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Campos-Rodriguez C, Palmer D, Forcelli PA. Optogenetic stimulation of the superior colliculus suppresses genetic absence seizures. Brain 2023; 146:4320-4335. [PMID: 37192344 PMCID: PMC11004938 DOI: 10.1093/brain/awad166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Revised: 04/18/2023] [Accepted: 05/01/2023] [Indexed: 05/18/2023] Open
Abstract
While anti-seizure medications are effective for many patients, nearly one-third of individuals have seizures that are refractory to pharmacotherapy. Prior studies using evoked preclinical seizure models have shown that pharmacological activation or excitatory optogenetic stimulation of the deep and intermediate layers of the superior colliculus (DLSC) display multi-potent anti-seizure effects. Here we monitored and modulated DLSC activity to suppress spontaneous seizures in the WAG/Rij genetic model of absence epilepsy. Female and male WAG/Rij adult rats were employed as study subjects. For electrophysiology studies, we recorded single unit activity from microwire arrays placed within the DLSC. For optogenetic experiments, animals were injected with virus coding for channelrhodopsin-2 or a control vector, and we compared the efficacy of continuous neuromodulation to that of closed-loop neuromodulation paradigms. For each, we compared three stimulation frequencies on a within-subject basis (5, 20, 100 Hz). For closed-loop stimulation, we detected seizures in real time based on the EEG power within the characteristic frequency band of spike-and-wave discharges (SWDs). We quantified the number and duration of each SWD during each 2 h-observation period. Following completion of the experiment, virus expression and fibre-optic placement was confirmed. We found that single-unit activity within the DLSC decreased seconds prior to SWD onset and increased during and after seizures. Nearly 40% of neurons displayed suppression of firing in response to the start of SWDs. Continuous optogenetic stimulation of the DLSC (at each of the three frequencies) resulted in a significant reduction of SWDs in males and was without effect in females. In contrast, closed-loop neuromodulation was effective in both females and males at all three frequencies. These data demonstrate that activity within the DLSC is suppressed prior to SWD onset, increases at SWD onset, and that excitatory optogenetic stimulation of the DLSC exerts anti-seizure effects against absence seizures. The striking difference between open- and closed-loop neuromodulation approaches underscores the importance of the stimulation paradigm in determining therapeutic effects.
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Affiliation(s)
| | - Devin Palmer
- Department of Pharmacology and Physiology, Georgetown University, Washington, DC 20007, USA
- Interdisciplinary Program in Neuroscience, Georgetown University, Washington, DC 20007, USA
| | - Patrick A Forcelli
- Department of Pharmacology and Physiology, Georgetown University, Washington, DC 20007, USA
- Interdisciplinary Program in Neuroscience, Georgetown University, Washington, DC 20007, USA
- Department of Neuroscience, Georgetown University, Washington, DC 20007, USA
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2
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Klippel Zanona Q, Alves Marconi G, de Sá Couto Pereira N, Lazzarotto G, Luiza Ferreira Donatti A, Antonio Cortes de Oliveira J, Garcia-Cairasco N, Elisa Calcagnotto M. Absence-like seizures, cortical oscillations abnormalities and decreased anxiety-like behavior in Wistar Audiogenic Rats with cortical microgyria. Neuroscience 2022; 500:26-40. [DOI: 10.1016/j.neuroscience.2022.07.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 06/25/2022] [Accepted: 07/29/2022] [Indexed: 10/16/2022]
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3
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de Oliveira TVHF, Cukiert A. Deep Brain Stimulation for Treatment of Refractory Epilepsy. Neurol India 2021; 68:S268-S277. [PMID: 33318361 DOI: 10.4103/0028-3886.302454] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Deep brain stimulation (DBS) has been used in the treatment of motor diseases with remarkable safety and efficacy, which abet the interest of its application in the management of other neurologic and psychiatric disorders such as epilepsy. Experimental data demonstrated that electric current could modulate distinct brain circuits and decrease the neuronal hypersynchronization seen in epileptic activity. The ability to carefully choose the most suitable anatomical target as well as to define the most reasonable stimulation parameters is highly dependable on the comprehension of the underlying mechanisms of action, which remain unclear. This review aimed to explore the relevant clinical data regarding the use of DBS in the treatment of refractory epilepsy.
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Affiliation(s)
| | - Arthur Cukiert
- Department of Neurosurgery, Epilepsy Surgery Program, Clínica Cukiert, São Paulo, Brazil
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4
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Crunelli V, Lőrincz ML, McCafferty C, Lambert RC, Leresche N, Di Giovanni G, David F. Clinical and experimental insight into pathophysiology, comorbidity and therapy of absence seizures. Brain 2020; 143:2341-2368. [PMID: 32437558 PMCID: PMC7447525 DOI: 10.1093/brain/awaa072] [Citation(s) in RCA: 88] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 12/19/2019] [Accepted: 01/31/2020] [Indexed: 12/24/2022] Open
Abstract
Absence seizures in children and teenagers are generally considered relatively benign because of their non-convulsive nature and the large incidence of remittance in early adulthood. Recent studies, however, show that 30% of children with absence seizures are pharmaco-resistant and 60% are affected by severe neuropsychiatric comorbid conditions, including impairments in attention, cognition, memory and mood. In particular, attention deficits can be detected before the epilepsy diagnosis, may persist even when seizures are pharmacologically controlled and are aggravated by valproic acid monotherapy. New functional MRI-magnetoencephalography and functional MRI-EEG studies provide conclusive evidence that changes in blood oxygenation level-dependent signal amplitude and frequency in children with absence seizures can be detected in specific cortical networks at least 1 min before the start of a seizure, spike-wave discharges are not generalized at seizure onset and abnormal cortical network states remain during interictal periods. From a neurobiological perspective, recent electrical recordings and imaging of large neuronal ensembles with single-cell resolution in non-anaesthetized models show that, in contrast to the predominant opinion, cortical mechanisms, rather than an exclusively thalamic rhythmogenesis, are key in driving seizure ictogenesis and determining spike-wave frequency. Though synchronous ictal firing characterizes cortical and thalamic activity at the population level, individual cortico-thalamic and thalamocortical neurons are sparsely recruited to successive seizures and consecutive paroxysmal cycles within a seizure. New evidence strengthens previous findings on the essential role for basal ganglia networks in absence seizures, in particular the ictal increase in firing of substantia nigra GABAergic neurons. Thus, a key feature of thalamic ictogenesis is the powerful increase in the inhibition of thalamocortical neurons that originates at least from two sources, substantia nigra and thalamic reticular nucleus. This undoubtedly provides a major contribution to the ictal decrease in total firing and the ictal increase of T-type calcium channel-mediated burst firing of thalamocortical neurons, though the latter is not essential for seizure expression. Moreover, in some children and animal models with absence seizures, the ictal increase in thalamic inhibition is enhanced by the loss-of-function of the astrocytic GABA transporter GAT-1 that does not necessarily derive from a mutation in its gene. Together, these novel clinical and experimental findings bring about paradigm-shifting views of our understanding of absence seizures and demand careful choice of initial monotherapy and continuous neuropsychiatric evaluation of affected children. These issues are discussed here to focus future clinical and experimental research and help to identify novel therapeutic targets for treating both absence seizures and their comorbidities.
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Affiliation(s)
- Vincenzo Crunelli
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta.,Neuroscience Division, School of Bioscience, Cardiff University, Museum Avenue, Cardiff, UK
| | - Magor L Lőrincz
- Neuroscience Division, School of Bioscience, Cardiff University, Museum Avenue, Cardiff, UK.,Department of Physiology, Faculty of Medicine, University of Szeged, Szeged, Hungary.,Department of Physiology, Anatomy and Neuroscience, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Cian McCafferty
- Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland
| | - Régis C Lambert
- Sorbonne Université, CNRS, INSERM, Neuroscience Paris Seine and Institut de Biologie Paris Seine (NPS - IBPS), Paris, France
| | - Nathalie Leresche
- Sorbonne Université, CNRS, INSERM, Neuroscience Paris Seine and Institut de Biologie Paris Seine (NPS - IBPS), Paris, France
| | - Giuseppe Di Giovanni
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta.,Neuroscience Division, School of Bioscience, Cardiff University, Museum Avenue, Cardiff, UK
| | - François David
- Cerebral dynamics, learning and plasticity, Integrative Neuroscience and Cognition Center - UMR 8002, Paris, France
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5
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Bröer S. Not Part of the Temporal Lobe, but Still of Importance? Substantia Nigra and Subthalamic Nucleus in Epilepsy. Front Syst Neurosci 2020; 14:581826. [PMID: 33381016 PMCID: PMC7768985 DOI: 10.3389/fnsys.2020.581826] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 11/09/2020] [Indexed: 01/15/2023] Open
Abstract
The most researched brain region in epilepsy research is the temporal lobe, and more specifically, the hippocampus. However, numerous other brain regions play a pivotal role in seizure circuitry and secondary generalization of epileptic activity: The substantia nigra pars reticulata (SNr) and its direct input structure, the subthalamic nucleus (STN), are considered seizure gating nuclei. There is ample evidence that direct inhibition of the SNr is capable of suppressing various seizure types in experimental models. Similarly, inhibition via its monosynaptic glutamatergic input, the STN, can decrease seizure susceptibility as well. This review will focus on therapeutic interventions such as electrical stimulation and targeted drug delivery to SNr and STN in human patients and experimental animal models of epilepsy, highlighting the opportunities for overcoming pharmacoresistance in epilepsy by investigating these promising target structures.
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Affiliation(s)
- Sonja Bröer
- Faculty of Veterinary Medicine, Institute of Pharmacology and Toxicology, Freie Universität Berlin, Berlin, Germany
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6
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Gernert M, Feja M. Bypassing the Blood-Brain Barrier: Direct Intracranial Drug Delivery in Epilepsies. Pharmaceutics 2020; 12:pharmaceutics12121134. [PMID: 33255396 PMCID: PMC7760299 DOI: 10.3390/pharmaceutics12121134] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 11/18/2020] [Accepted: 11/21/2020] [Indexed: 02/06/2023] Open
Abstract
Epilepsies are common chronic neurological diseases characterized by recurrent unprovoked seizures of central origin. The mainstay of treatment involves symptomatic suppression of seizures with systemically applied antiseizure drugs (ASDs). Systemic pharmacotherapies for epilepsies are facing two main challenges. First, adverse effects from (often life-long) systemic drug treatment are common, and second, about one-third of patients with epilepsy have seizures refractory to systemic pharmacotherapy. Especially the drug resistance in epilepsies remains an unmet clinical need despite the recent introduction of new ASDs. Apart from other hypotheses, epilepsy-induced alterations of the blood-brain barrier (BBB) are thought to prevent ASDs from entering the brain parenchyma in necessary amounts, thereby being involved in causing drug-resistant epilepsy. Although an invasive procedure, bypassing the BBB by targeted intracranial drug delivery is an attractive approach to circumvent BBB-associated drug resistance mechanisms and to lower the risk of systemic and neurologic adverse effects. Additionally, it offers the possibility of reaching higher local drug concentrations in appropriate target regions while minimizing them in other brain or peripheral areas, as well as using otherwise toxic drugs not suitable for systemic administration. In our review, we give an overview of experimental and clinical studies conducted on direct intracranial drug delivery in epilepsies. We also discuss challenges associated with intracranial pharmacotherapy for epilepsies.
