bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Brief Period of Epileptiform Activity Strengthens Excitatory Synapses in the Rat Hippocampus in Vitro
Authors: Debanne Dominique , Thompson Scott M. , Gähwiler Beat H. 
Published: February 2006

Summary:  Purpose: We examined here whether a very short period of epileptiform activity could produce lasting modifications of synaptic strength and network properties in the rat hippocampus in vitro. Methods: Synaptic transmission at CA3‐CA1 and at CA3‐CA3 pyramidal cell synapses was monitored in hippocampal slice cultures before and after a very brief episode of epileptiform activity (20–180 s) induced with bicuculline methochloride. Results: We show here that a brief period of epileptiform activity induces long‐lasting potentiation of glutamatergic transmission at CA3‐CA1 and at CA3‐CA3 pyramidal cell synapses. This potentiation also was observed at synapses formed by pairs of monosynaptically connected neurons. It was dependent on N‐methyl‐d‐aspartate (NMDA) receptors, occluded classic long‐term potentiation, and could be depotentiated by low‐frequency stimulation at 3 Hz. Recruitment of polysynaptic pathways within area CA3 was facilitated after epileptiform activity indicating that the induced potentiation enhanced overall hippocampal network excitability. Conclusions: These changes in synaptic transmission may contribute to the genesis of epilepsy and to seizure‐associated memory deficits.
Reeler Homozygous Mice Exhibit Enhanced Susceptibility to Epileptiform Activity
Authors: Patrylo Peter R. , Browning Ronald A. , Cranick Scott 
Published: February 2006

Summary:  Purpose: Seizures are observed frequently in humans with diffuse neuronal migration disorders. The reeler mutant mouse also exhibits a diffuse disruption of migration, yet no proepileptic phenotype has been reported for this model. Whether this disparity reflects a phenotypic difference that can be used to delineate the mechanisms associated with increasing seizure susceptibility or reflects a paucity of knowledge is unclear. Consequently, this study examined whether seizure susceptibility is altered in reeler mutant mice. Methods: In vivo (minimal electroshock delivered transcorneally) and in vitro techniques (field‐potential recordings in neocortical and hippocampal brain slice preparations exposed to bicuculline methiodide) were used to determine whether the susceptibility to epileptiform activity is enhanced in reeler homozygous mice relative to controls. Adult (3–7 months) male reeler homozygotes (rl/rl) and controls (+/?) were identified based on their behavioral phenotype and were used in all experiments. Results: Minimal electroshock revealed that rl/rl mice, compared with controls, exhibited a lower threshold for electroshock‐induced seizures (4.5 ± 0.52 vs. 6.7 ± 0.35 mA), and a higher incidence of behavioral seizures (median seizure score, class 4 vs. class 0) when animals were subjected to a 5‐mA electroshock stimulus. Additionally, neocortical and hippocampal slices from rl/rl mice were more likely to generate spontaneous epileptiform activity after bicuculline application, compared with controls, and the duration of the epileptiform events elicited in 10–30 μM bicuculline was longer in slices from rl/rl mice. Conclusions: These data demonstrate that rl/rl mice have enhanced seizure susceptibility that is in part intrinsic to the malformed neocortex and hippocampus. Thus in contrast to prior belief, most animal models of diffuse neuronal migration disorders do exhibit a proepileptic phenotype.
Diacylglycerol Kinase Epsilon Modulates Rapid Kindling Epileptogenesis
Authors: Musto Alberto , Bazan Nicolas G. 
Published: February 2006

