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depth electrodes

Oriol Blázquez, Gemma Martín, Ivan Camps, Antonio Mariscal, Julian López-Vidrier, Joan Manel Ramirez, Sergi Hernández, Sonia Estrade, Francesca Peiro, Rosalía Serna, Blas Garrido
The resistive switching properties of silicon-aluminium oxynitride (SiAlON) based devices have been studied. Electrical transport mechanisms at both resistance states were determined, exhibiting an ohmic behaviour at low resistant state and a defect-related Poole-Frenkel mechanism at high resistant state. Nevertheless, some features on the Al top-electrode are generated during the initial electroforming, suggesting some material modifications. An in-depth microscopic study at the nanoscale have been performed after the electroforming process, by acquiring scanning electron microscopy and transmission electron microscopy images...
March 16, 2018: Nanotechnology
Gopalakrishnan M Sasidharan
Epidermoid cysts are notorious for their propensity to sneak into deep recesses between cranial nerves in the posterior fossa. Attempts to achieve complete excision using ordinary instruments when tempted by the seeming ease of dissection is known to cause unacceptable deficits. The Xomed monopolar stimulator electrode probe of the nerve integrity electromyography monitor has several advantages when used as the primary dissection tool for deep-seated epidermoid cysts. Cerebellopontine angle epidermoid is the classical prototype of a strategically placed deep-seated epidermoid tumor...
January 12, 2018: Curēus
Roey Schurr, Mor Nitzan, Ruth Eliahou, Laurent Spinelli, Margitta Seeck, Olaf Blanke, Shahar Arzy
In mental time travel (MTT) one is "traveling" back-and-forth in time, remembering, and imagining events. Despite intensive research regarding memory processes in the hippocampus, it was only recently shown that the hippocampus plays an essential role in encoding the temporal order of events remembered, and therefore plays an important role in MTT. Does it also encode the temporal relations of these events to the remembering self? We asked patients undergoing pre-surgical evaluation with depth electrodes penetrating the temporal lobes bilaterally toward the hippocampus to project themselves in time to a past, future, or present time-point, and then make judgments regarding various events...
2018: Frontiers in Computational Neuroscience
Alfredo Mirandola, Giuseppe Magro, Marco Lavagno, Andrea Mairani, Silvia Molinelli, Stefania Russo, Edoardo Mastella, Alessandro Vai, Davide Maestri, Vanessa La Rosa, Mario Ciocca
PURPOSE: To dosimetrically characterize a multi-layer ionization chamber (MLIC) prototype for quality assurance (QA) of pristine integral ionization curves (ICs) and spread-out-Bragg-peaks (SOBPs) for scanning light ion beams. METHODS: QUBE (De.Tec.Tor., Torino, Italy) is a modular detector designed for QA in particle therapy (PT). Its main module is a MLIC detector, able to evaluate particle beam relative depth ionization distributions at different beam energies and modulations...
March 14, 2018: Medical Physics
Firas Bannout, Sheri Harder, Michael Lee, Alexander Zouros, Ravi Raghavan, Travis Fogel, Kenneth De Los Reyes, Travis Losey
The neurosurgical treatment of skull base temporal encephalocele for patients with epilepsy is variable. We describe two adult cases of temporal lobe epilepsy (TLE) with spheno-temporal encephalocele, currently seizure-free for more than two years after anterior temporal lobectomy (ATL) and lesionectomy sparing the hippocampus without long-term intracranial electroencephalogram (EEG) monitoring. Encephaloceles were detected by magnetic resonance imaging (MRI) and confirmed by maxillofacial head computed tomography (CT) scans...
March 12, 2018: Brain Sciences
Felix J Berger, Thomas M Higgins, Marcel Rother, Arko Graf, Yuriy Zakharko, Sybille Allard, Maik Matthiesen, Jan M Gotthardt, Ullrich Scherf, Jana Zaumseil
Dense layers of semiconducting single-walled carbon nanotubes (SWNTs) serve as electrochromic materials in the near-infrared with high optical density and high conductivity. Electrochromic cells with tunable notch filter properties instead of broadband absorption are created via highly selective dispersion of specific semiconducting SWNTs through polymer-wrapping followed by deposition of thick films by aerosol-jet printing. A simple planar geometry with spray-coated mixed SWNTs as the counter electrode renders transparent metal oxides redundant and facilitates complete bleaching within a few seconds through iongel electrolytes with high ionic conductivities...