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Affiliation(s)
- Manuela Gernert
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Bünteweg 17, D-30559 Hannover, Germany;
- Center for Systems Neuroscience, D-30559 Hannover, Germany
- Correspondence: ; Tel.: +49-(0)511-953-8527
| | - Malte Feja
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Bünteweg 17, D-30559 Hannover, Germany;
- Center for Systems Neuroscience, D-30559 Hannover, Germany
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7
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Midzyanovskaya IS, Shatskova AB, MacDonald E, Luijtelaar GV, Tuomisto L. Brain Aminergic Deficiency in Absence Epileptic Rats: Dependency on Seizure Severity and Their Functional Coupling at Rest. ACTA ACUST UNITED AC 2020. [DOI: 10.4236/jbbs.2020.101003] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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8
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Descending projections from the substantia nigra pars reticulata differentially control seizures. Proc Natl Acad Sci U S A 2019; 116:27084-27094. [PMID: 31843937 DOI: 10.1073/pnas.1908176117] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Three decades of studies have shown that inhibition of the substantia nigra pars reticulata (SNpr) attenuates seizures, yet the circuits mediating this effect remain obscure. SNpr projects to the deep and intermediate layers of the superior colliculus (DLSC) and the pedunculopontine nucleus (PPN), but the contributions of these projections are unknown. To address this gap, we optogenetically silenced cell bodies within SNpr, nigrotectal terminals within DLSC, and nigrotegmental terminals within PPN. Inhibition of cell bodies in SNpr suppressed generalized seizures evoked by pentylenetetrazole (PTZ), partial seizures evoked from the forebrain, absence seizures evoked by gamma-butyrolactone (GBL), and audiogenic seizures in genetically epilepsy-prone rats. Strikingly, these effects were fully recapitulated by silencing nigrotectal projections. By contrast, silencing nigrotegmental terminals reduced only absence seizures and exacerbated seizures evoked by PTZ. These data underscore the broad-spectrum anticonvulsant efficacy of this circuit, and demonstrate that specific efferent projection pathways differentially control different seizure types.
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9
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Kommajosyula SP, Randall ME, Brozoski TJ, Odintsov BM, Faingold CL. Specific subcortical structures are activated during seizure-induced death in a model of sudden unexpected death in epilepsy (SUDEP): A manganese-enhanced magnetic resonance imaging study. Epilepsy Res 2017. [PMID: 28646692 DOI: 10.1016/j.eplepsyres.2017.05.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Sudden unexpected death in epilepsy (SUDEP) is a major concern for patients with epilepsy. In most witnessed cases of SUDEP generalized seizures and respiratory failure preceded death, and pre-mortem neuroimaging studies in SUDEP patients observed changes in specific subcortical structures. Our study examined the role of subcortical structures in the DBA/1 mouse model of SUDEP using manganese-enhanced magnetic resonance imaging (MEMRI). These mice exhibit acoustically-evoked generalized seizures leading to seizure-induced respiratory arrest (S-IRA) that results in sudden death unless resuscitation is rapidly instituted. MEMRI data in the DBA/1 mouse brain immediately after acoustically-induced S-IRA were compared to data in C57 (control) mice that were exposed to the same acoustic stimulus that did not trigger seizures. The animals were anesthetized and decapitated immediately after seizure in DBA/1 mice and after an equivalent time in control mice. Comparative T1 weighted MEMRI images were evaluated using a 14T MRI scanner and quantified. We observed significant increases in activity in DBA/1 mice as compared to controls at previously-implicated auditory (superior olivary complex) and sensorimotor-limbic [periaqueductal gray (PAG) and amygdala] networks and also in structures in the respiratory network. The activity at certain raphe nuclei was also increased, suggesting activation of serotonergic mechanisms. These data are consistent with previous findings that enhancing the action of serotonin prevents S-IRA in this SUDEP model. Increased activity in the PAG and the respiratory and raphe nuclei suggest that compensatory mechanisms for apnea may have been activated by S-IRA, but they were not sufficient to prevent death. The present findings indicate that changes induced by S-IRA in specific subcortical structures in DBA/1 mice are consistent with human SUDEP findings. Understanding the changes in brain activity during seizure-induced death in animals may lead to improved approaches directed at prevention of human SUDEP.
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Affiliation(s)
- Srinivasa P Kommajosyula
- Department of Pharmacology, Southern Illinois University School of Medicine, P.O. Box 19629, Springfield, IL 62794-9629, United States
| | - Marcus E Randall
- Department of Pharmacology, Southern Illinois University School of Medicine, P.O. Box 19629, Springfield, IL 62794-9629, United States
| | - Thomas J Brozoski
- Department of Surgery/Otolaryngology, Southern Illinois University School of Medicine, P.O. Box 19629, Springfield, IL 62794-9629, United States
| | - Boris M Odintsov
- Beckman Institute, University of Illinois Urbana-Champaign, 405 N. Mathews Ave., Urbana, IL, United States
| | - Carl L Faingold
- Department of Pharmacology, Southern Illinois University School of Medicine, P.O. Box 19629, Springfield, IL 62794-9629, United States.
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10
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Wormuth C, Lundt A, Henseler C, Müller R, Broich K, Papazoglou A, Weiergräber M. Review: Ca v2.3 R-type Voltage-Gated Ca 2+ Channels - Functional Implications in Convulsive and Non-convulsive Seizure Activity. Open Neurol J 2016; 10:99-126. [PMID: 27843503 PMCID: PMC5080872 DOI: 10.2174/1874205x01610010099] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Revised: 05/16/2016] [Accepted: 06/24/2016] [Indexed: 11/22/2022] Open
Abstract
Background: Researchers have gained substantial insight into mechanisms of synaptic transmission, hyperexcitability, excitotoxicity and neurodegeneration within the last decades. Voltage-gated Ca2+ channels are of central relevance in these processes. In particular, they are key elements in the etiopathogenesis of numerous seizure types and epilepsies. Earlier studies predominantly targeted on Cav2.1 P/Q-type and Cav3.2 T-type Ca2+ channels relevant for absence epileptogenesis. Recent findings bring other channels entities more into focus such as the Cav2.3 R-type Ca2+ channel which exhibits an intriguing role in ictogenesis and seizure propagation. Cav2.3 R-type voltage gated Ca2+ channels (VGCC) emerged to be important factors in the pathogenesis of absence epilepsy, human juvenile myoclonic epilepsy (JME), and cellular epileptiform activity, e.g. in CA1 neurons. They also serve as potential target for various antiepileptic drugs, such as lamotrigine and topiramate. Objective: This review provides a summary of structure, function and pharmacology of VGCCs and their fundamental role in cellular Ca2+ homeostasis. We elaborate the unique modulatory properties of Cav2.3 R-type Ca2+ channels and point to recent findings in the proictogenic and proneuroapoptotic role of Cav2.3 R-type VGCCs in generalized convulsive tonic–clonic and complex-partial hippocampal seizures and its role in non-convulsive absence like seizure activity. Conclusion: Development of novel Cav2.3 specific modulators can be effective in the pharmacological treatment of epilepsies and other neurological disorders.
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Affiliation(s)
- Carola Wormuth
- Department of Neuropsychopharmacology, Federal Institute for Drugs and Medical Devices (BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175 Bonn, Germany
| | - Andreas Lundt
- Department of Neuropsychopharmacology, Federal Institute for Drugs and Medical Devices (BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175 Bonn, Germany
| | - Christina Henseler
- Department of Neuropsychopharmacology, Federal Institute for Drugs and Medical Devices (BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175 Bonn, Germany
| | - Ralf Müller
- Department of Psychiatry and Psychotherapy, University of Cologne, Faculty of Medicine, Cologne, Germany
| | - Karl Broich
- Department of Neuropsychopharmacology, Federal Institute for Drugs and Medical Devices (BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175 Bonn, Germany
| | - Anna Papazoglou
- Department of Neuropsychopharmacology, Federal Institute for Drugs and Medical Devices (BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175 Bonn, Germany
| | - Marco Weiergräber
- Department of Neuropsychopharmacology, Federal Institute for Drugs and Medical Devices (BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175 Bonn, Germany
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Kim YS, Park J, Park Y, Hwang K, Koo DL, Kim D, Seo DW. Intracranial Cortical Calcifications in a Focal Epilepsy Patient with Pseudohypoparathyroidism. J Epilepsy Res 2016; 6:31-5. [PMID: 27390678 PMCID: PMC4933679 DOI: 10.14581/jer.16006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2016] [Accepted: 03/14/2016] [Indexed: 12/02/2022] Open
Abstract
Patients with chronic parathyroid dysfunction often have intracranial calcification in deep gray matter (GM) and subcortical white matter (WM) of their brain. Some of them are also epilepsy patients. Although cortical etiologies are main cause of epileptic seizure, cortical calcification has not been reported in these patients. We report a newly diagnosed focal epilepsy patient whose brain magnetic resonance imaging revealed intracranial calcifications in cortical as well as subcortical areas. Blood lab revealed that he had hypocalcemia due to pseudohypoparathyroidism. Video EEG monitoring revealed the ictal EEG mainly consist of polymorphic delta to theta waves with maximum at right temporal area followed by background attenuation and muscle artifacts. The interictal EEG showed multiple focal spike-wave discharges. After given oral calcium and calcitriol supplement, his calcium and phosphorous level normalized and he remains seizure free. This is the first case to show cortical calcification in a patient with pseudohypoparathyroidism. Cortical calcification could be an important measure of seizure burden in these patients and thus sophisticated imaging protocols should be used to visualize the extent of calcium deposits.