Summary: Purpose:Diacylglycerol kinase epsilon (DGKε) regulates seizure susceptibility and long‐term potentiation through arachidonoyl‐inositol lipid signaling. We studied the significance of arachidonoyl‐diacylglycerol (20:4 DAG) in epileptogenesis in DGKε‐deficient mice undergoing rapid kindling epileptogenesis.Methods:Tripolar electrode units were implanted in right dorsal hippocampi of male DGKε+/+and DGKε−/−mice. Ten days after surgery, kindling was achieved by stimulating 6 times daily for 4 days with a subconvulsive electrical stimulation (10‐s train of 50‐Hz biphasic pulses, 75–200 μA amplitude) at 30‐min intervals. After 1 week, mice were rekindled. EEGs were recorded and analyzed to characterize epileptogenic events as spikes, sharp waves, or abnormal amplitudes and rhythms. Right hippocampi were analyzed by histology [Timm's staining, neuropeptide Y (NPY) and glial fibrillary acidic protein immunoreactivity], and for DNA fragmentation (TUNEL).Results:DGKε−/−mice had significantly fewer motor seizure and epileptic events compared with DGKε+/+mice from the second day of stimulation. These differences were maintained during rekindling. DGKε−/−mice also exhibited low‐amplitude spike–wave complexes, short spreading depression, and predominant lower‐frequency (1–4 Hz) bands throughout stimulation, whereas DGKε+/+mice exhibited increased high‐frequency bands (4–8 Hz; 8–15 Hz) from the second day of stimulation, as determined by power spectral analysis. DGKε−/−mice displayed no sprouting in the supragranular area or NPY inmunoreactivity in the hilus and had weak astrocyte reactivation in all hippocampal areas. No TUNEL‐positive cells were detected in any group of mice.Conclusions:DGKε modulates kindling epileptogenesis through inositol lipid signaling. Because arachidonate‐containing diacylglycerol phosphorylation to phosphatidic acid is selectively blocked in DGKε−/−mice, we postulate that the shortage of arachidonoyl‐moiety inositol lipids and/or the messengers derived thereof is a key signaling event in epileptogenesis.
Decrease of Hippocampal GABAB Receptor–Mediated Inhibition after Hyperthermia‐induced Seizures in Immature Rats
Authors: Tsai Min‐Lan , Leung L. Stan 
Published: February 2006

Summary:  Purpose: Whether febrile seizures have detrimental consequences on the brain is still controversial. We hypothesized that neuronal inhibition in the hippocampus is altered after hyperthermia‐induced seizures in immature rats. Methods: Rats were given a single seizure by a heat lamp on postnatal day (PND) 15, or repeated seizures by heated air on PND 13 to 15. Fourteen or 30 days after the seizure(s), laminar field potentials were recorded by 16‐channel silicon probes in CA1 and the dentate gyrus (DG), in response to the paired‐pulse stimulation of the CA3 and medial perforant path, and analyzed as current source density. γ‐Aminobutyric acid (GABA)B‐receptor antagonist CGP35348 was injected intracerebroventricularly (icv). Results: At 14 but not at 30 days after a single or after repeated hyperthermia‐induced seizures, paired‐pulse facilitation (PPF) of the CA1 population spikes at 100 to 200 ms interpulse intervals (IPIs) was significantly increased in seizure as compared with control rats, irrespective of the types of induced seizures. CGP35348 icv also resulted in PPF at 100 to 200 ms IPIs in CA1 of control rats, but CGP35348 had no effect on PPF in seizure rats. At 30 days after repeated seizures, paired‐pulse inhibition in the DG was significantly increased at 30‐ms IPI, and PPF was increased at 200‐ms IPI. CGP35348 increased paired‐pulse inhibition in the DG in repeated‐seizure rats but not in control rats. Conclusions:We conclude that hyperthermia‐induced seizures in immature rats induced a decrease of GABAB receptor–mediated inhibition in CA1 and DG that lasted ≥14 to 30 days after hyperthermic seizure(s).
Neocortical Microenvironment in Patients with Intractable Epilepsy: Potassium and Chloride Concentrations
Authors: Gorji Ali , Stemmer Nina , Rambeck Bernhard , Jürgens Uwe , May Theodor , Pannek Heinz Wolfgang , Behne Friedrich , Ebner Alois , Straub Hiedrun , Speckmann Erwin‐Josef 
Published: February 2006

Summary:  Purpose: The regulation of extracellular ion concentrations plays an important role in neuronal function and epileptogenesis. Despite the many studies into the mechanisms of epileptogenesis in human experimental models, no data are available regarding the fluctuations of extracellular potassium ([K+]o) and chloride ([Cl−]o) concentrations, which could underlie seizure susceptibility in human chronically epileptic tissues in vivo. Methods: By using cerebral microdialysis during surgical resection of epileptic foci, the basic [K+]o and [Cl−]o as well as their changes after epicortical electric stimulation were studied in samples of dialysates obtained from 11 patients by ion‐selective microelectrodes. Results: The mean basal values of [K+]o and [Cl−]o in all patients were 3.83 ± 0.08 mM and 122.9 ± 2.6 mM, respectively. However, significant differences were observed in the basal levels of both [K+]o and [Cl−]o between different patients. Statistically, no correlation was found between basal [K+]o or [Cl−]o and electrocorticogram (ECoG) spike activity, but in one patient, dramatically lowered baseline [Cl−]o was accompanied by enhanced ECoG spike activity. Application of epicortical electrical stimulation increased [K+]o but not [Cl−]o in all cases. According to the velocity as well as spatial distribution of [K+]o reduction to the prestimulation levels, three different types of responses were observed: slow decline, fast decline, and slow and fast declines at adjacent sites. Conclusions: These data may represent abnormalities in ion homeostasis of the epileptic brain.
Ginkgo biloba Use in Nursing Home Elderly with Epilepsy or Seizure Disorder
Authors: Harms Susan L. , Garrard Judith , Schwinghammer Paul , Eberly Lynn E. , Chang Yanping , Leppik Ilo E. 
Published: February 2006

