Impact of subthalamic nucleus deep brain stimulation at different frequencies on neurogenesis in a rat model of Parkinson's disease.

Neurogenesis, play a vital role in neuronal plasticity of adult mammalian brains, and its dysregulation is present in the pathophysiology of Parkinson's disease (PD). While subthalamic nucleus deep brain stimulation (STN-DBS) at various frequencies has been proven effective in alleviating PD symptoms, its influence on neurogenesis remains unclear. This study aimed to investigate the effects of 1-week electrical stimulation at frequencies of 60Hz, 130Hz, and 180Hz on neurogenesis in the subventricular zone (SVZ) of PD rats. A hemiparkinsonian rat model was established using 6-hydroxydopamine and categorized into six groups: control, PD, sham stimulation, 60Hz stimulation, 130Hz stimulation, and 180Hz stimulation. Motor function was assessed using the open field test and rotarod test after one week of STN-DBS at different frequencies. Tyrosine hydroxylase (TH) expression in brain tissue was analyzed via Western blot and immunohistochemistry. Immunofluorescence analysis was conducted to evaluate the expression of BrdU/Sox2, BrdU/GFAP, Ki67/GFAP, and BrdU/DCX in bilateral SVZ and the rostral migratory stream (RMS). Our findings revealed that high-frequency STN-DBS improved motor function. Specifically, stimulation at 130Hz increased dopaminergic neuron survival in the PD rat model, while significantly enhancing the proliferation of neural stem cells (NSCs) and neuroblasts in bilateral SVZ. Moreover, this stimulation effectively facilitated the generation of new NSCs in the ipsilateral RMS and triggered the emergence of fresh neuroblasts in bilateral RMS, with notable presence within the lesioned striatum. Conversely, electrical stimulation at 60Hz and 180Hz did not exhibit comparable effects. The observed promotion of neurogenesis in PD rats following STN-DBS provides valuable insights into the mechanistic basis of this therapeutic approach for PD.

Relationship between plasma brain-derived neurotrophic factor levels and neurological disorders: An investigation using Mendelian randomisation.

Background: Altered brain-derived neurotrophic factor (BDNF) concentrations have been detected in the central nervous system tissues and peripheral blood. These alterations are associated with a series of neurological disorders. Objective: To investigate the potential causal relationships between genetically determined plasma BDNF levels and various neurological diseases using a two-sample Mendelian randomisation study. Methods: We selected single nucleotide polymorphisms strongly related to plasma BDNF levels as instrumental variables. Within the Mendelian randomisation framework, we used summary-level statistics for exposure (plasma BDNF levels) and outcomes (neurological disorders). Results: We observed suggestive evidence of a relation between higher plasma BDNF levels and less risk of nontraumatic intracranial haemorrhage (nITH) (odds ratio [OR] = 0.861, 95 % confidence interval [CI]: 0.774-0.958, P = 0.006, PFDR = 0.078), epilepsy (OR = 0.927, 95 % CI: 0.880-0.976, P = 0.004, PFDR = 0.078), focal epilepsy (OR = 0.928, 95 % CI: 0.874-0.986, P = 0.016, PFDR = 0.139), and non-lesional focal epilepsy (OR = 0.981, 95 % CI: 0.964-0.999, P = 0.041, PFDR = 0.267). Combined with the UK Biobank dataset, the association of plasma BDNF levels with nITH remained significant (OR = 0.88, 95 % CI: 0.81-0.96, P < 0.01). The combined analysis of three consortium datasets demonstrated a considerable impact of plasma BDNF on epilepsy (OR = 0.94, 95 % CI: 0.90-0.98, P < 0.01) and a suggestive impact on focal epilepsy (OR = 0.94, 95 % CI: 0.89-0.99, P = 0.02). However, there was no apparent correlation between plasma BDNF levels and other neurological disorders or related subtypes. Conclusions: Our study supports a possible causal relationship between elevated plasma BDNF levels and a reduced risk of nITH, epilepsy, and focal epilepsy.

The role of magnetoencephalography in preoperative localization and postoperative outcome prediction in patients with posterior cortical epilepsy.

