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Frauscher B, Mansilla D, Abdallah C, Astner-Rohracher A, Beniczky S, Brazdil M, Gnatkovsky V, Jacobs J, Kalamangalam G, Perucca P, Ryvlin P, Schuele S, Tao J, Wang Y, Zijlmans M, McGonigal A. Learn how to interpret and use intracranial EEG findings. Epileptic Disord 2024; 26:1-59. [PMID: 38116690 DOI: 10.1002/epd2.20190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 10/21/2023] [Accepted: 11/29/2023] [Indexed: 12/21/2023]
Abstract
Epilepsy surgery is the therapy of choice for many patients with drug-resistant focal epilepsy. Recognizing and describing ictal and interictal patterns with intracranial electroencephalography (EEG) recordings is important in order to most efficiently leverage advantages of this technique to accurately delineate the seizure-onset zone before undergoing surgery. In this seminar in epileptology, we address learning objective "1.4.11 Recognize and describe ictal and interictal patterns with intracranial recordings" of the International League against Epilepsy curriculum for epileptologists. We will review principal considerations of the implantation planning, summarize the literature for the most relevant ictal and interictal EEG patterns within and beyond the Berger frequency spectrum, review invasive stimulation for seizure and functional mapping, discuss caveats in the interpretation of intracranial EEG findings, provide an overview on special considerations in children and in subdural grids/strips, and review available quantitative/signal analysis approaches. To be as practically oriented as possible, we will provide a mini atlas of the most frequent EEG patterns, highlight pearls for its not infrequently challenging interpretation, and conclude with two illustrative case examples. This article shall serve as a useful learning resource for trainees in clinical neurophysiology/epileptology by providing a basic understanding on the concepts of invasive intracranial EEG.
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Affiliation(s)
- B Frauscher
- Department of Neurology, Duke University Medical Center and Department of Biomedical Engineering, Duke Pratt School of Engineering, Durham, North Carolina, USA
- Analytical Neurophysiology Lab, Montreal Neurological Institute and Hospital, Montreal, Québec, Canada
| | - D Mansilla
- Analytical Neurophysiology Lab, Montreal Neurological Institute and Hospital, Montreal, Québec, Canada
- Neurophysiology Unit, Institute of Neurosurgery Dr. Asenjo, Santiago, Chile
| | - C Abdallah
- Analytical Neurophysiology Lab, Montreal Neurological Institute and Hospital, Montreal, Québec, Canada
| | - A Astner-Rohracher
- Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria
| | - S Beniczky
- Danish Epilepsy Centre, Dianalund, Denmark
- Aarhus University, Aarhus, Denmark
| | - M Brazdil
- Brno Epilepsy Center, Department of Neurology, St. Anne's University Hospital and Medical Faculty of Masaryk University, Member of the ERN-EpiCARE, Brno, Czechia
- Behavioral and Social Neuroscience Research Group, Central European Institute of Technology, Masaryk University, Brno, Czechia
| | - V Gnatkovsky
- Department of Epileptology, University Hospital Bonn, Bonn, Germany
| | - J Jacobs
- Department of Paediatrics and Department of Neuroscience, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Hotchkiss Brain Institute and Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada
| | - G Kalamangalam
- Department of Neurology, University of Florida, Gainesville, Florida, USA
- Wilder Center for Epilepsy Research, University of Florida, Gainesville, Florida, USA
| | - P Perucca
- Epilepsy Research Centre, Department of Medicine (Austin Health), University of Melbourne, Melbourne, Victoria, Australia
- Bladin-Berkovic Comprehensive Epilepsy Program, Department of Neurology, Austin Health, Melbourne, Victoria, Australia
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Victoria, Australia
- Department of Neurology, Alfred Health, Melbourne, Victoria, Australia
- Department of Neurology, Royal Melbourne Hospital, Melbourne, Victoria, Australia
| | - P Ryvlin
- Department of Clinical Neurosciences, CHUV, Lausanne University Hospital, Lausanne, Switzerland
| | - S Schuele
- Department of Neurology, Feinberg School of Medicine, Northwestern Memorial Hospital, Chicago, Illinois, USA
| | - J Tao
- Department of Neurology, The University of Chicago, Chicago, Illinois, USA
| | - Y Wang
- Department of Epileptology, University Hospital Bonn, Bonn, Germany
- Wilder Center for Epilepsy Research, University of Florida, Gainesville, Florida, USA
| | - M Zijlmans
- Department of Neurology and Neurosurgery, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht, the Netherlands
- Stichting Epilepsie Instellingen Nederland (SEIN), Heemstede, The Netherlands
| | - A McGonigal
- Department of Neurosciences, Mater Misericordiae Hospital, Brisbane, Queensland, Australia
- Mater Research Institute, Faculty of Medicine, University of Queensland, St Lucia, Queensland, Australia
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2
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Jiruska P, Freestone D, Gnatkovsky V, Wang Y. An update on the seizures beget seizures theory. Epilepsia 2023; 64 Suppl 3:S13-S24. [PMID: 37466948 DOI: 10.1111/epi.17721] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 07/17/2023] [Accepted: 07/17/2023] [Indexed: 07/20/2023]
Abstract
Seizures beget seizures is a longstanding theory that proposed that seizure activity can impact the structural and functional properties of the brain circuits in ways that contribute to epilepsy progression and the future occurrence of seizures. Originally proposed by Gowers, this theory continues to be quoted in the pathophysiology of epilepsy. We critically review the existing data and observations on the consequences of recurrent seizures on brain networks and highlight a range of factors that speak for and against the theory. The existing literature demonstrates clearly that ictal activity, especially if recurrent, induces molecular, structural, and functional changes including cell loss, connectivity reorganization, changes in neuronal behavior, and metabolic alterations. These changes have the potential to modify the seizure threshold, contribute to disease progression, and recruit wider areas of the epileptic network into epileptic activity. Repeated seizure activity may, thus, act as a pathological positive-feedback mechanism that increases seizure likelihood. On the other hand, the time course of self-limited epilepsies and the presence of seizure remission in two thirds of epilepsy cases and various chronic epilepsy models oppose the theory. Experimental work showed that seizures could induce neural changes that increase the seizure threshold and decrease the risk of a subsequent seizure. Due to the complex nature of epilepsies, it is wrong to consider only seizures as the key factor responsible for disease progression. Epilepsy worsening can be attributed to the various forms of interictal epileptiform activity or underlying disease mechanisms. Although seizure activity can negatively impact brain structure and function, the "seizures beget seizures" theory should not be used dogmatically but with extreme caution.
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Affiliation(s)
- Premysl Jiruska
- Department of Physiology, Second Faculty of Medicine, Charles University, Prague, Czech Republic
| | | | - Vadym Gnatkovsky
- Department of Epileptology, University Hospital Bonn, Bonn, Germany
| | - Yujiang Wang
- Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
- Interdisciplinary Computing and Complex BioSystems Group, School of Computing Science, Newcastle University, Newcastle upon Tyne, UK
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3
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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4
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Jablonski J, Hoffmann L, Blümcke I, Fejtová A, Uebe S, Ekici AB, Gnatkovsky V, Kobow K. Experimental Epileptogenesis in a Cell Culture Model of Primary Neurons from Rat Brain: A Temporal Multi-Scale Study. Cells 2021; 10:cells10113004. [PMID: 34831225 PMCID: PMC8616120 DOI: 10.3390/cells10113004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 10/27/2021] [Accepted: 11/02/2021] [Indexed: 12/24/2022] Open
Abstract
Understanding seizure development requires an integrated knowledge of different scales of organization of epileptic networks. We developed a model of “epilepsy-in-a-dish” based on dissociated primary neuronal cells from neonatal rat hippocampus. We demonstrate how a single application of glutamate stimulated neurons to generate spontaneous synchronous spiking activity with further progression into spontaneous seizure-like events after a distinct latency period. By computational analysis, we compared the observed neuronal activity in vitro with intracranial electroencephalography (EEG) data recorded from epilepsy patients and identified strong similarities, including a related sequence of events with defined onset, progression, and termination. Next, a link between the neurophysiological changes with network composition and cellular structure down to molecular changes was established. Temporal development of epileptiform network activity correlated with increased neurite outgrowth and altered branching, increased ratio of glutamatergic over GABAergic synapses, and loss of calbindin-positive interneurons, as well as genome-wide alterations in DNA methylation. Differentially methylated genes were engaged in various cellular activities related to cellular structure, intracellular signaling, and regulation of gene expression. Our data provide evidence that a single short-term excess of glutamate is sufficient to induce a cascade of events covering different scales from molecule- to network-level, all of which jointly contribute to seizure development.
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Affiliation(s)
- Janos Jablonski
- Department of Neuropathology, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany; (J.J.); (L.H.); (I.B.)
| | - Lucas Hoffmann
- Department of Neuropathology, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany; (J.J.); (L.H.); (I.B.)
| | - Ingmar Blümcke
- Department of Neuropathology, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany; (J.J.); (L.H.); (I.B.)
| | - Anna Fejtová
- Department of Psychiatry and Psychotherapy, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany;
| | - Steffen Uebe
- NGS Core Unit, Institute of Human Genetics, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany; (S.U.); (A.B.E.)
| | - Arif B. Ekici
- NGS Core Unit, Institute of Human Genetics, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany; (S.U.); (A.B.E.)
| | - Vadym Gnatkovsky
- Department of Epileptology, University Hospital Bonn, 53127 Bonn, Germany;
| | - Katja Kobow
- Department of Neuropathology, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany; (J.J.); (L.H.); (I.B.)
- Correspondence: ; Tel.: +49-9131-8522859
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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: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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6
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Paudel YN, Angelopoulou E, Piperi C, Gnatkovsky V, Othman I, Shaikh MF. From the Molecular Mechanism to Pre-clinical Results: Anti-epileptic Effects of Fingolimod. Curr Neuropharmacol 2021; 18:1126-1137. [PMID: 32310049 PMCID: PMC7709153 DOI: 10.2174/1570159x18666200420125017] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 03/13/2020] [Accepted: 04/14/2020] [Indexed: 02/08/2023] Open
Abstract
Epilepsy is a devastating neurological condition characterized by long-term tendency to generate unprovoked seizures, affecting around 1-2% of the population worldwide. Epilepsy is a serious health concern which often associates with other neurobehavioral comorbidities that further worsen disease conditions. Despite tremendous research, the mainstream anti-epileptic drugs (AEDs) exert only symptomatic relief leading to 30% of untreatable patients. This reflects the complexity of the disease pathogenesis and urges the precise understanding of underlying mechanisms in order to explore novel therapeutic strategies that might alter the disease progression as well as minimize the epilepsy-associated comorbidities. Unfortunately, the development of novel AEDs might be a difficult process engaging huge funds, tremendous scientific efforts and stringent regulatory compliance with a possible chance of end-stage drug failure. Hence, an alternate strategy is drug repurposing, where anti-epileptic effects are elicited from drugs that are already used to treat non-epileptic disorders. Herein, we provide evidence of the anti-epileptic effects of Fingolimod (FTY720), a modulator of sphingosine-1-phosphate (S1P) receptor, USFDA approved already for Relapsing-Remitting Multiple Sclerosis (RRMS). Emerging experimental findings suggest that Fingolimod treatment exerts disease-modifying anti-epileptic effects based on its anti-neuroinflammatory properties, potent neuroprotection, anti-gliotic effects, myelin protection, reduction of mTOR signaling pathway and activation of microglia and astrocytes. We further discuss the underlying molecular crosstalk associated with the anti-epileptic effects of Fingolimod and provide evidence for repurposing Fingolimod to overcome the limitations of current AEDs.