March 9, 2018: ACS Applied Materials & Interfaces
Qing Zhao, Weiwei Huang, Zhiqiang Luo, Luojia Liu, Yong Lu, Yixin Li, Lin Li, Jinyan Hu, Hua Ma, Jun Chen
Quinones, which are ubiquitous in nature, can act as sustainable and green electrode materials but face dissolution in organic electrolytes, resulting in fast fading of capacity and short cycle life. We report that quinone electrodes, especially calix[4]quinone (C4Q) in rechargeable metal zinc batteries coupled with a cation-selective membrane using an aqueous electrolyte, exhibit a high capacity of 335 mA h g-1 with an energy efficiency of 93% at 20 mA g-1 and a long life of 1000 cycles with a capacity retention of 87% at 500 mA g-1 ...
March 2018: Science Advances
Josef Parvizi, Sabine Kastner
Intracranial electroencephalography (iEEG), also known as electrocorticography when using subdural grid electrodes or stereotactic EEG when using depth electrodes, is blossoming in various fields of human neuroscience. In this article, we highlight the potentials of iEEG in exploring functions of the human brain while also considering its limitations. The iEEG signal provides anatomically precise information about the selective engagement of neuronal populations at the millimeter scale and the temporal dynamics of their engagement at the millisecond scale...
March 5, 2018: Nature Neuroscience
Anna Witkowska-Wrobel, Kirill Aristovich, Mayo Faulkner, James Avery, David Holder
Imaging ictal and interictal activity with Electrical Impedance Tomography (EIT) using intracranial electrode mats has been demonstrated in animal models of epilepsy. In human epilepsy subjects undergoing presurgical evaluation, depth electrodes are often preferred. The purpose of this work was to evaluate the feasibility of using EIT to localise epileptogenic areas with intracranial electrodes in humans. The accuracy of localisation of the ictal onset zone was evaluated in computer simulations using 9M element FEM models derived from three subjects...
February 27, 2018: NeuroImage
Naif H Al-Hardan, Muhammad Azmi Abdul Hamid, Roslinda Shamsudin, Ensaf Mohammed Al-Khalqi, Lim Kar Keng, Naser M Ahmed
Macroporous silicon was prepared through an anodization process; the prepared samples showed an average pore size ranging from 4 to 6 microns, and the depth of the pores in the silicon wafer was approximately 80 microns. The prepared samples were tested for hydrogen peroxide (H₂O₂) concentrations, which can be used for industrial and environmental sensing applications. The selected H₂O₂ concentration covered a wide range from 10 to 5000 μM. The tested samples showed a linear response through the tested H₂O₂ concentrations with a sensitivity of 0...
February 28, 2018: Sensors
Adam J Kundishora, Dario J Englot, Philip A Starr, Alastair J Martin, Paul S Larson
BACKGROUND/AIMS: Interventional MRI (iMRI) allows real-time confirmation of electrode and microcatheter location in anesthetized patients; however, MRI-compatible pneumatic compression devices (PCD) to reduce the periprocedural venous thromboembolism (VTE) risk are not commercially available. Given the paucity of literature on VTE following iMRI surgery, better characterizing patients suffering this complication and the incidence of this event following iMRI procedures is pivotal for defining best surgical practices...
March 1, 2018: Stereotactic and Functional Neurosurgery
W S Konerding, U P Froriep, A Kral, P Baumhoff
In neuroscience, single-shank penetrating multi-electrode arrays are standard for sequentially sampling several cortical sites with high spatial and temporal resolution, with the disadvantage of neuronal damage. Non-penetrating surface grids used in electrocorticography (ECoG) permit simultaneous recording of multiple cortical sites, with limited spatial resolution, due to distance to neuronal tissue, large contact size and high impedances. Here we compared new thin-film parylene C ECoG grids, covering the guinea pig primary auditory cortex, with simultaneous recordings from penetrating electrode array (PEAs), inserted through openings in the grid material...
February 28, 2018: Scientific Reports
Ali Firouzi, Ruimin Qiao, Shahrokh Motallebi, Christian W Valencia, Hannah S Israel, Mai Fujimoto, L Andrew Wray, Yi-De Chuang, Wanli Yang, Colin D Wessells
The demand of sustainable power supply requires high-performance cost-effective energy storage technologies. Here we report a high-rate long-life low-cost sodium-ion battery full-cell system by innovating both the anode and the electrolyte. The redox couple of manganese(I/II) in Prussian blue analogs enables a high-rate and stable anode. Soft X-ray absorption spectroscopy and resonant inelastic X-ray scattering provide direct evidence suggesting the existence of monovalent manganese in the charged anode. There is a strong hybridization between cyano ligands and manganese-3d states, which benefits the electronic property for improving rate performance...
