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Depth electrode

Amirali Toossi, Dirk G Everaert, Peter Seres, Jacob L Jaremko, Kevin Robinson, C Chris Kao, Peter E Konrad, Vivian K Mushahwar
OBJECTIVE The overall goal of this study was to develop an image-guided spinal stereotactic setup for intraoperative intraspinal microstimulation (ISMS). System requirements were as follows: 1) ability to place implants in various segments of the spinal cord, targeting the gray matter with a < 0.5-mm error; 2) modularity; and 3) compatibility with standard surgical tools. METHODS A spine-mounted stereotactic system was developed, optimized, and tested in pigs. The system consists of a platform supporting a micromanipulator with 6 degrees of freedom...
June 15, 2018: Journal of Neurosurgery. Spine
Jason S Naftulin, Omar J Ahmed, Giovanni Piantoni, Jean-Baptiste Eichenlaub, Louis-Emmanuel Martinet, Mark A Kramer, Sydney S Cash
OBJECTIVE: The treatment of focal epilepsies is largely predicated on the concept that there is a "focus" from which the seizure emanates. Yet, the physiological context that determines if and how ictal activity starts and propagates remains poorly understood. To delineate these phenomena more completely, we studied activity outside the seizure-onset zone prior to and during seizure initiation. METHODS: Stereotactic depth electrodes were implanted in 17 patients with longstanding pharmacoresistant epilepsy for lateralization and localization of the seizure-onset zone...
June 13, 2018: Epilepsia
Geerte G J Ramakers, Gijsbert A van Zanten, Hans G X M Thomeer, Robert J Stokroos, Martijn W Heymans, Inge Stegeman
OBJECTIVE: To develop and internally validate a prediction model for tinnitus recovery following unilateral cochlear implantation. DESIGN: A cross-sectional retrospective study. SETTING: A questionnaire concerning tinnitus was sent to patients with bilateral severe to profound hearing loss, who underwent unilateral cochlear implantation at the University Medical Center Utrecht, the Netherlands, between 1 January 2006 and 31 December 2015. PARTICIPANTS: Of 137 included patients, 87 patients experienced tinnitus preoperatively...
June 11, 2018: BMJ Open
Rodrigo Bainy Leal, Mark William Lopes, Douglas Affonso Formolo, Cristiane Ribeiro de Carvalho, Alexandre Ademar Hoeller, Alexandra Latini, Daniel Santos Sousa, Peter Wolf, Rui Daniel Prediger, Zuner Assis Bortolotto, Marcelo Neves Linhares, Kátia Lin, Roger Walz
Fear is a conscious state caused by exposure to real or imagined threats that trigger stress responses that affect the body and brain, particularly limbic structures. A sub-group of patients with mesial temporal lobe epilepsy related to hippocampus sclerosis (MTLE-HS) have seizures with fear, which is called ictal fear (IF), due to epileptic activity within the brain defensive survival circuit structures. Synaptic transmission efficacy can be bi-directionally modified through potentiation (long-term potentiation (LTP)) or depression (long-term depression (LTD)) as well as the phosphorylation state of Ser831 and Ser845 sites at the GluA1 subunit of the glutamate AMPA receptors, which has been characterized as a critical event for this synaptic plasticity...
June 7, 2018: Molecular Psychiatry
Junjun Zhang, Li-Bing Lv, Tian-Jian Zhao, Yun-Xiao Lin, Qiu-Ying Yu, Juan Su, Shin-Ichi Hirano, Xin-Hao Li, Jie-Sheng Chen
Electrochemical gas evolution and activation reactions are complicated processes, involving not only active electrocatalysts but also the interaction among solid electrodes, electrolyte and gas-phase products/reactants. Herein, we described the control of multi-phase interfaces of super-adsorbing graphene-based electrodes without changing the active centers to significantly facilitate mass diffusion kinetics for superior performance. The achieved in-depth understanding on the way to regulate the interfacial properties for generally promoted electrochemical performance could provide valuable clues for electrode manufacture from the other aspect of the design of more active electrocatalysts...
May 30, 2018: ChemSusChem
S Fiocchi, E Chiaramello, P Ravazzani, M Parazzini
In the last two decades, motor cortex stimulation has been recognized as a valuable alternative to pharmacological therapy for the treatment of neuropathic pain. Although this technique started to be used in clinical studies, the debate about the optimal settings that enhance its effectiveness without inducing tissue damage is still open. To this purpose, computational approaches applied to realistic human models aimed to assess the current density distribution within the cortex can be a powerful tool to provide a basic understanding of that technique and could help the design of clinical experimental protocols...
