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Christian Vollmar - One of the best experts on this subject based on the ideXlab platform.
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abnormal hippocampal structure and function in Juvenile Myoclonic Epilepsy and unaffected siblings
Brain, 2019Co-Authors: Christian Vollmar, Britta Wandschneider, Lorenzo Caciagli, Fenglai XiaoAbstract:Juvenile Myoclonic Epilepsy is the most common genetic generalized Epilepsy syndrome, characterized by a complex polygenetic aetiology. Structural and functional MRI studies demonstrated mesial or lateral frontal cortical derangements and impaired fronto-cortico-subcortical connectivity in patients and their unaffected siblings. The presence of hippocampal abnormalities and associated memory deficits is controversial, and functional MRI studies in Juvenile Myoclonic Epilepsy have not tested hippocampal activation. In this observational study, we implemented multi-modal MRI and neuropsychological data to investigate hippocampal structure and function in 37 patients with Juvenile Myoclonic Epilepsy, 16 unaffected siblings and 20 healthy controls, comparable for age, gender, handedness and hemispheric dominance as assessed with language laterality indices. Automated hippocampal volumetry was complemented by validated qualitative and quantitative morphological criteria to detect hippocampal malrotation, assumed to represent a neurodevelopmental marker. Neuropsychological measures of verbal and visuo-spatial learning and an event-related verbal and visual memory functional MRI paradigm addressed mesiotemporal function. We detected a reduction of mean left hippocampal volume in patients and their siblings compared with controls (P < 0.01). Unilateral or bilateral hippocampal malrotation was identified in 51% of patients and 50% of siblings, against 15% of controls (P < 0.05). For bilateral hippocampi, quantitative markers of verticalization had significantly larger values in patients and siblings compared with controls (P < 0.05). In the patient subgroup, there was no relationship between structural measures and age at disease onset or degree of seizure control. No overt impairment of verbal and visual memory was identified with neuropsychological tests. Functional mapping highlighted atypical patterns of hippocampal activation, pointing to abnormal recruitment during verbal encoding in patients and their siblings [P < 0.05, familywise error (FWE)-corrected]. Subgroup analyses indicated distinct profiles of hypoactivation along the hippocampal long axis in Juvenile Myoclonic Epilepsy patients with and without malrotation; patients with malrotation also exhibited reduced frontal recruitment for verbal memory, and more pronounced left posterior hippocampal involvement for visual memory. Linear models across the entire study cohort indicated significant associations between morphological markers of hippocampal positioning and hippocampal activation for verbal items (all P < 0.05, FWE-corrected). We demonstrate abnormalities of hippocampal volume, shape and positioning in patients with Juvenile Myoclonic Epilepsy and their siblings, which are associated with reorganization of function and imply an underlying neurodevelopmental mechanism with expression during the prenatal stage. Co-segregation of abnormal hippocampal morphology in patients and their siblings is suggestive of a genetic imaging phenotype, independent of disease activity, and can be construed as a novel endophenotype of Juvenile Myoclonic Epilepsy.
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motor co activation in siblings of patients with Juvenile Myoclonic Epilepsy an imaging endophenotype
Brain, 2014Co-Authors: Britta Wandschneider, Christian Vollmar, Mark R Symms, John S Duncan, Maria Centeno, Pamela J Thompson, Matthias J KoeppAbstract:Juvenile Myoclonic Epilepsy is a heritable idiopathic generalized Epilepsy syndrome, characterized by Myoclonic jerks and frequently triggered by cognitive effort. Impairment of frontal lobe cognitive functions has been reported in patients with Juvenile Myoclonic Epilepsy and their unaffected siblings. In a recent functional magnetic resonance imaging study we reported abnormal co-activation of the motor cortex and increased functional connectivity between the motor system and prefrontal cognitive networks during a working memory paradigm, providing an underlying mechanism for cognitively triggered jerks. In this study, we used the same task in 15 unaffected siblings (10 female; age range 18-65 years, median 40) of 11 of those patients with Juvenile Myoclonic Epilepsy (six female; age range 22-54 years, median 35) and compared functional magnetic resonance imaging activations with 20 age- and gender-matched healthy control subjects (12 female; age range 23-46 years, median 30.5). Unaffected siblings showed abnormal primary motor cortex and supplementary motor area co-activation with increasing cognitive load, as well as increased task-related functional connectivity between motor and prefrontal cognitive networks, with a similar pattern to patients (P < 0.001 uncorrected; 20-voxel threshold extent). This finding in unaffected siblings suggests that altered motor system activation and functional connectivity is not medication- or seizure-related, but represents a potential underlying mechanism for impairment of frontal lobe functions in both patients and siblings, and so constitutes an endophenotype of Juvenile Myoclonic Epilepsy.
