microelectrodes

In this study we compare oxygen tension (PO2) histograms measured with O2 microelectrodes and a new optical PO2 measurement device, the OxyLite, in normal tissues (mouse spleen and thymus) and in tumors (R3230Ac in rats) (n = 5-6)...

..Silicon technology is a promising approach for high-density, high-resolution sampling of neuronal activity in both basic research and prosthetic devices...

..Here, we demonstrate the reliability of a regular array of 100 microelectrodes to obtain neural recordings from primary motor cortex (MI) of monkeys for at least three months and up to 1...

..The response was altered or disappeared when synaptic transmission was blocked. Our results indicate that shape perception and object location can be partially achieved with subretinal electrical multisite stimulation...

..Application of DNQX, an AMPA antagonist, blocked all spontaneous activity, suggesting that the activity is excitatory and mediated through glutamate receptors...

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..Our results indicate that the pattern of activated neurons likely arises from the direct activation of axons in a volume tens of microns in diameter...

..Our data illustrate that hypothesized clusters of highly interconnected neurons are capable of overcoming interneuron feedback inhibition, resulting in generation of epileptiform bursts, eventually leading to seizure activity...

..use of 16S rRNA gene-cloning analysis, real-time quantitative polymerase chain reaction (RTQ-PCR) assays, and microelectrodes. The goal of this research was to evaluate the contribution of nitrifying activity in the sediment to the ..

..The large-scale integration of such dual-side and multilayer arrays is expected to provide massively parallel recording capabilities in the brain...

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..The present study revealed an extensive excitatory network in the dSC that may contribute to the generation of activity by a large population of neurons that discharge before a saccade...

..We were able to insert the probe into a rat's brain and measure the neural signals with the electrode...

..To develop a liquid crystal polymer (LCP)-based, long-term implantable, retinal stimulation microelectrode array using a novel fabrication method...

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..movements in rabbit and rat ventricular muscle were compared using extracellular double-barreled Ca-selective microelectrodes. In rabbit ventricle, steady-state twitches were associated with transient extracellular Ca (Cao) depletions, ..

..For the study of neurotransmitter release in vivo, larger cylindrical microelectrodes are advantageous because the secreted molecules come from multiple terminals near the electrode, and the ..

..It is anticipated that this kind of approach will help to quantify pharmacological responses of networks used as biosensors...

..We can thus better understand the meaning of neuronal network patterns and connection directions...

..S. Food and Drug Administration (FDA)-approved clinical trial...

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..Here we report an approach to induce Aplysia californica neurons to actively engulf protruding microelectrodes, providing 'in-cell recordings' of subthreshold synaptic and action potentials with signal-to-noise ratio ..

..however, the perceptual effects of auditory cortical microstimulation delivered through penetrating microelectrodes have not been clearly elucidated...

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..Our findings are consistent with the small number of published studies on STN somatopy in the human and the nonhuman primate...

..To determine electrical thresholds required for extracellular activation of retinal ganglion cells as part of a project to develop an epiretinal prosthesis...

..We review previous epiretinal stimulation studies and discuss our results in the context of 32 other publications, comparing threshold parameters and safety limits...

..To illustrate the application to real data, iCSD estimates of stimulus-evoked responses measured with laminar electrodes in the rat somatosensory (barrel) cortex are compared to estimates from the standard CSD method...

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..66 +/- 1.30 nC/cm2, respectively, while the required charge was 12.5 +/- 6.2 and 19 +/- 3.3 nC...

Arrays of microelectrodes used for monitoring single- and multi-neuronal action potentials often fail to record from the same population of neurons over a period of time for several technical and biological reasons...

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..The results show that the impedance error of the particle is about 3%. Finally, the developed structure is applied to trap and measure the impedance of a HeLa cell...

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Networks of single-walled carbon nanotubes were assembled onto microelectrodes by dielectrophoresis...

..We concluded that the conductivity profile must be included in future developments of CSD analysis, especially for rodents...

..Along with the implantable capacity inherent in the CFMEs, these striking analytical properties of the CFME-based biosensors substantially make them potential for in vivo determination of O(2)(-)...

..For retaining the merit of microfabrication, the microelectrodes were deposited on the substrate to reduce the voltage required, due to the shortened spacing between them...

The preparation and interesting electrochemical properties of carbon nanotube (CNT) fiber microelectrodes are reported...