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Affiliation(s)
- Ye Sel Kim
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul
| | - Jihyung Park
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul
| | - Yoonkyung Park
- Department of Neurology, Konyang University College of Medicine, Daejeon
| | - KyoungJin Hwang
- Department of Neurology, Kyung Hee University School of Medicine, Seoul, Korea
| | - Dae Lim Koo
- Department of Neurology, Seoul Metropolitan Government Seoul National University Boramae Medical Center, Seoul
| | - Daeyoung Kim
- Department of Neurology, Chungnam National University School of Medicine, Daejeon
| | - Dae-Won Seo
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul;; Neuroscience Center, Samsung Medical Center, Seoul, Korea
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12
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Decreased HCN2 expression in STN contributes to abnormal high-voltage spindles in the cortex and globus pallidus of freely moving rats. Brain Res 2015; 1618:17-28. [DOI: 10.1016/j.brainres.2015.05.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Revised: 05/06/2015] [Accepted: 05/08/2015] [Indexed: 12/23/2022]
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13
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Yang C, Zhang JR, Chen L, Ge SN, Wang JL, Yan ZQ, Jia D, Zhu JL, Gao GD. High frequency stimulation of the STN restored the abnormal high-voltage spindles in the cortex and the globus pallidus of 6-OHDA lesioned rats. Neurosci Lett 2015; 595:122-7. [DOI: 10.1016/j.neulet.2015.04.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Revised: 03/29/2015] [Accepted: 04/04/2015] [Indexed: 11/26/2022]
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14
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Vaudano AE, Ruggieri A, Vignoli A, Canevini MP, Meletti S. Emerging neuroimaging contribution to the diagnosis and management of the ring chromosome 20 syndrome. Epilepsy Behav 2015; 45:155-63. [PMID: 25843339 DOI: 10.1016/j.yebeh.2015.02.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2014] [Revised: 01/28/2015] [Accepted: 02/01/2015] [Indexed: 01/13/2023]
Abstract
Ring chromosome 20 [r(20)] syndrome is an underdiagnosed chromosomal anomaly characterized by severe epilepsy, behavioral problems, and mild-to-moderate cognitive deficits. Since the cognitive and behavioral decline follows seizure onset, this syndrome has been proposed as an epileptic encephalopathy (EE). The recent overwhelming development of advanced neuroimaging techniques has opened a new era in the investigation of the brain networks subserving the EEs. In particular, functional neuroimaging tools are well suited to show alterations related to epileptiform discharges at the network level and to build hypotheses about the mechanisms underlying the cognitive disruption observed in these conditions. This paper reviews the brain circuits and their disruption as revealed by functional neuroimaging studies in patients with [r(20)] syndrome. It discusses the clinical consequences of the neuroimaging findings on the management of patients with [r(20)] syndrome, including their impact to an earlier diagnosis of this disorder. Based on the available lines of evidences, [r(20)] syndrome is characterized by interictal and ictal dysfunctions within basal ganglia-prefrontal lobe networks and by long-lasting effects of the peculiar theta-delta rhythm, which represents an EEG marker of the syndrome on integrated brain networks that subserve cognitive functions.
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Affiliation(s)
- Anna Elisabetta Vaudano
- Department of Biomedical, Metabolic, and Neural Science, University of Modena and Reggio Emilia, Modena, Italy; N.O.C.S.A.E. Hospital, ASL Modena, Italy
| | - Andrea Ruggieri
- Department of Biomedical, Metabolic, and Neural Science, University of Modena and Reggio Emilia, Modena, Italy
| | - Aglaia Vignoli
- Department of Health Sciences, Epilepsy Centre, San Paolo Hospital, University of Milan, Italy
| | - Maria Paola Canevini
- Department of Health Sciences, Epilepsy Centre, San Paolo Hospital, University of Milan, Italy
| | - Stefano Meletti
- Department of Biomedical, Metabolic, and Neural Science, University of Modena and Reggio Emilia, Modena, Italy; N.O.C.S.A.E. Hospital, ASL Modena, Italy.
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15
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Striatal GABAergic and cortical glutamatergic neurons mediate contrasting effects of cannabinoids on cortical network synchrony. Proc Natl Acad Sci U S A 2012; 110:719-24. [PMID: 23269835 DOI: 10.1073/pnas.1217144110] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Activation of type 1 cannabinoid receptors (CB1R) decreases GABA and glutamate release in cortical and subcortical regions, with complex outcomes on cortical network activity. To date there have been few attempts to disentangle the region- and cell-specific mechanisms underlying the effects of cannabinoids on cortical network activity in vivo. Here we addressed this issue by combining in vivo electrophysiological recordings with local and systemic pharmacological manipulations in conditional mutant mice lacking CB1R expression in different neuronal populations. First we report that cannabinoids induce hypersynchronous thalamocortical oscillations while decreasing the amplitude of faster cortical oscillations. Then we demonstrate that CB1R at striatonigral synapses (basal ganglia direct pathway) mediate the thalamocortical hypersynchrony, whereas activation of CB1R expressed in cortical glutamatergic neurons decreases cortical synchrony. Finally we show that activation of CB1 expressed in cortical glutamatergic neurons limits the cannabinoid-induced thalamocortical hypersynchrony. By reporting that CB1R activations in cortical and subcortical regions have contrasting effects on cortical synchrony, our study bridges the gap between cellular and in vivo network effects of cannabinoids. Incidentally, the thalamocortical hypersynchrony we report suggests a potential mechanism to explain the sensory "high" experienced during recreational consumption of marijuana.
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16
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Behavioral and EEG effects of GABAergic manipulation of the nigro-tectal pathway in the Wistar audiogenic rat (WAR) strain II: an EEG wavelet analysis and retrograde neuronal tracer approach. Epilepsy Behav 2012; 24:391-8. [PMID: 22704998 DOI: 10.1016/j.yebeh.2012.04.133] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Accepted: 04/21/2012] [Indexed: 11/23/2022]
Abstract
The role of the substantia nigra pars reticulata (SNPr) and superior colliculus (SC) network in rat strains susceptible to audiogenic seizures still remain underexplored in epileptology. In a previous study from our laboratory, the GABAergic drugs bicuculline (BIC) and muscimol (MUS) were microinjected into the deep layers of either the anterior SC (aSC) or the posterior SC (pSC) in animals of the Wistar audiogenic rat (WAR) strain submitted to acoustic stimulation, in which simultaneous electroencephalographic (EEG) recording of the aSC, pSC, SNPr and striatum was performed. Only MUS microinjected into the pSC blocked audiogenic seizures. In the present study, we expanded upon these previous results using the retrograde tracer Fluorogold (FG) microinjected into the aSC and pSC in conjunction with quantitative EEG analysis (wavelet transform), in the search for mechanisms associated with the susceptibility of this inbred strain to acoustic stimulation. Our hypothesis was that the WAR strain would have different connectivity between specific subareas of the superior colliculus and the SNPr when compared with resistant Wistar animals and that these connections would lead to altered behavior of this network during audiogenic seizures. Wavelet analysis showed that the only treatment with an anticonvulsant effect was MUS microinjected into the pSC region, and this treatment induced a sustained oscillation in the theta band only in the SNPr and in the pSC. These data suggest that in WAR animals, there are at least two subcortical loops and that the one involved in audiogenic seizure susceptibility appears to be the pSC-SNPr circuit. We also found that WARs presented an increase in the number of FG+ projections from the posterior SNPr to both the aSC and pSC (primarily to the pSC), with both acting as proconvulsant nuclei when compared with Wistar rats. We concluded that these two different subcortical loops within the basal ganglia are probably a consequence of the WAR genetic background.
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Saillet S, Gharbi S, Charvet G, Deransart C, Guillemaud R, Depaulis A, David O. Neural adaptation to responsive stimulation: a comparison of auditory and deep brain stimulation in a rat model of absence epilepsy. Brain Stimul 2012; 6:241-7. [PMID: 22727526 DOI: 10.1016/j.brs.2012.05.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2012] [Revised: 05/01/2012] [Accepted: 05/22/2012] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Responsive deep brain stimulation (rDBS) has been recently proposed to block epileptic seizures at onset. Yet, long-term stability of brain responses to such kind of stimulation is not known. OBJECTIVE To quantify the neural adaptation to repeated rDBS as measured by the changes of anti-epileptic efficacy of bilateral DBS of the substantia nigra pars reticulata (SNr) versus auditory stimulation, in a rat model of spontaneous recurrent absence seizures (GAERS). METHODS Local field potentials (LFP) were recorded in freely moving animals during 1 h up to 24 h under automated responsive stimulations (SNr-DBS and auditory). Comparison of seizure features was used to characterise transient (repetition-suppression effect) and long-lasting (stability of anti-epileptic efficacy, i.e. ratio of successfully interrupted seizures) effects of responsive stimulations. RESULTS SNr-DBS was more efficient than auditory stimulation in blocking seizures (97% vs. 52% of seizures interrupted, respectively). Sensitivity to minimal interstimulus interval was much stronger for SNr-DBS than for auditory stimulation. Anti-epileptic efficacy of SNr-DBS was remarkably stable during long-term (24 h) recordings. CONCLUSIONS In the GAERS model, we demonstrated the superiority of SNr-DBS to suppress seizures, as compared to auditory stimulation. Importantly, we found no long-term habituation to rDBS. However, when seizure recurrence was frequent, rDBS lack anti-epileptic efficacy because responsive stimulations became too close (time interval < 40 s) suggesting the existence of a refractory period. This study thus motivates the use of automated rDBS in patients having transient seizures separated by sufficiently long intervals.
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Affiliation(s)
- Sandrine Saillet
- Inserm, U836, Grenoble Institut des Neurosciences, Grenoble, France
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Vinogradova LV, Shatskova AB. Lateral asymmetry of early seizure manifestations in experimental generalized epilepsy. Neuroscience 2012; 213:133-43. [PMID: 22525136 DOI: 10.1016/j.neuroscience.2012.03.060] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Revised: 03/13/2012] [Accepted: 03/14/2012] [Indexed: 10/28/2022]
Abstract
Reorganization of seizure networks during epileptogenesis involves cortico-subcortical and interhemispheric interactions. In the audiogenic kindling (AK) model of generalized tonic-clonic seizures, upstream seizure propagation along ascending brainstem-to-forebrain pathways determines progressive intensification of repeated sound-induced convulsions. Full-blown audiogenic seizures are bilaterally symmetric and their repetition results in bisynchronous recruiting the cortex in secondary epileptogenesis. The present study describes lateral asymmetry of initial behavioral and EEG manifestations of audiogenic seizures and AK in Wistar and WAG/Rij rats with acoustic hypersensitivity. These rats exhibit consistent individual lateralization of running seizures (run directionality) induced by repeated binaural stimulation. Since this initial preconvulsive running reflects seizure onset in the auditory brainstem, the running asymmetry suggests non-symmetric early epileptic activation of brainstem substrates by sound in these rats. Repetition of the asymmetric brainstem seizures led to asynchronous recruiting the cortex into seizure network and lateralization of running seizures was predictive for asymmetry of early cortical seizure manifestations in Wistar and WAG/Rij rats. Both electrographic markers of AK, spreading depression (SD) and post-running afterdischarge, first appeared in the cortex ipsilateral to run direction, suggesting lateralized brainstem-to-forebrain seizure generalization during AK. At the population level, no bias in lateralization of running and SD was found in Wistar and WAG/Rij rats but incidence of secondary cortical seizures varied, depending on strain and run laterality. Among Wistar rats, cortical seizures developed more rarely in right-runners than in left-runners, suggesting enhanced resistance of the right hemisphere to epileptogenesis in rats of this strain. WAG/Rij rats with mixed (absence and audiogenic) epilepsy showed weak lateralization of early cortical seizures and no left-right difference in their incidence during AK. Present findings suggest (1) lateralized brainstem-to-forebrain seizure propagation and hemispheric difference in its facility in Wistar rats, (2) alterations of intra- and interhemispheric seizure propagation in WAG/Rij rats with genetic absence epilepsy.
