to the chronic epileptic condition. Overall, we anticipate that this information should provide the rationale for developing new specific pharmacological treatments for patients presenting with focal epileptic disorders such as mesial temporal lobe epilepsy (MTLE).
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Affiliation(s)
- Massimo Avoli
- Montreal Neurological Institute-Hospital, Montreal, QC, Canada
- Departments of Neurology and Neurosurgery, Montreal, QC, Canada
- Department of Physiology, McGill University, Montreal, QC, Canada
- *Correspondence: Massimo Avoli,
| | - Marco de Curtis
- Epilepsy Unit, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Istituto Neurologico Carlo Besta, Milan, Italy
| | - Maxime Lévesque
- Montreal Neurological Institute-Hospital, Montreal, QC, Canada
- Departments of Neurology and Neurosurgery, Montreal, QC, Canada
| | - Laura Librizzi
- Epilepsy Unit, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Istituto Neurologico Carlo Besta, Milan, Italy
| | - Laura Uva
- Epilepsy Unit, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Istituto Neurologico Carlo Besta, Milan, Italy
| | - Siyan Wang
- Montreal Neurological Institute-Hospital, Montreal, QC, Canada
- Departments of Neurology and Neurosurgery, Montreal, QC, Canada
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18
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Automatic Detection and Classification of Epileptic Seizures in Patients with Liver Cirrhosis and Overlapping Hev Infection Based on Deep Multimodal Fusion Technology. CONTRAST MEDIA & MOLECULAR IMAGING 2022; 2022:3176134. [PMID: 36105452 PMCID: PMC9452993 DOI: 10.1155/2022/3176134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 07/27/2022] [Accepted: 08/06/2022] [Indexed: 11/17/2022]
Abstract
Liver cirrhosis is a clinical chronic developmental liver disease, which is caused by long-term or repeated effects of liver dysfunction, and there are more and more cases of epileptic seizures in patients with liver cirrhosis and HEV infection. This article aims to study how to analyze epileptic seizures in patients with liver cirrhosis and overlapping HEV infection based on deep multimodal fusion technology. This article proposes a deep learning neural network algorithm based on deep multimodal fusion technology, and how to use this algorithm to automatically detect and classify epileptic seizures. The data in the experiment in this article show that the prevalence of epilepsy accounts for 1% of the world's population, about 56.7 million people, and 1 in 25 people may have an epileptic seizure at some time in their lives, and in each person's life, the probability of seizures due to various reasons is 10%. In 2016, the proportion of males with cirrhosis reached 16%, females reached 8%, and males were 8% higher than females, which is a full double. The test results show that with the increase in patients with cirrhosis and overlapping HEV infection, the frequency of epileptic seizures is also getting higher and higher, indicating that the frequency of epileptic seizures has been increased in patients with cirrhosis and overlapping HEV infection. Therefore, it is imperative to analyze the epileptic seizures of patients with liver cirrhosis and overlapping HEV infection based on deep multimodal fusion technology.
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19
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Wang S, Kfoury C, Marion A, Lévesque M, Avoli M. Modulation of in vitro epileptiform activity by optogenetic stimulation of parvalbumin-positive interneurons. J Neurophysiol 2022; 128:837-846. [PMID: 36043700 DOI: 10.1152/jn.00192.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
GABAA signaling is surprisingly involved in the initiation of epileptiform activity since increased interneuron firing, presumably leading to excessive GABA release, often precedes ictal discharges. Field potential theta (4-12 Hz) oscillations, which are thought to mirror the synchronization of interneuron networks, also lead to ictogenesis. However, the exact role of parvalbumin-positive (PV) interneurons in generating theta oscillations linked to epileptiform discharges remains unexplored. We analyzed here the field responses recorded in the CA3, entorhinal cortex (EC) and dentate gyrus (DG) during 8 Hz optogenetic stimulation of PV-positive interneurons in brain slices obtained from PV-ChR2 mice during 4-aminopyridine (4AP) application. This optogenetic protocol triggered similar field oscillations in both control conditions and during 4AP application. However, in the presence of 4AP, optogenetic stimuli also induced: (i) interictal discharges that were associated in all regions with 8 Hz field oscillations; and (ii) low-voltage fast onset ictal discharges. Interictal and ictal events occurred more frequently during optogenetic activation than during periods of no stimulation. 4AP also increased synchronicity during PV-interneuron activation in all three regions. In opsin-negative mice, optogenetic stimulation did not change the rate of both types of epileptiform activity. Our findings suggest that PV-interneuron recruitment at theta (8 Hz) frequency contributes to epileptiform synchronization in limbic structures in the in vitro 4AP model.
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Affiliation(s)
- Siyan Wang
- Montreal Neurological Institute and Hospital and Departments of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
| | - Cristen Kfoury
- Montreal Neurological Institute and Hospital and Departments of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada.,Department of Physiology, McGill University, Montreal, QC, Canada
| | - Alexis Marion
- Montreal Neurological Institute and Hospital and Departments of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada.,Department of Physiology, McGill University, Montreal, QC, Canada
| | - Maxime Lévesque
- Montreal Neurological Institute and Hospital and Departments of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
| | - Massimo Avoli
- Montreal Neurological Institute and Hospital and Departments of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada.,Department of Physiology, McGill University, Montreal, QC, Canada
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20
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Gentiletti D, de Curtis M, Gnatkovsky V, Suffczynski P. Focal seizures are organized by feedback between neural activity and ion concentration changes. eLife 2022; 11:68541. [PMID: 35916367 PMCID: PMC9377802 DOI: 10.7554/elife.68541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Accepted: 07/12/2022] [Indexed: 11/13/2022] Open
Abstract
Human and animal EEG data demonstrate that focal seizures start with low-voltage fast activity, evolve into rhythmic burst discharges and are followed by a period of suppressed background activity. This suggests that processes with dynamics in the range of tens of seconds govern focal seizure evolution. We investigate the processes associated with seizure dynamics by complementing the Hodgkin-Huxley mathematical model with the physical laws that dictate ion movement and maintain ionic gradients. Our biophysically realistic computational model closely replicates the electrographic pattern of a typical human focal seizure characterized by low voltage fast activity onset, tonic phase, clonic phase and postictal suppression. Our study demonstrates, for the first time in silico, the potential mechanism of seizure initiation by inhibitory interneurons via the initial build-up of extracellular K+ due to intense interneuronal spiking. The model also identifies ionic mechanisms that may underlie a key feature in seizure dynamics, i.e., progressive slowing down of ictal discharges towards the end of seizure. Our model prediction of specific scaling of inter-burst intervals is confirmed by seizure data recorded in the whole guinea pig brain in vitro and in humans, suggesting that the observed termination pattern may hold across different species. Our results emphasize ionic dynamics as elementary processes behind seizure generation and indicate targets for new therapeutic strategies.
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21
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Lévesque M, Wang S, Etter G, Williams S, Avoli M. Bilateral optogenetic activation of inhibitory cells favors ictogenesis. Neurobiol Dis 2022; 171:105794. [PMID: 35718264 DOI: 10.1016/j.nbd.2022.105794] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 06/10/2022] [Accepted: 06/12/2022] [Indexed: 11/26/2022] Open
Abstract
Mesial temporal lobe epilepsy (MTLE) is the most common type of focal refractory epilepsy and is characterized by recurring seizures that are often refractory to medication. Since parvalbumin-positive (PV) interneurons were recently shown to play significant roles in ictogenesis, we established here how bilateral optogenetic stimulation of these interneurons in the hippocampus CA3 regions modulates seizures, interictal spikes and high-frequency oscillations (HFOs; ripples: 80-200 Hz, fast ripples: 250-500 Hz) in the pilocarpine model of MTLE. Bilateral optogenetic stimulation of CA3 PV-positive interneurons at 8 Hz (lasting 30 s, every 2 min) was implemented in PV-ChR2 mice for 8 consecutive days starting on day 7 (n = 8) or on day 13 (n = 6) after pilocarpine-induced status epilepticus (SE). Seizure occurrence was higher in both day 7 and day 13 groups of PV-ChR2 mice during periods of optogenetic stimulation ("ON"), compared to when stimulation was not performed ("OFF") (day 7 group = p < 0.01, day 13 group = p < 0.01). In the PV-ChR2 day 13 group, rates of seizures (p < 0.05), of interictal spikes associated with fast ripples (p < 0.01), and of isolated fast ripples (p < 0.01) during optogenetic stimulations were significantly higher than in the PV-ChR2 day 7 group. Our findings reveal that bilateral activation of PV-interneurons in the hippocampus (leading to a presumptive increase in GABA signaling) favors ictogenesis. These effects may also mirror the neuropathological changes that occur over time after SE in this animal model.
