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Groulx-Boivin E, Bouchet T, Myers KA. Understanding of Consciousness in Absence Seizures: A Literature Review. Neuropsychiatr Dis Treat 2024; 20:1345-1353. [PMID: 38947367 PMCID: PMC11212660 DOI: 10.2147/ndt.s391052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2024] [Accepted: 06/14/2024] [Indexed: 07/02/2024] Open
Abstract
Absence seizures are classically associated with behavioral arrest and transient deficits in consciousness, yet substantial variability exists in the severity of the impairment. Despite several decades of research on the topic, the pathophysiology of absence seizures and the mechanisms underlying behavioral impairment remain unclear. Several rationales have been proposed including widespread cortical deactivation, reduced perception of external stimuli, and transient suspension of the default mode network, among others. This review aims to summarize the current knowledge on the neural correlates of impaired consciousness in absence seizures. We review evidence from studies using animal models of absence epilepsy, electroencephalography, functional magnetic resonance imaging, magnetoencephalography, positron emission tomography, and single photon emission computed tomography.
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Affiliation(s)
- Emilie Groulx-Boivin
- Department of Neurology and Neurosurgery, Montreal Children’s Hospital, McGill University, Montreal, Quebec, Canada
- Department of Pediatrics, Montreal Children’s Hospital, McGill University, Montreal, Quebec, Canada
| | - Tasha Bouchet
- Department of Medicine, McGill University, Montreal, Quebec, Canada
| | - Kenneth A Myers
- Department of Neurology and Neurosurgery, Montreal Children’s Hospital, McGill University, Montreal, Quebec, Canada
- Department of Pediatrics, Montreal Children’s Hospital, McGill University, Montreal, Quebec, Canada
- Faculty of Medicine and Health Sciences, McGill University, Montreal, Quebec, Canada
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2
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Wachsmuth L, Hebbelmann L, Prade J, Kohnert LC, Lambers H, Lüttjohann A, Budde T, Hess A, Faber C. Epilepsy-related functional brain network alterations are already present at an early age in the GAERS rat model of genetic absence epilepsy. Front Neurol 2024; 15:1355862. [PMID: 38529038 PMCID: PMC10961455 DOI: 10.3389/fneur.2024.1355862] [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: 12/14/2023] [Accepted: 02/16/2024] [Indexed: 03/27/2024] Open
Abstract
Introduction Genetic Absence Epilepsy Rats from Strasbourg (GAERS) represent a model of genetic generalized epilepsy. The present longitudinal study in GAERS and age-matched non-epileptic controls (NEC) aimed to characterize the epileptic brain network using two functional measures, resting state-functional magnetic resonance imaging (rs-fMRI) and manganese-enhanced MRI (MEMRI) combined with morphometry, and to investigate potential brain network alterations, following long-term seizure activity. Methods Repeated rs-fMRI measurements at 9.4 T between 3 and 8 months of age were combined with MEMRI at the final time point of the study. We used graph theory analysis to infer community structure and global and local network parameters from rs-fMRI data and compared them to brain region-wise manganese accumulation patterns and deformation-based morphometry (DBM). Results Functional connectivity (FC) was generally higher in GAERS when compared to NEC. Global network parameters and community structure were similar in NEC and GAERS, suggesting efficiently functioning networks in both strains. No progressive FC changes were observed in epileptic animals. Network-based statistics (NBS) revealed stronger FC within the cortical community, including regions of association and sensorimotor cortex, and with basal ganglia and limbic regions in GAERS, irrespective of age. Higher manganese accumulation in GAERS than in NEC was observed at 8 months of age, consistent with higher overall rs-FC, particularly in sensorimotor cortex and association cortex regions. Functional measures showed less similarity in subcortical regions. Whole brain volumes of 8 months-old GAERS were higher when compared to age-matched NEC, and DBM revealed increased volumes of several association and sensorimotor cortex regions and of the thalamus. Discussion rs-fMRI, MEMRI, and volumetric data collectively suggest the significance of cortical networks in GAERS, which correlates with an increased fronto-central connectivity in childhood absence epilepsy (CAE). Our findings also verify involvement of basal ganglia and limbic regions. Epilepsy-related network alterations are already present in juvenile animals. Consequently, this early condition seems to play a greater role in dynamic brain function than chronic absence seizures.
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Affiliation(s)
- Lydia Wachsmuth
- Clinic of Radiology, University of Münster, Münster, Germany
| | - Leo Hebbelmann
- Clinic of Radiology, University of Münster, Münster, Germany
| | - Jutta Prade
- Department of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
| | - Laura C. Kohnert
- Department of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
| | | | | | - Thomas Budde
- Institute of Physiology I, University of Münster, Münster, Germany
| | - Andreas Hess
- Department of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
- Department of Neuroradiology, University Hospital Erlangen, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
- FAU NeW – Research Center for New Bioactive Compounds, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
| | - Cornelius Faber
- Clinic of Radiology, University of Münster, Münster, Germany
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ÇELİK ZB, TİRYAKİ ES, TÜRKDÖNMEZ E, ÇİÇEKLİ MN, ALTUN A, GÜNAYDIN C. Parallel changes in the promoter methylation of voltage-gated T-type calcium channel alpha 1 subunit G and histone deacetylase activity in the WAG/Rij model of absence epilepsy. JOURNAL OF HEALTH SCIENCES AND MEDICINE 2023. [DOI: 10.32322/jhsm.1207399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Objective: In the last two decades, research on epigenetic mechanisms has expanded dramatically. Recent studies demonstrated that epigenetic mechanisms regulate epilepsy and epileptogenic pathologies. In this study, we aimed to investigate changes in the promoter methylation status of the voltage-gated T-type calcium channel alpha 1 subunit G (CACNA1G) gene and total histone deacetylase activity in Wistar Albino Glaxo/Rijswijk (WAG/Rij) rats which is one of the commonly used genetic absence rat models of epilepsy in the three different age groups (3, 6, and 9 months old) on both sexes.
Material and Method: Evaluation of changes in the spike-wave discharges (SWDs) was performed with electrocorticography (ECoG). The promoter methylation status of the CACNA1G gene was determined by methylation-specific PCR (MSP), and histone deacetylase (HDAC) activity was determined spectrophotometrically.