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Affiliation(s)
- Yam Nath Paudel
- Neuropharmacology Research Laboratory, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Bandar Sunway, Selangor, Malaysia
| | - Efthalia Angelopoulou
- Department of Biological Chemistry, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Christina Piperi
- Department of Biological Chemistry, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Vadym Gnatkovsky
- Unit of Epileptology and Experimental Neurophysiology, Fondazione Istituto Neurologico Carlo Besta, 20133 Milan, Italy
| | - Iekhsan Othman
- Neuropharmacology Research Laboratory, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Bandar Sunway, Selangor, Malaysia
| | - Mohd Farooq Shaikh
- Neuropharmacology Research Laboratory, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Bandar Sunway, Selangor, Malaysia
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Pitsch J, van Loo KMJ, Gallus M, Dik A, Kamalizade D, Baumgart AK, Gnatkovsky V, Müller JA, Opitz T, Hicking G, Naik VN, Wachsmuth L, Faber C, Surges R, Kurts C, Schoch S, Melzer N, Becker AJ. CD8 + T-Lymphocyte-Driven Limbic Encephalitis Results in Temporal Lobe Epilepsy. Ann Neurol 2021; 89:666-685. [PMID: 33368582 DOI: 10.1002/ana.26000] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 12/22/2020] [Accepted: 12/22/2020] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Limbic encephalitis (LE) comprises a spectrum of inflammatory changes in affected brain structures including the presence of autoantibodies and lymphoid cells. However, the potential of distinct lymphocyte subsets alone to elicit key clinicopathological sequelae of LE potentially inducing temporal lobe epilepsy (TLE) with chronic spontaneous seizures and hippocampal sclerosis (HS) is unresolved. METHODS Here, we scrutinized pathogenic consequences emerging from CD8+ T cells targeting hippocampal neurons by recombinant adeno-associated virus-mediated expression of the model-autoantigen ovalbumin (OVA) in CA1 neurons of OT-I/RAG1-/- mice (termed "OVA-CD8+ LE model"). RESULTS Viral-mediated antigen transfer caused dense CD8+ T cell infiltrates confined to the hippocampal formation starting on day 5 after virus transduction. Flow cytometry indicated priming of CD8+ T cells in brain-draining lymph nodes preceding hippocampal invasion. At the acute model stage, the inflammatory process was accompanied by frequent seizure activity and impairment of hippocampal memory skills. Magnetic resonance imaging scans at day 7 of the OVA-CD8+ LE model revealed hippocampal edema and blood-brain barrier disruption that converted into atrophy until day 40. CD8+ T cells specifically targeted OVA-expressing, SIINFEKL-H-2Kb -positive CA1 neurons and caused segmental apoptotic neurodegeneration, astrogliosis, and microglial activation. At the chronic model stage, mice exhibited spontaneous recurrent seizures and persisting memory deficits, and the sclerotic hippocampus was populated with CD8+ T cells escorted by NK cells. INTERPRETATION These data indicate that a CD8+ T-cell-initiated attack of distinct hippocampal neurons is sufficient to induce LE converting into TLE-HS. Intriguingly, the role of CD8+ T cells exceeds neurotoxic effects and points to their major pathogenic role in TLE following LE. ANN NEUROL 2021;89:666-685.
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Affiliation(s)
- Julika Pitsch
- Section for Translational Epilepsy Research, Department of Neuropathology, University Hospital Bonn, Bonn, Germany
- Department of Epileptology, University Hospital Bonn, Bonn, Germany
| | - Karen M J van Loo
- Section for Translational Epilepsy Research, Department of Neuropathology, University Hospital Bonn, Bonn, Germany
- Department of Epileptology, Neurology, Medical University Rheinisch-Westfälische Technische Hochschule (RWTH) Aachen, Aachen, Germany
| | - Marco Gallus
- Department of Neurology with Institute of Translational Neurology, University of Münster, Münster, Germany
| | - Andre Dik
- Department of Neurology with Institute of Translational Neurology, University of Münster, Münster, Germany
| | - Delara Kamalizade
- Section for Translational Epilepsy Research, Department of Neuropathology, University Hospital Bonn, Bonn, Germany
- Department of Epileptology, University Hospital Bonn, Bonn, Germany
| | | | - Vadym Gnatkovsky
- Department of Epileptology, University Hospital Bonn, Bonn, Germany
| | - Johannes Alexander Müller
- Section for Translational Epilepsy Research, Department of Neuropathology, University Hospital Bonn, Bonn, Germany
| | - Thoralf Opitz
- Institute for Experimental Epileptology and Cognition Research, University Hospital Bonn, Bonn, Germany
| | - Gordon Hicking
- Department of Neurology with Institute of Translational Neurology, University of Münster, Münster, Germany
| | - Venu Narayanan Naik
- Department of Neurology with Institute of Translational Neurology, University of Münster, Münster, Germany
| | - Lydia Wachsmuth
- Department of Clinical Radiology, University of Münster, Münster, Germany
| | - Cornelius Faber
- Department of Clinical Radiology, University of Münster, Münster, Germany
| | - Rainer Surges
- Department of Epileptology, University Hospital Bonn, Bonn, Germany
- Center for Rare Diseases Bonn, University Hospital Bonn, Bonn, Germany
| | - Christian Kurts
- Institute of Experimental Immunology, University Hospital Bonn, Bonn, Germany
| | - Susanne Schoch
- Section for Translational Epilepsy Research, Department of Neuropathology, University Hospital Bonn, Bonn, Germany
- Department of Epileptology, University Hospital Bonn, Bonn, Germany
| | - Nico Melzer
- Department of Neurology with Institute of Translational Neurology, University of Münster, Münster, Germany
| | - Albert J Becker
- Section for Translational Epilepsy Research, Department of Neuropathology, University Hospital Bonn, Bonn, Germany
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8
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Vila Verde D, Zimmer T, Cattalini A, Pereira MF, van Vliet EA, Testa G, Gnatkovsky V, Aronica E, de Curtis M. Seizure activity and brain damage in a model of focal non-convulsive status epilepticus. Neuropathol Appl Neurobiol 2021; 47:679-693. [PMID: 33421166 DOI: 10.1111/nan.12693] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 12/29/2020] [Accepted: 12/30/2020] [Indexed: 11/30/2022]
Abstract
AIMS Focal non-convulsive status epilepticus (FncSE) is a common emergency condition that may present as the first epileptic manifestation. In recent years, it has become increasingly clear that de novo FncSE should be promptly treated to improve post-status outcome. Whether seizure activity occurring during the course of the FncSE contributes to ensuing brain damage has not been demonstrated unequivocally and is here addressed. METHODS We used continuous video-EEG monitoring to characterise an acute experimental FncSE model induced by unilateral intrahippocampal injection of kainic acid (KA) in guinea pigs. Immunohistochemistry and mRNA expression analysis were utilised to detect and quantify brain injury, 3-days and 1-month after FncSE. RESULTS Seizure activity occurring during the course of FncSE involved both hippocampi equally. Neuronal loss, blood-brain barrier permeability changes, gliosis and up-regulation of inflammation, activity-induced and astrocyte-specific genes were observed in the KA-injected hippocampus. Diazepam treatment reduced FncSE duration and KA-induced neuropathological damage. In the contralateral hippocampus, transient and possibly reversible gliosis with increase of aquaporin-4 and Kir4.1 genes were observed 3 days post-KA. No tissue injury and gene expression changes were found 1-month after FncSE. CONCLUSIONS In our model, focal seizures occurring during FncSE worsen ipsilateral KA-induced tissue damage. FncSE only transiently activated glia in regions remote from KA-injection, suggesting that seizure activity during FncSE without local pathogenic co-factors does not promote long-lasting detrimental changes in the brain. These findings demonstrate that in our experimental model, brain damage remains circumscribed to the area where the primary cause (KA) of the FncSE acts. Our study emphasises the need to use antiepileptic drugs to contain local damage induced by focal seizures that occur during FncSE.
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Affiliation(s)
- Diogo Vila Verde
- Epilepsy Unit, Fondazione Istituto Neurologico Carlo Besta, Milan, Italy
| | - Till Zimmer
- Department of (Neuro) Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Amsterdam, The Netherlands
| | | | - Marlene F Pereira
- Department of Oncology and Hematooncology, University of Milan, Milan, Italy.,Laboratory of Stem Cell Epigenetics, IEO, European Institute of Oncology, IRCCS, Milan, Italy
| | - Erwin A van Vliet
- Department of (Neuro) Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Amsterdam, The Netherlands.,Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, Amsterdam, The Netherlands
| | - Giuseppe Testa
- Department of Oncology and Hematooncology, University of Milan, Milan, Italy.,Laboratory of Stem Cell Epigenetics, IEO, European Institute of Oncology, IRCCS, Milan, Italy
| | - Vadym Gnatkovsky
- Epilepsy Unit, Fondazione Istituto Neurologico Carlo Besta, Milan, Italy
| | - Eleonora Aronica
- Department of (Neuro) Pathology, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Amsterdam, The Netherlands.,Stichting Epilepsie Instellingen Nederland (SEIN), Heemstede, The Netherlands
| | - Marco de Curtis
- Epilepsy Unit, Fondazione Istituto Neurologico Carlo Besta, Milan, Italy
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9
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Gnatkovsky V, Cattalini A, Antonini A, Spreafico L, Saini M, Noè F, Alessi C, Librizzi L, Uva L, Marras CE, de Curtis M, Ferrari S. Recording Electrical Brain Activity with Novel Stretchable Electrodes Based on Supersonic Cluster Beam Implantation Nanotechnology on Conformable Polymers. Int J Nanomedicine 2020; 14:10079-10089. [PMID: 31920304 PMCID: PMC6935312 DOI: 10.2147/ijn.s224243] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Accepted: 09/25/2019] [Indexed: 11/23/2022] Open
Abstract
Background Multielectrodes are implanted in central and peripheral nervous systems for rehabilitation and diagnostic purposes. The physical resistance of intracranial devices to mechanical stress is critical and fractures or electrode displacement may occur. We describe here a new recording device with stretchable properties based on Supersonic Cluster Beam Implantation (SCBI) technology with high mechanical adaptability to displacement and movement. Results The capability of SCBI-based multichannel electrodes to record brain electrical activity was compared to glass/silicon microelectrodes in acute in vitro experiments on the isolated guinea pig brain preparation. Field potentials and power frequency analysis demonstrated equal recording features for SCBI and standard electrodes. Chronic in vivo epidural implantation of the SCBI electrodes confirmed excellent long-term recording properties in comparison to standard EEG metal electrodes. Tissue biocompatibility was demonstrated by neuropathological evaluation of the brain tissue 2 months after the implantation of the devices in the subarachnoid space. Conclusion We confirm the biocompatibility of novel SCBI-based stretchable electrode devices and demonstrate their suitability for recording electrical brain activity in pre-clinical settings.
