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Tran H, Mahzoum RE, Bonnot A, Cohen I. Epileptic seizure clustering and accumulation at transition from activity to rest in GAERS rats. Front Neurol 2024; 14:1296421. [PMID: 38328755 PMCID: PMC10847272 DOI: 10.3389/fneur.2023.1296421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Accepted: 12/14/2023] [Indexed: 02/09/2024] Open
Abstract
Knowing when seizures occur may help patients and can also provide insight into epileptogenesis mechanisms. We recorded seizures over periods of several days in the Genetic Absence Epileptic Rat from Strasbourg (GAERS) model of absence epilepsy, while we monitored behavioral activity with a combined head accelerometer (ACCEL), neck electromyogram (EMG), and electrooculogram (EOG). The three markers consistently discriminated between states of behavioral activity and rest. Both GAERS and control Wistar rats spent more time in rest (55-66%) than in activity (34-45%), yet GAERS showed prolonged continuous episodes of activity (23 vs. 18 min) and rest (34 vs. 30 min). On average, seizures lasted 13 s and were separated by 3.2 min. Isolated seizures were associated with a decrease in the power of the activity markers from steep for ACCEL to moderate for EMG and weak for EOG, with ACCEL and EMG power changes starting before seizure onset. Seizures tended to occur in bursts, with the probability of seizing significantly increasing around a seizure in a window of ±4 min. Furthermore, the seizure rate was strongly increased for several minutes when transitioning from activity to rest. These results point to mechanisms that control behavioral states as determining factors of seizure occurrence.
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Anwar MS, Frolov N, Hramov AE, Ghosh D. Self-organized bistability on globally coupled higher-order networks. Phys Rev E 2024; 109:014225. [PMID: 38366474 DOI: 10.1103/physreve.109.014225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 01/04/2024] [Indexed: 02/18/2024]
Abstract
Self-organized bistability (SOB) stands as a critical behavior for the systems delicately adjusting themselves to the brink of bistability, characterized by a first-order transition. Its essence lies in the inherent ability of the system to undergo enduring shifts between the coexisting states, achieved through the self-regulation of a controlling parameter. Recently, SOB has been established in a scale-free network as a recurrent transition to a short-living state of global synchronization. Here, we embark on a theoretical exploration that extends the boundaries of the SOB concept on a higher-order network (implicitly embedded microscopically within a simplicial complex) while considering the limitations imposed by coupling constraints. By applying Ott-Antonsen dimensionality reduction in the thermodynamic limit to the higher-order network, we derive SOB requirements under coupling limits that are in good agreement with numerical simulations on systems of finite size. We use continuous synchronization diagrams and statistical data from spontaneous synchronized events to demonstrate the crucial role SOB plays in initiating and terminating temporary synchronized events. We show that under weak-coupling consumption, these spontaneous occurrences closely resemble the statistical traits of the epileptic brain functioning.
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Affiliation(s)
- Md Sayeed Anwar
- Physics and Applied Mathematics Unit, Indian Statistical Institute, 203 B. T. Road, Kolkata 700108, India
| | - Nikita Frolov
- Laboratory of Dynamics in Biological Systems, Department of Cellular and Molecular Medicine, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - Alexander E Hramov
- Baltic Center for Neurotechnology and Artificial Intelligence, Immanuel Kant Baltic Federal University, 14, A. Nevskogo str., Kaliningrad 236016, Russia
| | - Dibakar Ghosh
- Physics and Applied Mathematics Unit, Indian Statistical Institute, 203 B. T. Road, Kolkata 700108, India
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3
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Han RT, Vainchtein ID, Schlachetzki JC, Cho FS, Dorman LC, Ahn E, Kim DK, Barron JJ, Nakao-Inoue H, Molofsky AB, Glass CK, Paz JT, Molofsky AV. Microglial pattern recognition via IL-33 promotes synaptic refinement in developing corticothalamic circuits in mice. J Exp Med 2023; 220:e20220605. [PMID: 36520518 PMCID: PMC9757845 DOI: 10.1084/jem.20220605] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 09/21/2022] [Accepted: 11/28/2022] [Indexed: 12/23/2022] Open
Abstract
Microglia are critical regulators of brain development that engulf synaptic proteins during postnatal synapse remodeling. However, the mechanisms through which microglia sense the brain environment are not well defined. Here, we characterized the regulatory program downstream of interleukin-33 (IL-33), a cytokine that promotes microglial synapse remodeling. Exposing the developing brain to a supraphysiological dose of IL-33 altered the microglial enhancer landscape and increased binding of stimulus-dependent transcription factors including AP-1/FOS. This induced a gene expression program enriched for the expression of pattern recognition receptors, including the scavenger receptor MARCO. CNS-specific deletion of IL-33 led to increased excitatory/inhibitory synaptic balance, spontaneous absence-like epileptiform activity in juvenile mice, and increased seizure susceptibility in response to chemoconvulsants. We found that MARCO promoted synapse engulfment, and Marco-deficient animals had excess thalamic excitatory synapses and increased seizure susceptibility. Taken together, these data define coordinated epigenetic and functional changes in microglia and uncover pattern recognition receptors as potential regulators of postnatal synaptic refinement.
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Affiliation(s)
- Rafael T. Han
- Departments of Psychiatry and Behavioral Sciences/Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
| | - Ilia D. Vainchtein
- Departments of Psychiatry and Behavioral Sciences/Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
| | | | - Frances S. Cho
- Neuroscience Graduate Program, University of California, San Francisco, San Francisco, CA, USA
- Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
- Gladstone Institute of Neurological Disease, San Francisco, CA, USA
| | - Leah C. Dorman
- Departments of Psychiatry and Behavioral Sciences/Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
- Neuroscience Graduate Program, University of California, San Francisco, San Francisco, CA, USA
| | - Eunji Ahn
- Departments of Psychiatry and Behavioral Sciences/Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
| | - Dong Kyu Kim
- Departments of Psychiatry and Behavioral Sciences/Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
| | - Jerika J. Barron
- Departments of Psychiatry and Behavioral Sciences/Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
| | - Hiromi Nakao-Inoue
- Departments of Psychiatry and Behavioral Sciences/Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
| | - Ari B. Molofsky
- Department of Laboratory Medicine, University of California, San Francisco, San Francisco, CA, USA
| | - Christopher K. Glass
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Jeanne T. Paz
- Neuroscience Graduate Program, University of California, San Francisco, San Francisco, CA, USA
- Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
- Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, CA, USA
- Gladstone Institute of Neurological Disease, San Francisco, CA, USA
| | - Anna V. Molofsky
- Departments of Psychiatry and Behavioral Sciences/Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
- Neuroscience Graduate Program, University of California, San Francisco, San Francisco, CA, USA
- Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, CA, USA
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4
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Dudarenko MV, Pozdnyakova NG. Perinatal hypoxia and thalamus brain region: increased efficiency of antiepileptic drug levetiracetam to inhibit GABA release from nerve terminals. UKRAINIAN BIOCHEMICAL JOURNAL 2022. [DOI: 10.15407/ubj94.05.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Levetiracetam (LV), 2S-(2-oxo-1-pyrrolidiny1) butanamide, is an antiepileptic drug. The exact mechanisms of anticonvulsant effects of LV remain unclear. In this study, rats (Wistar strain) underwent hypoxia and seizures at the age of 10–12 postnatal days (pd). [3H]GABA release was analysed in isolated from thalamus nerve terminals (synaptosomes) during development at the age of pd 17–19 and pd 24–26 (infantile stage), pd 38–40 (puberty) and pd 66–73 (young adults) in control and after perinatal hypoxia. The extracellular level of [3H]GABA in the preparation of thalamic synaptosomes increased during development at the age of pd 38–40 and pd 66–73 as compared to earlier ones. LV did not influence the extracellular level of [3H]GABA in control and after perinatal hypoxia at all studied ages. Exocytotic [3H]GABA release in control increased at the age of pd 24–26 as compared to pd 17–19. After hypoxia, exocytotic [3H]GABA release from synaptosomes also increased during development. LV elevated [3H]GABA release from thalamic synaptosomes at the age of pd 66–73 after hypoxia and during blockage of GABA uptake by NO-711 only. LV realizes its antiepileptic effects at the presynaptic site through an increase in exocytotic release of [3H]GABA in thalamic synaptosomes after perinatal hypoxia at pd 66–73. LV exhibited a more significant effect in thalamic synaptosomes after perinatal hypoxia than in control ones. The action of LV is age-dependent, and the drug was inert at the infantile stage that can be useful for an LV application strategy in child epilepsy therapy. Keywords: brain development, exocytosis, GABA, levetiracetam, perinatal hypoxia, thalamic synaptosomes
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Shakeshaft A, Laiou P, Abela E, Stavropoulos I, Richardson MP, Pal DK, Howell A, Hyde A, McQueen A, Duran A, Gaurav A, Collingwood A, Kitching A, Shakeshaft A, Papathanasiou A, Clough A, Gribbin A, Swain A, Needle A, Hall A, Smith A, Macleod A, Chhibda A, Fonferko-Shadrach B, Camara B, Petrova B, Stuart C, Hamilton C, Peacey C, Campbell C, Cotter C, Edwards C, Picton C, Busby C, Quamina C, Waite C, West C, Ng CC, Giavasi C, Backhouse C, Holliday C, Mewies C, Thow C, Egginton D, Dickerson D, Rice D, Mullan D, Daly D, Mcaleer D, Gardella E, Stephen E, Irvine E, Sacre E, Lin F, Castle G, Mackay G, Salim H, Cock H, Collier H, Cockerill H, Navarra H, Mhandu H, Crudgington H, Hayes I, Stavropoulos I, Daglish J, Smith J, Bartholomew J, Cotta J, Ceballos JP, Natarajan J, Crooks J, Quirk J, Bland J, Sidebottom J, Gesche J, Glenton J, Henry J, Davis J, Ball J, Selmer KK, Rhodes K, Holroyd K, Lim KS, O’Brien K, Thrasyvoulou L, Makawa L, Charles L, Richardson L, Nelson L, Walding L, Woodhead L, Ehiorobo L, Hawkins L, Adams L, Connon M, Home M, Baker M, Mencias M, Richardson MP, Sargent M, Syvertsen M, Milner M, Recto M, Chang M, O'Donoghue M, Young M, Ray M, Panjwani N, Ghaus N, Sudarsan N, Said N, Pickrell O, Easton P, Frattaroli P, McAlinden P, Harrison R, Swingler R, Wane R, Ramsay R, Møller RS, McDowall R, Clegg R, Uka S, White S, Truscott S, Francis S, Tittensor S, Sharman SJ, Chung SK, Patel S, Ellawela S, Begum S, Kempson S, Raj S, Bayley S, Warriner S, Kilroy S, MacFarlane S, Brown T, Samakomva T, Nortcliffe T, Calder V, Collins V, Parker V, Richmond V, Stern W, Haslam Z, Šobíšková Z, Agrawal A, Whiting A, Pratico A, Desurkar A, Saraswatula A, MacDonald B, Fong CY, Beier CP, Andrade D, Pauldhas D, Greenberg DA, Deekollu D, Pal DK, Jayachandran D, Lozsadi D, Galizia E, Scott F, Rubboli G, Angus-Leppan H, Talvik I, Takon I, Zarubova J, Koht J, Aram J, Lanyon K, Irwin K, Hamandi K, Yeung L, Strug LJ, Rees M, Reuber M, Kirkpatrick M, Taylor M, Maguire M, Koutroumanidis M, Khan M, Moran N, Striano P, Bala P, Bharat R, Pandey R, Mohanraj R, Thomas R, Belderbos R, Slaght SJ, Delamont S, Sastry S, Mariguddi S, Kumar S, Kumar S, Majeed T, Jegathasan U, Whitehouse W. Heterogeneity of resting-state EEG features in juvenile myoclonic epilepsy and controls. Brain Commun 2022; 4:fcac180. [PMID: 35873918 PMCID: PMC9301584 DOI: 10.1093/braincomms/fcac180] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 05/18/2022] [Accepted: 07/07/2022] [Indexed: 11/12/2022] Open
Abstract
Abnormal EEG features are a hallmark of epilepsy, and abnormal frequency and network features are apparent in EEGs from people with idiopathic generalized epilepsy in both ictal and interictal states. Here, we characterize differences in the resting-state EEG of individuals with juvenile myoclonic epilepsy and assess factors influencing the heterogeneity of EEG features. We collected EEG data from 147 participants with juvenile myoclonic epilepsy through the Biology of Juvenile Myoclonic Epilepsy study. Ninety-five control EEGs were acquired from two independent studies [Chowdhury et al. (2014) and EU-AIMS Longitudinal European Autism Project]. We extracted frequency and functional network-based features from 10 to 20 s epochs of resting-state EEG, including relative power spectral density, peak alpha frequency, network topology measures and brain network ictogenicity: a computational measure of the propensity of networks to generate seizure dynamics. We tested for differences between epilepsy and control EEGs using univariate, multivariable and receiver operating curve analysis. In addition, we explored the heterogeneity of EEG features within and between cohorts by testing for associations with potentially influential factors such as age, sex, epoch length and time, as well as testing for associations with clinical phenotypes including anti-seizure medication, and seizure characteristics in the epilepsy cohort. P-values were corrected for multiple comparisons. Univariate analysis showed significant differences in power spectral density in delta (2-5 Hz) (P = 0.0007, hedges' g = 0.55) and low-alpha (6-9 Hz) (P = 2.9 × 10-8, g = 0.80) frequency bands, peak alpha frequency (P = 0.000007, g = 0.66), functional network mean degree (P = 0.0006, g = 0.48) and brain network ictogenicity (P = 0.00006, g = 0.56) between epilepsy and controls. Since age (P = 0.009) and epoch length (P = 1.7 × 10-8) differed between the two groups and were potential confounders, we controlled for these covariates in multivariable analysis where disparities in EEG features between epilepsy and controls remained. Receiver operating curve analysis showed low-alpha power spectral density was optimal at distinguishing epilepsy from controls, with an area under the curve of 0.72. Lower average normalized clustering coefficient and shorter average normalized path length were associated with poorer seizure control in epilepsy patients. To conclude, individuals with juvenile myoclonic epilepsy have increased power of neural oscillatory activity at low-alpha frequencies, and increased brain network ictogenicity compared with controls, supporting evidence from studies in other epilepsies with considerable external validity. In addition, the impact of confounders on different frequency-based and network-based EEG features observed in this study highlights the need for careful consideration and control of these factors in future EEG research in idiopathic generalized epilepsy particularly for their use as biomarkers.