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Affiliation(s)
- L V Vinogradova
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences - RAS, Butlerova Street 5A, 117485 Moscow, Russia.
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Evolution of the dynamic properties of the cortex-basal ganglia network after dopaminergic depletion in rats. Neurobiol Dis 2012; 46:402-13. [PMID: 22353564 DOI: 10.1016/j.nbd.2012.02.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Revised: 01/18/2012] [Accepted: 02/04/2012] [Indexed: 11/20/2022] Open
Abstract
It is well established that parkinsonian syndrome is associated with alterations of neuronal activity temporal pattern basal ganglia (BG). An increase in synchronized oscillations has been observed in different BG nuclei in Parkinson's disease patients as well as animal models such as 6-hydroxydopamine treated rats. We recently demonstrated that this increase in oscillatory synchronization is present during high-voltage spindles (HVS) probably underpinned by the disorganization of cortex-BG interactions. Here we investigated the time course of both oscillatory and motor alterations. For that purpose we performed daily simultaneous recordings of neuronal activity in motor cortex, striatum and substantia nigra pars reticulata (SNr), before and after 6-hydroxydopamine lesion in awake rats. After a brief non-dopamine-specific desynchronization, oscillatory activity first increased during HVS followed by progressive motor impairment and the shortening of SNr activation delay. While the oscillatory firing increase reflects dopaminergic depletion, response alteration in SNr neurons is closely related to motor symptom.
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Rossetti F, Rodrigues MCA, de Oliveira JAC, Garcia-Cairasco N. Behavioral and EEG effects of GABAergic manipulation of the nigrotectal pathway in the Wistar audiogenic rat strain. Epilepsy Behav 2011; 22:191-9. [PMID: 21820967 DOI: 10.1016/j.yebeh.2011.06.033] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2011] [Revised: 06/22/2011] [Accepted: 06/24/2011] [Indexed: 10/17/2022]
Abstract
The superior colliculus (SC), substantia nigra pars reticulata (SNPr), and striatum have been characterized as important structures involved in the modulation of seizure activity. In the current study, bicuculline (GABA(A) antagonist) and muscimol (GABA(A) agonist) were microinjected into the deep layers of either the anterior SC (aSC) or posterior SC (pSC) of genetically developed Wistar audiogenic rats. Behavior and EEG activity were studied simultaneously. Only muscimol microinjected into the pSC had behavioral and EEG anticonvulsant effects in Wistar audiogenic rats, eliciting EEG oscillation changes in both SNPr and pSC, primarily during tonic seizures. The SC of Wistar audiogenic rats thus comprises two functionally different subregions, pSC and aSC, defined by distinct behavioral and EEG features. The pSC has proconvulsant audiogenic seizure activity in Wistar audiogenic rats. Our data suggest that this phenomenon may be a consequence of the genetic selection of the Wistar audiogenic rat strain.
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Affiliation(s)
- Franco Rossetti
- Neuroscience and Behavioral Sciences Department, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
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21
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The genetics of monogenic idiopathic epilepsies and epileptic encephalopathies. Seizure 2011; 21:3-11. [PMID: 21917483 DOI: 10.1016/j.seizure.2011.08.007] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Revised: 08/06/2011] [Accepted: 08/09/2011] [Indexed: 12/23/2022] Open
Abstract
The group of idiopathic epilepsies encompasses numerous syndromes without known organic substrate. Genetic anomalies are thought to be responsible for pathogenesis, with a monogenic or polygenic model of inheritance. Over the last two decades, a number of genetic anomalies and encoded proteins have been related to particular idiopathic epilepsies and epileptic encephalopathies. Most of these mutations involve subunits of neuronal ion channels (e.g. potassium, sodium, and chloride channels), and may result in abnormal neuronal hyperexcitability manifesting with seizures. However non-ion channel proteins may also be affected. Correlations between genotype and phenotype are not easy to establish, since genetic and non-genetic factors are likely to play a role in determining the severity of clinical features. The growing number of discoveries on this topic are improving classification, prognosis and counseling of patients and families with these forms of epilepsy, and may lead to targeted therapeutic approaches in the near future. In this article the authors have reviewed the main genetic discoveries in the field of the monogenic idiopathic epilepsies and epileptic encephalopathies, in order to provide epileptologists with a concise and comprehensive summary of clinical and genetic features of these seizure disorders.
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Shehab S, Al-Nahdi A, Al-Zaabi F, Al-Mugaddam F, Al-Sultan M, Ljubisavljevic M. Effective inhibition of substantia nigra by deep brain stimulation fails to suppress tonic epileptic seizures. Neurobiol Dis 2011; 43:725-35. [DOI: 10.1016/j.nbd.2011.06.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Revised: 05/22/2011] [Accepted: 06/06/2011] [Indexed: 11/28/2022] Open
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Pro-epileptic effects of the cannabinoid receptor antagonist SR141716 in a model of audiogenic epilepsy. Epilepsy Res 2011; 96:250-6. [PMID: 21733658 DOI: 10.1016/j.eplepsyres.2011.06.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2011] [Revised: 06/09/2011] [Accepted: 06/11/2011] [Indexed: 01/06/2023]
Abstract
Endocannabinoid system and its CB1 receptors are suggested to provide endogeneous protection against seizures. The present study examines whether CB1 receptors contribute to resistance to seizures and kindling epileptogenesis in a model of audiogenic epilepsy. Three groups of Wistar rats were used: rats unsusceptible to audiogenic seizures, rats with acquired resistance to audiogenic seizures and rats with reproducible audiogenic running seizures. Chronic treatment with the CB1 receptor antagonist SR141716 (5 daily dosing of 30mg/kg) did not change innate resistance to audiogenic seizures in non-epileptic rats but reverted acquired seizure resistance in rats which lost their epileptic sensitivity with repeated testing. In the latter rats, audiogenic running seizures reappeared for at least two weeks after the end of treatment. In rats with reproducible seizure response, acutely, SR lengthened audiogenic seizures due to prolongation or appearance, de novo, of post-running limbic clonus without any effect on running seizure per se. This limbic component mimicked audiogenic kindling and indicated propagation of sound-induced brainstem seizure to the limbic forebrain. After chronic SR administration the incidence of the limbic clonus remained to be increased for at least two weeks. The present study supports the hypothesis about a role of CB1 receptors in endogeneous anticonvulsive mechanisms of the brain.
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Luo C, Li Q, Xia Y, Lei X, Xue K, Yao Z, Lai Y, Martínez-Montes E, Liao W, Zhou D, Valdes-Sosa PA, Gong Q, Yao D. Resting state basal ganglia network in idiopathic generalized epilepsy. Hum Brain Mapp 2011; 33:1279-94. [PMID: 21520351 DOI: 10.1002/hbm.21286] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2010] [Revised: 12/31/2010] [Accepted: 01/18/2011] [Indexed: 11/11/2022] Open
Abstract
The basal ganglia, a brain structure related to motor control, is implicated in the modulation of epileptic discharges generalization in patients with idiopathic generalized epilepsy (IGE). Using group independent component analysis (ICA) on resting-state fMRI data, this study identified a resting state functional network that predominantly consisted of the basal ganglia in both healthy controls and patients with IGE. In order to gain a better understanding of the basal ganglia network(BGN) in IGE patients, we compared the BGN functional connectivity of controls with that of epilepsy patients, either with interictal epileptic discharges (with-discharge period, WDP) or without epileptic discharge (nondischarge period, NDP) while scanning. Compared with controls, functional connectivity of BGN in IGE patients demonstrated significantly more integration within BGN except cerebellum and supplementary motor area (SMA) during both periods. Compared with the NDP group, the increased functional connectivity was found in bilateral caudate nucleus and the putamen, and decreases were observed in the bilateral cerebellum and SMA in WDP group. In accord with the proposal that the basal ganglia modulates epileptic discharge activity, the results showed that the modulation enhanced the integration in BGN of patients, and modulation during WDP was stronger than that during NDP. Furthermore, reduction of functional connectivity in cerebellum and SMA, the abnormality might be further aggravated during WDP, was consistent with the behavioral manifestations with disturbed motor function in IGE. These resting-state fMRI findings in the current study provided evidence confirming the role of the BGN as an important modulator in IGE.
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Affiliation(s)
- Cheng Luo
- Key Laboratory for NeuroInformation of Ministry of Education, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China
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25
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Charpier S, Beurrier C, Paz JT. The Subthalamic Nucleus. ACTA ACUST UNITED AC 2010. [DOI: 10.1016/b978-0-12-374767-9.00015-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
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Abstract
Generalized spike-wave seizures are typically brief events associated with dynamic changes in brain physiology, metabolism, and behavior. Functional magnetic resonance imaging (fMRI) provides a relatively high spatiotemporal resolution method for imaging cortical-subcortical network activity during spike-wave seizures. Patients with spike-wave seizures often have episodes of staring and unresponsiveness which interfere with normal behavior. Results from human fMRI studies suggest that spike-wave seizures disrupt specific networks in the thalamus and frontoparietal association cortex which are critical for normal attentive consciousness. However, the neuronal activity underlying imaging changes seen during fMRI is not well understood, particularly in abnormal conditions such as seizures. Animal models have begun to provide important fundamental insights into the neuronal basis for fMRI changes during spike-wave activity. Work from these models including both fMRI and direct neuronal recordings suggest that, in humans, specific cortical-subcortical networks are involved in spike-wave, while other regions are spared. Regions showing fMRI increases demonstrate correlated increases in neuronal activity in animal models. The mechanisms of fMRI decreases in spike-wave will require further investigation. A better understanding of the specific brain regions involved in generating spike-wave seizures may help guide efforts to develop targeted therapies aimed at preventing or reversing abnormal excitability in these brain regions, ultimately leading to a cure for this disorder.
