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Spike-and-wave discharges (SWDs) and sleep spindles are characteristic electroencephalographic (EEG) hallmarks of absence seizures and nonrapid eye movement sleep, respectively. They are commonly generated by the cortico-thalamo-cortical network including the thalamic reticular nucleus (TRN). It has been reported that SWD development is accompanied by a decrease in sleep spindle density in absence seizure patients and animal models. However, whether the decrease in sleep spindle density precedes, coincides with, or follows, the SWD development remains unknown. To clarify this, we exploited Pvalb-tetracycline transactivator (tTA)::tetO-ArchT (PV-ArchT) double-transgenic mouse, which can induce an absence seizure phenotype in a time-controllable manner by expressing ArchT in PV neurons of the TRN. In these mice, EEG recordings demonstrated that a decrease in sleep spindle density occurred 1 week before the onset of typical SWDs, with the expression of ArchT. To confirm such temporal relationship observed in these genetic model mice, we used a gamma-butyrolactone (GBL) pharmacological model of SWDs. Prior to GBL administration, we administered caffeine to wild-type mice for 3 consecutive days to induce a decrease in sleep spindle density. We then administered low-dose GBL, which cannot induce SWDs in normally conditioned mice but led to the occurrence of SWDs in caffeine-conditioned mice. These findings indicate a temporal relationship in which the decrease in sleep spindle density consistently precedes SWD development. Furthermore, the decrease in sleep spindle activity may have a role in facilitating the development of SWDs. Our findings suggest that sleep spindle reductions could serve as early indicators of seizure susceptibility.

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OBJECTIVES: Absence seizures impair psychosocial function, yet their detailed neuronal basis remains unknown. Recent work in a rat model suggests that cortical arousal state changes prior to seizures and that single neurons show diverse firing patterns during seizures. Our aim was to extend these investigations to a mouse model with studies of neuronal activity and arousal state to facilitate future fundamental investigations of absence epilepsy. METHODS: We performed in vivo extracellular single unit recordings on awake head-fixed C3H/HeJ mice. Mice were implanted with tripolar electrodes for cortical electroencephalography (EEG). Extracellular single unit recordings were obtained with glass micropipettes in the somatosensory barrel cortex, while animals ambulated freely on a running wheel. Signals were digitized and analyzed during seizures and at baseline. RESULTS: Neuronal activity was recorded from 36 cortical neurons in 19 mice while EEG showed characteristic 7-8 Hz spike-wave discharges. Different single neurons showed distinct firing patterns during seizures, but the overall mean population neuronal firing rate during seizures was no different from pre-seizure baseline. However, the rhythmicity of neuronal firing during seizures was significantly increased (p < 0.001). In addition, beginning 10s prior to seizure initiation, we observed a progressive decrease in cortical high frequency (>40 Hz) EEG and an increase in lower frequency (1-39 Hz) activity suggesting decreased arousal state. SIGNIFICANCE: We found that the awake head-fixed C3H/HeJ mouse model demonstrated rhythmic neuronal firing during seizures, and a decreased cortical arousal state prior to seizure onset. Unlike the rat model we did not observe an overall decrease in neuronal firing during seizures. Similarities and differences across species strengthen the ability to investigate fundamental key mechanisms. Future work in the mouse model will identify the molecular basis of neurons with different firing patterns, their role in seizure initiation and behavioral deficits, with ultimate translation to human absence epilepsy.