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risk taking behavior in Juvenile Myoclonic Epilepsy
Epilepsia, 2013Co-Authors: Christian Vollmar, Britta Wandschneider, Maria Centeno, J Stretton, Jonathan OmuircheartaighAbstract:Objective Patients with Juvenile Myoclonic Epilepsy (JME) often present with risk-taking behavior, suggestive of frontal lobe dysfunction. Recent studies confirm functional and microstructural changes within the frontal lobes in JME. This study aimed at characterizing decision-making behavior in JME and its neuronal correlates using functional magnetic resonance imaging (fMRI).
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Risk‐taking behavior in Juvenile Myoclonic Epilepsy
Epilepsia, 2013Co-Authors: Britta Wandschneider, Christian Vollmar, Jonathan O'muircheartaigh, Gareth J Barker, Mark R Symms, Veena Kumari, Maria Centeno, J Stretton, Pamela J Thompson, John S DuncanAbstract:Objective Patients with Juvenile Myoclonic Epilepsy (JME) often present with risk-taking behavior, suggestive of frontal lobe dysfunction. Recent studies confirm functional and microstructural changes within the frontal lobes in JME. This study aimed at characterizing decision-making behavior in JME and its neuronal correlates using functional magnetic resonance imaging (fMRI).
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abnormal thalamocortical structural and functional connectivity in Juvenile Myoclonic Epilepsy
Brain, 2012Co-Authors: Christian Vollmar, Gareth J Barker, Mark R Symms, Veena Kumari, Jonathan Omuircheartaigh, Pamela J ThompsonAbstract:Juvenile Myoclonic Epilepsy is the most common idiopathic generalized Epilepsy, characterized by frequent Myoclonic jerks, generalized tonic-clonic seizures and, less commonly, absences. Neuropsychological and, less consistently, anatomical studies have indicated frontal lobe dysfunction in the disease. Given its presumed thalamo–cortical basis, we investigated thalamo–cortical structural connectivity, as measured by diffusion tensor imaging, in a cohort of 28 participants with Juvenile Myoclonic Epilepsy and detected changes in an anterior thalamo–cortical bundle compared with healthy control subjects. We then investigated task-modulated functional connectivity from the anterior thalamic region identified using functional magnetic resonance imaging in a task consistently shown to be impaired in this group, phonemic verbal fluency. We demonstrate an alteration in task-modulated connectivity in a region of frontal cortex directly connected to the thalamus via the same anatomical bundle, and overlapping with the supplementary motor area. Further, we show that the degree of abnormal connectivity is related to disease severity in those with active seizures. By integrating methods examining structural and effective interregional connectivity, these results provide convincing evidence for abnormalities in a specific thalamo–cortical circuit, with reduced structural and task-induced functional connectivity, which may underlie the functional abnormalities in this idiopathic Epilepsy.
Britta Wandschneider - One of the best experts on this subject based on the ideXlab platform.