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Affiliation(s)
- Joshua E. Motelow
- Department of Neurology, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut 06520, USA
| | - Hal Blumenfeld
- Department of Neurology, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut 06520, USA
- Department of Neurobiology, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut 06520, USA
- Department of Neurosurgery, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut 06520, USA
- QNMR, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut 06520, USA
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Velísek L, Velísková J, Chudomel O, Poon KL, Robeson K, Marshall B, Sharma A, Moshé SL. Metabolic environment in substantia nigra reticulata is critical for the expression and control of hypoglycemia-induced seizures. J Neurosci 2008; 28:9349-62. [PMID: 18799669 PMCID: PMC2615494 DOI: 10.1523/jneurosci.3195-08.2008] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2008] [Accepted: 07/31/2008] [Indexed: 11/21/2022] Open
Abstract
Seizures represent a common and serious complication of hypoglycemia. Here we studied mechanisms of control of hypoglycemic seizures induced by insulin injection in fasted and nonfasted rats. We demonstrate that fasting predisposes rats to more rapid and consistent development of hypoglycemic seizures. However, the fasting-induced decrease in baseline blood glucose concentration cannot account for the earlier onset of seizures in fasted versus nonfasted rats. Data obtained with c-Fos immunohistochemistry and [14C]2-deoxyglucose uptake implicate a prominent involvement of the substantia nigra reticulata (SNR) among other structures in the hypoglycemic seizure control. This is supported by data showing that fasting decreases the SNR expression of K(ATP) channels, which link metabolism with activity, and is further confirmed with microinfusions of K(ATP) channel agonist and antagonist. Data obtained with whole-cell and perforated patch recordings from SNR neurons in slices in vitro demonstrate that both presynaptic and postsynaptic K(ATP) channels participate in the failure of the SNR to control hypoglycemic seizures. The results suggest that fasting and insulin-induced hypoglycemia can lead to impairment in the function of the SNR, leading thus to hypoglycemic seizures.
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Affiliation(s)
- Libor Velísek
- The Saul R. Korey Department of Neurology, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
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Stewart LS, Nylen KJ, Persinger MA, Cortez MA, Gibson KM, Snead OC. Circadian distribution of generalized tonic-clonic seizures associated with murine succinic semialdehyde dehydrogenase deficiency, a disorder of GABA metabolism. Epilepsy Behav 2008; 13:290-4. [PMID: 18514581 PMCID: PMC2574901 DOI: 10.1016/j.yebeh.2008.04.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2008] [Revised: 04/17/2008] [Accepted: 04/18/2008] [Indexed: 11/29/2022]
Abstract
Human succinic semialdehyde dehydrogenase (SSADH) deficiency is an autosomal recessive disorder of GABA metabolism associated with motor impairment and epileptic seizures. Similarly, mice with targeted deletion of the Aldh5a1 gene (Aldh5a1(-/-)) exhibit SSADH deficiency and seizures early in life. These seizures begin as absence seizures the second week of life, but evolve into generalized convulsive seizures that increase in severity and become lethal during the fourth postnatal week. The seizures are alleviated and survival is prolonged when the mutant animals are weaned onto a ketogenic diet (KD). The persistence of spontaneous, recurrent, generalized tonic-clonic seizures in KD-treated adult Aldh5a1(-/-) mice allowed us to quantify their daily (circadian) distribution using a novel behavioral method based on the detection of changes in movement velocity. Adult KD-treated Aldh5a1(-/-) mice exhibited a seizure phenotype characterized by fits of wild running clonus accompanied by jumping and bouncing. These hypermotor seizures were largely spontaneous and occurred daily in a nonrandom pattern. The seizure rhythm showed a peak shortly after dark phase onset (2008 hours) with near-24-hour periodicity. Age-matched wild-type littermates showed no evidence of abnormal motor behavior. These new data suggest that generalized tonic-clonic seizures in Aldh5a1(-/-) mice are more frequent during a specific time of day and will provide useful information to clinicians for the treatment of seizures associated with human SSADH deficiency.
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Affiliation(s)
- Lee S. Stewart
- Neurosciences and Mental Health Research Program, The Hospital for Sick Children, 555 University Avenue, Toronto ON, Canada M5G 1X8
| | - Kirk J. Nylen
- Neurosciences and Mental Health Research Program, The Hospital for Sick Children, 555 University Avenue, Toronto ON, Canada M5G 1X8
| | - Michael A. Persinger
- Behavioral Neuroscience Program, Department of Psychology, Laurentian University, Sudbury ON, Canada P3E 2C6
| | - Miguel A. Cortez
- Neurosciences and Mental Health Research Program, The Hospital for Sick Children, 555 University Avenue, Toronto ON, Canada M5G 1X8, Division of Neurology, The Hospital for Sick Children, 555 University Avenue, Toronto ON, Canada M5G 1X8, Department of Pediatrics, Faculty of Medicine, University of Toronto, 190 Elizabeth Street, Toronto ON, Canada M5G 2C4
| | - K. Michael Gibson
- Division of Medical Genetics, Departments of Pediatrics and Pathology, University of Pittsburgh School of Medicine, Rangos Research Center, 3460 Fifth Avenue, Pittsburgh PA 15213, USA
| | - O. Carter Snead
- Neurosciences and Mental Health Research Program, The Hospital for Sick Children, 555 University Avenue, Toronto ON, Canada M5G 1X8, Division of Neurology, The Hospital for Sick Children, 555 University Avenue, Toronto ON, Canada M5G 1X8, Department of Pediatrics, Faculty of Medicine, University of Toronto, 190 Elizabeth Street, Toronto ON, Canada M5G 2C4, Corresponding author. Address: Neurosciences and Mental Health Research Program, The Hospital for Sick Children, 555 University Avenue, Toronto ON, Canada M5G 1X8. Fax: +1 416 813 6334. E-mail address: (O.C. Snead, III)
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Degos B, Deniau JM, Le Cam J, Mailly P, Maurice N. Evidence for a direct subthalamo-cortical loop circuit in the rat. Eur J Neurosci 2008; 27:2599-610. [DOI: 10.1111/j.1460-9568.2008.06229.x] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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30
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Vinogradova LV, Shatskova AB, Tuomisto L. Histaminergic modulation of acoustically induced running behavior in rats. Brain Res 2007; 1148:198-204. [DOI: 10.1016/j.brainres.2007.02.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2006] [Revised: 02/08/2007] [Accepted: 02/09/2007] [Indexed: 11/15/2022]
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31
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Paz JT, Chavez M, Saillet S, Deniau JM, Charpier S. Activity of ventral medial thalamic neurons during absence seizures and modulation of cortical paroxysms by the nigrothalamic pathway. J Neurosci 2007; 27:929-41. [PMID: 17251435 PMCID: PMC6672924 DOI: 10.1523/jneurosci.4677-06.2007] [Citation(s) in RCA: 113] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2006] [Revised: 11/28/2006] [Accepted: 12/17/2006] [Indexed: 11/21/2022] Open
Abstract
Absence seizures are characterized by bilaterally synchronous spike-and-wave discharges (SWDs) in the electroencephalogram, which reflect abnormal oscillations in corticothalamic networks. Although it was suggested that basal ganglia could modulate, via their feedback circuits to the cerebral cortex, the occurrence of SWDs, the cellular and network mechanisms underlying such a subcortical control of absence seizures remain unknown. The GABAergic projections from substantia nigra pars reticulata (SNR) to thalamocortical neurons of the ventral medial (VM) thalamic nucleus provide a potent network for the control of absence seizures by basal ganglia. The present in vivo study provides the first description of the activity of VM thalamic neurons during seizures in the genetic absence epilepsy rats from Strasbourg, a well established model of absence epilepsy. Cortical paroxysms were accompanied in VM thalamic neurons by rhythmic bursts of action potentials. Pharmacological blockade of excitatory inputs of nigrothalamic neurons led to a transient interruption of SWDs, correlated with a change in the activity of thalamic cells, which was increased in frequency and converted into a sustained arrhythmic firing pattern. Simultaneously, cortical neurons exhibited a decrease in their firing rate that was associated with an increase in membrane polarization and a decrease in input resistance. These new findings demonstrate that an inhibition of SNR neurons changes the activity of their thalamic targets, which in turn could affect cortical neurons excitability and, consequently, the generation of cortical epileptic discharges. Thus, the nigro-thalamo-cortical pathway may provide an on-line system control of absence seizures.
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Affiliation(s)
- Jeanne Tamar Paz
- Institut National de la Santé et de la Recherche Médicale, Unité 667, Collège de France, F-75231 Paris, France.
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Rossetti F, Rodrigues MCA, de Oliveira JAC, Garcia-Cairasco N. EEG wavelet analyses of the striatum–substantia nigra pars reticulata–superior colliculus circuitry: Audiogenic seizures and anticonvulsant drug administration in Wistar audiogenic rats (War strain). Epilepsy Res 2006; 72:192-208. [PMID: 17150334 DOI: 10.1016/j.eplepsyres.2006.08.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2005] [Revised: 08/04/2006] [Accepted: 08/14/2006] [Indexed: 01/15/2023]
Abstract
The importance of the substantia nigra pars reticulata (SNPr), striatum (STR) and superior colicullus (SC) in the blockade of experimental seizures is well known. But, in audiogenic seizures (brainstem tonic-clonic seizures), the anticonvulsant activity of these nuclei is still controversial. In the present study we aimed to analyze the STR-SNPr-CS circuitry in the audiogenic seizures of Wistar audiogenic rat (WAR). Behavioral and electroencephalographic (EEG) data were collected from WARs under no treatment or injection with systemic (phenobarbital) or intracerebral (intranigral) drugs (muscimol and phenobarbital). The main EEG frequency oscillation of STR, SNPr and SC seen before, during and after audiogenic seizures or during seizure protection, was determinated with wavelet spectral analyses. This method allows the association between behavior and EEG (video-EEG). Audiogenic seizures last only for half a minute in average, suggesting that the interruptions of seizures are probably not due to exhaustion. Systemic phenobarbital caused an acute and dose-dependent behavioral and EEGraphic anticonvulsant effect both in WARs. The dose of phenobarbital 15mg/kg protected animals almost completely, without side effects such as ataxia and sedation. In our data, this endogenous "natural" seizure blockade (or termination) seems to be similar to the "forced" seizure abolition, like the one caused by a systemic non-ataxic phenobarbital dose, because in both cases an intense decrease in the EEG main frequency oscillation can be seen in SNPr and SC. Intranigral phenobarbital or muscimol did not protect animals, and actually induced an increase in the main EEG frequency oscillation in SC. The main finding of the present study is that, in contrast to what is well believed about the incapacity to control audiogenic seizures by the striato-nigro-tectal circuitry, we collected here evidences that these nuclei are involved in the ability to block these seizures. However, the striato-nigro-tectal circuitry in WARs, a genetically developed strain, seems to have different functional mechanisms when compared with normal rats.
