Theta Oscillations Support Prefrontal-hippocampal Interactions in Sequential Working Memory / 神经科学通报·英文版

The prefrontal cortex and hippocampus may support sequential working memory beyond episodic memory and spatial navigation. This stereoelectroencephalography (SEEG) study investigated how the dorsolateral prefrontal cortex (DLPFC) interacts with the hippocampus in the online processing of sequential information. Twenty patients with epilepsy (eight women, age 27.6 ± 8.2 years) completed a line ordering task with SEEG recordings over the DLPFC and the hippocampus. Participants showed longer thinking times and more recall errors when asked to arrange random lines clockwise (random trials) than to maintain ordered lines (ordered trials) before recalling the orientation of a particular line. First, the ordering-related increase in thinking time and recall error was associated with a transient theta power increase in the hippocampus and a sustained theta power increase in the DLPFC (3-10 Hz). In particular, the hippocampal theta power increase correlated with the memory precision of line orientation. Second, theta phase coherences between the DLPFC and hippocampus were enhanced for ordering, especially for more precisely memorized lines. Third, the theta band DLPFC → hippocampus influence was selectively enhanced for ordering, especially for more precisely memorized lines. This study suggests that theta oscillations may support DLPFC-hippocampal interactions in the online processing of sequential information.

The characteristics of stereoelectroencephalography in drug-resistant epileptic spasms / 中华实用儿科临床杂志

Objective:To analyze the characteristics of stereoelectroencephalography (SEEG) in children with drug-resistant epileptic spasms (ES), and to explore the surgical strategy of children with spastic seizure under the guidance of SEEG.Methods:The clinical data of 156 children with ES who were preoperatively evaluated in the Department of Neurosurgery Ward 3, Tsinghua University Yuquan Hospital from January 2014 to December 2021 were retrospectively reviewed.All children were evaluated in the second stage of stereotactic electrode placement after a non-invasive preoperative evaluation.The characteristics of intracranial EEG, surgical strategy and prognosis were analyzed.Results:A total of 19 eligible children were included, involving 13 boys and 6 girls.The age of first onset and surgical age of them ranged 1 month to 4 years, and 2 years to 13 years, respectively.The SEEG was divided into 3 types in children with ES at the onset.Five children were SEEG type A, presenting with the focal seizure discharges at the beginning and a gradual propagation to widespread fast-wave bursts.Ten children were SEEG type B, presenting a focal leading spike followed by diffused fast-wave bursts.Four children were SEEG type C, presenting a diffuse fast wave rhythm onset.Although some electrode discharges appeared slightly " leading", they covered more than one brain region.After focal resection or thermocoagulation, 13/19 patients did not have the onset of seizures, and 5/19 and 8/19 were graded as SEEG type A, and B, respectively.During the intermittent period of SEEG attacks in children with SEEG type A and B, a significant phenomenon of focal epileptic discharge consistent with the onset of the attack was observed, and surgical removal of these areas effectively controlled spastic seizures.Conclusions:Epileptic spasms may be triggered by a focal neocortical discharge.Intracranial EEG showed that the focal seizure onset evolves into spasm or a focal " leading spike" is a good indicator of surgical prognosis.

Stereoelectroencephalography in Pediatric Epilepsy Surgery

Stereoelectroencephalography (SEEG) is an invasive technique used during the surgical management of medically refractory epilepsy. The utility of SEEG rests in its ability to survey the three-dimensional organization of the epileptogenic zone as well as nearby eloquent cortices. Once concentrated to specialized centers in Europe and Canada, the SEEG methodology has gained worldwide popularity due to its favorable morbidity profile, superior coverage of deep structures, and ability to perform multilobar explorations without the need for craniotomy. This rapid shift in practice represents both a challenge and an opportunity for pediatric neurosurgeons familiar with the subdural grid approach. The purpose of this review is to discuss the indications, technique, and safety of long-term SEEG monitoring in children. In addition to reviewing the conceptual and technical points of the diagnostic evaluation, attention will also be given to SEEG-based interventions (e.g., radiofrequency thermo-coagulation).