Results: Our results demonstrated that the number of SWDs increased time-dependent in WAG/Rij. Additionally, it was observed that CACNA1G promoter methylation decreased, and total HDAC activity increased with age in both sexes.
Conclusion: Our results provide further support for epigenetic regulation in the absence epilepsy phenotype and suggest that the underlying mechanism behind the increase in the number of SWDs with age in the WAG/Rij animals might be regulated by CACNA1G promoter methylation or HDAC activity.
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Hermann BP, Struck AF, Busch RM, Reyes A, Kaestner E, McDonald CR. Neurobehavioural comorbidities of epilepsy: towards a network-based precision taxonomy. Nat Rev Neurol 2021; 17:731-746. [PMID: 34552218 PMCID: PMC8900353 DOI: 10.1038/s41582-021-00555-z] [Citation(s) in RCA: 58] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/10/2021] [Indexed: 02/06/2023]
Abstract
Cognitive and behavioural comorbidities are prevalent in childhood and adult epilepsies and impose a substantial human and economic burden. Over the past century, the classic approach to understanding the aetiology and course of these comorbidities has been through the prism of the medical taxonomy of epilepsy, including its causes, course, characteristics and syndromes. Although this 'lesion model' has long served as the organizing paradigm for the field, substantial challenges to this model have accumulated from diverse sources, including neuroimaging, neuropathology, neuropsychology and network science. Advances in patient stratification and phenotyping point towards a new taxonomy for the cognitive and behavioural comorbidities of epilepsy, which reflects the heterogeneity of their clinical presentation and raises the possibility of a precision medicine approach. As we discuss in this Review, these advances are informing the development of a revised aetiological paradigm that incorporates sophisticated neurobiological measures, genomics, comorbid disease, diversity and adversity, and resilience factors. We describe modifiable risk factors that could guide early identification, treatment and, ultimately, prevention of cognitive and broader neurobehavioural comorbidities in epilepsy and propose a road map to guide future research.
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Affiliation(s)
- Bruce P. Hermann
- Department of Neurology, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA.,
| | - Aaron F. Struck
- Department of Neurology, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA.,William S. Middleton Veterans Administration Hospital, Madison, WI, USA
| | - Robyn M. Busch
- Epilepsy Center and Department of Neurology, Neurological Institute, Cleveland Clinic, Cleveland, OH, USA.,Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Anny Reyes
- Department of Psychiatry and Center for Multimodal Imaging and Genetics, University of California, San Diego, San Diego, CA, USA
| | - Erik Kaestner
- Department of Psychiatry and Center for Multimodal Imaging and Genetics, University of California, San Diego, San Diego, CA, USA
| | - Carrie R. McDonald
- Department of Psychiatry and Center for Multimodal Imaging and Genetics, University of California, San Diego, San Diego, CA, USA
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Welch WP, Hect JL, Abel TJ. Case Report: Responsive Neurostimulation of the Centromedian Thalamic Nucleus for the Detection and Treatment of Seizures in Pediatric Primary Generalized Epilepsy. Front Neurol 2021; 12:656585. [PMID: 33995254 PMCID: PMC8113700 DOI: 10.3389/fneur.2021.656585] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 03/22/2021] [Indexed: 11/13/2022] Open
Abstract
Up to 20% of pediatric patients with primary generalized epilepsy (PGE) will not respond effectively to medication for seizure control. Responsive neurostimulation (RNS) is a promising therapy for pediatric patients with drug-resistant epilepsy and has been shown to be an effective therapy for reducing seizure frequency and severity in adult patients. RNS of the centromedian nucleus of the thalamus may help to prevent loss of awareness during seizure activity in PGE patients with absence seizures. Here we present a 16-year-old male, with drug-resistant PGE with absence seizures, characterized by 3 Hz spike-and-slow-wave discharges on EEG, who achieved a 75% reduction in seizure frequency following bilateral RNS of the centromedian nuclei. At 6-months post-implant, this patient reported complete resolution of the baseline daily absence seizure activity, and decrease from 3-4 generalized convulsive seizures per month to 1 per month. RNS recordings showed well-formed 3 Hz spike-wave discharges in bilateral CM nuclei, further supporting the notion that clinically relevant ictal discharges in PGE can be detected in CM. This report demonstrates that CM RNS can detect PGE-related seizures in the CM nucleus and deliver therapeutic stimulation.
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Affiliation(s)
- William P Welch
- Division of Pediatric Neurology, Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Jasmine L Hect
- Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Taylor J Abel
- Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States.,Department of Bioengineering, University of Pittsburgh Swanson School of Engineering, Pittsburgh, PA, United States
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Wachsmuth L, Datunashvili M, Kemper K, Albers F, Lambers H, Lüttjohann A, Kreitz S, Budde T, Faber C. Retrosplenial Cortex Contributes to Network Changes during Seizures in the GAERS Absence Epilepsy Rat Model. Cereb Cortex Commun 2021; 2:tgab023. [PMID: 34296168 PMCID: PMC8263073 DOI: 10.1093/texcom/tgab023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 03/15/2021] [Accepted: 03/16/2021] [Indexed: 11/14/2022] Open
Abstract
Resting state-fMRI was performed to explore brain networks in Genetic Absence Epilepsy Rats from Strasbourg and in nonepileptic controls (NEC) during monitoring of the brain state by simultaneous optical Ca2+-recordings. Graph theoretical analysis allowed for the identification of acute and chronic network changes and revealed preserved small world topology before and after seizure onset. The most prominent acute change in network organization during seizures was the segregation of cortical regions from the remaining brain. Stronger connections between thalamic with limbic regions compared with preseizure state indicated network regularization during seizures. When comparing between strains, intrathalamic connections were prominent in NEC, on local level represented by higher thalamic strengths and hub scores. Subtle differences were observed for retrosplenial cortex (RS), forming more connections beyond cortex in epileptic rats, and showing a tendency to lateralization during seizures. A potential role of RS as hub between subcortical and cortical regions in epilepsy was supported by increased numbers of parvalbumin-positive (PV+) interneurons together with enhanced inhibitory synaptic activity and neuronal excitability in pyramidal neurons. By combining multimodal fMRI data, graph theoretical methods, and electrophysiological recordings, we identified the RS as promising target for modulation of seizure activity and/or comorbidities.