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KCNB1, on human chromosome 20q13.3, encodes the alpha subunit of the Kv2.1 voltage gated potassium channel. Kv2.1 is ubiquitously expressed throughout the brain and is critical in controlling neuronal excitability, including in the hippocampus and pyramidal neurons. Human KCNB1 mutations are known to cause global development delay or plateauing, epilepsy, and behavioral disorders. Here, we report a sibling pair with developmental delay, absence seizures, autism spectrum disorder, hypotonia, and dysmorphic features. Whole exome sequencing revealed a heterozygous variant of uncertain significance (c. 342 C>A), p. (S114R) in KCNB1, encoding a serine to arginine substitution (S114R) in the N-terminal cytoplasmic region of Kv2.1. The siblings' father demonstrated autistic features and was determined to be an obligate KCNB1 c. 342 C>A carrier based on familial genetic testing results. Functional investigation of Kv2.1-S114R using cellular electrophysiology revealed slowing of channel activation, deactivation, and inactivation, resulting in increased net current after longer membrane depolarizations. To our knowledge, this is the first study of its kind that compares the presentation of siblings each with a KCNB1 disorder. Our study demonstrates that Kv2.1-S114R has profound cellular and phenotypic consequences. Understanding the mechanisms underlying KCNB1-linked disorders aids clinicians in diagnosis and treatment and provides potential therapeutic avenues to pursue.

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Childhood absence epilepsy is one of the most prevalent pediatric epilepsy syndromes, but diagnostic delay is common and consequential. Childhood absence epilepsy is diagnosed by history and physical examination including hyperventilation with electroencephalography (EEG) used to confirm the diagnosis. Hyperventilation produces generalized spike-wave discharges on EEG in >90% of patients with childhood absence epilepsy and provokes clinical absence seizures consisting of brief loss of consciousness typically within 90 seconds. Child neurologists report a high volume of referrals for children with "staring spells" that strain already limited health care resources. Resources are further strained by the use of EEG for monitoring antiseizure medication effectiveness with unclear benefit. In this review, we examine the safety and efficacy of hyperventilation activation as a tool for the diagnosis and management of childhood absence seizures.

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OBJECTIVES: Vitamin B7(biotin) is not synthesized in our body and is retrieved from some food products like eggs, liver, pork and leafy vegetables and as well as microbes of gut. Deficiency of biotin majorly leads to loss of hair, rashes over skin, lethargy and seizures. It is noted that biotin is an anti-oxidant and negates free radical effects. Biotin is also involved in carbon dioxide metabolism and it might alter seizure threshold. Studies also suggest its effect on lipid metabolism as well. So, the primary objective of this study was to assess the efficacy of biotin in maximal electric shock (MES) induced generalized tonic-clonic seizures (GTCS) and pentylenetetrazole (PTZ) induced absence seizures. The secondary objective is to study the effect of combined treatment of biotin and sodium valproate on seizures as well as plasma lipid profile in rats. METHODS: In our study 30 albino Wistar rats each were used in MES and PTZ model respectively. 30 rats were divided equally into following groups: I - distilled water (negative control) II - distilled water (positive control) III - sodium valproate (300 mg/kg) IV - biotin (10 mg/kg/day) V - biotin (10 mg/kg) + sodium valproate (150 mg/kg). RESULTS: We observed that the tonic hind limb extension was significantly reduced in the treatment group in MES model. Nitric oxide levels were also seen raised in combination group in MES model and all the treated groups in PTZ model. Biotin treated group showed increased high-density lipoproteins and reduced low density lipoproteins and triglycerides. CONCLUSIONS: Biotin had an additive effect to sodium valproate in both the models of epilepsy in rats. Further, it was also able to counteract hyperlipidemia cause by sodium valproate.

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The persistence of typical absence seizures (AS) in adolescence and adulthood may reduce the quality of life of patients with genetic generalized epilepsies (GGEs). The prevalence of drug resistant AS is probably underestimated in this patient population, and treatment options are relatively scarce. Similarly, atypical absence seizures in developmental and epileptic encephalopathies (DEEs) may be unrecognized, and often persist into adulthood despite improvement of more severe seizures. These two seemingly distant conditions, represented by typical AS in GGE and atypical AS in DEE, share at least partially overlapping pathophysiological and genetic mechanisms, which may be the target of drug and neurostimulation therapies. In addition, some patients with drug-resistant typical AS may present electroclinical features that lie in between the two extremes represented by these generalized forms of epilepsy.

