Epilepsy & Behavior

BackgroundAttributional bias, a tendency to overinterpret others intentions as hostile (rather than situational or accidental), represents a component of social cognition and may affect everyday functioning. Neural models link attributional processing to fronto-temporal circuits and the default mode network, which are frequently altered in epilepsy. Difficulties in social participation and employment are common in people with epilepsy, and maladaptive attributional styles may contribute to these challenges. Attributional bias has not been systematically compared across epilepsy syndromes. MethodsWe examined attributional bias in 96 participants comprising 26 individuals with genetic generalised epilepsy (GGE), 27 with temporal lobe epilepsy (TLE), and 43 healthy controls (HC). Attributional style was assessed using the Ambiguous Intentions Hostility Questionnaire. Depressive symptoms were evaluated using the Neurological Disorders Depression Inventory in Epilepsy. Group differences were analysed, and potential clinical and demographical correlates were explored. ResultsThe GGE group exhibited higher hostility bias scores than HC (95% CI: 0.12-0.38, adjusted p = 0.014), whereas the difference between TLE and HC groups was moderate and not statistically significant (95% CI: 0.12-0.58, adjusted p = 0.059). Higher blame scores were positively associated with depressive symptoms (p = 0.016). Disease duration, seizure frequency, and antiseizure medication were not significantly associated with attributional bias. ConclusionsThese findings suggest that some individuals with genetic generalised epilepsy are more likely to interpret ambiguous situations as hostile. Altered attributional style may represent an under-recognised factor contributing to social difficulties in people with epilepsy and warrants further investigation as a potential target for psychosocial interventions. HighlightsO_LISome people with epilepsy are more prone to interpret social situations as hostile. C_LIO_LIHigher depression scores correlate with a tendency to blame external factors for misfortunes. C_LIO_LIDisease duration, antiseizure medication, and seizure frequency do not seem to influence the attributional bias. C_LI

Background and PurposeWhile the idiopathic generalized epilepsy (IGE) comprise around one fifth of all epilepsy, the pathogenesis of it is largely unknown. Previous studies identified cognitive deficits in IGE patients, nevertheless, whether (and how) the brain structure and functional connectivity (FC) reflect these deficits remains underexplored. Here, we aim to find structural and FC differences in cognitively impaired IGE patients. Materials and MethodsWe recruited 36 IGE patients and 49 matched healthy controls (HC) in this cross-sectional study. All participants underwent structural and resting-state fMRI (rs-fMRI) scanning with a 3 Tesla MRI. Voxel-based morphometric analysis (VBM) was used to assessed structure differences, and seed-based analysis of rs-fMRI was used to examine FC. We examined the cognitive performance of patient with MoCA (Montreal Cognitive Assessment), grouped them into high (HMoCA, >25) and low (LMoCA, [&le;]25) group, and further examined the brain structural changes functional changes in each group. ResultsIGE patients showed right significant decrease in cerebellar gray matter volume (GMV), negatively correlating with the disease duration (r=-0.542, p=0.001), and increase in the left dorsolateral superior frontal gyrus GMV. Right cerebellum showed increased connectivity to the precuneus and angular gyrus, decreased connectivity to the postcentral gyrus and Rolandic operculum. Surprisingly, we found that LMoCA IGE patients (with more cognitive deficits) had increased right nucleus accumbens (NAc) GMV (t = -4.413, p < 0.001) and FC and a stronger NAc - prefrontal cortex FC (t = -2.683, p = 0.013), in comparison with the patients with high MoCA. ConclusionsCognitive impairment in IGE patients is linked to the NAc structural changes and NAc-prefrontal circuit alterations. These results provide novel circuit-level insights into understanding the cognitive impairment in IGE patients, contributing to revealing the pathophysiological mechanisms of IGE.

Sudden unexpected death in Epilepsy (SUDEP) is the leading cause of death in patients with Epilepsy. Although SUDEP results from cardiorespiratory arrest, its underlying mechanisms are poorly understood. Considering the significant association between stress-related disorders and Epilepsy, we hypothesized that stress exaggerates autonomic reflexes critical in cardiorespiratory function and that these exaggerated reflexes increase susceptibility to SUDEP. Experiments were performed using a novel mouse model of SUDEP where chronic hyperactivity of central corticotropin-releasing hormone (CRH) neurons (Kcc2/Crh) predisposes mice to SUDEP in the weeks following seizure induction based on the ventral intrahippocampal kainate (vIHKA) model of chronic Epilepsy. In our study, the vIHKA model was employed in both wild-type (WT) and Kcc2/Crh mice while they were monitored with EEG and ECG using in vivo telemetry and underwent terminal autonomic reflex testing at time points when mortality peaked and plateaued. A resting tachycardia developed by one week following vIHKA injection but subsided by day 30 in both WT and Kcc2/Crh mice. During spontaneous seizures, Kcc2/Crh mice had more pronounced reflex-like ictal bradycardias compared to WT controls that notably occurred prior ([~]10 sec) to seizure termination. vIHKA injection promoted time-dependent exaggeration of autonomic reflexes, with Kcc2/Crh mice exhibiting robust autonomic disturbances compared to WT controls, including a pronounced serotonin-mediated Bezold Jarisch reflex. Taken together, our findings indicate that increased autonomic disturbance burden parallels time-dependent SUDEP susceptibility in mice with hyperactive stress circuits.