..Further work will be needed to determine how these micro-field potentials, which demonstrate selectivity for one eye, relate to the distribution of the ocular dominance columns of the occipital cortex...

..The goal of this study was to determine whether a nonpenetrating, high-density microwire array could provide sufficient information to serve as the interface for decoding motor cortical signals...

The in vivo use of carbon-fiber microelectrodes for neurochemical investigation has proven to be selective and sensitive when coupled with background-subtracted fast-scan cyclic voltammetry (FSCV)...

..Secondarily, to evaluate whether the longevity of the MER and lead placement effects were influenced by target location (subthalamic nucleus (STN) or globus pallidus interna (GPi))...

..Interdigitated array microelectrodes (IDAM) have been integrated with impedance detection in order to miniaturize the conventional electrodes, ..

..The vertical arrangement of the recording sites on these electrodes is ideal for simultaneously recording across the different layers of brain areas such as the cerebral cortex and hippocampus in chronic preparations...

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..The interface characteristics must be considered during interpretation of studies undertaken in vitro or in acute experiments in vivo, where physiological fluid is abundant...

The voltammetric responses of carbon-fiber microelectrodes with a 1.0 V and a 1.4 V anodic limit were compared in this study. Fast-scan cyclic voltammetry was used to characterize the response to dopamine and several other neurochemicals...

..e., smoothly tapering diameter) with a corresponding mechanically stable shank...

..Several structures relevant to the fabrication of microelectrode arrays are also offered in order to demonstrate the capabilities of EDM...

..chip is described which combines a microfluidic network fabricated in a silicone elastomer (PDMS) with planar microelectrodes. It was used to measure extracellular potentials from single adult murine cardiac myocytes in a restricted ..

..The method does not require expensive clean room facilities and offers an extremely short design-to-prototype time of below 1 day. First prototypes demonstrate a minimal achievable feature size of about 30 microm...

..These data indicate that factors, which influence adherence of neurons to surfaces, can profoundly impact both neuronal network morphology and electrophysiological activity in vitro...

..To investigate the responses of retinal ganglion cells (RGCs) to electrical stimulation, using electrodes comparable in size to those used in human studies investigating the feasibility of an electronic retinal prosthesis...

..Previously, fast-scan cyclic voltammetry at carbon-fiber microelectrodes was used for the measurement of such pH transients...

Arrays of closely spaced quartz-insulated, platinum-tungsten microelectrodes are widely used to obtain acute recordings from chronically prepared subjects...

..In most cases, these changes did parallel an improvement in SNR. These findings suggest that rejuvenation may be a useful intervention strategy to prolong the lifetime of chronically implanted microelectrodes.

..In addition, we evaluated the three-dimensional profile of the stimulation voltage distribution to assess the importance of close retinal contact for high resolution stimulation...

..Careful cleaning is not only important to avoid foreign body response, but can also reduce the stress applied to the electrode while penetrating the brain tissue...

..Following dye loading, the isolated retina was mounted on a microelectrode array to demonstrate that electrical activity and calcium activity were preserved, as the retina responded to electrical stimuli...

..Successful electrophysiological recordings were made from very thin electrodes implanted in this fashion...

..b>Microelectrodes are compared in implanted rats through impedance, charge capacity, signal-to-noise ratio, recording stability,..

..These findings suggest that rejuvenation may be an intervention strategy to prolong the functional lifetime of chronically implanted microelectrodes.

..This study was conducted to investigate how the brightness of percepts is affected by pulse timing across electrodes in two of these patients...

..However, little attention has been paid to the image artefacts produced by the microelectrodes that compromise the anatomical or functional information of those studies...

..Threshold stimulation currents and the lateral extent of the stimulation zone were computed for disc microelectrodes in subretinal stimulation mode...

Activated iridium microelectrodes were implanted for 450-1282 days in the sensorimotor cortex of seven adult domestic cats and then pulsed for 240 h (8 h per day for 30 days) at 50 Hz...

Intracortical microelectrodes puncture the intact pia mater membrane during insertion, a process that can cause brain dimpling and trauma...

The polymer, Parylene-C, has proven to be a biocompatible insulation for microelectrodes. However, due to its inert nature, the removal of the insulation from the tips of microelectrodes is difficult...

We have used quartz Ca2+-sensitive microelectrodes (CASMs) in large voltage-clamped snail neurones to investigate the inward spread of Ca2+ after a brief depolarisation...