OBJECTIVE: We aimed to explore the value of magnetoencephalography in the presurgical evaluation of patients with posterior cortex epilepsy. METHODS: A total of 39 patients with posterior cortex epilepsy (PCE) and intact magnetoencephalography (MEG) images were reviewed from August 2019 to July 2022. MEG dipole clusters were classified into single clusters, multiple clusters, and scatter dipoles based on tightness criteria. The association of the surgical outcome with MEG dipole classifications was evaluated using Fisher's exact tests. RESULTS: Among the 39 cases, there were 24 cases of single clusters (61.5%), nine cases of multiple clusters (23.1%), and six cases of scattered dipoles (15.4%). Patients with single dipole clusters were more likely to become seizure-free. Among single dipole cluster cases (n = 24), complete MEG dipole resection yielded a more favorable surgical outcome than incomplete resection (83.3% vs. 16.7%, p = 0.007). Patients with concordant MRI and MEG findings achieved a significantly more favorable surgical outcome than discordant patients (66.7% vs. 33.3%, p = 0.044), especially in single dipole cluster patients (87.5% vs. 25.0%, p = 0.005). SIGNIFICANCE: MEG can provide additional valuable information regarding surgical candidate selection, epileptogenic zone localization, electrode implantation schedule, and final surgical planning in patients with posterior cortex epilepsy.

Radiomics features from 3D-MPRAGE imaging can differentiate temporal-plus epilepsy from temporal lobe epilepsy.

OBJECTIVE: This study aimed to differentiate temporal-plus epilepsy (TPE) from temporal lobe epilepsy (TLE) using extraction of radiomics features from three-dimensional magnetization-prepared rapid acquisition gradient echo (3D-MPRAGE) imaging data. METHODS: Data from patients with TLE or TPE who underwent epilepsy surgery between January 2019 and January 2021 were retrospectively analyzed. Thirty-three regions of interest in the affected hemisphere of each patient were defined on 3D-MPRAGE images. A total of 3531 image features were extracted from each patient. Four feature selection methods and 10 machine learning algorithms were used to build 40 differentiation models. Model performance was evaluated using receiver operating characteristic analysis. RESULTS: Eighty-two patients were included for analysis, 47 with TLE and 35 with TPE. The model combining logistic regression and the relief selection method had the best performance (area under the receiver operating characteristic curve, .779; accuracy, .875; sensitivity, .800; specificity, .929; positive predictive value, .889; negative predictive value, .867). SIGNIFICANCE: Radiomics analysis can differentiate TPE from TLE. The logistic regression classifier trained with radiomics features extracted from 3D-MPRAGE images had the highest accuracy and best performance.

Deep brain stimulation for patients with refractory epilepsy: nuclei selection and surgical outcome.

Objective: By studying the surgical outcome of deep brain stimulation (DBS) of different target nuclei for patients with refractory epilepsy, we aimed to explore a clinically feasible target nucleus selection strategy. Methods: We selected patients with refractory epilepsy who were not eligible for resective surgery. For each patient, we performed DBS on a thalamic nucleus [anterior nucleus of the thalamus (ANT), subthalamic nucleus (STN), centromedian nucleus (CMN), or pulvinar nucleus (PN)] selected based on the location of the patient's epileptogenic zone (EZ) and the possible epileptic network involved. We monitored the clinical outcomes for at least 12 months and analyzed the clinical characteristics and seizure frequency changes to assess the postoperative efficacy of DBS on the different target nuclei. Results: Out of the 65 included patients, 46 (70.8%) responded to DBS. Among the 65 patients, 45 underwent ANT-DBS, 29 (64.4%) responded to the treatment, and four (8.9%) of them reported being seizure-free for at least 1 year. Among the patients with temporal lobe epilepsy (TLE, n = 36) and extratemporal lobe epilepsy (ETLE, n = 9), 22 (61.1%) and 7 (77.8%) responded to the treatment, respectively. Among the 45 patients who underwent ANT-DBS, 28 (62%) had focal to bilateral tonic-clonic seizures (FBTCS). Of these 28 patients, 18 (64%) responded to the treatment. Out of the 65 included patients, 16 had EZ related to the sensorimotor cortex and underwent STN-DBS. Among them, 13 (81.3%) responded to the treatment, and two (12.5%) were seizure-free for at least 6 months. Three patients had Lennox-Gastaut syndrome (LGS)-like epilepsy and underwent CMN-DBS; all of them responded to the treatment (seizure frequency reductions: 51.6%, 79.6%, and 79.5%). Finally, one patient with bilateral occipital lobe epilepsy underwent PN-DBS, reducing the seizure frequency by 69.7%. Significance: ANT-DBS is effective for patients with TLE or ETLE. In addition, ANT-DBS is effective for patients with FBTCS. STN-DBS might be an optimal treatment for patients with motor seizures, especially when the EZ overlaps the sensorimotor cortex. CMN and PN may be considered modulating targets for patients with LGS-like epilepsy or occipital lobe epilepsy, respectively.