Objective: The postictal state is a major yet underrecognised component of epilepsy burden. We aimed to develop a structured patient-reported instrument to quantify postictal recovery, characterise its multidimensional burden and identify demographic, clinical, psychiatric and treatment-related factors associated with postictal severity and duration. Methods: We conducted a prospective, single-centre observational cohort study (Timone Hospital, Marseille, February 2025 - March 2026). Consecutive patients aged >=15 years admitted for scalp or stereo-EEG video-monitoring were included. Patients completed the Postictal Recovery Scale (PRS), an 11-domain questionnaire assessing fatigue, mood, sensory, motor, language, orientation, time perception and postictal amnesia. Items were rated from 0 (severe impairment) to 3 (no symptoms), yielding a total score of 0-33. Internal consistency was assessed using Cronbach alpha. Associations between PRS scores, subjective postictal duration and covariates were analysed using group comparisons, correlations and regression models. Results: Of 107 enrolled patients, 96 were included. PRS showed good internal consistency (Cronbach alpha; = 0.79). 96% of patients reported experiencing postictal symptoms, with fatigue (80%) and postictal amnesia (79%) being the most frequent and severe manifestations. Recovery exceeded one hour in 21% of patients. Greater postictal impairment was associated with higher interictal anxiety (Spearman {rho} = -0.32, p = 0.0018) and depressive symptoms (Spearman {rho} = -0.40, p = 0.0001), whereas demographic, epilepsy-related and treatment variables showed no significant associations. Altered postictal time perception was reported by 40% of patients and was associated with disorientation, but not psychiatric symptoms. Subjective postictal duration was longer than subjective ictal duration (Wilcoxon test, p < 0.0001). Significance: The postictal state is a frequent and multidimensional patient-reported experience. Greater postictal severity, particularly concerning anxiety and depression, is associated with interictal psychiatric comorbidity, while altered temporal experience emerges as a distinct dimension of postictal dysfunction. These findings support integrating postictal measures into clinical practice and trials.

BackgroundDistinguishing epilepsy from functional/dissociative seizures (FDS) is an ongoing diagnostic challenge. Misdiagnosis delays appropriate treatment and puts patients at significant risk. Quantitative analyses of clinical EEG offer a potential avenue for developing decision-support tools in the diagnosis of seizure disorders. Recent work using univariate features demonstrated that reliably identifying diagnostic traits in the presence of confounding factors remains challenging. However, diagnostic information might be available in multivariate features such as network-based measures. Using a well-controlled dataset, we run the first diagnostic accuracy study assessing the potential of multivariate resting-state EEG markers to directly discriminate between a diagnosis of epilepsy and one of FDS at the time when a diagnosis is suspected and prior to treatment initiation. MethodsThe dataset, previously examined in a published study, includes 148 age- and sex-matched individuals with suspected seizure disorders who were later diagnosed with non-lesional epilepsy (n=75) or FDS (n=73). Eyes-closed, resting-state EEG data used for the analyses were normal on visual inspection, and acquired while participants were medication-free. Functional network measures in the 6-9 Hz range were extracted and machine learning implemented to assess their predictive potential; different model configurations (including varying model types, dimensionality reduction methods, and approaches to enhance feature stability) were tested to identify the most promising approach for future translational implementations. ResultsNetwork measures derived from resting-state EEG discriminate between conditions at levels significantly above chance (maximum balanced accuracy: 67.5%). Their sensitivity to epilepsy (81.8%) is consistently higher than their sensitivity to FDS (53.3%). A systematic assessment of model choices indicates that improving the temporal stability of network features through epoch-wise averaging improves classification accuracy (62.6% to 67.5%). Multiple nonlinear model types succeed on the classification problem, with the three-best performing assigning a consistent diagnostic label to 77.5% of the individuals; however, model choice remains a strong determinant of overall classification accuracy. Dimensionality reduction did not provide a significant advantage in our models. ConclusionWe establish evidence for the clinical validity of selected network-based markers to discriminate between a diagnosis of non-lesional epilepsy and FDS prior to treatment initiation, highlighting the measures potential to support post-test probability estimation in the clinic. Our models, configured to optimise balanced accuracy, classified people with epilepsy more accurately than people with FDS, indicating that these measures are specific to epilepsy and should not be interpreted as markers of a positive diagnosis of FDS.