..25 ng/mL. Since the cut-off limit of T-PSA between prostate hyperplasia and cancer is 4 ng/mL, the performance of our label-free electrochemical immunosensor seems promising for further clinical applications...

..development of a novel neuroelectronic interface consisting of an array of noninvasive gold-mushroom-shaped microelectrodes (gMmicroEs) that practically provide intracellular recordings and stimulation of many individual neurons, ..

..Pixel sizes are scalable from 100 to 25 microm, corresponding to 640-10,000 pixels on an implant 3 mm in diameter...

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..The technique can also be used for the rapid assessment of food-processing treatments aimed at reducing bacterial contamination of food and for the development of strategies to assess the resistance of organisms to antimicrobial agents...

..from dissociated embryonic murine spinal cord and auditory cortex and grown on substrate-integrated thin-film microelectrodes to determine characteristic responses to the cannabinoid agonists anandamide (AN) and methanandamide (MA)...

..Membrane-sealed dishes will also be useful for the culture of many other cell types susceptible to evaporation and contamination...

Many different types of microelectrodes have been developed for use as a direct Brain-Machine Interface (BMI) to chronically recording single neuron action potentials from ensembles of neurons...

..We evaluate the Lead point compared to the NeuroTrek system. We used NeuroTrek in 18 Parkinsonian patients, Lead point-4 in 12 patients, during STN-DBS surgery. We compared MR-Stir image with Microelectrode recording...

..Recently, microelectrodes that can produce extremely localized electric fields, such as solid carbon fiber microelectrodes, electrolyte-..

..In this study, linear arrays of 24 microelectrodes were used to estimate population synaptic currents and neuronal firing in different layers of ACC during ..

..the anal papillae of larvae of the mosquito Aedes aegypti were measured using self-referencing ion-selective microelectrodes. The gradients were used to calculate estimates of ion fluxes into and out of the papillae...

..Future studies with longer implant durations can confirm if this observation remains consistent beyond 4 weeks...

..We have used our sensors to make the first demonstration that ATP is released from spinal networks in vivo during locomotor activity...

..C virus based on electrostatic modulation of the ion-exchange kinetics of a polypyrrole film deposited at microelectrodes. Synthetic single-stranded 18-mer HCV genotype-1-specific probe DNA has been immobilized at a 2,5-bis(2-..

..The averaged impedance value at 1 KHz was approximately 1.2 MOmega. Simultaneous recordings of neural signals from barrel cortex of a rat were successfully demonstrated...

..By using five parallel trajectories, often two to three microelectrodes allow us to recognize subthalamic nucleus (STN) neuronal activity...

..More generally, these results demonstrate how the properties of neuronal systems can be inferred from the statistics of their input...

..Spikes corresponding to single cell activity could be monitored in the hippocampus CA3 and CA1 region using 3D electrodes...

..In terms of safety for the patients, however, MER techniques are relatively safe, but non-Mer techniques, based on macrostimulation-guided surgery, are at least five times safer...

..Additionally, biophysical basics of recording and concepts for analysis of extracellular electrical signals are presented...

..in both groups, the rate of severe complications, such as hematoma, and mortality appeared to be higher when microelectrodes were used, both in ablative surgery and in DBS procedures...

..Thus, the embryonic stem cells potentially represent a renewable cell source for the cell-based biosensors...

We have developed an array of microelectrodes that is suitable for long-term implantation into the subthalamic nucleus (STN) or the globus pallidus and is able to record from single neurons, as well as deliver localized microstimulation...

..Trehalose was electrooxidized at pH 7.2 already at -0.36 V versus Ag/AgCl. At 0 V versus Ag/AgCl the trehalose electrooxidation current density was 0.1 mA/cm(2)...

..traditional electrode recording sites with the intent of improving the long-term performance of cortical microelectrodes. Conductive polymers can drastically decrease recording site impedance, which in turn is hypothesized to ..

..53 +/- 0.08 octave per millimeter. This study demonstrates the use of high electrode count, microelectrode array recordings in characterizing the spatial distribution of acoustic information in the feline AI...

There is a great need for silicon microelectrodes that can simultaneously monitor the activity of many neurons in the brain...

..Circuit size is 2.4 mm per 11.2 mm (0.35 microm CMOS process) and its power consumption is about 125 mW...

..The voltage field for any device size and current, and any specific resistance of the volume conductor can be predicted from these results so long as the aspect ratios are preserved...

..In animal studies, penetrating microelectrodes are better able to convey the spectral information of sound, and NF2 patients whose auditory brainstem ..