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Affiliation(s)
- Maxime Lévesque
- Montreal Neurological Institute-Hospital and Departments of Neurology & Neurosurgery, and of Physiology, McGill University, 3801 University Street, Montréal, H3A 2B4, QC, Canada
| | - Siyan Wang
- Montreal Neurological Institute-Hospital and Departments of Neurology & Neurosurgery, and of Physiology, McGill University, 3801 University Street, Montréal, H3A 2B4, QC, Canada
| | - Guillaume Etter
- Douglas Mental Health University Institute, McGill University, 6875 Blvd Lasalle, Montréal, H4H 1R3, QC, Canada
| | - Sylvain Williams
- Douglas Mental Health University Institute, McGill University, 6875 Blvd Lasalle, Montréal, H4H 1R3, QC, Canada
| | - Massimo Avoli
- Montreal Neurological Institute-Hospital and Departments of Neurology & Neurosurgery, and of Physiology, McGill University, 3801 University Street, Montréal, H3A 2B4, QC, Canada.
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22
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Lado WE, Xu X, Hablitz JJ. Modulation of Epileptiform Activity by Three Subgroups of GABAergic Interneurons in Mouse Somatosensory Cortex. Epilepsy Res 2022; 183:106937. [DOI: 10.1016/j.eplepsyres.2022.106937] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 04/05/2022] [Accepted: 04/24/2022] [Indexed: 11/29/2022]
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23
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Ricci E, Fetta A, Garavelli L, Caraffi S, Ivanovski I, Bonanni P, Accorsi P, Giordano L, Pantaleoni C, Romeo A, Arena A, Bonetti S, Boni A, Chiarello D, Di Pisa V, Epifanio R, Faravelli F, Finardi E, Fiumara A, Grioni D, Mammi I, Negrin S, Osanni E, Raviglione F, Rivieri F, Rizzi R, Savasta S, Tarani L, Zanotta N, Dormi A, Vignoli A, Canevini M, Cordelli DM. Further delineation and long-term evolution of electroclinical phenotype in Mowat Wilson Syndrome. A longitudinal study in 40 individuals. Epilepsy Behav 2021; 124:108315. [PMID: 34619538 DOI: 10.1016/j.yebeh.2021.108315] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/25/2021] [Accepted: 08/29/2021] [Indexed: 11/17/2022]
Abstract
BACKGROUND Epilepsy is a main feature of Mowat Wilson Syndrome (MWS), a congenital malformation syndrome caused by ZEB2 variants. The aim of this study was to investigate the long-term evolution of the electroclinical phenotype of MWS in a large population. METHODS Forty-individuals with a genetically confirmed diagnosis were enrolled. Three age groups were identified (t1 = 0-4; t2 = 5-12; t3 = >13 years); clinical data and EEG records were collected, analyzed, and compared for age group. Video-EEG recorded seizures were reviewed. RESULTS Thirty-six of 40 individuals had epilepsy, of whom 35/35 aged >5 years. Almost all (35/36) presented focal seizures at onset (mean age at onset 3.4 ± 2.3 SD) that persisted, reduced in frequency, in 7/22 individuals after the age of 13. Absences occurred in 22/36 (mean age at onset 7.2 ± 0.9 SD); no one had absences before 6 and over 16 years old. Paroxysmal interictal abnormalities in sleep also followed an age-dependent evolution with a significant increase in frequency at school age (p = 0.002) and a reduction during adolescence (p = 0.008). Electrical Status Epilepticus during Sleep occurred in 14/36 (13/14 aged 5-13 years old at onset). Seven focal seizure ictal video-EEGs were collected: all were long-lasting and more visible clinical signs were often preceded by prolonged electrical and/or subtle (erratic head and eye orientation) seizures. Valproic acid was confirmed as the most widely used and effective drug, followed by levetiracetam. CONCLUSIONS Epilepsy is a major sign of MWS with a characteristic, age-dependent, electroclinical pattern. Improvement with adolescence/adulthood is usually observed. Our data strengthen the hypothesis of a GABAergic transmission imbalance underlying ZEB2-related epilepsy.
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Affiliation(s)
- Emilia Ricci
- Child Neuropsychiatry Unit, Epilepsy Center, San Paolo Hospital, Department of Health Sciences, University of Milan, Milan, Italy
| | - Anna Fetta
- IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Neuropsichiatria dell'Età Pediatrica, Bologna, Italy; Department of Medical and Surgical Sciences (DIMEC), Sant'Orsola Hospital, University of Bologna, Bologna, Italy.
| | - Livia Garavelli
- Medical Genetics Unit, Department of Mother and Child, AUSL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
| | - Stefano Caraffi
- Medical Genetics Unit, Department of Mother and Child, AUSL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
| | - Ivan Ivanovski
- Insitut für Medizinische Genetik, Universität Zürich, Zürich, Switzerland
| | - Paolo Bonanni
- Epilepsy and Clinical Neurophysiology Unit, Scientific Institute, IRCCS Eugenio Medea, Conegliano, Treviso, Italy
| | - Patrizia Accorsi
- Child Neurology and Psychiatry Unit, Spedali Civili Brescia, Brescia, Italy
| | - Lucio Giordano
- Child Neurology and Psychiatry Unit, Spedali Civili Brescia, Brescia, Italy
| | - Chiara Pantaleoni
- Developmental Neurology Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Antonino Romeo
- Pediatric Neurology Unit and Epilepsy Center, 'Fatebenefratelli e Oftalmico' Hospital, Milan, Italy
| | - Alessia Arena
- Department of Clinical and Experimental Medicine, Regional Referral Center for Inborn Errors Metabolism, Pediatric Clinic, University of Catania, Catania, Italy
| | - Silvia Bonetti
- IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Neuropsichiatria dell'Età Pediatrica, Bologna, Italy
| | - Antonella Boni
- IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Neuropsichiatria dell'Età Pediatrica, Bologna, Italy
| | - Daniela Chiarello
- Department of Neurosciences, Center for Epilepsy Surgery "C. Munari,", Niguarda Hospital, Milan, Italy
| | - Veronica Di Pisa
- IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Neuropsichiatria dell'Età Pediatrica, Bologna, Italy; Department of Medical and Surgical Sciences (DIMEC), Sant'Orsola Hospital, University of Bologna, Bologna, Italy
| | - Roberta Epifanio
- Clinical Neurophysiology Unit, IRCCS E Medea Scientific Institute, Bosisio Parini, Lecco, Italy
| | - Francesca Faravelli
- Clinical Genetics, NE Thames Regional Genetics Service, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Erica Finardi
- Developmental Neurology Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Agata Fiumara
- Department of Clinical and Experimental Medicine, Regional Referral Center for Inborn Errors Metabolism, Pediatric Clinic, University of Catania, Catania, Italy
| | - Daniele Grioni
- Child Neurophysiological Unit, San Gerardo Hospital, Monza, Italy
| | - Isabella Mammi
- Medical Genetics Unit, Dolo General Hospital, Venezia, Italy
| | - Susanna Negrin
- Epilepsy and Clinical Neurophysiology Unit, Scientific Institute, IRCCS Eugenio Medea, Conegliano, Treviso, Italy
| | - Elisa Osanni
- Epilepsy and Clinical Neurophysiology Unit, Scientific Institute, IRCCS Eugenio Medea, Conegliano, Treviso, Italy
| | | | | | - Romana Rizzi
- Neurology Unit Department of Neuro-Motor Diseases Local Health Authority of Reggio Emilia-IRCCS Reggio Emilia, Reggio Emilia, Italy
| | | | - Luigi Tarani
- Department of Maternal and Child Health, Sapienza University of Rome, Rome, Italy
| | - Nicoletta Zanotta
- Clinical Neurophysiology Unit, IRCCS E Medea Scientific Institute, Bosisio Parini, Lecco, Italy
| | - Ada Dormi
- IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Neuropsichiatria dell'Età Pediatrica, Bologna, Italy
| | - Aglaia Vignoli
- Child Neuropsychiatry Unit, ASST Grande Ospedale Metropolitano Niguarda, Department of Health Sciences, University of Milan, Milan, Italy
| | - Mariapaola Canevini
- Child Neuropsychiatry Unit, Epilepsy Center, San Paolo Hospital, Department of Health Sciences, University of Milan, Milan, Italy
| | - Duccio M Cordelli
- IRCCS Istituto delle Scienze Neurologiche di Bologna, UOC Neuropsichiatria dell'Età Pediatrica, Bologna, Italy; Department of Medical and Surgical Sciences (DIMEC), Sant'Orsola Hospital, University of Bologna, Bologna, Italy
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24
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Lévesque M, Biagini G, de Curtis M, Gnatkovsky V, Pitsch J, Wang S, Avoli M. The pilocarpine model of mesial temporal lobe epilepsy: Over one decade later, with more rodent species and new investigative approaches. Neurosci Biobehav Rev 2021; 130:274-291. [PMID: 34437936 DOI: 10.1016/j.neubiorev.2021.08.020] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Revised: 08/17/2021] [Accepted: 08/21/2021] [Indexed: 01/19/2023]
Abstract
Fundamental work on the mechanisms leading to focal epileptic discharges in mesial temporal lobe epilepsy (MTLE) often rests on the use of rodent models in which an initial status epilepticus (SE) is induced by kainic acid or pilocarpine. In 2008 we reviewed how, following systemic injection of pilocarpine, the main subsequent events are the initial SE, the latent period, and the chronic epileptic state. Up to a decade ago, rats were most often employed and they were frequently analysed only behaviorally. However, the use of transgenic mice has revealed novel information regarding this animal model. Here, we review recent findings showing the existence of specific neuronal events during both latent and chronic states, and how optogenetic activation of specific cell populations modulate spontaneous seizures. We also address neuronal damage induced by pilocarpine treatment, the role of neuroinflammation, and the influence of circadian and estrous cycles. Updating these findings leads us to propose that the rodent pilocarpine model continues to represent a valuable tool for identifying the basic pathophysiology of MTLE.