Temporal lobe epilepsy (TLE) is a heterogeneous disorder with most clinical presentations involving unilateral or bilateral hippocampal seizure onsets. Antiseizure medications are often ineffective for TLE, and epilepsy surgery can have variable outcomes. Risk factors for TLE are readily identifiable and typically precede chronic epilepsy, providing a window of opportunity for preventative treatments. However, there are currently no clinically approved anti-epileptogenic therapies. In this study, we investigate the role of Wnt signaling in epileptogenesis using two mouse TLE models, the intrahippocampal kainate model of unilateral TLE (IHK), and the intraperitoneal kainate model of bilateral TLE (IPK). We specifically examined adult-born immature dentate granule cells as these cells have been heavily implicated in the pathogenesis of TLE and clinical TLE is typically initiated in adulthood. We observed that adult-born immature dentate granule cells undergo pathological morphological changes during epileptogenesis in both the IHK and IPK models of TLE. When compared across epileptogenic zones, however, these changes differed between the two models. Wnt signaling also decreased in these cells in epileptic mice during the epileptogenic period. When mice were treated with SB415286, a highly selective Wnt activator, Wnt signaling in immature dentate granule cells was restored to baseline levels and pathological remodeling changes were reduced in both models. These data therefore suggest that a reduction in Wnt signaling in immature dentate granule cells plays an etiological role in epileptogenesis, and that restoring Wnt signaling using Wnt activating drugs or alternative agents may have therapeutic potential as an anti-epileptogenic strategy in TLE.

Objective Memory impairment is a frequent comorbidity of focal epilepsy, incompletely explained by seizure frequency or structural pathology. Ictal and postictal hippocampal dysfunction disrupt memory processes, but their cumulative impact remains poorly quantified. This study introduces cumulative hippocampal seizure-related burden metrics and examines their association with long-term memory consolidation. Methods Twenty consecutive patients undergoing stereo-EEG in Marseille (2016-2018) were prospectively included. Continuous stereo-EEG recordings between two memory assessments (30 minutes and one week post-encoding) were analysed. Hippocampal ictal involvement and durations were assessed using epileptogenicity markers and visual stereo-EEG analysis. The postictal period was quantified using permutation entropy. Cumulative hippocampal seizure-related burden metrics (ictal, postictal and combined: c-HipSZB) were computed across hippocampus-involving ictal events. Verbal and visual memory were assessed using standardized recall and recognition tasks. Associations were examined using univariate and multivariate analyses. Results Higher dominant-hemisphere hippocampal burden was associated with poorer one-week verbal memory (performance and retention), independently of most covariates. Higher c-HipSZB was associated with lower total recall performance (RT; free + cued) and RT retention ({beta} = -25.04 and -23.88; R2 = 0.57 and 0.53; p < 0.05) and accounted for the greatest variance in both outcomes (adjusted R2= 0.59 and 0.53; {beta} = -25.45 and -24.27; p < 0.01), particularly when adjusting for epilepsy duration. No robust associations were observed between non-dominant-hemisphere hippocampal seizure-related burden metrics and visual memory. Effects predominantly involved recall. Interpretation Cumulative ictal-postictal hippocampal dysfunction is a major determinant of impaired long-term verbal memory consolidation in focal epilepsy.

ObjectiveSeizure dogs are service animals trained to respond supportively to seizures in people with epilepsy; some are also trained to detect seizure-specific scents, particularly ictal volatile organic compounds (VOCs). This survey study examines feasibility and safety of incorporating a seizure service dog (SSD) into an inpatient setting, as well as patient perceptions of having an SSD in the Epilepsy Monitoring Unit (EMU). MethodsOur SSD underwent specialized training for seizure response and seizure recognition based on seizure-specific VOCs, and accompanied his epileptologist owner in the EMU on rounds for over four years prior to the study. We administered surveys to patients hospitalized in the EMU before and after interactions with a trained seizure dog. The surveys assessed the patients comfort with the dog, perceived usefulness of service dogs, safety, and tolerability. Select case examples are also presented in which seizure dog spontaneously alerted prior to epileptic seizures; seizures later confirmed by independent EEG review. ResultsPatient responses underscored overall high enthusiasm for seizure dog therapy, with 93% of participants reporting feeling "very comfortable" or "extremely comfortable" with a seizure dog present. No adverse concerns or negative experiences were reported by participants. 91% reported personally experiencing benefits of working with the seizure dog, citing emotional and comfort benefits during their hospitalization. 94% of participants were comfortable with physical contact with the dog or had no proximity preference. ConclusionThese findings suggest that seizure service dogs can be safely integrated into the inpatient EMU setting and have potential to enhance patient care and emotional well-being during EMU monitoring. Summary PointsO_LITotal of 98 patients admitted to EMU were surveyed about opinions regarding seizure dogs and comfort with integration of seizure dog in EMU setting, with 35 patients completing post-test surveys after interacting with the seizure dog. C_LIO_LI93% of surveyed EMU patients completing post-test surveys felt very or extremely comfortable with the seizure dog; no negative experiences or safety concerns were reported. C_LIO_LI91% reported personally experiencing emotional benefits of working with the seizure dog. C_LIO_LISelect case examples demonstrate that the trained seizure dog in our study may be able to spontaneously identify epileptic seizures. C_LI

