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Multielectrode array

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https://www.readbyqxmd.com/read/29024244/local-chemical-stimulation-of-neurons-with-the-fluidfm
#1
Matthias J Aebersold, Harald Dermutz, László Demkó, José F Saenz Cogollo, Shiang-Chi Lin, Conrad Burchert, Moritz Schneider, Doris Ling, Csaba Forró, Hana Han, Tomaso Zambelli, Janos Vörös
Physiological communication between neurons is dependent on the exchange of neurotransmitters at the synapses. Although such chemical signal transmission targets specific receptors and allows for subtle adaptation of the action potential, in vitro neuroscience typically relies on electrical currents and potentials to stimulate neurons. The electric stimulus is unspecific and the confinement of the stimuli within the media is technically difficult to control and introduces large artifacts in electric recordings of the activity...
October 10, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/28973319/differential-effects-of-hcn-channel-block-on-on-and-off-pathways-in-the-retina-as-a-potential-cause-for-medication-induced-phosphene-perception
#2
Sebastian Bemme, Michael Weick, Tim Gollisch
Purpose: Phosphene perception is a characteristic side effect of heart rate-reducing medication that acts on hyperpolarization-activated cyclic nucleotide-gated (HCN) ion channels. It is hypothesized that these phosphenes are caused by blocking HCN channels in photoreceptors and neurons of the retina, yet the underlying changes in visual signal processing in the retina caused by the HCN channel block are still unknown. Methods: We examined the effects of pharmacologic HCN channel block on the encoding of visual signals in retinal ganglion cells by recording ganglion cell spiking activity from isolated mouse retinas mounted on multielectrode arrays...
September 1, 2017: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/28930702/gcamp-expression-in-retinal-ganglion-cells-characterized-using-a-low-cost-fundus-imaging-system
#3
Yao-Chuan Chang, Steven T Walston, Robert H Chow, James D Weiland
OBJECTIVE: Virus-transduced, intracellular-calcium indicators are effective reporters of neural activity, offering the advantage of cell-specific labeling. Due to the existence of an optimal time window for the expression of calcium indicators, a suitable tool for tracking GECI expression in vivo following transduction is highly desirable. APPROACH: We developed a noninvasive imaging approach based on a custom-modified, low-cost fundus viewing system that allowed us to monitor and characterize in vivo bright-field and fluorescence images of the mouse retina...
October 2017: Journal of Neural Engineering
https://www.readbyqxmd.com/read/28924008/primary-generators-of-visually-evoked-field-potentials-recorded-in-the-macaque-auditory-cortex
#4
Yoshinao Kajikawa, John F Smiley, Charles E Schroeder
Prior studies have reported "local" field potential (LFP) responses to faces in the macaque auditory cortex and have suggested that such face-LFPs may be substrates of audiovisual integration. However, while field potentials (FPs) may reflect the synaptic currents of neurons near the recording electrode, due to the use of a distant reference electrode, they often reflect those of synaptic activity occurring in distant sites as well. Thus, FP recordings within a given brain region (e.g., auditory cortex) may be "contaminated" by activity generated elsewhere in the brain...
September 18, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28923928/transparent-conformable-active-multielectrode-array-using-organic-electrochemical-transistors
#5
Wonryung Lee, Dongmin Kim, Naoji Matsuhisa, Masae Nagase, Masaki Sekino, George G Malliaras, Tomoyuki Yokota, Takao Someya
Mechanically flexible active multielectrode arrays (MEA) have been developed for local signal amplification and high spatial resolution. However, their opaqueness limited optical observation and light stimulation during use. Here, we show a transparent, ultraflexible, and active MEA, which consists of transparent organic electrochemical transistors (OECTs) and transparent Au grid wirings. The transparent OECT is made of Au grid electrodes and has shown comparable performance with OECTs with nontransparent electrodes/wirings...
September 18, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28904106/diversity-in-spatial-scope-of-contrast-adaptation-among-mouse-retinal-ganglion-cells
#6
Mohammad Hossein Khani, Tim Gollisch
Retinal ganglion cells adapt to changes in visual contrast by adjusting their response kinetics and sensitivity. While much work has focused on the time scales of these adaptation processes, less is known about the spatial scale of contrast adaptation. For example, do small, localized contrast changes affect a cell's signal processing across its entire receptive field? Previous investigations have provided conflicting evidence, suggesting either that contrast adaptation occurs locally within subregions of a ganglion cell's receptive field or globally over the receptive field in its entirety...