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Affiliation(s)
- Maxime Lévesque
- Montreal Neurological Institute-Hospital and Departments of Neurology & Neurosurgery, McGill University, Montreal, QC, H3A 2B4, Canada
| | - Giuseppe Biagini
- Department of Biomedical, Metabolic and Neural Sciences, University of Modena & Reggio Emilia, 41100 Modena, Italy
| | - Marco de Curtis
- Epilepsy Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, 20133 Milano, Italy
| | - Vadym Gnatkovsky
- Epilepsy Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, 20133 Milano, Italy; Department of Epileptology, University Hospital Bonn, 53127 Bonn, Germany
| | - Julika Pitsch
- Department of Epileptology, University Hospital Bonn, 53127 Bonn, Germany
| | - Siyan Wang
- Montreal Neurological Institute-Hospital and Departments of Neurology & Neurosurgery, McGill University, Montreal, QC, H3A 2B4, Canada
| | - Massimo Avoli
- Montreal Neurological Institute-Hospital and Departments of Neurology & Neurosurgery, McGill University, Montreal, QC, H3A 2B4, Canada; Departments of Physiology, McGill University, Montreal, QC, H3A 2B4, Canada; Department of Experimental Medicine, Sapienza University of Rome, 00185 Roma, Italy.
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25
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K v1.1 channels mediate network excitability and feed-forward inhibition in local amygdala circuits. Sci Rep 2021; 11:15180. [PMID: 34312446 PMCID: PMC8313690 DOI: 10.1038/s41598-021-94633-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 07/14/2021] [Indexed: 01/15/2023] Open
Abstract
Kv1.1 containing potassium channels play crucial roles towards dampening neuronal excitability. Mice lacking Kv1.1 subunits (Kcna1−/−) display recurrent spontaneous seizures and often exhibit sudden unexpected death. Seizures in Kcna1−/− mice resemble those in well-characterized models of temporal lobe epilepsy known to involve limbic brain regions and spontaneous seizures result in enhanced cFos expression and neuronal death in the amygdala. Yet, the functional alterations leading to amygdala hyperexcitability have not been identified. In this study, we used Kcna1−/− mice to examine the contributions of Kv1.1 subunits to excitability in neuronal subtypes from basolateral (BLA) and central lateral (CeL) amygdala known to exhibit distinct firing patterns. We also analyzed synaptic transmission properties in an amygdala local circuit predicted to be involved in epilepsy-related comorbidities. Our data implicate Kv1.1 subunits in controlling spontaneous excitatory synaptic activity in BLA pyramidal neurons. In the CeL, Kv1.1 loss enhances intrinsic excitability and impairs inhibitory synaptic transmission, notably resulting in dysfunction of feed-forward inhibition, a critical mechanism for controlling spike timing. Overall, we find inhibitory control of CeL interneurons is reduced in Kcna1−/− mice suggesting that basal inhibitory network functioning is less able to prevent recurrent hyperexcitation related to seizures.
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26
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Yang F, Li J, Song Y, Zhao M, Niemeyer JE, Luo P, Li D, Lin W, Ma H, Schwartz TH. Mesoscopic Mapping of Ictal Neurovascular Coupling in Awake Behaving Mice Using Optical Spectroscopy and Genetically Encoded Calcium Indicators. Front Neurosci 2021; 15:704834. [PMID: 34366781 PMCID: PMC8343016 DOI: 10.3389/fnins.2021.704834] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 06/30/2021] [Indexed: 11/13/2022] Open
Abstract
Unambiguously identifying an epileptic focus with high spatial resolution is a challenge, especially when no anatomic abnormality can be detected. Neurovascular coupling (NVC)-based brain mapping techniques are often applied in the clinic despite a poor understanding of ictal NVC mechanisms, derived primarily from recordings in anesthetized animals with limited spatial sampling of the ictal core. In this study, we used simultaneous wide-field mesoscopic imaging of GCamp6f and intrinsic optical signals (IOS) to record the neuronal and hemodynamic changes during acute ictal events in awake, behaving mice. Similar signals in isoflurane-anesthetized mice were compared to highlight the unique characteristics of the awake condition. In awake animals, seizures were more focal at the onset but more likely to propagate to the contralateral hemisphere. The HbT signal, derived from an increase in cerebral blood volume (CBV), was more intense in awake mice. As a result, the “epileptic dip” in hemoglobin oxygenation became inconsistent and unreliable as a mapping signal. Our data indicate that CBV-based imaging techniques should be more accurate than blood oxygen level dependent (BOLD)-based imaging techniques for seizure mapping in awake behaving animals.
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Affiliation(s)
- Fan Yang
- Department of Neurology, The First Hospital of Jilin University, Changchun, China.,Department of Neurological Surgery, Brain and Mind Research Institute, New York Presbyterian Hospital, Weill Cornell Medicine of Cornell University, New York, NY, United States
| | - Jing Li
- Department of Neurology, The First Hospital of Jilin University, Changchun, China.,Department of Neurological Surgery, Brain and Mind Research Institute, New York Presbyterian Hospital, Weill Cornell Medicine of Cornell University, New York, NY, United States
| | - Yan Song
- School of Nursing, Beihua University, Jilin City, China
| | - Mingrui Zhao
- Department of Neurological Surgery, Brain and Mind Research Institute, New York Presbyterian Hospital, Weill Cornell Medicine of Cornell University, New York, NY, United States
| | - James E Niemeyer
- Department of Neurological Surgery, Brain and Mind Research Institute, New York Presbyterian Hospital, Weill Cornell Medicine of Cornell University, New York, NY, United States
| | - Peijuan Luo
- Department of Neurology, The First Hospital of Jilin University, Changchun, China.,Department of Neurological Surgery, Brain and Mind Research Institute, New York Presbyterian Hospital, Weill Cornell Medicine of Cornell University, New York, NY, United States
| | - Dan Li
- Department of Radiology, The First Hospital of Jilin University, Changchun, China
| | - Weihong Lin
- Department of Neurology, The First Hospital of Jilin University, Changchun, China
| | - Hongtao Ma
- Department of Neurological Surgery, Brain and Mind Research Institute, New York Presbyterian Hospital, Weill Cornell Medicine of Cornell University, New York, NY, United States
| | - Theodore H Schwartz
- Department of Neurological Surgery, Brain and Mind Research Institute, New York Presbyterian Hospital, Weill Cornell Medicine of Cornell University, New York, NY, United States
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27
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An inventory of basic research in temporal lobe epilepsy. Rev Neurol (Paris) 2021; 177:1069-1081. [PMID: 34176659 DOI: 10.1016/j.neurol.2021.02.390] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 01/26/2021] [Accepted: 02/05/2021] [Indexed: 12/25/2022]
Abstract
Temporal lobe epilepsy is a severe neurological disease, characterized by seizure occurrence and invalidating cognitive co-morbidities, which affects up to 1% of the adults. Roughly one third of the patients are resistant to any conventional pharmacological treatments. The last option in that case is the surgical removal of the epileptic focus, with no guarantee for clinical symptom alleviation. This state of affairs requests the identification of cellular or molecular targets for novel therapeutic approaches with limited side effects. Here we review some generalities about the disease as well as some of the most recent discoveries about the cellular and molecular mechanisms of TLE, and the latest perspectives for novel treatments.