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Affiliation(s)
- Amy Shakeshaft
- Department of Basic & Clinical Neuroscience, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, UK,MRC Centre for Neurodevelopmental Disorders, King’s College London, London, UK
| | - Petroula Laiou
- Department of Biostatistics and Health Informatics, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, UK
| | - Eugenio Abela
- Department of Basic & Clinical Neuroscience, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, UK
| | | | - Mark P Richardson
- Correspondence may also be addressed to: Professor Mark P Richardson Maurice Wohl Clinical Neurosciences Institute Institute of Psychiatry, Psychology & Neuroscience King’s College London, 5 Cutcombe Road, London SE5 9RX, UK E-mail:
| | - Deb K Pal
- Correspondence to: Professor Deb K Pal Maurice Wohl Clinical Neurosciences Institute Institute of Psychiatry, Psychology & Neuroscience King’s College London 5 Cutcombe Road, London SE5 9RX, UK E-mail:
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Antoine MW. Paradoxical Hyperexcitability in Disorders of Neurodevelopment. Front Mol Neurosci 2022; 15:826679. [PMID: 35571370 PMCID: PMC9102973 DOI: 10.3389/fnmol.2022.826679] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 03/14/2022] [Indexed: 01/29/2023] Open
Abstract
Autism Spectrum Disorder (ASD), Rett syndrome (RTT) and Angelman Syndrome (AS) are neurodevelopmental disorders (NDDs) that share several clinical characteristics, including displays of repetitive movements, developmental delays, language deficits, intellectual disability, and increased susceptibility to epilepsy. While several reviews address the biological basis of non-seizure-related ASD phenotypes, here, I highlight some shared biological mechanisms that may contribute to increased seizure susceptibility. I focus on genetic studies identifying the anatomical origin of the seizure phenotype in loss-of-function, monogenic, mouse models of these NDDs, combined with insights gained from complementary studies quantifying levels of synaptic excitation and inhibition. Epilepsy is characterized by a sudden, abnormal increase in synchronous activity within neuronal networks, that is posited to arise from excess excitation, largely driven by reduced synaptic inhibition. Primarily for this reason, elevated network excitability is proposed to underlie the causal basis for the ASD, RTT, and AS phenotypes. Although, mouse models of these disorders replicate aspects of the human condition, i.e., hyperexcitability discharges or seizures on cortical electroencephalograms, measures at the synaptic level often reveal deficits in excitatory synaptic transmission, rather than too much excitation. Resolving this apparent paradox has direct implications regarding expected outcomes of manipulating GABAergic tone. In particular, in NDDs associated with seizures, cortical circuits can display reduced, rather than normal or increased levels of synaptic excitation, and therefore suggested treatments aimed at increasing inhibition could further promote hypoactivity instead of normality. In this review, I highlight shared mechanisms across animal models for ASD, RTT, and AS with reduced synaptic excitation that nevertheless promote hyperexcitability in cortical circuits.
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Affiliation(s)
- Michelle W. Antoine
- Section on Neural Circuits, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, United States
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Ilbay G, Balıkcı A, Köktürk S, Yılmaz MY, Ates N, Baydemır C, Balcı S. Neonatal Tactile Stimulation Downregulates Dendritic Spines in Layer V Pyramidal Neurons of the WAG/Rij Rat Somatosensory Cortex. Neural Plast 2022; 2022:7251460. [PMID: 35465396 PMCID: PMC9019463 DOI: 10.1155/2022/7251460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 02/28/2022] [Accepted: 03/25/2022] [Indexed: 11/18/2022] Open
Abstract
Objective The aim of our study is to examine the effects of neonatal tactile stimulations on the brain structures that previously defined as the focus of epilepsy in the Wistar-Albino-Glaxo from Rijswijk (WAG/Rij) rat brain with genetic absence epilepsy. Methods In the present research, morphology and density of dendritic spines were analyzed in layer V pyramidal neurons of the somatosensory cortex (SoCx) of WAG/Rij rats (nonstimulated control, tactile-stimulated, and maternal separated rats) and healthy Wistar (nonepileptic) rats. To achieve this, a Golgi-Cox method was used. Results Dendritic spine number in layer V of the SoCx has been detected significantly higher in adult WAG/Rij rats at postnatal day 150 in comparison to nonepileptic adult control Wistar rats (p < 0.001). Moreover, quantitative analyses of dendrite structure in adult WAG/Rij rats showed a decrease in dendrite spine density of pyramidal neurons of SoCx which occurred in early neonatal exposure to maternal separation (MS) and tactile stimulation (TS) (p < 0.001). Conclusions Our findings provide the first evidence that tactile stimulations during the early postnatal period have a long-term impact on dendrite structure in WAG/Rij rat's brain and demonstrate that neonatal tactile stimulation can regulate dendritic spines in layer V in pyramidal neurons of SoCx in epileptic brains.
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Affiliation(s)
- Gul Ilbay
- Department of Physiology, Kocaeli University, School of Medicine, Kocaeli, Turkey
| | - Aymen Balıkcı
- Department of Physiology, Kocaeli University, School of Medicine, Kocaeli, Turkey
| | - Sibel Köktürk
- Department of Histology and Embryology, Istanbul University, Istanbul Medical Faculty, Istanbul, Turkey
| | - Melda Yardımoglu Yılmaz
- Department of Histology and Embryology, Kocaeli University, School of Medicine, Kocaeli, Turkey
| | - Nurbay Ates
- Department of Physiology, Kocaeli University, School of Medicine, Kocaeli, Turkey
| | - Canan Baydemır
- Department of Biostatistics and Medical Informatics, Kocaeli University, School of Medicine, Kocaeli, Turkey
| | - Sibel Balcı
- Department of Biostatistics and Medical Informatics, Kocaeli University, School of Medicine, Kocaeli, Turkey
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Sun L, Liu R, Yang H, Yu T, Wu J, Wang Q. Characteristics of Epileptiform Spike-wave Discharges and Chronic Histopathology in Controlled Cortical Impact Model of Sprague-Dawley Rats. Neurochem Res 2022; 47:3615-3626. [PMID: 35103912 DOI: 10.1007/s11064-022-03542-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Revised: 01/17/2022] [Accepted: 01/24/2022] [Indexed: 10/19/2022]
Abstract
Post-traumatic epilepsy (PTE) is a serious complication that can occur following traumatic brain injury (TBI). Sustained secondary changes after TBI promote the process of PTE. Here, we aim to evaluate changes in behavior, electrocorticogram, and histomorphology in rats following chronic TBI models. We observed intensive 7-8 Hz spike-wave-discharges (SWDs) at frontal recording sites and quantified them in SD rats with different degrees of TBI and compared them with age-matched sham rats to evaluate the association between SWDs and injury severity. Notably, although SWDs were even presented in the sham group, the number and duration of events were much lower than those in the TBI groups. SWDs have numerous similarities to absence seizures, such as abrupt onset, termination, and lack of postictal suppression, which may be the nonconvulsive characteristics of PTE. Retigabine, a novel antiepileptic drug, is ineffective in reducing SWDs. In addition, we examined chronic histopathological changes in TBI rats. Rats subjected to moderate and severe TBI exhibited significantly impaired neurological function, which was accompanied by marked cortical injury, hippocampus deformation, reactive gliosis, and mossy fiber sprouting. Long-term progressive structural changes in the brain are one of the characteristics of epileptogenesis after TBI. Our study provided the potential value of epileptiform SWDs in reflecting the nonconvulsive characteristic of PTE and highlighted the vital role of chronic pathological changes, such as reactive gliosis, in promoting the epileptogenesis following TBI.
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Affiliation(s)
- Lei Sun
- Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070, China.,Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, 100070, China.,China National Clinical Research Center for Neurological Diseases, Beijing, 100070, China
| | - Ru Liu
- Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070, China.,Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, 100070, China.,China National Clinical Research Center for Neurological Diseases, Beijing, 100070, China
| | - Huajun Yang
- Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, 100070, China.,Beijing Friendship Hospital, Capital Medical University, Beijing, 100050, China
| | - Tingting Yu
- Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070, China.,Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, 100070, China.,China National Clinical Research Center for Neurological Diseases, Beijing, 100070, China
| | - Jianping Wu
- Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070, China. .,Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, 100070, China. .,China National Clinical Research Center for Neurological Diseases, Beijing, 100070, China. .,School of Chemistry, Chemical Engineering and Life Sciences, Wuhan University of Technology, Wuhan, 430070, China.
| | - Qun Wang
- Beijing Tiantan Hospital, Capital Medical University, Beijing, 100070, China. .,China National Clinical Research Center for Neurological Diseases, Beijing, 100070, China. .,Beijing Institute for Brain Disorders, Beijing, 100069, China.