2018: Computational and Mathematical Methods in Medicine
Giulia Liberati, Maxime Algoet, Anne Klöcker, Susana Ferrao Santos, Jose Geraldo Ribeiro-Vaz, Christian Raftopoulos, André Mouraux
Salient nociceptive and non-nociceptive stimuli elicit low-frequency local field potentials (LFPs) in the human insula. Nociceptive stimuli also elicit insular gamma-band oscillations (GBOs), possibly preferential for thermonociception, which have been suggested to reflect the intensity of perceived pain. To shed light on the functional significance of these two responses, we investigated whether they would be modulated by stimulation intensity and temporal expectation - two factors contributing to stimulus saliency...
May 29, 2018: Scientific Reports
Luke J Heales, Kylie Tucker, Bill Vicenzino, Paul W Hodges, David A MacDonald
INTRODUCTION: Intramuscular electromyography electrodes targeting flexor digitorum profundus (FDP) are inserted via the anterior or medial aspect of the forearm. These two methods pose different risks to neurovascular structures which overly FDP. This study aimed to compare the insertion depth and consider advantages and limitations of two different techniques to insert intramuscular electrodes into FDP. METHODS: Using ultrasound imaging, neurovascular structures were identified along the path of FDP electrode insertion at the junction of the proximal and middle third of the ulna, bilaterally, in ten healthy individuals...
May 22, 2018: Journal of Electromyography and Kinesiology
Haoran Ding, Jian Zhou, Yuguang Guan, Feng Zhai, Mengyang Wang, Jing Wang, Guoming Luang
OBJECTIVE: The diagnosis and treatment of insular and insulo-opercular epilepsy remain underexplored because the insula is covered by the insulo-opercular and a dense vascular curtain. Stereoelectro-encephalography (SEEG) is a reliable and recommended technique for locating the epileptic zone, especially in insular and insulo-opercular regions (Isnard et al., 2000, 2004). Bipolar electro-coagulation with cortextomy is an alternative therapy for treating drug-resistant epilepsy and is more convenient and less likely to cause adverse complications...
May 24, 2018: Epilepsy Research
Yasunori Nagahama, Alan J Schmitt, Daichi Nakagawa, Adam S Vesole, Janina Kamm, Christopher K Kovach, David Hasan, Mark Granner, Brian J Dlouhy, Matthew A Howard, Hiroto Kawasaki
OBJECTIVE Intracranial electroencephalography (iEEG) provides valuable information that guides clinical decision-making in patients undergoing epilepsy surgery, but it carries technical challenges and risks. The technical approaches used and reported rates of complications vary across institutions and evolve over time with increasing experience. In this report, the authors describe the strategy at the University of Iowa using both surface and depth electrodes and analyze outcomes and complications. METHODS The authors performed a retrospective review and analysis of all patients who underwent craniotomy and electrode implantation from January 2006 through December 2015 at the University of Iowa Hospitals and Clinics...
May 25, 2018: Journal of Neurosurgery
Aarno Dietz, Matti Iso-Mustajärvi, Sini Sipari, Jyrki Tervaniemi, Dzemal Gazibegovic
PURPOSE: To evaluate the insertion characteristics and trauma of a new slim lateral wall electrode (SlimJ) in human temporal bones (TB). METHODS: Pre- and postoperative assessment was performed using cone beam computed tomography (CBCT) and image fusion in 11 human TB. The position of the array in each cochlea was analyzed and described using a vertical scaling factor, calculated by dividing the distance of the scala tympani floor to the centre of the electrode by the duct height...
May 24, 2018: European Archives of Oto-rhino-laryngology
Robert A McGovern, Soha Alomar, William E Bingaman, Jorge Gonzalez-Martinez
BACKGROUND: The management of medically refractory epilepsy patients who are not surgical candidates has remained challenging. Closed loop-or responsive-neurostimulation (RNS) is now an established therapy for the treatment of epilepsy with specific indications. The RNS® system (NeuroPace Inc, Mountainview, California) has recently been shown to be effective in reducing the seizure frequency of partial onset seizures. The electrode design consists of either intracerebral depth electrodes or subdural strip electrodes, and stereotaxis is typically used to guide placement into the EZ...
May 23, 2018: Operative Neurosurgery (Hagerstown, Md.)
Pavel Mistrík, Claude Jolly, Daniel Sieber, Ingeborg Hochmair
Objective: A design comparison of current perimodiolar and lateral wall electrode arrays of the cochlear implant (CI) is provided. The focus is on functional features such as acoustic frequency coverage and tonotopic mapping, battery consumption and dynamic range. A traumacity of their insertion is also evaluated. Methods: Review of up-to-date literature. Results: Perimodiolar electrode arrays are positioned in the basal turn of the cochlea near the modiolus...
