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Leitch B. Molecular Mechanisms Underlying the Generation of Absence Seizures: Identification of Potential Targets for Therapeutic Intervention. Int J Mol Sci 2024; 25:9821. [PMID: 39337309 PMCID: PMC11432152 DOI: 10.3390/ijms25189821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2024] [Revised: 09/03/2024] [Accepted: 09/09/2024] [Indexed: 09/30/2024] Open
Abstract
Understanding the molecular mechanisms underlying the generation of absence seizures is crucial for developing effective, patient-specific treatments for childhood absence epilepsy (CAE). Currently, one-third of patients remain refractive to the antiseizure medications (ASMs), previously called antiepileptic drugs (AEDs), available to treat CAE. Additionally, these ASMs often produce serious side effects and can even exacerbate symptoms in some patients. Determining the precise cellular and molecular mechanisms directly responsible for causing this type of epilepsy has proven challenging as they appear to be complex and multifactorial in patients with different genetic backgrounds. Aberrant neuronal activity in CAE may be caused by several mechanisms that are not fully understood. Thus, dissecting the causal factors that could be targeted in the development of precision medicines without side effects remains a high priority and the ultimate goal in this field of epilepsy research. The aim of this review is to highlight our current understanding of potential causative mechanisms for absence seizure generation, based on the latest research using cutting-edge technologies. This information will be important for identifying potential targets for future therapeutic intervention.
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Affiliation(s)
- Beulah Leitch
- Department of Anatomy, School of Biomedical Sciences, Brain Health Research Centre, University of Otago, Dunedin 9054, New Zealand
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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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Sysoeva MV, Kuznetsova GD, Sysoev IV, Ngomba RT, Vinogradova LV, Grishchenko AA, van Rijn CM, van Luijtelaar G. NETWORK ANALYSIS REVEALS A ROLE OF THE HIPPOCAMPUS IN ABSENCE SEIZURES: THE EFFECTS OF A CANNABINOID AGONIST. Epilepsy Res 2023; 192:107135. [PMID: 37023553 DOI: 10.1016/j.eplepsyres.2023.107135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 02/27/2023] [Accepted: 03/30/2023] [Indexed: 04/04/2023]
Abstract
The role of the hippocampus (Hp) in absence epileptic networks and the effect of endocannabinoid system on this network remain enigmatic. Here, using adapted nonlinear Granger causality, we compared the differences in network strength in four intervals (baseline or interictal, preictal, ictal and postictal) in two hours before (Epoch 1) and six hours (epochs 2, 3 and 4) after the administration of three different doses of the endocannabinoid agonist WIN55,212-2 (WIN) or solvent. Local field potentials were recorded for eight hours in 23 WAG/Rij rats in the Frontal (FC), Parietal PC), Occipital Cortex (OC) and in the hippocampus (Hp). The four intervals were visually marked by an expert neurophysiologist and the strength of couplings between electrode pairs were calculated in both directions. Ictally, a strong decrease in coupling strength was found between Hp and FC, as well as a large increase bidirectionally between PC and FC and unidirectionally from FC and PC to OC, and from FC to Hp over all epochs. The highest dose of WIN increased the couplings strength from FC to Hp and from OC to PC during 4 and 2 hr respectively in all intervals, and decreased the FC to PC coupling strength postictally in epoch 2. A single rat showed generalized convulsive seizures after the highest dose: this rat shared not only coupling changes with the other rats in the same condition, but showed many more. WIN reduced SWD number in epoch 2 and 3, their mean duration increased in epochs 3 and 4. Conclusions:during SWDs FC and PC are strongly coupled and drive OC, while at the same time the influence of Hp to FC is diminished. The first is in agreement with the cortical focus theory, the latter demonstrates an involvement of the hippocampus in SWD occurrence and that ictally the hippocampal control of the cortico-thalamo-cortical system is lost. WIN causes dramatic network changes which have major consequences for the decrease of SWDs, the occurrence of convulsive seizures, and the normal cortico-cortical and cortico-hippocampal interactions.
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McCafferty C, Gruenbaum BF, Tung R, Li JJ, Zheng X, Salvino P, Vincent P, Kratochvil Z, Ryu JH, Khalaf A, Swift K, Akbari R, Islam W, Antwi P, Johnson EA, Vitkovskiy P, Sampognaro J, Freedman IG, Kundishora A, Depaulis A, David F, Crunelli V, Sanganahalli BG, Herman P, Hyder F, Blumenfeld H. Decreased but diverse activity of cortical and thalamic neurons in consciousness-impairing rodent absence seizures. Nat Commun 2023; 14:117. [PMID: 36627270 PMCID: PMC9832004 DOI: 10.1038/s41467-022-35535-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 12/08/2022] [Indexed: 01/12/2023] Open
Abstract
Absence seizures are brief episodes of impaired consciousness, behavioral arrest, and unresponsiveness, with yet-unknown neuronal mechanisms. Here we report that an awake female rat model recapitulates the behavioral, electroencephalographic, and cortical functional magnetic resonance imaging characteristics of human absence seizures. Neuronally, seizures feature overall decreased but rhythmic firing of neurons in cortex and thalamus. Individual cortical and thalamic neurons express one of four distinct patterns of seizure-associated activity, one of which causes a transient initial peak in overall firing at seizure onset, and another which drives sustained decreases in overall firing. 40-60 s before seizure onset there begins a decline in low frequency electroencephalographic activity, neuronal firing, and behavior, but an increase in higher frequency electroencephalography and rhythmicity of neuronal firing. Our findings demonstrate that prolonged brain state changes precede consciousness-impairing seizures, and that during seizures distinct functional groups of cortical and thalamic neurons produce an overall transient firing increase followed by a sustained firing decrease, and increased rhythmicity.
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Affiliation(s)
- Cian McCafferty
- Department of Neurology, Yale School of Medicine, New Haven, CT, 06520, USA
- Department of Anatomy & Neuroscience, University College Cork, Cork, Ireland
| | | | - Renee Tung
- Department of Neurology, Yale School of Medicine, New Haven, CT, 06520, USA
| | - Jing-Jing Li
- Department of Neurology, Yale School of Medicine, New Haven, CT, 06520, USA
| | - Xinyuan Zheng
- Department of Neurology, Yale School of Medicine, New Haven, CT, 06520, USA
| | - Peter Salvino
- Department of Neurology, Yale School of Medicine, New Haven, CT, 06520, USA
| | - Peter Vincent
- Department of Neurology, Yale School of Medicine, New Haven, CT, 06520, USA
| | - Zachary Kratochvil
- Department of Neurology, Yale School of Medicine, New Haven, CT, 06520, USA
| | - Jun Hwan Ryu
- Department of Neurology, Yale School of Medicine, New Haven, CT, 06520, USA
| | - Aya Khalaf
- Department of Neurology, Yale School of Medicine, New Haven, CT, 06520, USA
| | - Kohl Swift
- Department of Neurology, Yale School of Medicine, New Haven, CT, 06520, USA
| | - Rashid Akbari
- Department of Neurology, Yale School of Medicine, New Haven, CT, 06520, USA
| | - Wasif Islam
- Department of Neurology, Yale School of Medicine, New Haven, CT, 06520, USA
| | - Prince Antwi
- Department of Neurology, Yale School of Medicine, New Haven, CT, 06520, USA
| | - Emily A Johnson
- Department of Neurology, Yale School of Medicine, New Haven, CT, 06520, USA
| | - Petr Vitkovskiy
- Department of Neurology, Yale School of Medicine, New Haven, CT, 06520, USA
| | - James Sampognaro
- Department of Neurology, Yale School of Medicine, New Haven, CT, 06520, USA
| | - Isaac G Freedman
- Department of Neurology, Yale School of Medicine, New Haven, CT, 06520, USA
| | - Adam Kundishora
- Department of Neurology, Yale School of Medicine, New Haven, CT, 06520, USA
| | - Antoine Depaulis
- Univ. Grenoble Alpes, Inserm, U1216, Grenoble Institut Neurosciences, 38000, Grenoble, France
| | - François David
- Neuroscience Division, School of Bioscience, Cardiff University, Cardiff, UK
| | - Vincenzo Crunelli
- Neuroscience Division, School of Bioscience, Cardiff University, Cardiff, UK
| | - Basavaraju G Sanganahalli
- Magnetic Resonance Research Center, Yale University, New Haven, CT, 06520, USA
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, 06520, USA
- Department of Biomedical Engineering, Yale University, New Haven, CT, 06520, USA
| | - Peter Herman
- Magnetic Resonance Research Center, Yale University, New Haven, CT, 06520, USA
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, 06520, USA
- Department of Biomedical Engineering, Yale University, New Haven, CT, 06520, USA
| | - Fahmeed Hyder
- Magnetic Resonance Research Center, Yale University, New Haven, CT, 06520, USA
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT, 06520, USA
- Department of Biomedical Engineering, Yale University, New Haven, CT, 06520, USA
| | - Hal Blumenfeld
- Department of Neurology, Yale School of Medicine, New Haven, CT, 06520, USA.
- Magnetic Resonance Research Center, Yale University, New Haven, CT, 06520, USA.
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, 06520, USA.
- Department of Neurosurgery, Yale School of Medicine, New Haven, CT, 06520, USA.
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Kumar A, Lyzhko E, Hamid L, Srivastav A, Stephani U, Japaridze N. Neuronal networks underlying ictal and subclinical discharges in childhood absence epilepsy. J Neurol 2023; 270:1402-1415. [PMID: 36370186 PMCID: PMC9971098 DOI: 10.1007/s00415-022-11462-8] [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: 09/08/2022] [Revised: 10/25/2022] [Accepted: 10/26/2022] [Indexed: 11/13/2022]
Abstract
Childhood absence epilepsy (CAE), involves 3 Hz generalized spikes and waves discharges (GSWDs) on the electroencephalogram (EEG), associated with ictal discharges (seizures) with clinical symptoms and impairment of consciousness and subclinical discharges without any objective clinical symptoms or impairment of consciousness. This study aims to comparatively characterize neuronal networks underlying absence seizures and subclinical discharges, using source localization and functional connectivity (FC), to better understand the pathophysiological mechanism of these discharges. Routine EEG data from 12 CAE patients, consisting of 45 ictal and 42 subclinical discharges were selected. Source localization was performed using the exact low-resolution electromagnetic tomography (eLORETA) algorithm, followed by FC based on the imaginary part of coherency. FC based on the thalamus as the seed of interest showed significant differences between ictal and subclinical GSWDs (p < 0.05). For delta (1-3 Hz) and alpha bands (8-12 Hz), the thalamus displayed stronger connectivity towards other brain regions for ictal GSWDs as compared to subclinical GSWDs. For delta band, the thalamus was strongly connected to the posterior cingulate cortex (PCC), precuneus, angular gyrus, supramarginal gyrus, parietal superior, and occipital mid-region for ictal GSWDs. The strong connections of the thalamus with other brain regions that are important for consciousness, and with components of the default mode network (DMN) suggest the severe impairment of consciousness in ictal GSWDs. However, for subclinical discharges, weaker connectivity between the thalamus and these brain regions may suggest the prevention of impairment of consciousness. This may benefit future therapeutic targets and improve the management of CAE patients.
