Showing papers on "Electrode array published in 2013"

A carbon-fiber electrode array for long-term neural recording.

Abstract: Objective. Chronic neural recording in behaving animals is an essential method for studies of neural circuit function. However, stable recordings from small, densely packed neurons remains challenging, particularly over time-scales relevant for learning. Approach. We describe an assembly method for a 16-channel electrode array consisting of carbon fibers (<5??m diameter) individually insulated with Parylene-C and fire-sharpened. The diameter of the array is approximately 26??m along the full extent of the implant. Main results. Carbon fiber arrays were tested in HVC (used as a proper name), a song motor nucleus, of singing zebra finches where individual neurons discharge with temporally precise patterns. Previous reports of activity in this population of neurons have required the use of high impedance electrodes on movable microdrives. Here, the carbon fiber electrodes provided stable multi-unit recordings over time-scales of months. Spike-sorting indicated that the multi-unit signals were dominated by one, or a small number of cells. Stable firing patterns during singing confirmed the stability of these clusters over time-scales of months. In addition, from a total of 10 surgeries, 16 projection neurons were found. This cell type is characterized by sparse stereotyped firing patterns, providing unambiguous confirmation of single cell recordings. Significance. Carbon fiber electrode bundles may provide a scalable solution for long-term neural recordings of densely packed neurons.

Single layer capacitive imaging sensors

Abstract: Embodiments of the invention generally provide an input device that includes a plurality of sensing elements that are interconnected in desired way to acquire positional information of an input object, so that the acquired positional information can be used by other system components to control a display or other useful system components. One or more of the embodiments described herein, utilizes one or more of the techniques and sensor electrode array configuration disclosed herein to reduce or minimize the number of traces and/or electrodes required to sense the position of an input object within a sensing region of the input device.

Opto- $\mu{\rm ECoG}$ Array: A Hybrid Neural Interface With Transparent $\mu{\rm ECoG}$ Electrode Array and Integrated LEDs for Optogenetics

Abstract: Electrocorticogram (ECoG) recordings, taken from electrodes placed on the surface of the cortex, have been successfully implemented for control of brain machine interfaces (BMIs). Optogenetics, direct optical stimulation of neurons in brain tissue genetically modified to express channelrhodopsin-2 (ChR2), enables targeting of specific types of neurons with sub-millisecond temporal precision. In this work, we developed a BMI device, called an Opto- μECoG array, which combines ECoG recording and optogenetics-based stimulation to enable multichannel, bi-directional interactions with neurons. The Opto- μECoG array comprises two sub-arrays, each containing a 4 × 4 distribution of micro-epidural transparent electrodes (~200 μm diameter) and embedded light-emitting diodes (LEDs) for optical neural stimulation on a 2.5×2.5 mm2 footprint to match the bilateral hemispherical area of the visual cortex in a rat. The transparent electrodes were fabricated with indium tin oxide (ITO). Parylene-C served as the main structural and packaging material for flexibility and biocompatibility. Optical, electrical, and thermal characteristics of the fabricated device were investigated and in vivo experiments were performed to evaluate the efficacy of the device.

The flexDrive: an ultra-light implant for optical control and highly parallel chronic recording of neuronal ensembles in freely moving mice

Abstract: Electrophysiological recordings from ensembles of neurons in behaving mice are a central tool in the study of neural circuits. Despite the widespread use of chronic electrophysiology, the precise positioning of recording electrodes required for high-quality recordings remains a challenge, especially in behaving mice. The complexity of available drive mechanisms, combined with restrictions on implant weight tolerated by mice, limits current methods to recordings from no more than 4-8 electrodes in a single target area. We developed a highly miniaturized yet simple drive design that can be used to independently position 16 electrodes with up to 64 channels in a package that weighs ~2 g. This advance over current designs is achieved by a novel spring-based drive mechanism that reduces implant weight and complexity. The device is easy to build and accommodates arbitrary spatial arrangements of electrodes. Multiple optical fibers can be integrated into the recording array and independently manipulated in depth. Thus, our novel design enables precise optogenetic control and highly parallel chronic recordings of identified single neurons throughout neural circuits in mice.

