keyword
MENU ▼
Read by QxMD icon Read
search

Multi-electrode array

keyword
https://www.readbyqxmd.com/read/28092575/a-cmos-current-steering-neurostimulation-array-with-integrated-dac-calibration-and-charge-balancing
#1
Elliot Greenwald, Christoph Maier, Qihong Wang, Robert Beaulieu, Ralph Etienne-Cummings, Gert Cauwenberghs, Nitish Thakor
An 8-channel current steerable, multi-phasic neural stimulator with on-chip current DAC calibration and residue nulling for precise charge balancing is presented. Each channel consists of two sub-binary radix DACs followed by wide-swing, high output impedance current buffers providing time-multiplexed source and sink outputs for anodic and cathodic stimulation. A single integrator is shared among channels and serves to calibrate DAC coefficients and to closely match the anodic and cathodic stimulation phases...
January 16, 2017: IEEE Transactions on Biomedical Circuits and Systems
https://www.readbyqxmd.com/read/28077725/encoding-of-both-reaching-and-grasping-kinematics-in-dorsal-and-ventral-premotor-cortices
#2
Kazutaka Takahashi, Matthew D Best, Noah Huh, Kevin A Brown, Adil A Tobaa, Nicholas G Hatsopoulos
: Classically, it has been hypothesized that reach-to-grasp movements arise from two discrete parieto-frontal cortical networks. As part of these networks, the dorsal premotor cortex has been implicated in the control of reaching movements of the arm, while the ventral premotor cortex has been associated with the control of grasping movements of the hand. Recent studies have shown that such a strict delineation of function along anatomical boundaries is unlikely partly because reaching to different locations can alter distal hand kinematics and grasping different objects can affect kinematics of the proximal arm; Here, we used chronically implanted multi-electrode arrays to record unit spiking activity in both PMd and PMv simultaneously while rhesus macaques engaged in a reach-to-grasp task...
January 11, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28074856/local-field-potentials-primarily-reflect-inhibitory-neuron-activity-in-human-and-monkey-cortex
#3
Bartosz Teleńczuk, Nima Dehghani, Michel Le Van Quyen, Sydney S Cash, Eric Halgren, Nicholas G Hatsopoulos, Alain Destexhe
The local field potential (LFP) is generated by large populations of neurons, but unitary contribution of spiking neurons to LFP is not well characterised. We investigated this contribution in multi-electrode array recordings from human and monkey neocortex by examining the spike-triggered LFP average (st-LFP). The resulting st-LFPs were dominated by broad spatio-temporal components due to ongoing activity, synaptic inputs and recurrent connectivity. To reduce the spatial reach of the st-LFP and observe the local field related to a single spike we applied a spatial filter, whose weights were adapted to the covariance of ongoing LFP...
January 11, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28071593/a-lightweight-feedback-controlled-microdrive-for-chronic-neural-recordings
#4
Aleksander Jovalekic, Sophie Cave Lopez, Alessandro Canopoli, Janie Ondracek, Aymeric Nager, Alexei Vyssotski, Richard Hans Robert Hahnloser
OBJECTIVE: Chronic neural recordings have provided many insights into the relationship between neural activity and behavior. We set out to develop a miniaturized motorized microdrive that allows precise electrode positioning despite possibly unreliable motors. APPROACH: We designed a feedback-based motor control mechanism. It contains an integrated position readout from an array of magnets and a Hall sensor. MAIN RESULTS: Our extremely lightweight (<1 g) motorized microdrive allows remote positioning of both metal electrodes and glass pipettes along one motorized axis...
January 10, 2017: Journal of Neural Engineering
https://www.readbyqxmd.com/read/28068291/particle-swarm-optimization-for-programming-deep-brain-stimulation-arrays
#5
Edgar Peña, Simeng Zhang, Steve Deyo, YiZi Xiao, Matthew D Johnson
OBJECTIVE: Deep brain stimulation (DBS) therapy relies on both precise neurosurgical targeting and systematic optimization of stimulation settings to achieve beneficial clinical outcomes. One recent advance to improve targeting is the development of DBS arrays (DBSAs) with electrodes segmented both along and around the DBS lead. However, increasing the number of independent electrodes creates the logistical challenge of optimizing stimulation parameters efficiently. APPROACH: Solving such complex problems with multiple solutions and objectives is well known to occur in biology, in which complex collective behaviors emerge out of swarms of individual organisms engaged in learning through social interactions...