Discriminative neural pathways for perception-cognition activity of color and face in the human brain.

Human performance can be examined using a visual lens. The identification of psychophysical colors and emotional faces with perceptual visual pathways may remain invalid for simple detection tasks. In particular, how the visual dorsal and ventral processing streams handle discriminative visual perceptions and subsequent cognition activities are obscure. We explored these issues using stereoelectroencephalography recordings, which were obtained from patients with pharmacologically resistant epilepsy. Delayed match-to-sample paradigms were used for analyzing the processing of simple colors and complex emotional faces in the human brain. We showed that the angular-cuneus gyrus acts as a pioneer in discriminating the 2 features, and dorsal regions, including the middle frontal gyrus (MFG) and postcentral gyrus, as well as ventral regions, such as the middle temporal gyrus (MTG) and posterior superior temporal sulcus (pSTS), were involved in processing incongruent colors and faces. Critically, the beta and gamma band activities between the cuneus and MTG and between the cuneus and pSTS would tune a separate pathway of incongruency processing. In addition, posterior insular gyrus, fusiform, and MFG were found for attentional modulation of the 2 features via alpha band activities. These findings suggest the neural basis of the discriminative pathways of perception-cognition activities in the human brain.

The clinico-pathological characterisation of focal cortical dysplasia type IIb genetically defined by MTOR mosaicism.

AIMS: Focal cortical dysplasia (FCD) is a major cause of drug-resistant paediatric epilepsy and is amenable to successful neurosurgical resection. FCD ILAE Type IIb is the most common FCD subtype, and brain somatic mutations affecting the mTOR pathway play a major pathogenic role. The aim of this study was to comprehensively describe the genotype-phenotype association of 20 patients with histopathologically confirmed FCDIIb using next generation sequencing (NGS) of paired blood-brain samples. METHODS: Clinical and neuropathological data were retrospectively reviewed from the hospital archive. The NGS panel included 11 mTOR-pathway-related genes with maximum coverage of 2000×. The detected variants were validated by digital droplet PCR. RESULTS: Pathogenic MTOR variants were identified in 10 patients (50%). Further comparison with MTOR-wildtype FCDIIb suggested a profound genotype-phenotype association characterised by (1) a non-temporal lobe lesion on MRI, (2) a larger lesion volume occupying grey and white matter (3.032 ± 1.859 cm3 vs 1.110 ± 0.856 cm3 , p = 0.014), (3) more balloon cells (50.20 ± 14.40 BC/mm2 vs 31.64 ± 30.56 BC/mm2 , p = 0.099) and dysmorphic neurons (48.72 ± 19.47DN/mm2 vs 15.28 ± 13.95DN/mm2 , p = 0.000) and (4) a positive correlation between VAF and the lesion volume (r = 0.802, p = 0.017). CONCLUSIONS: Our study identified frequent MTOR mutations in the cell-rich FCDIIb phenotype, clinically characterised by a non-temporal location and large lesion volume. Comprehensive genotype-phenotype associations will help us further explore and define the broad spectrum of FCD lesions to make more targeted therapies available in the realm of epileptology.

Global trends in research of glutamate in epilepsy during past two decades: A bibliometric analysis.