September 13, 2017: Journal of Neurophysiology
https://www.readbyqxmd.com/read/28883759/the-advantage-of-topographic-prominence-adopted-filter-for-the-detection-of-short-latency-spikes-of-retinal-ganglion-cells
#7
Jungryul Ahn, Myoung-Hwan Choi, Kwangsoo Kim, Solomon S Senok, Dong-Il Dan Cho, Kyo-In Koo, Yongsook Goo
Electrical stimulation through retinal prosthesis elicits both short and long-latency retinal ganglion cell (RGC) spikes. Because the short-latency RGC spike is usually obscured by electrical stimulus artifact, it is very important to isolate spike from stimulus artifact. Previously, we showed that topographic prominence (TP) discriminator based algorithm is valid and useful for artifact subtraction. In this study, we compared the performance of forward backward (FB) filter only vs. TP-adopted FB filter for artifact subtraction...
September 2017: Korean Journal of Physiology & Pharmacology
https://www.readbyqxmd.com/read/28871959/dipolar-extracellular-potentials-generated-by-axonal-projections
#8
Thomas McColgan, Ji Liu, Paula Tuulia Kuokkanen, Catherine Emily Carr, Hermann Wagner, Richard Kempter
Extracellular field potentials (EFPs) are an important source of information in neuroscience, but their physiological basis is in many cases still a matter of debate. Axonal sources are typically discounted in modeling and data analysis because their contributions are assumed to be negligible. Here, we established experimentally and theoretically that contributions of axons to EFPs can be significant. Modeling action potentials propagating along axons, we showed that EFPs were prominent in the presence of terminal zones where axons branch and terminate in close succession, as found in many brain regions...
September 5, 2017: ELife
https://www.readbyqxmd.com/read/28842772/pdms-based-multielectrode-arrays-for-superior-in-vitro-retinal-stimulation-and-recording
#9
Satarupa Biswas, Debdeep Sikdar, Debanjan Das, Manjunatha Mahadevappa, Soumen Das
Understanding of the neural response to electrical stimulation requires simultaneous recording from the various neurons of retina. Electrodes form the physical interface with the neural or retinal tissue. Successful retinal stimulation and recording demands conformal integration of these electrodes with the soft tissue to ensure establishment of proper electrical connection with the excitable tissue. Mechanical impedance of polydimethylsiloxane (PDMS) being compliant with that of retinal tissue, offers excellent potential as a substrate for metal electrodes...
August 25, 2017: Biomedical Microdevices
https://www.readbyqxmd.com/read/28819130/a-multielectrode-array-microchannel-platform-reveals-both-transient-and-slow-changes-in-axonal-conduction-velocity
#10
Rouhollah Habibey, Shahrzad Latifi, Hossein Mousavi, Mattia Pesce, Elmira Arab-Tehrany, Axel Blau
Due to their small dimensions, electrophysiology on thin and intricate axonal branches in support of understanding their role in normal and diseased brain function poses experimental challenges. To reduce experimental complexity, we coupled microelectrode arrays (MEAs) to bi-level microchannel devices for the long-term in vitro tracking of axonal morphology and activity with high spatiotemporal resolution. Our model allowed the long-term multisite recording from pure axonal branches in a microscopy-compatible environment...
August 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28795515/multiplexed-optogenetic-stimulation-of-neurons-with-spectrum-selective-upconversion-nanoparticles
#11
Xudong Lin, Ying Wang, Xian Chen, Runhuai Yang, Zixun Wang, Jingyu Feng, Haitao Wang, King W C Lai, Jufang He, Feng Wang, Peng Shi
Optical modulation of nervous system becomes increasingly popular as the wide adoption of optogenetics. For these applications, upconversion materials hold great promise as novel photonic elements. This study describes an upconversion based strategy for combinatorial neural stimulation both in vitro and in vivo by using spectrum-selective upconversion nanoparticles (UCNPs). NaYF4 based UCNPs are used to absorb near-infrared (NIR) energy and to emit visible light for stimulating neurons expressing different channelrhodopsin (ChR) proteins...