Summary:  Purpose: Ginkgo biloba, among the most widely used herbs, possesses the capacity both to induce and to inhibit seizures. The purpose of this study was to describe the prevalence of ginkgo and other common herb prescribing in a sample of nursing home (NH) elderly diagnosed with epilepsy/seizure (Epi/Sz) disorder and to determine demographic, clinical, and functional factors associated with ginkgo use. Methods: This was a 1‐year prevalence study of 68,403 NH residents living in 557 nursing facilities throughout the United States. Results: Overall, herb use in the NHs was very low (0.41%). Ginkgo was prescribed 162 times, more than any other herb. St. John's wort was prescribed 40 times; garlic, 29 times; and all others, <20 times, for a total of 307 herb orders. Among all residents with an herb order, ginkgo was prescribed for 61.9% of residents with an Epi/Sz diagnosis and 58.0% (p = 0.820) of residents without an Epi/Sz diagnosis. Dementia, educational level, and the interaction of age group with cognitive impairment were all significantly associated with herb use among Epi/Sz residents. Cognitive impairment and the interaction of Epi/Sz disorder with dementia were associated specifically with ginkgo use. Conclusions: Ginkgo is the most frequently prescribed herb in this population in which >50% of all herb orders were written for ginkgo. The concern with ginkgo use among elderly with Epi/Sz is the lack of standardization that characterizes ginkgo products. In the absence of standardization, the likelihood is increased that ginkgo products may be adulterated with the Ginkgo biloba plant parts most commonly associated with seizure provocation.
Temporal and Extratemporal BOLD Responses to Temporal Lobe Interictal Spikes
Authors: Kobayashi Eliane , Bagshaw Andrew P. , Bénar Christian‐George , Aghakhani Yahya , Andermann Frederick , Dubeau François , Gotman Jean 
Published: February 2006

Summary: Purpose:Simultaneous EEG and functional MRI (fMRI) allows measuring metabolic changes related to interictal spikes. Our objective was to investigate blood oxygenation level–dependent (BOLD) responses to temporal lobe (TL) spikes by using EEG‐fMRI recording.Methods:We studied 35 patients who had a diagnosis of temporal lobe epilepsy (TLE) and active TL spiking on routine scalp EEG recording. Two‐hour sessions of continuous EEG‐fMRI were recorded, and spikes were identified after offline artifact removal and used as events in thefMRI analysis. Each type of spike was analyzed separately, as one EEG‐fMRI study. We determined significant (p < 0.05) positive (activation) and negative (deactivation) BOLD responses for each study.Results:Twenty‐seven patients had spikes during scanning (19 unilateral and eight bilateral). From a total of 35fMRI studies, 29 (83%) showed BOLD responses: 14 had both activations and deactivations; 12, activations only; and three, deactivations only. Six (17%) showed no responses. Nineteen studies had mainly neocortical TL activation: Sixteen (84%) of 19 concordant with spikes, 12 of 16 with concomitant activation of the contralateral TL, and 16 of 19 with additional extratemporal activation; few showed exclusively mesial TL activation. Seventeen studies showed deactivation, either extratemporal plus temporal (n = 8) or exclusively extratemporal (n = 9).Conclusions:BOLD responses to TL spikes occurred in 83% of studies, predominated in the spiking temporal lobe, and manifested as activation or deactivation. Responses often involved the contralateral homologous cortex at the time of unilateral spikes and were frequently observed in extratemporal regions, suggesting that TL epileptic spikes can affect neuronal activity at a distance through synaptic connections.
Single and Multiple Clusters of Magnetoencephalographic Dipoles in Neocortical Epilepsy: Significance in Characterizing the Epileptogenic Zone
Authors: Oishi Makoto , Kameyama Shigeki , Masuda Hiroshi , Tohyama Jun , Kanazawa Osamu , Sasagawa Mutsuo , Otsubo Hiroshi 
Published: February 2006

