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https://www.readbyqxmd.com/read/29772381/high-gamma-activity-in-the-human-hippocampus-and-parahippocampus-during-inter-trial-rest-periods-of-a-virtual-navigation-task
#1
Yi Pu, Brian R Cornwell, Douglas Cheyne, Blake W Johnson
In rodents, hippocampal cell assemblies formed during learning of a navigation task are observed to re-emerge during resting (offline) periods, accompanied by high-frequency oscillations (HFOs). This phenomenon is believed to reflect mechanisms for strengthening newly-formed memory traces. Using magnetoencephalography recordings and a beamforming source location algorithm (synthetic aperture magnetometry), we investigated high-gamma (80-140 Hz) oscillations in the hippocampal region in 18 human participants during inter-trial rest periods in a virtual navigation task...
May 14, 2018: NeuroImage
https://www.readbyqxmd.com/read/29643517/-application-of-scalp-recorded-high-frequency-oscillations-in-epileptic-encephalopathy-with-continuous-spike-and-wave-during-sleep
#2
P Gong, Z X Yang, J Xue, P Qian, H P Yang, X Y Liu, K G Bian
OBJECTIVE: To investigate the clinical significance of high-frequency oscillations (HFOs) on scalp electroencephalography (EEG) in patients with epileptic encephalopathy with continuous spike-and-wave during sleep (CSWS). METHODS: Twenty-one CSWS patients treated for epilepsy from January 2006 to December 2016 in Pediatric Department of Peking University First Hospital were enrolled into the study. Selected clinical variables including gender, age parameters, seizure frequencies and antiepileptic drugs were compared between (a)...
April 18, 2018: Beijing da Xue Xue Bao. Yi Xue Ban, Journal of Peking University. Health Sciences
https://www.readbyqxmd.com/read/29588956/high-frequency-oscillations-detected-in-ecog-recordings-correlate-with-cavernous-malformation-and-seizure-free-outcome-in-a-child-with-focal-epilepsy-a-case-report
#3
Su Liu, Michael M Quach, Daniel J Curry, Monika Ummat, Elaine Seto, Nuri F Ince
Epilepsy associated with cavernous malformation (CM) often requires surgical resection of seizure focus to achieve seizure-free outcome. High-frequency oscillations (HFOs) in intracranial electroencephalogram (EEG) are reported as potential biomarkers of epileptogenic regions, but to our knowledge there are no data on the existence of HFOs in CM-caused epilepsy. Here we report our experience of the identification of the seizure focus in a 3-year-old pediatric patient with intractable epilepsy associated with CM...
June 2017: Epilepsia Open
https://www.readbyqxmd.com/read/29577781/kurtosis-based-detection-of-intracranial-high-frequency-oscillations-for-the-identification-of-the-seizure-onset-zone
#4
Lucia Rita Quitadamo, Roberto Mai, Francesca Gozzo, Veronica Pelliccia, Francesco Cardinale, Stefano Seri
Pathological High-Frequency Oscillations (HFOs) have been recently proposed as potential biomarker of the seizure onset zone (SOZ) and have shown superior accuracy to interictal epileptiform discharges in delineating its anatomical boundaries. Characterization of HFOs is still in its infancy and this is reflected in the heterogeneity of analysis and reporting methods across studies and in clinical practice. The clinical approach to HFOs identification and quantification usually still relies on visual inspection of EEG data...
January 15, 2018: International Journal of Neural Systems
https://www.readbyqxmd.com/read/29554578/occurrence-of-thalamic-high-frequency-oscillations-in-patients-with-different-tremor-syndromes
#5
Sarah Schnitzler, Christian Johannes Hartmann, Stefan Jun Groiss, Lars Wojtecki, Alfons Schnitzler, Jan Vesper, Jan Hirschmann
OBJECTIVE: To assess whether high frequency oscillations (HFOs, >150 Hz), known to occur in basal ganglia nuclei, can be observed in the thalamus. METHODS: We recorded intraoperative local field potentials from the ventral intermediate nucleus (VIM) of the thalamus in patients with Essential Tremor (N = 16), Parkinsonian Tremor (3), Holmes Tremor (2) and Dystonic Tremor (1) during implantation of electrodes for deep brain stimulation. Recordings were performed with up to five micro/macro-electrodes that were simultaneously advanced to the stereotactic target...
