Structural basis of TRPV3 inhibition by an antagonist.

The TRPV3 channel plays vital roles in skin physiology. Dysfunction of TRPV3 causes skin diseases, including Olmsted syndrome. However, the lack of potent and selective inhibitors impedes the validation of TRPV3 as a therapeutic target. In this study, we identified Trpvicin as a potent and subtype-selective inhibitor of TRPV3. Trpvicin exhibits pharmacological potential in the inhibition of itch and hair loss in mouse models. Cryogenic electron microscopy structures of TRPV3 and the pathogenic G573S mutant complexed with Trpvicin reveal detailed ligand-binding sites, suggesting that Trpvicin inhibits the TRPV3 channel by stabilizing it in a closed state. Our G573S mutant structures demonstrate that the mutation causes a dilated pore, generating constitutive opening activity. Trpvicin accesses additional binding sites inside the central cavity of the G573S mutant to remodel the channel symmetry and block the channel. Together, our results provide mechanistic insights into the inhibition of TRPV3 by Trpvicin and support TRPV3-related drug development.

Up and Down States of Cortical Neurons in Focal Limbic Seizures.

Recent work suggests an important role for cortical-subcortical networks in seizure-related loss of consciousness. Temporal lobe seizures disrupt subcortical arousal systems, which may lead to depressed cortical function and loss of consciousness. Extracellular recordings show ictal neocortical slow waves at about 1 Hz, but it is not known whether these simply represent seizure propagation or alternatively deep sleep-like activity, which should include cortical neuronal Up and Down states. In this study, using in vivo whole-cell recordings in a rat model of focal limbic seizures, we directly examine the electrophysiological properties of cortical neurons during seizures and deep anesthesia. We found that during seizures, the membrane potential of frontal cortical secondary motor cortex layer 5 neurons fluctuates between Up and Down states, with decreased input resistance and increased firing rate in Up states when compared to Down states. Importantly, Up and Down states in seizures are not significantly different from those in deep anesthesia, in terms of membrane potential, oscillation frequency, firing rate, and input resistance. By demonstrating these fundamental similarities in cortical electrophysiology between deep anesthesia and seizures, our results support the idea that a state of decreased cortical arousal may contribute to mechanisms of loss of consciousness during seizures.

Biomimetic Synthesis of Rhytidenone†A and Mode of Action of Cytotoxic Rhytidenone†F.

The rhytidenone family comprises spirobisnaphthalene natural products isolated from the mangrove endophytic fungus Rhytidhysteron rufulum AS21B. The biomimetic synthesis of rhytidenone A was achieved by a Michael reaction/aldol/lactonization cascade in a single step from the proposed biosynthetic precursor rhytidenone F. Moreover, the mode of action of the highly cytotoxic rhytidenone F was investigated. The pulldown assay coupled with mass spectrometry analysis revealed the target protein PA28γ is covalently attached to rhytidenone F at the Cys92 residue. The interactions of rhytidenone F with PA28γ lead to the accumulation of p53, which is an essential tumor suppressor in humans. Consequently, the Fas-dependent signaling pathway is activated to initiate cellular apoptosis. These studies have identified the first small-molecule inhibitor targeting PA28γ, suggesting rhytidenone F may serve as a promising natural product lead for future anticancer drug development.

Tautomerization-dependent recognition and excision of oxidation damage in base-excision DNA repair.

NEIL1 (Nei-like 1) is a DNA repair glycosylase guarding the mammalian genome against oxidized DNA bases. As the first enzymes in the base-excision repair pathway, glycosylases must recognize the cognate substrates and catalyze their excision. Here we present crystal structures of human NEIL1 bound to a range of duplex DNA. Together with computational and biochemical analyses, our results suggest that NEIL1 promotes tautomerization of thymine glycol (Tg)-a preferred substrate-for optimal binding in its active site. Moreover, this tautomerization event also facilitates NEIL1-catalyzed Tg excision. To our knowledge, the present example represents the first documented case of enzyme-promoted tautomerization for efficient substrate recognition and catalysis in an enzyme-catalyzed reaction.

Axon Initial Segment Structural Plasticity is Involved in Seizure Susceptibility in a Rat Model of Cortical Dysplasia.