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28
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Losi G, Gomez-Gonzalo M, Zonta M, Chiavegato A, Carmignoto G. Cellular and molecular mechanisms of new onset seizure generation. Aging Clin Exp Res 2021; 33:1713-1716. [PMID: 31732960 DOI: 10.1007/s40520-019-01396-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 10/19/2019] [Indexed: 12/19/2022]
Abstract
New onset epilepsy and seizures are common neurological disorders in aged people, second only to stroke and dementia. They are frequently related to other pathological conditions including stroke, trauma, tumors and neurological diseases whereas in about one-third of cases the origin is unknown. Besides the origin, the cellular and molecular events that suddenly trigger seizures are poorly defined. Using an acute model of seizure generation that better resembles new onset seizures, we studied GABAergic interneurons and astrocytes during seizure generation. We found that seizures are preceded by a GABAergic rhythmic hyperactivity that synchronizes pyramidal neurons by inducing a rebound spiking that favors seizures' onset. Furthermore, the intense activity in GABAergic interneurons evokes Ca2+ elevations in astrocytes that, by releasing glutamate, further excite neuronal network. Elucidating the cellular and molecular events that generate seizures may reveal new targets for treatment of new onset seizures and epilepsy.
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Affiliation(s)
- Gabriele Losi
- Neuroscience Institute, National Research Council (CNR), Viale Giuseppe Colombo 3, Padua, Italy.
- Department of Biomedical Science, University of Padua, via Ugo Bassi 58/B, Padua, Italy.
| | - Marta Gomez-Gonzalo
- Neuroscience Institute, National Research Council (CNR), Viale Giuseppe Colombo 3, Padua, Italy
- Department of Biomedical Science, University of Padua, via Ugo Bassi 58/B, Padua, Italy
| | - Micaela Zonta
- Neuroscience Institute, National Research Council (CNR), Viale Giuseppe Colombo 3, Padua, Italy
- Department of Biomedical Science, University of Padua, via Ugo Bassi 58/B, Padua, Italy
| | - Angela Chiavegato
- Department of Biomedical Science, University of Padua, via Ugo Bassi 58/B, Padua, Italy
| | - Giorgio Carmignoto
- Neuroscience Institute, National Research Council (CNR), Viale Giuseppe Colombo 3, Padua, Italy.
- Department of Biomedical Science, University of Padua, via Ugo Bassi 58/B, Padua, Italy.
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29
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Uva L, Aracri P, Forcaia G, de Curtis M. Mapping region-specific seizure-like patterns in the in vitro isolated guinea pig brain. Exp Neurol 2021; 342:113727. [PMID: 33930392 DOI: 10.1016/j.expneurol.2021.113727] [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: 02/12/2021] [Revised: 04/09/2021] [Accepted: 04/22/2021] [Indexed: 10/21/2022]
Abstract
Specific neurophysiological seizure patterns in patients with focal epilepsy depend on cerebral location and the underlying neuropathology. Location-specific patterns have been also reported in experimental models. Two focal seizure patterns, named p-type and l-type, typical of neocortical and mesial temporal regions were identified in both patients explored with intracerebral EEG and in animal models. These two patterns were recorded in the olfactory regions and in the entorhinal cortex after either 4AP or BMI administration. Here we mapped epileptiform activities in other cortices to verify the existence of specific epileptiform patterns. Field potentials were simultaneously recorded at multiple locations in olfactory, limbic and neocortical regions of the isolated guinea pig brain after arterial administration of either 4AP or BMI. Most neocortical areas did not generate new distinctive focal seizure-like event (SLE), beside the p-type and l-type patterns. Spiking activity was typically recorded after BMI in all new analyzed regions, whereas SLEs were commonly observed during 4AP perfusion. We confirmed the presence of reproducible region-specific epileptiform patterns in all explored cortical areas and demonstrated that strongly inter-connected areas generate similar SLEs. Our study suggests that p- and l-type SLE represent the most common focal seizure patterns during acute manipulations with pro-epileptic compounds.
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Affiliation(s)
- Laura Uva
- Epilepsy Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, via Amadeo 42, 20133 Milano, Italy.
| | - Patrizia Aracri
- Epilepsy Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, via Amadeo 42, 20133 Milano, Italy
| | - Greta Forcaia
- School of Medicine and Surgery, University of Milano-Bicocca, via Cadore 48, 20900 Monza, MB, Italy.
| | - Marco de Curtis
- Epilepsy Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, via Amadeo 42, 20133 Milano, Italy.
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30
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Arnal-Real C, Mahmoudzadeh M, Manoochehri M, Nourhashemi M, Wallois F. What Triggers the Interictal Epileptic Spike? A Multimodal Multiscale Analysis of the Dynamic of Synaptic and Non-synaptic Neuronal and Vascular Compartments Using Electrical and Optical Measurements. Front Neurol 2021; 12:596926. [PMID: 33643187 PMCID: PMC7907164 DOI: 10.3389/fneur.2021.596926] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 01/21/2021] [Indexed: 11/20/2022] Open
Abstract
Interictal spikes (IISs) may result from a disturbance of the intimate functional balance between various neuronal (synaptic and non-synaptic), vascular, and metabolic compartments. To better characterize the complex interactions within these compartments at different scales we developed a simultaneous multimodal-multiscale approach and measure their activity around the time of the IIS. We performed such measurements in an epileptic rat model (n = 43). We thus evaluated (1) synaptic dynamics by combining electrocorticography and multiunit activity recording in the time and time-frequency domain, (2) non-synaptic dynamics by recording modifications in light scattering induced by changes in the membrane configuration related to cell activity using the fast optical signal, and (3) vascular dynamics using functional near-infrared spectroscopy and, independently but simultaneously to the electrocorticography, the changes in cerebral blood flow using diffuse correlation spectroscopy. The first observed alterations in the measured signals occurred in the hemodynamic compartments a few seconds before the peak of the IIS. These hemodynamic changes were followed by changes in coherence and then synchronization between the deep and superficial neural networks in the 1 s preceding the IIS peaks. Finally, changes in light scattering before the epileptic spikes suggest a change in membrane configuration before the IIS. Our multimodal, multiscale approach highlights the complexity of (1) interactions between the various neuronal, vascular, and extracellular compartments, (2) neural interactions between various layers, (3) the synaptic mechanisms (coherence and synchronization), and (4) non-synaptic mechanisms that take place in the neuronal network around the time of the IISs in a very specific cerebral hemodynamic environment.
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Affiliation(s)
- Cristian Arnal-Real
- Inserm U1105, GRAMFC, CURS, Université de Picardie Jules Verne, Amiens, France
| | - Mahdi Mahmoudzadeh
- Inserm U1105, GRAMFC, CURS, Université de Picardie Jules Verne, Amiens, France
| | - Mana Manoochehri
- Inserm U1105, GRAMFC, CURS, Université de Picardie Jules Verne, Amiens, France
| | - Mina Nourhashemi
- Inserm U1105, GRAMFC, CURS, Université de Picardie Jules Verne, Amiens, France
| | - Fabrice Wallois
- Inserm U1105, GRAMFC, CURS, Université de Picardie Jules Verne, Amiens, France
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Breton VL, Dufour S, Chinvarun Y, Del Campo JM, Bardakjian BL, Carlen PL. Transitions between neocortical seizure and non-seizure-like states and their association with presynaptic glutamate release. Neurobiol Dis 2020; 146:105124. [PMID: 33010482 DOI: 10.1016/j.nbd.2020.105124] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 09/16/2020] [Accepted: 09/28/2020] [Indexed: 11/28/2022] Open
Abstract
The transition between seizure and non-seizure states in neocortical epileptic networks is governed by distinct underlying dynamical processes. Based on the gamma distribution of seizure and inter-seizure durations, over time, seizures are highly likely to self-terminate; whereas, inter-seizure durations have a low chance of transitioning back into a seizure state. Yet, the chance of a state transition could be formed by multiple overlapping, unknown synaptic mechanisms. To identify the relationship between the underlying synaptic mechanisms and the chance of seizure-state transitions, we analyzed the skewed histograms of seizure durations in human intracranial EEG and seizure-like events (SLEs) in local field potential activity from mouse neocortical slices, using an objective method for seizure state classification. While seizures and SLE durations were demonstrated to have a unimodal distribution (gamma distribution shape parameter >1), suggesting a high likelihood of terminating, inter-SLE intervals were shown to have an asymptotic exponential distribution (gamma distribution shape parameter <1), suggesting lower probability of cessation. Then, to test cellular mechanisms for these distributions, we studied the modulation of synaptic neurotransmission during, and between, the in vitro SLEs. Using simultaneous local field potential and whole-cell voltage clamp recordings, we found a suppression of presynaptic glutamate release at SLE termination, as demonstrated by electrically- and optogenetically-evoked excitatory postsynaptic currents (EPSCs), and focal hypertonic sucrose application. Adenosine A1 receptor blockade interfered with the suppression of this release, changing the inter-SLE shape parameter from asymptotic exponential to unimodal, altering the chance of state transition occurrence with time. These findings reveal a critical role for presynaptic glutamate release in determining the chance of neocortical seizure state transitions.