Epilepsy affects more than 70 million people in the world. It is characterized by recurrent spontaneous seizures, and it is related to many neurological, cognitive, and psychosocial consequences. Glutamate neurotransmitter dysfunction has essential functions in the pathophysiology of epilepsy. In this work, bibliometric analysis was conducted to explore the trends, frontiers, and hotspots of the global scientific output of glutamate in epilepsy research in the past 20 years. The Science Citation Index Expanded of the Web of Science Core Collection (WoSCC) was searched to obtain information on publications and records published between 2002 and 2021. VOSviewer and CiteSpace were used to conduct bibliometric and visual analyses on the overall distribution of annual output, major countries, active institutions, journals, authors, commonly cited literature, and keywords. The impact and quality of the papers were assessed using the global citation score (GCS). Four thousand eight hundred ninety-one publications were retrieved in total. During the past two decades, the number of publications (Np) associated with glutamate in epilepsy has risen yearly. The United States has published the most papers; its H-index and number of citations are also the highest. The League of European Research Universities (LERU) was the most productive institution. In 2016, the total score of the paper written by Zhang Y was 854, ranking first. The keywords that appear most frequently are "epilepsy," "glutamate," "temporal lobe epilepsy (TLE)," "hippocampus," and "seizures." This study showed that although the publications related to epileptic glutamate fluctuated slightly, the Np increased overall. The United States is a great creator and influential country in this field. The first three authors are Eid, T., Aronica, E., and Smolders, I. "spectrum," "animal model," "inflammation," "mutation," "dysfunction," and "prefrontal cortex" are increasing research hotspots. By recognizing the most critical indicators (researchers, countries, research institutes, and journals of glutamate release in epilepsy research), the research hotspot of glutamate in epilepsy could help countries, scholars, and policymakers in this field enhance their understanding of the role of glutamate in epilepsy and make decisions.

Temporal-insular spreading time in temporal lobe epilepsy as a predictor of seizure outcome after temporal lobectomy.

Insular involvement in temporal lobe epilepsy (TLE) has gradually been recognized since the widespread use of stereoelectroencephalography (SEEG). However, the correlation between insular involvement and failed temporal lobe surgery remains unclear. In this study, we analyzed the surgical outcomes of TLE patients who underwent temporal and insular SEEG recordings and explored the predictors of failed anterior temporal lobectomy (ATL) in these patients with temporal seizures. Forty-one patients who underwent ATL for drug-resistant TLE were examined using temporal and insular SEEG recordings. The clinical characteristics, SEEG data, and postoperative seizure outcomes of these patients were analyzed, and multivariate analysis was used to identify the predictors of surgical outcome. In this series, the ictal temporal discharges invaded the insula in 39 (95.1%) patients. Twenty-three (56.1%) patients were seizure-free (Engel class I) after ATL with at least 1 year follow-up. Only temporal-insular spreading time (TIST) was an independent predictor of postoperative seizure-free outcomes (P = .035). By creating receiver operating characteristic curves for TIST, 400 milliseconds was identified as the cutoff for classification. All patients were classified into 2 groups (TIST ≤ 400 milliseconds and TIST > 400 milliseconds) based on the cutoff value; the difference in seizure-free rates between the 2 groups was significant (P = .001). The very early insular involvement in TLE may be associated with poorer seizure outcomes after ATL. Our findings may be helpful for estimating the appropriate operative procedures and will be valuable for evaluating the prognosis of TLE patients with temporal-insular SEEG recordings and temporal lobectomy.

Ictal onset stereoelectroencephalography patterns in temporal lobe epilepsy: type, distribution, and prognostic value.