Cortical dysplasia is the most common etiology of intractable epilepsy. Both excitability changes in cortical neurons and neural network reconstitution play a role in cortical dysplasia epileptogenesis. Recent research shows that the axon initial segment, a subcompartment of the neuron important to the shaping of action potentials, adjusts its position in response to changes in input, which contributes to neuronal excitability and local circuit balance. It is unknown whether axon initial segment plasticity occurs in neurons involved in seizure susceptibility in cortical dysplasia. Here, we developed a "Carmustine"- "pilocarpine" rat model of cortical dysplasia and show that it exhibits a lower seizure threshold, as indicated by behavior studies and electroencephalogram monitoring. Using immunofluorescence, we measured the axon initial segment positions of deep L5 somatosensory neurons and show that it is positioned closer to the soma after acute seizure, and that this displacement is sustained in the chronic phase. We then show that Nifedipine has a dose-dependent protective effect against axon initial segment displacement and increased seizure susceptibility. These findings further our understanding of the pathophysiology of seizures in cortical dysplasia and suggests Nifedipine as a potential therapeutic agent.

Attitudes toward epilepsy among medical staffs in basic-level hospitals from southern China.

OBJECTIVE: The objectives of the study were to assess attitudes toward epilepsy among medical staffs from basic-level hospitals in southern China and identify significant predictive factors for future stigma reduction interventions. METHODS: The Public Attitudes Toward Epilepsy (PATE) scale, a two dimensional 14-item scale addressing two major domains: general domain and personal domain, was administered to 448 medical staffs from basic-level hospitals in southern China. Positively stated items in the PATE scale were reversely scored; in this case, a higher score would indicate a more negative attitude. Also, we compared the overall score and per-item scores of the medical staffs versus those of the general population reported in the previous studies using the same scale. RESULTS: The cumulative score of the medical staffs was 41.65 ±â€¯6.99, which is significantly lower as compared with 51.38 ±â€¯6.80 of the general population (t (645) = -16.473, p < 0.001). The general average score (t (645) = -16.473, p < 0.001) and the mean score in the general domain (t (645) = -22.573, p < 0.001) of the PATE scale were both significantly lower in the medical staffs compared with the general population, whereas there was no significant difference between the two groups in the personal domain (t(645) = -0.180, p = 0.857). Age or years in clinical practice, specialty, and title had a significant impact on both the general domain and personal domain. Residence was the only factor found affecting the medical staffs' attitudes toward epilepsy in the personal domain but not in the general domain. CONCLUSION: Medical staffs from basic-level hospitals in southern China demonstrate significant positive attitudes toward people with epilepsy in general aspects when compared with the general population. However, they still showed negative and conservative attitudes when it comes to the personal domain. Future strategies for stigma-reducing public interventions could focus on increasing better understanding of epilepsy among medical staffs in basic-level hospitals in China.

ent-Jungermannenone C Triggers Reactive Oxygen Species-Dependent Cell Differentiation in Leukemia Cells.

Acute myeloid leukemia (AML) is a hematologic malignancy that is characterized by clonal proliferation of myeloid blasts. Despite the progress that has been made in the treatment of various malignant hematopoietic diseases, the effective treatment of AML remains very challenging. Differentiation therapy has emerged as a promising approach for leukemia treatment, and new and effective chemical agents to trigger the differentiation of AML cells, especially drug-resistant cells, are urgently required. Herein, the natural product jungermannenone C, a tetracyclic diterpenoid isolated from liverworts, is reported to induce cell differentiation in AML cells. Interestingly, the unnatural enantiomer of jungermannenone C (1) was found to be more potent than jungermannenone C in inducing cell differentiation. Furthermore, compound 1 targets peroxiredoxins I and II by selectively binding to the conserved cysteine residues and leads to cellular reactive oxygen species accumulation. Accordingly, ent-jungermannenone C (1) shows potential for further investigation as an effective differentiation therapy against AML.

Identification of spirobisnaphthalene derivatives with anti-tumor activities from the endophytic fungus Rhytidhysteron rufulum AS21B.

The cultivation of the mangrove-derived fungus Rhytidhysteron rufulum AS21B in acidic condition changed its secondary metabolite profile. Investigation of the culture broth extract led to the isolation and identification of two new spirobisnaphthalenes (1 and 2) together with eleven known compounds (3-13) from the crude extract of the fungus grown under an acidic condition as well as six known compounds (4, 10, 14-17) were isolated from the crude extract of the fungus grown under a neutral condition. Their structures were elucidated on the basis of extensive spectroscopic data. The isolated compounds were evaluated for their cytotoxicity against two human cancer cell lines, Ramos lymphoma and drug resistant NSCLC H1975. Compounds 2 and 10 displayed the most promising anti-tumor activity against both cancer cell lines.