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Affiliation(s)
- Vanessa L Breton
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario M5S 1A8, Canada; Krembil Research Institute, Division of Fundamental Neurobiology, Toronto Western Hospital, Toronto, Ontario M5T 0S8, Canada.
| | - Suzie Dufour
- Krembil Research Institute, Division of Fundamental Neurobiology, Toronto Western Hospital, Toronto, Ontario M5T 0S8, Canada; National Optics Institute, Biophotonics, Quebec, Canada G1P 4S4
| | - Yotin Chinvarun
- Comprehensive Epilepsy Program and Neurology Unit, Phramongkutklao Hospital, Bangkok, Thailand
| | - Jose Martin Del Campo
- Department of Medicine (Neurology), University Health Network, Toronto, Ontario M5G 2C4, Canada
| | - Berj L Bardakjian
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada; Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario M5S 3G4, Canada
| | - Peter L Carlen
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario M5S 1A8, Canada; Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada; Krembil Research Institute, Division of Fundamental Neurobiology, Toronto Western Hospital, Toronto, Ontario M5T 0S8, Canada; Department of Medicine (Neurology), University Health Network, Toronto, Ontario M5G 2C4, Canada
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Multimodal Detection for Cryptogenic Epileptic Seizures Based on Combined Micro Sensors. BIOMED RESEARCH INTERNATIONAL 2020; 2020:5734932. [PMID: 32964037 PMCID: PMC7492941 DOI: 10.1155/2020/5734932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 07/24/2020] [Accepted: 08/17/2020] [Indexed: 12/02/2022]
Abstract
The cryptogenic epilepsy of the neocortex is a disease in which the seizure is accompanied by intense cerebral nerve electrical activities but the lesions are not observed. It is difficult to locate disease foci. Electrocorticography (ECoG) is one of the gold standards in seizure focus localization. This method detects electrical signals, and its limitations are inadequate resolution which is only 10 mm and lack of depth information. In order to solve these problems, our new method with implantable micro ultrasound transducer (MUT) and photoplethysmogram (PPG) device detects blood changes to achieve higher resolution and provide depth information. The basis of this method is the neurovascular coupling mechanism, which shows that intense neural activity leads to sufficient cerebral blood volume (CBV). The neurovascular coupling mechanism established the relationship between epileptic electrical signals and CBV. The existence of mechanism enables us to apply our new methods on the basis of ECoG. Phantom experiments and in vivo experiments were designed to verify the proposed method. The first phantom experiments designed a phantom with two channels at different depths, and the MUT was used to detect the depth where the blood concentration changed. The results showed that the MUT detected the blood concentration change at the depth of 12 mm, which is the position of the second channel. In the second phantom experiments where a PPG device and MUT were used to monitor the change of blood concentration in a thick tube, the results showed that the trend of superficial blood concentration change provided by the PPG device is the same as that provided by the MUT within the depth of 2.5 mm. Finally, in the verification of in vivo experiments, the blood concentration changes on the surface recorded by the PPG device and the changes at a certain depth recorded by the MUT all matched the seizure status shown by ECoG. These results confirmed the effectiveness of the combined micro sensors.
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Rathmann T, Khaleghi Ghadiri M, Stummer W, Gorji A. Spreading Depolarization Facilitates the Transition of Neuronal Burst Firing from Interictal to Ictal State. Neuroscience 2020; 441:176-183. [PMID: 32450296 DOI: 10.1016/j.neuroscience.2020.05.029] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 04/24/2020] [Accepted: 05/17/2020] [Indexed: 12/13/2022]
Abstract
The transition of neuronal burst firing from the interictal to ictal state contributes to seizure initiation in human temporal lobe epilepsy. The low-Mg2+ model of seizure is characterized by initial spontaneous interictal bursting events, which later developed into ictaform discharges. Both experimental and clinical studies point to a complex link between spreading depolarization (SD) and epileptiform field potentials (EFP), including SD-induced epileptic seizures. To investigate the mechanism of SD and EFP interactions, the effect of SD on the transition of interictal to ictal state in low-Mg2+ model of seizure was studied in the rat hippocampus in vitro. After the appearance of interictal activities, SD was elicited by local application of KCl. SD significantly increased the amplitude and duration of action potentials and after-hyperpolarization, and hyperpolarized the membrane potential. Furthermore, SD significantly increased the duration of interictal activities and the threshold potentials of interictal activities. In addition, SD significantly accelerated the transition from interictal to ictal state compared to the control tissues. Ictal activities after induction of SD exhibited a significantly longer duration. This study revealed that SD accelerates interictal-to-ictal transitions and facilitates development of ictaform discharges, possibly via the enhancement of neural synchronization, and points to the potential role of SD in seizure initiation.
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Affiliation(s)
- Thomas Rathmann
- Epilepsy Research Center, Westfälische Wilhelms-Universität Münster, Germany
| | | | - Walter Stummer
- Department of Neurosurgery, Westfälische Wilhelms-Universität Münster, Germany
| | - Ali Gorji
- Epilepsy Research Center, Westfälische Wilhelms-Universität Münster, Germany; Department of Neurosurgery, Westfälische Wilhelms-Universität Münster, Germany; Shefa Neuroscience Research Center, Khatam Alanbia Hospital, Tehran, Iran; Department of Neurology and Institute of Translational Neurology, Westfälische Wilhelms-Universität Münster, Germany; Neuroscience Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
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Chen LY, Lévesque M, Avoli M. KCC2 antagonism and gabaergic synchronization in the entorhinal cortex in the absence of ionotropic glutamatergic receptor signalling. Neuropharmacology 2020; 167:107982. [PMID: 32014449 DOI: 10.1016/j.neuropharm.2020.107982] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 01/17/2020] [Accepted: 01/28/2020] [Indexed: 12/17/2022]
Abstract
γ-Aminobutyric acid (GABA), which is released by interneurons, plays an active role in generating interictal epileptiform spikes during blockade of ionotropic glutamatergic signalling, but it remains unclear whether and how the K+-Cl- cotransporter 2 (KCC2) influences these paroxysmal events. Therefore, we employed tetrode recordings in the in vitro rat entorhinal cortex (EC) to analyze the effects of the KCC2 antagonist VU0463271 on 4-aminopyridine (4AP)-induced interictal spikes that were pharmacologically isolated by applying ionotropic glutamatergic receptor antagonists. After the addition of VU0463271, these interictal spikes continued to occur at similar rates as in control (i.e., during application of 4AP with ionotropic glutamatergic receptor antagonists) but were smaller and shorter. Despite the absence of ionotropic glutamatergic receptor signalling, both interneurons and principal cells increased their firing during interictal spikes. Moreover, we found that KCC2 antagonism increased interneuron firing but decreased principal cell firing during the interictal spike rising phase; in contrast, during the falling phase, interneuron firing decreased in the presence of VU0463271 while no change was observed in principal cell firing. Overall, our results show that KCC2 antagonism enhances interneuron excitability at the onset of interictal spikes generated by the EC neuronal networks during blockade of ionotropic glutamatergic transmission but disrupts later neuronal recruitment.
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Affiliation(s)
- Li-Yuan Chen
- Montreal Neurological Institute and Hospital, Departments of Neurology & Neurosurgery and of Physiology, McGill University, 3801 University Street, Montreal, H3A 2B4, QC, Canada
| | - Maxime Lévesque
- Montreal Neurological Institute and Hospital, Departments of Neurology & Neurosurgery and of Physiology, McGill University, 3801 University Street, Montreal, H3A 2B4, QC, Canada
| | - Massimo Avoli
- Montreal Neurological Institute and Hospital, Departments of Neurology & Neurosurgery and of Physiology, McGill University, 3801 University Street, Montreal, H3A 2B4, QC, Canada.
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Amakhin DV, Smolensky IV, Soboleva EB, Zaitsev AV. Paradoxical Anticonvulsant Effect of Cefepime in the Pentylenetetrazole Model of Seizures in Rats. Pharmaceuticals (Basel) 2020; 13:ph13050080. [PMID: 32357511 PMCID: PMC7281561 DOI: 10.3390/ph13050080] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 04/22/2020] [Accepted: 04/24/2020] [Indexed: 01/03/2023] Open
Abstract
Many β-lactam antibiotics, including cephalosporins, may cause neurotoxic and proconvulsant effects. The main molecular mechanism of such effects is considered to be γ-aminobutyric acid type a (GABAa) receptor blockade, leading to the suppression of GABAergic inhibition and subsequent overexcitation. We found that cefepime (CFP), a cephalosporin, has a pronounced antiepileptic effect in the pentylenetetrazole (PTZ)-induced seizure model by decreasing the duration and severity of the seizure and animal mortality. This effect was specific to the PTZ model. In line with findings of previous studies, CFP exhibited a proconvulsant effect in other models, including the maximal electroshock model and 4-aminopyridine model of epileptiform activity, in vitro. To determine the antiepileptic mechanism of CFP in the PTZ model, we used whole-cell patch-clamp recordings. We demonstrated that CFP or PTZ decreased the amplitude of GABAa receptor-mediated postsynaptic currents. PTZ also decreased the current decay time constant and temporal summation of synaptic responses. In contrast, CFP slightly increased the decay time constant and did not affect summation. When applied together, CFP prevented alterations to the summation of responses by PTZ, strongly reducing the effects of PTZ on repetitive inhibitory synaptic transmission. The latter may explain the antiepileptic effect of CFP in the PTZ model.