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Affiliation(s)
- Vadym Gnatkovsky
- Unit of Epileptology, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy
| | - Alessandro Cattalini
- Unit of Epileptology, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy
| | | | | | | | - Francesco Noè
- Unit of Epileptology, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy
| | - Camilla Alessi
- Unit of Epileptology, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy
| | - Laura Librizzi
- Unit of Epileptology, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy
| | - Laura Uva
- Unit of Epileptology, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy
| | - Carlo Efisio Marras
- Neurosurgery Unit, Department of Neuroscience and Neurorehabilitation, IRCCS Bambino Gesù Children's Hospital, Roma, Italy
| | - Marco de Curtis
- Unit of Epileptology, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy
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10
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Di Giacomo R, Gnatkovsky V, Deleo F, Amorim I, Didato G, Pastori C, Marras CE, Villani F, de Curtis M. How deep do we have to go? Recurrent episodes of aura continua with psychic symptoms may be misdiagnosed without intracranial recordings. Clin Neurophysiol 2019; 131:580-582. [PMID: 31831266 DOI: 10.1016/j.clinph.2019.11.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Revised: 11/08/2019] [Accepted: 11/13/2019] [Indexed: 11/16/2022]
Affiliation(s)
- Roberta Di Giacomo
- Epilepsy Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Via Celoria 11, 20133 Milan, Italy.
| | - Vadym Gnatkovsky
- Epilepsy Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Via Celoria 11, 20133 Milan, Italy.
| | - Francesco Deleo
- Epilepsy Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Via Celoria 11, 20133 Milan, Italy.
| | - Isabel Amorim
- Neurology Department, Hospital de Santa Maria-CHULN, Lisbon, Portugal
| | - Giuseppe Didato
- Epilepsy Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Via Celoria 11, 20133 Milan, Italy.
| | - Chiara Pastori
- Epilepsy Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Via Celoria 11, 20133 Milan, Italy.
| | - Carlo Efisio Marras
- Neurosurgery Unit, Department of Neuroscience and Neurorehabilitation, IRCCS Bambino Gesù Children's Hospital, Rome, Italy.
| | - Flavio Villani
- Epilepsy Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Via Celoria 11, 20133 Milan, Italy; Division of Clinical Neurophysiology, Policlinico IRCCS San Martino, Largo Benzi 10, 16132 Genova, Italy.
| | - Marco de Curtis
- Epilepsy Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Via Celoria 11, 20133 Milan, Italy.
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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] [What about the content of this article? (0)] [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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Salgueiro-Pereira AR, Duprat F, Pousinha PA, Loucif A, Douchamps V, Regondi C, Ayrault M, Eugie M, Stunault MI, Escayg A, Goutagny R, Gnatkovsky V, Frassoni C, Marie H, Bethus I, Mantegazza M. A two-hit story: Seizures and genetic mutation interaction sets phenotype severity in SCN1A epilepsies. Neurobiol Dis 2019; 125:31-44. [DOI: 10.1016/j.nbd.2019.01.006] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 12/14/2018] [Accepted: 01/14/2019] [Indexed: 01/07/2023] Open
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13
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Pelliccia V, Villani F, Gozzo F, Gnatkovsky V, Cardinale F, Tassi L. Musicogenic epilepsy: A Stereo-electroencephalography study. Cortex 2019; 120:582-587. [PMID: 30837152 DOI: 10.1016/j.cortex.2019.02.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 12/02/2018] [Accepted: 02/05/2019] [Indexed: 11/30/2022]
Abstract
Musicogenic epilepsy is rare focal epilepsy in which seizures are triggered by music. Both spontaneous and reflexes seizures may occur. To date there are limited data about this epilepsy, particularly about its etiopathogenesis. We report the clinical, neurophysiological and imaging data about musicogenic epilepsy in a patient who underwent Stereo-electroencephalography (SEEG) study. A 27 year-old right-handed woman suffering from drug-resistant epilepsy since the age of 17 years, was evaluated for surgery. She had weekly seizures characterized by an unpleasant ascending gastric sensation, tachycardia, occasionally late oro-alimentary automatisms, déjà-vu and vomiting. Only during longer seizures a partial loss of awareness was reported. Interestingly, familiar songs triggered seizures. Rarely, she had spontaneous seizures with the same features. The ictal EEG onset appeared to be right temporal, but there was seizure propagation to suprasylvian areas. Brain MRI was negative. A SEEG implantation was performed to study the right temporo-perisylvian regions. SEEG data clearly indicated the antero-mesial temporal regions as origin of the seizures, without any spread to other close or distant cortical areas. Right temporal antero-mesial resection was performed 24 months ago and the patient is seizure-free since surgery. Neuropathology was uninformative. SEEG data highlighted the hypothesis regarding a temporo-mesial emotional-mnesic network triggered by particular music with an affective component for the patient. The primary auditory cortex and lateral mid-posterior temporal and extratemporal cortices were not involved. Different triggers as mentally singing and hearing the music can induce seizure as well as electrical stimulation in the mesial temporal structures.
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Affiliation(s)
| | - Flavio Villani
- Epilepsy Unit, Fondazione IRCCS, Istituto Neurologico C. Besta, Milano, Italy
| | - Francesca Gozzo
- C. Munari Epilepsy Surgery Centre, Ospedale Niguarda, Milano, Italy
| | - Vadym Gnatkovsky
- Epilepsy Unit, Fondazione IRCCS, Istituto Neurologico C. Besta, Milano, Italy
| | | | - Laura Tassi
- C. Munari Epilepsy Surgery Centre, Ospedale Niguarda, Milano, Italy.
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14
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Gnatkovsky V, Pelliccia V, de Curtis M, Tassi L. Two main focal seizure patterns revealed by intracerebral electroencephalographic biomarker analysis. Epilepsia 2018; 60:96-106. [DOI: 10.1111/epi.14610] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 10/08/2018] [Accepted: 10/29/2018] [Indexed: 02/06/2023]
Affiliation(s)
- Vadym Gnatkovsky
- Epilepsy Unit; Institute of Cure, Recovery, and Scientific Research (IRCCS) Foundation Carlo Besta Neurological Institute; Milan Italy
| | | | - Marco de Curtis
- Epilepsy Unit; Institute of Cure, Recovery, and Scientific Research (IRCCS) Foundation Carlo Besta Neurological Institute; Milan Italy
| | - Laura Tassi
- Claudio Munari Epilepsy Surgery Center; Niguarda Hospital; Milan Italy
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15
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Pitsch J, Kuehn JC, Gnatkovsky V, Müller JA, van Loo KMJ, de Curtis M, Vatter H, Schoch S, Elger CE, Becker AJ. Anti-epileptogenic and Anti-convulsive Effects of Fingolimod in Experimental Temporal Lobe Epilepsy. Mol Neurobiol 2018; 56:1825-1840. [PMID: 29934763 DOI: 10.1007/s12035-018-1181-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 06/06/2018] [Indexed: 12/11/2022]
Abstract
Temporal lobe epilepsy (TLE) represents a devastating neurological condition, in which approximately 4/5 of patients remain refractory for anti-convulsive drugs. Epilepsy surgery biopsies often reveal the damage pattern of "hippocampal sclerosis" (HS) characterized not only by neuronal loss but also pronounced astrogliosis and inflammatory changes. Since TLE shares distinct pathogenetic aspects with multiple sclerosis (MS), we have here scrutinized therapeutic effects in experimental TLE of the immunmodulator fingolimod, which is established in MS therapy. Fingolimod targets sphingosine-phosphate receptors (S1PRs). mRNAs of fingolimod target S1PRs were augmented in two experimental post status epilepticus (SE) TLE mouse models (suprahippocampal kainate/pilocarpine). SE frequently induces chronic recurrent seizures after an extended latency referred to as epileptogenesis. Transient fingolimod treatment of mice during epileptogenesis after suprahippocampal kainate-induced SE revealed substantial reduction of chronic seizure activity despite lacking acute attenuation of SE itself. Intriguingly, fingolimod exerted robust anti-convulsive activity in kainate-induced SE mice treated in the chronic TLE stage and had neuroprotective and anti-gliotic effects and reduced cytotoxic T cell infiltrates. Finally, the expression profile of fingolimod target-S1PRs in human hippocampal biopsy tissue of pharmacoresistant TLE patients undergoing epilepsy surgery for seizure relief suggests repurposing of fingolimod as novel therapeutic perspective in focal epilepsies.
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Affiliation(s)
- Julika Pitsch
- Section for Translational Epilepsy Research, Department of Neuropathology, University of Bonn Medical Center, Sigmund-Freud-Str. 25, 53105, Bonn, Germany.
| | - Julia C Kuehn
- Section for Translational Epilepsy Research, Department of Neuropathology, University of Bonn Medical Center, Sigmund-Freud-Str. 25, 53105, Bonn, Germany
| | - Vadym Gnatkovsky
- Unit of Epileptology and Experimental Neurophysiology, Fondazione Istituto Neurologico Carlo Besta, 20133, Milan, Italy
| | - Johannes Alexander Müller
- Section for Translational Epilepsy Research, Department of Neuropathology, University of Bonn Medical Center, Sigmund-Freud-Str. 25, 53105, Bonn, Germany
| | - Karen M J van Loo
- Section for Translational Epilepsy Research, Department of Neuropathology, University of Bonn Medical Center, Sigmund-Freud-Str. 25, 53105, Bonn, Germany
| | - Marco de Curtis
- Unit of Epileptology and Experimental Neurophysiology, Fondazione Istituto Neurologico Carlo Besta, 20133, Milan, Italy
| | - Hartmut Vatter
- Clinic for Neurosurgery, University of Bonn Medical Center, 53105, Bonn, Germany
| | - Susanne Schoch
- Section for Translational Epilepsy Research, Department of Neuropathology, University of Bonn Medical Center, Sigmund-Freud-Str. 25, 53105, Bonn, Germany.,Clinic for Epileptology, University of Bonn Medical Center, 53105, Bonn, Germany
| | - Christian E Elger
- Clinic for Epileptology, University of Bonn Medical Center, 53105, Bonn, Germany
| | - Albert J Becker
- Section for Translational Epilepsy Research, Department of Neuropathology, University of Bonn Medical Center, Sigmund-Freud-Str. 25, 53105, Bonn, Germany
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16
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Moyer JT, Gnatkovsky V, Ono T, Otáhal J, Wagenaar J, Stacey WC, Noebels J, Ikeda A, Staley K, de Curtis M, Litt B, Galanopoulou AS. Standards for data acquisition and software-based analysis of in vivo electroencephalography recordings from animals. A TASK1-WG5 report of the AES/ILAE Translational Task Force of the ILAE. Epilepsia 2017; 58 Suppl 4:53-67. [PMID: 29105070 DOI: 10.1111/epi.13909] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/25/2016] [Indexed: 01/12/2023]
Abstract
Electroencephalography (EEG)-the direct recording of the electrical activity of populations of neurons-is a tremendously important tool for diagnosing, treating, and researching epilepsy. Although standard procedures for recording and analyzing human EEG exist and are broadly accepted, there are no such standards for research in animal models of seizures and epilepsy-recording montages, acquisition systems, and processing algorithms may differ substantially among investigators and laboratories. The lack of standard procedures for acquiring and analyzing EEG from animal models of epilepsy hinders the interpretation of experimental results and reduces the ability of the scientific community to efficiently translate new experimental findings into clinical practice. Accordingly, the intention of this report is twofold: (1) to review current techniques for the collection and software-based analysis of neural field recordings in animal models of epilepsy, and (2) to offer pertinent standards and reporting guidelines for this research. Specifically, we review current techniques for signal acquisition, signal conditioning, signal processing, data storage, and data sharing, and include applicable recommendations to standardize collection and reporting. We close with a discussion of challenges and future opportunities, and include a supplemental report of currently available acquisition systems and analysis tools. This work represents a collaboration on behalf of the American Epilepsy Society/International League Against Epilepsy (AES/ILAE) Translational Task Force (TASK1-Workgroup 5), and is part of a larger effort to harmonize video-EEG interpretation and analysis methods across studies using in vivo and in vitro seizure and epilepsy models.