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Affiliation(s)
- Ami Kumar
- Department of Neuropediatrics, Children's Hospital, University Medical Center Schleswig-Holstein, University of Kiel, Kiel, Germany. .,Faculty of Mathematics and Natural Sciences, University of Kiel, Kiel, Germany. .,Department of Neurology, Columbia University Irving Medical Center, New York, USA.
| | - Ekaterina Lyzhko
- Department of Neuropediatrics, Children’s Hospital, University Medical Center Schleswig-Holstein, University of Kiel, Kiel, Germany
| | - Laith Hamid
- Institute of Medical Psychology and Medical Sociology, University of Kiel, Kiel, Germany ,Department of Psychiatry and Psychotherapy, Jena University Hospital, Jena, Germany
| | - Anand Srivastav
- Faculty of Mathematics and Natural Sciences, University of Kiel, Kiel, Germany
| | - Ulrich Stephani
- Department of Neuropediatrics, Children’s Hospital, University Medical Center Schleswig-Holstein, University of Kiel, Kiel, Germany
| | - Natia Japaridze
- Department of Neuropediatrics, Children’s Hospital, University Medical Center Schleswig-Holstein, University of Kiel, Kiel, Germany
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Sarkisova K, van Luijtelaar G. The impact of early-life environment on absence epilepsy and neuropsychiatric comorbidities. IBRO Neurosci Rep 2022; 13:436-468. [PMID: 36386598 PMCID: PMC9649966 DOI: 10.1016/j.ibneur.2022.10.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 10/30/2022] [Accepted: 10/31/2022] [Indexed: 11/11/2022] Open
Abstract
This review discusses the long-term effects of early-life environment on epileptogenesis, epilepsy, and neuropsychiatric comorbidities with an emphasis on the absence epilepsy. The WAG/Rij rat strain is a well-validated genetic model of absence epilepsy with mild depression-like (dysthymia) comorbidity. Although pathologic phenotype in WAG/Rij rats is genetically determined, convincing evidence presented in this review suggests that the absence epilepsy and depression-like comorbidity in WAG/Rij rats may be governed by early-life events, such as prenatal drug exposure, early-life stress, neonatal maternal separation, neonatal handling, maternal care, environmental enrichment, neonatal sensory impairments, neonatal tactile stimulation, and maternal diet. The data, as presented here, indicate that some early environmental events can promote and accelerate the development of absence seizures and their neuropsychiatric comorbidities, while others may exert anti-epileptogenic and disease-modifying effects. The early environment can lead to phenotypic alterations in offspring due to epigenetic modifications of gene expression, which may have maladaptive consequences or represent a therapeutic value. Targeting DNA methylation with a maternal methyl-enriched diet during the perinatal period appears to be a new preventive epigenetic anti-absence therapy. A number of caveats related to the maternal methyl-enriched diet and prospects for future research are discussed.
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Affiliation(s)
- Karine Sarkisova
- Institute of Higher Nervous Activity and Neurophysiology of Russian Academy of Sciences, Butlerova str. 5a, Moscow 117485, Russia
| | - Gilles van Luijtelaar
- Donders Institute for Brain, Cognition, and Behavior, Donders Center for Cognition, Radboud University, Nijmegen, PO Box 9104, 6500 HE Nijmegen, the Netherlands
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Maki Y, Natsume J, Ito Y, Okai Y, Bagarinao E, Yamamoto H, Ogaya S, Takeuchi T, Fukasawa T, Sawamura F, Mitsumatsu T, Maesawa S, Saito R, Takahashi Y, Kidokoro H. Involvement of the Thalamus, Hippocampus, and Brainstem in Hypsarrhythmia of West Syndrome: Simultaneous Recordings of Electroencephalography and fMRI Study. AJNR Am J Neuroradiol 2022; 43:1502-1507. [PMID: 36137665 PMCID: PMC9575537 DOI: 10.3174/ajnr.a7646] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 07/27/2022] [Indexed: 01/26/2023]
Abstract
BACKGROUND AND PURPOSE West syndrome is a developmental and epileptic encephalopathy characterized by epileptic spasms, neurodevelopmental regression, and a specific EEG pattern called hypsarrhythmia. Our aim was to investigate the brain activities related to hypsarrhythmia at onset and focal epileptiform discharges in the remote period in children with West syndrome using simultaneous electroencephalography and fMRI recordings. MATERIALS AND METHODS Fourteen children with West syndrome underwent simultaneous electroencephalography and fMRI at the onset of West syndrome. Statistically significant blood oxygen level-dependent responses related to hypsarrhythmia were analyzed using an event-related design of 4 hemodynamic response functions with peaks at 3, 5, 7, and 9 seconds after the onset of each event. Six of 14 children had focal epileptiform discharges after treatment and underwent simultaneous electroencephalography and fMRI from 12 to 25 months of age. RESULTS At onset, positive blood oxygen level-dependent responses were seen in the brainstem (14/14 patients), thalami (13/14), basal ganglia (13/14), and hippocampi (13/14), in addition to multiple cerebral cortices. Group analysis using hemodynamic response functions with peaks at 3, 5, and 7 seconds showed positive blood oxygen level-dependent responses in the brainstem, thalamus, and hippocampus, while positive blood oxygen level-dependent responses in multiple cerebral cortices were seen using hemodynamic response functions with peaks at 5 and 7 seconds. In the remote period, 3 of 6 children had focal epileptiform discharge-related positive blood oxygen level-dependent responses in the thalamus, hippocampus, and brainstem. CONCLUSIONS Positive blood oxygen level-dependent responses with hypsarrhythmia appeared in the brainstem, thalamus, and hippocampus on earlier hemodynamic response functions than the cerebral cortices, suggesting the propagation of epileptogenic activities from the deep brain structures to the neocortices. Activation of the hippocampus, thalamus, and brainstem was still seen in half of the patients with focal epileptiform discharges after adrenocorticotropic hormone therapy.
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Affiliation(s)
- Y Maki
- From the Departments of Pediatrics (Y.M., J.N., Y.I., Y.O., H.Y., F.S., T.M., Y.T., H.K.)
| | - J Natsume
- From the Departments of Pediatrics (Y.M., J.N., Y.I., Y.O., H.Y., F.S., T.M., Y.T., H.K.)
- Developmental Disability Medicine (J.N.)
- Brain and Mind Research Center (J.N., Y.I., Y.O., E.B., H.Y., S.M., H.K.), Nagoya University, Nagoya, Japan
| | - Y Ito
- From the Departments of Pediatrics (Y.M., J.N., Y.I., Y.O., H.Y., F.S., T.M., Y.T., H.K.)
- Brain and Mind Research Center (J.N., Y.I., Y.O., E.B., H.Y., S.M., H.K.), Nagoya University, Nagoya, Japan
- Department of Pediatrics (Y.I.), Aichi Prefectural Mikawa Aoitori Medical and Rehabilitation Center, Okazaki, Japan
| | - Y Okai
- From the Departments of Pediatrics (Y.M., J.N., Y.I., Y.O., H.Y., F.S., T.M., Y.T., H.K.)
- Brain and Mind Research Center (J.N., Y.I., Y.O., E.B., H.Y., S.M., H.K.), Nagoya University, Nagoya, Japan
- Department of Pediatric Neurology (Y.O.), Toyota Municipal Child Development Center, Toyota, Japan
| | - E Bagarinao
- Brain and Mind Research Center (J.N., Y.I., Y.O., E.B., H.Y., S.M., H.K.), Nagoya University, Nagoya, Japan
| | - H Yamamoto
- From the Departments of Pediatrics (Y.M., J.N., Y.I., Y.O., H.Y., F.S., T.M., Y.T., H.K.)
- Brain and Mind Research Center (J.N., Y.I., Y.O., E.B., H.Y., S.M., H.K.), Nagoya University, Nagoya, Japan
| | - S Ogaya
- Department of Pediatric Neurology (S.O.), Aichi Developmental Disability Center Central Hospital, Kasugai, Japan
| | - T Takeuchi
- Department of Pediatrics (T.T.), Japanese Red Cross Nagoya First Hospital
| | - T Fukasawa
- Nagoya, Japan; and Department of Pediatrics (T.F.), Anjo Kosei Hospital, Anjo, Japan
| | - F Sawamura
- From the Departments of Pediatrics (Y.M., J.N., Y.I., Y.O., H.Y., F.S., T.M., Y.T., H.K.)
| | - T Mitsumatsu
- From the Departments of Pediatrics (Y.M., J.N., Y.I., Y.O., H.Y., F.S., T.M., Y.T., H.K.)
| | - S Maesawa
- Neurosurgery (S.M., R.S.), Nagoya University Graduate School of Medicine, Nagoya, Japan
- Brain and Mind Research Center (J.N., Y.I., Y.O., E.B., H.Y., S.M., H.K.), Nagoya University, Nagoya, Japan
| | - R Saito
- Neurosurgery (S.M., R.S.), Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Y Takahashi
- From the Departments of Pediatrics (Y.M., J.N., Y.I., Y.O., H.Y., F.S., T.M., Y.T., H.K.)
| | - H Kidokoro
- From the Departments of Pediatrics (Y.M., J.N., Y.I., Y.O., H.Y., F.S., T.M., Y.T., H.K.)
- Brain and Mind Research Center (J.N., Y.I., Y.O., E.B., H.Y., S.M., H.K.), Nagoya University, Nagoya, Japan
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Zillgitt AJ, Haykal MA, Chehab A, Staudt MD. Centromedian thalamic neuromodulation for the treatment of idiopathic generalized epilepsy. Front Hum Neurosci 2022; 16:907716. [PMID: 35992953 PMCID: PMC9381751 DOI: 10.3389/fnhum.2022.907716] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 07/13/2022] [Indexed: 11/20/2022] Open
Abstract
Idiopathic generalized epilepsy (IGE) is a common type of epilepsy and despite an increase in the number of available anti-seizure medications, approximately 20–30% of people with IGE continue to experience seizures despite adequate medication trials. Unlike focal epilepsy, resective surgery is not a viable treatment option for IGE; however, neuromodulation may be an effective surgical treatment for people with IGE. Thalamic stimulation through deep brain stimulation (DBS) and responsive neurostimulation (RNS) have been explored for the treatment of generalized and focal epilepsies. Although the data regarding DBS and RNS in IGE is limited to case reports and case series, the results of the published studies have been promising. The current manuscript will review the published literature of DBS and RNS within the centromedian nucleus of the thalamus for the treatment of IGE, as well as highlight an illustrative case.