Summary:  Purpose: To characterize the epileptogenic zone in neocortical epilepsy (NE) by using magnetoencephalography (MEG). Methods: We defined and compared locations of single and multiple clusters of equivalent current dipoles (ECDs) for interictal spikes with MRI findings, ictal‐onset zones (IOZs) from subdural electroencephalography (SDEEG), resected areas, and postsurgical outcomes of 20 patients who underwent cortical resection for medically intractable NE. Results: Fourteen patients had single clusters; six had multiple clusters. Overlap of clusters and IOZs defined group A (nine patients), in which a single cluster coincided with the IOZ; group B1 (four patients), in which a single cluster was within or partially overlapped the IOZ; group B2 (five patients), in which multiple‐cluster sections overlapped IOZs; group C (two patients; one single; one multiple), in which no overlap was seen. More single clusters (nine of 14) than multiple clusters (none of six) coincided with the IOZ (p = 0.014). More patients with single clusters (10 of 14) than patients with multiple clusters (one of six) had seizure‐free outcomes (p = 0.049). Eight of nine patients in group A, versus three of 11 in groups B1, B2, and C, achieved seizure‐free outcomes (p = 0.0098). Correlations between MRI findings and postsurgical outcomes were not statistically significant; eight of 13 patients with single lesions, one of four with no lesions, and two of three with multifocal lesions had seizure‐free outcomes. Conclusions: In neocortical epilepsy, MEG ECD clusters correlated with SDEEG IOZs. Single clusters indicated discrete epileptogenic zones that required complete resection for seizure‐free outcome. Multiple clusters necessitated that the multiple or extensive epileptogenic zones be completely identified and delineated by SDEEG.
Epileptogenicity of Supratentorial Medullary Venous Malformation
Authors: Morioka Takato , Hashiguchi Kimiaki , Nagata Shinji , Miyagi Yasushi , Yoshida Fumiaki , Mihara Futoshi , Sakata Ayumi , Sasaki Tomio 
Published: February 2006

Summary:  Purpose: The purpose of this study was to evaluate the epileptogenicity of supratentorial medullary venous malformation (MVM). Special consideration was given to any associations with intracerebral hemorrhage with or without other vascular malformations, including cavernous angioma (CA). Methods: In total, 10 patients with angiographically or histologically verified MVMs were examined. The patients were divided into two groups with or without intracerebral hemorrhage, and their clinical, neuroradiologic, and interictal and ictal EEG findings were reviewed retrospectively. Results: Although three of five patients in the nonhemorrhagic group had epilepsy, no topographic concordance was found between the MVM location and the EEG focus. On the contrary, in four of five patients in the hemorrhagic group, epilepsy developed, and topographic concordance between the hemorrhagic MVM location and the EEG focus was noted. One patient with a hemorrhagic MVM and an associated CA in the hippocampus had electroclinical pictures of intractable medial temporal lobe epilepsy on this side. Conclusions: Although a supratentorial MVM itself is not epileptogenic, the development of an intracerebral hemorrhage may cause epilepsy. In particular, an associated CA may be highly epileptogenic.
Extended, One‐stage Callosal Section for Treatment of Refractory Secondarily Generalized Epilepsy in Patients with Lennox–Gastaut and Lennox‐like Syndromes
Authors: Cukiert Arthur , Burattini Jose Augusto , Mariani Pedro Paulo , Câmara Ródio Brandão , Seda Lauro , Baldauf Cristine Mella , Argentoni Meire , Baise‐Zung Carla , Forster Cássio Roberto , Mello Valeria Antakli 
Published: February 2006