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abnormal hippocampal structure and function in Juvenile Myoclonic Epilepsy and unaffected siblings
Brain, 2019Co-Authors: Christian Vollmar, Britta Wandschneider, Lorenzo Caciagli, Fenglai XiaoAbstract:Juvenile Myoclonic Epilepsy is the most common genetic generalized Epilepsy syndrome, characterized by a complex polygenetic aetiology. Structural and functional MRI studies demonstrated mesial or lateral frontal cortical derangements and impaired fronto-cortico-subcortical connectivity in patients and their unaffected siblings. The presence of hippocampal abnormalities and associated memory deficits is controversial, and functional MRI studies in Juvenile Myoclonic Epilepsy have not tested hippocampal activation. In this observational study, we implemented multi-modal MRI and neuropsychological data to investigate hippocampal structure and function in 37 patients with Juvenile Myoclonic Epilepsy, 16 unaffected siblings and 20 healthy controls, comparable for age, gender, handedness and hemispheric dominance as assessed with language laterality indices. Automated hippocampal volumetry was complemented by validated qualitative and quantitative morphological criteria to detect hippocampal malrotation, assumed to represent a neurodevelopmental marker. Neuropsychological measures of verbal and visuo-spatial learning and an event-related verbal and visual memory functional MRI paradigm addressed mesiotemporal function. We detected a reduction of mean left hippocampal volume in patients and their siblings compared with controls (P < 0.01). Unilateral or bilateral hippocampal malrotation was identified in 51% of patients and 50% of siblings, against 15% of controls (P < 0.05). For bilateral hippocampi, quantitative markers of verticalization had significantly larger values in patients and siblings compared with controls (P < 0.05). In the patient subgroup, there was no relationship between structural measures and age at disease onset or degree of seizure control. No overt impairment of verbal and visual memory was identified with neuropsychological tests. Functional mapping highlighted atypical patterns of hippocampal activation, pointing to abnormal recruitment during verbal encoding in patients and their siblings [P < 0.05, familywise error (FWE)-corrected]. Subgroup analyses indicated distinct profiles of hypoactivation along the hippocampal long axis in Juvenile Myoclonic Epilepsy patients with and without malrotation; patients with malrotation also exhibited reduced frontal recruitment for verbal memory, and more pronounced left posterior hippocampal involvement for visual memory. Linear models across the entire study cohort indicated significant associations between morphological markers of hippocampal positioning and hippocampal activation for verbal items (all P < 0.05, FWE-corrected). We demonstrate abnormalities of hippocampal volume, shape and positioning in patients with Juvenile Myoclonic Epilepsy and their siblings, which are associated with reorganization of function and imply an underlying neurodevelopmental mechanism with expression during the prenatal stage. Co-segregation of abnormal hippocampal morphology in patients and their siblings is suggestive of a genetic imaging phenotype, independent of disease activity, and can be construed as a novel endophenotype of Juvenile Myoclonic Epilepsy.
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motor co activation in siblings of patients with Juvenile Myoclonic Epilepsy an imaging endophenotype
Brain, 2014Co-Authors: Britta Wandschneider, Christian Vollmar, Mark R Symms, John S Duncan, Maria Centeno, Pamela J Thompson, Matthias J KoeppAbstract:Juvenile Myoclonic Epilepsy is a heritable idiopathic generalized Epilepsy syndrome, characterized by Myoclonic jerks and frequently triggered by cognitive effort. Impairment of frontal lobe cognitive functions has been reported in patients with Juvenile Myoclonic Epilepsy and their unaffected siblings. In a recent functional magnetic resonance imaging study we reported abnormal co-activation of the motor cortex and increased functional connectivity between the motor system and prefrontal cognitive networks during a working memory paradigm, providing an underlying mechanism for cognitively triggered jerks. In this study, we used the same task in 15 unaffected siblings (10 female; age range 18-65 years, median 40) of 11 of those patients with Juvenile Myoclonic Epilepsy (six female; age range 22-54 years, median 35) and compared functional magnetic resonance imaging activations with 20 age- and gender-matched healthy control subjects (12 female; age range 23-46 years, median 30.5). Unaffected siblings showed abnormal primary motor cortex and supplementary motor area co-activation with increasing cognitive load, as well as increased task-related functional connectivity between motor and prefrontal cognitive networks, with a similar pattern to patients (P < 0.001 uncorrected; 20-voxel threshold extent). This finding in unaffected siblings suggests that altered motor system activation and functional connectivity is not medication- or seizure-related, but represents a potential underlying mechanism for impairment of frontal lobe functions in both patients and siblings, and so constitutes an endophenotype of Juvenile Myoclonic Epilepsy.
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risk taking behavior in Juvenile Myoclonic Epilepsy
Epilepsia, 2013Co-Authors: Christian Vollmar, Britta Wandschneider, Maria Centeno, J Stretton, Jonathan OmuircheartaighAbstract:Objective Patients with Juvenile Myoclonic Epilepsy (JME) often present with risk-taking behavior, suggestive of frontal lobe dysfunction. Recent studies confirm functional and microstructural changes within the frontal lobes in JME. This study aimed at characterizing decision-making behavior in JME and its neuronal correlates using functional magnetic resonance imaging (fMRI).