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Affiliation(s)
- Jason T Moyer
- Department of Neurology, Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania, U.S.A
| | - Vadym Gnatkovsky
- IRCCS Foundation, Epileptology and Experimental Neurophysiology Unit, Carlo Besta Neurological Institute, Milan, Italy
| | - Tomonori Ono
- Department of Neurosurgery, National Nagasaki Medical Center, Omura, Nagasaki, Japan
| | - Jakub Otáhal
- Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Joost Wagenaar
- Department of Neurology, Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania, U.S.A
| | - William C Stacey
- Departments of Neurology and Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, U.S.A
| | - Jeffrey Noebels
- Department of Neurology, Baylor College of Medicine, Houston, Texas, U.S.A
| | - Akio Ikeda
- Department of Epilepsy, Movement Disorders and Physiology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Kevin Staley
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, U.S.A
| | - Marco de Curtis
- IRCCS Foundation, Epileptology and Experimental Neurophysiology Unit, Carlo Besta Neurological Institute, Milan, Italy
| | - Brian Litt
- Departments of Neurology, Neurosurgery, and Bioengineering, Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania, U.S.A
| | - Aristea S Galanopoulou
- Laboratory of Developmental Epilepsy, Saul R. Korey Department of Neurology, Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, U.S.A
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Rossini L, Garbelli R, Gnatkovsky V, Didato G, Villani F, Spreafico R, Deleo F, Lo Russo G, Tringali G, Gozzo F, Tassi L, de Curtis M. Seizure activity per se does not induce tissue damage markers in human neocortical focal epilepsy. Ann Neurol 2017; 82:331-341. [PMID: 28749594 DOI: 10.1002/ana.25005] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 07/10/2017] [Accepted: 07/17/2017] [Indexed: 12/31/2022]
Abstract
OBJECTIVE The contribution of recurring seizures to the progression of epileptogenesis is debated. Seizure-induced brain damage is not conclusively demonstrated either in humans or in animal models of epilepsy. We evaluated the expression of brain injury biomarkers on postsurgical brain tissue obtained from 20 patients with frequent seizures and a long history of drug-resistant focal epilepsy. METHODS The expression patterns of specific glial, neuronal, and inflammatory molecules were evaluated by immunohistochemistry in the core of type II focal cortical dysplasias (FCD-II), at the FCD boundary (perilesion), and in the adjacent normal-appearing area included in the epileptogenic region. We also analyzed surgical specimens from cryptogenic patients not presenting structural alterations at imaging. RESULTS Astroglial and microglial activation, reduced neuronal density, perivascular CD3-positive T-lymphocyte clustering, and fibrinogen extravasation were demonstrated in the core of FCD-II lesions. No pathological immunoreactivity was observed outside the FCD-II or in cryptogenetic specimens, where the occurrence of interictal and ictal epileptiform activity was confirmed by either stereo-electroencephalography or intraoperative electrocorticography. INTERPRETATION Recurrent seizures do not induce the expression of brain damage markers in nonlesional epileptogenic cortex studied in postsurgical tissue from cryptogenic and FCD patients. This evidence argues against the hypothesis that epileptiform activity per se contributes to focal brain injury, at least in the neocortical epilepsies considered here. Ann Neurol 2017;82:331-341.
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Affiliation(s)
- Laura Rossini
- Epilepsy Unit, C. Besta Neurological Institute Foundation
| | - Rita Garbelli
- Epilepsy Unit, C. Besta Neurological Institute Foundation
| | | | | | - Flavio Villani
- Epilepsy Unit, C. Besta Neurological Institute Foundation
| | | | | | | | - Giovanni Tringali
- Neurosurgery Unit, C. Besta Neurological Institute Foundation, Milan, Italy
| | | | - Laura Tassi
- C. Munari Epilepsy Surgery Center, Niguarda Hospital
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Jozwiak S, Becker A, Cepeda C, Engel J, Gnatkovsky V, Huberfeld G, Kaya M, Kobow K, Simonato M, Loeb JA. WONOEP appraisal: Development of epilepsy biomarkers-What we can learn from our patients? Epilepsia 2017; 58:951-961. [PMID: 28387933 PMCID: PMC5806696 DOI: 10.1111/epi.13728] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/20/2017] [Indexed: 12/13/2022]
Abstract
OBJECTIVE Current medications for patients with epilepsy work in only two of three patients. For those medications that do work, they only suppress seizures. They treat the symptoms, but do not modify the underlying disease, forcing patients to take these drugs with significant side effects, often for the rest of their lives. A major limitation in our ability to advance new therapeutics that permanently prevent, reduce the frequency of, or cure epilepsy comes from a lack of understanding of the disease coupled with a lack of reliable biomarkers that can predict who has or who will get epilepsy. METHODS The main goal of this report is to present a number of approaches for identifying reliable biomarkers from observing patients with brain disorders that have a high probability of producing epilepsy. RESULTS A given biomarker, or more likely a profile of biomarkers, will have both a quantity and a time course during epileptogenesis that can be used to predict who will get the disease, to confirm epilepsy as a diagnosis, to identify coexisting pathologies, and to monitor the course of treatments. SIGNIFICANCE Additional studies in patients and animal models could identify common and clinically valuable biomarkers to successfully translate animal studies into new and effective clinical trials.
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Affiliation(s)
- Sergiusz Jozwiak
- Department of Child Neurology, Medical University of Warsaw, Poland
- Department of Child Neurology, The Children’s Memorial Health Institute, Warsaw, Poland
| | - Albert Becker
- Section for Translational Epilepsy Research, Department of Neuropathology, University of Bonn Medical Center, Bonn, Germany
| | - Carlos Cepeda
- IDDRC, Semel Institute for Neuroscience & Human Behavior, University of California Los Angeles, Los Angeles, CA, USA
| | - Jerome Engel
- Departments of Neurology, Neurobiology, and Psychiatry & Biobehavioral Sciences and the Brain Research Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA
| | - Vadym Gnatkovsky
- Unit of Epilepsy and Experimental Neurophysiology, Fondazione Istituto Neurologico Carlo Besta, Milan, Italy
| | - Gilles Huberfeld
- Sorbonne and UPMC University, AP-HP, Department of Neurophysiology, UPMC and La Pitié-Salpêtrière Hospital, Paris, France
- INSERM U1129, Paris Descartes University, PRES Sorbonne Paris, Cité, Paris, CEA, France
| | - Mehmet Kaya
- Department of Physiology, Koc University School of Medicine, Rumelifeneri Yolu, Sariver, Istanbul, Turkey
| | - Katja Kobow
- Department of Neuropathology, University Hospital Erlangen, Erlangen, Germany
| | - Michele Simonato
- Department of Medical Sciences, University of Ferrara and Division of Neuroscience, University Vita-Salute San Raffaele, Milan, Italy
| | - Jeffrey A. Loeb
- Department of Neurology and Rehabilitation, The University of Illinois at Chicago, Chicago, IL
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Abstract
Traditionally, it is considered that neuronal synchronization in epilepsy is caused by a chain reaction of synaptic excitation. However, it has been shown that synchronous epileptiform activity may also arise without synaptic transmission. In order to investigate the respective roles of synaptic interactions and nonsynaptic mechanisms in seizure transitions, we developed a computational model of hippocampal cells, involving the extracellular space, realistic dynamics of [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] ions, glial uptake and extracellular diffusion mechanisms. We show that the network behavior with fixed ionic concentrations may be quite different from the neurons' behavior when more detailed modeling of ionic dynamics is included. In particular, we show that in the extended model strong discharge of inhibitory interneurons may result in long lasting accumulation of extracellular [Formula: see text], which sustains the depolarization of the principal cells and causes their pathological discharges. This effect is not present in a reduced, purely synaptic network. These results point to the importance of nonsynaptic mechanisms in the transition to seizure.
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Affiliation(s)
- Damiano Gentiletti
- 1 Department of Biomedical Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, Warsaw, Poland
| | - Piotr Suffczynski
- 1 Department of Biomedical Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, Warsaw, Poland
| | - Vadym Gnatkovsky
- 2 Unit of Epileptology and Experimental Neurophysiology, Fondazione IRCCS Istituto Neurologico Carlo Besta, Via Giovanni Celoria 11, Milan, Italy
| | - Marco de Curtis
- 2 Unit of Epileptology and Experimental Neurophysiology, Fondazione IRCCS Istituto Neurologico Carlo Besta, Via Giovanni Celoria 11, Milan, Italy
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20
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Pitsch J, Becker AJ, Schoch S, Müller JA, de Curtis M, Gnatkovsky V. Circadian clustering of spontaneous epileptic seizures emerges after pilocarpine-induced status epilepticus. Epilepsia 2017; 58:1159-1171. [DOI: 10.1111/epi.13795] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/12/2017] [Indexed: 01/02/2023]
Affiliation(s)
- Julika Pitsch
- Section for Translational Epilepsy Research; Department of Neuropathology; University of Bonn; Bonn Germany
| | - Albert J. Becker
- Section for Translational Epilepsy Research; Department of Neuropathology; University of Bonn; Bonn Germany
| | - Susanne Schoch
- Section for Translational Epilepsy Research; Department of Neuropathology; University of Bonn; Bonn Germany
| | - Johannes Alexander Müller
- Section for Translational Epilepsy Research; Department of Neuropathology; University of Bonn; Bonn Germany
| | - Marco de Curtis
- Unit of Epileptology and Experimental Neurophysiology; Fondazione Istituto Neurologico Carlo Besta; Milan Italy
| | - Vadym Gnatkovsky
- Unit of Epileptology and Experimental Neurophysiology; Fondazione Istituto Neurologico Carlo Besta; Milan Italy
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21
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Pastori C, Francione S, Pelle F, de Curtis M, Gnatkovsky V. Fluency tasks generate beta-gamma activity in language-related cortical areas of patients during stereo-EEG monitoring. Brain Lang 2016; 163:50-56. [PMID: 27684988 DOI: 10.1016/j.bandl.2016.09.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Revised: 09/07/2016] [Accepted: 09/12/2016] [Indexed: 06/06/2023]
Abstract
A quantitative method was developed to map cortical areas responsive to cognitive tasks during intracerebral stereo-EEG recording sessions in drug-resistant patients candidate for epilepsy surgery. Frequency power changes were evaluated with a computer-assisted analysis in 7 patients during phonemic fluency tasks. All patients were right-handed and were explored with depth electrodes in the dominant frontal lobe. We demonstrate that fluency tasks enhance beta-gamma frequencies and reduce background activities in language network regions of the dominant hemisphere. Non-reproducible changes were observed in other explored brain areas during cognitive tests execution.
