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Multi-electrode array

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https://www.readbyqxmd.com/read/28185910/ultrasoft-microwire-neural-electrodes-improve-chronic-tissue-integration
#1
Zhanhong Jeff Du, Christi L Kolarcik, Takashi D Y Kozai, Silvia D Luebben, Shawn A Sapp, Xin Sally Zheng, James A Nabity, X Tracy Cui
: Chronically implanted neural multi-electrode arrays (MEA) are an essential technology for recording electrical signals from neurons and/or modulating neural activity through stimulation. However, current MEAs, regardless of the type, elicit an inflammatory response that ultimately leads to device failure. Traditionally, rigid materials like tungsten and silicon have been employed to interface with the relatively soft neural tissue. The large stiffness mismatch is thought to exacerbate the inflammatory response...
February 6, 2017: Acta Biomaterialia
https://www.readbyqxmd.com/read/28166399/hierarchical-dual-scale-structures-of-atomically-thin-mos2-for-tunable-wetting
#2
Jonghyun Choi, Jihun Mun, Michael Cai Wang, Ali Ashraf, Sang-Woo Kang, SungWoo Nam
Molybdenum disulfide (MoS2), a well-known solid lubricant for low friction surface coatings, has recently drawn attention as an analog two-dimensional (2D) material beyond graphene. When patterned to produce vertically grown, nanoflower-structures, MoS2 shows promise as a functional material for hydrogen evolution catalysis systems, electrodes for alkali metal-ion batteries, and field-emission arrays. Whereas the wettability of graphene has been substantially investigated, that of MoS2 structures, especially nanoflowers, has remained relatively unexplored despite MoS2 nanoflower's potential in future applications...
February 6, 2017: Nano Letters
https://www.readbyqxmd.com/read/28163191/csahi-study-detection-of-drug-induced-ion-channel-receptor-responses-qt-prolongation-and-arrhythmia-using-multi-electrode-arrays-in-combination-with-human-induced-pluripotent-stem-cell-derived-cardiomyocytes
#3
Takashi Kitaguchi, Yuta Moriyama, Tomohiko Taniguchi, Sanae Maeda, Hiroyuki Ando, Takaaki Uda, Koji Otabe, Masao Oguchi, Shigekazu Shimizu, Hiroyuki Saito, Atsushi Toratani, Mahoko Asayama, Wataru Yamamoto, Emi Matsumoto, Daisuke Saji, Hiroki Ohnaka, Norimasa Miyamoto
INTRODUCTION: The use of multi-electrode arrays (MEA) in combination with human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) provides a promising method to predict comprehensive cardiotoxicity, including drug-induced QT prolongation and arrhythmia. We previously demonstrated that MEA in combination with hiPSC-CMs could provide a generalizable platform by using 7 reference drugs at 10 testing facilities. Using this approach, we evaluated responses to reference drugs that modulate a range of cardiac ion currents and have a range of arrhythmogenic effects...
February 2, 2017: Journal of Pharmacological and Toxicological Methods
https://www.readbyqxmd.com/read/28153730/interpretation-of-field-potentials-measured-on-a-multi-electrode-array-in-pharmacological-toxicity-screening-on-primary-and-human-pluripotent-stem-cell-derived-cardiomyocytes
#4
L G J Tertoolen, S R Braam, B J van Meer, R Passier, C L Mummery
Multi electrode arrays (MEAs) are increasingly used to detect external field potentials in electrically active cells. Recently, in combination with cardiomyocytes derived from human (induced) pluripotent stem cells they have started to become a preferred tool to examine newly developed drugs for potential cardiac toxicity in pre-clinical safety pharmacology. The most important risk parameter is proarrhythmic activity in cardiomyocytes which can cause sudden cardiac death. Whilst MEAs can provide medium- to high- throughput noninvasive assay platform, the translation of a field potential to cardiac action potential (normally measured by low-throughput patch clamp) is complex so that accurate assessment of drug risk to the heart is in practice still challenging...
January 30, 2017: Biochemical and Biophysical Research Communications
https://www.readbyqxmd.com/read/28140365/multichannel-activity-propagation-across-an-engineered-axon-network
#5
Han-Chiao Isaac Chen, John Wolf, Douglas Smith
OBJECTIVE: Although substantial progress has been made in mapping the connections of the brain, less is known about how this organization translates into brain function. In particular, the massive interconnectivity of the brain has made it difficult to specifically examine data transmission between two nodes of the connectome, a central component of the "neural code." Here, we investigated the propagation of multiple streams of asynchronous neuronal activity across an isolated in vitro "connectome unit...
January 31, 2017: Journal of Neural Engineering
https://www.readbyqxmd.com/read/28092575/a-cmos-current-steering-neurostimulation-array-with-integrated-dac-calibration-and-charge-balancing
#6
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
#7
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
#8
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
#9
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
#10
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
#11
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
#12
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
#13
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
#14
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...
April 2017: 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
#15
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
#16
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
#17
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
#18
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
#19
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
#20
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
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