OBJECTIVE: The aim of this study was to investigate the different ictal onset stereoelectroencephalography patterns (IOPs) in patients with drug-resistant temporal lobe epilepsy (TLE). We examined whether the IOPs relate to different TLE subtypes, MRI findings, and underlying pathologies, and we evaluated their prognostic value for predicting the surgical outcome. METHODS: We retrospectively analyzed data from patients with TLE who underwent stereoelectroencephalography (SEEG) monitoring followed by surgical resection between January 2018 and January 2020. The SEEG recordings were independently analyzed by two epileptologists. RESULTS: Forty-five patients were included in the study, and 61seizures were analyzed. Five IOPs were identified: low voltage fast activity (LVFA; 44.3%), spike-and-wave activity (16.4%), low frequency high-amplitude periodic spikes (LFPS; 18%), a burst of high-amplitude polyspikes (8.2%), and rhythmic sharp activity at ≤ 13 Hz (13.1%). Thirty-two patients were found to have a single IOP, while the other 13 patients had two or more IOPs. All five IOPs were found to occur in the medial temporal lobe epilepsy (MTLE), while four IOPs occurred in the lateral temporal lobe epilepsy (LTLE). The LFPS was a common IOP that could distinguish MTLE from LTLE (x2 = 7.046, p = 0.011). Among the MTLE patients, the LFPS was exclusively seen in cases of hippocampal sclerosis (x2 = 5.058, p = 0.038), while the LVFA was associated with nonspecific histology (x2 = 6.077, p = 0.023). The IOPs were not found to differ according to whether the MRI scans were positive or negative. After surgery, patients achieved the higher seizure-free rate at 81.8% and 77.8%, respectively, if the LFPS and LVFA were the predominant patterns. Multiple IOPs or a negative MRI did not indicate a poor prognosis. CONCLUSIONS: Five distinct IOPs were identified in the patients with TLE. The differences found have important clinical implications and could provide complementary information for surgical decision-making, especially in MRI-negative patients.

Fluid and White Matter Suppression Imaging and Voxel-Based Morphometric Analysis in Conventional Magnetic Resonance Imaging-Negative Epilepsy.

Purpose: Delineation of subtle lesions in magnetic resonance imaging (MRI)-negative patients is of great importance in preoperative epilepsy evaluation. The aim of our study was to explore the diagnostic value of the novel fluid and white matter suppression (FLAWS) sequence in comparison with a voxel-based MRI postprocessing morphometric analysis program (MAP) in a consecutive cohort of non-lesional patients. Methods: Surgical candidates with a negative finding on an official neuroradiology report were enrolled. High-resolution FLAWS image and MAP maps generated based on high-resolution three-dimensional (3D) T1 image were visually inspected for each patient. The findings of FLAWS or MAP-positive (FLAWS/MAP+) regions were compared with the surgical resection cavity in correlation with surgical outcome and pathology. Results: Forty-five patients were enrolled; the pathological examination revealed focal cortical dysplasia (FCD) in 32 patients and other findings in 13 patients. The positive rate, sensitivity, and specificity were 48.9%, 0.43, and 0.87, respectively, for FLAWS and 64.4%, 0.57, and 0.8, respectively, for MAP. Concordance between surgical resection and FLAWS+ or MAP+ regions was significantly associated with a seizure-free outcome (FLAWS: p = 0.002; MAP: p = 0.0003). A positive finding in FLAWS and MAP together with abnormalities in the same gyrus (FLAWS-MAP gyral+) was detected in 31.1% of patients. FLAWS+ only and MAP+ only were found in 7 (15.5%) and 14 (31.1%) patients, respectively. Conclusions: FLAWS showed a promising value for identifying subtle epileptogenic lesions and can be used as a complement to current MAP in patients with MRI-negative epilepsy.

Voxel-based morphometric MRI post-processing and PET/MRI co-registration reveal subtle abnormalities in cingulate epilepsy.

OBJECTIVE: Diagnostic challenges exist in the presurgical evaluation of patients with magnetic resonance imaging (MRI) negative cingulate epilepsy (CE) because of the heterogeneity in clinical semiology and lack of localizing findings on scalp electroencephalographic (EEG) recordings. We aimed to examine the neuroimaging characteristics in a consecutive cohort of patients with MRI-negative CE with a focus on two image post-processing methods, including the MRI post-processing morphometric analysis program (MAP) and 18F-fluorodeoxyglucose-positron emission tomography-MRI (PET/MRI) co-registration. METHODS: Included in this retrospective study were patients with MRI-negative CE who met the following criteria: negative on preoperative MRI, invasive EEG (iEEG) confirmed cingulate gyrus-onset seizures, surgical resection of the cingulate gyrus with/without adjacent cortex, and seizure-free for more than 12 months. MAP and PET/MRI co-registration were performed and investigated by comparison to ictal intracranial EEG findings. Other characteristics obtained from scalp EEG, magnetoencephalography (MEG), iEEG, and pathological study were also reported. RESULTS: Ten patients were included, of which eight were diagnosed with anterior CE, one with middle CE, and one with posterior CE. The semiology included fear, embarrassment, vocalization, ictal pouting, asymmetric tonic posture, hypermotor, and automatism. Scalp EEG revealed unilateral or bilateral frontal-temporal onset. MEG localized the dipoles correctly in one patient (1/10). MAP detected subtle abnormalities in regions concordant with iEEG onset in seven patients (7/10) while PET/MRI co-registration revealed focal concordant hypometabolism in five patients (5/10). Combining MAP with PET/MRI co-registration improved the detection rate to 90 % in this cohort. The pathology was focal cortical dysplasia (FCD), including FCD type IIA in three, type IIB in three, and type I in four. CONCLUSION: MAP and PET/MRI co-registration show promising results in identifying subtle FCD abnormalities in CE with negative results on conventional MRI, which can be otherwise challenging. More importantly, a combination of MRI post-processing and PET/MRI co-registration can greatly improve the identification of epileptic abnormalities, which can be used as surgical target. MAP and PET/MRI co-registration should be incorporated into the routine presurgical evaluation.