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9
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Tsvetaeva DA, Raevsky VV. Responses of Somatosensory Cortical Neurons to Stimulation of the Vibrissal Area in WAG/Rij Rats Genetically Predisposed to Absence Epilepsy. J EVOL BIOCHEM PHYS+ 2021. [DOI: 10.1134/s0022093021050197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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10
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Gobbo D, Scheller A, Kirchhoff F. From Physiology to Pathology of Cortico-Thalamo-Cortical Oscillations: Astroglia as a Target for Further Research. Front Neurol 2021; 12:661408. [PMID: 34177766 PMCID: PMC8219957 DOI: 10.3389/fneur.2021.661408] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 05/11/2021] [Indexed: 12/21/2022] Open
Abstract
The electrographic hallmark of childhood absence epilepsy (CAE) and other idiopathic forms of epilepsy are 2.5-4 Hz spike and wave discharges (SWDs) originating from abnormal electrical oscillations of the cortico-thalamo-cortical network. SWDs are generally associated with sudden and brief non-convulsive epileptic events mostly generating impairment of consciousness and correlating with attention and learning as well as cognitive deficits. To date, SWDs are known to arise from locally restricted imbalances of excitation and inhibition in the deep layers of the primary somatosensory cortex. SWDs propagate to the mostly GABAergic nucleus reticularis thalami (NRT) and the somatosensory thalamic nuclei that project back to the cortex, leading to the typical generalized spike and wave oscillations. Given their shared anatomical basis, SWDs have been originally considered the pathological transition of 11-16 Hz bursts of neural oscillatory activity (the so-called sleep spindles) occurring during Non-Rapid Eye Movement (NREM) sleep, but more recent research revealed fundamental functional differences between sleep spindles and SWDs, suggesting the latter could be more closely related to the slow (<1 Hz) oscillations alternating active (Up) and silent (Down) cortical activity and concomitantly occurring during NREM. Indeed, several lines of evidence support the fact that SWDs impair sleep architecture as well as sleep/wake cycles and sleep pressure, which, in turn, affect seizure circadian frequency and distribution. Given the accumulating evidence on the role of astroglia in the field of epilepsy in the modulation of excitation and inhibition in the brain as well as on the development of aberrant synchronous network activity, we aim at pointing at putative contributions of astrocytes to the physiology of slow-wave sleep and to the pathology of SWDs. Particularly, we will address the astroglial functions known to be involved in the control of network excitability and synchronicity and so far mainly addressed in the context of convulsive seizures, namely (i) interstitial fluid homeostasis, (ii) K+ clearance and neurotransmitter uptake from the extracellular space and the synaptic cleft, (iii) gap junction mechanical and functional coupling as well as hemichannel function, (iv) gliotransmission, (v) astroglial Ca2+ signaling and downstream effectors, (vi) reactive astrogliosis and cytokine release.
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Affiliation(s)
- Davide Gobbo
- Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, Germany
| | - Anja Scheller
- Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, Germany
| | - Frank Kirchhoff
- Molecular Physiology, Center for Integrative Physiology and Molecular Medicine (CIPMM), University of Saarland, Homburg, Germany
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11
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Frolov N, Hramov A. Extreme synchronization events in a Kuramoto model: The interplay between resource constraints and explosive transitions. CHAOS (WOODBURY, N.Y.) 2021; 31:063103. [PMID: 34241300 DOI: 10.1063/5.0055156] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 05/17/2021] [Indexed: 06/13/2023]
Abstract
Many living and artificial systems possess structural and dynamical properties of complex networks. One of the most exciting living networked systems is the brain, in which synchronization is an essential mechanism of its normal functioning. On the other hand, excessive synchronization in neural networks reflects undesired pathological activity, including various forms of epilepsy. In this context, network-theoretical approach and dynamical modeling may uncover deep insight into the origins of synchronization-related brain disorders. However, many models do not account for the resource consumption needed for the neural networks to synchronize. To fill this gap, we introduce a phenomenological Kuramoto model evolving under the excitability resource constraints. We demonstrate that the interplay between increased excitability and explosive synchronization induced by the hierarchical organization of the network forces the system to generate short-living extreme synchronization events, which are well-known signs of epileptic brain activity. Finally, we establish that the network units occupying the medium levels of hierarchy most strongly contribute to the birth of extreme events emphasizing the focal nature of their origin.
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Affiliation(s)
- Nikita Frolov
- Neuroscience and Cognitive Technology Laboratory, Center for Technologies in Robotics and Mechatronics Components, Innopolis University, 420500 Innopolis, The Republic of Tatarstan, Russia
| | - Alexander Hramov
- Neuroscience and Cognitive Technology Laboratory, Center for Technologies in Robotics and Mechatronics Components, Innopolis University, 420500 Innopolis, The Republic of Tatarstan, Russia
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12
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Panthi S, Leitch B. Chemogenetic Activation of Feed-Forward Inhibitory Parvalbumin-Expressing Interneurons in the Cortico-Thalamocortical Network During Absence Seizures. Front Cell Neurosci 2021; 15:688905. [PMID: 34122016 PMCID: PMC8193234 DOI: 10.3389/fncel.2021.688905] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 05/04/2021] [Indexed: 12/11/2022] Open
Abstract
Parvalbumin-expressing (PV+) interneurons are a subset of GABAergic inhibitory interneurons that mediate feed-forward inhibition (FFI) within the cortico-thalamocortical (CTC) network of the brain. The CTC network is a reciprocal loop with connections between cortex and thalamus. FFI PV+ interneurons control the firing of principal excitatory neurons within the CTC network and prevent runaway excitation. Studies have shown that generalized spike-wave discharges (SWDs), the hallmark of absence seizures on electroencephalogram (EEG), originate within the CTC network. In the stargazer mouse model of absence epilepsy, reduced FFI is believed to contribute to absence seizure genesis as there is a specific loss of excitatory α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) at synaptic inputs to PV+ interneurons within the CTC network. However, the degree to which this deficit is directly related to seizure generation has not yet been established. Using chemogenetics and in vivo EEG recording, we recently demonstrated that functional silencing of PV+ interneurons in either the somatosensory cortex (SScortex) or the reticular thalamic nucleus (RTN) is sufficient to generate absence-SWDs. Here, we used the same approach to assess whether activating PV+ FFI interneurons within the CTC network during absence seizures would prevent or reduce seizures. To target these interneurons, mice expressing Cre recombinase in PV+ interneurons (PV-Cre) were bred with mice expressing excitatory Gq-DREADD (hM3Dq-flox) receptors. An intraperitoneal dose of pro-epileptic chemical pentylenetetrazol (PTZ) was used to induce absence seizure. The impact of activation of FFI PV+ interneurons during seizures was tested by focal injection of the “designer drug” clozapine N-oxide (CNO) into either the SScortex or the RTN thalamus. Seizures were assessed in PVCre/Gq-DREADD animals using EEG/video recordings. Overall, DREADD-mediated activation of PV+ interneurons provided anti-epileptic effects against PTZ-induced seizures. CNO activation of FFI either prevented PTZ-induced absence seizures or suppressed their severity. Furthermore, PTZ-induced tonic-clonic seizures were also reduced in severity by activation of FFI PV+ interneurons. In contrast, administration of CNO to non-DREADD wild-type control animals did not afford any protection against PTZ-induced seizures. These data demonstrate that FFI PV+ interneurons within CTC microcircuits could be a potential therapeutic target for anti-absence seizure treatment in some patients.
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Affiliation(s)
- Sandesh Panthi
- Department of Anatomy, School of Biomedical Sciences, Brain Health Research Centre, University of Otago, Dunedin, New Zealand
| | - Beulah Leitch
- Department of Anatomy, School of Biomedical Sciences, Brain Health Research Centre, University of Otago, Dunedin, New Zealand
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13
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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: 94] [Impact Index Per Article: 23.5] [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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14
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Dynamical mesoscale model of absence seizures in genetic models. PLoS One 2020; 15:e0239125. [PMID: 32991590 PMCID: PMC7524004 DOI: 10.1371/journal.pone.0239125] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2020] [Accepted: 08/31/2020] [Indexed: 12/20/2022] Open
Abstract
A mesoscale network model is proposed for the development of spike and wave discharges (SWDs) in the cortico-thalamo-cortical (C-T-C) circuit. It is based on experimental findings in two genetic models of childhood absence epilepsy–rats of WAG/Rij and GAERS strains. The model is organized hierarchically into two levels (brain structures and individual neurons) and composed of compartments for representation of somatosensory cortex, reticular and ventroposteriomedial thalamic nuclei. The cortex and the two thalamic compartments contain excitatory and inhibitory connections between four populations of neurons. Two connected subnetworks both including relevant parts of a C-T-C network responsible for SWD generation are modelled: a smaller subnetwork for the focal area in which the SWD generation can take place, and a larger subnetwork for surrounding areas which can be only passively involved into SWDs, but which is mostly responsible for normal brain activity. This assumption allows modeling of both normal and SWD activity as a dynamical system (no noise is necessary), providing reproducibility of results and allowing future analysis by means of theory of dynamical system theories. The model is able to reproduce most time-frequency changes in EEG activity accompanying the transition from normal to epileptiform activity and back. Three different mechanisms of SWD initiation reported previously in experimental studies were successfully reproduced in the model. The model incorporates also a separate mechanism for the maintenance of SWDs based on coupling analysis from experimental data. Finally, the model reproduces the possibility to stop ongoing SWDs with high frequency electrical stimulation, as described in the literature.
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15
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Balikci A, Ilbay G, Ates N. Neonatal Tactile Stimulations Affect Genetic Generalized Epilepsy and Comorbid Depression-Like Behaviors. Front Behav Neurosci 2020; 14:132. [PMID: 32792925 PMCID: PMC7390910 DOI: 10.3389/fnbeh.2020.00132] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 07/02/2020] [Indexed: 12/18/2022] Open
Abstract
Recent studies suggest that development of absence epilepsy and comorbid depression might be prevented by increased maternal care of the offspring, in which tactile stimulation induced by licking/grooming and non-nutritive contact seem to be crucial. In this study, we aimed to evaluate the effect of neonatal tactile stimulations (NTS) on absence epilepsy and depression-like behaviors in adulthood. Wistar Albino Glaxo from Rijswijk (WAG/Rij) rat pups with a genetic predisposition to absence epilepsy were divided into tactile stimulation (TS) group, deep touch pressure (DTP) group, maternal separation (MS) group or control group. Between postnatal day 3 and 21, manipulations (TS, DTP, and MS) were carried out for 15 min and three times a day. Animals were submitted to locomotor activity, sucrose consumption test (SCT) and forced swimming test (FST) at five months of age. At the age of six months, the electroencephalogram (EEG) recordings were conducted in order to quantify the spike-wave discharges (SWDs), which is the hallmark of absence epilepsy. The TS and DTP groups showed less and shorter SWDs in later life in comparison to maternally separated and control rats. SWDs’ number and total duration were significantly reduced in TS and DTP groups whereas mean duration of SWDs was reduced only in DTP group (p < 0.05). TS and DTP also decreased depression-like behaviors measured by SCT and FST in adult animals. In the SCT, number of approaches was significantly higher in TS and DTP groups than the maternally separated and control rats. In the FST, while the immobility latency of TS and DTP groups was significantly higher, only TS group showed significantly decreased immobility and increased swimming time. The results showed that NTS decreases both the number and length of SWDs and the depression-like behaviors in WAG/Rij rats probably by increasing arousal level and causing alterations in the level of some neurotrophic factors as well as in functions of the neural plasticity in the developing rat’s brain.