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BAER-101 (formerly AZD7325) is a selective partial potentiator of α2/3-containing γ-amino-butyric acid A receptors (GABAARs) and produces minimal sedation and dizziness. Antiseizure effects in models of Dravet and Fragile X Syndromes have been published. BAER-101 has been administered to over 700 healthy human volunteers and patients where it was found to be safe and well tolerated. To test the extent of the antiseizure activity of BAER-1010, we tested BAER-101 in the Genetic Absence Epilepsy Rats from Strasbourg (GAERS) model, a widely used and translationally relevant model. GAERS rats with recording electrodes bilaterally located over the frontal and parietal cortices were used. Electroencepholographic (EEG) signals in freely moving awake rats were analyzed for spike-wave discharges (SWDs). BAER-101 was administered orally at doses of 0.3-100 mg/kg and diazepam was used as a positive control using a cross-over protocol with a wash-out period between treatments. The number of SWDs was dose-dependently reduced by BAER-101 with 0.3 mg/kg being the minimally effective dose (MED). The duration of and total time in SWDs were also reduced by BAER-101. Concentrations of drug in plasma achieved an MED of 10.1 nM, exceeding the Ki for α2 or α3, but 23 times lower than the Ki for α5-GABAARs. No adverse events were observed up to a dose 300× MED. The data support the possibility of antiseizure efficacy without the side effects associated with other GABAAR subtypes. This is the first report of an α2/3-selective GABA PAM suppressing seizures in the GAERS model. The data encourage proceeding to test BAER-101 in patients with epilepsy.

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Atypical absence seizures are generalized non-convulsive seizures that often occur in children with cognitive impairment. They are common in refractory epilepsy and have been recognized as one of the hallmarks of developmental epileptic encephalopathies. Notably, pathogenic variants associated with AAS, such as GABRG2, GABRG3, SLC6A1, CACNB4, SCN8A, and SYNGAP1, are also linked to developmental epileptic encephalopathies. Atypical absences differ from typical absences in that they are frequently drug-resistant and the prognosis is dependent on the etiology or related epileptic syndromes. To improve clinicians' understanding of atypical absences and provide novel perspectives for clinical treatment, we have reviewed the electro-clinical characteristics, etiologies, treatment, and prognosis of atypical absences, with a focus on the etiology of advancements in gene variants, shedding light on potential avenues for improved clinical management.

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AIM: The Genetic Absence Epilepsy Rats from Strasbourg (GAERS) are an inbred polygenic model of childhood absence epilepsy (CAE), which, as their non-epileptic control (NEC) rats, are derived from Wistar rats. While the validity of GAERS in reproducing absence seizures is well established, its use as a model for CAE psychiatric comorbidities has been subject to conflicting findings. Differences in colonies, experimental procedures, and the use of diverse controls from different breeders may account for these disparities. Therefore, in this study, we compared GAERS, NEC, and Wistar bred in the same animal facility with commercially available Wistar (Cm Wistar) as a third control. METHODS: We performed hole board (HB) and elevated plus maze (EPM) tests that were analyzed with standard quantitative and T-pattern analysis in male, age-matched Cm Wistar and GAERS, NEC, and Wistar, bred under the same conditions, to rule out the influence of different housing factors and provide extra information on the structure of anxiety-like behavior of GAERS rats. RESULTS: Quantitative analysis showed that GAERS and NEC had similar low anxiety-like behavior when compared to Cm Wistar but not to Wistar rats, although a higher hole-focused exploration was revealed in NEC. T-pattern analysis showed that GAERS, NEC, and Wistar had a similar anxiety status, whereas GAERS and NEC exhibited major differences with Cm Wistar but not Wistar rats. EPM results indicated that GAERS and NEC also have similar low anxiety compared to Cm Wistar and/or Wistar rats. Nevertheless, the analysis of the T-pattern containing open-arm entry showed GAERS and Wistar to be less anxious than NEC and Cm Wistar rats. CONCLUSION: To summarize, comorbid anxiety may not be present in male GAERS rats. This study also highlighted the importance of including a control Wistar group bred under the same conditions when evaluating their behavior, as using Wistar rats from commercial breeders can lead to misleading results.