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Affiliation(s)
- Andrew J. Zillgitt
- Department of Neurology, Beaumont Health Adult Comprehensive Epilepsy Center, Neuroscience Center, Royal Oak, MI, United States
| | - M. Ayman Haykal
- Department of Neurology, Beaumont Health Adult Comprehensive Epilepsy Center, Neuroscience Center, Royal Oak, MI, United States
| | - Ahmad Chehab
- Department of Neurosurgery, Beaumont Neuroscience Center, Royal Oak, MI, United States
| | - Michael D. Staudt
- Department of Neurosurgery, Beaumont Neuroscience Center, Royal Oak, MI, United States
- Department of Neurosurgery, Oakland University William Beaumont School of Medicine, Rochester, MI, United States
- Michigan Head and Spine Institute, Southfield, MI, United States
- *Correspondence: Michael D. Staudt,
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Chen G, Hu J, Ran H, Nie L, Tang W, Li X, Li Q, He Y, Liu J, Song G, Xu G, Liu H, Zhang T. Alterations of Cerebral Perfusion and Functional Connectivity in Children With Idiopathic Generalized Epilepsy. Front Neurosci 2022; 16:918513. [PMID: 35769697 PMCID: PMC9236200 DOI: 10.3389/fnins.2022.918513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 05/25/2022] [Indexed: 12/02/2022] Open
Abstract
Background Studies have demonstrated that adults with idiopathic generalized epilepsy (IGE) have functional abnormalities; however, the neuropathological pathogenesis differs between adults and children. This study aimed to explore alterations in the cerebral blood flow (CBF) and functional connectivity (FC) to comprehensively elucidate the neuropathological mechanisms of IGE in children. Methods We obtained arterial spin labeling (ASL) and resting state functional magnetic resonance imaging data of 28 children with IGE and 35 matched controls. We used ASL to determine differential CBF regions in children with IGE. A seed-based whole-brain FC analysis was performed for regions with significant CBF changes. The mean CBF and FC of brain areas with significant group differences was extracted, then its correlation with clinical variables in IGE group was analyzed by using Pearson correlation analysis. Results Compared to controls, children with IGE had CBF abnormalities that were mainly observed in the right middle temporal gyrus, right middle occipital gyrus (MOG), right superior frontal gyrus (SFG), left inferior frontal gyrus (IFG), and triangular part of the left IFG (IFGtriang). We observed that the FC between the left IFGtriang and calcarine fissure (CAL) and that between the right MOG and bilateral CAL were decreased in children with IGE. The CBF in the right SFG was correlated with the age at IGE onset. FC in the left IFGtriang and left CAL was correlated with the IGE duration. Conclusion This study found that CBF and FC were altered simultaneously in the left IFGtriang and right MOG of children with IGE. The combination of CBF and FC may provide additional information and insight regarding the pathophysiology of IGE from neuronal and vascular integration perspectives.
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Middlebrooks EH, He X, Grewal SS, Keller SS. Neuroimaging and thalamic connectomics in epilepsy neuromodulation. Epilepsy Res 2022; 182:106916. [PMID: 35367691 DOI: 10.1016/j.eplepsyres.2022.106916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 03/05/2022] [Accepted: 03/27/2022] [Indexed: 11/03/2022]
Abstract
Neuromodulation is an increasingly utilized therapy for the treatment of people with drug-resistant epilepsy. To date, the most common and effective target has been the thalamus, which is known to play a key role in multiple forms of epilepsy. Neuroimaging has facilitated rapid developments in the understanding of functional targets, surgical and programming techniques, and the effects of thalamic stimulation. In this review, the role of neuroimaging in neuromodulation is explored. First, the structural and functional changes of the thalamus in common epilepsy syndromes are discussed as the rationale for neuromodulation of the thalamus. Next, methods for imaging different thalamic nuclei are presented, as well as rationale for the need of direct surgical targeting rather than reliance on traditional stereotactic coordinates. Lastly, we discuss the potential role of neuroimaging in assessing the effects of thalamic stimulation and as a potential biomarker for neuromodulation outcomes.
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Affiliation(s)
- Erik H Middlebrooks
- Department of Radiology, Mayo Clinic, Jacksonville, FL, USA; Department of Neurosurgery, Mayo Clinic, Jacksonville, FL, USA.
| | - Xiaosong He
- Department of Psychology, University of Science and Technology of China, Hefei, Anhui, China
| | | | - Simon S Keller
- Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, UK
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11
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Pretreatment Topological Disruptions of Whole-brain Networks Exist in Childhood Absence Epilepsy: A Resting-state EEG-fMRI Study. Epilepsy Res 2022; 182:106909. [DOI: 10.1016/j.eplepsyres.2022.106909] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Revised: 02/24/2022] [Accepted: 03/13/2022] [Indexed: 11/19/2022]
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12
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The role of thalamic nuclei in genetic generalized epilepsies. Epilepsy Res 2022; 182:106918. [DOI: 10.1016/j.eplepsyres.2022.106918] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 03/11/2022] [Accepted: 03/28/2022] [Indexed: 01/10/2023]
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13
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Chen L, Rao B, Li S, Gao L, Xie Y, Dai X, Fu K, Peng XZ, Xu H. Altered Effective Connectivity Measured by Resting-State Functional Magnetic Resonance Imaging in Posterior Parietal-Frontal-Striatum Circuit in Patients With Disorder of Consciousness. Front Neurosci 2022; 15:766633. [PMID: 35153656 PMCID: PMC8830329 DOI: 10.3389/fnins.2021.766633] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Accepted: 12/13/2021] [Indexed: 11/30/2022] Open
Abstract
Objective Disorder of consciousness (DoC) resulting from severe brain injury is characterized by cortical and subcortical dysconnectivity. However, research on seed-based effective connectivity (EC) of DoC might be questioned as to the heterogeneity of prior assumptions. Methods Functional MRI data of 16 DoC patients and 16 demographically matched healthy individuals were analyzed. Revised coma recovery scale (CRS-R) scores of patients were acquired. Seed-based d mapping permutation of subject images (SDM-PSI) of meta-analysis was performed to quantitatively synthesize results from neuroimaging studies that evaluated resting-state functional activity in DoC patients. Spectral dynamic causal modeling (spDCM) was used to assess how EC altered between brain regions in DoC patients compared to healthy individuals. Results We found increased effective connectivity in left striatum and decreased effective connectivity in bilateral precuneus (preCUN)/posterior cingulate cortex (PCC), bilateral midcingulate cortex and left middle frontal gyrus in DoC compared with the healthy controls. The resulting pattern of interaction in DoC indicated disrupted connection and disturbance of posterior parietal-frontal-striatum, and reduced self-inhibition of preCUN/PCC. The strength of self-inhibition of preCUN/PCC was negatively correlated with the total score of CRS-R. Conclusion This impaired EC in DoC may underlie disruption in the posterior parietal-frontal-striatum circuit, particularly damage to the cortico-striatal connection and possible loss of preCUN/PCC function as the main regulatory hub.
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Affiliation(s)
- Linglong Chen
- Department of Radiology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Bo Rao
- Department of Radiology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Sirui Li
- Department of Radiology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Lei Gao
- Department of Radiology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Yu Xie
- Department of Neurology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Xuan Dai
- Department of Neurosurgery, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Kai Fu
- Department of Neurosurgery, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Xu Zhi Peng
- Department of Neurology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Haibo Xu
- Department of Radiology, Zhongnan Hospital of Wuhan University, Wuhan, China
- *Correspondence: Haibo Xu,
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14
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Tenney JR, Williamson BJ, Kadis DS. Cross-Frequency Coupling in Childhood Absence Epilepsy. Brain Connect 2021; 12:489-496. [PMID: 34405685 DOI: 10.1089/brain.2021.0119] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Objective: Absence seizures are the prototypic primarily generalized seizures, but there is incomplete understanding regarding their generation and maintenance. A core network for absence seizures has been defined, including focal cortical and thalamic regions that have frequency-dependent interactions. The purpose of this study was to investigate within-frequency coupling and cross-frequency coupling (CFC) during human absence seizures, to identify key regions (hubs) within the absence network that contribute to propagation and maintenance. Methods: Thirteen children with new-onset and untreated childhood absence epilepsy had over 60 typical absence seizures during both electroencephalography-functional magnetic resonance imaging (fMRI) and magnetoencephalography (MEG) recordings. The spatial map of the ictal network was defined using fMRI and used as prior information for MEG connectivity. A multilayer network approach was used to investigate within-frequency coupling and CFC for canonical frequency bands. A rigorous null-modeling approach was used to determine connections outside the noise floor. Results: Strong coupling between beta and gamma frequencies, within the left frontal cortex, and between the left frontal and right parietal regions was observed. There was also strong connectivity between left frontal and right parietal nodes within the gamma band. Multilayer versatility analysis identified a cluster of network hubs in the left frontal region. Interpretation: Cortical regions commonly identified as being critical for absence seizure generation (frontal cortex, precuneus) have strong CFC and within-frequency coupling between beta and gamma bands. As nonpharmacologic treatments, such as neuromodulation, become available for generalized epilepsies, detailed mechanistic understanding of how "diffuse" seizures are generated and maintained will be necessary to provide optimal outcomes.
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Affiliation(s)
- Jeffrey R Tenney
- Division of Neurology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Brady J Williamson
- Department of Radiology, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Darren S Kadis
- Neurosciences and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Physiology, University of Toronto, Toronto, Ontario, Canada
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15
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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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16
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Altered peri-seizure EEG microstate dynamics in patients with absence epilepsy. Seizure 2021; 88:15-21. [PMID: 33799135 DOI: 10.1016/j.seizure.2021.03.020] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Revised: 03/20/2021] [Accepted: 03/20/2021] [Indexed: 10/21/2022] Open
Abstract
OBJECTIVE To investigate whether the parameters of EEG microstates changed before and after an absence seizure episode. METHODS AE patients with a current high frequency of seizures were included (n=21). Each included subject underwent a two-hour and 19-channel video EEG examination. Five epochs of 10-second EEG data in interictal, pre-seizure, and post-seizure states were collected from each AE patient. Five 10-second resting-state EEG epochs from sex- and age-matched HCs who reported no history of neurological or psychiatric disorders and visited the hospital for routine physical examinations were collected. Microstate analysis and source localization of microstates were performed using the LORETA KEY tool. RESULTS Compared with the resting-state EEGs of HCs, the interictal EEGs of AE patients showed a higher relative transition rate from microstates B to D (p<0.05). From interictal to pre-seizure EEG, the total time ratio of microstate C and the occurrence of microstate B decreased significantly, while the duration of microstate B increased significantly (p<0.05). Compared with pre-seizure EEGs, microstate C in post-seizure EEGs showed a significantly downregulated total time percentage and occurrence (p<0.05). The source localization of each microstate in each condition also varied and showed spatial recovery tends from pre- to post-seizure states. CONCLUSION Altered EEG microstate dynamics exist between inter-ictal EEGs of AE patients and resting-state EEGs of HCs and between pre- and post-seizure EEGs in AE patients. The EEG microstates of epileptic patients before and after absence seizures are characterized by a "slowdown" in transitions between microstates. Microstates might be used as an index to evaluate the temporal and spatial recovery process of absence seizures in AE.
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17
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Arnal-Real C, Mahmoudzadeh M, Manoochehri M, Nourhashemi M, Wallois F. What Triggers the Interictal Epileptic Spike? A Multimodal Multiscale Analysis of the Dynamic of Synaptic and Non-synaptic Neuronal and Vascular Compartments Using Electrical and Optical Measurements. Front Neurol 2021; 12:596926. [PMID: 33643187 PMCID: PMC7907164 DOI: 10.3389/fneur.2021.596926] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 01/21/2021] [Indexed: 11/20/2022] Open
Abstract
Interictal spikes (IISs) may result from a disturbance of the intimate functional balance between various neuronal (synaptic and non-synaptic), vascular, and metabolic compartments. To better characterize the complex interactions within these compartments at different scales we developed a simultaneous multimodal-multiscale approach and measure their activity around the time of the IIS. We performed such measurements in an epileptic rat model (n = 43). We thus evaluated (1) synaptic dynamics by combining electrocorticography and multiunit activity recording in the time and time-frequency domain, (2) non-synaptic dynamics by recording modifications in light scattering induced by changes in the membrane configuration related to cell activity using the fast optical signal, and (3) vascular dynamics using functional near-infrared spectroscopy and, independently but simultaneously to the electrocorticography, the changes in cerebral blood flow using diffuse correlation spectroscopy. The first observed alterations in the measured signals occurred in the hemodynamic compartments a few seconds before the peak of the IIS. These hemodynamic changes were followed by changes in coherence and then synchronization between the deep and superficial neural networks in the 1 s preceding the IIS peaks. Finally, changes in light scattering before the epileptic spikes suggest a change in membrane configuration before the IIS. Our multimodal, multiscale approach highlights the complexity of (1) interactions between the various neuronal, vascular, and extracellular compartments, (2) neural interactions between various layers, (3) the synaptic mechanisms (coherence and synchronization), and (4) non-synaptic mechanisms that take place in the neuronal network around the time of the IISs in a very specific cerebral hemodynamic environment.