September 2017: Advanced Healthcare Materials
https://www.readbyqxmd.com/read/28749937/recurrently-connected-and-localized-neuronal-communities-initiate-coordinated-spontaneous-activity-in-neuronal-networks
#12
Davide Lonardoni, Hayder Amin, Stefano Di Marco, Alessandro Maccione, Luca Berdondini, Thierry Nieus
Developing neuronal systems intrinsically generate coordinated spontaneous activity that propagates by involving a large number of synchronously firing neurons. In vivo, waves of spikes transiently characterize the activity of developing brain circuits and are fundamental for activity-dependent circuit formation. In vitro, coordinated spontaneous spiking activity, or network bursts (NBs), interleaved within periods of asynchronous spikes emerge during the development of 2D and 3D neuronal cultures. Several studies have investigated this type of activity and its dynamics, but how a neuronal system generates these coordinated events remains unclear...
July 2017: PLoS Computational Biology
https://www.readbyqxmd.com/read/28744551/neural-responses-to-multielectrode-stimulation-of-healthy-and-degenerate-retina
#13
Kerry J Halupka, Carla J Abbott, Yan T Wong, Shaun L Cloherty, David B Grayden, Anthony N Burkitt, Evgeni N Sergeev, Chi D Luu, Alice Brandli, Penelope J Allen, Hamish Meffin, Mohit N Shivdasani
Purpose: Simultaneous stimulation of multiple retinal electrodes in normally sighted animals shows promise in improving the resolution of retinal prostheses. However, the effects of simultaneous stimulation on degenerate retinae remain unknown. Therefore, we investigated the characteristics of cortical responses to multielectrode stimulation of the degenerate retina. Methods: Four adult cats were bilaterally implanted with retinal electrode arrays in the suprachoroidal space after unilateral adenosine triphosphate (ATP)-induced retinal photoreceptor degeneration...
July 1, 2017: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/28742044/multipolar-field-shaping-in-a-suprachoroidal-visual-prosthesis
#14
Calvin D Eiber, Socrates Dokos, Nigel H Lovell, Gregg J Suaning
Visual prostheses are now an available mobility aid for patients blinded by degenerative retinal diseases. However, the spatial resolution of existing devices is still insufficient to deliver normal levels of mobility vision without stimulation strategies which enable existing devices to deliver several different percepts per stimulation site. A stimulation strategy in which field shaping is achieved by incorporating multipolar (bipolar and tripolar) stimulation could convey additional information to a user of a visual prosthesis, as compared to monopolar stimulation, is investigated...
July 24, 2017: IEEE Transactions on Neural Systems and Rehabilitation Engineering
https://www.readbyqxmd.com/read/28659709/meclofenamic-acid-improves-the-signal-to-noise-ratio-for-visual-responses-produced-by-ectopic-expression-of-human-rod-opsin
#15
Cyril G Eleftheriou, Jasmina Cehajic-Kapetanovic, Franck P Martial, Nina Milosavljevic, Robert A Bedford, Robert J Lucas
PURPOSE: Retinal dystrophy through outer photoreceptor cell death affects 1 in 2,500 people worldwide with severe impairment of vision in advanced stages of the disease. Optogenetic strategies to restore visual function to animal models of retinal degeneration by introducing photopigments to neurons spared degeneration in the inner retina have been explored, with variable degrees of success. It has recently been shown that the non-steroidal anti-inflammatory and non-selective gap-junction blocker meclofenamic acid (MFA) can enhance the visual responses produced by an optogenetic actuator (channelrhodopsin) expressed in retinal ganglion cells (RGCs) in the degenerate retina...
2017: Molecular Vision
https://www.readbyqxmd.com/read/28634436/dual-coding-theory-explains-biphasic-collective-computation-in-neural-decision-making
#16
Bryan C Daniels, Jessica C Flack, David C Krakauer
A central question in cognitive neuroscience is how unitary, coherent decisions at the whole organism level can arise from the distributed behavior of a large population of neurons with only partially overlapping information. We address this issue by studying neural spiking behavior recorded from a multielectrode array with 169 channels during a visual motion direction discrimination task. It is well known that in this task there are two distinct phases in neural spiking behavior. Here we show Phase I is a distributed or incompressible phase in which uncertainty about the decision is substantially reduced by pooling information from many cells...