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Risk‐taking behavior in Juvenile Myoclonic Epilepsy
Epilepsia, 2013Co-Authors: Britta Wandschneider, Christian Vollmar, Jonathan O'muircheartaigh, Gareth J Barker, Mark R Symms, Veena Kumari, Maria Centeno, J Stretton, Pamela J Thompson, John S DuncanAbstract:Objective Patients with Juvenile Myoclonic Epilepsy (JME) often present with risk-taking behavior, suggestive of frontal lobe dysfunction. Recent studies confirm functional and microstructural changes within the frontal lobes in JME. This study aimed at characterizing decision-making behavior in JME and its neuronal correlates using functional magnetic resonance imaging (fMRI).
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Juvenile Myoclonic Epilepsy neuroimaging findings
Epilepsy & Behavior, 2013Co-Authors: Matthias J Koepp, Friedrich G Woermann, Ivanka Savic, Britta WandschneiderAbstract:Abstract Juvenile Myoclonic Epilepsy (JME) has been classified as a syndrome of idiopathic generalized Epilepsy and is characterized by specific types of seizures, showing a lack of pathology using magnetic resonance imaging (MRI) and computed tomography scanning. However, JME is associated with a particular personality profile, and behavioral and neuropsychological studies have suggested the possible involvement of frontal lobe dysfunction. The development of highly sensitive neuroimaging techniques has provided a means of elucidating the underlying mechanisms of JME. Positron emission tomography demonstrated metabolic and neurotransmitter changes in the dorsolateral prefrontal cortex reflecting the particular cognitive and behavioral profile of JME patients. 1H-magnetic resonance spectroscopy has shown evidence of thalamic dysfunction, which appears to be progressive. Such techniques provide evidence of multi-focal disease mechanisms, suggesting that JME is a frontal lobe variant of a multi-regional, thalamocortical ‘network’ Epilepsy, rather than a generalized Epilepsy syndrome. Quantitative MRI revealed significant abnormalities of cortical gray matter in medial frontal areas close to the supplementary motor area and diffusion abnormalities with increased functional coupling between the motor and prefrontal cognitive systems. This altered structural connectivity of the supplementary motor area provides an explanatory framework for the particular imaging findings, seizure type, and seizure‐provoking mechanisms in JME. This article is part of a supplemental special issue entitled Juvenile Myoclonic Epilepsy: What is it Really?
Jonathan Omuircheartaigh - One of the best experts on this subject based on the ideXlab platform.
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risk taking behavior in Juvenile Myoclonic Epilepsy
Epilepsia, 2013Co-Authors: Christian Vollmar, Britta Wandschneider, Maria Centeno, J Stretton, Jonathan OmuircheartaighAbstract:Objective Patients with Juvenile Myoclonic Epilepsy (JME) often present with risk-taking behavior, suggestive of frontal lobe dysfunction. Recent studies confirm functional and microstructural changes within the frontal lobes in JME. This study aimed at characterizing decision-making behavior in JME and its neuronal correlates using functional magnetic resonance imaging (fMRI).
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abnormal thalamocortical structural and functional connectivity in Juvenile Myoclonic Epilepsy
Brain, 2012Co-Authors: Christian Vollmar, Gareth J Barker, Mark R Symms, Veena Kumari, Jonathan Omuircheartaigh, Pamela J ThompsonAbstract:Juvenile Myoclonic Epilepsy is the most common idiopathic generalized Epilepsy, characterized by frequent Myoclonic jerks, generalized tonic-clonic seizures and, less commonly, absences. Neuropsychological and, less consistently, anatomical studies have indicated frontal lobe dysfunction in the disease. Given its presumed thalamo–cortical basis, we investigated thalamo–cortical structural connectivity, as measured by diffusion tensor imaging, in a cohort of 28 participants with Juvenile Myoclonic Epilepsy and detected changes in an anterior thalamo–cortical bundle compared with healthy control subjects. We then investigated task-modulated functional connectivity from the anterior thalamic region identified using functional magnetic resonance imaging in a task consistently shown to be impaired in this group, phonemic verbal fluency. We demonstrate an alteration in task-modulated connectivity in a region of frontal cortex directly connected to the thalamus via the same anatomical bundle, and overlapping with the supplementary motor area. Further, we show that the degree of abnormal connectivity is related to disease severity in those with active seizures. By integrating methods examining structural and effective interregional connectivity, these results provide convincing evidence for abnormalities in a specific thalamo–cortical circuit, with reduced structural and task-induced functional connectivity, which may underlie the functional abnormalities in this idiopathic Epilepsy.
Maria Centeno - One of the best experts on this subject based on the ideXlab platform.