Validation of the Chinese version of public attitudes toward epilepsy scale in Mainland China.

PURPOSE: Epilepsy is a significant yet seriously underappreciated public health issue in Mainland China. The stigma and discrimination toward people with epilepsy (PWE) and their families are especially severe in China based on cultural misconceptions which cause tremendous psychological, economic and social burdens. It is imperative to formulate a targeted public intervention to eliminate knowledge gaps and correct these misconceptions of epilepsy. However, to date, the essential tools that may drive such an intervention by measuring the public perspective on PWEs is lacking in China. The goal of this study is to test the reliability and validity of a Simplified Chinese version of the "Public Attitude Toward Epilepsy" scale (PATE) in Mainland China which can be used to understand the content and identify the possible sources of stigma to better inform the design and focus of future stigma reduction interventions. METHODS: The standard procedure of cross-cultural adaptation was used in the translation process. Subjects from different economic and social backgrounds were enrolled by convenience sampling in central China. Exploratory factor analysis and confirmatory factor analysis were used to check the underlying factor structure of the items. Furthermore, Cronbach's alpha was utilized to assess internal consistency. RESULTS: 199 respondents were included in the final analysis. Content validity of this Chinese PATE was assessed to be adequate for assessing public attitudes toward epilepsy among the mainland Chinese. Two factors were extracted from the data by exploratory factor analysis; confirmatory factor analysis further confirmed good consistency of theoretical constructs between the original Public Attitudes Toward Epilepsy scale and our Chinese PATE. Our Chinese PATE presented excellent internal consistency (α=0.853-0.909). CONCLUSION: This version of the Chinese PATE showed acceptable psychometric properties, indicating that it can be implemented in surveying public attitudes toward epilepsy in Mainland China.

Rats with Malformations of Cortical Development Exhibit Decreased Length of AIS and Hypersensitivity to Pilocarpine-Induced Status Epilepticus.

Malformations of cortical development (MCD) are critical brain development disorders associated with varied abnormalities in both anatomic structures and neural functioning. It is also a very common etiology to the epilepsy, in which the alteration on excitability of cortical neurons is hypothesized as one of important causes to the epileptic seizures. Due to the key role in regulating neuron firing properties, the plasticity of axon initial segment (AIS) was investigated in present study to further determine the relation between MCD and epilepsy. Our results showed a prolonged decrease in the length of AIS occurred in MCD animal models. Besides, the AIS was also found greatly shortened in MCD models during the acute, but not chronic phase of status epileptics compared with intact controls. Our findings of identification of AIS plasticity in MCD animal models and its hypersensitivity to status epilepsy are significant in furthering our understanding of the pathophysiological mechanisms involved in this disorder.

Serum concentration of high-mobility group box 1, Toll-like receptor 4 as biomarker in epileptic patients.

Epilepsy is one of the most common neurological diseases with severe outcome. High-mobility Group Box 1/Toll-like Receptor 4 axis is proposed to participate in the epileptogenesis and correlate with seizure severity in animal models. To explore whether HMGB1 and TLR4 could serve as clinical biomarkers in epileptic patients, we recruited a total of 72 epilepsy patients and measured the serum level of HMGB1 and TLR4 by flow fluorescence technology and ELISA respectively. We found that the serum levels of HMGB1 and TLR4 were elevated in epileptic patients. The serum levels of HMGB1 and TLR4 were also significantly higher in drug-resistant group compared with drug-effective group. There was a positive linear correlation between HMGB1 and TLR4 in the study group (R2 = 0.479). The HMGB1 level was found to be related to seizures frequency (F = 6.71, P = 0.012), the duration of disease (F = 6.55, P = 0.013) and drug reactivity (F = 3.96, P = 0.024) in epileptic patients, while TLR4 level was related to seizures frequency (F = 4.68, P = 0.034) and drug reactivity (F = 3.80, P = 0.027). Our result provides experimental evidences that the expression of HMGB1 and TLR4 was correlated with clinical symptom in epileptic patients, which could be used as clinical biomarkers to monitor therapeutic effect.

Polycarcin V induces DNA-damage response and enables the profiling of DNA-binding proteins.