February 19, 2018: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
https://www.readbyqxmd.com/read/29532041/progress-and-remaining-challenges-in-the-application-of-high-frequency-oscillations-as-biomarkers-of-epileptic-brain
#6
Fatemeh Khadjevand, Jan Cimbalnik, Gregory A Worrell
High-frequency oscillations (HFOs: 100 - 600 Hz) have been widely proposed as biomarkers of epileptic brain tissue. In addition, HFOs over a broader range of frequencies spanning 30 - 2000 Hz are potential biomarkers of both physiological and pathological brain processes. The majority of the results from humans with focal epilepsy have focused on HFOs recorded directly from the brain with intracranial EEG (iEEG) in the high gamma (65 - 100 Hz), ripple (100 - 250 Hz), and fast ripple (250 - 600 Hz) frequency ranges...
December 2017: Current Opinion in Biomedical Engineering
https://www.readbyqxmd.com/read/29508901/extrahippocampal-high-frequency-oscillations-during-epileptogenesis
#7
Lin Li, Mayur Patel, Joyel Almajano, Jerome Engel, Anatol Bragin
The current study aimed to investigate the spatial and temporal patterns of high-frequency oscillations (HFOs) in the intra-/extrahippocampal areas during epileptogenesis. Local field potentials were bilaterally recorded from hippocampus (CA1), thalamus, motor cortex, and prefrontal cortex in 13 rats before and after intrahippocampal kainic acid (KA) lesions. HFOs in the ripple (100-200 Hz) and fast ripple (250-500 Hz) ranges were detected and their rates were computed during different time periods (1-5 weeks) after KA-induced status epilepticus (SE)...
April 2018: Epilepsia
https://www.readbyqxmd.com/read/29490917/high-frequency-oscillations-in-awake-patients-undergoing-brain-tumor-related-epilepsy-surgery
#8
Anteneh M Feyissa, Gregory A Worrell, William O Tatum, Deependra Mahato, Benjamin H Brinkmann, Steven S Rosenfeld, Karim ReFaey, Perry S Bechtle, Alfredo Quinones-Hinojosa
OBJECTIVE: To examine the relationship between high-frequency oscillations (HFOs) and the presence of preoperative seizures, World Health Organization tumor grade, and isocitrate dehydrogenase 1 (IDH1) mutational status in gliomas. METHODS: We retrospectively studied intraoperative electrocorticography recorded in 16 patients with brain tumor (12 presenting with seizures) who underwent awake craniotomy and surgical resection between September 2016 and June 2017...
March 27, 2018: Neurology
https://www.readbyqxmd.com/read/29482079/on-the-origin-of-epileptic-high-frequency-oscillations-observed-on-clinical-electrodes
#9
Mohamad Shamas, Pascal Benquet, Isabelle Merlet, Mohamad Khalil, Wassim El Falou, Anca Nica, Fabrice Wendling
OBJECTIVE: In this study we aim to identify the key (patho)physiological mechanisms and biophysical factors which impact the observability and spectral features of High Frequency Oscillations (HFOs). METHODS: In order to accurately replicate HFOs we developed virtual-brain/virtual-electrode simulation environment combining novel neurophysiological models of neuronal populations with biophysical models for the source/sensor relationship. Both (patho)physiological mechanisms (synaptic transmission, depolarizing GABAA effect, hyperexcitability) and physical factors (geometry of extended cortical sources, size and position of electrodes) were taken into account...
April 2018: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
https://www.readbyqxmd.com/read/29476870/high-frequency-oscillations-in-epileptic-rodents-are-we-doing-it-right
#10
Maxime Lévesque, Siyan Wang, Jean Gotman, Massimo Avoli
BACKGROUND: The detection of high-frequency oscillations (HFOs, ripples: 80-200 Hz, fast ripples: 250-500 Hz) is often based on considering ripples or fast ripples in isolation; overlapping ripples and fast ripples are excluded from further analysis. Here, we studied overlapping HFOs during spontaneous seizures in pilocarpine-treated animals. NEW METHOD: Spontaneous seizures (n = 6 animals) presented with either hypersynchronous- (HYP, n = 18) or low-voltage fast-onset (LVF, n = 21) pattern...
April 1, 2018: Journal of Neuroscience Methods
https://www.readbyqxmd.com/read/29367441/spatial-variation-in-high-frequency-oscillation-rates-and-amplitudes-in-intracranial-eeg
#11
Hari Guragain, Jan Cimbalnik, Matt Stead, David M Groppe, Brent M Berry, Vaclav Kremen, Daniel Kenney-Jung, Jeffrey Britton, Gregory A Worrell, Benjamin H Brinkmann
OBJECTIVE: To assess the variation in baseline and seizure onset zone interictal high-frequency oscillation (HFO) rates and amplitudes across different anatomic brain regions in a large cohort of patients. METHODS: Seventy patients who had wide-bandwidth (5 kHz) intracranial EEG (iEEG) recordings during surgical evaluation for drug-resistant epilepsy between 2005 and 2014 who had high-resolution MRI and CT imaging were identified. Discrete HFOs were identified in 2-hour segments of high-quality interictal iEEG data with an automated detector...