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OBJECTIVES: Clinical trials for typical absence seizures are notoriously difficult, because those seizures are clinically subtle and brief, so that seizure counts by caregivers are inaccurate. As a result, treatment options are limited. Currently, there are no published studies on the use of CBD in typical absence seizures. This pilot study aims to evaluate the efficacy of pharmaceutical grade CBD in typical absence seizures. METHODS: We prospectively enrolled 14 patients aged 6 years and older, diagnosed with typical absence seizures. A baseline 24-hour ambulatory EEG was conducted, followed by a second 24-hour EEG after 90 days of treatment. The outcome was an objective measure of spike-wave complexes (SWC) burden change from pre- to post- treatment. RESULTS: After taking CBD for 90 days, 9 (64.3%) patients had an increase in SWC (ranging from 8% to 2876.5%) and 5 (35.7%) had a decrease in SWC (ranging from 62.3% to 98.9%). Of the 5 patients who had a decrease, 3 (60%) were on concomitant ethosuximide (with or without other ASMs). All 3 patients on CBD and ethosuximide improved. CONCLUSIONS: Although based on a small subset of patients, our results suggest that CBD may not be effective for typical absence seizures. However, patients on concomitant ethosuximide or on CBD monotherapy were more likely to improve.

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Episodic Ataxia Type 2 (EA2) is a rare neurological disorder caused by a mutation in the CACNA1A gene, encoding the P/Q-type voltage-gated Ca2+ channel important for neurotransmitter release. Patients with this channelopathy exhibit both cerebellar and cerebral pathologies, suggesting the condition affects both regions. The tottering (tg/tg) mouse is the most commonly used EA2 model due to an orthologous mutation in the cacna1a gene. The tg/tg mouse has three prominent behavioral phenotypes: a dramatic episodic dystonia; absence seizures with generalized spike and wave discharges (GSWDs); and mild ataxia. We previously observed a novel brain state, transient low-frequency oscillations (LFOs) in the cerebellum and cerebral cortex under anesthesia. In this study, we examine the relationships among the dystonic attack, GSWDs, and LFOs in the cerebral cortex. Previous studies characterized LFOs in the motor cortex of anesthetized tg/tg mice using flavoprotein autofluorescence imaging testing the hypothesis that LFOs provide a mechanism for the paroxysmal dystonia. We sought to obtain a more direct understanding of motor cortex (M1) activity during the dystonic episodes. Using two-photon Ca2+ imaging to investigate neuronal activity in M1 before, during, and after the dystonic attack, we show that there is not a significant change in the activity of M1 neurons from baseline through the attack. We also conducted simultaneous, multi-electrode recordings to further understand how M1 cellular activity and local field potentials change throughout the progression of the dystonic attack. Neither putative pyramidal nor inhibitory interneuron firing rate changed during the dystonic attack. However, we did observe a near complete loss of GSWDs during the dystonic attack in M1. Finally, using spike triggered averaging to align simultaneously recorded limb kinematics to the peak Ca2+ response, and vice versa, revealed a reduction in the spike triggered average during the dystonic episodes. Both the loss of GSWDs and the reduction in the coupling suggest that, during the dystonic attack, M1 is effectively decoupled from other structures. Overall, these results indicate that the attack is not initiated or controlled in M1, but elsewhere in the motor circuitry. The findings also highlight that LFOs, GSWDs, and dystonic attacks represent three brain states in tg/tg mice.