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Affiliation(s)
- Aymen Balikci
- Department of Physiology, Faculty of Medicine, Kocaeli University, Kocaeli, Turkey
| | - Gul Ilbay
- Department of Physiology, Faculty of Medicine, Kocaeli University, Kocaeli, Turkey
| | - Nurbay Ates
- Department of Physiology, Faculty of Medicine, Kocaeli University, Kocaeli, Turkey
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16
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Smyk MK, van Luijtelaar G. Circadian Rhythms and Epilepsy: A Suitable Case for Absence Epilepsy. Front Neurol 2020; 11:245. [PMID: 32411068 PMCID: PMC7198737 DOI: 10.3389/fneur.2020.00245] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 03/13/2020] [Indexed: 11/16/2022] Open
Abstract
Many physiological processes such as sleep, hormonal secretion, or thermoregulation, are expressed as daily rhythms orchestrated by the circadian timing system. A powerful internal clock mechanism ensures proper synchronization of vital functions within an organism on the one hand, and between the organism and the external environment on the other. Some of the pathological processes developing in the brain and body are subjected to circadian modulation as well. Epilepsy is one of the conditions which symptoms often worsen at a very specific time of a day. Variation in peak occurrence depends on the syndrome and localization of the epileptic focus. Moreover, the timing of some types of seizures is closely related to the sleep-wake cycle, one of the most prominent circadian rhythms. This review focuses on childhood absence epilepsy (CAE), a genetic generalized epilepsy syndrome, in which both, the circadian and sleep influences play a significant role in manifestation of symptoms. Human and animal studies report rhythmical occurrence of spike-wave discharges (SWDs), an EEG hallmark of CAE. The endogenous nature of the SWDs rhythm has been confirmed experimentally in a genetic animal model of the disease, rats of the WAG/Rij strain. Well-known detrimental effects of circadian misalignment were demonstrated to impact the severity of ongoing epileptic activity. SWDs are vigilance-dependent in both humans and animal models, occurring most frequently during passive behavioral states and light slow-wave sleep. The relationship with the sleep-wake cycle seems to be bidirectional, while sleep shapes the rhythm of seizures, epileptic phenotype changes sleep architecture. Circadian factors and the sleep-wake states dependency have a potential as add-ons in seizures' forecasting. Stability of the rhythm of recurrent seizures in individual patients has been already used as a variable which refines existing algorithms for seizures' prediction. On the other hand, apart from successful pharmacological approach, circadian hygiene including sufficient sleep and avoidance of internal desynchronization or sleep loss, may be beneficial for patients with epilepsy in everyday management of seizures.
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Affiliation(s)
- Magdalena K Smyk
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, Netherlands
| | - Gilles van Luijtelaar
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, Netherlands
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17
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van Luijtelaar G, van Oijen G. Establishing Drug Effects on Electrocorticographic Activity in a Genetic Absence Epilepsy Model: Advances and Pitfalls. Front Pharmacol 2020; 11:395. [PMID: 32351383 PMCID: PMC7175742 DOI: 10.3389/fphar.2020.00395] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 03/16/2020] [Indexed: 12/18/2022] Open
Abstract
The genetic rat models such as rats of the WAG/Rij strain and GAERS were developed as models for generalized genetic epilepsy and in particular for childhood absence epilepsy. These animal models were described in the eighties of the previous century and both models have, among others, face, construct and predictive validity. Both models were and are currently used as models to predict the action of antiepileptic medication and other experimental treatments, to elucidate neurobiological mechanisms of spike-wave discharges and epileptogenesis. Although the electroencephalagram (EEG)/electrocorticogram (ECoG) is imperative for establishing absence seizures and to quantify the for absence epilepsy typical spike-wave discharges, monitoring the animals behavior is equally necessary. Here an overview is given regarding the design of drug evaluation studies, which animals to use, classical and new EEG variables, the monitoring and quantification of the behavior of the rats, some pitfalls regarding the interpretation of the data, and some developments in EEG technology.
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Affiliation(s)
| | - Gerard van Oijen
- Donders Centre for Cognition, Radboud University, Nijmegen, Netherlands
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18
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Glaba P, Latka M, Krause MJ, Kuryło M, Jernajczyk W, Walas W, West BJ. Changes in Interictal Pretreatment and Posttreatment EEG in Childhood Absence Epilepsy. Front Neurosci 2020; 14:196. [PMID: 32231515 PMCID: PMC7082231 DOI: 10.3389/fnins.2020.00196] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 02/24/2020] [Indexed: 01/09/2023] Open
Abstract
Spike and wave discharges (SWDs) are a characteristic manifestation of childhood absence epilepsy (CAE). It has long been believed that they unpredictably emerge from otherwise almost normal interictal EEG. Herein, we demonstrate that pretreatment closed-eyes theta and beta EEG wavelet powers of CAE patients (20 girls and 10 boys, mean age 7.4 ± 1.9 years) are much higher than those of age-matched healthy controls at multiple sites of the 10-20 system. For example, at the C4 site, we observed a 100 and 63% increase in power of theta and beta rhythms, respectively. We were able to compare the baseline and posttreatment wavelet power in 16 patients. Pharmacotherapy brought about a statistically significant decrease in delta and theta wavelet power in all the channels, e.g., for C4 the reduction was equal to 45% (delta) and 63% (theta). The less pronounced attenuation of posttreatment beta waves was observed in 13 channels (36% at C4 site). The beta and theta wavelet power were positively correlated with the percentage of time in seizure (defined as the ratio of the duration of all absences which patients experienced to the duration of recording) for majority of channels. We hypothesize that the increased theta and beta powers result from cortical hyperexcitability and propensity for epileptic spike generation, respectively. We argue that the distinct features of CAE wavelet power spectrum may be used to define an EEG biomarker which could be used for diagnosis and monitoring of patients.
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Affiliation(s)
- Pawel Glaba
- Department of Biomedical Engineering, Wrocław University of Science and Technology, Wrocław, Poland
| | - Miroslaw Latka
- Department of Biomedical Engineering, Wrocław University of Science and Technology, Wrocław, Poland
| | | | - Marta Kuryło
- Department of Pediatric Neurology, T. Marciniak Hospital, Wrocław, Poland
| | - Wojciech Jernajczyk
- Clinical Neurophysiology, Institute of Psychiatry and Neurology, Warszawa, Poland
| | - Wojciech Walas
- Neonatal and Pediatric Intensive Care Unit, University Hospital in Opole, Opole, Poland
| | - Bruce J West
- Mathematics and Information Science Directorate, Army Research Office, Durham, NC, United States
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Tsvetaeva DA, Sitnikova EY, Raevsky VV. Cortical Somatosensory Neurons in WAG/Rij Rats Transform Firing Evoked by Simulation of Posterior Thalamic Nucleus from Tonic to Phasic at Age of 6 Months. Bull Exp Biol Med 2019; 168:1-4. [PMID: 31741241 DOI: 10.1007/s10517-019-04632-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Indexed: 10/25/2022]
Abstract
Functional peculiarities of paralemniscal subdivision of the thalamocortical system were examined in normal Wistar and in WAG/Rij rats genetically prone to absence epilepsy. In 6-7-month-old WAG/Rij characterized by developed epileptic activity, the response of cortical somatosensory neurons to single electrical stimulation of the posterior thalamic nucleus was phasic, whereas in normal Wistar rats, similar reaction was tonic. The study views this phasic response as neural equivalent of spike-wave discharges known as typical EEG symptom of absence epilepsy.
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Affiliation(s)
- D A Tsvetaeva
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia
| | - E Yu Sitnikova
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia
| | - V V Raevsky
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia.
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20
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Frolov N, Maksimenko V, Lüttjohann A, Koronovskii A, Hramov A. Feed-forward artificial neural network provides data-driven inference of functional connectivity. CHAOS (WOODBURY, N.Y.) 2019; 29:091101. [PMID: 31575143 DOI: 10.1063/1.5117263] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Accepted: 08/10/2019] [Indexed: 06/10/2023]
Abstract
We propose a new model-free method based on the feed-forward artificial neuronal network for detecting functional connectivity in coupled systems. The developed method which does not require large computational costs and which is able to work with short data trials can be used for analysis and reconstruction of connectivity in experimental multichannel data of different nature. We test this approach on the chaotic Rössler system and demonstrate good agreement with the previous well-known results. Then, we use our method to predict functional connectivity thalamo-cortical network of epileptic brain based on ECoG data set of WAG/Rij rats with genetic predisposition to absence epilepsy. We show the emergence of functional interdependence between cortical layers and thalamic nuclei after epileptic discharge onset.
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Affiliation(s)
- Nikita Frolov
- Neuroscience and Cognitive Technology Laboratory, Center for Technologies in Robotics and Mechatronics Components, Innopolis University, 420500 Innopolis, The Republic of Tatarstan, Russia
| | - Vladimir Maksimenko
- Neuroscience and Cognitive Technology Laboratory, Center for Technologies in Robotics and Mechatronics Components, Innopolis University, 420500 Innopolis, The Republic of Tatarstan, Russia
| | - Annika Lüttjohann
- Institute of Physiology I, University of Münster, Münster 48149, Germany
| | - Alexey Koronovskii
- Faculty of Nonlinear Processes, Saratov State University, 410012 Saratov, Russia
| | - Alexander Hramov
- Neuroscience and Cognitive Technology Laboratory, Center for Technologies in Robotics and Mechatronics Components, Innopolis University, 420500 Innopolis, The Republic of Tatarstan, Russia
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21
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Yang DP, Robinson PA. Unified analysis of global and focal aspects of absence epilepsy via neural field theory of the corticothalamic system. Phys Rev E 2019; 100:032405. [PMID: 31639915 DOI: 10.1103/physreve.100.032405] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Indexed: 06/10/2023]
Abstract
Absence epilepsy is characterized by a sudden paroxysmal loss of consciousness accompanied by oscillatory activity propagating over many brain areas. Although primary generalized absence seizures are supported by the global corticothalamic system, converging experimental evidence supports a focal theory of absence epilepsy. Here a physiology-based corticothalamic model is investigated with spatial heterogeneity due to focal epilepsy to unify global and focal aspects of absence epilepsy. Numeric and analytic calculations are employed to investigate the emergent spatiotemporal dynamics as well as their underlying dynamical mechanisms. They can be categorized into three scenarios: suppressed epilepsy, focal seizures, or generalized seizures, as summarized from a phase diagram vs focal width and characteristic axon range. The corresponding temporal frequencies and spatial extents of cortical waves in generalized seizures and focal seizures agree well with experimental observations of global and focal aspects of absence epilepsy, respectively. The emergence of the spatiotemporal dynamics corresponding to focal seizures provides a biophysical explanation of the temporally higher frequency but spatially more localized cortical waves observed in genetic rat models that display characteristics of human absence epilepsy. Predictions are also presented for further experimental test.
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Affiliation(s)
- Dong-Ping Yang
- School of Physics, University of Sydney, New South Wales 2006, Australia and Center for Integrative Brain Function, University of Sydney, New South Wales 2006, Australia
| | - P A Robinson
- School of Physics, University of Sydney, New South Wales 2006, Australia and Center for Integrative Brain Function, University of Sydney, New South Wales 2006, Australia
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22
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Lee S, Hwang E, Lee M, Choi JH. Distinct Topographical Patterns of Spike-Wave Discharge in Transgenic and Pharmacologically Induced Absence Seizure Models. Exp Neurobiol 2019; 28:474-484. [PMID: 31495076 PMCID: PMC6751861 DOI: 10.5607/en.2019.28.4.474] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 06/18/2019] [Accepted: 07/29/2019] [Indexed: 01/21/2023] Open
Abstract
Absence seizures (AS) are generalized non-convulsive seizures characterized by a brief loss of consciousness and spike-and-wave discharges (SWD) in an electroencephalogram (EEG). A number of animal models have been developed to explain the mechanisms of AS, and thalamo-cortical networks are considered to be involved. However, the cortical foci have not been well described in mouse models of AS. This study aims to use a high density EEG in pathophysiologically different AS models to compare the spatiotemporal patterns of SWDs. We used two AS models: a pharmacologically induced model (gamma-hydroxybutyric acid, GHB model) and a transgenic model (phospholipase beta4 knock-out, PLCβ4 model). The occurrences of SWDs were confirmed by thalamic recordings. The topographical analysis of SWDs showed that the onset and propagation patterns were markedly distinguishable between the two models. In the PLCβ4 model, the foci were located within the somatosensory cortex followed by propagation to the frontal cortex, whereas in the GHB model, a majority of SWDs was initiated in the prefrontal cortex followed by propagation to the posterior cortex. In addition, in the GHB model, foci were also observed in other cortical areas. This observation indicates that different cortical networks are involved in the generation of SWDs across the two models.