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Affiliation(s)
- Lydia Wachsmuth
- Translational Research Imaging Center, Clinic for Radiology, University Hospital Münster, 48149 Münster, Germany
| | - Maia Datunashvili
- Institute of Physiology I, University of Münster, 48149 Münster, Germany
| | - Katharina Kemper
- Translational Research Imaging Center, Clinic for Radiology, University Hospital Münster, 48149 Münster, Germany
| | - Franziska Albers
- Translational Research Imaging Center, Clinic for Radiology, University Hospital Münster, 48149 Münster, Germany
| | - Henriette Lambers
- Translational Research Imaging Center, Clinic for Radiology, University Hospital Münster, 48149 Münster, Germany
| | - Annika Lüttjohann
- Institute of Physiology I, University of Münster, 48149 Münster, Germany
| | - Silke Kreitz
- Experimental and Clinical Pharmacology and Toxicology, University of Erlangen, 91054 Erlangen, Germany
| | - Thomas Budde
- Institute of Physiology I, University of Münster, 48149 Münster, Germany
| | - Cornelius Faber
- Translational Research Imaging Center, Clinic for Radiology, University Hospital Münster, 48149 Münster, Germany
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Wang X, Chen B, Jin L, Zhang W, Liu Y. Eight years follow-up of a generalized epilepsy patient with eating-induced late-onset epileptic spasms and atypical absence with myoclonic jerks. Brain Dev 2021; 43:160-165. [PMID: 32792174 DOI: 10.1016/j.braindev.2020.07.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 07/22/2020] [Accepted: 07/27/2020] [Indexed: 11/28/2022]
Abstract
PURPOSE Eating epilepsy was previously known as a kind of focal reflex epilepsy. However, the development of eating-induced multiple generalized seizures and the associated EEG changes were rarely reported. Herein, we present a 13-year-old generalized epilepsy patient with eating-induced generalized seizures since the age of 5. CASE PRESENTATION The 13-year-old male patient had suffered from late-onset eating-induced epileptic spasms during the meal since the age of 5. Meanwhile, he also experienced spontaneous epileptic spasms during the period of sleep. The seizure frequency and type gradually increased from 7 years of age. In addition to epileptic spasms, he started experiencing atypical absence with myoclonic jerks during the meal. Ictal EEG presented as the appearance of an irregular slow-wave mixed with generalized polyspike wave with the intake of food, and gradually evolved to bursts of generalized polyspike wave complexes. At the end of the meal, the EEG returned to normal. Nevertheless, at the age of 13, his seizure frequency increased and appeared new seizure type, and besides epileptic spasm and atypical absence, he began to experience myoclonic seizure during sleep and awaking-generalized tonic-clonic seizure in the morning. In this period he started taking valproic acid, topiramate and clonazepam, and his seizure frequency was reduced. CONCLUSION In conclusion, this case demonstrated the variability of eating induced multiple generalized seizure types, and eight years follow-up also indicates that generalized epilepsy progressed with age. The EEG and clinical changes of our patient contribute to a better understanding of the electro-clinical features of eating-induced multiple generalized seizures and the course of generalized epilepsy with such seizures.
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Affiliation(s)
- Xiaoli Wang
- Epilepsy and Sleep Disorders Unit, Department of Neurology, Xijing Hospital, Air Force Military Medical University, Xi'an, China
| | - Beibei Chen
- Epilepsy and Sleep Disorders Unit, Department of Neurology, Xijing Hospital, Air Force Military Medical University, Xi'an, China
| | - Lang Jin
- Epilepsy and Sleep Disorders Unit, Department of Neurology, Xijing Hospital, Air Force Military Medical University, Xi'an, China
| | - Wenjuan Zhang
- Epilepsy and Sleep Disorders Unit, Department of Neurology, Xijing Hospital, Air Force Military Medical University, Xi'an, China
| | - Yonghong Liu
- Epilepsy and Sleep Disorders Unit, Department of Neurology, Xijing Hospital, Air Force Military Medical University, Xi'an, China.
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Owolabi LF, Reda AA, El Sayed R, Morsy DFM, Enwere OO, Mba UA, Adamu B, AlGhamdi M. Study of electroencephalography in people with generalized epilepsy in a Saudi population. J Community Hosp Intern Med Perspect 2020; 10:549-554. [PMID: 33194127 PMCID: PMC7599013 DOI: 10.1080/20009666.2020.1809255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
Affiliation(s)
| | | | | | | | | | | | - Bappa Adamu
- College of Medicine, University of Bisha, Bisha, Saudi Arabia
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9
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Barone V, van Putten MJAM, Visser GH. Absence epilepsy: Characteristics, pathophysiology, attention impairments, and the related risk of accidents. A narrative review. Epilepsy Behav 2020; 112:107342. [PMID: 32861896 DOI: 10.1016/j.yebeh.2020.107342] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 07/10/2020] [Accepted: 07/11/2020] [Indexed: 12/15/2022]
Abstract
OBJECTIVE Absence epilepsy (AE) is related to both cognitive and physical impairments. In this narrative review, we critically discuss the pathophysiology of AE and the impairment of attention in children and adolescents with AE. In particular, we contextualize the attentive dysfunctions of AE with the associated risks, such as accidental injuries. DATA SOURCE An extensive literature search on attention deficits and the rate of accidental injuries in AE was run. The search was conducted on Scopus, Pubmed, and the online libraries of the University of Twente and Maastricht University. Relevant references of the included articles were added. Retrospective and prospective studies, case reports, meta-analysis, and narrative reviews were included. Only studies written in English were considered. Date of last search is February 2020. The keywords used were "absence epilepsy" AND "attention"/"awareness", "absence epilepsy" AND "accidental injuries"/"accident*"/"injuries". RESULTS Ten retrospective and two prospective studies on cognition and AE were fully screened. Seventeen papers explicitly referring to attention in AE were reviewed. Just one paper was found to specifically focus on accidental injuries and AE, while twelve studies generally referring to epilepsy syndromes - among which AE - and related accidents were included. CONCLUSION Absence epilepsy and attention deficits show some patterns of pathophysiological association. This relation may account for dysfunctions in everyday activities in the pediatric population. Particular metrics, such as the risk related to biking in children with AE, should be used in future studies to address the problem in a novel way and to impact clinical indications.