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Affiliation(s)
- Franco Rossetti
- Physiology Department, Ribeirão Preto School of Medicine, University of São Paulo, Avenida Bandeirantes 3900, 14049-900 Ribeirão Preto, São Paulo, Brazil
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Velísek L, Velísková J, Giorgi FS, Moshé SL. Sex-specific control of flurothyl-induced tonic-clonic seizures by the substantia nigra pars reticulata during development. Exp Neurol 2006; 201:203-11. [PMID: 16730708 DOI: 10.1016/j.expneurol.2006.04.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2006] [Revised: 03/14/2006] [Accepted: 04/01/2006] [Indexed: 01/13/2023]
Abstract
The substantia nigra pars reticulata (SNR) plays an important age- and sex-specific role in control of clonic seizures. Its involvement in control of tonic-clonic seizures is contradictory. We investigated the role of the SNR in the tonic-clonic seizures induced in male, female and neonatally castrated male rats using flurothyl. In adult female rats, vaginal impedance determined the changes in progesterone/estrogen ratio. Rats at various postnatal ages received infusions of muscimol or vehicle in the SNRanterior or SNRposterior. Furthermore, in 15-day-old (P15) and adult male rats, ZAPA (a GABA(A) receptor agonist) or AP7 (an NMDA receptor antagonist) was infused. The developmental profile of tonic-clonic seizure threshold differed between male and female rats possibly due to early postnatal testosterone surge in male rats. On the other hand, changing estrogen/progesterone ratio in cycling adult female rats had no effect on seizure threshold. Intranigral muscimol had proconvulsant effects on tonic-clonic seizures only in immature rats, and this effect was dependent on the perinatal testosterone surge. ZAPA had anticonvulsant effects in P15 rats but was not effective in adult rats. Only AP7 had anticonvulsant effects in both adult and P15 rats. Results indicate that thresholds for flurothyl-induced tonic-clonic seizures develop under the control of postnatal testosterone. Although GABAergic inhibition in the SNR affects tonic-clonic seizures in developing rats, only the NMDA antagonist had consistent anticonvulsant effects throughout development.
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Affiliation(s)
- Libor Velísek
- Department of Neurology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
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Blandini F, Armentero MT, Tassorelli C, Greco R, Fancellu R, Bramanti P, Nappi G, Martignoni E. Selective lesion of the substantia nigra pars reticulata reduces the cortical Fos expression induced by stimulation of striatal D1-like receptors, in the rat. Exp Neurol 2006; 200:240-4. [PMID: 16516888 DOI: 10.1016/j.expneurol.2006.01.024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2005] [Revised: 01/13/2006] [Accepted: 01/25/2006] [Indexed: 11/21/2022]
Abstract
We investigated the effects of a selective lesion of the substantia nigra pars reticulata (SNr), obtained by stereotaxic injection of ibotenic acid, on the cortical expression of Fos protein induced by striatal infusion of dopamine, D1-like agonist SKF 38393, in Sprague-Dawley rats. The specific aim was to clarify the role of the basal ganglia output structures - SNr in particular - in the cortical activation that follows a D1-dependent activation of the striatofugal, direct pathway, in freely moving animals. The striatal, unilateral infusion of 30 mM SKF 38393 induced consistent Fos expression throughout the whole ipsilateral cerebral cortex, including motor, sensorimotor, associative, and limbic areas; such expression was dramatically reduced by excitotoxic lesion of the ipsilateral SNr. These findings confirm the prominent role of the SNr in the transmission of striatofugal signals to functionally different cortical areas.
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Affiliation(s)
- F Blandini
- Laboratory of Functional Neurochemistry, IRCCS Neurological Institute C. Mondino, Via Mondino 2, 27100 Pavia, Italy.
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Fedotova IB, Kostyna ZA, Poletaeva II, Kolpakov VG, Barykina NN, Axenovich TI. Genetic Analysis of the Predisposition to Audiogenic Seizure Fits in Krushinsky-Molodkina Rat Strain. RUSS J GENET+ 2005. [DOI: 10.1007/s11177-005-0223-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Merker B. The liabilities of mobility: a selection pressure for the transition to consciousness in animal evolution. Conscious Cogn 2005; 14:89-114. [PMID: 15766892 DOI: 10.1016/s1053-8100(03)00002-3] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2002] [Indexed: 11/22/2022]
Abstract
The issue of the biological origin of consciousness is linked to that of its function. One source of evidence in this regard is the contrast between the types of information that are and are not included within its compass. Consciousness presents us with a stable arena for our actions-the world-but excludes awareness of the multiple sensory and sensorimotor transformations through which the image of that world is extracted from the confounding influence of self-produced motion of multiple receptor arrays mounted on multijointed and swivelling body parts. Likewise excluded are the complex orchestrations of thousands of muscle movements routinely involved in the pursuit of our goals. This suggests that consciousness arose as a solution to problems in the logistics of decision making in mobile animals with centralized brains, and has correspondingly ancient roots.
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Affiliation(s)
- Bjorn Merker
- Department of Psychology, Uppsala University, SE-75142, Sweden.
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Vinogradova LV, Kuznetsova GD, Shatskova AB, van Rijn CM. Vigabatrin in Low Doses Selectively Suppresses the Clonic Component of Audiogenically Kindled Seizures in Rats. Epilepsia 2005; 46:800-10. [PMID: 15946321 DOI: 10.1111/j.1528-1167.2005.52604.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
PURPOSE The effect of systemic administration of the gamma-aminobutyric acid (GABA)-transaminase inhibitor vigabatrin (VGB) on different components of convulsions was tested in the model of audiogenically kindled seizures, which consist of brainstem (running, tonus) and forebrain (clonus) elements. METHODS Audiogenically susceptible rats of Krushinsky-Molodkina (KM), Wistar, and WAG/Rij strains received repeated sound stimulation (60 dB, 10-80 kHz) until kindled audiogenic seizures were reliably elicited. Kindled audiogenic seizures consisted of running, tonic, and generalized clonic phases in KM rats (severe audiogenic seizures) and of running and Racine stage 5 facial/forelimb clonus in Wistar and WAG/Rij rats (moderate seizures). Vehicle, 100, or 200 mg/kg of VGB was intraperitoneally injected 2, 4 and 24 h before the induction of kindled audiogenic seizures. RESULTS At both doses, VGB did not change the seizure latency and the duration of running and tonic convulsions, but suppressed clonic ones in all rat strains. In KM rats, the mean duration of posttonic clonus was significantly reduced at 24 h after 100 mg/kg and from 4 h after 200 mg/kg. In Wistar and WAG/Rij rats, the mean duration of facial/forelimb clonus was reduced from 4 and 2 h after 100- and 200-mg/kg administration, respectively; 24 h after the high-dose injection, clonus was completely blocked in all rats of both strains. No difference in efficacy of VGB between Wistar and WAG/Rij rats was observed. CONCLUSIONS VGB more effectively suppresses clonic convulsions than running and tonic ones in audiogenically kindled rats. It is supposed that this selective anticonvulsive effect of VGB results from different sensitivities of forebrain and brainstem epileptic networks to the presumed GABA enhancement.
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MESH Headings
- Acoustic Stimulation
- Animals
- Anticonvulsants/administration & dosage
- Anticonvulsants/pharmacology
- Anticonvulsants/therapeutic use
- Behavior, Animal/drug effects
- Behavior, Animal/physiology
- Disease Models, Animal
- Dose-Response Relationship, Drug
- Epilepsy, Reflex/diagnosis
- Epilepsy, Reflex/prevention & control
- Female
- Injections, Intraperitoneal
- Kindling, Neurologic/drug effects
- Kindling, Neurologic/physiology
- Male
- Motor Activity/drug effects
- Motor Activity/physiology
- Rats
- Rats, Inbred Strains
- Rats, Wistar
- Seizures/prevention & control
- Severity of Illness Index
- Species Specificity
- Vigabatrin/administration & dosage
- Vigabatrin/pharmacology
- Vigabatrin/therapeutic use
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Affiliation(s)
- Ludmilla V Vinogradova
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia
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Paz JT, Deniau JM, Charpier S. Rhythmic bursting in the cortico-subthalamo-pallidal network during spontaneous genetically determined spike and wave discharges. J Neurosci 2005; 25:2092-101. [PMID: 15728849 PMCID: PMC6726056 DOI: 10.1523/jneurosci.4689-04.2005] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2004] [Revised: 01/07/2005] [Accepted: 01/08/2005] [Indexed: 11/21/2022] Open
Abstract
Absence seizures are characterized by impairment of consciousness associated with bilaterally synchronous spike-and-wave discharges (SWDs) in the electroencephalogram (EEG), which reflect paroxysmal oscillations in thalamocortical networks. Although recent studies suggest that the subthalamic nucleus (STN) provides an endogenous control system that influences the occurrence of absence seizures, the mechanisms of propagation of cortical epileptic discharges in the STN have never been explored. The present study provides the first description of the electrophysiological activity in the cortico-subthalamo-pallidal network during absence seizures in the genetic absence epilepsy rats from Strasbourg, a well established model of absence epilepsy. In corticosubthalamic neurons, the SWDs were associated with repetitive suprathreshold depolarizations correlated with EEG spikes. These cortical paroxysms were reflected in the STN by synchronized, rhythmic, high-frequency bursts of action potentials. Intracellular recordings revealed that the intraburst pattern in STN neurons was sculpted by an early depolarizing synaptic potential, followed by a short hyperpolarization and a rebound of excitation. The rhythmic hyperpolarizations in STN neurons during SWDs likely originate from a subpopulation of pallidal neurons exhibiting rhythmic bursting temporally correlated with the EEG spikes. The repetitive discharges in STN neurons accompanying absence seizures might convey powerful excitation to basal ganglia output nuclei and, consequently, may participate in the control of thalamocortical SWDs.
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Affiliation(s)
- Jeanne Tamar Paz
- Institut National de la Santé et de la Recherche Médicale U114, Chaire de Neuropharmacologie, Collège de France and U667, 75231 Paris Cedex 05, France.
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Slaght SJ, Paz T, Chavez M, Deniau JM, Mahon S, Charpier S. On the activity of the corticostriatal networks during spike-and-wave discharges in a genetic model of absence epilepsy. J Neurosci 2005; 24:6816-25. [PMID: 15282287 PMCID: PMC6729718 DOI: 10.1523/jneurosci.1449-04.2004] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Absence seizures are characterized by impairment of consciousness associated with widespread bilaterally synchronous spike-and-wave discharges (SWDs) in the electroencephalogram (EEG), which reflect highly synchronized oscillations in thalamocortical networks. Although recent pharmacological studies suggest that the basal ganglia could provide a remote control system for absence seizures, the mechanisms of propagation of epileptic discharges in these subcortical nuclei remain unknown. In the present study, we provide the first description of the electrical events in the corticostriatal pathway during spontaneous SWDs in the genetic absence epilepsy rats from Strasbourg (GAERS), a genetic model of absence epilepsy. In corticostriatal neurons, the SWDs were associated with suprathreshold rhythmic depolarizations in-phase with local EEG spikes. Consistent with this synchronized firing in their excitatory cortical afferents, striatal output neurons (SONs) exhibited, during SWDs, large-amplitude rhythmic synaptic depolarizations. However, SONs did not discharge during SWDs. Instead, the rhythmic synaptic excitation of SONs was shunted by a Cl(-)-dependent increase in membrane conductance that was temporally correlated with bursts of action potentials in striatal GABAergic interneurons. The reduced SON excitability accompanying absence seizures may participate in the control of SWDs by affecting the flow of cortical information within the basal ganglia circuits.