December 2017: World Journal of Otorhinolaryngology—Head and Neck Surgery
Ville Jäntti, Tuomo Ylinen, Narayan Puthanmadam Subramaniyam, Kotoe Kamata, Arvi Yli-Hankala, Pasi Kauppinen, Eila Sonkajärvi
Purpose - Anesthesiologists have increasingly started to use EEG based indexes to estimate the level and type of unconsciousness. However, the physiology and biophysics are poorly understood in anesthesiological literature. Methods - EEG was recorded from electrodes on the surface of head, including scalp, as well as DBS (deep brain stimulation) electrodes implanted deep in the brain. Mathematical modeling with a realistic head model was performed to create illustrative images of the sensitivity of electrode montages...
May 18, 2018: International Journal of Radiation Biology
John A Thompson, Salam Oukal, Hagai Bergman, Steven Ojemann, Adam O Hebb, Sara Hanrahan, Zvi Israel, Aviva Abosch
OBJECTIVE Deep brain stimulation (DBS) of the subthalamic nucleus (STN) has become standard care for the surgical treatment of Parkinson's disease (PD). Reliable interpretation of microelectrode recording (MER) data, used to guide DBS implantation surgery, requires expert electrophysiological evaluation. Recent efforts have endeavored to use electrophysiological signals for automatic detection of relevant brain structures and optimal implant target location. The authors conducted an observational case-control study to evaluate a software package implemented on an electrophysiological recording system to provide online objective estimates for entry into and exit from the STN...
May 18, 2018: Journal of Neurosurgery
Fangyuan Zhao, Steffen Hardt, Volker Hartmann, Huijie Zhang, Marc M Nowaczyk, Matthias Rögner, Nicolas Plumeré, Wolfgang Schuhmann, Felipe Conzuelo
Interfacing photosynthetic proteins specifically photosystem 1 (PS1) with electrodes enables light-induced charge separation processes for powering semiartificial photobiodevices with, however, limited long-term stability. Here, we present the in-depth evaluation of a PS1/Os-complex-modified redox polymer-based biocathode by means of scanning photoelectrochemical microscopy. Focalized local illumination of the bioelectrode and concomitant collection of H2 O2 at the closely positioned microelectrode provide evidence for the formation of partially reduced oxygen species under light conditions...
May 17, 2018: Nature Communications
Kimford J Meador, Casey H Halpern, Bruce P Hermann
Two recent articles in Epilepsia have raised concerns about adverse cognitive effects associated with intracranial electrode implantation. However, both studies have important limitations, and their results contrast with studies that report no adverse cognitive effects of intracranial electrodes for diagnosis or neurostimulation in epilepsy. Furthermore, no data are provided on the relative safety of depth electrodes implanted along the longitudinal axis of the hippocampus vs other electrode locations or types of electrodes...
May 17, 2018: Epilepsia
Nele Vandersickel, Alexandre Bossu, Jan De Neve, Albert Dunnink, Veronique M F Meijborg, Marcel A G van der Heyden, Jet D M Beekman, Jacques M T De Bakker, Marc A Vos, Alexander V Panfilov
OBJECTIVES: This study investigated the arrhythmogenic mechanisms responsible for torsade de pointes (TdP) in the chronic atrioventricular block dog model, known for its high susceptibility for TdP. BACKGROUND: The mechanism of TdP arrhythmias has been under debate for many years. Focal activity as well as re-entry have both been mentioned in the initiation and the perpetuation of TdP. METHODS: In 5 TdP-sensitive chronic atrioventricular block dogs, 56 needle electrodes were evenly distributed transmurally to record 240 unipolar local electrograms simultaneously...
December 26, 2017: JACC. Clinical Electrophysiology
Xuehong Zhou, Wenqiang Zhang, Cong Wang, Jiadong Zhou, Linlin Liu, Zengqi Xie, Yuguang Ma
Ion-doped states are significant for improving the performance in organic semiconductor-based devices, which require clear characterization to understand their relationship with conductivity and charge transporting mechanisms. In this paper, Raman spectroscopy is used to track the evolution of a dianion-anion-neutral mixture in a perylene bisimide (PBI)-doped film under air, with z-scanning carried out in the confocal mode. The precise distribution for the different states along the film depth is realized within 3...
April 27, 2018: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Mayo Faulkner, Sana Hannan, Kirill Aristovich, James Avery, David Holder
Electrical Impedance Tomography (EIT) is an emerging technique which has been used to image evoked activity during whisker displacement in the cortex of an anaesthetised rat with a spatiotemporal resolution of 200 μm and 2 ms. The aim of this work was to extend EIT to image not only from the cortex but also from deeper structures active in somatosensory processing, specifically the ventral posterolateral (VPL) nucleus of the thalamus. The direct response in the cortex and VPL following 2 Hz forepaw stimulation were quantified using a 57-channel epicortical electrode array and a 16-channel depth electrode...
May 9, 2018: NeuroImage
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