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Affiliation(s)
- Soojung Lee
- Department of Oral Physiology, Faculty of Dentistry, Kyung Hee University, Seoul 02447, Korea
| | - Eunjin Hwang
- Center for Neuroscience, Korea Institute of Science and Technology, Seoul 02792, Korea
| | - Mina Lee
- Center for Neuroscience, Korea Institute of Science and Technology, Seoul 02792, Korea.,Department of Neuroscience, University of Science and Technology, Daejeon 34113, Korea
| | - Jee Hyun Choi
- Center for Neuroscience, Korea Institute of Science and Technology, Seoul 02792, Korea.,Department of Neuroscience, University of Science and Technology, Daejeon 34113, Korea
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23
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Ding L, Satish S, Zhou C, Gallagher MJ. Cortical activation in generalized seizures. Epilepsia 2019; 60:1932-1941. [PMID: 31368118 DOI: 10.1111/epi.16306] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 07/09/2019] [Accepted: 07/09/2019] [Indexed: 01/03/2023]
Abstract
OBJECTIVE Patients with generalized epilepsy exhibit different epileptiform events including asymptomatic interictal spikes (IS), absence seizures with spike-wave discharges (SWDs), and myoclonic seizures (MS). Our objective was to determine the spatiotemporal patterns of cortical activation in SWDs, IS, and MS in the Gabra1+/A322D juvenile myoclonic epilepsy mouse. METHODS We fabricated affordable, flexible high-density electroencephalography (HdEEG) arrays and recorded spontaneous SWD, IS, and MS with video/HdEEG. We determined differences among the events in amplitude spectral density (ASD) in the δ/θ/α/β/γ frequency bands at baseline (3.5-4.0 seconds before the first spike time, t0 ) and the prespike period (0.1-0.5 seconds before t0 ), and we elucidated the spatiotemporal activation during the t0 spike. RESULTS All three events had an increase in ASD between baseline and prespike in at least one frequency band. During prespike, MS had the largest δ-band ASD, but SWD had the greatest α/β/γ band ASD. For all three events, the ASD was largest in the anterior regions. The t0 spike voltage was also greatest in the anterior regions for all three events and IS and MS had larger voltages than SWD. From 7.5 to 17.5 msec after t0 , MS had greater voltage than IS and SWD, and maximal voltage was in the posterior parietal region. SIGNIFICANCE Changes in spectral density from baseline to prespike indicate that none of these generalized events are instantaneous or entirely unpredictable. Prominent engagement of anterior cortical regions during prespike and at t0 suggest that common anterior neural circuits participate in each event. Differences in prespike ASD signify that although the events may engage similar brain regions, they may arise from distinct proictal states with different neuronal activity or connectivity. Prolonged activation of the posterior parietal area in MS suggests that posterior circuits contribute to the myoclonic jerk. Together, these findings identify brain regions and processes that could be specifically targeted for further recording and modulation.
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Affiliation(s)
- Li Ding
- Department of Neurology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Sanjana Satish
- Department of Neurology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Chengwen Zhou
- Department of Neurology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Martin J Gallagher
- Department of Neurology, Vanderbilt University Medical Center, Nashville, Tennessee
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24
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Tangwiriyasakul C, Perani S, Centeno M, Yaakub SN, Abela E, Carmichael DW, Richardson MP. Dynamic brain network states in human generalized spike-wave discharges. Brain 2019; 141:2981-2994. [PMID: 30169608 PMCID: PMC6158757 DOI: 10.1093/brain/awy223] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Accepted: 07/15/2018] [Indexed: 12/21/2022] Open
Abstract
Generalized spike-wave discharges in idiopathic generalized epilepsy are conventionally assumed to have abrupt onset and offset. However, in rodent models, discharges emerge during a dynamic evolution of brain network states, extending several seconds before and after the discharge. In human idiopathic generalized epilepsy, simultaneous EEG and functional MRI shows cortical regions may be active before discharges, and network connectivity around discharges may not be normal. Here, in human idiopathic generalized epilepsy, we investigated whether generalized spike-wave discharges emerge during a dynamic evolution of brain network states. Using EEG-functional MRI, we studied 43 patients and 34 healthy control subjects. We obtained 95 discharges from 20 patients. We compared data from patients with discharges with data from patients without discharges and healthy controls. Changes in MRI (blood oxygenation level-dependent) signal amplitude in discharge epochs were observed only at and after EEG onset, involving a sequence of parietal and frontal cortical regions then thalamus (P < 0.01, across all regions and measurement time points). Examining MRI signal phase synchrony as a measure of functional connectivity between each pair of 90 brain regions, we found significant connections (P < 0.01, across all connections and measurement time points) involving frontal, parietal and occipital cortex during discharges, and for 20 s after EEG offset. This network prominent during discharges showed significantly low synchrony (below 99% confidence interval for synchrony in this network in non-discharge epochs in patients) from 16 s to 10 s before discharges, then ramped up steeply to a significantly high level of synchrony 2 s before discharge onset. Significant connections were seen in a sensorimotor network in the minute before discharge onset. This network also showed elevated synchrony in patients without discharges compared to healthy controls (P = 0.004). During 6 s prior to discharges, additional significant connections to this sensorimotor network were observed, involving prefrontal and precuneus regions. In healthy subjects, significant connections involved a posterior cortical network. In patients with discharges, this posterior network showed significantly low synchrony during the minute prior to discharge onset. In patients without discharges, this network showed the same level of synchrony as in healthy controls. Our findings suggest persistently high sensorimotor network synchrony, coupled with transiently (at least 1 min) low posterior network synchrony, may be a state predisposing to generalized spike-wave discharge onset. Our findings also show that EEG onset and associated MRI signal amplitude change is embedded in a considerably longer period of evolving brain network states before and after discharge events.
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Affiliation(s)
- Chayanin Tangwiriyasakul
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry Psychology and Neuroscience, King's College London, London, UK
| | - Suejen Perani
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry Psychology and Neuroscience, King's College London, London, UK.,Developmental Imaging and Biophysics Section, Developmental Neurosciences Program, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Maria Centeno
- Developmental Imaging and Biophysics Section, Developmental Neurosciences Program, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Siti Nurbaya Yaakub
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry Psychology and Neuroscience, King's College London, London, UK
| | - Eugenio Abela
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry Psychology and Neuroscience, King's College London, London, UK
| | - David W Carmichael
- Developmental Imaging and Biophysics Section, Developmental Neurosciences Program, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Mark P Richardson
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry Psychology and Neuroscience, King's College London, London, UK.,King's College Hospital, London, UK
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25
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Lüttjohann A, Pape HC. Regional specificity of cortico-thalamic coupling strength and directionality during waxing and waning of spike and wave discharges. Sci Rep 2019; 9:2100. [PMID: 30765744 PMCID: PMC6375974 DOI: 10.1038/s41598-018-37985-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Accepted: 12/14/2018] [Indexed: 11/24/2022] Open
Abstract
Spike-wave discharges (SWDs) on the EEG during absence epilepsy are waxing and waning stages of corticothalamic hypersynchrony. While the somatosensory cortex contains an epileptic focus, the role of thalamic nuclei in SWD generation is debated. Here we assess the contribution of distinct thalamic nuclei through multiple-site unit recordings in a genetic rat model of absence epilepsy and cross-correlation analysis, revealing coupling strength and directionality of neuronal activity at high temporal resolution. Corticothalamic coupling increased and decreased during waxing and waning of SWD, respectively. A cortical drive on either sensory or higher order thalamic nuclei distinguished between onset and offset of SWD, respectively. Intrathalamic coupling steadily increased during maintained SWD activity, peaked at SWD offset, and subsequently displayed a sharp decline to baseline. The peak in intrathalamic coupling coincided with a sharp increase in coupling strength between reticular thalamic nucleus and somatosensory cortex. This increased influence of the inhibitory reticular thalamic nucleus is suggested to serve as a break for SWD activity. Overall, the data extend the cortical focus theory of absence epilepsy by identifying a regionally specific cortical lead over distinct thalamic nuclei, particularly also during waning of generalized epileptic discharges, thereby revealing a potential window and location for intervention.
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Affiliation(s)
- Annika Lüttjohann
- Institute of Physiology I, Westfälische Wilhelms-Universität Münster, Münster, Germany.
| | - Hans-Christian Pape
- Institute of Physiology I, Westfälische Wilhelms-Universität Münster, Münster, Germany.
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26
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Ictal Source Locations and Cortico-Thalamic Connectivity in Childhood Absence Epilepsy: Associations with Treatment Response. Brain Topogr 2018; 32:178-191. [PMID: 30291582 DOI: 10.1007/s10548-018-0680-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 10/01/2018] [Indexed: 10/28/2022]
Abstract
Childhood absence epilepsy (CAE), the most common pediatric epilepsy syndrome, is usually treated with valproic acid (VPA) and lamotrigine (LTG) in China. This study aimed to investigate the ictal source locations and functional connectivity (FC) networks between the cortices and thalamus that are related to treatment response. Magnetoencephalography (MEG) data from 25 patients with CAE were recorded at 300 Hz and analyzed in 1-30 Hz frequency bands. Neuromagnetic sources were volumetrically scanned with accumulated source imaging. The FC networks between the cortices and thalamus were evaluated at the source level through a connectivity analysis. Treatment outcome was assessed after 36-66 months following MEG recording. The children with CAE were divided into LTG responder, LTG non-responder, VPA responder and VPA non-responder groups. The ictal source locations and cortico-thalamic FC networks were compared to the treatment response. The ictal source locations in the post-dorsal medial frontal cortex (post-DMFC, including the medial primary motor cortex and the supplementary sensorimotor area) were observed in all LTG non-responders but in all LTG responders. At 1-7 Hz, patients with fronto-thalamo-parietal/occipital (F-T-P/O) networks were older than those with fronto-thalamic (F-T) networks or other cortico-thalamic networks (p = 0.000). The duration of seizures in patients with F-T-P/O networks at 1-7 Hz was longer than that in patients with F-T networks or other cortico-thalamic networks (p = 0.001). The ictal post-DMFC source localizations suggest that children with CAE might experience initial LTG monotherapy failure. Moreover, the cortico-thalamo-cortical network is associated with age. Finally, the cortico-thalamo-cortical network consists of anterior and posterior cortices and might contribute to the maintenance of discharges.