Functional organization of the human primary somatosensory cortex: A stereo-electroencephalography study.

OBJECTIVE: The classical homunculus of the human primary somatosensory cortex (S1) established by Penfield has mainly portrayed the functional organization of convexial cortex, namely Brodmann area (BA) 1. However, little is known about the functions in fissural cortex including BA2 and BA3. We aim at drawing a refined and detailed somatosensory homunculus of the entire S1. METHODS: We recruited 20 patients with drug-resistant focal epilepsy who underwent stereo-electroencephalography for preoperative assessments. Direct electrical stimulation was performed for functional mapping. Montreal Neurological Institute coordinates of the stimulation sites lying in S1 were acquired. RESULTS: Stimulation of 177 sites in S1 yielded 149 positive sites (84%), most of which were located in the sulcal cortex. The spatial distribution of different body-part representations across the S1 surface revealed that the gross medial-to-lateral sequence of body representations within the entire S1 was consistent with the classical "homunculus". And we identified several unreported body-part representations from the sulcal cortex, such as forehead, deep elbow and wrist joints, and some dorsal body regions. CONCLUSIONS: Our results reveal general somatotopical characteristics of the entire S1 cortex and differences with the previous works of Penfield. SIGNIFICANCE: The classical S1 homunculus was extended by providing further refinement and additional detail.

Auras in intractable frontal lobe epilepsy: Clinical characteristics, values, and limitations.

Auras are essential in preoperative evaluation and can provide valuable information for delineating seizure onset zones. Frontal lobe epilepsy (FLE) is the second most common focal epilepsy, while a few studies have focused on auras in FLE. To better understand FLE, we analyzed the clinical characteristics, values, and limitations of auras in FLE. The incidence rate of aura in FLE was 37.9% in our study. We included 54 patients and 76 auras in 11 categories were reported. The rate of auras in the decreasing order are as follows: autonomic aura; emotional aura; somatosensory aura; psychic aura; cephalic aura; abdominal aura; whole-body sensory aura, visual aura; auditory aura; and vestibular and unclassified aura. A significant number of aura types can be reported by FLE patients; autonomic aura was the most frequent category and somatosensory auras are most likely associated with the contralateral motor areas.

A study of medial and lateral temporal lobe epilepsy based on stereoelectroencephalography.