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Affiliation(s)
- Cristian Arnal-Real
- Inserm U1105, GRAMFC, CURS, Université de Picardie Jules Verne, Amiens, France
| | - Mahdi Mahmoudzadeh
- Inserm U1105, GRAMFC, CURS, Université de Picardie Jules Verne, Amiens, France
| | - Mana Manoochehri
- Inserm U1105, GRAMFC, CURS, Université de Picardie Jules Verne, Amiens, France
| | - Mina Nourhashemi
- Inserm U1105, GRAMFC, CURS, Université de Picardie Jules Verne, Amiens, France
| | - Fabrice Wallois
- Inserm U1105, GRAMFC, CURS, Université de Picardie Jules Verne, Amiens, France
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18
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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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19
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Zhang T, Zhang Y, Ren J, Yang C, Zhou H, Li L, Lei D, Gong Q, Zhou D, Yang T. Aberrant basal ganglia-thalamo-cortical network topology in juvenile absence epilepsy: A resting-state EEG-fMRI study. Seizure 2020; 84:78-83. [PMID: 33307464 DOI: 10.1016/j.seizure.2020.11.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 11/22/2020] [Accepted: 11/28/2020] [Indexed: 02/05/2023] Open
Abstract
PURPOSE The underlying pathophysiology of juvenile absence epilepsy (JAE) is unclear. Since cortical and subcortical brain regions are thought to be altered in genetic generalized epilepsy, the present study examined the resting-state functional network topology of the same regions in JAE. METHODS Electroencephalography and functional magnetic resonance imaging (EEG-fMRI) were performed on 18 JAE patients and 28 healthy controls (HCs). The topology of functional networks was analyzed using the graph-theoretic method. Both global and nodal network parameters were calculated, and parameters differing significantly between the two groups were correlated with clinical variables. RESULTS Both JAE patients and HCs had small-world functional network topological architectures. However, JAE patients showed higher values for the global parameters of clustering coefficient (Cp) and normalized characteristic path length (Lambda). At the nodal level, patients exhibited greater centrality at widespread cortices, including the left superior parietal gyrus, right superior temporal gyrus, right orbital part of middle frontal gyrus and bilateral supplementary motor area. Conversely, patients showed decreased nodal centrality predominantly in the limbic network, left thalamus and right caudate nucleus. Degree centrality in the right hippocampus and betweenness centrality in the right caudate nucleus positively correlated with epilepsy duration. CONCLUSION The global functional network of JAE shows small-world properties, but tends to be regular with higher segregation and lower integration. Regions in the basal ganglia-thalamo-cortical network have aberrant nodal centrality. The hippocampus and caudate nucleus may reorganize as epilepsy progresses. Our findings indicate the pathogenesis and compensatory mechanisms to seizure attacks and cognitive deficits of JAE.
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Affiliation(s)
- Tianyu Zhang
- Department of Neurology, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Yingying Zhang
- Department of Neurology, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Jiechuan Ren
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Cheng Yang
- Huaxi MR Research Center, Department of Radiology, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Huanyu Zhou
- Department of Neurology, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Lei Li
- Huaxi MR Research Center, Department of Radiology, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Du Lei
- Huaxi MR Research Center, Department of Radiology, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Qiyong Gong
- Huaxi MR Research Center, Department of Radiology, West China Hospital, Sichuan University, Chengdu, Sichuan, China.
| | - Dong Zhou
- Department of Neurology, West China Hospital, Sichuan University, Chengdu, Sichuan, China.
| | - Tianhua Yang
- Department of Neurology, West China Hospital, Sichuan University, Chengdu, Sichuan, China.
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20
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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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21
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Forrester M, Crofts JJ, Sotiropoulos SN, Coombes S, O'Dea RD. The role of node dynamics in shaping emergent functional connectivity patterns in the brain. Netw Neurosci 2020; 4:467-483. [PMID: 32537537 PMCID: PMC7286301 DOI: 10.1162/netn_a_00130] [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: 07/02/2019] [Accepted: 01/31/2020] [Indexed: 11/07/2022] Open
Abstract
The contribution of structural connectivity to functional brain states remains poorly understood. We present a mathematical and computational study suited to assess the structure–function issue, treating a system of Jansen–Rit neural mass nodes with heterogeneous structural connections estimated from diffusion MRI data provided by the Human Connectome Project. Via direct simulations we determine the similarity of functional (inferred from correlated activity between nodes) and structural connectivity matrices under variation of the parameters controlling single-node dynamics, highlighting a nontrivial structure–function relationship in regimes that support limit cycle oscillations. To determine their relationship, we firstly calculate network instabilities giving rise to oscillations, and the so-called ‘false bifurcations’ (for which a significant qualitative change in the orbit is observed, without a change of stability) occurring beyond this onset. We highlight that functional connectivity (FC) is inherited robustly from structure when node dynamics are poised near a Hopf bifurcation, whilst near false bifurcations, and structure only weakly influences FC. Secondly, we develop a weakly coupled oscillator description to analyse oscillatory phase-locked states and, furthermore, show how the modular structure of FC matrices can be predicted via linear stability analysis. This study thereby emphasises the substantial role that local dynamics can have in shaping large-scale functional brain states. Patterns of oscillation across the brain arise because of structural connections between brain regions. However, the type of oscillation at a site may also play a contributory role. We focus on an idealised model of a neural mass network, coupled using estimates of structural connections obtained via tractography on Human Connectome Project MRI data. Using a mixture of computational and mathematical techniques, we show that functional connectivity is inherited most strongly from structural connectivity when the network nodes are poised at a Hopf bifurcation. However, beyond the onset of this oscillatory instability a phase-locked network state can undergo a false bifurcation, and structural connectivity only weakly influences functional connectivity. This highlights the important effect that local dynamics can have on large-scale brain states.
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Affiliation(s)
- Michael Forrester
- Centre for Mathematical Medicine and Biology, School of Mathematical Sciences, University of Nottingham, Nottingham, UK
| | - Jonathan J Crofts
- Department of Physics and Mathematics, School of Science and Technology, Nottingham Trent University, Nottingham, UK
| | - Stamatios N Sotiropoulos
- Sir Peter Mansfield Imaging Centre, Queen's Medical Centre, University of Nottingham, Nottingham, UK
| | - Stephen Coombes
- Centre for Mathematical Medicine and Biology, School of Mathematical Sciences, University of Nottingham, Nottingham, UK
| | - Reuben D O'Dea
- Centre for Mathematical Medicine and Biology, School of Mathematical Sciences, University of Nottingham, Nottingham, UK
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22
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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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Ratcliffe C, Wandschneider B, Baxendale S, Thompson P, Koepp MJ, Caciagli L. Cognitive Function in Genetic Generalized Epilepsies: Insights From Neuropsychology and Neuroimaging. Front Neurol 2020; 11:144. [PMID: 32210904 PMCID: PMC7076110 DOI: 10.3389/fneur.2020.00144] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Accepted: 02/10/2020] [Indexed: 12/17/2022] Open
Abstract
Genetic generalized epilepsies (GGE), previously called idiopathic generalized epilepsies, constitute about 20% of all epilepsies, and include childhood absence epilepsy, juvenile absence epilepsy, juvenile myoclonic epilepsy, and epilepsy with generalized tonic-clonic seizures alone (CAE, JAE, JME, and GGE-GTCS, respectively). GGE are characterized by high heritability, likely underlain by polygenetic mechanisms, which may relate to atypical neurodevelopmental trajectories. Age of onset ranges from pre-school years, for CAE, to early adulthood for GGE-GTCS. Traditionally, GGE have been considered benign, a belief contrary to evidence from neuropsychology studies conducted over the last two decades. In JME, deficits in executive and social functioning are common findings and relate to impaired frontal lobe function. Studies using neuropsychological measures and cognitive imaging paradigms provide evidence for hyperconnectivity between prefrontal and motor cortices, aberrant fronto-thalamo-cortical connectivity, and reduced fronto-cortical and subcortical gray matter volumes, which are associated with altered cognitive performance. Recent research has also identified associations between abnormal hippocampal morphometry and fronto-temporal activation during episodic memory. Longitudinal studies on individuals with newly diagnosed JME have observed cortical dysmaturation, which is paralleled by delayed cognitive development compared to the patients' peers. Comorbidities and cognitive deficits observed in other GGE subtypes, such as visuo-spatial and language deficits in both CAE and JAE, have also been correlated with atypical neurodevelopment. Although it remains unclear whether cognitive impairment profiles differ amongst GGE subtypes, effects may become more pronounced with disease duration, particularly in absence epilepsies. Finally, there is substantial evidence that patients with JME and their unaffected siblings share patterns of cognitive deficits, which is indicative of an underlying genetic etiology (endophenotype), independent of seizures and anti-epileptic medication.
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Affiliation(s)
- Corey Ratcliffe
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, United Kingdom
- MRI Unit, Epilepsy Society, Chalfont St Peter, Buckinghamshire, United Kingdom
| | - Britta Wandschneider
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, United Kingdom
- MRI Unit, Epilepsy Society, Chalfont St Peter, Buckinghamshire, United Kingdom
| | - Sallie Baxendale
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, United Kingdom
- MRI Unit, Epilepsy Society, Chalfont St Peter, Buckinghamshire, United Kingdom
| | - Pamela Thompson
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, United Kingdom
- MRI Unit, Epilepsy Society, Chalfont St Peter, Buckinghamshire, United Kingdom
| | - Matthias J. Koepp
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, United Kingdom
- MRI Unit, Epilepsy Society, Chalfont St Peter, Buckinghamshire, United Kingdom
| | - Lorenzo Caciagli
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, United Kingdom
- MRI Unit, Epilepsy Society, Chalfont St Peter, Buckinghamshire, United Kingdom
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, United States
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24
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Lopes MA, Junges L, Woldman W, Goodfellow M, Terry JR. The Role of Excitability and Network Structure in the Emergence of Focal and Generalized Seizures. Front Neurol 2020; 11:74. [PMID: 32117033 PMCID: PMC7027568 DOI: 10.3389/fneur.2020.00074] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 01/21/2020] [Indexed: 01/12/2023] Open
Abstract
Epileptic seizures are generally classified as either focal or generalized. It had been traditionally assumed that focal seizures imply localized brain abnormalities, whereas generalized seizures involve widespread brain pathologies. However, recent evidence suggests that large-scale brain networks are involved in the generation of focal seizures, and generalized seizures can originate in localized brain regions. Herein we study how network structure and tissue heterogeneities underpin the emergence of focal and widespread seizure dynamics. Mathematical modeling of seizure emergence in brain networks enables the clarification of the characteristics responsible for focal and generalized seizures. We consider neural mass network dynamics of seizure generation in exemplar synthetic networks and we measure the variance in ictogenicity across the network. Ictogenicity is defined as the involvement of network nodes in seizure activity, and its variance is used to quantify whether seizure patterns are focal or widespread across the network. We address both the influence of network structure and different excitability distributions across the network on the ictogenic variance. We find that this variance depends on both network structure and excitability distribution. High variance, i.e., localized seizure activity, is observed in networks highly heterogeneous with regard to the distribution of connections or excitabilities. However, networks that are both heterogeneous in their structure and excitability can underlie the emergence of generalized seizures, depending on the interplay between structure and excitability. Thus, our results imply that the emergence of focal and generalized seizures is underpinned by an interplay between network structure and excitability distribution.