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Affiliation(s)
- Seán J Slaght
- Institut National de la Santé et de la Recherche Médicale U114, Chaire de Neuropharmacologie, Collège de France, 75231 Paris Cedex 05, France
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Molinari F, Raas-Rothschild A, Rio M, Fiermonte G, Encha-Razavi F, Palmieri L, Palmieri F, Ben-Neriah Z, Kadhom N, Vekemans M, Attié-Bitach T, Munnich A, Rustin P, Colleaux L. Impaired mitochondrial glutamate transport in autosomal recessive neonatal myoclonic epilepsy. Am J Hum Genet 2005; 76:334-9. [PMID: 15592994 PMCID: PMC1196378 DOI: 10.1086/427564] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2004] [Accepted: 11/17/2004] [Indexed: 11/03/2022] Open
Abstract
Severe neonatal epilepsies with suppression-burst pattern are epileptic syndromes with either neonatal onset or onset during the first months of life. These disorders are characterized by a typical electroencephalogram pattern--namely, suppression burst, in which higher-voltage bursts of slow waves mixed with multifocal spikes alternate with isoelectric suppression phases. Here, we report the genetic mapping of an autosomal recessive form of this condition to chromosome 11p15.5 and the identification of a missense mutation (p.Pro206Leu) in the gene encoding one of the two mitochondrial glutamate/H(+) symporters (SLC25A22, also known as "GC1"). The mutation cosegregated with the disease and altered a highly conserved amino acid. Functional analyses showed that glutamate oxidation in cultured skin fibroblasts from patients was strongly defective. Further studies in reconstituted proteoliposomes showed defective [(14)C]glutamate uniport and [(14)C]glutamate/glutamate exchange by mutant protein. Moreover, expression studies showed that, during human development, SLC25A22 is specifically expressed in the brain, within territories proposed to contribute to the genesis and control of myoclonic seizures. These findings provide the first direct molecular link between glutamate mitochondrial metabolism and myoclonic epilepsy and suggest potential insights into the pathophysiological bases of severe neonatal epilepsies with suppression-burst pattern.
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Affiliation(s)
- Florence Molinari
- INSERM U393, Hôpital Necker-Enfants Malades, Paris; Department of Human Genetics, Hadassah Hebrew University Medical Center, Jerusalem; and Department of Pharmaco-Biology, Laboratory of Biochemistry and Molecular Biology, University of Bari, and Consiglio Nazionale delle Richerche (CNR) Institute of Biomembranes and Bioenergetics, Bari, Italy
| | - Annick Raas-Rothschild
- INSERM U393, Hôpital Necker-Enfants Malades, Paris; Department of Human Genetics, Hadassah Hebrew University Medical Center, Jerusalem; and Department of Pharmaco-Biology, Laboratory of Biochemistry and Molecular Biology, University of Bari, and Consiglio Nazionale delle Richerche (CNR) Institute of Biomembranes and Bioenergetics, Bari, Italy
| | - Marlène Rio
- INSERM U393, Hôpital Necker-Enfants Malades, Paris; Department of Human Genetics, Hadassah Hebrew University Medical Center, Jerusalem; and Department of Pharmaco-Biology, Laboratory of Biochemistry and Molecular Biology, University of Bari, and Consiglio Nazionale delle Richerche (CNR) Institute of Biomembranes and Bioenergetics, Bari, Italy
| | - Giuseppe Fiermonte
- INSERM U393, Hôpital Necker-Enfants Malades, Paris; Department of Human Genetics, Hadassah Hebrew University Medical Center, Jerusalem; and Department of Pharmaco-Biology, Laboratory of Biochemistry and Molecular Biology, University of Bari, and Consiglio Nazionale delle Richerche (CNR) Institute of Biomembranes and Bioenergetics, Bari, Italy
| | - Ferechté Encha-Razavi
- INSERM U393, Hôpital Necker-Enfants Malades, Paris; Department of Human Genetics, Hadassah Hebrew University Medical Center, Jerusalem; and Department of Pharmaco-Biology, Laboratory of Biochemistry and Molecular Biology, University of Bari, and Consiglio Nazionale delle Richerche (CNR) Institute of Biomembranes and Bioenergetics, Bari, Italy
| | - Luigi Palmieri
- INSERM U393, Hôpital Necker-Enfants Malades, Paris; Department of Human Genetics, Hadassah Hebrew University Medical Center, Jerusalem; and Department of Pharmaco-Biology, Laboratory of Biochemistry and Molecular Biology, University of Bari, and Consiglio Nazionale delle Richerche (CNR) Institute of Biomembranes and Bioenergetics, Bari, Italy
| | - Ferdinando Palmieri
- INSERM U393, Hôpital Necker-Enfants Malades, Paris; Department of Human Genetics, Hadassah Hebrew University Medical Center, Jerusalem; and Department of Pharmaco-Biology, Laboratory of Biochemistry and Molecular Biology, University of Bari, and Consiglio Nazionale delle Richerche (CNR) Institute of Biomembranes and Bioenergetics, Bari, Italy
| | - Ziva Ben-Neriah
- INSERM U393, Hôpital Necker-Enfants Malades, Paris; Department of Human Genetics, Hadassah Hebrew University Medical Center, Jerusalem; and Department of Pharmaco-Biology, Laboratory of Biochemistry and Molecular Biology, University of Bari, and Consiglio Nazionale delle Richerche (CNR) Institute of Biomembranes and Bioenergetics, Bari, Italy
| | - Noman Kadhom
- INSERM U393, Hôpital Necker-Enfants Malades, Paris; Department of Human Genetics, Hadassah Hebrew University Medical Center, Jerusalem; and Department of Pharmaco-Biology, Laboratory of Biochemistry and Molecular Biology, University of Bari, and Consiglio Nazionale delle Richerche (CNR) Institute of Biomembranes and Bioenergetics, Bari, Italy
| | - Michel Vekemans
- INSERM U393, Hôpital Necker-Enfants Malades, Paris; Department of Human Genetics, Hadassah Hebrew University Medical Center, Jerusalem; and Department of Pharmaco-Biology, Laboratory of Biochemistry and Molecular Biology, University of Bari, and Consiglio Nazionale delle Richerche (CNR) Institute of Biomembranes and Bioenergetics, Bari, Italy
| | - Tania Attié-Bitach
- INSERM U393, Hôpital Necker-Enfants Malades, Paris; Department of Human Genetics, Hadassah Hebrew University Medical Center, Jerusalem; and Department of Pharmaco-Biology, Laboratory of Biochemistry and Molecular Biology, University of Bari, and Consiglio Nazionale delle Richerche (CNR) Institute of Biomembranes and Bioenergetics, Bari, Italy
| | - Arnold Munnich
- INSERM U393, Hôpital Necker-Enfants Malades, Paris; Department of Human Genetics, Hadassah Hebrew University Medical Center, Jerusalem; and Department of Pharmaco-Biology, Laboratory of Biochemistry and Molecular Biology, University of Bari, and Consiglio Nazionale delle Richerche (CNR) Institute of Biomembranes and Bioenergetics, Bari, Italy
| | - Pierre Rustin
- INSERM U393, Hôpital Necker-Enfants Malades, Paris; Department of Human Genetics, Hadassah Hebrew University Medical Center, Jerusalem; and Department of Pharmaco-Biology, Laboratory of Biochemistry and Molecular Biology, University of Bari, and Consiglio Nazionale delle Richerche (CNR) Institute of Biomembranes and Bioenergetics, Bari, Italy
| | - Laurence Colleaux
- INSERM U393, Hôpital Necker-Enfants Malades, Paris; Department of Human Genetics, Hadassah Hebrew University Medical Center, Jerusalem; and Department of Pharmaco-Biology, Laboratory of Biochemistry and Molecular Biology, University of Bari, and Consiglio Nazionale delle Richerche (CNR) Institute of Biomembranes and Bioenergetics, Bari, Italy
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Mussi-Ribeiro A, Miranda A, Gobbo-Netto L, Peporine Lopes N, dos Santos WF. A anticonvulsive fraction from Scaptocosa raptoria (Araneae: Lycosidae) spider venom. Neurosci Lett 2004; 371:171-5. [PMID: 15519751 DOI: 10.1016/j.neulet.2004.08.064] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2004] [Revised: 08/24/2004] [Accepted: 08/27/2004] [Indexed: 11/24/2022]
Abstract
Several spider neurotoxins are known to show highly selective effects on nervous tissues. Intracerebral injection into rats of spider venom from Scaptocosa raptoria, prevents seizures induced by convulsant agents. Injection of phenytoin (390 pmol/200 nl), muscimol (90 pmol/200 nl), baclofen (500 pmol/200 nl) into the substantia nigra (SN) pars reticulata, protected rats from convulsions evoked by unilateral focal injection of bicuculline into the area tempestas by 50, 80, and 100%, respectively. Denatured S. raptoria crude venom (4.6 microg, 2.3 microg, and 920 ng/200 nl), when administered into the SN, prevented seizures elicited by bicuculline in the area tempestas by 100, 100, and 87.5%, respectively. The injection into the SN of 160 ng/200 nl of fraction SrTx1 isolated from S. raptoria venom, reduced the magnitude of seizures. This fraction was rechromatographed affording fractions SrTx1.1, SrTx1.2 and SrTx1.3, and they were administered into the SN at doses of 100, 200, and 400 ng/200 nl respectively. Fraction SrTx1.3 protected 50, 85.7, and 100% of the animals against the seizures elicited by bicuculline injected into the area tempestas. This suggests that S. raptoria venom as well as its SrTx1.3 fraction, might be potential sources of new anticonvulsant drugs.
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Affiliation(s)
- Alessandra Mussi-Ribeiro
- Neurobiology and Venoms Laboratory, Department of Biology, Faculty of Philosophy, Sciences and Literature of Ribeirão Preto, University of Sao Paulo, Sao Paulo SP 14040-901, Brazil
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Faingold CL. Emergent properties of CNS neuronal networks as targets for pharmacology: application to anticonvulsant drug action. Prog Neurobiol 2004; 72:55-85. [PMID: 15019176 DOI: 10.1016/j.pneurobio.2003.11.003] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2003] [Accepted: 11/19/2003] [Indexed: 01/13/2023]
Abstract
CNS drugs may act by modifying the emergent properties of complex CNS neuronal networks. Emergent properties are network characteristics that are not predictably based on properties of individual member neurons. Neuronal membership within networks is controlled by several mechanisms, including burst firing, gap junctions, endogenous and exogenous neuroactive substances, extracellular ions, temperature, interneuron activity, astrocytic integration and external stimuli. The effects of many CNS drugs in vivo may critically involve actions on specific brain loci, but this selectivity may be absent when the same neurons are isolated from the network in vitro where emergent properties are lost. Audiogenic seizures (AGS) qualify as an emergent CNS property, since in AGS the acoustic stimulus evokes a non-linear output (motor convulsion), but the identical stimulus evokes minimal behavioral changes normally. The hierarchical neuronal network, subserving AGS in rodents is initiated in inferior colliculus (IC) and progresses to deep layers of superior colliculus (DLSC), pontine reticular formation (PRF) and periaqueductal gray (PAG) in genetic and ethanol withdrawal-induced AGS. In blocking AGS, certain anticonvulsants reduce IC neuronal firing, while other agents act primarily on neurons in other AGS network sites. However, the NMDA receptor channel blocker, MK-801, does not depress neuronal firing in any network site despite potently blocking AGS. Recent findings indicate that MK-801 actually enhances firing in substantia nigra reticulata (SNR) neurons in vivo but not in vitro. Thus, the MK-801-induced firing increases in SNR neurons observed in vivo may involve an indirect effect via disinhibition, involving an action on the emergent properties of this seizure network.