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Resumen Las epilepsias generalizadas idiopáticas (EGI) son un grupo de epilepsias generalizadas edad de pendientes, subgrupo de las Epilepsias genéticas generalizadas(EGG), con hallazgos electro-clínicos característicos y herencia poligénica. Las EGI inclu yen las cuatro epilepsias generalizadas clásicas más comunes de las EGG: la epilepsia de ausencias de la infancia (EAI), epilepsia de ausencias juveniles (EAJ), epilepsia mioclónica juvenil (EMJ) y la epilepsia con crisis tónico clónicas generalizadas. Clínicamente caracterizadas por la presencia de una o una com binación de crisis de ausencias, mioclonías, tónica-clónicas omioclónica-tónica-clónicas con patrón elec troencefalográfico de punta onda lenta de 2.5 a 6cps y activación con la hiperventilación y fotoestimula ción, Sobresalen de las EGG por compartir atributos particulares como el buen pronóstico con control frecuente de las crisis, la no evolución a encefalopa tías epilépticas, frecuente superposición clínica entre las tres primeras, pudiendo evolucionar entre ellas; la probabilidad y edad de remisión varía en cada una.Más del 80% se controlan adecuadamente con medicamentos anticrisis de amplio espectro como el ácido valproico y pueden empeorar con bloqueadores de sodio o gabaérgicos. Si bien los pacientes son previamente sanos con neurodesarrollo normal, frecuentemente se asocian con trastornos del ánimo, déficit de atención e hiperactividad (TDAH) y problemas del aprendizaje pero no presentan déficit cognitivo. El reconocimiento de este grupo de EGI es importan te para el uso adecuado del recurso, evitando estudios innecesarios, adecuada orientación del pronóstico y un tratamiento óptimo.

Abstract Idiopathic generalized epilepsies (IGE) is a group of epilepsies age-dependent, a subgroup of EGG genetic generalized epilepsies, with electro-clinical features and polygenic inheritance. Four syndromes comprising the IGEs: childhood absence epilepsy (CAD), juvenile absence epilepsy (JAE), juvenile myoclonic epilepsy (JME), and generalized tonic-clonic seizures epilepsy. Clinically characterized by the presence of one or a combination of absence seizures, myoclonus, tonic-clonic, or myoclonic-tonic-clonic with common electroencephalographic pat terns of 2.5-5.5 Hz generalized spike-wave and activated by hyperventilation or photic stimulation. They generally have a good prognosis for seizure control, not evolve to an epileptic encephalopathy. Frequent clinical overlap between the first three, being able to evolve between them; the probability and age of remission varies in each one. About 80% responding to broad-spectrum anti-seizure drugs such as valproic acid, may worsen with sodium or GABAergic blockers. Development is typically normal; however, they are frequently associated with mood disorders, attention-deficit/hyperactivity disorder (ADHD), and learning dis abilities, but do not have cognitive deficits. The recognition of this group of EGI is important for the adequate use of the resources, avoiding unnecessary studies, adequate orientation of the prognosis and an optimal treatment.

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BACKGROUND: Typical absence seizures (TAS) are seen in idiopathic generalized epilepsy. Electroencephalography (EEG) contributes to syndrome characterization and counseling in an area where genetics does not currently play a significant role. Prominent interictal EEG findings are seen in juvenile absence epilepsy (JAE) and are thus thought to be associated with less favorable outcome in any TAS case despite lack of evidence. Our study evaluates EEG findings and their association with seizure outcomes in children with TAS. METHODS: Retrospective cohort study of 123 children over 10 years with extensive EEG analysis and medical record review. Phone interviews ascertained longer-term outcomes. EEG reviewers were unaware of outcomes. RESULTS: Total cohort included 123 children with phone review completed in 98. Median follow-up was 5 years 9 months. Seizure freedom was seen in 59% off antiseizure medicines (ASMs). Interictal findings included focal discharges in 29%, fragments of spike-wave (SW) discharges in 82.1%, and generalized interictal discharges in 63.4%. Interictal SW was more likely in those who slept (100%, 18 of 18) versus those who did not (57%, 60 of 105) (P < 0.001). Outcome analysis found no associations between focal or generalized interictal findings and seizure freedom, relapse off ASM, occurrence of other seizure types, or response to first ASM. CONCLUSION: Focal and generalized interictal EEG discharges are common in children with TAS and are not associated with poorer outcomes. These interictal findings were traditionally associated with JAE rather than childhood absence epilepsy and were thus believed to be associated with potentially poorer outcome, which is probably not the case.