1.PurposeSYNGAP1-related developmental and epileptic encephalopathy (SYNGAP1-DEE) is characterized by high rates of both epilepsy and autism spectrum disorder (ASD). While the clinical spectrum is well-documented, the link between specific seizure semiologies and caregiver-reported autistic behaviors is not well understood. This study analyzed the correlation between ten distinct seizure types, their frequencies, and a caregiver-reported autistic behavior score. MethodClinical data were extracted from the PATRE (PATient-based phenotyping and evaluation of therapy for Rare Epilepsies) Registry for SYNGAP1, in the framework of the EURAS project (Grant No. 101080580, Horizon Europe). This study employed a retrospective cross-sectional analysis of caregiver-reported registry data. Analysis was restricted to an analytic cohort of N=337 participants with complete data for both the epilepsy questionnaire (including epilepsy status, seizure semiology, and peak seizure frequency items) and the behavior questionnaire (from a total N=522 registry participants). Caregiver-reported autistic behaviors were quantified using a standardized caregiver-reported scale (Likert 1-5). Statistical associations were evaluated using the Wilcoxon rank-sum test to compare caregiver-reported autistic behavior scores across different seizure semiologies and Spearmans rank correlation to assess the impact of seizure frequency (9-point scale). ResultsWithin the analytic cohort (N=337), epilepsy was reported in 259 patients. Eyelid myoclonia was the most prevalent semiology, affecting 64.9% (n=168) of the epilepsy-positive group. Atypical absences (n=77) demonstrated the most profound and statistically robust association with higher caregiver-reported autistic behavior scores (FDR-adjusted p = 0.001). Significant associations were also observed for typical absences (n=70, FDR-adjusted p = 0.018), eyelid myoclonia (FDR-adjusted p = 0.018), myoclonic-atonic seizures (n=40, FDR-adjusted p = 0.019), and atonic seizures (n=72, FDR-adjusted p = 0.025). Focal and tonic-clonic seizures showed weaker associations (FDR-adjusted p = 0.026 and p = 0.047, respectively). Crucially, quantitative analysis revealed no significant correlation between ordinal caregiver-reported peak seizure frequency ratings and caregiver-reported autistic behavior scores across all semiologies (e.g., Eyelid Myoclonia: p=0.096; Atypical Absences: p=0.744), indicating no detectable association between peak-frequency ratings and caregiver-reported autistic behavior scores. ConclusionHigher caregiver-reported autistic behavior scores in SYNGAP1-DEE were most strongly associated with the presence of atypical absences, representing a generalized, thalamocortical seizure network dysfunction. In contrast, no detectable association was observed between caregiver-reported autistic behavior scores and the ordinal caregiver-reported peak seizure frequency metric. Atypical absences and related semiologies may serve as clinical "red flags" for increased neurodevelopmental comorbidity severity, regardless of reported peak seizure frequency. Abstract SummaryThis study investigates the relationship between ten seizure semiologies, seizure frequency, and severity of caregiver-reported autistic behaviors in a large-scale international cohort of N=337 patients with SYNGAP1-DEE. We identify a robust association between elevated caregiverreported autistic behavior scores and specific thalamocortical seizure patterns, most prominently atypical absences. Notably, our analysis reveals that this association is independent of seizure frequency, demonstrating no detectable association between this ordinal, caregiver-reported seizure frequency metric and caregiver-reported autistic behaviors.