February 28, 2018: Nature Communications
Hank Bink, Madineh Sedigh-Sarvestani, Ivan Fernandez-Lamo, Lohith Kini, Hoameng Ung, Duygu Kuzum, Flavia Vitale, Brian Litt, Diego Contreras
New devices that use targeted electrical stimulation to treat refractory localization-related epilepsy have shown great promise, though it is not well known which targets most effectively prevent the initiation and spread of seizures. To better understand how the brain transitions from healthy to seizing on a local scale, we induced focal epileptiform activity in the visual cortex of five anesthetized cats with local application of the GABAA blocker picrotoxin while simultaneously recording local field potentials on a high-resolution electrocorticography array and laminar depth probes...
February 28, 2018: Journal of Neurophysiology
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...
February 11, 2018: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
Bruno Rossion, Corentin Jacques, Jacques Jonas
The neural basis of face categorization has been widely investigated with functional magnetic resonance imaging (fMRI), identifying a set of face-selective local regions in the ventral occipitotemporal cortex (VOTC). However, indirect recording of neural activity with fMRI is associated with large fluctuations of signal across regions, often underestimating face-selective responses in the anterior VOTC. While direct recording of neural activity with subdural grids of electrodes (electrocorticography, ECoG) or depth electrodes (stereotactic electroencephalography, SEEG) offers a unique opportunity to fill this gap in knowledge, these studies rather reveal widely distributed face-selective responses...
February 26, 2018: Annals of the New York Academy of Sciences
Richárd Fiáth, Katharina T Hofer, Vivien Csikós, Domonkos Horváth, Tibor Nánási, Kinga Tóth, Frederick Pothof, Christian Böhler, Maria Asplund, Patrick Ruther, István Ulbert
Stereo-electroencephalography depth electrodes, regularly implanted into drug-resistant patients with focal epilepsy to localize the epileptic focus, have a low channel count (6-12 macro- or microelectrodes), limited spatial resolution (0.5-1 cm) and large contact area of the recording sites (~mm2). Thus, they are not suited for high-density local field potential and multiunit recordings. In this paper, we evaluated the long-term electrophysiological recording performance and histocompatibility of a neural interface consisting of 32 microelectrodes providing a physical shape similar to clinical devices...
February 26, 2018: Biomedizinische Technik. Biomedical Engineering
Marlene Derner, Amirhossein Jahanbekam, Christian Bauckhage, Nikolai Axmacher, Juergen Fell
Absolute (i.e. measured) rhinal and hippocampal phase values are predictive for memory formation. It has been an open question, whether the capability of mediotemporal structures to react to stimulus presentation with phase shifts may be similarly indicative of successful memory formation. We analyzed data from 27 epilepsy patients implanted with depth electrodes in the hippocampus and entorhinal cortex, who performed a continuous word recognition task. Electroencephalographic (EEG) phase information related to the first presentation of repeatedly presented words was used for prediction of subsequent remembering versus forgetting applying a support vector machine...
February 23, 2018: European Journal of Neuroscience
H Jia, R Torres, Y Nguyen, D De Seta, E Ferrary, H Wu, O Sterkers, D Bernardeschi, I Mosnier
BACKGROUND AND PURPOSE: Intraoperative conebeam CT has been introduced into the operating room and provides quick radiologic feedback. This study aimed to investigate its utility in the assessment of the positioning of the electrode array after cochlear implantation. MATERIALS AND METHODS: This was a retrospective study of 51 patients (65 ears) with intraoperative imaging by conebeam CT (O-arm) after cochlear implantation between 2013 and 2017. Correct placement into the cochlea was immediately identified...
February 22, 2018: AJNR. American Journal of Neuroradiology
Wenting Dang, Libu Manjakkal, William Taube Navaraj, Leandro Lorenzelli, Vincenzo Vinciguerra, Ravinder Dahiya
Sensor-laden wearable systems that are capable of providing continuous measurement of key physiological parameters coupled with data storage, drug delivery and feedback therapy have attracted huge interest. Here we report a stretchable wireless system for sweat pH monitoring, which is able to withstand up to 53% uniaxial strain and more than 500 cycles to 30% strain. The stretchability of the pH sensor patch is provided by a pair of serpentine-shaped stretchable interconnects. The pH sensing electrode is made of graphite-polyurethane composite, which is suitable for biosensor application...
June 1, 2018: Biosensors & Bioelectronics
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