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Idiopathic generalized epilepsies (IGE) is a group of epilepsies age-dependent, a subgroup of EGG genetic generalized epilepsies, with electro-clinical features and polygenic inheritance. Four syndromes comprising the IGEs: childhood absence epilepsy (CAD), juvenile absence epilepsy (JAE), juvenile myoclonic epilepsy (JME), and generalized tonic-clonic seizures epilepsy. Clinically characterized by the presence of one or a combination of absence seizures, myoclonus, tonic-clonic, or myoclonictonic- clonic with common electroencephalographic patterns of 2.5-5.5 Hz generalized spike-wave and activated by hyperventilation or photic stimulation. They generally have a good prognosis for seizure control, not evolve to an epileptic encephalopathy. Frequent clinical overlap between the first three, being able to evolve between them; the probability and age of remission varies in each one. About 80% responding to broad-spectrum anti-seizure drugs such as valproic acid, may worsen with sodium or GABAergic blockers. Development is typically normal; however, they are frequently associated with mood disorders, attentiondeficit/ hyperactivity disorder (ADHD), and learning disabilities, but do not have cognitive deficits. The recognition of this group of EGI is important for the adequate use of the resources, avoiding unnecessary studies, adequate orientation of the prognosis and an optimal treatment.

Las epilepsias generalizadas idiopáticas (EGI) son un grupo de epilepsias generalizadas edad dependientes, subgrupo de las Epilepsias genéticas generalizadas(EGG), con hallazgos electro-clínicos característicos y herencia poligénica. Las EGI incluyen las cuatro epilepsias generalizadas clásicas más comunes de las EGG: la epilepsia de ausencias de la infancia (EAI), epilepsia de ausencias juveniles (EAJ), epilepsia mioclónica juvenil (EMJ) y la epilepsia con crisis tónico clónicas generalizadas. Clínicamente caracterizadas por la presencia de una o una combinación de crisis de ausencias, mioclonías, tónicaclónicas omioclónica-tónica-clónicas con patrón electroencefalográfico de punta onda lenta de 2.5 a 6cps y activación con la hiperventilación y fotoestimulación, Sobresalen de las EGG por compartir atributos particulares como el buen pronóstico con control frecuente de las crisis, la no evolución a encefalopatías epilépticas, frecuente superposición clínica entre las tres primeras, pudiendo evolucionar entre ellas; la probabilidad y edad de remisión varía en cada una. Más del 80% se controlan adecuadamente con medicamentos anticrisis de amplio espectro como el ácido valproico y pueden empeorar con bloqueadores de sodio o gabaérgicos. Si bien los pacientes son previamente sanos con neurodesarrollo normal, frecuentemente se asocian con trastornos del ánimo, déficit de atención e hiperactividad (TDAH) y problemas del aprendizaje pero no presentan déficit cognitivo. El reconocimiento de este grupo de EGI es importante para el uso adecuado del recurso, evitando estudios innecesarios, adecuada orientación del pronóstico y un tratamiento óptimo.

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Typical absence seizures (ASs) are brief periods of lack of consciousness, associated with 2.5-4 Hz spike-wave discharges (SWDs) in the EEG, which are highly prevalent in children and teenagers. The majority of probands in these young epileptic cohorts show neuropsychological comorbidities, including cognitive, memory and mood impairments, even after the seizures are pharmacologically controlled. Similar cognition and memory deficits have been reported in different, but not all, genetic animal models of ASs. However, since these impairments are subtle and highly task-specific their presence may be confounded by an anxiety-like phenotype and no study has tested anxiety and memory in the same animals. Moreover, the majority of studies used non-epileptic inbred animals as the only control strain and this may have contributed to a misinterpretation of these behavioural results. To overcome these issues, here we used a battery of behavioural tests to compare anxiety and memory in the same animals from the well-established inbred model of Genetic Absence Epilepsy Rats from Strasbourg (GAERS), their inbred strain of Non-Epileptic Control (NEC) strain (that lack ASs) and normal outbred Wistar rats. We found that GAERS do not exhibit increased anxiety-like behavior and neophobia compared to both NEC and Wistar rats. In contrast, GAERS show decreased spontaneous alternation, spatial working memory and cross-modal object recognition compared to both NEC and Wistar rats. Furthermore, GAERS preferentially used egocentric strategies to perform spatial memory tasks. In summary, these results provide solid evidence of memory deficits in GAERS rats that do not depend on an anxiety or neophobic phenotype. Moreover, the presence of differences between NEC and Wistar rats stresses the need of using both outbred and inbred control rats in behavioural studies involving genetic models of ASs.

