Relationship Between Brain Activity and Impaired Consciousness in Frontal Lobe Seizures.

Background And Objectives: Impaired consciousness in epilepsy negatively affects quality of life. Previous work has focused on temporal lobe seizures, where cortical slow waves are associated with depressed subcortical arousal and impaired consciousness. However, it is unknown whether frontal lobe seizures also show cortical slow waves or a different activity pattern with impaired consciousness.

Yale Brain Atlas to interactively explore multimodal structural and functional neuroimaging data.

Understanding the relationship between structure and function in the human brain is essential for revealing how brain organization influences cognition, perception, emotion, and behavior. To this end, we introduce an interactive web tool and underlying database for Yale Brain Atlas, a high-resolution anatomical parcellation designed to facilitate precise localization and generalizable analyses of multimodal neuroimaging data. The tool supports parcel-level exploration of structural and functional data through dedicated interactive pages for each modality.

Comparison of EEG Signal Characteristics of Subdural and Depth Electrodes.

Objectives: Our study aimed to compare signal characteristics of subdural electrodes (SDE) and depth stereo EEG placed within a 5-mm vicinity in patients with drug-resistant epilepsy. We report how electrode design and placement collectively affect signal content from a shared source between these electrode types.

Methods: In subjects undergoing invasive intracranial EEG evaluation at a surgical epilepsy center from 2012 to 2018, stereo EEG and SDE electrode contacts placed within a 5-mm vicinity were identified.

Stability of infraslow correlation structure in time-shifted intracranial EEG signals.

It is increasingly understood that the epilepsies are characterized by network pathology that can span multiple spatial and temporal scales. Recent work indicates that infraslow (<0.2 Hz) envelope correlations may form a basis for distant spatial coupling in the brain.

Mapping the structure-function relationship along macroscale gradients in the human brain.

Functional coactivation between human brain regions is partly explained by white matter connections; however, how the structure-function relationship varies by function remains unclear. Here, we reference large data repositories to compute maps of structure-function correspondence across hundreds of specific functions and brain regions. We use natural language processing to accurately predict structure-function correspondence for specific functions and to identify macroscale gradients across the brain that correlate with structure-function correspondence as well as cortical thickness.

Combined neuromodulation and resection for functional cortex epilepsy: a case series.

Objective: Medically refractory epilepsy (MRE) often requires resection of the seizure onset zone (SOZ) for effective treatment. However, when the SOZ is in functional cortex (FC), achieving complete and safe resection becomes difficult, due to the seizure network overlap with function. The authors aimed to assess the safety and outcomes of a combined approach involving partial resection combined with focal neuromodulation for FC refractory epilepsy.

Optimized Multilayer Perceptron for Sensorimotor Functional Mapping Based on a Few Minutes of Intracranial Electroencephalogram Data.

Using 6-minute free-running intracranial-electroencephalogram (icEEG) during sleep, an optimized multilayer perceptron (MLP) neural network accurately maps the sensorimotor cortex (SM) and identifies the anterior lip of the central sulcus (CS) in intractable epilepsy patients. We calculated 6 performance metrics to evaluate the MLP's efficacy: accuracy, area under the curve (AUC), recall, precision, F1-scores, and specificity. Each layer had 4 neurons with hyperbolic TanH activation function and 4 with Gaussian distribution function.

Systematic 1 Hz direct electrical stimulation for seizure induction: A reliable method for localizing seizure onset zone and predicting seizure freedom.

Objective: To prospectively investigate the utility of seizure induction using systematic 1 Hz stimulation by exploring its concordance with the spontaneous seizure onset zone (SOZ) and relation to surgical outcome; comparison with seizures induced by non-systematic 50 Hz stimulation was attempted as well.

Methods: Prospective cohort study from 2018 to 2021 with ≥ 1 y post-surgery follow up at Yale New Haven Hospital. With 1 Hz, all or most of the gray matter contacts were stimulated at 1, 5, and 10 mA for 30-60s.

Functional parcellation of the cingulate gyrus by electrical cortical stimulation: a synthetic literature review and future directions.

Background: The cingulate gyrus (CG), a brain structure above the corpus callosum, is recognised as part of the limbic system and plays numerous vital roles. However, its full functional capacity is yet to be understood. In recent years, emerging evidence from imaging modalities, supported by electrical cortical stimulation (ECS) findings, has improved our understanding.

Contribution of Somatic Ras/Raf/Mitogen-Activated Protein Kinase Variants in the Hippocampus in Drug-Resistant Mesial Temporal Lobe Epilepsy.

Importance: Mesial temporal lobe epilepsy (MTLE) is the most common focal epilepsy subtype and is often refractory to antiseizure medications. While most patients with MTLE do not have pathogenic germline genetic variants, the contribution of postzygotic (ie, somatic) variants in the brain is unknown.

Objective: To test the association between pathogenic somatic variants in the hippocampus and MTLE.

Recent advances in epilepsy surgery.

Purpose Of Review: Technological innovations in the preoperative evaluation, surgical techniques and outcome prediction in epilepsy surgery have grown exponentially over the last decade. This review highlights and emphasizes relevant updates in techniques and diagnostic tools, discussing their context within standard practice at comprehensive epilepsy centres.

Recent Findings: High-resolution structural imaging has set an unprecedented opportunity to detect previously unrecognized subtle abnormalities.