A new high-density (25 electrodes/mm2) penetrating microelectrode array for recording and stimulating sub-millimeter neuroanatomical structures

Abstract: Objective. Among the currently available neural interface devices, there has been a need for a penetrating electrode array with a high electrode-count and high electrode-density (the number of electrodes/mm 2 ) that can be used for electrophysiological studies of sub-millimeter neuroanatomical structures. We have developed such a penetrating microelectrode array with both a high electrode-density (25 electrodes/mm 2 ) and high electrode-count (up to 96 electrodes) for small nervous system structures, based on the existing Utah Slanted Electrode Array (USEA). Such high electrode-density arrays are expected to provide greater access to nerve fibers than the conventionally spaced USEA especially in small diameter nerves. Approach. One concern for such high density microelectrode arrays is that they may cause a nerve crush-type injury upon implantation. We evaluated this possibility during acute (<10 h) in vivo experiments with electrode arrays implanted into small diameter peripheral nerves of anesthetized rats (sciatic nerve) and cats (pudendal nerve). Main results. Successful intrafascicular implantation and viable nerve function was demonstrated via microstimulation, single-unit recordings and histological analysis. Measurements of the electrode impedances and quantified electrode dimensions demonstrated fabrication quality. The results of these experiments show that such high density neural interfaces can be implanted acutely into neural tissue without causing a complete nerve crush injury, while mediating intrafascicular access to fibers in small diameter peripheral nerves. Significance. This new penetrating microelectrode array has characteristics un-matched by other neural interface devices currently available for peripheral nervous system neurophysiological research.

Leads with X-ray fluorescent capsules for electrode identification and methods of manufacture and use

Abstract: An implantable lead for an electrical stimulation system includes a lead body having a distal end, a proximal end, a longitudinal length, and a circumference; a plurality of electrodes disposed along the distal end of the lead body in an electrode array; a plurality of terminals disposed along the proximal end of the lead body; a plurality of conductors electrically coupling the plurality of electrodes to the plurality of terminals; and at least one capsule including an x-ray fluorescent material and disposed along the distal end of the lead body relative to the electrode array to indicate, when viewed fluoroscopically, an orientation of the electrode array. The plurality of electrodes includes a plurality of segmented electrodes. Each of the plurality of segmented electrodes extends partially around the circumference of the lead body.

System and method for managing pain

Abstract: A system and method for managing pain, configured to be worn by a patient, comprising an electrode array comprising a first electrode and a second electrode for providing a TENS treatment to the patient; a connector configured to couple at least one of the first electrode and the second electrode to an electronics subsystem; a muscle twitch sensor subsystem configured to detect a muscle twitch profile induced by the electrode array at the patient; and an electronics subsystem comprising a power module configured to power the system, a pulse generator coupled to the electrode array and configured to transmit the TENS treatment, and a control module configured to receive an input, from the muscle twitch sensor subsystem, characterizing the muscle twitch profile, wherein the electronics subsystem is configured to modulate a parameter of the TENS treatment based upon the input, until a threshold is satisfied.

Burner with flame position electrode array

Abstract: A burner includes a flame positioning mechanism. The flame positioning mechanism includes a flame charger, a plurality of electrodes placed a respective distances along a fuel stream propagation path, and an electrode switch configured to place a subset of the plurality of electrodes into electrical continuity with a holding voltage. Current flow between the flame charge and the holding voltage anchors the flame to an electrode placed into electrical continuity with the holding voltage.

Agglomeration and charge loss sensor for measuring particulate matter

Abstract: A sensor includes a housing, a central sensor electrode assembly, an insulating member, and a trace. The central sensor electrode assembly is coupled to a supply side of a voltage source. The insulating member is coupled between the housing and the central sensor electrode assembly. The insulating member circumscribes a section of the central sensor electrode assembly. The trace is coupled to the insulating member and circumscribes the section of the central sensor electrode assembly. The trace directs at least a portion of leakage current away from a voltage ground offset on an opposite side of the central sensor electrode assembly.