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Affiliation(s)
- Marinho A Lopes
- Living Systems Institute, University of Exeter, Exeter, United Kingdom.,Wellcome Trust Centre for Biomedical Modelling and Analysis, University of Exeter, Exeter, United Kingdom.,EPSRC Centre for Predictive Modelling in Healthcare, University of Exeter, Exeter, United Kingdom.,Department of Engineering Mathematics, University of Bristol, Bristol, United Kingdom.,Cardiff University Brain Research Imaging Centre, School of Psychology, Cardiff University, Cardiff, United Kingdom
| | - Leandro Junges
- Living Systems Institute, University of Exeter, Exeter, United Kingdom.,Wellcome Trust Centre for Biomedical Modelling and Analysis, University of Exeter, Exeter, United Kingdom.,EPSRC Centre for Predictive Modelling in Healthcare, University of Exeter, Exeter, United Kingdom.,Centre for Systems Modelling and Quantitative Biomedicine, University of Birmingham, Birmingham, United Kingdom.,Institute for Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom
| | - Wessel Woldman
- Living Systems Institute, University of Exeter, Exeter, United Kingdom.,Wellcome Trust Centre for Biomedical Modelling and Analysis, University of Exeter, Exeter, United Kingdom.,EPSRC Centre for Predictive Modelling in Healthcare, University of Exeter, Exeter, United Kingdom.,Centre for Systems Modelling and Quantitative Biomedicine, University of Birmingham, Birmingham, United Kingdom.,Institute for Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom
| | - Marc Goodfellow
- Living Systems Institute, University of Exeter, Exeter, United Kingdom.,Wellcome Trust Centre for Biomedical Modelling and Analysis, University of Exeter, Exeter, United Kingdom.,EPSRC Centre for Predictive Modelling in Healthcare, University of Exeter, Exeter, United Kingdom
| | - John R Terry
- Living Systems Institute, University of Exeter, Exeter, United Kingdom.,Wellcome Trust Centre for Biomedical Modelling and Analysis, University of Exeter, Exeter, United Kingdom.,EPSRC Centre for Predictive Modelling in Healthcare, University of Exeter, Exeter, United Kingdom.,Centre for Systems Modelling and Quantitative Biomedicine, University of Birmingham, Birmingham, United Kingdom.,Institute for Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom
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25
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Shi Q, Zhang T, Miao A, Sun J, Sun Y, Chen Q, Hu Z, Xiang J, Wang X. Differences Between Interictal and Ictal Generalized Spike-Wave Discharges in Childhood Absence Epilepsy: A MEG Study. Front Neurol 2020; 10:1359. [PMID: 32038453 PMCID: PMC6992575 DOI: 10.3389/fneur.2019.01359] [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: 07/09/2019] [Accepted: 12/09/2019] [Indexed: 12/05/2022] Open
Abstract
Purpose: To investigate the differences between interictal and ictal generalized spike-wave discharges (GSWDs) for insights on how epileptic activity propagates and the physiopathological mechanisms underlying childhood absence epilepsy (CAE). Methods: Twenty-five patients with CAE were studied using magnetoencephalography (MEG). MEG data were digitized at 6,000 Hz during the interictal and ictal GSWDs. GSWDs were analyzed at both neural magnetic source levels and functional connectivity (FC) in multifrequency bands: delta (1–4 Hz), theta (4–8 Hz), alpha (8–12 Hz), beta (12–30 Hz), gamma (30–80 Hz), ripple (80–250 Hz), and fast ripple (250–500 Hz). Brain FC was studied with the posterior cingulate cortex/precuneus (PCC/pC) as the seed region. Results: The magnetic source of interictal GSWDs mainly locates in the PCC/pC region at 4–8 and 8–12 Hz, while that of ictal GSWDs mainly locates in the medial frontal cortex (MFC) at 80–250 Hz. There were statistically significant differences between interictal and ictal GSWDs (p < 0.05). The FC network involving the PCC/pC showed strong connections in the anterior-posterior pathways (mainly with the frontal cortex) at 80–250 Hz during ictal GSWDs, while the interictal GSWDs FC were mostly limited to the posterior cortex region. There was no significant difference in the magnetic source strength among interictal and ictal GSWDs at all bandwidths. Conclusions: There are significant disparities in the source localization and FC between interictal and ictal GSWDs. Low-frequency activation in the PCC/pC during inhibition of seizures possibly relates to the maintenance of consciousness during interictal GSWDs. High-frequency oscillations (HFOs) of the MFC during CAE may associate with the inducing or occurrence of GSWDs. Weakened network connections may be in favor of preventing overexcitability and relates to the termination of GSWDs.
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Affiliation(s)
- Qi Shi
- Department of Neurology, The Affiliated Brain Hospital of Nanjing Medical University, Nanjing Medical University, Nanjing, China
| | - Tingting Zhang
- Department of Neurology, The Affiliated Brain Hospital of Nanjing Medical University, Nanjing Medical University, Nanjing, China
| | - Ailiang Miao
- Department of Neurology, The Affiliated Brain Hospital of Nanjing Medical University, Nanjing Medical University, Nanjing, China
| | - Jintao Sun
- Department of Neurology, The Affiliated Brain Hospital of Nanjing Medical University, Nanjing Medical University, Nanjing, China
| | - Yulei Sun
- 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
| | - Jing Xiang
- Division of Neurology, MEG Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Xiaoshan Wang
- Department of Neurology, The Affiliated Brain Hospital of Nanjing Medical University, Nanjing Medical University, Nanjing, China
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26
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Cainelli E, Mioni G, Boniver C, Bisiacchi PS, Vecchi M. Time perception in childhood absence epilepsy: Findings from a pilot study. Epilepsy Behav 2019; 99:106460. [PMID: 31470222 DOI: 10.1016/j.yebeh.2019.106460] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 07/28/2019] [Accepted: 07/28/2019] [Indexed: 10/26/2022]
Abstract
OBJECTIVES With this explorative study, we aimed to examine time perception in children with childhood absence epilepsy (CAE) and to compare those children with a matched control group. The study also investigated the association between the neuropsychological performance of the group with CAE and time judgment. We hypothesize that children with CAE could fail in time perception and that this may be because of a common underlying substrate with executive impairments. METHODS Thirteen children with CAE, aged 6-13 years, and 17 healthy children were recruited. All children performed the time bisection task; the children with CAE also performed a cognitive and neuropsychological assessment. We performed a univariate analysis using each parameter of the bisection task (bisection point [BP]) and Weber ratio (WR) as dependent variables, the group (patients vs. controls) as fixed factors and age at evaluation and vocabulary scores as covariates. In the subgroup of patients, we correlated bisection task parameters with neuropsychological tests using a nonparametric partial correlation; the analysis has corrected for age at evaluation. RESULTS The BP and WR measures differed between controls and patients with CAE. In the subgroup of patients also performing a neuropsychological assessment, we found a correlation between the WR measure and performance on the inhibition test (r = -0.641, p = .025), coding test (r = -0.815, p = .014), and Trail Making Test B (TMT B) (r = 0.72, p = .042). CONCLUSIONS We found an altered time perception in a pilot study of a small group of children with CAE. A neurophysiological mechanism underlying CAE seems to influence cognitive and behavioral deficits and time sensibility.
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Affiliation(s)
- Elisa Cainelli
- Department of Development and Socialization, University of Padova, Italy; Child Neurology and Clinical Neurophysiology, Women's and Children's Health Department, Padua University Hospital, Padova, Italy.
| | - Giovanna Mioni
- Department of General Psychology, University of Padova, Italy.
| | - Clementina Boniver
- Child Neurology and Clinical Neurophysiology, Women's and Children's Health Department, Padua University Hospital, Padova, Italy.
| | - Patrizia S Bisiacchi
- Department of General Psychology, University of Padova, Italy; Padova Neuroscience Center, PNC.
| | - Marilena Vecchi
- Child Neurology and Clinical Neurophysiology, Women's and Children's Health Department, Padua University Hospital, Padova, Italy; Neuromotor Rehabilitation Center La Nostra Famiglia Association, Vicenza, Italy.
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27
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Ossenblok P, van Houdt P, Colon A, Stroink H, van Luijtelaar G. A network approach to investigate the bi-hemispheric synchrony in absence epilepsy. Clin Neurophysiol 2019; 130:1611-1619. [PMID: 31319290 DOI: 10.1016/j.clinph.2019.05.034] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 05/11/2019] [Accepted: 05/22/2019] [Indexed: 11/24/2022]
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28
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Kuhlmann L, Lehnertz K, Richardson MP, Schelter B, Zaveri HP. Seizure prediction - ready for a new era. Nat Rev Neurol 2019; 14:618-630. [PMID: 30131521 DOI: 10.1038/s41582-018-0055-2] [Citation(s) in RCA: 191] [Impact Index Per Article: 38.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Epilepsy is a common disorder characterized by recurrent seizures. An overwhelming majority of people with epilepsy regard the unpredictability of seizures as a major issue. More than 30 years of international effort have been devoted to the prediction of seizures, aiming to remove the burden of unpredictability and to couple novel, time-specific treatment to seizure prediction technology. A highly influential review published in 2007 concluded that insufficient evidence indicated that seizures could be predicted. Since then, several advances have been made, including successful prospective seizure prediction using intracranial EEG in a small number of people in a trial of a real-time seizure prediction device. In this Review, we examine advances in the field, including EEG databases, seizure prediction competitions, the prospective trial mentioned and advances in our understanding of the mechanisms of seizures. We argue that these advances, together with statistical evaluations, set the stage for a resurgence in efforts towards the development of seizure prediction methodologies. We propose new avenues of investigation involving a synergy between mechanisms, models, data, devices and algorithms and refine the existing guidelines for the development of seizure prediction technology to instigate development of a solution that removes the burden of the unpredictability of seizures.
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Affiliation(s)
- Levin Kuhlmann
- Centre for Human Psychopharmacology, Swinburne University of Technology, Melbourne, Victoria, Australia.,Department of Medicine - St. Vincent's, The University of Melbourne, Parkville, Victoria, Australia.,Department of Biomedical Engineering, The University of Melbourne, Parkville, Victoria, Australia
| | - Klaus Lehnertz
- Department of Epileptology, University of Bonn, Bonn, Germany. .,Interdisciplinary Center for Complex Systems, University of Bonn, Bonn, Germany.
| | - Mark P Richardson
- Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Björn Schelter
- Institute for Complex Systems and Mathematical Biology, University of Aberdeen, Aberdeen, UK
| | - Hitten P Zaveri
- Department of Neurology, Yale University, New Haven, CT, USA
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29
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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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30
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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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Cortical morphologic changes in recent-onset, drug-naïve idiopathic generalized epilepsy. Magn Reson Imaging 2019; 61:137-142. [PMID: 31129280 DOI: 10.1016/j.mri.2019.05.035] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Revised: 05/20/2019] [Accepted: 05/22/2019] [Indexed: 02/05/2023]
Abstract
PURPOSE Only a few studies have investigated the brain morphology abnormalities in structural MRI in patients with drug-naïve idiopathic generalized epilepsy (IGE) and mainly focused on brain volume changes. In the present study, we aimed to investigate the changes in three morphologic measurement differences including cortical thickness, cortical volume, and surface area using FreeSurfer in a pediatric cohort of recent-onset, drug-naïve IGE. METHODS Forty-five recent-onset, drug-naïve patients diagnosed with IGE and 32 demographically matched healthy controls were recruited. All participants underwent structural MRI scans with a 3.0 T MR system. FreeSurfer, an automated cortical surface reconstruction toolbox, was applied to compare the cortical morphology between patients and controls. The brain regions with significant group differences after multiple comparison correction were extracted in common space for each patient, and then correlated with their clinical characteristics (including onset age, duration of epilepsy, and mini-mental state examination (MMSE)) using partial correlation analysis with age, sex and intracranial volume as covariates. RESULTS Compared with controls, IGE patients showed decreased cortical thickness in the left rostral middle frontal gyrus, decreased cortical volume in the right cuneus and left superior frontal gyrus that extended to the precentral gyrus, and decreased surface area in the right cuneus and right inferior parietal gyrus. None of these regions showed significant relationships with clinical measurements in the patient group. CONCLUSION Our findings suggest that cortical thickness, cortical volume, and surface area changes occurred in the early stage of IGE. These findings provide structural neuroimaging evidence underlying the pathology of IGE.