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Levinson S, Tran CH, Barry J, Viker B, Levine MS, Vinters HV, Mathern GW, Cepeda C. Paroxysmal Discharges in Tissue Slices From Pediatric Epilepsy Surgery Patients: Critical Role of GABA B Receptors in the Generation of Ictal Activity. Front Cell Neurosci 2020; 14:54. [PMID: 32265658 PMCID: PMC7099654 DOI: 10.3389/fncel.2020.00054] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 02/24/2020] [Indexed: 01/04/2023] Open
Abstract
In the present study, we characterized the effects of bath application of the proconvulsant drug 4-aminopyridine (4-AP) alone or in combination with GABAA and/or GABAB receptor antagonists, in cortical dysplasia (CD type I and CD type IIa/b), tuberous sclerosis complex (TSC), and non-CD cortical tissue samples from pediatric epilepsy surgery patients. Whole-cell patch clamp recordings in current and voltage clamp modes were obtained from cortical pyramidal neurons (CPNs), interneurons, and balloon/giant cells. In pyramidal neurons, bath application of 4-AP produced an increase in spontaneous synaptic activity as well as rhythmic membrane oscillations. In current clamp mode, these oscillations were generally depolarizing or biphasic and were accompanied by increased membrane conductance. In interneurons, membrane oscillations were consistently depolarizing and accompanied by bursts of action potentials. In a subset of balloon/giant cells from CD type IIb and TSC cases, respectively, 4-AP induced very low-amplitude, slow membrane oscillations that echoed the rhythmic oscillations from pyramidal neurons and interneurons. Bicuculline reduced the amplitude of membrane oscillations induced by 4-AP, indicating that they were mediated principally by GABAA receptors. 4-AP alone or in combination with bicuculline increased cortical excitability but did not induce seizure-like discharges. Ictal activity was observed in pyramidal neurons and interneurons from CD and TSC cases only when phaclofen, a GABAB receptor antagonist, was added to the 4-AP and bicuculline solution. These results emphasize the critical and permissive role of GABAB receptors in the transition to an ictal state in pediatric CD tissue and highlight the importance of these receptors as a potential therapeutic target in pediatric epilepsy.
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Affiliation(s)
- Simon Levinson
- IDDRC, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Conny H Tran
- IDDRC, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Joshua Barry
- IDDRC, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Brett Viker
- IDDRC, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Michael S Levine
- IDDRC, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Harry V Vinters
- Section of Neuropathology, Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States.,Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Gary W Mathern
- IDDRC, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States.,Department of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Carlos Cepeda
- IDDRC, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
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Yang F, Yang L, Wataya-Kaneda M, Teng L, Katayama I. Epilepsy in a melanocyte-lineage mTOR hyperactivation mouse model: A novel epilepsy model. PLoS One 2020; 15:e0228204. [PMID: 31978189 PMCID: PMC6980560 DOI: 10.1371/journal.pone.0228204] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 01/09/2020] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE To clarify the complex mechanism underlying epileptogeneis, a novel animal model was generated. METHODS In our previous research, we have generated a melanocyte-lineage mTOR hyperactivation mouse model (Mitf-M-Cre Tsc2 KO mice; cKO mice) to investigate mTOR pathway in melanogenesis regulation, markedly reduced skin pigmentation was observed. Very unexpectedly, spontaneous recurrent epilepsy was also developed in this mouse model. RESULTS Compared with control littermates, no change was found in either brain size or brain mass in cKO mice. Hematoxylin staining revealed no obvious aberrant histologic features in the whole brains of cKO mice. Histoimmunofluorescence staining and electron microscopy examination revealed markedly increased mTOR signaling and hyperproliferation of mitochondria in cKO mice, especially in the hippocampus. Furthermore, rapamycin treatment reversed these abnormalities. CONCLUSIONS This study suggests that our melanocyte-lineage mTOR hyperactivation mouse is a novel animal model of epilepsy, which may promote the progress of both epilepsy and neurophysiology research.
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Affiliation(s)
- Fei Yang
- Department of Dermatology, Course of Integrated Medicine, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Lingli Yang
- Department of Dermatology, Course of Integrated Medicine, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Mari Wataya-Kaneda
- Department of Dermatology, Course of Integrated Medicine, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Lanting Teng
- Department of Dermatology, Course of Integrated Medicine, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Ichiro Katayama
- Department of Dermatology, Course of Integrated Medicine, Graduate School of Medicine, Osaka University, Osaka, Japan
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Rich S, Chameh HM, Rafiee M, Ferguson K, Skinner FK, Valiante TA. Inhibitory Network Bistability Explains Increased Interneuronal Activity Prior to Seizure Onset. Front Neural Circuits 2020; 13:81. [PMID: 32009908 PMCID: PMC6972503 DOI: 10.3389/fncir.2019.00081] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2019] [Accepted: 12/17/2019] [Indexed: 01/02/2023] Open
Abstract
Recent experimental literature has revealed that GABAergic interneurons exhibit increased activity prior to seizure onset, alongside additional evidence that such activity is synchronous and may arise abruptly. These findings have led some to hypothesize that this interneuronal activity may serve a causal role in driving the sudden change in brain activity that heralds seizure onset. However, the mechanisms predisposing an inhibitory network toward increased activity, specifically prior to ictogenesis, without a permanent change to inputs to the system remain unknown. We address this question by comparing simulated inhibitory networks containing control interneurons and networks containing hyperexcitable interneurons modeled to mimic treatment with 4-Aminopyridine (4-AP), an agent commonly used to model seizures in vivo and in vitro. Our in silico study demonstrates that model inhibitory networks with 4-AP interneurons are more prone than their control counterparts to exist in a bistable state in which asynchronously firing networks can abruptly transition into synchrony driven by a brief perturbation. This transition into synchrony brings about a corresponding increase in overall firing rate. We further show that perturbations driving this transition could arise in vivo from background excitatory synaptic activity in the cortex. Thus, we propose that bistability explains the increase in interneuron activity observed experimentally prior to seizure via a transition from incoherent to coherent dynamics. Moreover, bistability explains why inhibitory networks containing hyperexcitable interneurons are more vulnerable to this change in dynamics, and how such networks can undergo a transition without a permanent change in the drive. We note that while our comparisons are between networks of control and ictogenic neurons, the conclusions drawn specifically relate to the unusual dynamics that arise prior to seizure, and not seizure onset itself. However, providing a mechanistic explanation for this phenomenon specifically in a pro-ictogenic setting generates experimentally testable hypotheses regarding the role of inhibitory neurons in pre-ictal neural dynamics, and motivates further computational research into mechanisms underlying a newly hypothesized multi-step pathway to seizure initiated by inhibition.