BACKGROUND: Patients with temporal lobe epilepsy (TLE) originating from different seizure onset zones had distinct electrophysiological characteristics and surgical outcomes. In this study, we aimed to investigate the relationship between the origin and prognosis of TLE, and the stereoelectroencephalography (SEEG) features. METHODS: Thirty patients with TLE, who underwent surgical treatment in our functional neurosurgery department from January 2016 to December 2017, were enrolled in this study. All patients underwent anterior temporal lobectomy after an invasive pre-operative evaluation with SEEG. Depending on the epileptic focus location, patients were divided into those with medial temporal lobe seizures (MTLS) and those with lateral temporal lobe seizures (LTLS). The Engel classification was used to evaluate operation effectiveness, and the Kaplan-Meier analysis was used to detect seizure-free duration. RESULTS: The mean follow-up time was 25.7 ±â€Š4.8 months. Effectiveness was 63.3% for Engel I (n = 19), 13.3% for Engel II, 3.3% for Engel III, and 20.0% for Engel IV. According to the SEEG, 60.0% (n = 18) had MTLS, and 40.0% (n = 12) had LTLS. Compared with the MTLS group, the operation age of those with LTLS was significantly greater (26.9 ±â€Š6.9 vs. 29.9 ±â€Š12.5 years, t = -0.840, P = 0.009) with longer epilepsy duration (11.9 ±â€Š6.0 vs. 17.9 ±â€Š12.1 years, t = -1.801, P = 0.038). Patients with MTLS had a longer time interval between ictal onset to seizure (67.3 ±â€Š59.1 s vs. 29.3 ±â€Š24.4 s, t = 2.017, P = 0.008). The most common SEEG ictal pattern was a sharp/spike-wave rhythm in the MTLS group (55.6%) and low-voltage fast activity in the LTLS group (58.3%). Compared with the LTLS group, patients with MTLS had a more favorable prognosis (41.7% vs. 77.8%, P = 0.049). Post-operative recurrence was more likely to occur within three months after the operation for both groups, and there appeared to be a stable long-term outcome. CONCLUSION: Patients with MTLS, who accounted for three-fifths of patients with TLE, showed a more favorable surgical outcome.

Multitask preoperative language mapping in epilepsy surgery: A combination of navigated transcranial magnetic stimulation and extra-operative electrical cortical stimulation.

Navigated transcranial magnetic stimulation (nTMS) is increasingly applied in language mapping. However, the application mode and task selection of nTMS are not standardized. The aim of this study was to assessed the necessity and validity of multitask nTMS language mapping by comparing results with extraoperative electrical cortical stimulation (eoECS). In this study, sixteen epilepsy surgery patients were examined by nTMS and eoECS language mapping, and the two results were compared. The mapping results were validated with pre- to postoperative language assessments. Compared with eoECS, nTMS showed the overall sensitivity of 82.4%, specificity of 95.1%, positive predictive value of 66.7%, and negative predictive value of 97.8%. Spontaneous speech was the most sensitive task in the frontal area, naming was the sensitive task in both frontal and temporal areas. The false responses were mainly located in the perisylvian region. Multitask nTMS helps to reduce missing language relevant cortex preoperatively. Selecting spontaneous speech and naming tasks in frontal area, comprehension and naming tasks in temporal and posterior language area would strike the balance between the validity and efficiency of the mapping procedure. These results manifested the necessity of applying multitask in nTMS language mapping. Our study highlighted the importance of the nTMS evaluation mode and task selection for epilepsy patients.

The value of magnetoencephalography for stereo-EEG-guided radiofrequency thermocoagulation in MRI-negative epilepsy.

OBJECTIVE: Magnetoencephalography (MEG) is valuable for guiding resective surgery in patients with epilepsy. However, its value for minimally invasive treatment is still unknown. This study aims to evaluate the value of MEG for stereo-electroencephalogram (EEG)-guided radiofrequency thermocoagulation (SEEG-guided RF-TC) in magnetic resonance imaging (MRI)-negative epilepsies. METHODS: An observational cohort study was performed and 19 MRI-negative patients who underwent SEEG-guided RF-TC in our epilepsy center were included. In addition, 16 MRI-positive patients were included as a reference group. Semiology, electrophysiology, and imaging information were collected. To evaluate the value of locating the MEG cluster, the proportion of the RF-TC contacts located in the MEG cluster out of all contacts used to perform RF-TC in each patient was calculated. All patients underwent the standard SEEG-guided RF-TC procedure and were followed up after the treatment. RESULTS: Nineteen MRI-negative patients were divided into two groups based on the existence of MEG clusters; 10 patients with MEG clusters were in group I and nine patients without any MEG cluster were in group II. No significant difference was observed in terms of age, sex, type of seizures, or number of SEEG electrodes implanted. The median of the proportion of contacts in the MEG cluster was 77.0 % (IQR 57.7-100.0 %). The follow-up results showed that the probability of being seizure-free at one year after RFTC in MRI-negative patients with an MEG cluster was 30.0 % (95 % CI 11.6-77.3 %), significantly (p = 0.014) higher than that in patients without an MEG cluster; there was no significant difference when compared with MRI-positive patients. CONCLUSION: This is the first study to evaluate the value of MEG in SEEG-guided RF-TC in MRI-negative epilepsies. MEG is a useful supplement for patients with MRI-negative epilepsy. MEG can be applied in minimally invasive treatment. MEG clusters can help identify better candidates and provide a valuable target for SEEG-guided RF-TC, which leads to better outcomes.