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Multifocal epilepsy in children is associated with increased long-distance functional connectivity: An explorative EEG-fMRI study. Eur J Paediatr Neurol 2018; 22:1054-1065. [PMID: 30017619 DOI: 10.1016/j.ejpn.2018.07.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Revised: 06/12/2018] [Accepted: 07/01/2018] [Indexed: 01/22/2023]
Abstract
OBJECTIVE Multifocal epileptic activity is an unfavourable feature of a number of epileptic syndromes (Lennox-Gastaut syndrome, West syndrome, severe focal epilepsies) which suggests an overall vulnerability of the brain to pathological synchronization. However, the mechanisms of multifocal activity are insufficiently understood. This explorative study investigates whether pathological connectivity within brain areas of the default mode network as well as thalamus, brainstem and retrosplenial cortex may predispose individuals to multifocal epileptic activity. METHODS 33 children suffering from multifocal and monofocal (control group) epilepsies were investigated using EEG-fMRI recordings during sleep. The blood oxygenated level dependent (BOLD) signal of 15 regions of interest was extracted and temporally correlated (resting-state functional connectivity). RESULTS Patients with monofocal epilepsies were characterized by strong correlations between the corresponding interhemispheric homotopic regions. This pattern of correlations with pronounced short-distance and weak long-distance functional connectivity resembles the connectivity pattern described for healthy children. Patients with multifocal epileptic activity, however, demonstrated significantly stronger correlations between a large number of regions of the default mode network as well as thalamus and brainstem, with a significant increase in long-distance connectivity compared to children with monofocal epileptic activity. In the group of patients with multifocal epilepsies there were no differences in functional connectivity between patients with or without Lennox-Gastaut syndrome. CONCLUSION This explorative study shows that multifocal activity is associated with generally increased long-distance functional connectivity in the brain. It can be suggested that this pronounced connectivity may represent either a risk to pathological over-synchronization or a consequence of the multifocal epileptic activity.
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33
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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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Klamer S, Ethofer T, Torner F, Sahib AK, Elshahabi A, Marquetand J, Martin P, Lerche H, Erb M, Focke NK. Unravelling the brain networks driving spike-wave discharges in genetic generalized epilepsy-common patterns and individual differences. Epilepsia Open 2018; 3:485-494. [PMID: 30525117 PMCID: PMC6276776 DOI: 10.1002/epi4.12252] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/24/2018] [Indexed: 11/08/2022] Open
Abstract
Objective Genetic generalized epilepsies (GGEs) are characterized by generalized spike-wave discharges (GSWDs) in electroencephalography (EEG) recordings without underlying structural brain lesions. The origin of the epileptic activity remains unclear, although several studies have reported involvement of thalamus and default mode network (DMN). The aim of the current study was to investigate the networks involved in the generation and temporal evolution of GSWDs to elucidate the origin and propagation of the underlying generalized epileptic activity. Methods We examined 12 patients with GGE and GSWDs using EEG-functional magnetic resonance imaging (fMRI) and identified involved brain areas on the basis of a classical general linear model (GLM) analysis. The activation time courses of these areas were further investigated to reveal their temporal sequence of activations and deactivations. Dynamic causal modeling (DCM) was used to determine the generator of GSWDs in GGE. Results We observed activity changes in the thalamus, DMN, dorsal attention network (DAN), salience network (SN), basal ganglia, dorsolateral prefrontal cortex, and motor cortex with supplementary motor area, however, with a certain heterogeneity between patients. Investigation of the temporal sequence of activity changes showed deactivations in the DMN and DAN and activations in the SN and thalamus preceding the onset of GSWDs on EEG by several seconds. DCM analysis indicated that the DMN gates GSWDs in GGE. Significance The observed interplay between DMN, DAN, SN, and thalamus may indicate a downregulation of consciousness. The DMN seems to play a leading role as a driving force behind these changes. Overall, however, there were also clear differences in activation patterns between patients, reflecting a certain heterogeneity in this cohort of GGE patients.
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Affiliation(s)
- Silke Klamer
- Department of Neurology and Epileptology Hertie-Institute for Clinical Brain Research University of Tübingen Tübingen Germany
| | - Thomas Ethofer
- Department of Biomedical Magnetic Resonance University of Tübingen Tübingen Germany.,Department of Psychiatry and Psychotherapy University of Tübingen Tübingen Germany.,Werner Reichardt Centre for Integrative Neuroscience Tübingen Germany
| | - Franziska Torner
- Department of Neurology and Epileptology Hertie-Institute for Clinical Brain Research University of Tübingen Tübingen Germany
| | - Ashish Kaul Sahib
- Department of Neurology and Epileptology Hertie-Institute for Clinical Brain Research University of Tübingen Tübingen Germany.,Department of Biomedical Magnetic Resonance University of Tübingen Tübingen Germany.,Werner Reichardt Centre for Integrative Neuroscience Tübingen Germany
| | - Adham Elshahabi
- Department of Neurology and Epileptology Hertie-Institute for Clinical Brain Research University of Tübingen Tübingen Germany.,Werner Reichardt Centre for Integrative Neuroscience Tübingen Germany.,MEG Center University of Tübingen Tübingen Germany
| | - Justus Marquetand
- Department of Neurology and Epileptology Hertie-Institute for Clinical Brain Research University of Tübingen Tübingen Germany
| | - Pascal Martin
- Department of Neurology and Epileptology Hertie-Institute for Clinical Brain Research University of Tübingen Tübingen Germany
| | - Holger Lerche
- Department of Neurology and Epileptology Hertie-Institute for Clinical Brain Research University of Tübingen Tübingen Germany.,Werner Reichardt Centre for Integrative Neuroscience Tübingen Germany
| | - Michael Erb
- Department of Biomedical Magnetic Resonance University of Tübingen Tübingen Germany
| | - Niels K Focke
- Department of Neurology and Epileptology Hertie-Institute for Clinical Brain Research University of Tübingen Tübingen Germany.,Werner Reichardt Centre for Integrative Neuroscience Tübingen Germany
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Youssofzadeh V, Agler W, Tenney JR, Kadis DS. Whole-brain MEG connectivity-based analyses reveals critical hubs in childhood absence epilepsy. Epilepsy Res 2018; 145:102-109. [PMID: 29936300 DOI: 10.1016/j.eplepsyres.2018.06.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2018] [Revised: 03/21/2018] [Accepted: 06/03/2018] [Indexed: 01/01/2023]
Abstract
Absence seizures are thought to be linked to abnormal interplays between regions of a thalamocortical network. However, the complexity of this widespread network makes characterizing the functional interactions among various brain regions challenging. Using whole-brain functional connectivity and network analysis of magnetoencephalography (MEG) data, we explored pre-treatment brain hubs ("highly connected nodes") of patients aged 6 to 12 years with childhood absence epilepsy. We analyzed ictal MEG data of 74 seizures from 16 patients. We employed a time-domain beamformer technique to estimate MEG sources in broadband (1-40 Hz) where the greatest power changes between ictal and preictal periods were identified. A phase synchrony measure, phase locking value, and a graph theory metric, eigenvector centrality (EVC), were utilized to quantify voxel-level connectivity and network hubs of ictal > preictal periods, respectively. A volumetric atlas containing 116 regions of interests (ROIs) was utilized to summarize the network measures. ROIs with EVC (z-score) > 1.96 were reported as critical hubs. ROIs analysis revealed functional-anatomical hubs in a widespread network containing bilateral precuneus (right/left, z = 2.39, 2.18), left thalamus (z = 2.28), and three anterior cerebellar subunits of lobule "IV-V" (z = 3.9), vermis "IV-V" (z = 3.57), and lobule "III" (z = 2.03). Findings suggest that highly connected brain areas or hubs are present in focal cortical, subcortical, and cerebellar regions during absence seizures. Hubs in thalami, precuneus and cingulate cortex generally support a theory of rapidly engaging and bilaterally distributed networks of cortical and subcortical regions responsible for seizures generation, whereas hubs in anterior cerebellar regions may be linked to terminating motor automatisms frequently seen during typical absence seizures. Whole-brain network connectivity is a powerful analytic tool to reveal focal components of absence seizures in MEG. Our investigations can lead to a better understanding of the pathophysiology of CAE.
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Affiliation(s)
- Vahab Youssofzadeh
- Department of Pediatrics, University of Tennessee Health Science Center, Memphis, TN, USA; Neuroscience Institute, Le Bonheur Children's Hospital, Memphis, TN, USA; Pediatric Neuroimaging Research Consortium (PNRC), Cincinnati Children's Hospital Medical Center, Cincinnati OH, USA; Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
| | - William Agler
- Pediatric Neuroimaging Research Consortium (PNRC), Cincinnati Children's Hospital Medical Center, Cincinnati OH, USA; Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
| | - Jeffrey R Tenney
- Pediatric Neuroimaging Research Consortium (PNRC), Cincinnati Children's Hospital Medical Center, Cincinnati OH, USA; Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA; College of Medicine, Department of Pediatrics, University of Cincinnati, Cincinnati OH, USA.
| | - Darren S Kadis
- Pediatric Neuroimaging Research Consortium (PNRC), Cincinnati Children's Hospital Medical Center, Cincinnati OH, USA; Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA; College of Medicine, Department of Pediatrics, University of Cincinnati, Cincinnati OH, USA.
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Tenney JR, Kadis DS, Agler W, Rozhkov L, Altaye M, Xiang J, Vannest J, Glauser TA. Ictal connectivity in childhood absence epilepsy: Associations with outcome. Epilepsia 2018; 59:971-981. [PMID: 29633248 DOI: 10.1111/epi.14067] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/01/2018] [Indexed: 11/30/2022]
Abstract
OBJECTIVE The understanding of childhood absence epilepsy (CAE) has been revolutionized over the past decade, but the biological mechanisms responsible for variable treatment outcomes are unknown. Our purpose in this prospective observational study was to determine how pretreatment ictal network pathways, defined using a combined electroencephalography (EEG)-functional magnetic resonance imaging (EEG-fMRI) and magnetoencephalography (MEG) effective connectivity analysis, were related to treatment response. METHODS Sixteen children with newly diagnosed and drug-naive CAE had 31 typical absence seizures during EEG-fMRI and 74 during MEG. The spatial extent of the pretreatment ictal network was defined using fMRI hemodynamic response with an event-related independent component analysis (eICA). This spatially defined pretreatment ictal network supplied prior information for MEG-effective connectivity analysis calculated using phase slope index (PSI). Treatment outcome was assessed 2 years following diagnosis and dichotomized to ethosuximide (ETX)-treatment responders (N = 11) or nonresponders (N = 5). Effective connectivity of the pretreatment ictal network was compared to the treatment response. RESULTS Patterns of pretreatment connectivity demonstrated strongest connections in the thalamus and posterior brain regions (parietal, posterior cingulate, angular gyrus, precuneus, and occipital) at delta frequencies and the frontal cortices at gamma frequencies (P < .05). ETX treatment nonresponders had pretreatment connectivity, which was decreased in the precuneus region and increased in the frontal cortex compared to ETX responders (P < .05). SIGNIFICANCE Pretreatment ictal connectivity differences in children with CAE were associated with response to antiepileptic treatment. This is a possible mechanism for the variable treatment response seen in patients sharing the same epilepsy syndrome.