Stress is a commonly reported seizure precipitant and may contribute to the development of psychiatric comorbidities in epilepsy, yet how chronic stress interacts with epileptic circuits remains poorly understood. We investigated the impact of chronic restraint stress on physiological, behavioral, and synaptic outcomes in a mouse model of Dravet syndrome, specifically corticotropin-releasing factor (CRF) neurons in the bed nucleus of the stria terminalis (BNST), a stress-responsive region implicated in epilepsy patients. Chronic restraint stress produced divergent hypothalamic-pituitary-adrenal axis responses, with stressed Dravet syndrome mice exhibiting elevated corticosterone, increased mortality in females, and increased locomotion and anxiety-like behavior. Ex vivo electrophysiological recordings revealed that chronic stress increased spontaneous excitatory event frequency onto BNST CRF neurons in both genotypes and selectively increased sEPSC and sIPSC amplitude in Dravet syndrome mice. Evoked recordings demonstrated genotype-specific effects of stress on glutamatergic transmission in CRF neurons of the DS group. This suggests greater stress-dependent remodeling of spontaneous and evoked synaptic activity in DS. These findings suggest chronic stress may worsen physiological and behavioral outcomes in Dravet syndrome and promote specific maladaptive alterations in BNST CRF circuitry. More broadly, these results suggest that stress interacts with seizure vulnerability and potentially contributes to neuropsychiatric comorbidities and epilepsy.

Mutations in DOCK7 have been identified in individuals with epileptic encephalopathies. Given that epileptic encephalopathies are a set of disorders that result in seizure activity and associated cognitive and behavioral impairments, we investigated the role of Dock7 in seizure susceptibility and flurothyl kindling using the repeated flurothyl seizure model in mice. Male and female Dock7+/+ and Dock7{bigtriangleup}ex3-4/{bigtriangleup}ex3-4 mice were subjected to 8 daily flurothyl exposures (kindling, induction phase) followed by a 28-day incubation period and a subsequent flurothyl rechallenge (retest). No significant differences were observed in baseline myoclonic jerk or generalized seizure thresholds between genotypes or sexes. However, over the kindling period, male Dock7{bigtriangleup}ex3-4/{bigtriangleup}ex3-4 mice exhibited slightly higher myoclonic jerk and generalized seizure thresholds compared to Dock7+/+ males across trials. Female mice showed similar trends, but the differences were only significant for generalized seizure thresholds. Following the 28-day incubation period and flurothyl retest, male mice of both genotypes maintained their seizure thresholds upon retest. Dock7+/+ female mice showed increased myoclonic jerk and generalized seizure thresholds during retest, while Dock7{bigtriangleup}ex3-4/{bigtriangleup}ex3-4 females maintained their thresholds. A key finding was the emergence of more severe forebrain[-&gt;]brainstem seizures upon flurothyl retest in a significant percentage of mice across all groups. However, the proportion of mice developing these seizures did not differ significantly between genotypes. Although DOCK7 mutations have been linked to human epileptic encephalopathies and neurodevelopmental dysfunction, we find that Dock7{bigtriangleup}ex3-4/{bigtriangleup}ex3-4 male and female mice do not show heightened excitability or seizure susceptibilities using the repeated flurothyl seizure model. HighlightsO_LIDock7{bigtriangleup}ex3-4/{bigtriangleup}ex3-4 mice show slightly higher seizure thresholds during flurothyl kindling C_LIO_LIDock7{bigtriangleup}ex3-4/{bigtriangleup}ex3-4 mice do not exhibit heightened seizure susceptibility upon retest. C_LIO_LIForebrain-brainstem seizures emerged upon retest regardless of Dock7 genotype. C_LI

AIM: STXBP1-related disorder (STXBP1-RD) is a severe developmental and epileptic encephalopathy characterized by early-onset seizures and persistent cognitive and motor impairments. With disease-modifying trials emerging, a disorder-specific severity scale is needed. To address this, we adapted a validated clinician-reported measure from CDKL5 Deficiency Disorder to develop the STXBP1 Clinical Severity Assessment (S-CSA) and evaluated its psychometric properties. METHOD: The S-CSA was adapted from the CDKL5 Clinical Severity Assessment through expert consensus sessions with STXBP1 clinicians. Revisions addressed gaps in motor and vision domains, adding tremor and vision items. The measure was administered to 123 individuals with STXBP1-RD. Psychometric evaluation included confirmatory factor analysis, internal consistency, composite reliability, average variance extracted, and distinctiveness, compared with recommended thresholds. RESULTS: Analyses supported a three-domain structure (motor, communication, vision) with factor loadings >0.5 and strong internal consistency (Cronbachs alpha >0.7; composite reliability >0.88). Model fit and variance metrics met recommended standards, and domains demonstrated distinctiveness. No ceiling or floor effects were observed. Minimal skew was seen in motor (0.34) and communication (0.16) domains; positive skew in vision (2.2) was seen, identifying patients with and without cortical visual impairment. INTERPRETATION: The S-CSA demonstrates strong validity and reliability in STXBP1-RD and may show utility in clinical trials for STXBP1-RD and potentially other severe DEEs. Key Words: STXBP1-Related Disorder, Developmental and Epileptic Encephalopathies, Clinical Outcome Assessments

