Causality Analysis to the Abnormal Subcortical–Cortical Connections in Idiopathic-Generalized Epilepsy
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ABSTRACT:
SUBMITTER: Qin Y
PROVIDER: S-EPMC9280354 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:The origin of neural hyperexcitability underlying idiopathic generalized epilepsy (IGE) is not known. The objective of this study is to identify evidence of hyperexcitability in precisely measured visual evoked responses and to understand the nature of changes in excitation and inhibition that lead to altered responses in human patients with IGE.Steady-state visual-evoked potentials (VEPs) to contrast reversing gratings were recorded over a wide range of stimulus contrast. VEPs were analyzed at the pattern reversal rate using spectral analysis. Ten patients with IGE and 13 healthy subjects participated. All subjects had normal visual acuity and had no history of photic-induced seizures or photoparoxysmal electroencephalograph (EEG) activity.At a group level, the amplitude of visual responses did not saturate at high stimulus contrast in patients, as it did in the control subjects. This reflects an abnormality in neuronal gain control. The VEPs did not have sufficient power to reliably distinguish patients from controls at an individual level. Parametric modeling using a standard gain control framework showed that the abnormality lay in reduced inhibition from neighboring neurons rather than increased excitatory response to the stimulus.Visual evoked responses reveal changes in a fundamental mechanism regulating neuronal sensitivity. These changes may give rise to hyperexcitability underlying generalized epilepsy.
| S-EPMC3183388 | biostudies-other
Project description:We identified 15q13.3 microdeletions encompassing the CHRNA7 gene in 12 of 1,223 individuals with idiopathic generalized epilepsy (IGE), which were not detected in 3,699 controls (joint P = 5.32 x 10(-8)). Most deletion carriers showed common IGE syndromes without other features previously associated with 15q13.3 microdeletions, such as intellectual disability, autism or schizophrenia. Our results indicate that 15q13.3 microdeletions constitute the most prevalent risk factor for common epilepsies identified to date.
| S-EPMC3026630 | biostudies-literature
Project description:ObjectivesTo evaluate the changes in prescription patterns in the treatment of idiopathic generalized epilepsy (IGE) due to updated treatment recommendations and to assess seizure outcomes of valproate compared to other antiseizure medications (ASMs), with emphasis on women with epilepsy (WWE).Materials and methodsRecords of IGE patients treated at Tampere University Hospital between 1 January 2009 and 31 December 2018 were retrospectively inspected. Data were analysed for two subgroups based on age and sex. Seizure control with reference to the efficacy of different ASMs and their combinations was examined for each subgroup.ResultsThe study compiled 263 subjects (166 females and 97 males). Of all patients, 72.6% remained seizure free. There was no difference in seizure control between sexes (OR 1.25, p = .48). Males used valproate more often than females while females used lamotrigine and levetiracetam more often than males. Lamotrigine and levetiracetam were used especially as monotherapy in WWE, and mostly as part of combination therapy in males. Valproate alternatives were found as effective as valproate when used in monotherapy in adults. Valproate remained the most used ASM in the paediatric subgroup.ConclusionsThe use of valproate has decreased in daily clinical use with the simultaneous increased use of alternative ASMs compared to our previous study. Decreasing use of valproate in WWE did not increase the risk of seizure recurrence; therefore, valproate alternatives could be considered as first-line ASMs for WWE. Overall, IGE patients demonstrated good clinical outcomes with valproate or other broad-spectrum ASMs as monotherapy.