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Affiliation(s)
- Carl L Faingold
- Department of Pharmacology, Southern Illinois University School of Medicine, P.O. Box 19629, Springfield, IL 62794-9629, USA.
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43
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Goodman JH. Brain Stimulation As a Therapy for Epilepsy. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2004; 548:239-47. [PMID: 15250598 DOI: 10.1007/978-1-4757-6376-8_17] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
The failure of current antiepileptic therapies to adequately treat a significant number of epileptic patients highlights the need for the development of new treatments for the disorder. A new strategy that is currently being developed is to deliver electrical stimulation directly to the brain to decrease or prevent seizure activity. Clinical evidence that electrical stimulation could interfere with seizure activity was initially reported in the 1930's. However, many of these early studies consisted of case reports or were poorly controlled. In addition, there were a number of studies that failed to observe any beneficial effect of brain stimulation on seizures. More recently, deep brain stimulation has been used successfully to treat patients with movement disorders and vagus nerve stimulation has been shown to effectively decrease seizure activity in a select population of epilepsy patients. These advances have led to a reexamination of the potential therapeutic benefits of deep brain stimulation for the treatment of epilepsy. There is now experimental and clinical evidence that direct electrical stimulation of the brain can prevent or decrease seizure activity. However, several fundamental questions remain to be resolved. They include where in the brain the stimulus should be delivered and what type of stimulation would be most effective. One goal of this research is to combine the beneficial aspects of electrical stimulation with seizure detection technology in an implantable responsive stimulator. The device will detect the onset of a seizure and deliver an electrical stimulus that will safely block seizure activity without interfering with normal brain function.
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Affiliation(s)
- Jeffrey H Goodman
- Center for Neual Recovery and Rehabilitation Research, Helen Hayes Hospital, New York State Department of Health, West Havenstraw, USA
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Salas R, Orr-Urtreger A, Broide RS, Beaudet A, Paylor R, De Biasi M. The nicotinic acetylcholine receptor subunit alpha 5 mediates short-term effects of nicotine in vivo. Mol Pharmacol 2003; 63:1059-66. [PMID: 12695534 DOI: 10.1124/mol.63.5.1059] [Citation(s) in RCA: 166] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Nicotine, acting at pentameric neuronal nicotinic acetylcholine receptors (nAChRs), is the primary addictive component in tobacco. At low doses, it affects attention, learning, memory, anxiety, cardiovascular responses, thermoregulation, and nociception. At high doses, nicotine produces more drastic behaviors and eventually induces tonic-clonic seizures in rodents. In mammals, several subunits of the nAChRs have been cloned, including eight alpha and three beta subunits. To study the physiological role of the alpha 5 subunit, we have generated alpha 5-deficient mice. These mice have a generally healthy appearance and are normal in a standard battery of behavioral tests. However, the sensitivity of alpha 5 mutant mice to nicotine-induced behaviors and seizures is dramatically reduced compared with their wild-type littermates. These animals have a normal brain anatomy and normal levels of mRNA for other nAChR subunits, namely alpha 4, alpha 6, alpha 7, beta 2, and beta 4. In addition, (125)I-epibatidine and [(125)I]alpha-bungarotoxin binding in the brains of alpha 5-deficient mice is normal. Together, these results suggest a direct involvement of the alpha 5 subunit in the observed phenotypes.
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Affiliation(s)
- Ramiro Salas
- Division of Neuroscience, Baylor College of Medicine, Houston, Texas 77030, USA
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45
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Lado FA, Velísek L, Moshé SL. The effect of electrical stimulation of the subthalamic nucleus on seizures is frequency dependent. Epilepsia 2003; 44:157-64. [PMID: 12558568 DOI: 10.1046/j.1528-1157.2003.33802.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE Animal studies and anecdotal human case reports have indicated that the subthalamic nucleus (STN) may be a site of anticonvulsant action. METHODS We tested the hypothesis that continuous electrical stimulation of the STN inhibits seizures acutely. We determined the effects of three stimulation frequencies, 130 Hz, 260 Hz, and 800 Hz, on generalized clonic and tonic-clonic flurothyl seizures. Adult male rats were implanted with concentric bipolar stimulating electrodes in the STN bilaterally. After recovery, rats underwent flurothyl seizures to compare the effects of each stimulation frequency on seizure threshold. Rats were tested 4 times, twice in the stimulated condition, and twice in the unstimulated condition. The order of trials was random, except that stimulation trials alternated with control trials. Flurothyl seizure thresholds under each stimulation condition were compared with control values from the same animal. RESULTS Bilateral stimulation of the STN at 130 Hz produced a significant increase in the seizure threshold for clonic flurothyl seizures, whereas stimulation at 260 Hz did not appear to have any effect on seizures. STN stimulation at 800 Hz significantly lowered seizure threshold for tonic-clonic seizures. CONCLUSIONS We conclude that electrical stimulation of the STN can be anticonvulsant, but the effects appear to depend on the stimulation frequency and the type of seizure.
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Affiliation(s)
- Fred A Lado
- Department of Neurology, Comprehensive Epilepsy Management Center, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, New York 10461, U.S.A.
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Nail-Boucherie K, Lê-Pham BT, Marescaux C, Depaulis A. Suppression of absence seizures by electrical and pharmacological activation of the caudal superior colliculus in a genetic model of absence epilepsy in the rat. Exp Neurol 2002; 177:503-14. [PMID: 12429195 DOI: 10.1006/exnr.2002.7997] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Activation of the superior colliculus has been shown to reproduce the antiepileptic effect of the inhibition of the substantia nigra reticulata. A circuit involving neurons of the caudal deep layers of the superior colliculus has been suggested to control brain stem convulsive seizures. The present study was designed to examine whether a similar circuit is also involved in the control of absence seizures. For this, activation of either the rostral or caudal parts of the deep and intermediate layers of the superior colliculus was applied in a genetic model of absence seizures in the rat (GAERS). Single-shock (5 s) electrical stimulation of the rostral and caudal superior colliculus interrupted ongoing spike-and-wave discharges at an intensity (antiepileptic threshold) significantly lower than the intensity inducing behavioral effects. At this intensity, no interruption of licking behavior was observed in water-deprived rats. Repeated stimulations (5 s on/5 s off) at the antiepileptic threshold reduced absence seizures only during the first 10 min. Bilateral microinjection of a GABA antagonist (picrotoxin, 33 pmol/side) significantly suppressed spike-and-wave discharges when applied in the caudal aspect of the superior colliculus. This antiepileptic effect appears dissociated from an anxiogenic effect, as tested in an elevated plus maze test. Finally, bilateral injection of picrotoxin (33 pmol/side) appeared more effective in the superficial and intermediate layers of the caudal superior colliculus, whereas such injections had only weak effects on absence seizures when applied in the deep layers. These results suggest that a specific population of neurons located in the intermediate and superficial layers of the caudal superior colliculus is involved in the inhibitory control of absence seizures. It may constitute an important relay for the control of absence seizures by the basal ganglia via the substantia nigra reticulata.
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Affiliation(s)
- K Nail-Boucherie
- Neurobiologie et Neuropharmacologie des Epilepsies Généralisées, INSERM U. 398, Faculté de Médecine, Strasbourg, France
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Garcia-Cairasco N. A critical review on the participation of inferior colliculus in acoustic-motor and acoustic-limbic networks involved in the expression of acute and kindled audiogenic seizures. Hear Res 2002; 168:208-22. [PMID: 12117522 DOI: 10.1016/s0378-5955(02)00371-4] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The main goal of this article is to review the key role that the inferior colliculus plays in the expression of acoustic-motor and acoustic-limbic integration involved, respectively, in acute and chronic audiogenic seizures. In order to put this in context, we will review the behavioral characterization of acute and chronic audiogenic seizures, neuroanatomical substrates, neurochemistry, neuropharmacology, electrophysiology, as well as the cellular and molecular mechanisms involved in their expression. Secondly, we will also correlate our results, collected from audiogenic seizures susceptible rats, before and after the genetic selection of our own audiogenic susceptible strain, and from those sensitized by lesions or drug microinjections, with those pertinent from the international literature. In brief, genetic or sensitized animals express acute audiogenic seizures as a wild running behavior preceding the onset of tonic-clonic seizures. The latter can have several presentations including opistotonus and fore- and hindlimb tonic hyperextensions, followed by clonic convulsions of fore- and hindlimbs. Chronic (kindled) audiogenic seizures change this behavioral expression, with similar patterns such as those present in temporal lobe epileptic seizures, intermingled with the original audiogenic seizure pattern, which is known to be dependent on brainstem networks.
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Affiliation(s)
- Norberto Garcia-Cairasco
- Neurophysiology and Experimental Neuroethology Laboratory, Physiology Department, Ribeirão Preto School of Medicine, University of São Paulo, 14049-900 SP, Ribeirão Preto, Brazil.
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Abstract
Like normal cerebral function, epileptic seizures involve widespread network interactions between cortical and subcortical structures. Although the cortex is often emphasized as the site of seizure origin, accumulating evidence points to a crucial role for subcortical structures in behavioral manifestations, propagation, and, in some cases, initiation of epileptic seizures. Extensive previous studies have shown the importance of subcortical structures in animal seizure models, but corresponding human studies have been relatively few. We review the existing evidence supporting the importance of the thalamus, basal ganglia, hypothalamus, cerebellum, and brain stem in human epilepsy. We also propose a "network inhibition hypothesis" through which focal cortical seizures disrupt function in subcortical structures (such as the medial diencephalon and pontomesencephalic reticular formation), leading secondarily to widespread inhibition of nonseizing cortical regions, which may in turn be responsible for behavioral manifestations such as loss of consciousness during complex partial seizures.
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Affiliation(s)
- Andrew D. Norden
- Departments of Neurology and Neurobiology, Yale University School of Medicine, 333 Cedar Street, New Haven, 06520-8018, CT, USA
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