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27
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Garibotto V, Wissmeyer M, Giavri Z, Goldstein R, Seimbille Y, Seeck M, Ratib O, Haller S, Picard F. Nicotinic receptor abnormalities as a biomarker in idiopathic generalized epilepsy. Eur J Nucl Med Mol Imaging 2018; 46:385-395. [PMID: 30269157 DOI: 10.1007/s00259-018-4175-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 09/18/2018] [Indexed: 02/07/2023]
Abstract
PURPOSE Mutations of cholinergic neuronal nicotinic receptors have been identified in the autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE), associated with changes on PET images using [18F]-F-85380-A (F-A-85380), an α4β2 nicotinic receptor ligand. The aim of the present study was to evaluate potential changes in nicotinic receptor availability in other types of epilepsy. METHODS We included 34 male participants, 12 patients with idiopathic generalized epilepsy (IGE), 10 with non-lesional diurnal focal epilepsy, and 12 age-matched healthy controls. All patients underwent PET/CT using F-A-85380 and [18F]-fluorodeoxyglucose (FDG), 3D T1 MRI and diffusion tensor imaging (DTI). F-A-85380 and FDG images were compared with the control group using a voxel-wise (SPM12) and a volumes of interest (VOI) analysis. RESULTS In the group of patients with IGE, the voxel-wise and VOI analyses showed a significant increase of F-A-85380 ratio index of binding potential (BPRI, corresponding to the receptor availability) in the anterior cingulate cortex (ACC), without structural changes on MRI. At an individual level, F-A-85380 BPRI increase in the ACC could distinguish IGE patients from controls and from patients with focal epilepsy with good accuracy. CONCLUSIONS We observed focal changes of density/availability of nicotinic receptors in IGE, namely an increase in the ACC. These data suggest that the modulation of α4β2 nicotinic receptors plays a role not only in ADNFLE, but also in other genetic epileptic syndromes such as IGE and could serve as a biomarker of epilepsy syndromes with a genetic background.
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Affiliation(s)
- Valentina Garibotto
- Nuclear Medicine and Molecular Imaging Division, Department of Medical Imaging, University Hospitals of Geneva, 4 rue Gabrielle-Perret-Gentil, 1211, Genève 14, Switzerland. .,Faculty of Medicine, Geneva University, 1211, Geneva, Switzerland.
| | - Michael Wissmeyer
- Nuclear Medicine and Molecular Imaging Division, Department of Medical Imaging, University Hospitals of Geneva, 4 rue Gabrielle-Perret-Gentil, 1211, Genève 14, Switzerland
| | - Zoi Giavri
- Advantis Medical Imaging, Eindhoven, The Netherlands
| | - Rachel Goldstein
- EEG and Epilepsy Unit, Department of Neurology, University Hospitals of Geneva, 4 rue Gabrielle-Perret-Gentil, 1211, Genève 14, Switzerland
| | - Yann Seimbille
- Nuclear Medicine and Molecular Imaging Division, Department of Medical Imaging, University Hospitals of Geneva, 4 rue Gabrielle-Perret-Gentil, 1211, Genève 14, Switzerland
| | - Margitta Seeck
- Faculty of Medicine, Geneva University, 1211, Geneva, Switzerland.,EEG and Epilepsy Unit, Department of Neurology, University Hospitals of Geneva, 4 rue Gabrielle-Perret-Gentil, 1211, Genève 14, Switzerland
| | - Osman Ratib
- Nuclear Medicine and Molecular Imaging Division, Department of Medical Imaging, University Hospitals of Geneva, 4 rue Gabrielle-Perret-Gentil, 1211, Genève 14, Switzerland
| | - Sven Haller
- Faculty of Medicine, Geneva University, 1211, Geneva, Switzerland.,CIRD - Centre d'Imagerie Rive Droite, Rue Chantepoulet 21, 1201, Genève, Switzerland.,Department of Surgical Sciences, Radiology, Uppsala University, Uppsala, Sweden
| | - Fabienne Picard
- Faculty of Medicine, Geneva University, 1211, Geneva, Switzerland. .,EEG and Epilepsy Unit, Department of Neurology, University Hospitals of Geneva, 4 rue Gabrielle-Perret-Gentil, 1211, Genève 14, Switzerland.
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28
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Tsvetaeva DA, Sitnikova EY, Raevsky VV. The Responses of Neurons of the Somatosensory Cortex to Stimulation of the Posterior Thalamus (PO) in WAG/Rij Rats Genetically Predisposed to Absence Epilepsy. DOKLADY BIOLOGICAL SCIENCES : PROCEEDINGS OF THE ACADEMY OF SCIENCES OF THE USSR, BIOLOGICAL SCIENCES SECTIONS 2018; 480:75-77. [PMID: 30009343 DOI: 10.1134/s0012496618030109] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Indexed: 11/23/2022]
Abstract
In genetically predisposed WAG/Rij rats and healthy Wistar rats, we studied functioning of the paralemniscal region of the thalamo-cortical system. The responses of neurons of the somatosensory cortex to single electrical stimulation of the posterior nucleus of the thalamus were recorded in two- to three-monthold rats within the period when the epileptic activity was not developed. We revealed lower number of shortterm inhibitory responses in WAG/Rij rats as compared to Wistar rats. This may create preconditions for the spreading of spike-wave activity in the somatosensory cortex, which is an electrophysiological sign of absence epilepsy.
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Affiliation(s)
- D A Tsvetaeva
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia.,Pirogov Russian National Research Medical University, Ministry of Healthcare of the Russian Federation, Moscow, Russia
| | - E Yu Sitnikova
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia
| | - V V Raevsky
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia.
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29
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Klein PM, Lu AC, Harper ME, McKown HM, Morgan JD, Beenhakker MP. Tenuous Inhibitory GABAergic Signaling in the Reticular Thalamus. J Neurosci 2018; 38:1232-1248. [PMID: 29273603 PMCID: PMC5792478 DOI: 10.1523/jneurosci.1345-17.2017] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 09/20/2017] [Accepted: 11/03/2017] [Indexed: 11/21/2022] Open
Abstract
Maintenance of a low intracellular Cl- concentration ([Cl-]i) is critical for enabling inhibitory neuronal responses to GABAA receptor-mediated signaling. Cl- transporters, including KCC2, and extracellular impermeant anions ([A]o) of the extracellular matrix are both proposed to be important regulators of [Cl-]i Neurons of the reticular thalamic (RT) nucleus express reduced levels of KCC2, indicating that GABAergic signaling may produce excitation in RT neurons. However, by performing perforated patch recordings and calcium imaging experiments in rats (male and female), we find that [Cl-]i remains relatively low in RT neurons. Although we identify a small contribution of [A]o to a low [Cl-]i in RT neurons, our results also demonstrate that reduced levels of KCC2 remain sufficient to maintain low levels of Cl- Reduced KCC2 levels, however, restrict the capacity of RT neurons to rapidly extrude Cl- following periods of elevated GABAergic signaling. In a computational model of a local RT network featuring slow Cl- extrusion kinetics, similar to those we found experimentally, model RT neurons are predisposed to an activity-dependent switch from GABA-mediated inhibition to excitation. By decreasing the activity threshold required to produce excitatory GABAergic signaling, weaker stimuli are able to propagate activity within the model RT nucleus. Our results indicate the importance of even diminished levels of KCC2 in maintaining inhibitory signaling within the RT nucleus and suggest how this important activity choke point may be easily overcome in disorders such as epilepsy.SIGNIFICANCE STATEMENT Precise regulation of intracellular Cl- levels ([Cl-]i) preserves appropriate, often inhibitory, GABAergic signaling within the brain. However, there is disagreement over the relative contribution of various mechanisms that maintain low [Cl-]i We found that the Cl- transporter KCC2 is an important Cl- extruder in the reticular thalamic (RT) nucleus, despite this nucleus having remarkably low KCC2 immunoreactivity relative to other regions of the adult brain. We also identified a smaller contribution of fixed, impermeant anions ([A]o) to lowering [Cl-]i in RT neurons. Inhibitory signaling among RT neurons is important for preventing excessive activation of RT neurons, which can be responsible for generating seizures. Our work suggests that KCC2 critically restricts the spread of activity within the RT nucleus.
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Affiliation(s)
- Peter M Klein
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia 22903
| | - Adam C Lu
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia 22903
| | - Megan E Harper
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia 22903
| | - Hannah M McKown
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia 22903
| | - Jessica D Morgan
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia 22903
| | - Mark P Beenhakker
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia 22903
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30
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Maksimenko VA, Lüttjohann A, Makarov VV, Goremyko MV, Koronovskii AA, Nedaivozov V, Runnova AE, van Luijtelaar G, Hramov AE, Boccaletti S. Macroscopic and microscopic spectral properties of brain networks during local and global synchronization. Phys Rev E 2017; 96:012316. [PMID: 29347072 DOI: 10.1103/physreve.96.012316] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2017] [Indexed: 11/07/2022]
Abstract
We introduce a practical and computationally not demanding technique for inferring interactions at various microscopic levels between the units of a network from the measurements and the processing of macroscopic signals. Starting from a network model of Kuramoto phase oscillators, which evolve adaptively according to homophilic and homeostatic adaptive principles, we give evidence that the increase of synchronization within groups of nodes (and the corresponding formation of synchronous clusters) causes also the defragmentation of the wavelet energy spectrum of the macroscopic signal. Our methodology is then applied to getting a glance into the microscopic interactions occurring in a neurophysiological system, namely, in the thalamocortical neural network of an epileptic brain of a rat, where the group electrical activity is registered by means of multichannel EEG. We demonstrate that it is possible to infer the degree of interaction between the interconnected regions of the brain during different types of brain activities and to estimate the regions' participation in the generation of the different levels of consciousness.
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Affiliation(s)
- Vladimir A Maksimenko
- Yuri Gagarin State Technical University of Saratov, REC "Nonlinear Dynamics of Complex Systems," Saratov 410054, Russia
| | - Annika Lüttjohann
- University of Münster, Institute of Physiology I, Münster 48149, Germany
| | - Vladimir V Makarov
- Yuri Gagarin State Technical University of Saratov, REC "Nonlinear Dynamics of Complex Systems," Saratov 410054, Russia
| | - Mikhail V Goremyko
- Yuri Gagarin State Technical University of Saratov, REC "Nonlinear Dynamics of Complex Systems," Saratov 410054, Russia
| | - Alexey A Koronovskii
- Saratov State University, Faculty of Nonlinear Processes, Saratov 410012, Russia
| | - Vladimir Nedaivozov
- Yuri Gagarin State Technical University of Saratov, REC "Nonlinear Dynamics of Complex Systems," Saratov 410054, Russia
| | - Anastasia E Runnova
- Yuri Gagarin State Technical University of Saratov, REC "Nonlinear Dynamics of Complex Systems," Saratov 410054, Russia
| | | | - Alexander E Hramov
- Yuri Gagarin State Technical University of Saratov, REC "Nonlinear Dynamics of Complex Systems," Saratov 410054, Russia
| | - Stefano Boccaletti
- CNR-Institute for complex systems, Sesto Fiorentino 50019, Italy.,The Italian Embassy in Tel Aviv, Tel Aviv 68125, Israel
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31
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Abstract
The ultimate goal of epileptology is the complete abolishment of epileptic seizures. This might be achieved by a system that predicts seizure onset combined with a system that interferes with the process that leads to the onset of a seizure. Seizure prediction remains, as of yet, unresolved in absence-epilepsy, due to the sudden onset of seizures. We have developed a real-time absence seizure prediction algorithm, evaluated it and implemented it in an on-line, closed-loop brain stimulation system designed to prevent the spike-wave-discharges (SWDs), typical for absence epilepsy, in a genetic rat model. The algorithm corretly predicted 88% of the SWDs while the remaining were quickly detected. A high number of false-positive detections occurred mainly during light slow-wave-sleep. Inclusion of criteria to prevent false-positives greatly reduced the false alarm rate but decreased the sensitivity of the algoritm. Implementation of the latter version into a closed-loop brain-stimulation-system resulted in a 72% decrease in seizure activity. In contrast to long standing beliefs that SWDs are unpredictable, these results demonstrate that they can be predicted and that the development of closed-loop seizure prediction and prevention systems is a feasable step towards interventions to attain control and freedom from epileptic seizures.