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Affiliation(s)
- Valentina Barone
- Twente Medical System International B.V. (TMSi), Zutphenstraat 57, 7575EJ Oldenzaal, the Netherlands; Clinical Neurophysiology (CNPH), Technohal Univeristy of Twente, Hallenweg 5, 7522 NH, the Netherlands.
| | - Michel J A M van Putten
- Clinical Neurophysiology (CNPH), Technohal Univeristy of Twente, Hallenweg 5, 7522 NH, the Netherlands; Department of Clinical Neurophysiology, Medisch Spectrum Twente, Koningsplein 1, 7512 KZ Enschede, the Netherlands..
| | - Gerhard H Visser
- Stichting Epilepsie Instellingen Nederland (SEIN), Achterweg 2, 2103 SW Heemstede, the Netherlands.
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Kim DS, Anantharam P, Padhi P, Thedens DR, Li G, Gilbreath E, Rumbeiha WK. Transcriptomic profile analysis of brain inferior colliculus following acute hydrogen sulfide exposure. Toxicology 2020; 430:152345. [PMID: 31843631 PMCID: PMC8324331 DOI: 10.1016/j.tox.2019.152345] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 12/09/2019] [Accepted: 12/12/2019] [Indexed: 12/11/2022]
Abstract
Hydrogen sulfide (H2S) is a gaseous molecule found naturally in the environment, and as an industrial byproduct, and is known to cause acute death and induces long-term neurological disorders following acute high dose exposures. Currently, there is no drug approved for treatment of acute H2S-induced neurotoxicity and/or neurological sequelae. Lack of a deep understanding of pathogenesis of H2S-induced neurotoxicity has delayed the development of appropriate therapeutic drugs that target H2S-induced neuropathology. RNA sequencing analysis was performed to elucidate the cellular and molecular mechanisms of H2S-induced neurodegeneration, and to identify key molecular elements and pathways that contribute to H2S-induced neurotoxicity. C57BL/6J mice were exposed by whole body inhalation to 700 ppm of H2S for either one day, two consecutive days or 4 consecutive days. Magnetic resonance imaging (MRI) scan analyses showed H2S exposure induced lesions in the inferior colliculus (IC) and thalamus (TH). This mechanistic study focused on the IC. RNA Sequencing analysis revealed that mice exposed once, twice, or 4 times had 283, 193 and 296 differentially expressed genes (DEG), respectively (q-value < 0.05, fold-change> 1.5). Hydrogen sulfide exposure modulated multiple biological pathways including unfolded protein response, neurotransmitters, oxidative stress, hypoxia, calcium signaling, and inflammatory response in the IC. Hydrogen sulfide exposure activated PI3K/Akt and MAPK signaling pathways. Pro-inflammatory cytokines were shown to be potential initiators of the modulated signaling pathways following H2S exposure. Furthermore, microglia were shown to release IL-18 and astrocytes released both IL-1β and IL-18 in response to H2S. This transcriptomic analysis data revealed complex signaling pathways involved in H2S-induced neurotoxicity and may provide important associated mechanistic insights.
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Affiliation(s)
- Dong-Suk Kim
- VDPAM, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
| | - Poojya Anantharam
- VDPAM, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
| | - Piyush Padhi
- VDPAM, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
| | - Daniel R Thedens
- Radiology, School of Medicine, University of Iowa, Iowa City, IA, United States
| | - Ganwu Li
- VDPAM, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
| | - Ebony Gilbreath
- Department of Pathobiology, College of Veterinary Medicine, Tuskegee University, United States
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11
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Spike-and-Wave Discharges Are Not Pathological Sleep Spindles, Network-Level Aspects of Age-Dependent Absence Seizure Development in Rats. eNeuro 2020; 7:ENEURO.0253-19.2019. [PMID: 31862790 PMCID: PMC6944477 DOI: 10.1523/eneuro.0253-19.2019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Revised: 11/04/2019] [Accepted: 12/11/2019] [Indexed: 12/28/2022] Open
Abstract
Spike-and-wave discharges (SWDs) of absence epilepsy are considered as pathologic alterations of sleep spindles; however, their network-level relationship has never been convincingly revealed. In order to observe the development and generalization of the thalamocortical SWDs and the concomitant alterations of sleep related oscillations, we performed local field potential (LFP) and single unit recordings in rats for three months during their maturation. We found that while SWDs and spindles look similar in young, they become different with maturation and shift to appear in different brain states. Thus, despite being generated by the same network, they are likely two distinct manifestations of the thalamocortical activity. We show that while spindles are already mainly global oscillations, SWDs appear mainly only focally in young. They become capable to generalize later with maturation, when the out-of-focus brain regions develop a decreased inhibitory/excitatory balance. These results suggest that a hyperexcitable focus is not sufficient alone to drive generalized absence seizures. Importantly, we also found the gradual age dependent disappearance of sleep spindles coinciding with the simultaneous gradual emergence of spike and waves, which both could be reversed by the proper dosing of ethosuximide (ETX). Based on these observations we conclude that the absence seizure development might be a multi-step process, which might involve the functional impairment of cortical interneurons and network-level changes that negatively affect sleep quality.
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12
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Kim EH, Shim WH, Lee JS, Yoon HM, Ko TS, Yum MS. Altered Structural Network in Newly Onset Childhood Absence Epilepsy. J Clin Neurol 2020; 16:573-580. [PMID: 33029962 PMCID: PMC7541981 DOI: 10.3988/jcn.2020.16.4.573] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 05/15/2020] [Accepted: 05/15/2020] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND AND PURPOSE Recent quantitative neuroimaging studies of childhood absence epilepsy (CAE) have identified various structural abnormalities that might be involved in the onset of absence seizure and associated cognitive and behavioral functions. However, the neuroanatomical alterations specific to CAE remain unclear, and so this study investigated the regional alterations of brain structures associated with newly diagnosed CAE. METHODS Surface and volumetric magnetic resonance imaging data of patients with newly diagnosed CAE (n=18) and age-matched healthy controls (n=18) were analyzed using Free-Surfer software. A group comparison using analysis of covariance was performed with significance criteria of p<0.05 and p<0.01 in global and regional analyses, respectively. RESULTS Compared with control subjects, the patients with CAE had smaller total and regional volumes of cortical gray-matter (GM) in the right rostral middle frontal, right lateral orbitofrontal, and left rostral middle frontal regions, as well as in the right precentral, right superior, middle, left middle, and inferior temporal gyri. The cortex in the right posterior cingulate gyrus and left medial occipital region was significantly thicker in patients with CAE than in controls. CONCLUSIONS Patients with CAE showed a reduced bilateral frontotemporal cortical GM volume and an increased posterior medial cortical thickness, which are associated with the default mode network. These structural changes can be suggested as the neural basis of the absence seizures and neuropsychiatric comorbidities in CAE.