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Affiliation(s)
- Jeffrey R Tenney
- Division of Neurology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.,Pediatric Neuroimaging Research Consortium (PNRC), Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Darren S Kadis
- Division of Neurology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.,Pediatric Neuroimaging Research Consortium (PNRC), Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - William Agler
- Division of Neurology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.,Pediatric Neuroimaging Research Consortium (PNRC), Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Leonid Rozhkov
- Division of Neurology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Mekibib Altaye
- Division of Biostatistics and Epidemiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Jing Xiang
- Division of Neurology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.,Pediatric Neuroimaging Research Consortium (PNRC), Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Jennifer Vannest
- Division of Neurology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.,Pediatric Neuroimaging Research Consortium (PNRC), Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Tracy A Glauser
- Division of Neurology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
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The cortical focus in childhood absence epilepsy; evidence from nonlinear analysis of scalp EEG recordings. Clin Neurophysiol 2018; 129:602-617. [DOI: 10.1016/j.clinph.2017.11.029] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 11/05/2017] [Accepted: 11/29/2017] [Indexed: 11/19/2022]
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Gadad V, Sinha S, Mariyappa N, Velmurugan J, Chaitanya G, Saini J, Thennarasu K, Satishchandra P. Source analysis of epileptiform discharges in absence epilepsy using Magnetoencephalography (MEG). Epilepsy Res 2018; 140:46-52. [DOI: 10.1016/j.eplepsyres.2017.12.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 10/27/2017] [Accepted: 12/02/2017] [Indexed: 11/26/2022]
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Unterberger I, Trinka E, Kaplan PW, Walser G, Luef G, Bauer G. Generalized nonmotor (absence) seizures-What do absence, generalized, and nonmotor mean? Epilepsia 2018; 59:523-529. [PMID: 29327337 DOI: 10.1111/epi.13996] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/11/2017] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Clinical absences are now classified as "generalized nonmotor (absence) seizures" by the International League Against Epilepsy (ILAE). The aim of this paper is to critically review the concept of absences and to put the accompanying focal and motor symptoms into the context of the emerging pathophysiological knowledge. METHODS For this narrative review we performed an extensive literature search on the term "absence," and analyzed the plethora of symptoms observed in clinical absences. RESULTS Arising from the localization and the involved cortical networks, motor symptoms may include bilateral mild eyelid fluttering and mild myoclonic jerks of extremities. These motor symptoms may also occur unilaterally, analogous to a focal motor seizure with Jacksonian march. Furthermore, electroencephalography (EEG) abnormalities may exhibit initial frontal focal spikes and consistent asymmetries. Electroclinical characteristics support the cortical focus theory of absence seizures. Simultaneous EEG/functional magnetic resonance imaging (fMRI) measurements document cortical deactivation and thalamic activation. Cortical deactivation is related to slow waves and disturbances of consciousness of varying degrees. Motor symptoms correspond to the spike component of the 3/s spike-and-wave-discharges. Thalamic activation can be interpreted as a response to overcome cortical deactivation. Furthermore, arousal reaction during drowsiness or sleep triggers spikes in an abnormally excitable cortex. An initial disturbance in arousal mechanisms ("dyshormia") might be responsible for the start of this abnormal sequence. SIGNIFICANCE The classification as "generalized nonfocal and nonmotor (absence) seizure" does not covey the complex semiology of a patient's clinical events.
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Affiliation(s)
- Iris Unterberger
- Department of Neurology, Innsbruck Medical University, Innsbruck, Austria
| | - Eugen Trinka
- Department of Neurology, Christian-Doppler-Klinik, Paracelsus Medical University of Salzburg, Salzburg, Austria
| | | | - Gerald Walser
- Department of Neurology, Innsbruck Medical University, Innsbruck, Austria
| | - Gerhard Luef
- Department of Neurology, Innsbruck Medical University, Innsbruck, Austria
| | - Gerhard Bauer
- Department of Neurology, Innsbruck Medical University, Innsbruck, Austria
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Qiu W, Yu C, Gao Y, Miao A, Tang L, Huang S, Jiang W, Sun J, Xiang J, Wang X. Disrupted topological organization of structural brain networks in childhood absence epilepsy. Sci Rep 2017; 7:11973. [PMID: 28931825 PMCID: PMC5607318 DOI: 10.1038/s41598-017-10778-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 08/14/2017] [Indexed: 11/26/2022] Open
Abstract
Childhood absence epilepsy (CAE) is the most common paediatric epilepsy syndrome and is characterized by frequent and transient impairment of consciousness. In this study, we explored structural brain network alterations in CAE and their association with clinical characteristics. A whole-brain structural network was constructed for each participant based on diffusion-weighted MRI and probabilistic tractography. The topological metrics were then evaluated. For the first time, we uncovered modular topology in CAE patients that was similar to healthy controls. However, the strength, efficiency and small-world properties of the structural network in CAE were seriously damaged. At the whole brain level, decreased strength, global efficiency, local efficiency, clustering coefficient, normalized clustering coefficient and small-worldness values of the network were detected in CAE, while the values of characteristic path length and normalized characteristic path length were abnormally increased. At the regional level, especially the prominent regions of the bilateral precuneus showed reduced nodal efficiency, and the reduction of efficiency was significantly correlated with disease duration. The current results demonstrate significant alterations of structural networks in CAE patients, and the impairments tend to grow worse over time. Our findings may provide a new way to understand the pathophysiological mechanism of CAE.
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Affiliation(s)
- Wenchao Qiu
- Department of Neurology, The Affiliated Huaian Hospital of Xuzhou Medical University, Huaian, China
| | - Chuanyong Yu
- Department of Neurology, Affiliated Nanjing Brain Hospital, Nanjing Medical University, Nanjing, China
| | - Yuan Gao
- Department of Neurology, Affiliated Nanjing Brain Hospital, Nanjing Medical University, Nanjing, China
| | - Ailiang Miao
- Department of Neurology, Affiliated Nanjing Brain Hospital, Nanjing Medical University, Nanjing, China
| | - Lu Tang
- Department of Neurology, Affiliated Nanjing Brain Hospital, Nanjing Medical University, Nanjing, China
| | - Shuyang Huang
- Department of Neurology, Affiliated Nanjing Brain Hospital, Nanjing Medical University, Nanjing, China
| | - Wenwen Jiang
- Department of Neurology, Affiliated Nanjing Brain Hospital, Nanjing Medical University, Nanjing, China
| | - Jintao Sun
- Department of Neurology, Affiliated Nanjing Brain Hospital, Nanjing Medical University, Nanjing, China
| | - Jing Xiang
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Center, USA
| | - Xiaoshan Wang
- Department of Neurology, Affiliated Nanjing Brain Hospital, Nanjing Medical University, Nanjing, China.
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Tsoures E, Lewerenz J, Pinkhardt E, Ludolph AC, Fauser S. Electroencephalographic findings in patients with circumscribed thalamic lesions. Epilepsy Res 2017; 135:115-122. [DOI: 10.1016/j.eplepsyres.2017.06.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 04/20/2017] [Accepted: 06/13/2017] [Indexed: 10/19/2022]
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Abstract
In recent years, the field of neuroimaging has undergone dramatic development. Specifically, of importance for clinicians and researchers managing patients with epilepsies, new methods of brain imaging in search of the seizure-producing abnormalities have been implemented, and older methods have undergone additional refinement. Methodology to predict seizure freedom and cognitive outcome has also rapidly progressed. In general, the image data processing methods are very different and more complicated than even a decade ago. In this review, we identify the recent developments in neuroimaging that are aimed at improved management of epilepsy patients. Advances in structural imaging, diffusion imaging, fMRI, structural and functional connectivity, hybrid imaging methods, quantitative neuroimaging, and machine-learning are discussed. We also briefly summarize the potential new developments that may shape the field of neuroimaging in the near future and may advance not only our understanding of epileptic networks as the source of treatment-resistant seizures but also better define the areas that need to be treated in order to provide the patients with better long-term outcomes.
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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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Altered degree centrality in childhood absence epilepsy: A resting-state fMRI study. J Neurol Sci 2016; 373:274-279. [PMID: 28131205 DOI: 10.1016/j.jns.2016.12.054] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Revised: 12/14/2016] [Accepted: 12/26/2016] [Indexed: 12/13/2022]
Abstract
Modern network studies have suggested that the pathology of many neurological diseases is in fact not equally distributed over the brain but preferentially affects the hub regions. This study aims to investigate how hub regions were affected in Children with Childhood absence epilepsy (CAE) using resting-state fMRI (rs-fMRI). As one important measures obtained from rs-fMRI, degree centrality (DC) calculates the number of direct connections between a given node and the rest of the brain within the entire connectivity matrix of the brain. In this study, twenty-five CAE children and 25 healthy controls were recruited to investigate the DC changes in CAE patients. Compared with healthy controls, children with CAE showed significantly decreased DC in default mode network (DMN, medial prefrontal cortex, posterior cingulate cortex, precuneus and middle temporal cortex) and increased DC in thalamus. Importantly, significant negative correlation between the epilepsy duration and DC was found in precuneus. Our results suggested selective and specific disruption of hub nodes, especially thalamus and the highly connected brain regions within DMN, might underlie the pathophysiological mechanism of CAE.
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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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Russo E, Citraro R, Constanti A, Leo A, Lüttjohann A, van Luijtelaar G, De Sarro G. Upholding WAG/Rij rats as a model of absence epileptogenesis: Hidden mechanisms and a new theory on seizure development. Neurosci Biobehav Rev 2016; 71:388-408. [DOI: 10.1016/j.neubiorev.2016.09.017] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2015] [Revised: 09/19/2016] [Indexed: 02/06/2023]
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Dong L, Wang P, Peng R, Jiang S, Klugah-Brown B, Luo C, Yao D. Altered basal ganglia-cortical functional connections in frontal lobe epilepsy: A resting-state fMRI study. Epilepsy Res 2016; 128:12-20. [PMID: 27792884 DOI: 10.1016/j.eplepsyres.2016.10.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Revised: 10/05/2016] [Accepted: 10/24/2016] [Indexed: 10/20/2022]
Abstract
OBJECTIVES The purpose of this study was to investigate alterations of basal ganglia-cortical functional connections in patients with frontal lobe epilepsy (FLE). METHOD Resting-state functional magnetic resonance imaging (fMRI) data were gathered from 19 FLE patients and 19 age- and gender-matched healthy controls. Functional connectivity (FC) analysis was used to assess the functional connections between basal ganglia and cerebral cortex. Regions of interest, including the left/right caudate, putamen, pallidum and thalamus, were selected as the seeds. Two sample t-test was used to determine the difference between patients and controls, while controlling the age, gender and head motions. RESULTS Compared with controls, FLE patients demonstrated increased FCs between basal ganglia and regions including the right fusiform gyrus, the bilateral cingulate gyrus, the precuneus and anterior cingulate gyrus. Reduced FCs were mainly located in a range of brain regions including the bilateral middle occipital gyrus, the ventral frontal lobe, the right putamen, the left fusiform gyrus and right rolandic operculum. In addition, the relationships between basal ganglia-cingulate connections and durations of epilepsy were also found. CONCLUSION The alterations of functional integrity within the basal ganglia, as well as its connections to limbic and ventral frontal areas, indicate the important roles of the basal ganglia-cortical functional connections in FLE, and provide new insights in the pathophysiological mechanism of FLE.