Genetic deletion or pharmacological blockade of P2X7 receptors (Rs) counteract status epilepticus (SE) in animal models of epilepsy. It is, however, unclear whether P2X7Rs are localized at astrocytes or neurons, and the reason for astrocytic atrophy arising in consequence of SE is also ambiguous. We conducted a combined morphological/electrophysiological study in order to investigate these issues. It has been shown that kainic acid (KA)-induced SE in mice led to the atrophy of hippocampal astrocytes and at the same time to the decrease of ezrin immunoreactivity and its co-expression with mCherry, whose synthesis has been initiated by the injection of a virus complex. mCherry expression in astrocytes enabled us to study changes in cell somata and processes brought about by KA-injection. Ezrin is a plasmalemmal-cytoskeleton linker; its grade of expression indicates changes in the existence/function of small peripheral astrocytic processes. Pretreatment of mice with the blood-brain barrier-permeable P2X7R antagonist JNJ-47965567 prevented the SE-induced damage of astrocytes. KA caused a potentiation of dibenzoyl-ATP (Bz-ATP) currents in astrocytes but not neurons of the hippocampus. This effect was also abolished by pre-treatment of mice with JNJ-47965567 before applying KA, although no similar changes occurred in hippocampal CA1 neurons. The measurement of spontaneous postsynaptic currents (sPSCs) and spontaneous excitatory postsynaptic currents (sEPSCs) indicated a presynaptic facilitation of neurotransmitter release by Bz-ATP. In conclusion, we suggest that astrocytic P2X7Rs are the primary target of ATP release from damaged CNS cells in the hippocampus which simultaneously causes damage to astrocytic somata and processes.

Purinergic 2X7 receptor (P2X7R) is considered to play a critical role in neurological diseases, including epilepsy, and has also been proposed as a potential marker for neuroinflammation. This study aimed to validate the binding properties of the novel P2X7R radiotracer, [3H]JNJ-64413739, in rat brain using in vitro autoradiography, and additionally to explore spatial and temporal changes in P2X7R binding levels in a rat model of temporal lobe epilepsy using intrahippocampal administration of kainic acid (KA). Saturation of [3H]JNJ-64413739 to brain sections yielded a KD of approximately 3 nM, with full saturation around 10 nM. The radiotracer was displaced with a structurally different P2X7R ligand, JNJ-47965567, indicating high affinity and specificity to rat P2X7R. In post epileptic rats, region-specific [3H]JNJ-64413739 binding revealed a bilateral increase in the hippocampal formation and its subregions few days after status epilepticus, peaking at day 30, and remained stable at this high level until day 90. Similar temporal profiles were identified in subcortical regions such as the thalamus. Interestingly, no change in binding was observed in the temporal and piriform cortices until day 30 where a dramatic increase occurred. Also, in the corpus callosum, significant increase was detected 30 days after the seizure. These results show that P2X7R binding, likely reflecting inflammation, is increased at delayed time points and exhibit region-specific patterns that is different from acute effects. Our findings suggest that P2X7R may contribute to sustained neuroinflammation and may be involved in those changes leading to epileptogenesis and the development of chronic epilepsy. Highlights[3H]JNJ-64413739 binds specifically to the purinergic P2X7 receptor (P2X7R) and saturates in the rat brain. P2X7R binding increases in a region- and time-dependent manner following status epilepticus. P2X7R binding remains elevated during chronic epilepsy in all examined brain regions. P2X7R is considered a link between early seizures and sustained neuroinflammation and epileptogenesis.

AbstractO_ST_ABSBackgroundC_ST_ABSInvasive neuromodulation may be used in patients if seizure medications fail and surgery is not an option. However, moderate success is achieved and improved paradigms are required. The medial septum has been considered a suitable target for the treatment of temporal lobe epilepsy due to its location and connectivity. ObjectiveTo assess the effect of medial septum low-frequency deep brain stimulation to inhibit pentylenetetrazole (PTZ)-induced seizures. MethodsMale Sprague-Dawley rats were stereotaxically implanted in the medial septum and left dorsal hippocampus one week prior to the experimental protocols. Then, the animals were assigned to three experimental groups: 1) 10 Hz + PTZ (n=3); 2) 5 Hz + PTZ (n=7); and 3) 5 Hz (n=7). The stimulation consisted of a 30 min train of biphasic square-wave pulses at a current of 150 {micro}A and a pulse duration of 1 ms. Rats were subjected to the experimental protocol every 24 h for seven consecutive days. ResultsSubjects exposed to the 10 Hz died after the first PTZ injection. The 5 Hz stimulation not only prevented the animals death, but also induced a protective effect against generalization. Surprisingly, in both 5 Hz groups, septal and hippocampal spike-wave-like discharges were detected (mainly integrated by theta oscillations). This phenomenon was correlated with the generalization avoidance. ConclusionsWhile this study is preclinical in nature, our findings underscore the potential of using low-frequency medial septum stimulation for future clinical applications. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=113 SRC="FIGDIR/small/720729v1_ufig1.gif" ALT="Figure 1"> View larger version (26K): org.highwire.dtl.DTLVardef@53482org.highwire.dtl.DTLVardef@1ba5d7corg.highwire.dtl.DTLVardef@4f999aorg.highwire.dtl.DTLVardef@1ed6744_HPS_FORMAT_FIGEXP M_FIG C_FIG