Summary: Purpose:We report on the efficacy and safety of extended one‐stage callosal section performed in a large and homogeneous series of patients.Methods:Seventy‐six patients with Lennox–Gastaut (n = 28) and Lennox‐like (n = 48) syndrome were studied (42 male patients; mean age, 11.2 years). All patients had multiple seizure types per day, including atonic, tonic–clonic, atypical absence, myoclonic, and tonic seizures. All of them were developmentally impaired. The EEG showed intense secondary bilateral synchrony in all of them. All patients were submitted to an extended, one‐stage, callosal section, leaving only the splenium intact. Mean follow‐up time was 4.7 years.Results:Worthwhile improvement (>50%) was noted in 69 of 76 patients; 52 patients had a ≥90% reduction in seizure frequency. Seven patients were seizure free after surgery. The seizure patterns most responsive to surgery were atonic (92%), atypical absence (82%), and tonic–clonic (57%) seizures. All patients had some degree of a transient acute postoperative disconnection syndrome. A consistent increase in attention level was observed postoperatively.Conclusions:We report one of the larger homogeneous series of patients submitted to callosotomy and are the first to report on the effectiveness and safety of performing extended callosal section in a single stage in this patient group. Extended callosal section should be considered a good palliative surgical option for suitable candidates. The increase in attention level was as useful as seizure control in improving quality of life of these patients.
Seizure Recurrence and Risk Factors after Antiepilepsy Drug Withdrawal in Children with Brain Tumors
Authors: Khan Raja B. , Onar Arzu 
Published: February 2006

Summary: Purpose:To study seizure outcome after antiepilepsy drug (AED) withdrawal in brain tumor patients and to analyze risk factors for seizure recurrence.Methods:Brain tumor patients with seizures and at least one attempt at AED discontinuation were identified from the hospital database and neurology clinic records. After defining study variables, patient charts were abstracted for clinical and demographic data. Statistical analyses used log‐rank tests and multivariable Cox proportional hazards models.Results:Sixty‐two patients discontinued AEDs at a median time of 5.6 years from the first seizure (range, 1.2–19.6 years). Median time since AED withdrawal was 2.3 years (range, 0.4–15.1 years). Seizures recurred in 17 (27%) patients within a median time of 0.8 years (range, 0.06–7.7 years). Median seizure‐free period before AED withdrawal was 1.3 years (range, 0.1–11 years). More than one tumor resection and whole‐brain radiation treatment (WBRT) were associated with seizure recurrence, whereas posterior fossa tumor location was correlated with reduced seizure recurrence risk. At seizure recurrence, control was easily reestablished in 10 patients with AED reinstitution and after dose adjustment in five; two patients with poor drug compliance continue to have seizures. In 48 patients who had an EEG before AED withdrawal, spikes or slow waves did not correlate with seizure recurrence.Conclusions:AED withdrawal can be successfully achieved in majority of carefully selected patients. WBRT and multiple tumor resections seem to be associated with an increased hazard for seizure recurrence.
Epilepsy in Menkes Disease: Analysis of Clinical Stages
Authors: Bahi‐Buisson Nadia , Kaminska Anna , Nabbout Rima , Barnerias Christine , Desguerre Isabelle , De Lonlay Pascale , Mayer Michele , Plouin Perrine , Dulac Olivier , Chiron Catherine 
Published: February 2006

Summary: Purpose:Epilepsy is one of the main features of Menkes disease (MD), although it is not described in depth. To determine the spectrum of epilepsy, we studied its main characteristics.Methods:Based on clinical charts, we retrospectively analyzed the evolution of electroclinical features of 12 patients with confirmed MD.Results:Epilepsy could be divided into three periods: (a) an early stage (median age, 3 months), characterized by focal clonic status epilepticus, usually triggered by fever (10 patients). Ictal EEG showed runs of slow spike–waves and slow waves in the posterior regions, and interictal EEG multifocal and polymorphic slow waves (three cases), or mixed slow spike–waves and slow waves (seven cases). Partial seizure control was obtained in nine patients during 5.9 months; (b) an intermediate stage (median age, 10 months) with intractable infantile spasms (11 patients) in which interictal EEG demonstrated modified hypsarrhythmia (seven cases), diffuse irregular slow waves and spike–waves (four cases). Six patients died at the median age of 15 months; and (c) a late stage in the six remaining patients (median age, 25 months), with multifocal seizures, tonic spasms, and myoclonus in four patients, whereas two patients became seizure free. Interictal EEG showed multifocal high‐amplitude activity, mixed with irregular slow waves in all six cases. These patients died at the median age of 3.6 years.Conclusions:Based on a relatively large series of MD patients with a quite prolonged survival, we individualized three successive periods in the course of epilepsy: early focal status, then infantile spasms, and then myoclonic and multifocal epilepsy after age 2 years.