..In animal studies, penetrating microelectrodes are better able to convey the spectral information of sound, and NF2 patients whose auditory brainstem ..

..recording technologies are being developed and commercialized for chronic human use: 1) small intracortical microelectrodes that are implanted a few millimeters into the brain and can detect the firing activity of many individual ..

..rate of oxygen exit from arterioles by diffusion a phenomenon measured by other investigators using oxygen microelectrodes and the change in microvessel blood oxygen saturation and by us using the phosphorescence quenching technique...

..To test our hypotheses, we will acquire data simultaneously from 128 single neuron microelectrodes implanted in the primary motor cortex hand representation, from 16 electromyographic electrodes implanted in ..

..To test our hypotheses, we will acquire data simultaneously from 128 single neuron microelectrodes implanted in the primary motor cortex hand representation, from 16 electromyographic electrodes implanted in ..

..b>Microelectrodes offer faster kinetics, as well as sensitivity in monitoring protein binding...

..To evaluate events after exocytosis, carbon-fiber microelectrodes can be placed in tissue slices maintained in physiological buffer...

..To evaluate events after exocytosis, carbon-fiber microelectrodes can be placed in tissue slices maintained in physiological buffer...

..objectives, and in which ionic and nitric oxide fluxes will be measured in real time using selective microelectrodes. We will focus on two epithelia, the epididymis, which is at the core of our research program, and the ..

..objectives, and in which ionic and nitric oxide fluxes will be measured in real time using selective microelectrodes. We will focus on two epithelia, the epididymis, which is at the core of our research program, and the ..

..will be provided not only by myotube contraction, but also by stimulating and recording microelectrodes flanking the myelination compartment, that allow for direct measurements of conduction velocity changes ..

..responses of these cells under background and bleach-adapted conditions will be obtained using suction microelectrodes. Changes in visual pigment content will be measured using microspectrophotometry...

..Adsorption of neurotransmitters on carbon-fiber microelectrodes contributes to the sensitivity of these probes in vivo, but it also decreases response time...

..Both are electroactive and amenable to detection with fast-scan cyclic voltammetry at carbon-fiber microelectrodes. Three specific aims focus on new technology (1, 3, and 5), to be evaluated in anesthetized rats, and two ..

..The proposal addresses the RFA's invitation to "develop microelectrodes that can simultaneously stimulate and record and perform microdialysis or infuse chemicals"...

..cells in intact villi using BCECF ratio microfluorimetry to measure intracellular pH (pHi), single-barreled microelectrodes to measure apical membrane potential, and laser capture dissection coupled with quantitative real-time PCR ..

..cells in intact villi using BCECF ratio microfluorimetry to measure intracellular pH (pHi), single-barreled microelectrodes to measure apical membrane potential, and laser capture dissection coupled with quantitative real-time PCR ..

..The subsequent distribution of the molecules will be measured using ion-selective microelectrodes (for tetramethylammonium and potassium), fast scan cyclic voltammetry (for dopamine) and integrative optical ..

..An array of stimulating microelectrodes distributed through the target nucleus would permit precise control of the spatial distribution of the ..

..An array of stimulating microelectrodes distributed through the target nucleus would permit precise control of the spatial distribution of the ..

..Intravital microscopy and O2 microelectrodes will be used to measure temporal changes in blood flow and perivascular 02 levels and if temporal variations ..

..nervous system diseases require implantation of electrically conductive interfaces between neural tissues and microelectrodes. Currently available metal/silicon-based devices are not stable over the long term, mostly due to gliosis and ..

..between compartments has been monitored using a variety of techniques which involve ion-selective microelectrodes. Such electrodes can be sealed into the cochlea, permitting measurements to be made while avoiding artifacts ..

..nervous system diseases require implantation of electrically conductive interfaces between neural tissues and microelectrodes. Currently available metal/silicon-based devices are not stable over the long term, mostly due to gliosis and ..

..Stimulation with microelectrodes will be used to test the hypothesis that (iii) muscle fiber contraction results in perfusion of MVUs along ..

..of cell volume and determinants of the intracellular ion activities of K+, Na+, Cl- and H+ with ion-selective microelectrodes (ISE) in both isolated ventricular myocytes and papillary muscles from adult and neonatal rabbit hearts...

..We will use intracellular microelectrodes and tension recordings to determine the basic responses of the longitudinal and circular muscle layers to ..