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32
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Barad Z, Grattan DR, Leitch B. NMDA Receptor Expression in the Thalamus of the Stargazer Model of Absence Epilepsy. Sci Rep 2017; 7:42926. [PMID: 28220891 PMCID: PMC5318904 DOI: 10.1038/srep42926] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 01/16/2017] [Indexed: 11/09/2022] Open
Abstract
In the stargazer mouse model of absence epilepsy, altered corticothalamic excitation of reticular thalamic nucleus (RTN) neurons has been suggested to contribute to abnormal synchronicity in the corticothalamic-thalamocortical circuit, leading to spike-wave discharges, the hallmark of absence seizures. AMPA receptor expression and function are decreased in stargazer RTN, due to a mutation of AMPAR auxiliary subunit stargazin. It is unresolved and debated, however, if decreased excitation of RTN is compatible with epileptogenesis. We tested the hypothesis that relative NMDAR expression may be increased in RTN and/or thalamic synapses in stargazers using Western blot on dissected thalamic nuclei and biochemically isolated synapses, as well as immunogold cytochemistry in RTN. Expression of main NMDAR subunits was variable in stargazer RTN and relay thalamus; however, mean expression values were not statistically significantly different compared to controls. Furthermore, no systematic changes in synaptic NMDAR levels could be detected in stargazer thalamus. In contrast, AMPAR subunits were markedly decreased in both nucleus-specific and synaptic preparations. Thus, defective AMPAR trafficking in stargazer thalamus does not appear to lead to a ubiquitous compensatory increase in total and synaptic NMDAR expression, suggesting that elevated NMDAR function is not mediated by changes in protein expression in stargazer mice.
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Affiliation(s)
- Z Barad
- Department of Anatomy, Otago School of Biomedical Sciences, University of Otago, Dunedin, New Zealand.,Brain Health Research Centre, University of Otago, Dunedin, New Zealand
| | - D R Grattan
- Department of Anatomy, Otago School of Biomedical Sciences, University of Otago, Dunedin, New Zealand.,Centre for Neuroendocrinology, Dunedin, New Zealand
| | - B Leitch
- Department of Anatomy, Otago School of Biomedical Sciences, University of Otago, Dunedin, New Zealand.,Brain Health Research Centre, University of Otago, Dunedin, New Zealand
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33
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Just N, Sonnay S. Investigating the Role of Glutamate and GABA in the Modulation of Transthalamic Activity: A Combined fMRI-fMRS Study. Front Physiol 2017; 8:30. [PMID: 28197105 PMCID: PMC5281558 DOI: 10.3389/fphys.2017.00030] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 01/11/2017] [Indexed: 11/29/2022] Open
Abstract
The Excitatory-Inhibitory balance (EIB) between glutamatergic and GABAergic neurons is known to regulate the function of thalamocortical neurocircuits. The thalamus is known as an important relay for glutamatergic and GABAergic signals ascending/descending to/from the somatosensory cortex in rodents. However, new investigations attribute a larger role to thalamic nuclei as modulators of information processing within the cortex. In this study, functional Magnetic Resonance Spectroscopy (fMRS) was used to measure glutamate (Glu) and GABA associations with BOLD responses during activation of the thalamus to barrel cortex (S1BF) pathway at 9.4T. In line with previous studies in humans, resting GABA and Glu correlated negatively and positively respectively with BOLD responses in S1BF. Moreover, a significant negative correlation (R = −0.68, p = 0.0024) between BOLD responses in the thalamus and the barrel cortex was found. Rats with low Glu levels and high resting GABA levels in S1BF demonstrated lower BOLD responses in S1BF and high amplitude BOLD responses in the thalamus themselves linked to the release of high GABA levels during stimulation. In addition, early analysis of resting state functional connectivity suggested EIB controlled thalamocortical neuronal synchrony. We propose that the presented approach may be useful for further characterization of diseases affecting thalamocortical neurotransmission.
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Affiliation(s)
- Nathalie Just
- CIBM-AIT core, Ecole Polytechnique Fédérale de LausanneLausanne, Switzerland; University Hospital MünsterMünster, Germany
| | - Sarah Sonnay
- LIFMET, Ecole Polytechnique Fédérale de Lausanne Lausanne, Switzerland
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Williams MS, Altwegg-Boussac T, Chavez M, Lecas S, Mahon S, Charpier S. Integrative properties and transfer function of cortical neurons initiating absence seizures in a rat genetic model. J Physiol 2016; 594:6733-6751. [PMID: 27311433 DOI: 10.1113/jp272162] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Accepted: 05/23/2016] [Indexed: 12/11/2022] Open
Abstract
KEY POINTS Absence seizures are accompanied by spike-and-wave discharges in cortical electroencephalograms. These complex paroxysmal activities, affecting the thalamocortical networks, profoundly alter cognitive performances and preclude conscious perception. Here, using a well-recognized genetic model of absence epilepsy, we investigated in vivo how information processing was impaired in the ictogenic neurons, i.e. the population of cortical neurons responsible for seizure initiation. In between seizures, ictogenic neurons were more prone to generate bursting activity and their firing response to weak depolarizing events was considerably facilitated compared to control neurons. In the course of seizures, information processing became unstable in ictogenic cells, alternating between an increased and a decreased responsiveness to excitatory inputs, depending on the spike and wave patterns. The state-dependent modulation in the excitability of ictogenic neurons affects their inter-seizure transfer function and their time-to-time responsiveness to incoming inputs during absences. ABSTRACT Epileptic seizures result from aberrant cellular and/or synaptic properties that can alter the capacity of neurons to integrate and relay information. During absence seizures, spike-and-wave discharges (SWDs) interfere with incoming sensory inputs and preclude conscious experience. The Genetic Absence Epilepsy Rats from Strasbourg (GAERS), a well-established animal model of absence epilepsy, allows exploration of the cellular basis of this impaired information processing. Here, by combining in vivo electrocorticographic and intracellular recordings from GAERS and control animals, we investigated how the pro-ictogenic properties of seizure-initiating cortical neurons modify their integrative properties and input-output operation during inter-ictal periods and during the spike (S-) and wave (W-) cortical patterns alternating during seizures. In addition to a sustained depolarization and an excessive firing rate in between seizures, ictogenic neurons exhibited a pronounced hyperpolarization-activated depolarization compared to homotypic control neurons. Firing frequency versus injected current relations indicated an increased sensitivity of GAERS cells to weak excitatory inputs, without modifications in the trial-to-trial variability of current-induced firing. During SWDs, the W-component resulted in paradoxical effects in ictogenic neurons, associating an increased membrane input resistance with a reduction in the current-evoked firing responses. Conversely, the collapse of cell membrane resistance during the S-component was accompanied by an elevated current-evoked firing relative to W-sequences, which remained, however, lower compared to inter-ictal periods. These findings show a dynamic modulation of ictogenic neurons' intrinsic properties that may alter inter-seizure cortical function and participate in compromising information processing in cortical networks during absences.
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Affiliation(s)
- Mark S Williams
- Sorbonne Universités, UPMC Univ Paris 06, UPMC; INSERM U 1127, CNRS, UMR 7225, Hôpital Pitié-Salpêtrière, Institut du Cerveau et de la Moelle épinière, ICM, F-75013, Paris, France
| | - Tristan Altwegg-Boussac
- Sorbonne Universités, UPMC Univ Paris 06, UPMC; INSERM U 1127, CNRS, UMR 7225, Hôpital Pitié-Salpêtrière, Institut du Cerveau et de la Moelle épinière, ICM, F-75013, Paris, France
| | - Mario Chavez
- Sorbonne Universités, UPMC Univ Paris 06, UPMC; INSERM U 1127, CNRS, UMR 7225, Hôpital Pitié-Salpêtrière, Institut du Cerveau et de la Moelle épinière, ICM, F-75013, Paris, France
| | - Sarah Lecas
- Sorbonne Universités, UPMC Univ Paris 06, UPMC; INSERM U 1127, CNRS, UMR 7225, Hôpital Pitié-Salpêtrière, Institut du Cerveau et de la Moelle épinière, ICM, F-75013, Paris, France.,UPMC Univ Paris 06, F-75005, Paris, France
| | - Séverine Mahon
- Sorbonne Universités, UPMC Univ Paris 06, UPMC; INSERM U 1127, CNRS, UMR 7225, Hôpital Pitié-Salpêtrière, Institut du Cerveau et de la Moelle épinière, ICM, F-75013, Paris, France
| | - Stéphane Charpier
- Sorbonne Universités, UPMC Univ Paris 06, UPMC; INSERM U 1127, CNRS, UMR 7225, Hôpital Pitié-Salpêtrière, Institut du Cerveau et de la Moelle épinière, ICM, F-75013, Paris, France.,UPMC Univ Paris 06, F-75005, Paris, France
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Kohmann D, Lüttjohann A, Seidenbecher T, Coulon P, Pape HC. Short-term depression of gap junctional coupling in reticular thalamic neurons of absence epileptic rats. J Physiol 2016; 594:5695-710. [PMID: 26940972 DOI: 10.1113/jp271811] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 03/02/2016] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Gap junctional electrical coupling between neurons of the reticular thalamic nucleus (RTN) is critical for hypersynchrony in the thalamo-cortical network. This study investigates the role of electrical coupling in pathological rhythmogenesis in RTN neurons in a rat model of absence epilepsy. Rhythmic activation resulted in a Ca(2+) -dependent short-term depression (STD) of electrical coupling between pairs of RTN neurons in epileptic rats, but not in RTN of a non-epileptic control strain. Pharmacological blockade of gap junctions in RTN in vivo induced a depression of seizure activity. The STD of electrical coupling represents a mechanism of Ca(2+) homeostasis in RTN aimed to counteract excessive synchronization. ABSTRACT Neurons in the reticular thalamic nucleus (RTN) are coupled by electrical synapses, which play a major role in regulating synchronous activity. This study investigates electrical coupling in RTN neurons from a rat model of childhood absence epilepsy, genetic absence epilepsy rats from Strasbourg (GAERS), compared with a non-epileptic control (NEC) strain, to assess the impact on pathophysiological rhythmogenesis. Whole-cell recordings were obtained from pairs of RTN neurons of GAERS and NEC in vitro. Coupling was determined by injection of hyperpolarizing current steps in one cell and monitoring evoked voltage responses in both activated and coupled cell. The coupling coefficient (cc) was compared under resting condition, during pharmacological interventions and repeated activation using a series of current injections. The effect of gap junctional coupling on seizure expression was investigated by application of gap junctional blockers into RTN of GAERS in vivo. At resting conditions, cc did not differ between GAERS and NEC. During repeated activation, cc declined in GAERS but not in NEC. This depression in cc was restored within 25 s and was prevented by intracellular presence of BAPTA in the activated but not in the coupled cell. Local application of gap junctional blockers into RTN of GAERS in vivo resulted in a decrease of spike wave discharge (SWD) activity. Repeated activation results in a short-term depression (STD) of gap junctional coupling in RTN neurons of GAERS, depending on intracellular Ca(2+) mechanisms in the activated cell. As blockage of gap junctions in vivo results in a decrease of SWD activity, the STD observed in GAERS is considered a compensatory mechanism, aimed to dampen SWD activity.