Amygdalar and hippocampal beta rhythm synchrony during human fear memory retrieval.

BACKGROUND: Fear, as one of the basic emotions, is crucial in helping humans to perceive hazards and adapt to social activities. Clinically, fear memory is also involved in a wide spectrum of psychiatric disorders. A better understanding of the neural mechanisms of fear thereby has both neuroscientific and clinical significance. In recent years, data from animal models have demonstrated the key role of the amygdala-hippocampal circuit in the development of fear. However, the neural processing of fear memory remains unclear in humans, which is mainly due to the limitation of indirect measure of neural activity. METHODS: Herein, we investigated fear memory by direct intracranial recordings from 8 intractable epilepsy patients with depth electrodes in both the hippocampus and ipsilateral amygdala. All the patients were subjected to a well-established Pavlovian fear memory paradigm consisted of the familiarization task, conditioning task, and retrieval task, respectively. Simultaneous local field potentials from the hippocampus and amygdala were recorded during different stages. The oscillatory activities from the amygdala and hippocampus were analyzed during fear memory retrieval compared with neutral stages. RESULTS: Consistent with previous rodent studies, our results showed that the amygdala was involved in fear memory retrieval rather than neutral memory retrieval, while the hippocampus was involved both in fear memory retrieval and neutral memory retrieval. In particular, we found that there was an enhanced synchronized activity between the amygdala and hippocampus at beta frequencies (14-30 Hz), which suggested that enhanced synchronized activity at beta frequencies between the amygdala and hippocampus play a pivotal role during retrieval of fear memory in human. CONCLUSIONS: Thus, our observation that the amygdala-hippocampal system contributing to fear memory retrieval in human with frequency-depended specificity has provided new insights into the mechanism of fear and have potential clinical relevance.

Localization of Epileptogenic Zone Based on Cortico-Cortical Evoked Potential (CCEP): A Feature Extraction and Graph Theory Approach.

OBJECTIVE: Epilepsy is a chronic brain disease, which is prone to relapse and affects individuals of all ages worldwide, particularly the very young and elderly. Up to one-third of these patients are medically intractable and require resection surgery. However, the outcomes of epilepsy surgery rely upon the clear identification of epileptogenic zone (EZ). The combination of cortico-cortical evoked potential (CCEP) and electrocorticography (ECoG) provides an opportunity to observe the connectivity of human brain network and more comprehensive information that may help the clinicians localize the epileptogenic focus more precisely. However, there is no standard analysis method in the clinical application of CCEPs, especially for the quantitative analysis of abnormal connectivity of epileptic networks. The aim of this paper was to present an approach on the batch processing of CCEPs and provide information relating to the localization of EZ for clinical study. METHODS: Eight medically intractable epilepsy patients were included in this study. Each patient was implanted with subdural grid electrodes and electrical stimulations were applied directly to their cortex to induce CCEPs. After signal preprocessing, we constructed three effective brain networks at different spatial scales for each patient, regarding the amplitudes of CCEPs as the connection weights. Graph theory was then applied to analyze the brain network topology of epileptic patients, and the topological metrics of EZ and non-EZ (NEZ) were compared. RESULTS: The effective connectivity network reconstructed from CCEPs was asymmetric, both the number and the amplitudes of effective CCEPs decreased with increasing distance between stimulating and recording sites. Besides, the distribution of CCEP responses was associated with the locations of EZ which tended to have higher degree centrality (DC) and nodal shortest path length (NLP) than NEZ. CONCLUSION: Our results indicated that the brain networks of epileptics were asymmetric and mainly composed of short-distance connections. The DC and NLP were highly consistent to the distribution of the EZ, and these topological parameters have great potential to be readily applied to the clinical localization of the EZ.