February 20, 2018: Neurology
https://www.readbyqxmd.com/read/29366907/electrodiagnostic-applications-of-somatosensory-evoked-high-frequency-eeg-oscillations-technical-considerations
#12
A J Simpson, M O Cunningham, M R Baker
INTRODUCTION: High frequency oscillations (HFOs) embedded within the somatosensory evoked potential (SEP) are not routinely recorded/measured as part of standard clinical SEPs. However, HFOs could provide important additional diagnostic/prognostic information in various patient groups in whom SEPs are tested routinely. One area is the management of patients with hypoxic ischaemic encephalopathy (HIE) in the intensive care unit (ICU). However, the sensitivity of standard clinical SEP recording techniques for detecting HFOs is unknown...
March 2018: Brain Research Bulletin
https://www.readbyqxmd.com/read/29333618/age-associated-urethral-dysfunction-in-urethane-anesthetized-rats
#13
Ryu Kimura, Minoru Miyazato, Asuka Ashikari, Takuma Oshiro, Seiichi Saito
AIMS: We aimed to investigate the age-associated changes in movement coordination between the urinary bladder and the urethra in rats. METHODS: A total of 17 female Sprague-Dawley rats were used. The rats were divided into young (3 months old) and middle-aged (12-15 months old) groups. In both groups, isovolumetric cystometry and urethral perfusion pressure (UPP) measurements were performed under urethane anesthesia. After the rhythmic bladder contractions stabilized, L-arginine, a nitric oxide (NO) substrate (100 mg/kg), was administered intravenously in both groups...
January 15, 2018: Neurourology and Urodynamics
https://www.readbyqxmd.com/read/29315516/strong-coupling-between-slow-oscillations-and-wide-fast-ripples-in-children-with-epileptic-spasms-investigation-of-modulation-index-and-occurrence-rate
#14
Yasushi Iimura, Kevin Jones, Lynne Takada, Itsuki Shimizu, Misaki Koyama, Kyoko Hattori, Yushi Okazawa, Yutaka Nonoda, Eishi Asano, Tomoyuki Akiyama, Cristina Go, Ayako Ochi, O Carter Snead, Elizabeth J Donner, James T Rutka, James M Drake, Hiroshi Otsubo
OBJECTIVE: Epileptic spasms (ES) often become drug-resistant. To reveal the electrophysiological difference between children with ES (ES+) and without ES (ES-), we compared the occurrence rate (OR) of high-frequency oscillations (HFOs) and the modulation index (MI) of coupling between slow and fast oscillations. In ES+, we hypothesized that (1) pathological HFOs are more widely distributed and (2) slow oscillations show stronger coupling with pathological HFOs than in ES-. METHODS: We retrospectively reviewed 24 children with drug-resistant multilobar onset epilepsy, who underwent intracranial video electroencephalography prior to multilobar resections...
March 2018: Epilepsia
https://www.readbyqxmd.com/read/29288992/the-effect-of-increased-intracranial-eeg-sampling-rates-in-clinical-practice
#15
Kathryn A Davis, Seth P Devries, Abba Krieger, Temenuzhka Mihaylova, Daniela Minecan, Brian Litt, Joost B Wagenaar, William C Stacey
OBJECTIVE: Recent research suggests that high frequency intracranial EEG (iEEG) may improve localization of epileptic networks. This study aims to determine whether recording macroelectrode iEEG with higher sampling rates improves seizure localization in clinical practice. METHODS: 14 iEEG seizures from 10 patients recorded with >2000 Hz sampling rate were downsampled to four sampling rates: 100, 200, 500, 1000 Hz. In the 56 seizures, seizure onset time and location was marked by 5 independent, blinded EEG experts...
November 16, 2017: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
https://www.readbyqxmd.com/read/29244226/high-frequency-oscillations-are-not-better-biomarkers-of-epileptogenic-tissues-than-spikes
#16
Nicolas Roehri, Francesca Pizzo, Stanislas Lagarde, Isabelle Lambert, Anca Nica, Aileen McGonigal, Bernard Giusiano, Fabrice Bartolomei, Christian-George Bénar
OBJECTIVE: High-frequency oscillations (HFOs) in intracerebral EEG (stereoelectroencephalography; SEEG) are considered as better biomarkers of epileptogenic tissues than spikes. How this can be applied at the patient level remains poorly understood. We investigated how well HFOs and spikes can predict epileptogenic regions with a large spatial sampling at the patient level. METHODS: We analyzed non-REM sleep SEEG recordings sampled at 2,048Hz of 30 patients. Ripples (Rs; 80-250Hz), fast ripples (FRs; 250-500Hz), and spikes were automatically detected...