Transfrontal Approach to the Amygdala for Ablation With Laser Interstitial Thermal Therapy: An Epilepsy Case Report.

Background And Importance: Stereotactic laser amygdalohippocampotomy (SLAH) using laser interstitial thermal therapy is a minimally invasive surgery used to treat mesial temporal lobe epilepsy. It uses laser probes inserted through occipital and temporo-occipital trajectories to ablate the hippocampus and amygdala. However, these trajectories are limited in their ability to ablate the superior amygdala and entorhinal cortex (ERC).

Age-dependent vestibular cingulate-cerebral network underlying gravitational perception: a cross-sectional multimodal study.

Background And Objectives: The cingulate gyrus (CG) is a frequently studied yet not wholly understood area of the human cerebrum. Previous studies have implicated CG in different adaptive cognitive-emotional functions and fascinating or debilitating symptoms. We describe an unusual loss of gravity perception/floating sensation in consecutive persons with drug-resistant epilepsy undergoing electrical cortical stimulation (ECS), network analysis, and network robustness mapping.

High-resolution cortical parcellation based on conserved brain landmarks for localization of multimodal data to the nearest centimeter.

Precise cortical brain localization presents an important challenge in the literature. Brain atlases provide data-guided parcellation based on functional and structural brain metrics, and each atlas has its own unique benefits for localization. We offer a parcellation guided by intracranial electroencephalography, a technique which has historically provided pioneering advances in our understanding of brain structure-function relationships.

The changing landscape in epilepsy imaging: Unmasking subtle and unique entities.

Dramatic changes have occurred recently in the field of epilepsy, including a fundamental shift in the etiology of epileptogenic substrates found at surgery. Hippocampal sclerosis is no longer the most common etiology found at epilepsy surgery and this decrease has been associated with an increase in the incidence of focal cortical dysplasia and encephaloceles. Significant advances have been made in molecular biology and genetics underlying the basis of malformations of cortical development, and our ability to detect epileptogenic abnormalities with MR imaging has markedly improved.

The neural networks underlying the illusion of time dilation: case study and literature survey.

This is the first known case report of a profound illusionary time dilation produced by direct electrical cortical stimulation. The patient with drug-resistant epilepsy was undergoing invasive EEG evaluation for the localization of the focus prior to resection. Stimulation of the non-dominant claustrum/insula and inferior right frontal gyrus correlated with the equivalent of a pacemaker of an internal clock in the brain.

Factors Predicting Outcome After Intracranial EEG Evaluation in Patients With Medically Refractory Epilepsy.

Background And Objectives: The aim of this study was to identify predictors of a resective surgery and subsequent seizure freedom following intracranial EEG (ICEEG) for seizure-onset localization.

Methods: This is a retrospective chart review of 178 consecutive patients with medically refractory epilepsy who underwent ICEEG monitoring from 2002 to 2015. Univariable and multivariable regression analysis identified independent predictors of resection vs other options.

Optimizing the surgical management of MRI-negative epilepsy in the neuromodulation era.

Objective: To evaluate the role of intracranial electroencephalography monitoring in diagnosing and directing the appropriate therapy for MRI-negative epilepsy and to present the surgical outcomes of patients following treatment.

Methods: Retrospective chart review between 2015-2021 at a single institution identified 48 patients with no lesion on MRI, who received surgical intervention for their epilepsy. The outcomes assessed were the surgical treatment performed and the International League Against Epilepsy seizure outcomes at 1 year of follow-up.

Passive localization of the central sulcus during sleep based on intracranial EEG.

We test the performance of a novel operator-independent EEG-based method for passive identification of the central sulcus (CS) and sensorimotor (SM) cortex. We studied seven patients with intractable epilepsy undergoing intracranial EEG (icEEG) monitoring, in whom CS localization was accomplished by standard methods. Our innovative approach takes advantage of intrinsic properties of the primary motor cortex (MC), which exhibits enhanced icEEG band-power and coherence across the CS.

Management of patients with medically intractable epilepsy and anterior temporal lobe encephaloceles.

Objective: Temporal lobe encephaloceles (TLENs) are a significant cause of medically refractory epilepsy, but there is little consensus regarding their workup and treatment. This study characterizes these lesions and their role in seizures and aims to standardize preoperative evaluation and surgical management.

Methods: Patients with TLEN who had undergone resective epilepsy surgery from December 2015 to August 2020 at a single institution were included in the study.

Tongue as a Wire? Glossokinetic Artifact and Insights From Intracranial EEG.

Background: Glossokinetic artifact (GKA) is a well-known scalp EEG artifact characterized by deflections within the delta to low-theta frequency bands and dynamic polarity typically attributed to the direction of tongue movement. This study aims to investigate intracranial EEG correlations of scalp-GKA. If the tongue is a dipole, per the conventional view, then volume-conducted deflections are expected in the nearest frontal intracranial EEG contacts.

Increased branched-chain amino acids at baseline and hours before a spontaneous seizure in the human epileptic brain.

The objective of this study was to monitor the extracellular brain chemistry dynamics at baseline and in relation to spontaneous seizures in human patients with refractory epilepsy. Thirty patients with drug-resistant focal epilepsy underwent intracranial electroencephalography and concurrent brain microdialysis for up to 8 continuous days. Extracellular brain glutamate, glutamine, and the branched-chain amino acids (BCAAs) valine, leucine, and isoleucine were quantified in the dialysis samples by liquid chromatography-tandem mass spectrometry.