To maintain genomic integrity and avoid diseases, the DNA-damage response (DDR) not only detects and repairs DNA lesions, but also contributes to the resistance to DNA-damaging chemotherapeutics. Targeting the DDR plays a significant role in drug discovery using the principle of synthetic lethality. The incomplete current knowledge of the DDR encouraged us to develop new strategies to identify and study its components and pathways. Polycarcin V, belonging to the C-aryl glycoside natural products, is a light-activatable DNA-intercalating agent that causes DNA damage by forming a covalent [2+2] cycloadduct with thymine residue under 365-450 nm of light irradiation in a DNA-sequence-independent manner. Taking advantage of the light-activatable feature and temporal control of DDR, we designed and synthesized polycarcin V-based bifunctional chemical probes, including one that cross-links DNA to DNA-binding protein to explore the DDR induced by polycarcin V and uncover novel DNA-protein interactions. Utilizing this chemical probe and activity-based protein profiling-stable isotope labeling with amino acids in cell culture, we identified 311 DNA-binding protein candidates, including known DDR factors and additional proteins that may be of interest in discovering new biology. We validated our approach by showing that our probe could specifically cross-link proteins involved in nucleotide excision repair (NER) that repair bulky DNA adducts. Our studies showed that the [2+2] cycloadduct formed by polycarcin V could indeed be repaired by NER in vivo. As a DNA-damaging agent, polycarcin V or its drug-like derivative plus blue light showed promising properties for psoriasis treatment, suggesting that it may itself hold promise for clinic applications.

Establishment and Validation of a Predictive Model for Radiation-Associated Aspiration Pneumonia in Patients with Radiation-Induced Dysphagia after Nasopharyngeal Carcinoma.

Introduction: Radiotherapy for patients with head and neck cancers raises their risk of aspiration pneumonia-related death. We aimed to develop and validate a model to predict radiation-associated aspiration pneumonia (RAP) among patients with dysphagia after radiotherapy for nasopharyngeal carcinoma (NPC). Materials and Methods: A total of 453 dysphagic patients with NPC were retrospectively recruited from Sun Yat-Sen Memorial Hospital from January 2012 to January 2018. Patients were randomly divided into training cohort (n = 302) and internal validation cohort (n = 151) at a ratio of 2 : 1. The concordance index (C-index) and calibration curve were used to evaluate the accuracy and discriminative ability of this model. Moreover, decision curve analysis was performed to evaluate the net clinical benefit. The results were externally validated in 203 dysphagic patients from the First People's Hospital of Foshan. Results: Derived from multivariable analysis of the training cohort, four independent factors were introduced to predict RAP, including Kubota water drinking test grades, the maximum radiation dose of lymph node gross tumor volume (Dmax of the GTVnd), neutrophil count, and erythrocyte sedimentation rate (ESR). The nomogram showed favorable calibration and discrimination regarding the training cohort, with a C-index of 0.749 (95% confidence interval (CI), 0.681 to 0.817), which was confirmed by the internal validation cohort (C-index 0.743; 95% CI, 0.669 to 0.818) and the external validation cohort (C-index 0.722; 95% CI, 0.606 to 0.838). Conclusions: Our study established and validated a simple nomogram for RAP among patients with dysphagia after radiotherapy for NPC.

Efficacy and Safety of Apatinib for Radiation-induced Brain Injury Among Patients With Head and Neck Cancer: An Open-Label, Single-Arm, Phase 2 Study.