February 2017: Journal of Neural Engineering
https://www.readbyqxmd.com/read/28059382/improving-the-performance-of-an-electrowetting-lenticular-lens-array-by-using-a-thin-polycarbonate-chamber
#6
Junsik Lee, Junoh Kim, Cheoljoong Kim, Dooseub Shin, Gyohyun Koo, Jee Hoon Sim, Yong Hyub Won
In this paper, we used a thin polycarbonate (PC) chamber to improve the performance of an electrowetting lenticular lens array. The polycarbonate chamber changed the radius of curvature (ROC) of the oil acting as a lens, which increased the dioptric power of the liquid lens to 1666.7D. The increase in dioptric power required a reduction in the distance between the optical center of the lens and the display pixels under the chamber, which was accomplished by reducing the thickness of the chamber. The optimal thickness of the chamber was determined to be 0...
December 26, 2016: Optics Express
https://www.readbyqxmd.com/read/28031400/spinal-cord-direct-current-stimulation-differentially-modulates-neuronal-activity-in-the-dorsal-and-ventral-spinal-cord
#7
Weiguo Song, John H Martin
Spinal cord direct current stimulation (sDCS) has the potential for promoting motor function after injury through its modulatory actions on sensory processing, reflex functions, the motor cortex (M1) motor map, and motor output. Here we addressed systems-level mechanisms underlying sDCS neuromodulation of spinal circuits activated by M1 and peripheral forelimb electrical stimulation in anesthetized healthy rats. We determined the effects of cathodal and anodal sDCS (c- and a-sDCS) on local field potentials (LFP) and single-unit activity recorded at 32 sites simultaneously within the 6th cervical segment using a silicon multi-electrode array...
December 28, 2016: Journal of Neurophysiology
https://www.readbyqxmd.com/read/28011833/human-induced-pluripotent-stem-cell-derived-cardiomyocytes-from-cardiac-progenitor-cells-effects-of-selective-ion-channel-blockade
#8
Claudia Altomare, Enea Pianezzi, Elisabetta Cervio, Sara Bolis, Vanessa Biemmi, Patrizia Benzoni, Giovanni G Camici, Tiziano Moccetti, Lucio Barile, Giuseppe Vassalli
AIM: Human-induced pluripotent stem cell (hiPSC)-derived cardiomyocytes are likely to revolutionize electrophysiological approaches to arrhythmias. Recent evidence suggests the somatic cell origin of hiPSCs may influence their differentiation potential. Owing to their cardiomyogenic potential, cardiac-stromal progenitor cells (CPCs) are an interesting cellular source for generation of hiPSC-derived cardiomyocytes. The effect of ionic current blockade in hiPSC-derived cardiomyocytes generated from CPCs has not been characterized yet...
December 2016: Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology
https://www.readbyqxmd.com/read/28006672/gene-electrotransfer-into-skin-using-noninvasive-multi-electrode-array-for-vaccination-and-wound-healing
#9
Spela Kos, Kevin Vanvarenberg, Tanja Dolinsek, Maja Cemazar, Jure Jelenc, Véronique Préat, Gregor Sersa, Gaëlle Vandermeulen
Skin is an attractive target for gene electrotransfer due to its easy accessibility and its interesting immune properties. Since electrodes are often invasive and frequently induce discomfort during pulse application, there is a fundamental need for non-invasive electrodes for skin delivery. We developed circular pin non-invasive multi-electrode array (MEA), suitable for different clinical applications. MEA was first employed to deliver a luciferase reporter gene. Then, it was used to deliver a DNA vaccine coding for ovalbumin or a plasmid encoding hCAP-18/LL-37 for promoting wound healing...
December 10, 2016: Bioelectrochemistry
https://www.readbyqxmd.com/read/27986923/nonlinear-y-like-receptive-fields-in-the-early-visual-cortex-an-intermediate-stage-for-building-cue-invariant-receptive-fields-from-subcortical-y-cells
#10
Amol Gharat, Curtis L Baker
: Many of the neurons in early visual cortex are selective for orientation of boundaries defined by first-order (luminance) as well as second-order (contrast, texture) cues. The neural circuit mechanism underlying this selectivity is still unclear, but some studies have proposed that it emerges from spatial nonlinearities of subcortical Y cells.In order to understand how inputs from the Y cell pathway might be pooled to generate cue-invariant receptive fields, we recorded visual responses from single neurons in cat Area 18 using linear multi-electrode arrays...