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Affiliation(s)
- Eun Hee Kim
- Department of Pediatrics, Sejong Chungnam National University Hospital, Chungnam National University College of Medicine, Sejong, Korea.,Department of Pediatrics, CHA Gangnam Medical Center, CHA University, Seoul, Korea
| | - Woo Hyun Shim
- Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Jin Seong Lee
- Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Hee Mang Yoon
- Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Tae Sung Ko
- Department of Pediatrics, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul, Korea
| | - Mi Sun Yum
- Department of Pediatrics, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul, Korea.
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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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Jiang W, Wu C, Xiang J, Miao A, Qiu W, Tang L, Huang S, Chen Q, Hu Z, Wang X. Dynamic Neuromagnetic Network Changes of Seizure Termination in Absence Epilepsy: A Magnetoencephalography Study. Front Neurol 2019; 10:703. [PMID: 31338058 PMCID: PMC6626921 DOI: 10.3389/fneur.2019.00703] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 06/14/2019] [Indexed: 11/28/2022] Open
Abstract
Objective: With increasing efforts devoted to investigating the generation and propagation mechanisms of spontaneous spike and wave discharges (SWDs), little attention has been paid to network mechanisms associated with termination patterns of SWDs to date. In the current study, we aimed to identify the frequency-dependent neural network dynamics during the offset of absence seizures. Methods: Fifteen drug-naïve patients with childhood absence epilepsy (CAE) were assessed with a 275-Channel Magnetoencephalography (MEG) system. MEG data were recorded during and between seizures at a sampling rate of 6,000 Hz and analyzed in seven frequency bands. Source localization was performed with accumulated source imaging. Granger causality analysis was used to evaluate effective connectivity networks of the entire brain at the source level. Results: At the low-frequency (1–80 Hz) bands, activities were predominantly distributed in the frontal cortical and parieto–occipito–temporal junction at the offset transition periods. The high-frequency oscillations (HFOs, 80–500 Hz) analysis indicated significant source localization in the medial frontal cortex and deep brain areas (mainly thalamus) during both the termination transition and interictal periods. Furthermore, an enhanced positive cortico–thalamic effective connectivity was observed around the discharge offset at all of the seven analyzed bands, the direction of which was primarily from various cortical regions to the thalamus. Conclusions: Seizure termination is a gradual process that involves both the cortices and the thalamus in CAE. Cortico–thalamic coupling is observed at the termination transition periods, and the cerebral cortex acts as the driving force.
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Affiliation(s)
- Wenwen Jiang
- Department of Neurology, The Affiliated Brain Hospital of Nanjing Medical University, Nanjing Medical University, Nanjing, China
| | - Caiyun Wu
- Department of Neurology, The Affiliated Brain Hospital of Nanjing Medical University, Nanjing Medical University, Nanjing, China
| | - Jing Xiang
- Division of Neurology, MEG Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Ailiang Miao
- Department of Neurology, The Affiliated Brain Hospital of Nanjing Medical University, Nanjing Medical University, Nanjing, China
| | - Wenchao Qiu
- Department of Neurology, The Affiliated Huai'an Hospital of Xuzhou Medical University, Huai'an, China
| | - Lu Tang
- Department of Neurology, The Affiliated Brain Hospital of Nanjing Medical University, Nanjing Medical University, Nanjing, China
| | - Shuyang Huang
- Department of Neurology, The Affiliated Brain Hospital of Nanjing Medical University, Nanjing Medical University, Nanjing, China
| | - Qiqi Chen
- MEG Center, The Affiliated Brain Hospital of Nanjing Medical University, Nanjing, China
| | - Zheng Hu
- Department of Neurology, Nanjing Children's Hospital, Nanjing, China
| | - Xiaoshan Wang
- Department of Neurology, The Affiliated Brain Hospital of Nanjing Medical University, Nanjing Medical University, Nanjing, China
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Mechanisms Underlying Aggressive Behavior Induced by Antiepileptic Drugs: Focus on Topiramate, Levetiracetam, and Perampanel. Behav Neurol 2018; 2018:2064027. [PMID: 30581496 PMCID: PMC6276511 DOI: 10.1155/2018/2064027] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 10/30/2018] [Indexed: 12/28/2022] Open
Abstract
Antiepileptic drugs (AEDs) are effective against seizures, but their use is often limited by adverse effects, among them psychiatric and behavioral ones including aggressive behavior (AB). Knowledge of the incidence, risk factors, and the underlying mechanisms of AB induced by AEDs may help to facilitate management and reduce the risk of such side effects. The exact incidence of AB as an adverse effect of AEDs is difficult to estimate, but frequencies up to 16% have been reported. Primarily, levetiracetam (LEV), perampanel (PER), and topiramate (TPM), which have diverse mechanisms of action, have been associated with AB. Currently, there is no evidence for a specific pharmacological mechanism solely explaining the increased incidence of AB with LEV, PER, and TPM. Serotonin (5-HT) and GABA, and particularly glutamate (via the AMPA receptor), seem to play key roles. Other mechanisms involve hormones, epigenetics, and “alternative psychosis” and related phenomena. Increased individual susceptibility due to an underlying neurological and/or a mental health disorder may further explain why people with epilepsy are at an increased risk of AB when using AEDs. Remarkably, AB may occur with a delay of weeks or months after start of treatment. Information to patients, relatives, and caregivers, as well as sufficient clinical follow-up, is crucial, and there is a need for further research to understand the complex relationship between AED mechanisms of action and the induction/worsening of AB.