A micromachined impedance biosensor for accurate and rapid detection of E. coli O157:H7

Abstract: An impedance biosensor based on interdigitated electrode (IDE) arrays was designed, fabricated and tested for detection of Escherichia coli O157:H7. The device consists of two sets of gold IDE arrays embedded in a SU8-PDMS microchannel. The first set of electrodes uses positive dielectrophoresis (p-DEP) force to focus and concentrate the E. coli into the centre of the microchannel, and direct it towards the detection zone microchannel which has dimensions of a third of the first channel. The bulk fluid keeps flowing toward the outer channel into the waste outlets. The second sets of electrodes are located in the centre channel and are used for impedimetric detection of the E. coli. A combination of standard photolithography, wet etching and plasma treatment techniques were used to fabricate the biosensor. The E. coli cells in the test solution were focused into the centre of the channel when an excitation signal of 5 Vp–p at 5.6 MHz was applied across the electrode arrays. Before injecting the E. coli cells, polyclonal anti-E. coli antibodies were non-specifically immobilized on the sensing electrode array. This ensures specific detection of E. coli O157:H7 bacterial cells. As the concentrated E. coli cells (antigen) reach the sensing electrode array, they bind to the immobilized antibody sites. This antigen–antibody binding causes a change in the impedance, which is measured using an impedance analyzer. The device performance was tested by measuring the impedance, between 100 Hz and 1 MHz frequency, before and after applying p-DEP on the focusing electrode array, and after applying p-DEP on both the focusing and sensing electrodes. The result shows clearly that the use of p-DEP on the focusing IDE array significantly increased the measurement sensitivity with the lower detection limit being 3 × 102 CFU mL−1. In addition, the use of p-DEP on both electrode arrays increased the measurement sensitivity by a factor of 2.9 to 4.5 times depending on the concentration.

Electrodes, electrochemical cells, and methods of forming electrodes and electrochemical cells

Abstract: Electrodes and methods of forming electrodes are described herein. The electrode can be an electrode of an electrochemical cell or battery. The electrode includes a current collector and a film in electrical communication with the current collector. The film may include a carbon phase that holds the film together. The electrode further includes an electrode attachment substance that adheres the film to the current collector.

Evolution of electrode array diameter for hearing preservation in cochlear implantation.

Abstract: Conclusion: Residual hearing could be preserved with various arrays ranging from 16 to 18 mm in insertion length and 0.25 to 0.5 mm tip diameter. Whether array insertion is performed through a coch...

A hybrid PDMS-Parylene subdural multi-electrode array

Abstract: In this paper, we report on a cost effective and simple method for fabricating a flexible multi-electrode array for subdural neural recording. The electrode was fabricated using a PDMS-Parylene bilayer to combine the major advantages of both materials. Mechanical and electrical characterizations were performed to confirm functionality of a 16-site electrode array under various flexed/bent conditions. The electrode array was helically wound around a 3 mm diameter cylindrical tube and laid over a 2 cm diameter sphere while maintaining its recording capability. Experimental results showed impedance values between 300 kΩ and 600 kΩ at 1 kHz for 90 μm diameter gold recording sites. Acoustically evoked neural activity was successfully recorded from rat auditory cortex, confirming in vivo functionality.

Regenerative Scaffold Electrodes for Peripheral Nerve Interfacing

Abstract: Advances in neural interfacing technology are required to enable natural, thought-driven control of a prosthetic limb. Here, we describe a regenerative electrode design in which a polymer-based thin-film electrode array is integrated within a thin-film sheet of aligned nanofibers, such that axons regenerating from a transected peripheral nerve are topographically guided across the electrode recording sites. Cultures of dorsal root ganglia were used to explore design parameters leading to cellular migration and neurite extension across the nanofiber/electrode array boundary. Regenerative scaffold electrodes (RSEs) were subsequently fabricated and implanted across rat tibial nerve gaps to evaluate device recording capabilities and influence on nerve regeneration. In 20 of these animals, regeneration was compared between a conventional nerve gap model and an amputation model. Characteristic shaping of regenerated nerve morphology around the embedded electrode array was observed in both groups, and regenerated axon profile counts were similar at the eight week end point. Implanted RSEs recorded evoked neural activity in all of these cases, and also in separate implantations lasting up to five months. These results demonstrate that nanofiber-based topographic cues within a regenerative electrode can influence nerve regeneration, to the potential benefit of a peripheral nerve interface suitable for limb amputees.