January 2018: Annals of Neurology
https://www.readbyqxmd.com/read/29175154/immature-status-epilepticus-in-vitro-models-reveal-differences-in-cholinergic-control-and-hfo-properties-of-adult-ca3-interictal-discharges-in-temporal-vs-septal-hippocampus
#17
Apostolos Mikroulis, Christos Panagiotis Lisgaras, Caterina Psarropoulou
We have earlier demonstrated that a Status Epilepticus (SE) during CNS development has long-lasting effects on cholinergic neurotransmission, detectable in vitro and in vivo. In this work, we aimed to localize changes in temporal (T) vs septal (S) hippocampus and to correlate adult CA3 interictal epileptiform discharge (IED) frequency changes to those of Ripples (R) and Fast Ripples (FR) of the High-Frequency Oscillations (HFOs). Spontaneous IEDs were induced by bathing slices in Mg2+ -free ACSF or in 4-Aminopyridine (4-AP, 50 µM) and data were analyzed separately for each model...
January 15, 2018: Neuroscience
https://www.readbyqxmd.com/read/29111591/magnetoencephalographic-imaging-of-ictal-high-frequency-oscillations-80-200-hz-in-pharmacologically-resistant-focal-epilepsy
#18
Jayabal Velmurugan, Srikantan S Nagarajan, Narayanan Mariyappa, Shankar G Ravi, Kandavel Thennarasu, Ravindranadh C Mundlamuri, Kenchaiah Raghavendra, Rose Dawn Bharath, Jitender Saini, Arimappamagan Arivazhagan, Jamuna Rajan, Anita Mahadevan, Malla B Rao, Parthasarathy Satishchandra, Sanjib Sinha
OBJECTIVE: Specificity of ictal high-frequency oscillations (HFOs) in identifying epileptogenic abnormality is significant, compared to the spikes and interictal HFOs. The objectives of the study were to detect and to localize ictal HFOs by magnetoencephalography (MEG) for identifying the seizure onset zone (SOZ), evaluate the cortical excitability from preictal to ictal transition, and establish HFO concordance rates with other modalities and postsurgical resection. METHODS: Sixty-seven patients with drug-resistant epilepsy had at least 1 spontaneous seizure each during MEG acquisition, and analysis was carried out on 20 seizures from 20 patients...
January 2018: Epilepsia
https://www.readbyqxmd.com/read/29093566/hypertension-induces-additional-cardiometabolic-impairments-and-attenuates-aerobic-exercise-training-adaptations-in-fructose-fed-ovariectomized-rats
#19
Janaina de O Brito-Monzani, Iris Callado Sanches, Nathalia Bernardes, Kátia Ponciano, Ivana C Moraes-Silva, Maria-Cláudia Irigoyen, Susana Llesuy, Kátia De Angelis
We tested whether hypertension favors the development of additional cardiometabolic changes in fructose-fed ovariectomized rats and how it affects aerobic exercise training (ET) effects. All rats received fructose in drinking water (10%) beginning at weaning, were ovariectomized at 10 weeks of age and divided into the normotensive sedentary (NFOS) and trained (NFOT) and hypertensive sedentary (HFOS) and trained (HFOT) groups. ET was performed on a treadmill. Arterial pressure (AP) was directly recorded; heart rate and AP variabilities were analyzed...
February 2018: Hypertension Research: Official Journal of the Japanese Society of Hypertension
https://www.readbyqxmd.com/read/29062105/resection-of-high-frequency-oscillations-predicts-seizure-outcome-in-the-individual-patient
#20
Tommaso Fedele, Sergey Burnos, Ece Boran, Niklaus Krayenbühl, Peter Hilfiker, Thomas Grunwald, Johannes Sarnthein
High frequency oscillations (HFOs) are recognized as biomarkers for epileptogenic brain tissue. A remaining challenge for epilepsy surgery is the prospective classification of tissue sampled by individual electrode contacts. We analysed long-term invasive recordings of 20 consecutive patients who subsequently underwent epilepsy surgery. HFOs were defined prospectively by a previously validated, automated algorithm in the ripple (80-250 Hz) and the fast ripple (FR, 250-500 Hz) frequency band. Contacts with the highest rate of ripples co-occurring with FR over several five-minute time intervals designated the HFO area...
October 23, 2017: Scientific Reports
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