PURPOSE: The treatment of radiation-induced brain injury (RI) caused by radiation therapy for head and neck cancer is challenging. Antiangiogenic therapy is a promising treatment. Apatinib is an oral tyrosine kinase inhibitor that selectively inhibits vascular endothelial growth factor receptor 2. We aimed to assess the efficacy and safety of apatinib in patients with RI. METHODS AND MATERIALS: In this phase 2, open-label, single-arm, prospective study, we recruited patients aged 35 to 80 years with prior radiation therapy history for head and neck cancer who had newly diagnosed RI at the Sun Yat-sen Memorial Hospital, China. Apatinib was administered at a dosage of 250 mg once daily orally for 4 weeks. A Simon minimax 2-stage design was performed. The primary outcome was the proportion of patients with overall clinical efficacy, defined as a radiographic response of ≥25% reduction in baseline brain edema volume on magnetic resonance fluid attenuated inversion recovery images at week 4. Secondary end points were the overall improvement rate of brain necrosis, neurologic function, and safety. RESULTS: We screened 37 patients, 36 of whom were enrolled between October 17, 2019, and August 3, 2020. At the cutoff date, 36 patients were assessed for efficacy and safety (19 were enrolled in stage 1 and 17 in stage 2). Of the 36 patients evaluated for overall clinical efficacy, 22 patients (61.1%; 95% CI, 43.5%-76.9%) achieved the primary end point at week 4. Among the 31 patients with brain necrosis lesions, 19 patients (61.3%; 95% CI, 42.2%-78.2%) showed improvement of brain necrosis. The most common grade 1 to 2 adverse events were hand-foot syndrome, fatigue, and hypertension There were no treatment-related grade 4 to 5 toxic effects. CONCLUSIONS: Oral apatinib shows promising efficacy and is well-tolerated in patients with RI. Further randomized controlled studies are warranted.

Bevacizumab Combined with Corticosteroids Does Not Improve the Clinical Outcome of Nasopharyngeal Carcinoma Patients With Radiation-Induced Brain Necrosis.

OBJECTIVE: Our aim was to compare the clinical outcomes of patients treated with bevacizumab combined with corticosteroids and those with bevacizumab monotherapy from a radiation-induced brain necrosis (RN) registry cohort (NCT03908502). METHODS: We utilized clinical data from a prospective RN registry cohort (NCT03908502) from July 2017 to June 2020. Patients were considered eligible if they had symptomatic RN after radiotherapy for nasopharyngeal carcinoma (NPC) and received bevacizumab (5 mg/kg, two to four cycles) with a minimum follow-up time of 3 months. The primary outcome was a 2-month response rate determined by MRI and clinical symptoms. Secondary outcomes included quality of life [evaluated by the abbreviated World Health Organization Quality of Life (WHOQOL-BREF) questionnaire] and cognitive function (evaluated by the Montreal Cognitive Assessment scale) at 2 months, RN recurrence during follow-up, and adverse events. RESULTS: A total of 123 patients (34 in the combined therapy group and 89 in the monotherapy group) were enrolled in our study with a median follow-up time of 0.97 year [interquartile range (IQR) = 0.35-2.60 years]. The clinical efficacy of RN did not differ significantly between patients in these two groups [odds ratio (OR) = 1.642, 95%CI = 0.584-4.614, p = 0.347]. Furthermore, bevacizumab combined with corticosteroids did not reduce recurrence compared with bevacizumab monotherapy [hazard ratio (HR) = 1.329, 95%CI = 0.849-2.079, p = 0.213]. The most common adverse events of bevacizumab were hypertension (17.89%), followed by nosebleed (8.13%) and fatigue (8.13%). There was no difference in grade 2 or more severe adverse events between the two groups (p = 0.811). INTERPRETATION: Our results showed that the treatment strategy of combining bevacizumab with corticosteroids did not lead to better clinical outcomes for RN patients with a background of radiotherapy for nasopharyngeal carcinoma.

Syntheses of Skeletally Diverse Tetracyclic Isodon Diterpenoid Scaffolds Guided by Dienyne Radical Cyclization Logic.

We report herein the diversity-oriented synthesis of various tetracyclic Isodon diterpenoid scaffolds guided by radical cyclization logic. Our substrate-based dienyne radical cyclization approach is distinctive from reagent-based rearrangement approaches that are generally applied in biosynthesis or previous synthetic studies. An unprecedented cyclization at C14 via 1,5-radical translocation/5-exo-trig cyclization is observed, which enriches our radical cyclization pattern. Furthermore, biological evaluations revealed that several new natural product-like compounds showed promising anticancer activities against various cancer cell lines.

Computation-Guided Development of the "Click" ortho-Quinone Methide Cycloaddition with Improved Kinetics.

We report here a deep mechanistic study of the "click" ortho-quinone methide (oQM) cycloaddition between ortho-quinolinone quinone methide (oQQM) and thio-vinyl ether (TV), named as TQ-ligation. DFT calculations revealed the unexpected fact that dehydration of oQQM precursors is the rate-determining step of this transformation, and two highly reactive oQQM precursors were predicted. Guided by the calculations, a new "click" oQM cycloaddition which shows significantly improved kinetics and remarkable efficiency on protein labeling was developed.