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16
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Myers KA, Scheffer IE. Myoclonic absence seizures with complex gestural automatisms. Eur J Paediatr Neurol 2018; 22:532-535. [PMID: 29325826 DOI: 10.1016/j.ejpn.2017.12.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 11/15/2017] [Accepted: 12/09/2017] [Indexed: 10/18/2022]
Abstract
Epilepsy with myoclonic absences is a rare generalized epilepsy syndrome with distinctive seizures. Two unrelated children had mild developmental impairment and onset of myoclonic-absences at 3 and 8 years. Seizures were characterized by bilateral 3 Hz myoclonic jerks superimposed on tonic abduction of the upper limbs. Events lasted 10-60 s, and complex gestural automatisms were often observed; in one case, a boy undid his seatbelt and attempted to exit a moving vehicle. Post-ictally, both children immediately regained awareness without recollection of their actions. Ictal EEGs showed 3 Hz generalized spike-wave. Complex automatisms have not been described in myoclonic absence seizures. This generalized seizure type can be confused with focal seizures when these ictal behaviours occur.
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Affiliation(s)
- Kenneth A Myers
- Epilepsy Research Centre, Department of Medicine, The University of Melbourne, Austin Health, Heidelberg, Victoria, Australia
| | - Ingrid E Scheffer
- Epilepsy Research Centre, Department of Medicine, The University of Melbourne, Austin Health, Heidelberg, Victoria, Australia; Department of Paediatrics, The University of Melbourne, Parkville, Victoria, Australia; The Florey Institute of Neuroscience and Mental Health, Heidelberg, Victoria, Australia; Department of Neurology, Royal Children's Hospital, Parkville, Victoria, Australia.
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Exploring the origins of EEG motion artefacts during simultaneous fMRI acquisition: Implications for motion artefact correction. Neuroimage 2018; 173:188-198. [PMID: 29486322 PMCID: PMC5929889 DOI: 10.1016/j.neuroimage.2018.02.034] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 02/16/2018] [Indexed: 11/24/2022] Open
Abstract
Motion artefacts (MAs) are induced within EEG data collected simultaneously with fMRI when the subject's head rotates relative to the magnetic field. The effects of these artefacts have generally been ameliorated by removing periods of data during which large artefact voltages appear in the EEG traces. However, even when combined with other standard post-processing methods, this strategy does not remove smaller MAs which can dominate the neuronal signals of interest. A number of methods are therefore being developed to characterise the MA by measuring reference signals and then using these in artefact correction. These methods generally assume that the head and EEG cap, plus any attached sensors, form a rigid body which can be characterised by a standard set of six motion parameters. Here we investigate the motion of the head/EEG cap system to provide a better understanding of MAs. We focus on the reference layer artefact subtraction (RLAS) approach, as this allows measurement of a separate reference signal for each electrode that is being used to measure brain activity. Through a series of experiments on phantoms and subjects, we find that movement of the EEG cap relative to the phantom and skin on the forehead is relatively small and that this non-rigid body movement does not appear to cause considerable discrepancy in artefacts between the scalp and reference signals. However, differences in the amplitude of these signals is observed which may be due to differences in geometry of the system from which the reference signals are measured compared with the brain signals. In addition, we find that there is non-rigid body movement of the skull and skin which produces an additional MA component for a head shake, which is not present for a head nod. This results in a large discrepancy in the amplitude and temporal profile of the MA measured on the scalp and reference layer, reducing the efficacy of MA correction based on the reference signals. Together our data suggest that the efficacy of the correction of MA using any reference-based system is likely to differ for different types of head movement with head shake being the hardest to correct. This provides new information to inform the development of hardware and post-processing methods for removing MAs from EEG data acquired simultaneously with fMRI data.
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18
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Uncensored EEG: The role of DC potentials in neurobiology of the brain. Prog Neurobiol 2018; 165-167:51-65. [PMID: 29428834 DOI: 10.1016/j.pneurobio.2018.02.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 12/24/2017] [Accepted: 02/03/2018] [Indexed: 12/11/2022]
Abstract
Brain direct current (DC) potentials denote sustained shifts and slow deflections of cerebral potentials superimposed with conventional electroencephalography (EEG) waves and reflect alterations in the excitation level of the cerebral cortex and subcortical structures. Using galvanometers, such sustained displacement of the EEG baseline was recorded in the early days of EEG recordings. To stabilize the EEG baseline and eliminate artefacts, EEG was performed later by voltage amplifiers with high-pass filters that dismiss slow DC potentials. This left slow DC potential recordings as a neglected diagnostic source in the routine clinical setting over the last few decades. Brain DC waves may arise from physiological processes or pathological phenomena. Recordings of DC potentials are fundamental electro-clinical signatures of some neurological and psychological disorders and may serve as diagnostic, prognostic, and treatment monitoring tools. We here review the utility of both physiological and pathological brain DC potentials in different aspects of neurological and psychological disorders. This may enhance our understanding of the role of brain DC potentials and improve our fundamental clinical and research strategies for brain disorders.
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Wu C, Xiang J, Sun J, Huang S, Tang L, Miao A, Zhou Y, Chen Q, Hu Z, Wang X. Quantify neuromagnetic network changes from pre-ictal to ictal activities in absence seizures. Neuroscience 2017; 357:134-144. [PMID: 28576731 DOI: 10.1016/j.neuroscience.2017.05.038] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Revised: 05/23/2017] [Accepted: 05/23/2017] [Indexed: 10/19/2022]
Abstract
OBJECTIVE The cortico-thalamo-cortical network plays a key role in childhood absence epilepsy (CAE). However, the exact interaction between the cortex and the thalamus remains incompletely understood. This study aimed to investigate the dynamic changes of frequency-dependent neural networks during the initialization of absence seizures. METHODS Magnetoencephalography data from 14 patients with CAE were recorded during and between seizures at a sampling rate of 6000Hz and analyzed in seven frequency bands. Neuromagnetic sources were volumetrically scanned with accumulated source imaging. Effective connectivity networks of the entire brain, including the cortico-thalamo-cortical network, were evaluated at the source level through Granger causality analysis. RESULTS The low-frequency (1-80Hz) activities showed significant frontal cortical and parieto-occipito-temporal junction source localization around seizures. The high-frequency (80-250Hz) oscillations showed predominant activities consistently localized in deep brain areas and medial frontal cortex. The increased cortico-thalamic effective connectivity was observed around seizures in both low- and high-frequency ranges. The direction was predominantly from the cortex to the thalamus at the early time, although the cortex that drove connectivity varied among subjects. CONCLUSIONS The cerebral cortex plays a key role in driving the cortico-thalamic connections at the early portion of the initialization of absence seizures. The oscillatory activities in the thalamus could be triggered by networks from various regions in the cortex. SIGNIFICANCE The dynamic changes of neural network provide evidences that absence seizures are probably resulted from cortical initialized cortico-thalamic network.