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Affiliation(s)
- Scott Rich
- Division of Clinical and Computational Neuroscience, Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Homeira Moradi Chameh
- Division of Clinical and Computational Neuroscience, Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Marjan Rafiee
- Division of Clinical and Computational Neuroscience, Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Katie Ferguson
- Division of Clinical and Computational Neuroscience, Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Frances K Skinner
- Division of Clinical and Computational Neuroscience, Krembil Research Institute, University Health Network, Toronto, ON, Canada.,Departments of Medicine (Neurology) and Physiology, University of Toronto, Toronto, ON, Canada
| | - Taufik A Valiante
- Division of Clinical and Computational Neuroscience, Krembil Research Institute, University Health Network, Toronto, ON, Canada.,Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada.,Institute of Medical Science, University of Toronto, Toronto, ON, Canada.,Division of Neurosurgery, Department of Surgery, University of Toronto, Toronto, ON, Canada.,Department of Electrical and Computer Engineering, University of Toronto, Toronto, ON, Canada
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Aygun H, Bilginoglu A. Effect of tadalafil and nitric oxide agonist sodium nitroprusside on penicillin-induced epileptiform activity. Neurol Res 2019; 42:39-46. [DOI: 10.1080/01616412.2019.1703166] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- Hatice Aygun
- Department of Physiology, Faculty of Medicine, TokatGaziosmanpasa University, Tokat, Turkey
| | - Ayça Bilginoglu
- Department of Biophysics, Faculty of Medicine, YıldırımBeyazıt University, Ankara, Turkey
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de Curtis M, Uva L, Lévesque M, Biella G, Avoli M. Piriform cortex ictogenicity in vitro. Exp Neurol 2019; 321:113014. [DOI: 10.1016/j.expneurol.2019.113014] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 05/07/2019] [Accepted: 07/15/2019] [Indexed: 02/05/2023]
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Cepeda C, Levinson S, Nariai H, Yazon VW, Tran C, Barry J, Oikonomou KD, Vinters HV, Fallah A, Mathern GW, Wu JY. Pathological high frequency oscillations associate with increased GABA synaptic activity in pediatric epilepsy surgery patients. Neurobiol Dis 2019; 134:104618. [PMID: 31629890 DOI: 10.1016/j.nbd.2019.104618] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 08/22/2019] [Accepted: 09/19/2019] [Indexed: 11/25/2022] Open
Abstract
Pathological high-frequency oscillations (HFOs), specifically fast ripples (FRs, >250 Hz), are pathognomonic of an active epileptogenic zone. However, the origin of FRs remains unknown. Here we explored the correlation between FRs recorded with intraoperative pre-resection electrocorticography (ECoG) and spontaneous synaptic activity recorded ex vivo from cortical tissue samples resected for the treatment of pharmacoresistant epilepsy. The cohort included 47 children (ages 0.22-9.99 yr) with focal cortical dysplasias (CD types I and II), tuberous sclerosis complex (TSC) and non-CD pathologies. Whole-cell patch clamp recordings were obtained from pyramidal neurons and interneurons in cortical regions that were positive or negative for pathological HFOs, defined as FR band oscillations (250-500 Hz) at ECoG. The frequency of spontaneous excitatory and inhibitory postsynaptic currents (sEPSCs and IPSCs, respectively) was compared between HFO+ and HFO- regions. Regardless of pathological substrate, regions positive for FRs displayed significantly increased frequencies of sIPSCs compared with regions negative for FRs. In contrast, the frequency of sEPSCs was similar in both regions. In about one third of cases (n = 17), pacemaker GABA synaptic activity (PGA) was observed. In the vast majority (n = 15), PGA occurred in HFO+ areas. Further, fast-spiking interneurons displayed signs of hyperexcitability exclusively in HFO+ areas. These results indicate that, in pediatric epilepsy patients, increased GABA synaptic activity is associated with interictal FRs in the epileptogenic zone and suggest an active role of GABAergic interneurons in the generation of pathological HFOs. Increased GABA synaptic activity could serve to dampen excessive excitability of cortical pyramidal neurons in the epileptogenic zone, but it could also promote neuronal network synchrony.
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Affiliation(s)
- Carlos Cepeda
- IDDRC, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, CA, USA.
| | - Simon Levinson
- IDDRC, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, CA, USA
| | - Hiroki Nariai
- Division of Pediatric Neurology, Mattel Children's Hospital, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, CA, USA
| | - Vannah-Wila Yazon
- IDDRC, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, CA, USA
| | - Conny Tran
- IDDRC, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, CA, USA
| | - Joshua Barry
- IDDRC, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, CA, USA
| | - Katerina D Oikonomou
- IDDRC, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, CA, USA
| | - Harry V Vinters
- Section of Neuropathology, Department of Pathology and Laboratory Medicine and Department of Neurology, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, CA, USA
| | - Aria Fallah
- Department of Neurosurgery, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, CA, USA
| | - Gary W Mathern
- IDDRC, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, CA, USA; Department of Neurosurgery, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, CA, USA
| | - Joyce Y Wu
- Division of Pediatric Neurology, Mattel Children's Hospital, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, CA, USA
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Li J, Grinenko O, Mosher JC, Gonzalez-Martinez J, Leahy RM, Chauvel P. Learning to define an electrical biomarker of the epileptogenic zone. Hum Brain Mapp 2019; 41:429-441. [PMID: 31609058 PMCID: PMC7268034 DOI: 10.1002/hbm.24813] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 09/17/2019] [Accepted: 09/19/2019] [Indexed: 01/07/2023] Open
Abstract
The role of fast activity as a potential biomarker in localization of the epileptogenic zone (EZ) remains controversial due to recently reported unsatisfactory performance. We recently identified a “fingerprint” of the EZ as a time‐frequency pattern that is defined by a combination of preictal spike(s), fast oscillatory activity, and concurrent suppression of lower frequencies. Here we examine the generalizability of the fingerprint in application to an independent series of patients (11 seizure‐free and 13 non‐seizure‐free after surgery) and show that the fingerprint can also be identified in seizures with lower frequency (such as beta) oscillatory activity. In the seizure‐free group, only 5 of 47 identified EZ contacts were outside the resection. In contrast, in the non‐seizure‐free group, 104 of 142 identified EZ contacts were outside the resection. We integrated the fingerprint prediction with the subject's MR images, thus providing individualized anatomical estimates of the EZ. We show that these fingerprint‐based estimates in seizure‐free patients are almost always inside the resection. On the other hand, for a large fraction of the nonseizure‐free patients the estimated EZ was not well localized and was partially or completely outside the resection, which may explain surgical failure in such cases. We also show that when mapping fast activity alone onto MR images, the EZ was often over‐estimated, indicating a reduced discriminative ability for fast activity relative to the full fingerprint for localization of the EZ.
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Affiliation(s)
- Jian Li
- Signal and Image Processing Institute, University of Southern California, Los Angeles, California
| | - Olesya Grinenko
- Epilepsy Center, Cleveland Clinic Neurological Institute, Cleveland, Ohio
| | - John C Mosher
- Department of Neurology, University of Texas Health Science Center at Houston, Houston, Texas
| | | | - Richard M Leahy
- Signal and Image Processing Institute, University of Southern California, Los Angeles, California
| | - Patrick Chauvel
- Epilepsy Center, Cleveland Clinic Neurological Institute, Cleveland, Ohio
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Köhling R. Translational perspectives: Interneurones start seizures. J Physiol 2019; 597:5525-5526. [PMID: 31603536 DOI: 10.1113/jp278966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 10/09/2019] [Indexed: 11/08/2022] Open
Affiliation(s)
- Rüdiger Köhling
- Oscar-Langendorff-Institute of Physiology, Rostock University Medical Center, Rostock, Germany
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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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Lévesque M, Chen LY, Etter G, Shiri Z, Wang S, Williams S, Avoli M. Paradoxical effects of optogenetic stimulation in mesial temporal lobe epilepsy. Ann Neurol 2019; 86:714-728. [PMID: 31393618 DOI: 10.1002/ana.25572] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 07/31/2019] [Accepted: 08/04/2019] [Indexed: 12/19/2022]
Abstract
OBJECTIVE To establish the effects induced by long-term, unilateral stimulation of parvalbumin (PV)-positive interneurons on seizures, interictal spikes, and high-frequency oscillations (80-500Hz) occurring after pilocarpine-induced status epilepticus (SE)-a proven model of mesial temporal lobe epilepsy (MTLE)-in transgenic mice expressing or not expressing ChR2. METHODS PV-ChR2 (n = 6) and PV-Cre (n = 6) mice were treated with pilocarpine to induce SE. Three hours after SE onset, unilateral optogenetic stimulation (450nm, 25mW, 20-millisecond pulses delivered at 8Hz for 30 seconds every 2 minutes) of CA3 PV-positive interneurons was implemented for 14 continuous days in both groups. RESULTS Rates of seizures (p < 0.01), interictal spikes (p < 0.001), and interictal spikes with fast ripples (250-500Hz) (p < 0.001) were lower in PV-ChR2 than in PV-Cre mice. Ripples (80-200Hz) occurring outside of interictal spikes had higher rates in the PV-ChR2 group (p < 0.01), whereas isolated fast ripples had lower rates (p < 0.01). However, seizure probability was higher during optogenetic stimulation in PV-ChR2 compared to PV-Cre animals (p < 0.05). INTERPRETATION Our findings show that the unilateral activation of CA3 PV-positive interneurons exerts anti-ictogenic effects associated with decreased rates of interictal spikes and fast ripples in this MTLE model. However, PV-positive interneuron stimulation can paradoxically trigger seizures in epileptic animals, supporting the notion that γ-aminobutyric acid type A signaling can also initiate ictogenesis. ANN NEUROL 2019;86:714-728.