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motor co activation in siblings of patients with Juvenile Myoclonic Epilepsy an imaging endophenotype
Brain, 2014Co-Authors: Britta Wandschneider, Christian Vollmar, Mark R Symms, John S Duncan, Maria Centeno, Pamela J Thompson, Matthias J KoeppAbstract:Juvenile Myoclonic Epilepsy is a heritable idiopathic generalized Epilepsy syndrome, characterized by Myoclonic jerks and frequently triggered by cognitive effort. Impairment of frontal lobe cognitive functions has been reported in patients with Juvenile Myoclonic Epilepsy and their unaffected siblings. In a recent functional magnetic resonance imaging study we reported abnormal co-activation of the motor cortex and increased functional connectivity between the motor system and prefrontal cognitive networks during a working memory paradigm, providing an underlying mechanism for cognitively triggered jerks. In this study, we used the same task in 15 unaffected siblings (10 female; age range 18-65 years, median 40) of 11 of those patients with Juvenile Myoclonic Epilepsy (six female; age range 22-54 years, median 35) and compared functional magnetic resonance imaging activations with 20 age- and gender-matched healthy control subjects (12 female; age range 23-46 years, median 30.5). Unaffected siblings showed abnormal primary motor cortex and supplementary motor area co-activation with increasing cognitive load, as well as increased task-related functional connectivity between motor and prefrontal cognitive networks, with a similar pattern to patients (P < 0.001 uncorrected; 20-voxel threshold extent). This finding in unaffected siblings suggests that altered motor system activation and functional connectivity is not medication- or seizure-related, but represents a potential underlying mechanism for impairment of frontal lobe functions in both patients and siblings, and so constitutes an endophenotype of Juvenile Myoclonic Epilepsy.
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risk taking behavior in Juvenile Myoclonic Epilepsy
Epilepsia, 2013Co-Authors: Christian Vollmar, Britta Wandschneider, Maria Centeno, J Stretton, Jonathan OmuircheartaighAbstract:Objective Patients with Juvenile Myoclonic Epilepsy (JME) often present with risk-taking behavior, suggestive of frontal lobe dysfunction. Recent studies confirm functional and microstructural changes within the frontal lobes in JME. This study aimed at characterizing decision-making behavior in JME and its neuronal correlates using functional magnetic resonance imaging (fMRI).
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Risk‐taking behavior in Juvenile Myoclonic Epilepsy
Epilepsia, 2013Co-Authors: Britta Wandschneider, Christian Vollmar, Jonathan O'muircheartaigh, Gareth J Barker, Mark R Symms, Veena Kumari, Maria Centeno, J Stretton, Pamela J Thompson, John S DuncanAbstract:Objective Patients with Juvenile Myoclonic Epilepsy (JME) often present with risk-taking behavior, suggestive of frontal lobe dysfunction. Recent studies confirm functional and microstructural changes within the frontal lobes in JME. This study aimed at characterizing decision-making behavior in JME and its neuronal correlates using functional magnetic resonance imaging (fMRI).
J Stretton - One of the best experts on this subject based on the ideXlab platform.
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risk taking behavior in Juvenile Myoclonic Epilepsy
Epilepsia, 2013Co-Authors: Christian Vollmar, Britta Wandschneider, Maria Centeno, J Stretton, Jonathan OmuircheartaighAbstract:Objective Patients with Juvenile Myoclonic Epilepsy (JME) often present with risk-taking behavior, suggestive of frontal lobe dysfunction. Recent studies confirm functional and microstructural changes within the frontal lobes in JME. This study aimed at characterizing decision-making behavior in JME and its neuronal correlates using functional magnetic resonance imaging (fMRI).
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Risk‐taking behavior in Juvenile Myoclonic Epilepsy
Epilepsia, 2013Co-Authors: Britta Wandschneider, Christian Vollmar, Jonathan O'muircheartaigh, Gareth J Barker, Mark R Symms, Veena Kumari, Maria Centeno, J Stretton, Pamela J Thompson, John S DuncanAbstract:Objective Patients with Juvenile Myoclonic Epilepsy (JME) often present with risk-taking behavior, suggestive of frontal lobe dysfunction. Recent studies confirm functional and microstructural changes within the frontal lobes in JME. This study aimed at characterizing decision-making behavior in JME and its neuronal correlates using functional magnetic resonance imaging (fMRI).