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Affiliation(s)
- Caiyun Wu
- Department of Neurology, Nanjing Brain Hospital, Nanjing Medical University, Nanjing, Jiangsu 210029, China
| | - Jing Xiang
- MEG Center, Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45220, USA
| | - Jintao Sun
- Department of Neurology, Nanjing Brain Hospital, Nanjing Medical University, Nanjing, Jiangsu 210029, China
| | - Shuyang Huang
- Department of Neurology, Nanjing Brain Hospital, Nanjing Medical University, Nanjing, Jiangsu 210029, China
| | - Lu Tang
- Department of Neurology, Nanjing Brain Hospital, Nanjing Medical University, Nanjing, Jiangsu 210029, China
| | - Ailiang Miao
- Department of Neurology, Nanjing Brain Hospital, Nanjing Medical University, Nanjing, Jiangsu 210029, China
| | - Yuchen Zhou
- Department of Neurology, Nanjing Brain Hospital, Nanjing Medical University, Nanjing, Jiangsu 210029, China
| | - Qiqi Chen
- MEG Center, Nanjing Brain Hospital, Nanjing, Jiangsu 210029, China
| | - Zheng Hu
- Department of Neurology, Nanjing Children's Hospital, Nanjing, Jiangsu 210029, China
| | - Xiaoshan Wang
- Department of Neurology, Nanjing Brain Hospital, Nanjing Medical University, Nanjing, Jiangsu 210029, China.
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Vaudano AE, Olivotto S, Ruggieri A, Gessaroli G, De Giorgis V, Parmeggiani A, Veggiotti P, Meletti S. Brain correlates of spike and wave discharges in GLUT1 deficiency syndrome. NEUROIMAGE-CLINICAL 2016; 13:446-454. [PMID: 28116237 PMCID: PMC5233795 DOI: 10.1016/j.nicl.2016.12.026] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 11/04/2016] [Accepted: 12/19/2016] [Indexed: 11/25/2022]
Abstract
Purpose To provide imaging biomarkers of generalized spike-and-wave discharges (GSWD) in patients with GLUT1 deficiency syndrome (GLUT1DS). Methods Eighteen GLUT1DS patients with pathogenetic mutation in SLC2A1 gene were studied by means of Video-EEG simultaneously recorded with functional MRI (VideoEEG-fMRI). A control group of sex and age-matched patients affected by Genetic Generalized Epilepsy (GGE) with GSWD were investigated with the same protocol. Within and between groups comparison was performed as appropriated. For GLUT1DS, correlations analyses between the contrast of interest and the main clinical measurements were provided. Results EEG during fMRI revealed interictal GSWD in 10 GLUT1DS patients. Group-level analysis showed BOLD signal increases at the premotor cortex and putamen. With respect to GGE, GLUT1DS patients demonstrated increased neuronal activity in the putamen, precuneus, cingulate cortex, SMA and paracentral lobule. Whole-brain correlation analyses disclosed a linear relationship between the GSWD-related BOLD changes and the levels of glycorrhachia at diagnosis over the sensory-motor cortex and superior parietal lobuli. Conclusion The BOLD dynamics related to GSWD in GLUT1DS are substantially different from typical GGE showing the former an increased activity in the premotor-striatal network and a decrease in the thalamus. The revealed hemodynamic maps might represent imaging biomarkers of GLUT1DS, being potentially useful for a precocious diagnosis of this genetic disorder. First report describing the epilepsy-related hemodynamic patterns in GLUT1DS. The revealed BOLD maps can represent GLUT1DS imaging biomarkers. The premotor-striatal network generates the GSWD in GLUT1DS. The glycorrhachia at diagnosis influences the epilepsy-related BOLD maps.
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Affiliation(s)
- Anna Elisabetta Vaudano
- Department of Biomedical, Metabolic, and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy; N.O.C.S.A.E. Hospital, AUSL Modena, 41100 Modena, Italy
| | - Sara Olivotto
- Brain and Behavior Department, University of Pavia, Pavia, Italy
| | - Andrea Ruggieri
- Department of Biomedical, Metabolic, and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | | | | | - Antonia Parmeggiani
- Child Neurology and Psychiatry Unit, Policlinico S. Orsola-Malpighi, Bologna, Italy; Department of Medical and Surgical Sciences, University of Bologna, Italy
| | - Pierangelo Veggiotti
- Brain and Behavior Department, University of Pavia, Pavia, Italy; Department of Child Neurology and Psychiatry, "C. Mondino" National Neurological Institute, Pavia, Italy
| | - Stefano Meletti
- Department of Biomedical, Metabolic, and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy; N.O.C.S.A.E. Hospital, AUSL Modena, 41100 Modena, Italy
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Qiu W, Gao Y, Yu C, Miao A, Tang L, Huang S, Hu Z, Xiang J, Wang X. Structural Abnormalities in Childhood Absence Epilepsy: Voxel-Based Analysis Using Diffusion Tensor Imaging. Front Hum Neurosci 2016; 10:483. [PMID: 27733824 PMCID: PMC5039196 DOI: 10.3389/fnhum.2016.00483] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 09/12/2016] [Indexed: 11/30/2022] Open
Abstract
Purpose: Childhood absence epilepsy (CAE) is a common syndrome of idiopathic generalized epilepsy. However, little is known about the brain structural changes in this type of epilepsy, especially in the default mode network (DMN) regions. This study aims at using the diffusion tensor imaging (DTI) technique to quantify structural abnormalities of DMN nodes in CAE patients. Method: DTI data were acquired in 14 CAE patients (aged 8.64 ± 2.59 years, seven females and seven males) and 16 age- and sex-matched healthy controls. The data were analyzed using voxel-based analysis (VBA) and statistically compared between patients and controls. Pearson correlation was explored between altered DTI metrics and clinical parameters. The difference of brain volumes between patients and controls were also tested using unpaired t-test. Results: Patients showed significant increase of mean diffusivity (MD) and radial diffusivity (RD) in left medial prefrontal cortex (MPFC), and decrease of fractional anisotropy (FA) in left precuneus and axial diffusivity (AD) in both left MPFC and precuneus. In correlation analysis, MD value from left MPFC was positively associated with duration of epilepsy. Neither the disease duration nor the seizure frequency showed significant correlation with FA values. Between-group comparison of brain volumes got no significant difference. Conclusion: The findings indicate that structural impairments exist in DMN regions in children suffering from absence epilepsy and MD values positively correlate with epilepsy duration. This may contribute to understanding the pathological mechanisms of chronic neurological deficits and promote the development of new therapies for this disorder.