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Affiliation(s)
- Chiara Pastori
- Unit of Epileptology and Experimental Neurophysiology, Fondazione Istituto Neurologico Carlo Besta, Milano, Italy
| | - Stefano Francione
- Claudio Munari Epilepsy Surgery Center, Ospedale Niguarda, Milano, Italy
| | - Federica Pelle
- Claudio Munari Epilepsy Surgery Center, Ospedale Niguarda, Milano, Italy
| | - Marco de Curtis
- Unit of Epileptology and Experimental Neurophysiology, Fondazione Istituto Neurologico Carlo Besta, Milano, Italy
| | - Vadym Gnatkovsky
- Unit of Epileptology and Experimental Neurophysiology, Fondazione Istituto Neurologico Carlo Besta, Milano, Italy.
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Avoli M, de Curtis M, Gnatkovsky V, Gotman J, Köhling R, Lévesque M, Manseau F, Shiri Z, Williams S. Specific imbalance of excitatory/inhibitory signaling establishes seizure onset pattern in temporal lobe epilepsy. J Neurophysiol 2016; 115:3229-37. [PMID: 27075542 DOI: 10.1152/jn.01128.2015] [Citation(s) in RCA: 102] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 04/06/2016] [Indexed: 11/22/2022] Open
Abstract
Low-voltage fast (LVF) and hypersynchronous (HYP) patterns are the seizure-onset patterns most frequently observed in intracranial EEG recordings from mesial temporal lobe epilepsy (MTLE) patients. Both patterns also occur in models of MTLE in vivo and in vitro, and these studies have highlighted the predominant involvement of distinct neuronal network/neurotransmitter receptor signaling in each of them. First, LVF-onset seizures in epileptic rodents can originate from several limbic structures, frequently spread, and are associated with high-frequency oscillations in the ripple band (80-200 Hz), whereas HYP onset seizures initiate in the hippocampus and tend to remain focal with predominant fast ripples (250-500 Hz). Second, in vitro intracellular recordings from principal cells in limbic areas indicate that pharmacologically induced seizure-like discharges with LVF onset are initiated by a synchronous inhibitory event or by a hyperpolarizing inhibitory postsynaptic potential barrage; in contrast, HYP onset is associated with a progressive impairment of inhibition and concomitant unrestrained enhancement of excitation. Finally, in vitro optogenetic experiments show that, under comparable experimental conditions (i.e., 4-aminopyridine application), the initiation of LVF- or HYP-onset seizures depends on the preponderant involvement of interneuronal or principal cell networks, respectively. Overall, these data may provide insight to delineate better therapeutic targets in the treatment of patients presenting with MTLE and, perhaps, with other epileptic disorders as well.
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Affiliation(s)
- Massimo Avoli
- Montreal Neurological Institute and Departments of Neurology & Neurosurgery and of Physiology, McGill University, Montréal, Québec, Canada; Facoltà di Medicina e Odontoiatria, Sapienza Università di Roma, Rome, Italy;
| | - Marco de Curtis
- Epilepsy Unit, Fondazione Istituto Neurologico Carlo Besta, Milan, Italy
| | - Vadym Gnatkovsky
- Epilepsy Unit, Fondazione Istituto Neurologico Carlo Besta, Milan, Italy
| | - Jean Gotman
- Montreal Neurological Institute and Departments of Neurology & Neurosurgery and of Physiology, McGill University, Montréal, Québec, Canada
| | - Rüdiger Köhling
- Oscar-Langendorff-Institute of Physiology, Rostock University Medical Center, Rostock, Germany; and
| | - Maxime Lévesque
- Montreal Neurological Institute and Departments of Neurology & Neurosurgery and of Physiology, McGill University, Montréal, Québec, Canada
| | - Frédéric Manseau
- Douglas Mental Health University Institute, McGill University, Montréal, Québec, Canada
| | - Zahra Shiri
- Montreal Neurological Institute and Departments of Neurology & Neurosurgery and of Physiology, McGill University, Montréal, Québec, Canada
| | - Sylvain Williams
- Douglas Mental Health University Institute, McGill University, Montréal, Québec, Canada
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Pennacchio P, Noé F, Gnatkovsky V, Moroni RF, Zucca I, Regondi MC, Inverardi F, de Curtis M, Frassoni C. Increased pCREB expression and the spontaneous epileptiform activity in a BCNU-treated rat model of cortical dysplasia. Epilepsia 2015; 56:1343-54. [DOI: 10.1111/epi.13070] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/05/2015] [Indexed: 11/29/2022]
Affiliation(s)
- Paolo Pennacchio
- Clinical Epileptology and Experimental Neurophysiology Unit; IRCCS Foundation Neurological Institute “C. Besta”; Milano Italy
| | - Francesco Noé
- Clinical Epileptology and Experimental Neurophysiology Unit; IRCCS Foundation Neurological Institute “C. Besta”; Milano Italy
| | - Vadym Gnatkovsky
- Clinical Epileptology and Experimental Neurophysiology Unit; IRCCS Foundation Neurological Institute “C. Besta”; Milano Italy
| | - Ramona Frida Moroni
- Clinical Epileptology and Experimental Neurophysiology Unit; IRCCS Foundation Neurological Institute “C. Besta”; Milano Italy
| | - Ileana Zucca
- Scientific Department; IRCCS Foundation Neurological Institute “C. Besta”; Milano Italy
| | - Maria Cristina Regondi
- Clinical Epileptology and Experimental Neurophysiology Unit; IRCCS Foundation Neurological Institute “C. Besta”; Milano Italy
| | - Francesca Inverardi
- Clinical Epileptology and Experimental Neurophysiology Unit; IRCCS Foundation Neurological Institute “C. Besta”; Milano Italy
| | - Marco de Curtis
- Clinical Epileptology and Experimental Neurophysiology Unit; IRCCS Foundation Neurological Institute “C. Besta”; Milano Italy
| | - Carolina Frassoni
- Clinical Epileptology and Experimental Neurophysiology Unit; IRCCS Foundation Neurological Institute “C. Besta”; Milano Italy
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Bellistri E, Sartori I, Pelliccia V, Francione S, Cardinale F, de Curtis M, Gnatkovsky V. Fast Activity Evoked by Intracranial 50 Hz Electrical Stimulation as a Marker of the Epileptogenic Zone. Int J Neural Syst 2015; 25:1550022. [PMID: 26022387 DOI: 10.1142/s0129065715500227] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Epilepsy is a disease characterized by aberrant connections between brain areas. The altered activity patterns generated by epileptic networks can be analyzed with intracerebral electrodes during pre-surgical stereo-electroencephalographic (EEG) monitoring in patients candidate to epilepsy surgery. The responses to high frequency stimulation (HFS) at 50 Hz performed for diagnostic purposes during SEEG were analyzed with a new algorithm, to evaluate signal parameters that are masked to visual inspection and to define the boundaries of the epileptogenic network. The analysis was focused on 60-80 Hz activity that represented the largest frequency component evoked by HFS. The distribution of HFS-evoked fast activity across all (up to 162) recording contacts allowed to define different clusters of contacts that retrospectively correlated to the epileptogenic zone identified by the clinicians on the basis of traditional visual analysis. The study demonstrates that computer-assisted analysis of HFS-evoked activities may contribute to the definition of the epileptogenic network on intracranial recordings performed in a pre-surgical setting.
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Affiliation(s)
- Elisa Bellistri
- Unit of Epileptology and Experimental Neurophysiology, Fondazione IRCCS, Istituto Neurologico Carlo Besta, 20133 Milano, Italy
| | - Ivana Sartori
- Claudio Munari Epilepsy Surgery Center, Ospedale, Niguarda Ca' Granda, Milano, Italy
| | - Veronica Pelliccia
- Claudio Munari Epilepsy Surgery Center, Ospedale, Niguarda Ca' Granda, Milano, Italy
| | - Stefano Francione
- Claudio Munari Epilepsy Surgery Center, Ospedale, Niguarda Ca' Granda, Milano, Italy
| | - Francesco Cardinale
- Claudio Munari Epilepsy Surgery Center, Ospedale, Niguarda Ca' Granda, Milano, Italy
| | - Marco de Curtis
- Unit of Epileptology and Experimental Neurophysiology, Fondazione IRCCS, Istituto Neurologico Carlo Besta, 20133 Milano, Italy
| | - Vadym Gnatkovsky
- Unit of Epileptology and Experimental Neurophysiology, Fondazione IRCCS, Istituto Neurologico Carlo Besta, 20133 Milano, Italy
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25
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Arcieri S, Zanotta N, Gnatkovsky V, Avantaggiato P, Formica F, Epifanio R, Angelini L, Strazzer S, Zucca C. Paroxysmal phenomena in severe disabled children with refractory seizures. From clinical to long-video-EEG processing data to re-examine suspect events. Res Dev Disabil 2015; 36C:125-133. [PMID: 25462473 DOI: 10.1016/j.ridd.2014.08.040] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Revised: 08/18/2014] [Accepted: 08/20/2014] [Indexed: 06/04/2023]
Abstract
To provide an estimate of the occurrence of misdiagnosis in paroxysmal events in institutionalized children with severe disabilities and refractory epilepsy. A multi-step diagnostic survey, from observational to long-term video-EEG monitoring was performed in 46 severe disabled children. Multirater Kappa statistic was used to assess agreement between investigators and to individualize children who remained with dubious events. Subsequently, prolonged EEG-video monitoring analysis was performed in selected children to define phenomena due to seizures. A total of 128 video records were performed, 64 routine video-EEG and 27 long-monitoring video-EEG data were screened for detailed analysis. Thirty (21 female, 9 male) children (65%) with dubious seizures were identified by video records (concordance K=0.63). Of these, in 18 children (39%) seizures were excluded by routine video-EEG monitoring (K=0.86). Twelve children (26%) required accurate investigations with long-term video-EEG. In 5 children (11%), 3 symptomatic and 2 cryptogenic, very short and subtle seizures were confirmed by investigators concordance (K=0.83). Distinguishing paroxysmal phenomena is a challenge in children with severe disabilities; its most remarkable consequence is inappropriate pharmacological treatment and social costs. Our data suggest that the frequency of misdiagnosis could have been underestimated. The clinicians who manage children with severe disabilities and refractory epilepsy must remain alert to risk of an incorrect treatment.