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Affiliation(s)
- Li Dong
- Key Laboratory for NeuroInformation of Ministry of Education, Center for Information in Medicine, High-Field Magnetic Resonance Brain Imaging Key Laboratory of Sichuan Province, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China
| | - Pu Wang
- Key Laboratory for NeuroInformation of Ministry of Education, Center for Information in Medicine, High-Field Magnetic Resonance Brain Imaging Key Laboratory of Sichuan Province, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China
| | - Rui Peng
- Key Laboratory for NeuroInformation of Ministry of Education, Center for Information in Medicine, High-Field Magnetic Resonance Brain Imaging Key Laboratory of Sichuan Province, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China
| | - Sisi Jiang
- Key Laboratory for NeuroInformation of Ministry of Education, Center for Information in Medicine, High-Field Magnetic Resonance Brain Imaging Key Laboratory of Sichuan Province, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China
| | - Benjamin Klugah-Brown
- Key Laboratory for NeuroInformation of Ministry of Education, Center for Information in Medicine, High-Field Magnetic Resonance Brain Imaging Key Laboratory of Sichuan Province, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China
| | - Cheng Luo
- Key Laboratory for NeuroInformation of Ministry of Education, Center for Information in Medicine, High-Field Magnetic Resonance Brain Imaging Key Laboratory of Sichuan Province, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China.
| | - Dezhong Yao
- Key Laboratory for NeuroInformation of Ministry of Education, Center for Information in Medicine, High-Field Magnetic Resonance Brain Imaging Key Laboratory of Sichuan Province, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China
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Arakaki T, Mahon S, Charpier S, Leblois A, Hansel D. The Role of Striatal Feedforward Inhibition in the Maintenance of Absence Seizures. J Neurosci 2016; 36:9618-32. [PMID: 27629713 PMCID: PMC6601939 DOI: 10.1523/jneurosci.0208-16.2016] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 07/24/2016] [Accepted: 07/25/2016] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Absence seizures are characterized by brief interruptions of conscious experience accompanied by oscillations of activity synchronized across many brain areas. Although the dynamics of the thalamocortical circuits are traditionally thought to underlie absence seizures, converging experimental evidence supports the key involvement of the basal ganglia (BG). In this theoretical work, we argue that the BG are essential for the maintenance of absence seizures. To this end, we combine analytical calculations with numerical simulations to investigate a computational model of the BG-thalamo-cortical network. We demonstrate that abnormally strong striatal feedforward inhibition can promote synchronous oscillatory activity that persists in the network over several tens of seconds as observed during seizures. We show that these maintained oscillations result from an interplay between the negative feedback through the cortico-subthalamo-nigral pathway and the striatal feedforward inhibition. The negative feedback promotes epileptic oscillations whereas the striatal feedforward inhibition suppresses the positive feedback provided by the cortico-striato-nigral pathway. Our theory is consistent with experimental evidence regarding the influence of BG on seizures (e.g., with the fact that a pharmacological blockade of the subthalamo-nigral pathway suppresses seizures). It also accounts for the observed strong suppression of the striatal output during seizures. Our theory predicts that well-timed transient excitatory inputs to the cortex advance the termination of absence seizures. In contrast with the thalamocortical theory, it also predicts that reducing the synaptic transmission along the cortico-subthalamo-nigral pathway while keeping constant the average firing rate of substantia nigra pars reticulata reduces the incidence of seizures. SIGNIFICANCE STATEMENT Absence seizures are characterized by brief interruptions of consciousness accompanied by abnormal brain oscillations persisting tens of seconds. Thalamocortical circuits are traditionally thought to underlie absence seizures. However, recent experiments have highlighted the key role of the basal ganglia (BG). This work argues for a novel theory according to which the BG drive the oscillatory patterns of activity occurring during the seizures. It demonstrates that abnormally strong striatal feedforward inhibition promotes synchronous oscillatory activity in the BG-thalamo-cortical network and relate this property to the observed strong suppression of the striatal output during seizures. The theory is compatible with virtually all known experimental results, and it predicts that well-timed transient excitatory inputs to the cortex advance the termination of absence seizures.
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Affiliation(s)
- Takafumi Arakaki
- Center of Neurophysics, Physiology and Pathology, UMR 8119 CNRS, Paris Descartes University, 75270 Paris, France
| | - Séverine Mahon
- Sorbonne Universités, Université Paris 06, UPMC, INSERM U 1127, CNRS UMR 7225, Institut du Cerveau et de la Moelle épinière, ICM, Hôpital Pitié-Salpêtrière, F-75013 Paris, France, and
| | - Stéphane Charpier
- Sorbonne Universités, Université Paris 06, UPMC, INSERM U 1127, CNRS UMR 7225, Institut du Cerveau et de la Moelle épinière, ICM, Hôpital Pitié-Salpêtrière, F-75013 Paris, France, and UPMC Université Paris 06, F-75005 Paris, France
| | - Arthur Leblois
- Center of Neurophysics, Physiology and Pathology, UMR 8119 CNRS, Paris Descartes University, 75270 Paris, France
| | - David Hansel
- Center of Neurophysics, Physiology and Pathology, UMR 8119 CNRS, Paris Descartes University, 75270 Paris, France,
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Szaflarski JP, Lee S, Allendorfer JB, Gaston TE, Knowlton RC, Pati S, Ver Hoef LW, Deutsch G. White Matter Abnormalities in Patients with Treatment-Resistant Genetic Generalized Epilepsies. Med Sci Monit 2016; 22:1966-75. [PMID: 27283395 PMCID: PMC4917325 DOI: 10.12659/msm.897002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Background Genetic generalized epilepsies (GGEs) are associated with microstructural brain abnormalities that can be evaluated with diffusion tensor imaging (DTI). Available studies on GGEs have conflicting results. Our primary goal was to compare the white matter structure in a cohort of patients with video/EEG-confirmed GGEs to healthy controls (HCs). Our secondary goal was to assess the potential effect of age at GGE onset on the white matter structure. Material/Methods A convenience sample of 23 patients with well-characterized treatment-resistant GGEs (13 female) was compared to 23 HCs. All participants received MRI at 3T. DTI indices, including fractional anisotropy (FA) and mean diffusivity (MD), were compared between groups using Tract-Based Spatial Statistics (TBSS). Results After controlling for differences between groups, abnormalities in DTI parameters were observed in patients with GGEs, including decreases in functional anisotropy (FA) in the hemispheric (left>right) and brain stem white matter. The examination of the effect of age at GGE onset on the white matter integrity revealed a significant negative correlation in the left parietal white matter region FA (R=−0.504; p=0.017); similar trends were observed in the white matter underlying left motor cortex (R=−0.357; p=0.103) and left posterior limb of the internal capsule (R=−0.319; p=0.148). Conclusions Our study confirms the presence of widespread white matter abnormalities in patients with GGEs and provides evidence that the age at GGE onset may have an important effect on white matter integrity.
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Affiliation(s)
- Jerzy P Szaflarski
- Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Seongtaek Lee
- Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Jane B Allendorfer
- Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Tyler E Gaston
- Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Robert C Knowlton
- Department of Neurology, University of California at San Francisco, San Francisco, CA, USA
| | - Sandipan Pati
- Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Lawrence W Ver Hoef
- Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Georg Deutsch
- Department of Radiology, University of Alabama at Birmingham, Birmingham, AL, USA
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Nonoda Y, Miyakoshi M, Ojeda A, Makeig S, Juhász C, Sood S, Asano E. Interictal high-frequency oscillations generated by seizure onset and eloquent areas may be differentially coupled with different slow waves. Clin Neurophysiol 2016; 127:2489-99. [PMID: 27178869 DOI: 10.1016/j.clinph.2016.03.022] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 03/17/2016] [Accepted: 03/22/2016] [Indexed: 11/19/2022]
Abstract
OBJECTIVE High-frequency oscillations (HFOs) can be spontaneously generated by seizure-onset and functionally-important areas. We determined if consideration of the spectral frequency bands of coupled slow-waves could distinguish between epileptogenic and physiological HFOs. METHODS We studied a consecutive series of 13 children with focal epilepsy who underwent extraoperative electrocorticography. We measured the occurrence rate of HFOs during slow-wave sleep at each electrode site. We subsequently determined the performance of HFO rate for localization of seizure-onset sites and undesirable detection of nonepileptic sensorimotor-visual sites defined by neurostimulation. We likewise determined the predictive performance of modulation index: MI(XHz)&(YHz), reflecting the strength of coupling between amplitude of HFOsXHz and phase of slow-waveYHz. The predictive accuracy was quantified using the area under the curve (AUC) on receiver-operating characteristics analysis. RESULTS Increase in HFO rate localized seizure-onset sites (AUC⩾0.72; p<0.001), but also undesirably detected nonepileptic sensorimotor-visual sites (AUC⩾0.58; p<0.001). Increase in MI(HFOs)&(3-4Hz) also detected both seizure-onset (AUC⩾0.74; p<0.001) and nonepileptic sensorimotor-visual sites (AUC⩾0.59; p<0.001). Increase in subtraction-MIHFOs [defined as subtraction of MI(HFOs)&(0.5-1Hz) from MI(HFOs)&(3-4Hz)] localized seizure-onset sites (AUC⩾0.71; p<0.001), but rather avoided detection of nonepileptic sensorimotor-visual sites (AUC⩽0.42; p<0.001). CONCLUSION Our data suggest that epileptogenic HFOs may be coupled with slow-wave3-4Hz more preferentially than slow-wave0.5-1Hz, whereas physiologic HFOs with slow-wave0.5-1Hz more preferentially than slow-wave3-4Hz during slow-wave sleep. SIGNIFICANCE Further studies in larger samples are warranted to determine if consideration of the spectral frequency bands of slow-waves coupled with HFOs can positively contribute to presurgical evaluation of patients with focal epilepsy.
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Affiliation(s)
- Yutaka Nonoda
- Pediatrics, Wayne State University, Children's Hospital of Michigan, Detroit, MI, USA
| | - Makoto Miyakoshi
- Swartz Center for Computational Neuroscience, Institute for Neural Computation, University of California San Diego, La Jolla, CA, USA
| | - Alejandro Ojeda
- Swartz Center for Computational Neuroscience, Institute for Neural Computation, University of California San Diego, La Jolla, CA, USA
| | - Scott Makeig
- Swartz Center for Computational Neuroscience, Institute for Neural Computation, University of California San Diego, La Jolla, CA, USA
| | - Csaba Juhász
- Pediatrics, Wayne State University, Children's Hospital of Michigan, Detroit, MI, USA; Neurology, Wayne State University, Children's Hospital of Michigan, Detroit, MI, USA
| | - Sandeep Sood
- Neurosurgery, Wayne State University, Children's Hospital of Michigan, Detroit, MI, USA
| | - Eishi Asano
- Pediatrics, Wayne State University, Children's Hospital of Michigan, Detroit, MI, USA; Neurology, Wayne State University, Children's Hospital of Michigan, Detroit, MI, USA.
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