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Affiliation(s)
| | | | - Thomas Seidenbecher
- Institute of Physiology I, Westfälische Wilhelms-University Münster, Münster, Germany
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Identification of Focal Epileptogenic Networks in Generalized Epilepsy Using Brain Functional Connectivity Analysis of Bilateral Intracranial EEG Signals. Brain Topogr 2016; 29:728-37. [DOI: 10.1007/s10548-016-0493-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 04/19/2016] [Indexed: 10/21/2022]
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37
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Karimzadeh F, Modarres Mousavi SM, Ghadiri T, Jafarian M, Soleimani M, Sadeghi SM, Mesgari M, Joghataei MT, Gorji A. The Modulatory Effect of Metabotropic Glutamate Receptor Type-1α on Spike-Wave Discharges in WAG/Rij Rats. Mol Neurobiol 2016; 54:846-854. [PMID: 26780454 DOI: 10.1007/s12035-016-9692-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Accepted: 01/05/2016] [Indexed: 02/06/2023]
Abstract
Modulatory function of metabotropic glutamate type 1 (mGlu1) receptors plays a crucial role in the pathophysiology of some neurological disorders, including schizophrenia and epilepsy. In this study, the expression of mGlu1α receptors in the thalamic nuclei was assessed during development of absence seizures in the WAG/Rij rats, a valid genetic animal model of absence epilepsy. In addition, the effect of pharmacological modulation of mGlu1α receptors in the laterodorsal (LD) nucleus of the thalamus on the characteristic features of bioelectrical brain activities in the WAG/Rij rats was assessed. The expression of mGlu1α receptors in the LD was assessed in four experimental groups of both WAG/Rij and Wistar rats with 2 and 6 months of age. Agonist and antagonist of mGlu1α receptors were infused in LD in the six months old WAG/Rij (epileptic) rats. The protein level of mGlu1α receptors in the thalamus of the 6-month-old WAG/Rij rats was lower than non-epileptic animals. In addition, the distribution of mGlu1α receptors in different thalamic nuclei was lower in the 6-month-old WAG/Rij compared to age-matched Wistar rats. The gene expression of mGlu1α receptor was also significantly lower in 6-month-old WAG/Rij rats in the LD compared to other animal groups. The microinjection of mGlu1α receptors agonist and antagonist in the LD reduced the duration of spike-wave discharges (SWDs) and increased the amplitude and duration of SWDs, respectively, in 6-month-old WAG/Rij rats. The alterations of mGlu1α receptors expression in the thalamus of epileptic WAG/Rij rats as well as its modulatory effects in the generation of SWDs suggest the potential of mGlu1 receptors as a therapeutic target in absence epilepsy.
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Affiliation(s)
- Fariba Karimzadeh
- Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran, Iran.,Shefa Neuroscience Research Center, Khatam Alanbia Hospital, Tehran, Iran
| | | | - Tahereh Ghadiri
- Shefa Neuroscience Research Center, Khatam Alanbia Hospital, Tehran, Iran
| | - Maryam Jafarian
- Shefa Neuroscience Research Center, Khatam Alanbia Hospital, Tehran, Iran
| | - Mansoureh Soleimani
- Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Shahin Mohammad Sadeghi
- Department of Plastic and Reconstructive Surgery, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Masoud Mesgari
- Klinik und Poliklinik für Neurochirurgie, Westfälische Wilhelms-Universität Münster, Münster, Germany.,Klinik und Poliklinik für Neurologie, Westfälische Wilhelms-Universität Münster, Münster, Germany.,Epilepsy Research Center, Westfälische Wilhelms-Universität Münster, Münster, Germany
| | | | - Ali Gorji
- Shefa Neuroscience Research Center, Khatam Alanbia Hospital, Tehran, Iran. .,Klinik und Poliklinik für Neurochirurgie, Westfälische Wilhelms-Universität Münster, Münster, Germany. .,Klinik und Poliklinik für Neurologie, Westfälische Wilhelms-Universität Münster, Münster, Germany. .,Epilepsy Research Center, Westfälische Wilhelms-Universität Münster, Münster, Germany.
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Wemhöner K, Kanyshkova T, Silbernagel N, Fernandez-Orth J, Bittner S, Kiper AK, Rinné S, Netter MF, Meuth SG, Budde T, Decher N. An N-terminal deletion variant of HCN1 in the epileptic WAG/Rij strain modulates HCN current densities. Front Mol Neurosci 2015; 8:63. [PMID: 26578877 PMCID: PMC4630678 DOI: 10.3389/fnmol.2015.00063] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Accepted: 10/13/2015] [Indexed: 11/26/2022] Open
Abstract
Rats of the Wistar Albino Glaxo/Rij (WAG/Rij) strain show symptoms resembling human absence epilepsy. Thalamocortical neurons of WAG/Rij rats are characterized by an increased HCN1 expression, a negative shift in Ih activation curve, and an altered responsiveness of Ih to cAMP. We cloned HCN1 channels from rat thalamic cDNA libraries of the WAG/Rij strain and found an N-terminal deletion of 37 amino acids. In addition, WAG-HCN1 has a stretch of six amino acids, directly following the deletion, where the wild-type sequence (GNSVCF) is changed to a polyserine motif. These alterations were found solely in thalamus mRNA but not in genomic DNA. The truncated WAG-HCN1 was detected late postnatal in WAG/Rij rats and was not passed on to rats obtained from pairing WAG/Rij and non-epileptic August Copenhagen Irish rats. Heterologous expression in Xenopus oocytes revealed 2.2-fold increased current amplitude of WAG-HCN1 compared to rat HCN1. While WAG-HCN1 channels did not have altered current kinetics or changed regulation by protein kinases, fluorescence imaging revealed a faster and more pronounced surface expression of WAG-HCN1. Using co-expression experiments, we found that WAG-HCN1 channels suppress heteromeric HCN2 and HCN4 currents. Moreover, heteromeric channels of WAG-HCN1 with HCN2 have a reduced cAMP sensitivity. Functional studies revealed that the gain-of-function of WAG-HCN1 is not caused by the N-terminal deletion alone, thus requiring a change of the N-terminal GNSVCF motif. Our findings may help to explain previous observations in neurons of the WAG/Rij strain and indicate that WAG-HCN1 may contribute to the genesis of absence seizures in WAG/Rij rats.
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Affiliation(s)
- Konstantin Wemhöner
- Institute for Physiology and Pathophysiology, Vegetative Physiology, Philipps-University of Marburg Marburg, Germany
| | - Tatyana Kanyshkova
- Institute for Physiology I, Westfälische Wilhelms-Universität Münster, Germany
| | - Nicole Silbernagel
- Institute for Physiology and Pathophysiology, Vegetative Physiology, Philipps-University of Marburg Marburg, Germany
| | | | - Stefan Bittner
- Department of Neurology, University Medical Center, Johannes Gutenberg-University Mainz Mainz, Germany
| | - Aytug K Kiper
- Institute for Physiology and Pathophysiology, Vegetative Physiology, Philipps-University of Marburg Marburg, Germany
| | - Susanne Rinné
- Institute for Physiology and Pathophysiology, Vegetative Physiology, Philipps-University of Marburg Marburg, Germany
| | - Michael F Netter
- Institute for Physiology and Pathophysiology, Vegetative Physiology, Philipps-University of Marburg Marburg, Germany
| | - Sven G Meuth
- Department of Neurology, Westfälische Wilhelms-Universität Münster, Germany
| | - Thomas Budde
- Institute for Physiology I, Westfälische Wilhelms-Universität Münster, Germany
| | - Niels Decher
- Institute for Physiology and Pathophysiology, Vegetative Physiology, Philipps-University of Marburg Marburg, Germany
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Wang G, Bochorishvili G, Chen Y, Salvati KA, Zhang P, Dubel SJ, Perez-Reyes E, Snutch TP, Stornetta RL, Deisseroth K, Erisir A, Todorovic SM, Luo JH, Kapur J, Beenhakker MP, Zhu JJ. CaV3.2 calcium channels control NMDA receptor-mediated transmission: a new mechanism for absence epilepsy. Genes Dev 2015. [PMID: 26220996 PMCID: PMC4526737 DOI: 10.1101/gad.260869.115] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
CaV3.2 T-type calcium channels, encoded by CACNA1H, are expressed throughout the brain, yet their general function remains unclear. We discovered that CaV3.2 channels control NMDA-sensitive glutamatergic receptor (NMDA-R)-mediated transmission and subsequent NMDA-R-dependent plasticity of AMPA-R-mediated transmission at rat central synapses. Interestingly, functional CaV3.2 channels primarily incorporate into synapses, replace existing CaV3.2 channels, and can induce local calcium influx to control NMDA transmission strength in an activity-dependent manner. Moreover, human childhood absence epilepsy (CAE)-linked hCaV3.2(C456S) mutant channels have a higher channel open probability, induce more calcium influx, and enhance glutamatergic transmission. Remarkably, cortical expression of hCaV3.2(C456S) channels in rats induces 2- to 4-Hz spike and wave discharges and absence-like epilepsy characteristic of CAE patients, which can be suppressed by AMPA-R and NMDA-R antagonists but not T-type calcium channel antagonists. These results reveal an unexpected role of CaV3.2 channels in regulating NMDA-R-mediated transmission and a novel epileptogenic mechanism for human CAE.
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Affiliation(s)
- Guangfu Wang
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Genrieta Bochorishvili
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Yucai Chen
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Kathryn A Salvati
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Peng Zhang
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Steve J Dubel
- Laboratoire de Génomique Fonctionnelle, Département de Physiologie, Unité Propre de Recherche 2580, Centre National de la Recherche Scientifique, 34396 Montpellier, France
| | - Edward Perez-Reyes
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Terrance P Snutch
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada; Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Ruth L Stornetta
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Karl Deisseroth
- Department of Bioengineering, Stanford University, Stanford, California 94305, USA; Howard Hughes Medical Institute, Stanford University, Stanford, California 94305, USA
| | - Alev Erisir
- Department of Psychology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Slobodan M Todorovic
- Department of Anesthesiology, University of Virginia, Charlottesville, Virginia 22908, USA; Department of Neuroscience, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Jian-Hong Luo
- Department of Neurobiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Jaideep Kapur
- Department of Neurology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Mark P Beenhakker
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - J Julius Zhu
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA; Department of Neuroscience, University of Virginia, Charlottesville, Virginia 22908, USA
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Rodgers KM, Dudek FE, Barth DS. Progressive, Seizure-Like, Spike-Wave Discharges Are Common in Both Injured and Uninjured Sprague-Dawley Rats: Implications for the Fluid Percussion Injury Model of Post-Traumatic Epilepsy. J Neurosci 2015; 35:9194-204. [PMID: 26085641 PMCID: PMC6605152 DOI: 10.1523/jneurosci.0919-15.2015] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 04/19/2015] [Accepted: 05/10/2015] [Indexed: 01/05/2023] Open
Abstract
Variable-duration oscillations and repetitive, high-voltage spikes have been recorded in the electrocorticogram (ECoG) of rats weeks and months after fluid percussion injury (FPI), a model of traumatic brain injury. These ECoG events, which have many similarities to spike-wave-discharges (SWDs) and absence seizures, have been proposed to represent nonconvulsive seizures characteristic of post-traumatic epilepsy (PTE). The present study quantified features of SWD episodes in rats at different time points after moderate to severe FPI, and compared them with age-matched control rats. Control and FPI-injured rats at 1 year of age displayed large-amplitude and frequent SWD events at frontal and parietal recording sites. At 3-6 months, SWDs were shorter in duration and less frequent; extremely brief SWDs (i.e., "larval") were detected as early as 1 month. The onset of the SWDs was nearly always synchronous across electrodes and of larger amplitude in frontal regions. A sensory stimulus, such as a click, immediately and consistently stopped the occurrence of the SWDs. SWDs were consistently accompanied by behavioral arrest. All features of SWDs in control and experimental (FPI) rats were indistinguishable. None of the FPI-treated rats developed nonconvulsive or convulsive seizures that could be distinguished electrographically or behaviorally from SWDs. Because SWDs have features similar to genetic absence seizures, these results challenge the hypothesis that SWDs after FPI reflect PTE.
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Affiliation(s)
- Krista M Rodgers
- Department of Psychology and Neuroscience, University of Colorado, Boulder, Colorado 80309, and
| | - F Edward Dudek
- Department of Neurosurgery, University of Utah School of Medicine, Salt Lake City, Utah 84108
| | - Daniel S Barth
- Department of Psychology and Neuroscience, University of Colorado, Boulder, Colorado 80309, and
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