| S-EPMC9299840 | biostudies-literature
Project description:Using a hypothesis-driven approach, subcortical and cortical regions implicated in anxiety disorders in the general population were examined in children with recent-onset epilepsy with versus without anxiety compared to controls. This study reports frequency of anxiety disorders while examining familial, clinical, and demographic variables associated with anxiety in children with epilepsy.Participants included 88 children with epilepsy aged 8-18 years: 25 with a current anxiety disorder and 63 children with epilepsy and no current anxiety disorder. Forty-nine controls without anxiety disorders were included. T1 volumetric magnetic resonance imaging (MRI) scans were collected; subcortical volumes and cortical thickness were computed using the FreeSurfer image analysis suite. Analyses focused on adjusted measures of subcortical volumes and cortical thickness.Relative to controls, larger left amygdala volumes were found in the Epilepsy with Anxiety group compared to the Epilepsy without Anxiety group (p = 0.027). In the hippocampus, there were no significant differences between groups. Examination of cortical thickness demonstrated that the Epilepsy with Anxiety group showed thinning in left medial orbitofrontal (p = 0.001), right lateral orbitofrontal (p = 0.017), and right frontal pole (p = 0.009). There were no differences between groups in age, sex, IQ, age of onset, medications, or duration of epilepsy. There were more family members with a history of anxiety disorders in the Epilepsy with Anxiety group compared to the Epilepsy without Anxiety group (p = 0.005).Anxiety is a common psychiatric comorbidity in children with recent-onset epilepsy with volumetric enlargement of the amygdala and thinner cortex in orbital and other regions of prefrontal cortex, suggesting structural abnormalities in brain regions that are part of the dysfunctional networks reported in individuals with anxiety disorders in the general population. These findings are evident early in the course of epilepsy, are not related to chronicity of seizures, and may be linked to a family history of anxiety and depressive disorders.
| S-EPMC4340751 | biostudies-literature
Project description:The amygdala processes valenced stimuli, influences emotion, and exhibits aberrant activity across anxiety disorders, depression, and PTSD. Interventions modulating amygdala activity hold promise as transdiagnostic psychiatric treatments. In 45 healthy participants, we investigated whether transcranial magnetic stimulation (TMS) elicits indirect changes in amygdala activity when applied to ventrolateral prefrontal cortex (vlPFC), a region important for emotion regulation. Harnessing in-scanner interleaved TMS/functional MRI (fMRI), we reveal that vlPFC neurostimulation evoked acute and focal modulations of amygdala fMRI BOLD signal. Larger TMS-evoked changes in the amygdala were associated with higher fiber density in a vlPFC-amygdala white matter pathway when stimulating vlPFC but not an anatomical control, suggesting this pathway facilitated stimulation-induced communication between cortex and subcortex. This work provides evidence of amygdala engagement by TMS, highlighting stimulation of vlPFC-amygdala circuits as a candidate treatment for transdiagnostic psychopathology. More broadly, it indicates that targeting cortical-subcortical structural connections may enhance the impact of TMS on subcortical neural activity and, by extension, subcortex-subserved behaviors.
| S-EPMC9217085 | biostudies-literature
Project description:AimsAlterations in neuronal activity and cerebral hemodynamics have been reported in idiopathic generalized epilepsy (IGE) patients, possibly resulting in neurovascular decoupling; however, no neuroimaging evidence confirmed this disruption. This study aimed to investigate the possible presence of neurovascular decoupling and its clinical implications in childhood IGE using resting-state fMRI and arterial spin labeling imaging.MethodsIGE patients and healthy participants underwent resting-state fMRI and arterial spin labeling imaging to calculate degree centrality (DC) and cerebral blood flow (CBF), respectively. Across-voxel CBF-DC correlations were analyzed to evaluate the neurovascular coupling within the whole gray matter, and the regional coupling of brain region was assessed with the CBF/DC ratio.ResultsThe study included 26 children with IGE and 35 sex- and age-matched healthy controls (HCs). Compared with the HCs, the IGE group presented lower across-voxel CBF-DC correlations, higher CBF/DC ratio in the right posterior cingulate cortex/precuneus, middle frontal gyrus, and medial frontal gyrus (MFG), and lower ratio in the left inferior frontal gyrus. The increased CBF/DC ratio in the right MFG was correlated with lower performance intelligence quotient scores in the IGE group.ConclusionChildren with IGE present altered neurovascular coupling, associated with lower performance intelligence quotient scores. The study shed a new insight into the pathophysiology of epilepsy and provided potential imaging biomarkers of cognitive performances in children with IGE.