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Affiliation(s)
- Salvatore Arcieri
- Unit of Clinical Neurophysiology, Scientific Institute IRCCS E. Medea, Via Don Luigi Monza 20/A, 23842 Bosisio Parini, LC, Italy; Diurnal Care Centre, Department of Congenital and Acquired Severe Brain Damage, Unit of Neuropsychiatry, Scientific Institute IRCCS Don C. Gnocchi, Via privata d'Adda 2, 22044 Inverigo, CO, Italy.
| | - Nicoletta Zanotta
- Unit of Clinical Neurophysiology, Scientific Institute IRCCS E. Medea, Via Don Luigi Monza 20/A, 23842 Bosisio Parini, LC, Italy
| | - Vadym Gnatkovsky
- Unit of Epileptology and Experimental Neurophysiology, The Foundation of the Carlo Besta Neurological Institute, Milano, Italy
| | - Paolo Avantaggiato
- Acquired Brain Injury Unit, Scientific Institute, IRCCS E. Medea, Via Don Luigi Monza 20/A, 23842 Bosisio Parini, LC, Italy
| | - Francesca Formica
- Acquired Brain Injury Unit, Scientific Institute, IRCCS E. Medea, Via Don Luigi Monza 20/A, 23842 Bosisio Parini, LC, Italy
| | - Roberta Epifanio
- Unit of Clinical Neurophysiology, Scientific Institute IRCCS E. Medea, Via Don Luigi Monza 20/A, 23842 Bosisio Parini, LC, Italy
| | - Lucia Angelini
- Diurnal Care Centre, Department of Congenital and Acquired Severe Brain Damage, Unit of Neuropsychiatry, Scientific Institute IRCCS Don C. Gnocchi, Via privata d'Adda 2, 22044 Inverigo, CO, Italy
| | - Sandra Strazzer
- Acquired Brain Injury Unit, Scientific Institute, IRCCS E. Medea, Via Don Luigi Monza 20/A, 23842 Bosisio Parini, LC, Italy
| | - Claudio Zucca
- Unit of Clinical Neurophysiology, Scientific Institute IRCCS E. Medea, Via Don Luigi Monza 20/A, 23842 Bosisio Parini, LC, Italy
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26
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Arcieri S, Velotti R, Noè F, Carriero G, Cattalini A, Galbardi B, Gnatkovsky V, de Curtis M. Variable electrobehavioral patterns during focal nonconvulsive status epilepticus induced by unilateral intrahippocampal injection of kainic acid. Epilepsia 2014; 55:1978-85. [DOI: 10.1111/epi.12850] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/23/2014] [Indexed: 11/28/2022]
Affiliation(s)
- Salvatore Arcieri
- Unit of Epileptology and Experimental Neurophysiology; Fondazione Neurological Institute Carlo Besta; Milan Italy
- Unit of Clinical Neurophysiology; Scientific Institute IRCCS E. Medea; Bosisio Parini (LC) Italy
| | - Rosa Velotti
- Unit of Epileptology and Experimental Neurophysiology; Fondazione Neurological Institute Carlo Besta; Milan Italy
| | - Francesco Noè
- Unit of Epileptology and Experimental Neurophysiology; Fondazione Neurological Institute Carlo Besta; Milan Italy
| | - Giovanni Carriero
- Unit of Epileptology and Experimental Neurophysiology; Fondazione Neurological Institute Carlo Besta; Milan Italy
| | - Alessandro Cattalini
- Unit of Epileptology and Experimental Neurophysiology; Fondazione Neurological Institute Carlo Besta; Milan Italy
| | - Barbara Galbardi
- Bioinformatics Unit of Scientific Direction; Neurological Institute Carlo Besta; Milan Italy
| | - Vadym Gnatkovsky
- Unit of Epileptology and Experimental Neurophysiology; Fondazione Neurological Institute Carlo Besta; Milan Italy
| | - Marco de Curtis
- Unit of Epileptology and Experimental Neurophysiology; Fondazione Neurological Institute Carlo Besta; Milan Italy
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27
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Boido D, Kapetis D, Gnatkovsky V, Pastori C, Galbardi B, Sartori I, Tassi L, Cardinale F, Francione S, de Curtis M. Stimulus-evoked potentials contribute to map the epileptogenic zone during stereo-EEG presurgical monitoring. Hum Brain Mapp 2014; 35:4267-81. [PMID: 24706574 PMCID: PMC6869715 DOI: 10.1002/hbm.22516] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Revised: 02/03/2014] [Accepted: 03/18/2014] [Indexed: 11/07/2022] Open
Abstract
Presurgical monitoring with intracerebral electrodes in patients with drug-resistant focal epilepsy represents a standard invasive procedure to localize the sites of seizures origin, defined as the epileptogenic zone (EZ). During presurgical evaluation, intracerebral single-pulse electrical stimulation (SPES) is performed to define the boundaries of eloquent areas and to evoke seizure-associated symptoms. Extensive intracranial exploration and stimulation generate a large dataset on brain connectivity that can be used to improve EZ detection and to understand the organization of the human epileptic brain. We developed a protocol to analyse field responses evoked by intracranial stimulation. Intracerebral recordings were performed with 105-162 recording sites positioned in fronto-temporal regions in 12 patients with pharmacoresistant focal epilepsy. Recording sites were used for bipolar SPES at 1 Hz. Reproducible early and late phases (<60 ms and 60-500 ms from stimulus artefact, respectively) were identified on averaged evoked responses. Phase 1 and 2 responses recorded at all and each recording sites were plotted on a 3D brain reconstructions. Based on connectivity properties, electrode contacts were primarily identified as receivers, mainly activators or bidirectional. We used connectivity patterns to construct networks and applied cluster partitioning to study the proprieties between potentials evoked/stimulated in different regions. We demonstrate that bidirectional connectivity during phase 1 is a prevalent feature that characterize contacts included in the EZ. This study shows that the application of an analytical protocol on intracerebral stimulus-evoked recordings provides useful information that may contribute to EZ detection and to the management of surgical-remediable epilepsies.
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Affiliation(s)
- Davide Boido
- Experimental Neurophysiology and Epileptology UnitFondazione Istituto Neurologico Carlo BestaMilanoItaly
| | - Dimos Kapetis
- Bioinformatics Unit of Scientific DirectionFondazione Istituto Neurologico Carlo BestaMilanoItaly
| | - Vadym Gnatkovsky
- Experimental Neurophysiology and Epileptology UnitFondazione Istituto Neurologico Carlo BestaMilanoItaly
| | - Chiara Pastori
- Experimental Neurophysiology and Epileptology UnitFondazione Istituto Neurologico Carlo BestaMilanoItaly
| | - Barbara Galbardi
- Bioinformatics Unit of Scientific DirectionFondazione Istituto Neurologico Carlo BestaMilanoItaly
| | - Ivana Sartori
- Claudio Munari Epilepsy Surgery CenterOspedale Niguarda Cà GrandaMilanoItaly
| | - Laura Tassi
- Claudio Munari Epilepsy Surgery CenterOspedale Niguarda Cà GrandaMilanoItaly
| | - Francesco Cardinale
- Claudio Munari Epilepsy Surgery CenterOspedale Niguarda Cà GrandaMilanoItaly
| | - Stefano Francione
- Claudio Munari Epilepsy Surgery CenterOspedale Niguarda Cà GrandaMilanoItaly
| | - Marco de Curtis
- Experimental Neurophysiology and Epileptology UnitFondazione Istituto Neurologico Carlo BestaMilanoItaly
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28
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Deleo F, Matricardi S, Didato G, Montano N, Gnatkovsky V, Romito LM, Battaglia G, Spreafico R, Villani F. An unusual behavioural and motor paroxysmal disorder caused by insulinoma-related hypoglycemia: a possible cause of epilepsy misdiagnosis. Seizure 2014; 23:909-11. [PMID: 25088567 DOI: 10.1016/j.seizure.2014.06.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Revised: 06/29/2014] [Accepted: 06/30/2014] [Indexed: 10/25/2022] Open
Affiliation(s)
- Francesco Deleo
- Clinical Epileptology and Experimental Neurophysiology Unit, Fondazione IRCCS, Istituto Neurologico 'C. Besta', Milan, Italy
| | - Sara Matricardi
- Department of Pediatric Neuroscience, Fondazione IRCCS, Istituto Neurologico 'C. Besta', Milan, Italy; Department of Pediatrics, University of Chieti, Chieti, Italy
| | - Giuseppe Didato
- Clinical Epileptology and Experimental Neurophysiology Unit, Fondazione IRCCS, Istituto Neurologico 'C. Besta', Milan, Italy
| | - Nicola Montano
- Department of Clinical Sciences, Internal Medicine II, L. Sacco Hospital, University of Milan, Ospedale L. Sacco, Milan, Italy
| | - Vadym Gnatkovsky
- Experimental Neurophysiology and Epileptology Unit, Fondazione IRCCS, Istituto Neurologico 'C. Besta', Milan, Italy
| | - Luigi Michele Romito
- Movement Disorders Unit, Fondazione IRCCS, Istituto Neurologico 'C. Besta', Milan, Italy
| | - Giorgio Battaglia
- Molecular Neuroanatomy and Pathogenesis Unit, Fondazione IRCCS, Istituto Neurologico 'C. Besta', Milan, Italy
| | - Roberto Spreafico
- Clinical Epileptology and Experimental Neurophysiology Unit, Fondazione IRCCS, Istituto Neurologico 'C. Besta', Milan, Italy
| | - Flavio Villani
- Clinical Epileptology and Experimental Neurophysiology Unit, Fondazione IRCCS, Istituto Neurologico 'C. Besta', Milan, Italy.
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29
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Boido D, Gnatkovsky V, Uva L, Francione S, de Curtis M. Simultaneous enhancement of excitation and postburst inhibition at the end of focal seizures. Ann Neurol 2014; 76:826-36. [PMID: 24916758 DOI: 10.1002/ana.24193] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Revised: 06/04/2014] [Accepted: 06/04/2014] [Indexed: 11/10/2022]
Abstract
OBJECTIVE Comprehension of the events that lead to seizure termination contributes to the development of strategies to confine propagation of ictal discharges. It is commonly assumed that the inhibitory control fails during seizures and recovers after the end of the ictal event. We examine the possibility that a progressive increase of inhibition that counters an increase in the strength of excitation contributes to terminating a focal seizure. METHODS We analyzed seizures acutely induced by pharmacological manipulations (bicuculline and 4-aminopyridine) in the entorhinal cortex and in the hippocampus of the in vitro isolated guinea pig brain. RESULTS As seizures ended, extracellular and intracellular recordings showed periodic bursting that progressively decreased in frequency. During the late bursting phase, the duration, number, and rate of occurrence of spikes within single bursts remained constant, whereas cumulative spike amplitude (index of excitation during a burst) and interburst interval (index of inhibition between bursts) progressively increased. The increment of average/cumulative burst excitation and interburst interval toward seizure end was confirmed in human focal seizures recorded with intracerebral electrodes in patients with drug-resistant partial epilepsies. A postburst refractory period of circa 2 seconds that increases with time toward the end of the seizure was confirmed in the experimental model by probing interburst epochs in the CA1 region with local dentate gyrus stimulation just suprathreshold for burst generation. INTERPRETATION Our findings support the concept that focal seizures are terminated by the simultaneous and opposing enhancement of excitation (burst activity) in addition to postburst inhibition. We hypothesize that a seizure stops when postburst inhibition becomes large enough to prevent reactivation of excitation.