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Affiliation(s)
- Maxime Lévesque
- Montreal Neurological Institute and Department of Neurology and Neurosurgery, and Department of Physiology, McGill University, Montreal, Quebec, Canada
| | - Li-Yuan Chen
- Montreal Neurological Institute and Department of Neurology and Neurosurgery, and Department of Physiology, McGill University, Montreal, Quebec, Canada
| | - Guillaume Etter
- Douglas Mental Health University Institute, McGill University, Montreal, Quebec, Canada
| | - Zahra Shiri
- Montreal Neurological Institute and Department of Neurology and Neurosurgery, and Department of Physiology, McGill University, Montreal, Quebec, Canada
| | - Siyan Wang
- Montreal Neurological Institute and Department of Neurology and Neurosurgery, and Department of Physiology, McGill University, Montreal, Quebec, Canada
| | - Sylvain Williams
- Douglas Mental Health University Institute, McGill University, Montreal, Quebec, Canada
| | - Massimo Avoli
- Montreal Neurological Institute and Department of Neurology and Neurosurgery, and Department of Physiology, McGill University, Montreal, Quebec, Canada
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Woolfe M, Prime D, Gillinder L, Rowlands D, O'keefe S, Dionisio S. Automatic detection of the epileptogenic zone: An application of the fingerprint of epilepsy. J Neurosci Methods 2019; 325:108347. [PMID: 31330159 DOI: 10.1016/j.jneumeth.2019.108347] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 07/04/2019] [Accepted: 07/04/2019] [Indexed: 11/16/2022]
Abstract
BACKGROUND The successful delineation of the epileptogenic zone in epilepsy monitoring is crucial for achieving seizure freedom after epilepsy surgery. NEW METHOD We aim to improve epileptogenic zone localization by utilizing a computer-assisted tool for the automated grading of the seizure activity recorded in various locations for 20 patients undergoing stereo electroencephalography. Their epileptic seizures were processed to extract two potential biomarkers. The concentration of these biomarkers from within each patient's implantation were then graded to identify their epileptogenic zone and were compared to the clinical assessment. RESULTS Our technique was capable of ranking the clinically defined epileptogenic zone with high accuracy, above 95%, with a true to false positive ratio of 1:1.52, and was effective with both temporal and extra-temporal onset epilepsies. COMPARISON WITH EXISTING METHOD We compared our method to two other groups performing localization using similar biomarkers. Our classification metrics, sensitivity and precision together were comparable to both groups and our overall accuracy from a larger population was also higher then both. CONCLUSIONS Our method is highly accurate, automated and non-parametric providing clinicians another tool that can be used to help identify the epileptogenic zone in patients undergoing the stereo electroencephalography procedure for epilepsy monitoring.
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Affiliation(s)
- Matthew Woolfe
- Advanced Epilepsy Unit, Mater Adult Hospital Brisbane, Queensland, 4101, Australia; School of Engineering and Built Environment, Griffith University, Queensland, 4111, Australia.
| | - David Prime
- Advanced Epilepsy Unit, Mater Adult Hospital Brisbane, Queensland, 4101, Australia; School of Engineering and Built Environment, Griffith University, Queensland, 4111, Australia
| | - Lisa Gillinder
- Advanced Epilepsy Unit, Mater Adult Hospital Brisbane, Queensland, 4101, Australia
| | - David Rowlands
- School of Engineering and Built Environment, Griffith University, Queensland, 4111, Australia
| | - Steven O'keefe
- School of Engineering and Built Environment, Griffith University, Queensland, 4111, Australia
| | - Sasha Dionisio
- Advanced Epilepsy Unit, Mater Adult Hospital Brisbane, Queensland, 4101, Australia
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Liou JY, Ma H, Wenzel M, Zhao M, Baird-Daniel E, Smith EH, Daniel A, Emerson R, Yuste R, Schwartz TH, Schevon CA. Role of inhibitory control in modulating focal seizure spread. Brain 2019; 141:2083-2097. [PMID: 29757347 DOI: 10.1093/brain/awy116] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2017] [Accepted: 03/04/2018] [Indexed: 11/12/2022] Open
Abstract
Focal seizure propagation is classically thought to be spatially contiguous. However, distribution of seizures through a large-scale epileptic network has been theorized. Here, we used a multielectrode array, wide field calcium imaging, and two-photon calcium imaging to study focal seizure propagation pathways in an acute rodent neocortical 4-aminopyridine model. Although ictal neuronal bursts did not propagate beyond a 2-3-mm region, they were associated with hemisphere-wide field potential fluctuations and parvalbumin-positive interneuron activity outside the seizure focus. While bicuculline surface application enhanced contiguous seizure propagation, focal bicuculline microinjection at sites distant to the 4-aminopyridine focus resulted in epileptic network formation with maximal activity at the two foci. Our study suggests that both classical and epileptic network propagation can arise from localized inhibition defects, and that the network appearance can arise in the context of normal brain structure without requirement for pathological connectivity changes between sites.
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Affiliation(s)
- Jyun-You Liou
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA
| | - Hongtao Ma
- Department of Neurological Surgery, Feil Family Brain and Mind Research Institute, Sackler Brain and Spine Institute, Weill Cornell Medical College, New York, NY, USA
| | - Michael Wenzel
- Neurotechnology Center, Department of Biological Sciences, Columbia University, New York, NY, USA; Department of Neuroscience, Columbia University, New York, NY, USA
| | - Mingrui Zhao
- Department of Neurological Surgery, Feil Family Brain and Mind Research Institute, Sackler Brain and Spine Institute, Weill Cornell Medical College, New York, NY, USA
| | - Eliza Baird-Daniel
- Department of Neurological Surgery, Feil Family Brain and Mind Research Institute, Sackler Brain and Spine Institute, Weill Cornell Medical College, New York, NY, USA
| | - Elliot H Smith
- Department of Neurological Surgery, Columbia University Medical Center, New York, NY, USA
| | - Andy Daniel
- Department of Neurological Surgery, Feil Family Brain and Mind Research Institute, Sackler Brain and Spine Institute, Weill Cornell Medical College, New York, NY, USA
| | - Ronald Emerson
- Hospital for Special Surgery, Weill Cornell Medical College, 535 East 70th Street, New York, NY, USA
| | - Rafael Yuste
- Neurotechnology Center, Department of Biological Sciences, Columbia University, New York, NY, USA; Department of Neuroscience, Columbia University, New York, NY, USA
| | - Theodore H Schwartz
- Department of Neurological Surgery, Feil Family Brain and Mind Research Institute, Sackler Brain and Spine Institute, Weill Cornell Medical College, New York, NY, USA
| | - Catherine A Schevon
- Department of Neurology, Columbia University Medical Center, New York, New York, USA
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Inhibition and oscillations in the human brain tissue in vitro. Neurobiol Dis 2019; 125:198-210. [DOI: 10.1016/j.nbd.2019.02.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 12/22/2018] [Accepted: 02/07/2019] [Indexed: 01/22/2023] Open
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49
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de Curtis M, Librizzi L, Uva L, Gnatkovsky V. GABAA receptor-mediated networks during focal seizure onset and progression in vitro. Neurobiol Dis 2019; 125:190-197. [DOI: 10.1016/j.nbd.2019.02.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 01/08/2019] [Accepted: 02/07/2019] [Indexed: 02/02/2023] Open
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50
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Li L, Bragin A, Staba R, Engel J. Unit firing and oscillations at seizure onset in epileptic rodents. Neurobiol Dis 2019; 127:382-389. [PMID: 30928646 DOI: 10.1016/j.nbd.2019.03.027] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 03/04/2019] [Accepted: 03/26/2019] [Indexed: 01/27/2023] Open
Abstract
Epileptic seizures result from a variety of pathophysiological processes, evidenced by different electrographic ictal onset patterns, as seen on direct brain recordings. The two most common electrographic patterns of focal ictal onset in patients are hypersynchronous (HYP) and low-voltage fast (LVF). Whereas LVF ictal onsets were believed to result from disinhibition; based on similarities with absence seizures, focal HYP ictal onsets were believed to result from increased synchronizing inhibition. Recent findings, however, suggest the differences between these seizure onset types are more complicated and, in some cases, the opposite of these concepts are true. The following review presents evidence that a reduction of tonic inhibition on small pathologically interconnected neuron (PIN) clusters generating pathological high-frequency oscillations (pHFOs), which reflect abnormal synchronously bursting neurons may be the cause of HYP ictal onsets. Increased inhibition preceding LVF ictal onsets are discussed in other reviews in this issue. We postulate that neuronal cell loss following epileptogenic insults can result in structural reorganization, giving rise to small PIN clusters, which generate pHFOs. These clusters have a heterogeneous distribution and are spatially stable over time. Studies have demonstrated that a transient reduction in tonic inhibition causes these clusters to increase in size. This could result in consolidation and synchronization of pHFOs until a critical mass leads to propagation of HYP ictal discharges. Viewed within a network neuroscience framework, local disturbances such as PIN clusters are likely to contribute to large-scale brain network alterations: a better understanding of these epileptogenic networks promises to elucidate mechanisms of ictogenesis, epileptogenesis, and certain comorbidities of epilepsy.
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Affiliation(s)
- Lin Li
- Department of Neurology, University of California, Los Angeles, CA, USA
| | - Anatol Bragin
- Department of Neurology, University of California, Los Angeles, CA, USA; Brain Research Institute, University of California, Los Angeles, CA, USA
| | - Richard Staba
- Department of Neurology, University of California, Los Angeles, CA, USA
| | - Jerome Engel
- Department of Neurology, University of California, Los Angeles, CA, USA; Brain Research Institute, University of California, Los Angeles, CA, USA; Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA; Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
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