Application and safety of stereoelectroencephalography in invasive preoperation evaluation of drug-refractory epilepsy / 第二军医大学学报

ObjectiveTo investigate the application and safety of stereoelectroencephalography (SEEG) in invasive preoperation evaluation of drug-refractory epilepsy (DRE). MethodsWe retrospectively analyzed the clinical data of patients with DRE who underwent SEEG implantation in Shenzhen Second People's Hospital and Shenzhen University General Hospital between Aug. 2016. and Nov. 2018. The suspicious epileptogenic focus and propagation path was proposed based on the non-invasive preoperative evaluation, and then the implantation protocol of the SEEG electrodes was designed. Finally, according to the SEEG and electrical stimulation results, the resection or thermocoagulation of suspicious epileptogenic focus was done. ResultsA total of 359 electrodes were implanted in 31 DRE patients, with an average of 11.58 per patient. There were 13 electrodes (3.62%) failed to be implanted, with no additional electrode implantation. One case of intracranial hemorrhage was noted after operation, and there was no intracranial infection or cerebrospinal fluid leakage. Twenty patients received epileptogenic zone resection, 8 received epileptic network radiofrequency thermocoagulation, 1 with epileptic foci in the eloquent cortex underwent vagus nerve stimulation, and 2 received no operation. Thirty-one DRE patients were followed up for 6-30 months, with an average of (11.68±7.46) months. Of the 20 patients who underwent epileptogenic zone resection, 17 patients (85.00%, 17/20) had grade I ILAE (International League Against Epilepsy), 2 (10.00%, 2/20) had grade II, and 1 (5.00%, 1/20) had grade III. For the 8 patients undergoing epileptic network radiofrequency thermocoagulation, 6 (75.00%, 6/8) had grade IILAE and 2 (25.00%, 2/8) had grade III. There was no significant difference in outcome between the two treatments (P=0.61). For 13 patients with negative magnetic resonance imaging (MRI), 10 (76.92%, 10/13) had grade I ILAE, 2 (15.38%, 2/13) had grade II, and 1 (7.69%, 1/13) had grade III; for 15 MRI-positive patients, 13 (86.67%, 13/15) had grade I ILAE and 2 (13.33%, 2/15) had grade III. There was no significant difference in outcome between MRI-positive patients and MRI-negative patients (P=0.64). ConclusionSurgical treatment of DRE patient under the guidance of SEEG is safe and effective, and SEEG can improve the accuracy of epileptogenic foci localization, no matter in MRI positive or MRI negative patients.

Stereoelectroencephalography in Pediatric Epilepsy Surgery

Stereoelectroencephalography (SEEG) is an invasive technique used during the surgical management of medically refractory epilepsy. The utility of SEEG rests in its ability to survey the three-dimensional organization of the epileptogenic zone as well as nearby eloquent cortices. Once concentrated to specialized centers in Europe and Canada, the SEEG methodology has gained worldwide popularity due to its favorable morbidity profile, superior coverage of deep structures, and ability to perform multilobar explorations without the need for craniotomy. This rapid shift in practice represents both a challenge and an opportunity for pediatric neurosurgeons familiar with the subdural grid approach. The purpose of this review is to discuss the indications, technique, and safety of long-term SEEG monitoring in children. In addition to reviewing the conceptual and technical points of the diagnostic evaluation, attention will also be given to SEEG-based interventions (e.g., radiofrequency thermo-coagulation).

Isolated effective coherence analysis of epileptogenic networks in temporal lobe epilepsy using stereo-electroencephalography / 生物医学工程学杂志

Stereo-electroencephalography (SEEG) is widely used to record the electrical activity of patients' brain in clinical. The SEEG-based epileptogenic network can better describe the origin and the spreading of seizures, which makes it an important measure to localize epileptogenic zone (EZ). SEEG data from six patients with refractory epilepsy are used in this study. Five of them are with temporal lobe epilepsy, and the other is with extratemporal lobe epilepsy. The node outflow (out-degree) and inflow (in-degree) of information are calculated in each node of epileptic network, and the overlay between selected nodes and resected nodes is analyzed. In this study, SEEG data is transformed to bipolar montage, and then the epileptic network is established by using independent effective coherence (iCoh) method. The SEEG segments at onset, middle and termination of seizures in Delta, Theta, Alpha, Beta, and Gamma rhythms are used respectively. Finally, the K-means clustering algorithm is applied on the node values of out-degree and in-degree respectively. The nodes in the cluster with high value are compared with the resected regions. The final results show that the accuracy of selected nodes in resected region in the Delta, Alpha and Beta rhythm are 0.90, 0.88 and 0.89 based on out-degree values in temporal lobe epilepsy patients respectively, while the in-degree values cannot differentiate them. In contrast, the out-degree values are higher outside the temporal lobe in the patient with extratemporal lobe epilepsy. Based on the out-degree feature in low-frequency epileptic network, this study provides a potential quantitative measure for identifying patients with temporal lobe epilepsy in clinical.