Maintaining electrical signaling homeostasis in the human neocortex relies on cell-type specific gene expression programs. However, when these programs are disrupted, the resulting imbalances can contribute to the pathogenesis of neurological disorders like epilepsy. Genetic factors are particularly implicated in a specific subtype of epilepsy known as refractory epilepsy or drug-resistant epilepsy (RE/DRE). This study shows the main results of the analysis of single cell transcriptomics for five pediatric RE patients in Colombia. A total of six samples obtained through surgical resection were analyzed by single-nuclei RNA sequencing (snRNA-seq). The genome of one patient was sequenced using high fidelity long-read sequencing. Functional enrichment of differentially expressed genes (DEGs) revealed glia-driven dysregulation of synaptic signaling, impaired glial-neuronal communication, and altered expression of genes related to neurotransmitter transport and calcium signaling. Activation of taste receptors in neurons was associated with neuroinflammatory processes. Structural variants were detected in genes associated with alterations of expression in specific cell types. This new data resource increases the diversity of information needed to develop new strategies for diagnosis of refractory epilepsy.

IntroductionTo leverage high-frequency oscillations (HFOs) as a biomarker with significant potential, this study compared a large set of detectors on a unified dataset, aiming to evaluate their clinical applicability under realistic conditions. MethodsEleven automatic detectors were applied to a retrospective dataset of intracranial and scalp EEGs from 27 consecutive pediatric patients. Inter-detector agreement was assessed using Spearmans Rho, and the area under the curve (AUC) for seizure onset zone (SOZ) prediction served as a consistent reference standard to enable reliable comparisons across recording modalities. Analyses were conducted separately for HFO and Spike-HFO detections. ResultsThe average age of our cohort was 12.4 years (SD 4.0; range 5-18). AUC values in scalp EEG ranged from 0.61 to 0.67 for HFOs and from 0.53 to 0.63 for Spike-HFO. AUC values in intracranial EEG ranged from 0.48 to 0.66 for HFOs and 0.54 to 0.69 in Spike-HFO. Although only three of the 11 detectors were specifically developed or adapted for scalp EEG, the detectors generally achieved higher AUC values and stronger agreement in scalp EEG ConclusionsWe present the first study comparing intracranial and scalp detectors by testing them beyond the modalities for which they were originally designed. Although the clinical utility of detections was comparable across EEG modalities, it remained lower than reported in original studies assessing the diagnostic value of HFOs. Caution is warranted when applying a publicly available detector to a new dataset, and detector robustness remains a critical issue. Key points- A comprehensive head-to-head comparison of 11 detectors demonstrated significant variability in detector agreement and clinical utility - Clinical utility was not necessarily linked to the EEG recording type the detector was originally designed for - Despite widely accepted use of automatic detections, detector robustness remains a critical issue