December 16, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/27974450/coupling-multi-electrode-array-recordings-with-silver-labeling-of-recording-sites-to-study-cervical-spinal-network-connectivity
#11
Kristi A Streeter, Michael D Sunshine, Shreya R Patel, Savannah S Liddell, Lucy E Denholtz, Paul J Reier, David D Fuller, David M Baekey
Mid-cervical spinal interneurons form a complex and diffuse network and may be involved in modulating phrenic motor output. The intent of the current work was to enable a better understanding of mid-cervical "network level" connectivity by pairing the neurophysiological multi-electrode array (MEA) data with histological verification of the recording locations. We first developed a method to deliver 100 nA currents to electroplate silver onto and subsequently deposit silver from electrode tips after obtaining mid-cervical (C3-5) recordings using an MEA in anesthetized and ventilated adult rats...
December 14, 2016: Journal of Neurophysiology
https://www.readbyqxmd.com/read/27956204/a-new-paradigm-for-drug-induced-torsadogenic-risk-assessment-using-human-ips-cell-derived-cardiomyocytes
#12
Hiroyuki Ando, Takashi Yoshinaga, Wataru Yamamoto, Keiichi Asakura, Takaaki Uda, Tomohiko Taniguchi, Atsuko Ojima, Raku Shinkyo, Kiyomi Kikuchi, Tomoharu Osada, Seiji Hayashi, Chieko Kasai, Norimasa Miyamoto, Hiroyuki Tashibu, Daiju Yamazaki, Atsushi Sugiyama, Yasunari Kanda, Kohei Sawada, Yuko Sekino
INTRODUCTION: Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) are anticipated to be a useful tool for conducting proarrhythmia risk assessments of drug candidates. However, a torsadogenic risk prediction paradigm using hiPSC-CMs has not yet been fully established. METHODS: Extracellular field potentials (FPs) were recorded from hiPSC-CMs using the multi-electrode array (MEA) system. The effects on FPs were evaluated with 60 drugs, including 57 with various clinical torsadogenic risks...
December 10, 2016: Journal of Pharmacological and Toxicological Methods
https://www.readbyqxmd.com/read/27942935/propagation-and-synchronization-of-reverberatory-bursts-in-developing-cultured-networks
#13
Chih-Hsu Huang, Yu-Ting Huang, Chun-Chung Chen, C K Chan
Developing networks of neural systems can exhibit spontaneous, synchronous activities called neural bursts, which can be important in the organization of functional neural circuits. Before the network matures, the activity level of a burst can reverberate in repeated rise-and-falls in periods of hundreds of milliseconds following an initial wave-like propagation of spiking activity, while the burst itself lasts for seconds. To investigate the spatiotemporal structure of the reverberatory bursts, we culture dissociated, rat cortical neurons on a high-density multi-electrode array to record the dynamics of neural activity over the growth and maturation of the network...
December 9, 2016: Journal of Computational Neuroscience
https://www.readbyqxmd.com/read/27923051/electrophysiological-characteristics-of-human-ipsc-derived-cardiomyocytes-for-the-assessment-of-drug-induced-proarrhythmic-potential
#14
Wataru Yamamoto, Keiichi Asakura, Hiroyuki Ando, Tomohiko Taniguchi, Atsuko Ojima, Takaaki Uda, Tomoharu Osada, Seiji Hayashi, Chieko Kasai, Norimasa Miyamoto, Hiroyuki Tashibu, Takashi Yoshinaga, Daiju Yamazaki, Atsushi Sugiyama, Yasunari Kanda, Kohei Sawada, Yuko Sekino
The aims of this study were to (1) characterize basic electrophysiological elements of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) that correspond to clinical properties such as QT-RR relationship, (2) determine the applicability of QT correction and analysis methods, and (3) determine if and how these in-vitro parameters could be used in risk assessment for adverse drug-induced effects such as Torsades de pointes (TdP). Field potential recordings were obtained from commercially available hiPSC-CMs using multi-electrode array (MEA) platform with and without ion channel antagonists in the recording solution...
2016: PloS One
https://www.readbyqxmd.com/read/27921187/rotor-tracking-using-phase-of-electrograms-recorded-during-atrial-fibrillation
#15
Caroline H Roney, Chris D Cantwell, Norman A Qureshi, Rasheda A Chowdhury, Emmanuel Dupont, Phang Boon Lim, Edward J Vigmond, Jennifer H Tweedy, Fu Siong Ng, Nicholas S Peters
Extracellular electrograms recorded during atrial fibrillation (AF) are challenging to interpret due to the inherent beat-to-beat variability in amplitude and duration. Phase mapping represents these voltage signals in terms of relative position within the cycle, and has been widely applied to action potential and unipolar electrogram data of myocardial fibrillation. To date, however, it has not been applied to bipolar recordings, which are commonly acquired clinically. The purpose of this study is to present a novel algorithm for calculating phase from both unipolar and bipolar electrograms recorded during AF...