| S-EPMC9873522 | biostudies-literature
Project description:Generalized tonic-clonic seizures are among the most dramatic physiological events in the nervous system. The brain regions involved during partial seizures with secondary generalization have not been thoroughly investigated in humans. We used single photon emission computed tomography (SPECT) to image cerebral blood flow (CBF) changes in 59 secondarily generalized seizures from 53 patients. Images were analysed using statistical parametric mapping to detect cortical and subcortical regions most commonly affected in three different time periods: (i) during the partial seizure phase prior to generalization; (ii) during the generalization period; and (iii) post-ictally. We found that in the pre-generalization period, there were focal CBF increases in the temporal lobe on group analysis, reflecting the most common region of partial seizure onset. During generalization, individual patients had focal CBF increases in variable regions of the cerebral cortex. Group analysis during generalization revealed that the most consistent increase occurred in the superior medial cerebellum, thalamus and basal ganglia. Post-ictally, there was a marked progressive CBF increase in the cerebellum which spread to involve the bilateral lateral cerebellar hemispheres, as well as CBF increases in the midbrain and basal ganglia. CBF decreases were seen in the fronto-parietal association cortex, precuneus and cingulate gyrus during and following seizures, similar to the 'default mode' regions reported previously to show decreased activity in seizures and in normal behavioural tasks. Analysis of patient behaviour during and following seizures showed impaired consciousness at the time of SPECT tracer injections. Correlation analysis across patients demonstrated that cerebellar CBF increases were related to increases in the upper brainstem and thalamus, and to decreases in the fronto-parietal association cortex. These results reveal a network of cortical and subcortical structures that are most consistently involved in secondarily generalized tonic-clonic seizures. Abnormal increased activity in subcortical structures (cerebellum, basal ganglia, brainstem and thalamus), along with decreased activity in the association cortex may be crucial for motor manifestations and for impaired consciousness in tonic-clonic seizures. Understanding the networks involved in generalized tonic-clonic seizures can provide insights into mechanisms of behavioural changes, and may elucidate targets for improved therapies.
| S-EPMC2724910 | biostudies-literature
Project description:Idiopathic generalized epilepsy (IGE) is an epilepsy form without an underlying brain lesion or neurological indication or symptom. Recent investigations on the genetic origins of IGE and its subtypes report that certain mutations of various ion and non-ion channels genes in the central nervous system may be associated with IGE.In this study we evaluated the relation between IGE and S430Y polymorphism in EFHC2 gene in a Turkish population.The study enrolled 96 healthy volunteers (47 male, 49 female), served as controls, and 96 IGE patients (41 male, 55 female), IGE diagnosis was confirmed in the neurology department. DNA extractions were performed. The presence of S430Y polymorphism in the exon 9 of EFHC2 gene were analyzed by Real-Time PCR. The findings obtained from the control and patient groups were compared.In the patient group there was one heterozygous male with 685 T>C mutation. In the control group, there were two objects with 685 T>C mutation; one heterozygous male, one heterozygous female. 662 G>A mutation was determined in neither controls nor patients.In our series of 96 IGE patients and 96 healthy controls, there was no relation between S430Y polymorphism in EFHC2 gene and IGE presence.
| S-EPMC4765430 | biostudies-literature
Project description:The objective of this study was to investigate the relationship between the focal discharges sometimes observed in the electroencephalogram of patients with idiopathic generalized epilepsies and subtle structural magnetic resonance imaging abnormalities. The main hypothesis to be assessed is that focal discharges may arise from areas of structural abnormality which can be detected by quantitative neuroimaging. Focal discharges were used for quantitative electroencephalogram source detection. Neuroimaging investigations consisted of voxel-based morphometry and region of interest volumetry. For voxel-based morphometry, volumetric MRI were acquired and processed. The images of each patient were individually compared with a control group. Statistical analysis was used to detect differences in gray matter volumes. Region of interest-based morphometry was automatically performed and used essentially to confirm voxel-based morphometry findings. The localization of the focal discharges on the electroencephalogram was compared to the neuroimaging results. Twenty-two patients with idiopathic generalized epilepsies were evaluated. Gray matter abnormalities were detected by voxel-based morphometry analysis in 77% of the patients. There was a good concordance between EEG source detection and voxel-based morphometry. On average, the nearest voxels detected by these methods were 19 mm (mm) apart and the most statistically significant voxels were 34 mm apart. This study suggests that in some cases subtle gray matter abnormalities are associated with focal epileptiform discharges observed in the electroencephalograms of patients with idiopathic generalized epilepsies.
| S-EPMC6870673 | biostudies-literature
Project description: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.
| S-EPMC9381751 | biostudies-literature