A Largely Deformable Surface Type Neural Electrode Array Based on PDMS

Abstract: This paper describes a largely deformable surface type neural electrode array based on polydimethylsiloxane (PDMS) for cortical use. Noncracked and reliable metal patterns were fabricated successfully on PDMS substrate by employing an intermediate parylene layer. The mechanical and electrical stability of the fabricated electrode arrays was demonstrated by repeatable bending test using a custom-designed bending test module. Also the adhesion of the electrode structure consisting of PDMS, parylene and metal layers was proven by ASTM tape test. The electrode impedance was measured in phosphate buffered saline (PBS) solution at 37°C over three months and analyzed using equivalent circuit models. Based on these results, it is concluded that the suggested electrode array provides a largely deformable structure with mechanical integrity and electrical stability, which can withstand mechanical stresses when inserted through a small trephination hole in the skull and expanded in the small room between the cortex and the skull without damage to the electrode array.

Electrodynamic combustion system with variable gain electrodes

Abstract: Technologies are presented for selecting an electrode gain value for applying electricity to control a combustion reaction. F or example, a system can include one or more electrodes, an electrode gain selector configured to select an operative electrode gain value for the one or more electrodes, and a power supply operatively coupled to the one or more electrodes. The power supply can be configured to apply the electricity to the combustion reaction via the one or more electrodes at the operative electrode gain value.

Capacitive touch screen and single layer wiring electrode array

Abstract: Disclosed are a capacitive touch screen and a single layer wiring electrode array. The single layer wiring electrode array includes capacitive regions and wiring regions located on one plane. Wires in the wiring regions are zigzag-shaped or wave-shaped. The capacitive touch screen includes a substrate; a single layer wiring electrode array disposed over the substrate, wherein the single layer wiring electrode array includes capacitive regions and wiring regions located on one plane and wires in the wiring region are zigzag-shaped or wave-shaped; and control ports for connecting to one or more integrated circuits, wherein the wires in the wiring regions are connected to the control ports respectively. The single layer wiring electrode array and the capacitive touch screen lower the fabrication cost and improve the display effects.

Close-coupled step-up voltage converter and electrode for a combustion system

Abstract: A high voltage signal is output to an electrode, which applies electrical energy to a combustion reaction. The high voltage signal can be output by a step-up voltage converter to the electrode via a close electrical coupling. The close electrical coupling is configured to electrically isolate the high voltage signal from a human-accessible volume.

Combustion system with a grid switching electrode

Abstract: A high voltage can be applied to a combustion reaction to enhance or otherwise control the combustion reaction. The high voltage is switched on or off by a grid electrode interposed between a high voltage electrode assembly and the combustion reaction.

Characteristics of electrode impedance and stimulation efficacy of a chronic cortical implant using novel annulus electrodes in rat motor cortex

Abstract: Objective. Cortical neural prostheses with implanted electrode arrays have been used to restore compromised brain functions but concerns remain regarding their long-term stability and functional performance. Approach. Here we report changes in electrode impedance and stimulation thresholds for a custom-designed electrode array implanted in rat motor cortex for up to three months. Main Results. The array comprises four 2000??m long electrodes with a large annular stimulating surface (7860?15700??m2) displaced from the penetrating insulated tip. Compared to pre-implantation in vitro values there were three phases of impedance change: (1) an immediate large increase of impedance by an average of two-fold on implantation; (2) a period of continued impedance increase, albeit with considerable variability, which reached a peak at approximately four weeks post-implantation and remained high over the next two weeks; (3) finally, a period of 5?6 weeks when impedance stabilized at levels close to those seen immediately post-implantation. Impedance could often be temporarily decreased by applying brief trains of current stimulation, used to evoke motor output. The stimulation threshold to induce observable motor behaviour was generally between 75?100??A, with charge density varying from 48?128??C cm?2, consistent with the lower current density generated by electrodes with larger stimulating surface area. No systematic change in thresholds occurred over time, suggesting that device functionality was not compromised by the factors that caused changes in electrode impedance. Significance. The present results provide support for the use of annulus electrodes in future applications in cortical neural prostheses.