A nomogram to predict symptomatic epilepsy in patients with radiation-induced brain necrosis.

OBJECTIVE: To develop and validate a nomogram to predict epilepsy in patients with radiation-induced brain necrosis (RN). METHODS: The nomogram was based on a retrospective analysis of 302 patients who were diagnosed with symptomatic RN from January 2005 to January 2016 in Sun Yat-sen Memorial Hospital using the Cox proportional hazards model. Discrimination of the nomogram was assessed by the concordance index (C index) and the calibration curve. The results were internally validated using bootstrap resampling and externally validated using 128 patients with RN from 2 additional hospitals. RESULTS: A total of 302 patients with RN with a median follow-up of 3.43 years (interquartile range 2.54-5.45) were included in the training cohort; 65 (21.5%) developed symptomatic epilepsy during follow-up. Seven variables remained significant predictors of epilepsy after multivariable analyses: MRI lesion volume, creatine phosphokinase, the maximum radiation dose to the temporal lobe, RN treatment, history of hypertension and/or diabetes, sex, and total cholesterol level. In the validation cohort, 28 out of 128 (21.9%) patients had epilepsy after RN within a median follow-up of 3.2 years. The nomogram showed comparable discrimination between the training and validation cohort (corrected C index 0.76 [training] vs 0.72 [95% confidence interval 0.62-0.81; validation]). CONCLUSION: Our study developed an easily applied nomogram for the prediction of RN-related epilepsy in a large RN cohort. CLASSIFICATION OF EVIDENCE: This study provides Class III evidence that a nomogram predicts post-RN epilepsy.

Investigation into attitudes toward epilepsy among non-/neurological doctors and nurses in southern China.

PURPOSE: To assess attitudes concerning epilepsy among non-/neurological medical personnel from basic-level hospitals in southern China and identify significant predictive factors for future stigma reduction interventions. METHOD: The Chinese Public Attitudes Toward Epilepsy (CPATE) scale was administered to 184 neurological and 264 non-neurological medical staff members from basic-level hospitals in southern China. Positively stated items in the PATE scale were reversely scored; in this case, a higher score would indicate a more negative attitude. RESULTS: The mean score of each item among the neurological group was statistically lower than that of the non-neurological group. The mean scores in both the general and personal domains of the CPATE scale were significantly lower among the doctors as compared to nurses. CONCLUSIONS: This was the first study to evaluate the attitudes toward epilepsy among medical personnel with different characteristics in basic-level hospitals in China. Health education can be a new model for stigma-reducing public interventions in China. Future strategies should first focus on improving access to correct knowledge about epilepsy among non-neurological medical staffs. This would be a vital breakthrough point to improve attitudes toward epilepsy in the whole society to help ease the disease burden on people with epilepsy, their families and the community in the years to come.

Mechanisms of decreased cholinergic arousal in focal seizures: In vivo whole-cell recordings from the pedunculopontine tegmental nucleus.

Focal limbic seizures often impair consciousness/awareness with major negative impact on quality of life. Recent work has shown that limbic seizures depress brainstem arousal systems, including reduced action potential firing in a key node: cholinergic neurons of the pedunculopontine tegmental nucleus (PPT). In vivo whole-cell recordings have not previously been achieved in PPT, but are used here with the goal of elucidating the mechanisms of reduced PPT cholinergic neuronal activity. An established model of focal limbic seizures was used in rats following brief hippocampal stimulation under light anesthesia. Whole-cell in vivo recordings were obtained from PPT neurons using custom-fabricated 9-10 mm tapered patch pipettes, and cholinergic neurons were identified histologically. Average membrane potential, input resistance, membrane potential fluctuations and variance were analyzed during seizures. A subset of PPT neurons exhibited reduced firing and hyperpolarization during seizures and stained positive for choline acetyltransferase. These PPT neurons showed a mean membrane potential hyperpolarization of -3.82 mV (±0.81 SEM, P < .05) during seizures, and also showed significantly increased input resistance, fewer excitatory post-synaptic potential (EPSP)-like events (P < .05), and reduced membrane potential variance (P < .01). The combination of increased input resistance, decreased EPSP-like events and decreased variance weigh against active ictal inhibition and support withdrawal of excitatory input as the dominant mechanism of decreased activity of cholinergic neurons in the PPT. Further identifying synaptic mechanisms of depressed arousal during seizures may lead to new treatments to improve ictal and postictal cognition.