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BACKGROUND: Significant knowledge gap exists on vagus nerve stimulation (VNS) efficacy and tolerability in medically refractory absence seizures (MRAS). This retrospective review of patients with MRAS aims to narrow this knowledge gap by comparing ultra rapid duty cycling ([URDC] ON time seven seconds, OFF time 0.2 minutes) with less frequent stimulations of rapid duty cycling (RDC, OFF time <1.1 minutes) and normal duty cycling (NDC, OFF time ≥1.1 minutes). METHODS: Patients with MRAS aged less than 21 years who underwent VNS implantation were identified. Patient demographics, antiepileptic medications, seizure types, frequency, VNS parameters, outcomes of seizure reduction rate (SRR), and seizure freedom were extracted and compared among NDC, RDC, and URDC patient cohorts. RESULTS: Thirty-six patients with MRAS were identified. After a mean follow-up of 32.6 months, responder rate ([RR], SRR ≥50%) for URDC was 80% for absence seizures and 80% for all seizure types versus 66.67% and 66.77% for NDC and 78.57% and 57.14% for RDC, respectively. Six of 10 patients (60%) on URDC achieved complete seizure freedom. A higher rate of subjective improvement in academic performance, attention, and developmental gain was noted in the URDC group. Patients on URDC tolerated higher output current (mean 3.025 mA) with minimal side effects but required a battery change sooner. CONCLUSIONS: VNS is a safe and effective nonpharmacologic management choice in patients with MRAS. The data presented demonstrate that the combination of URDC and high output current provides better RR and seizure freedom. Apart from a reduced battery life, this parameter modality seems to be well-tolerated.

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Jeavons syndrome is a common, often misdiagnosed or overlooked epileptic syndrome presenting with a triad of eyelid myoclonia with or without absence seizures, eye closure-induced EEG paroxysms, and photosensitivity. We present a seven-year-old female who presented with eyelid myoclonia evident since birth with absence seizures and migraines with associated photosensitivity. An EEG with photic stimulation confirmed the diagnosis of Jeavons syndrome. Genetic testing showed a heterozygous mutation in the PLCB1 gene which has been linked to early onset epilepsies and encephalopathic epilepsies. This mutation and her clinical presentation identifies another etiology of Jeavons syndrome and confirms it can begin from birth. Its presence highlights the importance of genetic testing in epileptic patients to better understand the links between genetics and epilepsy syndromes so appropriate treatment can be initiated.

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De novo mutations in GNB1, encoding the Gß1 subunit of G proteins, cause a neurodevelopmental disorder with global developmental delay and epilepsy, GNB1 encephalopathy. Here, we show that mice carrying a pathogenic mutation, K78R, recapitulate aspects of the disorder, including developmental delay and generalized seizures. Cultured mutant cortical neurons also display aberrant bursting activity on multi-electrode arrays. Strikingly, the antiepileptic drug ethosuximide (ETX) restores normal neuronal network behavior in vitro and suppresses spike-and-wave discharges (SWD) in vivo. ETX is a known blocker of T-type voltage-gated Ca2+ channels and G protein-coupled potassium (GIRK) channels. Accordingly, we present evidence that K78R results in a gain-of-function (GoF) effect by increasing the activation of GIRK channels in cultured neurons and a heterologous model (Xenopus oocytes)-an effect we show can be potently inhibited by ETX. This work implicates a GoF mechanism for GIRK channels in epilepsy, identifies a new mechanism of action for ETX in preventing seizures, and establishes this mouse model as a pre-clinical tool for translational research with predicative value for GNB1 encephalopathy.