December 5, 2016: Annals of Biomedical Engineering
https://www.readbyqxmd.com/read/27916876/coriandrum-sativum-and-lavandula-angustifolia-essential-oils-chemical-composition-and-activity-on-central-nervous-system
#16
Lucia Caputo, Lucéia Fátima Souza, Susanna Alloisio, Laura Cornara, Vincenzo De Feo
The aims of this study are to determine the chemical composition of Lavandula angustifolia Mill. and Coriandrum sativum L. essential oils, to evaluate their cytotoxic effects in SH-SY5Y human neuroblastoma cells, to investigate whether an alteration of adenylate cyclase 1 (ADCY1) and of extracellular signal-regulated kinase (ERK) expression can take part in the molecular mechanisms of the essential oils, and to study their possible neuronal electrophysiological effects. The essential oils were obtained by hydrodistillation, and studied by GC and GC-MS...
November 30, 2016: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/27900949/prediction-of-cortical-responses-to-simultaneous-electrical-stimulation-of-the-retina
#17
Kerry J Halupka, Mohit N Shivdasani, Shaun L Cloherty, David B Grayden, Yan T Wong, Anthony N Burkitt, Hamish Meffin
OBJECTIVE: Simultaneous electrical stimulation of multiple electrodes has shown promise in diversifying the responses that can be elicited by retinal prostheses compared to interleaved single electrode stimulation. However, the effects of interactions between electrodes are not well understood and clinical trials with simultaneous stimulation have produced inconsistent results. We investigated the effects of multiple electrode stimulation of the retina by developing a model of cortical responses to retinal stimulation...
November 30, 2016: Journal of Neural Engineering
https://www.readbyqxmd.com/read/27891080/enhanced-burst-suppression-and-disruption-of-local-field-potential-synchrony-in-a-mouse-model-of-focal-cortical-dysplasia-exhibiting-spike-wave-seizures
#18
Anthony J Williams, Chen Zhou, Qian-Quan Sun
Focal cortical dysplasias (FCDs) are a common cause of brain seizures and are often associated with intractable epilepsy. Here we evaluated aberrant brain neurophysiology in an in vivo mouse model of FCD induced by neonatal freeze lesions (FLs) to the right cortical hemisphere (near S1). Linear multi-electrode arrays were used to record extracellular potentials from cortical and subcortical brain regions near the FL in anesthetized mice (5-13 months old) followed by 24 h cortical electroencephalogram (EEG) recordings...
2016: Frontiers in Neural Circuits
https://www.readbyqxmd.com/read/27878736/in-vitro-cyto-biocompatibility-study-of-thin-film-transistors-substrates-using-an-organotypic-culture-method
#19
Eric Leclerc, Jean-Luc Duval, Christophe Egles, Satoshi Ihida, Hiroshi Toshiyoshi, Agnès Tixier-Mita
Thin-Film-Transistors Liquid-Crystal Display has become a standard in the field of displays. However, the structure of these devices presents interest not only in that field, but also for biomedical applications. One of the key components, called here TFT substrate, is a glass substrate with a dense and large array of thousands of transparent micro-electrodes that can be considered as a large scale multi-electrode array(s). Multi-electrode array(s) are widely used for in vitro electrical investigations on neurons and brain, allowing excitation, registration, and recording of their activity...
January 2017: Journal of Materials Science. Materials in Medicine
https://www.readbyqxmd.com/read/27831887/modeling-intracochlear-magnetic-stimulation-a-finite-element-analysis
#20
Sagarika Mukesh, D T Blake, B J McKinnon, P T Bhatti
This study models induced electric fields, and their gradient, produced by pulsatile current stimulation of submillimeter inductors for cochlear implantation. Using finite-element analysis, the lower chamber of the cochlea, scala tympani, is modeled as a cylindrical structure filled with perilymph bounded by tissue, bone, and cochlear neural elements. Single inductors as well as an array of inductors are modeled. The coil strength (~100 nH) and excitation parameters (Peak current of 1 - 5 A, Voltages of 16 - 20 V) are based on a formative feasibility study conducted by our group...
November 2, 2016: IEEE Transactions on Neural Systems and Rehabilitation Engineering
keyword
keyword
85457
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"