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Affiliation(s)
- Wenchao Qiu
- Department of Neurology, Nanjing Brain Hospital, Nanjing Medical University Nanjing, China
| | - Yuan Gao
- Department of Neurology, Nanjing Brain Hospital, Nanjing Medical University Nanjing, China
| | - Chuanyong Yu
- Department of Neurology, Nanjing Brain Hospital, Nanjing Medical University Nanjing, China
| | - Ailiang Miao
- Department of Neurology, Nanjing Brain Hospital, Nanjing Medical University Nanjing, China
| | - Lu Tang
- Department of Neurology, Nanjing Brain Hospital, Nanjing Medical University Nanjing, China
| | - Shuyang Huang
- Department of Neurology, Nanjing Brain Hospital, Nanjing Medical University Nanjing, China
| | - Zheng Hu
- Department of Neurology, Nanjing Children's Hospital Nanjing, China
| | - Jing Xiang
- MEG Center, Division of Neurology, Cincinnati Children's Hospital Medical Center Cincinnati, OH, USA
| | - Xiaoshan Wang
- Department of Neurology, Nanjing Brain Hospital, Nanjing Medical University Nanjing, China
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Taylor PN, Forsyth R. Heterogeneity of trans-callosal structural connectivity and effects on resting state subnetwork integrity may underlie both wanted and unwanted effects of therapeutic corpus callostomy. Neuroimage Clin 2016; 12:341-7. [PMID: 27547729 PMCID: PMC4983151 DOI: 10.1016/j.nicl.2016.07.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Revised: 07/16/2016] [Accepted: 07/23/2016] [Indexed: 12/03/2022]
Abstract
BACKGROUND The corpus callosum (CC) is the primary structure supporting interhemispheric connectivity in the brain. Partial or complete surgical callosotomy may be performed for the palliation of intractable epilepsy. A variety of disconnection syndromes are recognised after injury to or division of the CC however their mechanisms are poorly understood and their occurrence difficult to predict. We use novel high resolution structural connectivity analyses to demonstrate reasons for this poor predictability. METHODS Diffusion weighted MRI data from five healthy adult controls was subjected to novel high-resolution structural connectivity analysis. We simulated the effects of CC lesions of varying extents on the integrity of resting state subnetworks (RSNs). RESULTS There is substantial between-individual variation in patterns of CC connectivity. However in all individuals termination points of callosal connections mostly involve medial and superior sensory-motor areas. Superior temporal and lateral sensory-motor areas were not involved. Resting state networks showed selective vulnerability to simulated callosotomy of progressively greater anterior to posterior extent. The default mode network was most vulnerable followed by, in decreasing order: frontoparietal, limbic, somatomotor, ventral attention, dorsal attention and visual subnetworks. CONCLUSION Consideration of the selective vulnerability of resting state sub-networks, and of between-individual variability in connectivity patterns, sheds new light on the occurrence of both wanted and unwanted effects of callosotomy. We propose that beneficial effects (seizure reduction) relate to disruption of the default mode network, with unwanted "disconnection syndrome" effects due to disruption particularly of the somatomotor and frontoparietal RSNs. Our results may also explain why disconnection syndromes primary reflect lateralised sensory-motor problems (e.g. of limb movement) rather than midline function (e.g. tongue movement). Marked between-subject variation in callosal connectivity may underlie the poor predictability of effects of callosotomy. High resolution structural connectivity studies of this nature may be useful in pre-surgical planning of therapeutic callosotomy for intractable epilepsy.
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Affiliation(s)
- Peter Neal Taylor
- Institute of Neuroscience, Newcastle University, UK
- School of Computing Science, Newcastle University, UK
- Institute of Neurology, University College London, UK
| | - Rob Forsyth
- Institute of Neuroscience, Newcastle University, UK
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Abbott DF. Interictal Epileptiform Discharges Might Be More Likely During Particular Phases of Brain Activity. Front Neurol 2015; 6:253. [PMID: 26696954 PMCID: PMC4669409 DOI: 10.3389/fneur.2015.00253] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2015] [Accepted: 11/16/2015] [Indexed: 11/17/2022] Open
Affiliation(s)
- David F Abbott
- The Florey Institute of Neuroscience and Mental Health, Austin Hospital , Melbourne, VIC , Australia ; The University of Melbourne , Melbourne, VIC , Australia
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Are Absence Epilepsy and Nocturnal Frontal Lobe Epilepsy System Epilepsies of the Sleep/Wake System? Behav Neurol 2015; 2015:231676. [PMID: 26175547 PMCID: PMC4484558 DOI: 10.1155/2015/231676] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Revised: 04/13/2015] [Accepted: 05/05/2015] [Indexed: 12/05/2022] Open
Abstract
System epilepsy is an emerging concept interpreting major nonlesional epilepsies as epileptic dysfunctions of physiological systems. I extend here the concept of reflex epilepsy to epilepsies linked to input dependent physiological systems. Experimental and clinical reseach data were collected to create a coherent explanation of underlying pathomechanism in AE and NFLE. We propose that AE should be interpreted as epilepsy linked to the corticothalamic burst-firing mode of NREM sleep, released by evoked vigilance level oscillations characterized by reactive slow wave response. In the genetic variation of NFLE the ascending cholinergic arousal system plays an essential role being in strong relationship with a gain mutation of the nicotinic acethylcholin receptors, rendering the arousal system hyperexcitable. I try to provide a more unitary interpretation for the variable seizure manifestation integrating them as different degree of pathological arosuals and alarm reactions. As a supporting hypothesis the similarity between arousal parasomnias and FNLE is shown, underpinned by overlaping pathomechanism and shared familiarity, but without epileptic features. Lastly we propose that both AE and NFLE are system epilepsies of the sleep-wake system representing epileptic disorders of the antagonistic sleep/arousal network. This interpretation may throw new light on the pathomechanism of AE and NFLE.
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