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Affiliation(s)
- Davide Boido
- Unit of Epileptology and Experimental Neurophysiology, Carlo Besta Neurological Institute Foundation, Milan, Italy
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30
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Gnatkovsky V, de Curtis M, Pastori C, Cardinale F, Lo Russo G, Mai R, Nobili L, Sartori I, Tassi L, Francione S. Biomarkers of epileptogenic zone defined by quantified stereo-EEG analysis. Epilepsia 2014; 55:296-305. [PMID: 24417731 DOI: 10.1111/epi.12507] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/04/2013] [Indexed: 12/24/2022]
Abstract
OBJECTIVE In one third of patients with a diagnosis of pharmacoresistant focal epilepsy who are candidates for therapeutic surgery, cerebral areas responsible for seizure generation can be defined exclusively with invasive intracranial recordings. A correct presurgical identification of the epileptogenic zone (EZ) with intracranial electrodes has a direct impact on postsurgical outcome. We aimed at identifying biomarkers of the EZ based on computer-assisted inspection of intracranial electroencephalography (EEG). METHODS Computer-driven intracranial EEG analysis in the domains of time, frequency, and space was retrospectively applied to a population of 10 patients with focal epilepsy to detect EZ electrophysiologic markers. Next, a prospective study was performed on 14 surgery candidate patients. The stereo-EEG computer-assisted analysis of EZ boundaries performed blind from patients data was compared to that defined with the traditional visual inspection completed by neurophysiologists. RESULTS In the retrospective study, the EZ was characterized by the combined detection of three biomarkers observed at seizure onset: (1) fast activity at 80-120 Hz associated with (2) very slow transient polarizing shift and (3) voltage depression (flattening). Correlations between these indexes were calculated for each seizure. In the prospective study, the quantified analysis based on the three biomarkers confirmed a complete overlap between leads within the EZ identified by expert clinicians. In 2 of 14 patients the proposed biomarkers partially identified the EZ. SIGNIFICANCE Our findings demonstrate and validate with a prospective unbiased study the use of three neurophysiologic intracranial EEG parameters as excellent biomarkers of ictogenesis and as reliable indicators of EZ boundaries.
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Affiliation(s)
- Vadym Gnatkovsky
- Unit of Experimental Neurophysiology and Epileptology, Foundation of the Carlo Besta Neurological Institute, Milan, Italy
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31
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Carriero G, Arcieri S, Cattalini A, Corsi L, Gnatkovsky V, de Curtis M. A guinea pig model of mesial temporal lobe epilepsy following nonconvulsive status epilepticus induced by unilateral intrahippocampal injection of kainic acid. Epilepsia 2012; 53:1917-27. [DOI: 10.1111/j.1528-1167.2012.03669.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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32
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Trombin F, Gnatkovsky V, de Curtis M. Changes in action potential features during focal seizure discharges in the entorhinal cortex of the in vitro isolated guinea pig brain. J Neurophysiol 2011; 106:1411-23. [PMID: 21676935 DOI: 10.1152/jn.00207.2011] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Temporal lobe seizures in humans correlate with stereotyped electrophysiological patterns that can be reproduced in animal models to study the cellular and network changes responsible for ictogenesis. Seizure-like discharges that mimic seizure patterns in humans were induced in the entorhinal cortex of the in vitro isolated guinea pig brain by 3-min arterial applications of the GABA(A) receptor antagonist bicuculline. The onset of seizure is characterized by a paradoxical interruption of firing for several seconds in principal neurons coupled with both enhanced interneuronal firing and increased extracellular potassium (Gnatkovsky et al. 2008). The evolution of action potential features from firing break to excessive and synchronous activity associated with the progression of seizure itself is analyzed here. We utilized phase plot analysis to characterize action potential features of entorhinal cortex neurons in different phases of a seizure. Compared with preictal action potentials, resumed spikes in layer II-III neurons (n = 17) during the early phase of the seizure-like discharge displayed 1) depolarized threshold, 2) lower peak amplitude, 3) depolarized voltage of repolarization and 4) decelerated depolarizing phase, and 5) spike doublettes. Action potentials in deep-layer principal cells (n = 8) during seizure did not show the marked feature changes observed in superficial layer neurons. Action potential reappearance correlated with an increase in extracellular potassium. High-threshold, slow-action potentials similar to those observed in the irregular firing phase of a seizure were reproduced in layer II-III neurons by direct cortical application of a highly concentrated potassium solution (12-24 mM). We propose that the generation of possibly nonsomatic action potentials by increased extracellular potassium represents a crucial step toward reestablish firing after an initial depression in an acute model of temporal lobe seizures. Resumed firing reengages principal neurons into seizure discharge and promotes the transition toward the synchronized burst firing that characterizes the late phase of a seizure.
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Affiliation(s)
- Federica Trombin
- Unit of Experimental Neurophysiology and Epileptology, Fondazione Istituto Neurologico Carlo Besta, via Celoria 11, 20133 Milan, Italy
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33
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Gnatkovsky V, Francione S, Cardinale F, Mai R, Tassi L, Lo Russo G, de Curtis M. Identification of reproducible ictal patterns based on quantified frequency analysis of intracranial EEG signals. Epilepsia 2011; 52:477-88. [PMID: 21269289 DOI: 10.1111/j.1528-1167.2010.02931.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Vadym Gnatkovsky
- Unit of Experimental Neurophysiology and Epileptology, Fondazione Istituto Neurologico, Milano, Italy.
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34
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Carriero G, Uva L, Gnatkovsky V, Avoli M, de Curtis M. Independent epileptiform discharge patterns in the olfactory and limbic areas of the in vitro isolated Guinea pig brain during 4-aminopyridine treatment. J Neurophysiol 2010; 103:2728-36. [PMID: 20220076 DOI: 10.1152/jn.00862.2009] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
In vitro studies performed on brain slices demonstrate that the potassium channel blocker 4-aminopyridine (4AP, 50 microM) discloses electrographic seizure activity and interictal discharges. These epileptiform patterns have been further analyzed here in a isolated whole guinea pig brain in vitro by using field potential recordings in olfactory and limbic structures. In 8 of 13 experiments runs of fast oscillatory activity (fast runs, FRs) in the piriform cortex (PC) propagated to the lateral entorhinal cortex (EC), hippocampus and occasionally to the medial EC. Early and late FRs were asynchronous in the hemispheres showed different duration [1.78 +/- 0.51 and 27.95 +/- 4.55 (SD) s, respectively], frequency of occurrence (1.82 +/- 0.49 and 34.16 +/- 6.03 s) and frequency content (20-40 vs. 40-60 Hz). Preictal spikes independent from the FRs appeared in the hippocampus/EC and developed into ictal-like discharges that did not propagate to the PC. Ictal-like activity consisted of fast activity with onset either in the hippocampus (n = 6) or in the mEC (n = 2), followed by irregular spiking and sequences of diffusely synchronous bursts. Perfusion of the N-methyl-d-aspartate receptor antagonist 2-amino-5-phosphonopentanoic acid (100 microM) did not prevent FRs, increased the duration of limbic ictal-like discharges and favored their propagation to olfactory structures. The AMPA receptor antagonist 6,7-dinitroquinoxaline-2,3-dione (50 microM) blocked ictal-like events and reduced FRs. In conclusion, 4AP-induced epileptiform activities are asynchronous and independent in olfactory and hippocampal-entorhinal regions. Epileptiform discharges in the isolated guinea pig brain show different pharmacological properties compared with rodent in vitro slices.
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Affiliation(s)
- Giovanni Carriero
- Unit of Experimental Neurophysiology and Epileptology, Fondazione Istituto Neurologico Carlo Besta, Milano, Italy
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35
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Biella G, Spaiardi P, Toselli M, de Curtis M, Gnatkovsky V. Functional interactions within the parahippocampal region revealed by voltage-sensitive dye imaging in the isolated guinea pig brain. J Neurophysiol 2009; 103:725-32. [PMID: 19939958 DOI: 10.1152/jn.00722.2009] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The massive transfer of information from the neocortex to the entorhinal cortex (and vice versa) is hindered by a powerful inhibitory control generated in the perirhinal cortex. In vivo and in vitro experiments performed in rodents and cats support this conclusion, further extended in the present study to the analysis of the interaction between the entorhinal cortex and other parahippocampal areas, such as the postrhinal and the retrosplenial cortices. The experiments were performed in the in vitro isolated guinea pig brain by a combined approach based on electrophysiological recordings and fast imaging of optical signals generated by voltage-sensitive dyes applied to the entire brain by arterial perfusion. Local stimuli delivered in different portions of the perirhinal, postrhinal, and retrosplenial cortex evoked local responses that did not propagate to the entorhinal cortex. Neither high- and low-frequency-patterned stimulation nor paired associative stimuli facilitated the propagation of activity to the entorhinal region. Similar stimulations performed during cholinergic neuromodulation with carbachol were also ineffective in overcoming the inhibitory network that controls propagation to the entorhinal cortex. The pharmacological inactivation of GABAergic transmission by local application of bicuculline (1 mM) in area 36 of the perirhinal cortex facilitated the longitudinal (rostrocaudal) propagation of activity into the perirhinal/postrhinal cortices but did not cause propagation into the entorhinal cortex. Bicuculline injection in both area 35 and medial entorhinal cortex released the inhibitory control and allowed the propagation of the neural activity to the entorhinal cortex. These results demonstrate that, as for the perirhinal-entorhinal reciprocal interactions, also the connections between the postrhinal/retrosplenial cortices and the entorhinal region are subject to a powerful inhibitory control.