Intracranial depth electrodes implantation in the era of image-guided surgery / A implantação de eletrodos de profundidade na era da cirurgia guiada por imagem

The advent of modern image-guided surgery has revolutionized depth electrode implantation techniques. Stereoelectroencephalography (SEEG), introduced by Talairach in the 1950s, is an invasive method for three-dimensional analysis on the epileptogenic zone based on the technique of intracranial implantation of depth electrodes. The aim of this article is to discuss the principles of SEEG and their evolution from the Talairach era to the image-guided surgery of today, along with future prospects. Although the general principles of SEEG have remained intact over the years, the implantation of depth electrodes, i.e. the surgical technique that enables this method, has undergone tremendous evolution over the last three decades, due the advent of modern imaging techniques, computer systems and new stereotactic techniques. The use of robotic systems, the constant evolution of imaging and computing techniques and the use of depth electrodes together with microdialysis probes will open up enormous prospects for applying depth electrodes and SEEG both for investigative use and for therapeutic use. Brain stimulation of deep targets and the construction of "smart" electrodes may, in the near future, increase the need to use this method.

O advento das modernas técnicas de cirurgia guiadas por imagem revolucionaram a técnica de implantação dos eletrodos de profundidade (EP). A estereoeletroencefalografia (E-EEG), conforme introduzida na década de 50 por Talairach, é um método invasivo de análise tridimensional da zona epilpeptogênica, baseado na técnica de implantação intracraniana de EP. O objetivo deste artigo é discutir os princípios da E-EEG e sua evolução, desde a era Talairach até a era atual, da cirurgia guiada por imagem, e suas perspectivas futuras. Embora os princípios gerais da E-EEG tenham permanecidos intactos ao longo dos anos, a implantação de EP, que é a técnica cirúrgica que viabiliza este método, sofreu grande evolução ao longo das últimas três décadas devido ao advento das modernas técnicas de imagem, de sistemas de computação e das novas técnicas estereotáxicas. O uso de sistemas robotizados, a evolução constante das técnicas de imagem e computação e a utilização de EP com sondas para micro diálise associados a si, abre no futuro uma enorme perspectiva para a aplicação dos EP e da E-EEG, tanto para uso investigativo como terapêutico. A estimulação cerebral de alvos profundos e a fabricação de eletrodos "inteligentes", poderão incrementar, num futuro próximo, a necessidade do uso deste método.

Estereoeletroencefalografia na era da cirurgia guiada por imagem / Stereoelectroencephalography in the era of imaging guide surgery

INTRODUÇÃO: A estereoeletroencefalografia (E-EEG), conforme introduzida na década de 50 por Talairach, é um método invasivo de análise tridimensional da zona epilpeptogênica, baseado na técnica de implantação intracraniana de eletrodos de profundidade (EP). O advento das modernas técnicas de cirurgia guiadas por imagem revolucionaram a técnica de implantação dos EP. OBJETIVO: O objetivo deste artigo é discutir os princípios da E-EEG e sua evolução, desde a era Talairach até a era atual, da cirurgia guiada por imagem, e suas perspectivas futuras. CONCLUSÕES: Embora os princípios gerais da E-EEG tenham permanecidos intactos ao longo dos anos, a implantação de EP, que é a técnica cirúrgica que viabiliza este método, sofreu uma tremenda evolução ao longo das últimas três décadas devido ao advento das modernas técnicas de imagem, de sistemas de computação e das novas técnicas estereotáxicas. O uso de sistemas robotizados, a evolução constante das técnicas de imagem e computação e a utilização de EP com sondas para micro diálise associados a si, abre no futuro uma enorme perspectiva para a aplicação dos EP e da E-EEG, tanto para uso investigativo como terapêutico. A descoberta de novos alvos, em localizações profundas e a fabricação de eletrodos "inteligentes", poderá incrementar, num futuro próximo, a necessidade do uso deste método.

INTRODUCTION: The stereoelectroencephalography (SEEG), introduced by Talairach in 50', is an invasive method of tridimensional analysis of epileptogenic zone based on the intracranial placement of depth electrodes (DE). The advent of modern imaging guided surgery had a tremendous impact in DE implantation techniques. OBJETIVE: The aim of this article is to discuss the main principles of SEEG and its evolution along the years since Talairach era until the imaging guide surgery era, with its new perspectives. CONCLUSIONS: Although the main principles of SEEG have remained intact, the placement of depth electrodes (DE) which is the surgical technique that supports this method has suffered a tremendous evolution along the last three decades due the advent of the modern imaging, the computer systems and the new stereotactic techniques. The use of robotic, the new imaging and computed systems and the use of probes of micro dialise adaptated to EP opened a tremendous perspective to DE and SEEG application as an investigative and therapeutical method. The discovery of new targets in deep brain localization and the manufacturing of "smart" DE, can increment, in a near future, the number of indications to this method.