ObjectiveBrain infection is an underrecognized global cause of epilepsy due to the ensuing neuroinflammation and neurological damage. Immune system response, including underlying neuroinflammation, is dynamically shaped by the intestinal microbiome. In experimental rodent epilepsy models, seizure burden and antiseizure medication (ASM) activity can be dramatically influenced by gut dysbiosis, including in the Theilers murine encephalomyelitis virus (TMEV) infection model of acute symptomatic seizures and long-term epilepsy. We previously demonstrated that experimentally induced gut dysbiosis via repeated antibiotic administration alters seizure burden and carbamazepine (CBZ) anticonvulsant activity in this model (1). However, whether dysbiosis and CBZ differentially shape neuropathological damage and neuroinflammation following TMEV infection was not reported. MethodsHere, we extended our earlier study to quantify the extent to which antibiotic-induced gut dysbiosis and repeated CBZ administration during TMEV infection altered the severity of acute neuropathology. Hippocampal tissue was analyzed 7 days post-infection using quantitative immunofluorescence to assess neuronal death, microglial and astroglial reactivity, and neuronal proliferation across CA1, CA3, and dentate gyrus (DG) subregions. ResultsDysbiosis markedly exacerbated hippocampal neurodegeneration and gliosis, accompanied by increased glial proliferation, whereas CBZ administration reversed these effects in a hippocampal region-dependent manner. Collectively, these findings demonstrate that the gut microbiome primes hippocampal neuroimmune responses to viral infection-induced acute seizures and modifies associated neuropathology in a hippocampal region-specific manner. SignificanceThis work identifies the gut-brain axis as a critical determinant of neuroinflammatory damage after infection-induced symptomatic seizures, highlighting the gut microbiome as a potential therapeutic target to alleviate the worldwide epilepsy burden. HighlightsO_LIExperimentally-evoked gut dysbiosis exacerbates hippocampal neurodegeneration after brain viral infection. C_LIO_LIExperimentally-evoked gut dysbiosis increases microgliosis and glial proliferation after brain viral infection. C_LIO_LICarbamazepine reversed dysbiosis-induced neuroinflammation and neurodegeneration. C_LIO_LIExperimentally-evoked gut dysbiosis differentially modulates glial response in the dentate gyrus. C_LI

ObjectiveVagus nerve stimulation (VNS) is an established neuromodulation therapy used in the management of drug-resistant epilepsy (DRE), or when other intracranial surgical modalities have not reduced seizure burden. We evaluated whether prior intracranial surgery for epilepsy influences safety and effectiveness outcomes with adjunctive VNS, using real-world data from the CORE-VNS study. MethodsCORE-VNS (NCT03529045), a prospective, multicenter, international observational study, was designed to collect data on seizure and non-seizure outcomes in patients with DRE treated with VNS. Participants were identified as having or not having undergone prior intracranial brain surgery for epilepsy (ICSE) and received an initial VNS implant. Baseline seizure frequency data and patient-reported outcome measures were collected at 3, 6, 12, 24, and 36 months. This analysis compared the baseline data for VNS therapy and safety outcomes at 36 months. ResultsAmong 531 participants implanted with VNS, prior ICSE was performed in 84. Median percentage seizure reductions at 36 months for all seizures (76.6% and 76.3%), all focal seizures (83.3% and 71.8%), and all generalized seizures (77.8% and 76.2%) were found to be similar between those without and with a history of ICSE, respectively. The 50% responder rate for all seizures reported at baseline was similar, 64.8% and 61.8%, in both groups and complete seizure freedom was reported by 17.9% and 8.8%, respectively. Implant-related adverse events (AE) and serious AE rates were similar between groups. ConclusionVNS was associated with clinically meaningful seizure reductions and showed a consistent safety profile irrespective of the history of ICSE. Prior ICSE should not be a contraindication to the consideration of VNS.

Ferroptosis is a form of non-apoptotic cell death in which iron catalyzes the formation of reactive oxygen species, leading to lipid peroxidation. Experimentally, this process has recently been associated with seizures based on the increased levels of specific markers (4-hydroxynonenal and malondialdehyde) in the brain and plasma. Clinically, iron deposits have been identified in resected tissue from patients with refractory temporal lobe epilepsy. Quantitative susceptibility mapping (QSM) offers an opportunity to detect these accumulations in vivo. In this study, we investigated how pilocarpine-induced status epilepticus contributes to the generation of iron deposits in diverse cerebral regions and whether QSM can detect these deposits longitudinally. We scanned 14 animals (n=10 experimental; n=4 control) at five different time points (pre-status epilepticus induction and 1, 7, 14, 21 days post-induction) using QSM. We identified iron deposits in the caudate putamen, hippocampus, thalamus, and primary somatosensory cortex of experimental animals, which is consistent with histological findings. The initial size of the hippocampal iron deposits significantly increased over the following weeks. None of these effects was observed in the control animals. The presence of cerebral iron depositions in an animal model of pilocarpine-induced status epilepticus suggests that ferroptosis may be involved in the onset, development, and progression of spontaneous recurrent seizures. Furthermore, non-invasive, longitudinal in vivo mapping of brain iron deposits could be a potential imaging marker in neurological disorders such as epilepsy. Future experiments will be required to determine the origin of the iron and avoid its progressive accumulation. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=70 SRC="FIGDIR/small/712677v1_ufig1.gif" ALT="Figure 1"> View larger version (36K): org.highwire.dtl.DTLVardef@14abf67org.highwire.dtl.DTLVardef@5c08fborg.highwire.dtl.DTLVardef@51c40forg.highwire.dtl.DTLVardef@1eb5f9_HPS_FORMAT_FIGEXP M_FIG C_FIG