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Affiliation(s)
- Gerardo Biella
- Dipartimento di Fisiologia, Università di Pavia, Pavia, Italy
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Abstract
The mechanisms that control the transition into a focal seizure are still uncertain. The introduction of presurgical intracranial recordings to localize the epileptogenic zone in patients with drug-resistant focal epilepsies opened a new window to the interpretation of seizure generation (ictogenesis). One of the most frequent focal patterns observed with intracranial electrodes at seizure onset is characterized by low-voltage fast activity in the beta-gamma range that may or may not be preceded by changes of ongoing interictal activities. In the present commentary, the mechanisms of generation of focal seizures are reconsidered, focusing on low-voltage fast activity patterns. Experimental findings on models of temporal lobe seizures support the view that the low-voltage fast activity observed at seizure onset is associated with reinforcement and synchronization of inhibitory networks. A minor role for the initiation of the ictal pattern is played by principal neurons that are progressively recruited with a delay, when inhibition declines and synchronous high-voltage discharges ensue. The transition from inhibition into excitatory recruitment is probably mediated by local increase in potassium concentration associated with synchronized interneuronal firing. These findings challenge the classical theory that proposes an increment of excitation and/or a reduction of inhibition as a cause for the transition to seizure in focal epilepsies. A new definition of ictogenesis mechanisms, as herewith hypothesized, might possibly help to develop new therapeutic strategies for focal epilepsies.
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Affiliation(s)
- Marco de Curtis
- Unit of Experimental Neurophysiology and Epileptology, Fondazione Istituto Neurologico Carlo Besta, Milano, Italy.
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Gnatkovsky V, Librizzi L, Trombin F, de Curtis M. Fast activity at seizure onset is mediated by inhibitory circuits in the entorhinal cortex in vitro. Ann Neurol 2008; 64:674-86. [DOI: 10.1002/ana.21519] [Citation(s) in RCA: 160] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Carriero G, Uva L, Gnatkovsky V, de Curtis M. Distribution of the olfactory fiber input into the olfactory tubercle of the in vitro isolated guinea pig brain. J Neurophysiol 2008; 101:1613-9. [PMID: 18922946 DOI: 10.1152/jn.90792.2008] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The olfactory tubercle (OT) is a cortical component of the olfactory system involved in reward mechanisms of drug abuse. This region covers an extensive part of the rostral ventral cerebrum and is relatively poorly studied. The intrinsic network interactions evoked by olfactory input are analyzed in the OT of the in vitro isolated guinea pig brain by means of field potential analysis and optical imaging of voltage-sensitive signals. Stimulation of the lateral olfactory tract induces a monosynaptic response that progressively decreases in amplitude from lateral to medial. The monosynaptic input induces a disynaptic response that is proportionally larger in the medial portion of the OT. Direct stimulation of the piriform cortex and subsequent lesion of this pathway showed the existence of an associative disynaptic projection from the anterior part of the piriform cortex to the lateral part of the OT that integrates with the component mediated by the local intra-OT collaterals. Optical and electrophysiological recordings of the signals evoked by stimulation of the olfactory tract during arterial perfusion with the voltage-sensitive dye di-2-ANEPEQ confirmed the pattern of distribution of the mono and disynaptic responses in the OT. Finally, current source density analysis of laminar profiles recorded with 16-channel silicon probes confirmed that the monosynaptic and disynaptic potentials localize in the most superficial and the deep portions of the plexiform layer I, as suggested by previous reports. This study sets the standard for further analysis of the modulation of network properties in this largely unexplored brain region.
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Affiliation(s)
- Giovanni Carriero
- Unit of Experimental Epileptology and Neurophisiology, Fondazione Istituto Neurologico Carlo Besta, via Celoria 11, 20133 Milano, Italy
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Gnatkovsky V, Wendling F, de Curtis M. Cellular correlates of spontaneous periodic events in the medial entorhinal cortex of the in vitro isolated guinea pig brain. Eur J Neurosci 2007; 26:302-11. [PMID: 17650108 DOI: 10.1111/j.1460-9568.2007.05667.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Periodic potentials characterized by fast oscillations superimposed on a slow complex event are typically observed in cortical structures during sleep and anaesthesia. In the entorhinal cortex (EC) similar spontaneous periodic events (SPEs) have been described both in vivo and in vitro. Simultaneous extracellular and intracellular recordings from superficial neurons of the entorhinal cortex of the isolated Hartley guinea pig brain preparation demonstrated that SPEs recur with a periodicity of 2-10 s and correlate to neuronal firing superimposed on a depolarizing plateau that lasts 0.7-1 s. During SPEs, putative interneurons in all layers discharged high frequency firing (> 100 Hz), whereas no activity was observed in principal neurons of deep entorhinal cortex layers. Linear correlation analysis demonstrated a tight relationship between the fast component of the extracellular SPE and subthreshold oscillatory activity/neuronal firing in both superficial neurons and putative interneurons; firing of deep principal cells was independent from SPEs occurrence. The present study demonstrates that recurrent spontaneous events analogous to periodic activity observed during sleep/anaesthesia are generated in the entorhinal cortex by the interactions between superficial neurons and interneurons.
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Affiliation(s)
- Vadym Gnatkovsky
- Department of Experimental Neurophysiology, Fondazione Istituto Neurologico, via Celoria 11, 20133 Milan, Italy
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Gnatkovsky V, de Curtis M. Hippocampus-mediated activation of superficial and deep layer neurons in the medial entorhinal cortex of the isolated guinea pig brain. J Neurosci 2006; 26:873-81. [PMID: 16421307 PMCID: PMC6675375 DOI: 10.1523/jneurosci.4365-05.2006] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The entorhinal cortex (EC) is regarded as the structure that regulates information flow to and from the hippocampus. It is commonly assumed that superficial and deep EC neurons project to and receive from the hippocampal formation, respectively. Anatomical evidences suggest that both the hippocampal output and deep EC neurons also project to superficial EC layers. To functionally characterize the interlaminar synaptic EC circuit entrained the by hippocampal output, we performed simultaneous intracellular recordings and laminar profile analysis in the medial EC (m-EC) of the in vitro isolated guinea pig brain after polysynaptic hippocampal activation by lateral olfactory tract (LOT) stimulation. Optical imaging of voltage-generated signals confirmed that the LOT-evoked hippocampus-mediated response is restricted to the m-EC. The hippocampal output generated an extracellular current sink in layers V-VI, coupled with an EPSP in deep neurons. Deep neuron firing was terminated by a biphasic IPSP. The earliest response observed in superficial layer neurons was characterized by a feedforward IPSP of circa 100 ms (-69 +/- 1.3 mV reversal potential) abolished by local application of 1 mm bicuculline. The feedforward IPSP was followed by a delayed EPSP blocked by AP-5 (100 microM), presumably mediated by deep-to-superficial m-EC connections. Our findings demonstrate that superficial m-EC cells are inhibited by the hippocampal output via a feedforward pathway that prevents activity reverberation in the hippocampal-EC-hippocampal loop. We propose that such inhibition could serve as a protective mechanism to prevent epileptic hyperexcitability.
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Affiliation(s)
- Vadym Gnatkovsky
- Unit of Clinical Epileptology and Experimental Neurophysiology, Istituto Nazionale Neurologico, 20133 Milan, Italy
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Gnatkovsky V, Uva L, de Curtis M. Topographic distribution of direct and hippocampus- mediated entorhinal cortex activity evoked by olfactory tract stimulation. Eur J Neurosci 2004; 20:1897-905. [PMID: 15380011 DOI: 10.1111/j.1460-9568.2004.03627.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Olfactory information is central for memory-related functions, such as recognition and spatial orientation. To understand the role of olfaction in learning and memory, the distribution and propagation of olfactory tract-driven activity in the parahippocampal region needs to be characterized. We recently demonstrated that repetitive stimulation of the olfactory tract in the isolated guinea pig brain preparation induces an early direct activation of the rostrolateral entorhinal region followed by a delayed response in the medial entorhinal cortex (EC), preceded by the interposed activation of the hippocampus. In the present study we performed a detailed topographic analysis of both the early and the delayed entorhinal responses induced by patterned stimulation of the lateral olfactory tract in the isolated guinea pig brain. Bi-dimensional maps of EC activity recorded at 128 recording sites with 4 x 4 matrix electrodes (410 microm interlead separation) sequentially placed in eight different positions, showed (i) an early (onset at 16.09 +/- 1.2 ms) low amplitude potential mediated by the monosynaptic LOT input, followed by (ii) an associative potential in the rostral EC which originates from the piriform cortex (onset at 33.2 +/- 2.3 ms), and (iii) a delayed potential dependent on the previous activation of the hippocampus. The sharp component of the delayed response had an onset latency between 52 and 63 ms and was followed by a slow wave. Laminar profile analysis demonstrated that in the caudomedial EC the delayed response was associated with two distinct current sinks located in deep and in superficial layers, whereas in the rostrolateral EC a small-amplitude sink could be detected in the superficial layers exclusively. The present report demonstrates that the output generated by the hippocampal activation is unevenly distributed across different EC subregions and indicates that exclusively the medial and caudal divisions receive a deep-layer input from the hippocampus. In the rostrolateral EC, specific network interactions may be generated by the convergence of the direct olfactory input and the olfaction-driven hippocampal output.
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Affiliation(s)
- Vadym Gnatkovsky
- Department of Experimental Neurophysiology, Istituto Nazionale Neurologico Carlo Besta, via Celoria 11, 20133 Milano, Italy
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Biella GR, Gnatkovsky V, Takashima I, Kajiwara R, Iijima T, de Curtis M. Olfactory input to the parahippocampal region of the isolated guinea pig brain reveals weak entorhinal-to-perirhinal interactions. Eur J Neurosci 2003; 18:95-101. [PMID: 12859341 DOI: 10.1046/j.1460-9568.2003.02730.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The processing of olfactory inputs by the parahippocampal region has a central role in the organization of memory in mammals. The olfactory input is relayed to the hippocampus via interposed synapses located in the piriform and entorhinal cortices. Whether olfactory afferents directly or indirectly project to other areas of the parahippocampal region beside the entorhinal cortex (EC) is uncertain. We performed an electrophysiological and imaging study of the propagation pattern of the olfactory input carried by the fibres that form the lateral olfactory tract (LOT) into the parahippocampal region of the in vitro isolated guinea pig preparation. Laminar analysis was performed on field potential depth profiles recorded with 16-channel silicon probes at different sites of the insular-parahippocampal cortex. The LOT input induced a large amplitude polysynaptic response in the lateral EC. Following appropriate LOT stimulation, a late response generated by the interposed activation of the hippocampus was observed in the medial EC. LOT stimulation did not induce any local response in area 36 of the perirhinal cortex (PRC), while a small amplitude potential with a delay similar to the lateral EC response was inconsistently observed in PRC area 35. No PRC potentials were observed following the responses evoked by LOT stimulation in either the lateral or the medial EC. These findings were substantiated by current source density analysis of PRC laminar profiles. To further verify the absence of EC-to-PRC field interactions after LOT stimulation, high-resolution optical imaging of neuronal activity was performed after perfusion of the isolated brain with the voltage-sensitive dye RH-795. The optical recordings confirmed that olfactory-induced activity in the EC does not induce massive PRC activation. The present findings suggest that the olfactory input into the parahippocampal region is confined to the entorhinal cortex. The results also imply that, as demonstrated for the PRC-to-EC pathway, the propagation of neuronal activity from the EC to the PRC is hindered, possibly by a powerful inhibitory control generated within the EC.
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Affiliation(s)
- G R Biella
- Dipartimento Neurofisiologia Sperimentale, Istituto Nazionale Neurologico, Milano, Italy.
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