2017: Frontiers in Neuroscience
https://www.readbyqxmd.com/read/28619993/low-extracellular-potassium-prolongs-repolarization-and-evokes-early-afterdepolarization-in-human-induced-pluripotent-stem-cell-derived-cardiomyocytes
#17
Jukka Kuusela, Kim Larsson, Disheet Shah, Chandra Prajapati, Katriina Aalto-Setälä
Long QT syndrome (LQTS) is characterized by a prolonged QT-interval on electrocardiogram and by increased risk of sudden death. One of the most common and potentially life-threatening electrolyte disturbances is hypokalemia, characterized by low concentrations of K(+) Using a multielectrode array platform and current clamp technique, we investigated the effect of low extracellular K(+) concentration ([K(+)]Ex) on the electrophysiological properties of hiPSC-derived cardiomyocytes (CMs) generated from a healthy control subject (WT) and from two symptomatic patients with type 1 of LQTS carrying G589D (LQT1A) or IVS7-2A>G mutation (LQT1B) in KCNQ1 The baseline prolongations of field potential durations (FPDs) and action potential durations (APDs) were longer in LQT1-CMs than in WT-CMs...
June 15, 2017: Biology Open
https://www.readbyqxmd.com/read/28534411/intracellular-and-extracellular-recording-of-spontaneous-action-potentials-in-mammalian-neurons-and-cardiac-cells-with-3d-plasmonic-nanoelectrodes
#18
Michele Dipalo, Hayder Amin, Laura Lovato, Fabio Moia, Valeria Caprettini, Gabriele C Messina, Francesco Tantussi, Luca Berdondini, Francesco De Angelis
Three-dimensional vertical micro- and nanostructures can enhance the signal quality of multielectrode arrays and promise to become the prime methodology for the investigation of large networks of electrogenic cells. So far, access to the intracellular environment has been obtained via spontaneous poration, electroporation, or by surface functionalization of the micro/nanostructures; however, these methods still suffer from some limitations due to their intrinsic characteristics that limit their widespread use...
June 14, 2017: Nano Letters
https://www.readbyqxmd.com/read/28507435/mesoporous-silica-nanoparticles-trigger-mitophagy-in-endothelial-cells-and-perturb-neuronal-network-activity-in-a-size-and-time-dependent-manner
#19
Antonina Orlando, Emanuela Cazzaniga, Maria Tringali, Francesca Gullo, Andrea Becchetti, Stefania Minniti, Francesca Taraballi, Ennio Tasciotti, Francesca Re
PURPOSE: Mesoporous silica nanoparticles (MSNPs) are excellent candidates for biomedical applications and drug delivery to different human body areas, the brain included. Although toxicity at cellular level has been investigated, we are still far from using MSNPs in the clinic, because the mechanisms involved in the cellular responses activated by MSNPs have not yet been elucidated. MATERIALS AND METHODS: This study used an in vitro multiparametric approach to clarify relationships among size, dose, and time of exposure of MSNPs (0...
2017: International Journal of Nanomedicine
https://www.readbyqxmd.com/read/28483438/construction-of-vascularized-pacemaker-tissues-by-seeding-cardiac-progenitor-cells-and-endothelial-progenitor-cells-into-matrigel
#20
Luping Zhang, Xiaotong Li, Xiaolong Yu, Yuquan Li, Aijun Sun, Chao Huang, Feng Xu, Jinping Guo, Yao Sun, Xi Zhang, Xiangqun Yang, Chuansen Zhang
AIMS: Transplantation of a tissue engineered cardiac pacemaker (TECP) may represent a novel therapy for cardiac sinus node dysfunction. We previously reported that cardiac progenitor cells (CPCs) derived from embryonic heart tubes could differentiate into cardiac pacemaking cells after endothelin-1 treatment. We aimed to examine the feasibility of TECP fabricated from CPCs-derived pacemaking cells and vascularization of TECP fabricated from CPCs-derived pacemaking cells and endothelial progenitor cells (EPCs) in vitro and in vivo implantation...
June 15, 2017: Life Sciences
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