Unwrapped 2D view of a stimulation lead with complex electrode array geometry

Abstract: The disclosure is directed to programming implantable stimulators to deliver stimulation energy via one or more implantable leads having complex electrode array geometries. The disclosure also contemplates guided programming to select electrode combinations and parameter values to support efficacy. The techniques may be applied to a programming interface associated with a clinician programmer, a patient programmer, or both. A user interface permits a user to view electrodes from different perspectives relative to the lead. For example, the user interface provides a side view of a lead and a cross-sectional view of the lead. The user interface may include an axial control medium to select and/or view electrodes at different axial positions along the length of a lead, and a rotational control medium to select and/or view electrodes at different angular positions around a circumference of the lead.

Overview of significant examples of electrochemical sensor arrays designed for detection of nitric oxide and relevant species in a biological environment.

Abstract: Ultramicroelectrode sensor arrays in which each electrode, or groups of electrodes, are individually addressable are of particular interest for detection of several species concomitantly, by using specific sensing chemistry for each analyte, or for mapping of one analyte to achieve spatio–temporal analysis. Microfabrication technology, for example photolitography, is usually used for fabrication of these arrays. The most widespread geometries produced by photolithography are thin-film microdisc electrode arrays with different electrode distributions (square, hexagonal, or random). In this paper we review different electrochemical sensor arrays developed to monitor, in vivo, NO levels produced by cultured cells or sliced tissues. Simultaneous detection of NO and analytes interacting with or released at the same time as NO is also discussed.

Capacitive Sensor with Reduced Noise

Abstract: A capacitive touch sensor of the type employing adjacent drive and sense electrodes, in which an additional sense electrode Y1 is provided as well as the conventional drive electrode Xn and sense electrode Y0. The drive and two sense electrodes are arranged on the bottom side of a dielectric panel, the top side providing—a sensing surface to be touched by a user's finger or a stylus. The additional sense electrode is positioned on the underside of the dielectric panel so that it is shielded from the drive electrode by the conventional sense electrode. As a consequence, the conventional sense electrode is much more sensitive to the proximity of the finger or stylus than the additional sense electrode which primarily registers noise. The signal collected form the additional sense electrode is then subtracted from the signal collected from the conventional sense electrode, thereby to cancel noise. Another design provides similar functionality with a capacitive touch sensor of the type employing single-ended electrodes.

Design of Underactuated Steerable Electrode Arrays for Optimal Insertions

Abstract: This paper addresses the design of wire actuated steerable electrode arrays for optimal insertions in cochlear implant surgery. These underactuated electrode arrays are treated as continuum robots which have an embedded actuation strand inside their flexible medium. By pulling on the actuation strand, an electrode array assumes a minimum-energy shape. The problems of designing optimal actuation strand placement are addressed in this paper. Based on the elastic modeling of the steerable electrode arrays proposed in this paper, an analytical solution of the strand placement is solved to minimize the shape discrepancy between a bent electrode array and a given target curve defined by the anatomy. Using the solved strand placement inside the steerable electrode array, an optimized insertion path planning with robotic assistance is proposed to execute the insertion process. Later, an optimization algorithm is presented to minimize the shape discrepancy between an inserted electrode array and a given target curve during the whole insertion process. Simulations show a steerable electrode array bending using the elastic model and robot insertion path planning with optimized strand placement. Two experiments have been conducted to validate the elastic model and algorithms.

Fabrication of a flexible penetrating microelectrode array for use on curved surfaces of neural tissues

Abstract: Conventionally, invasive neural microelectrodes for recording neuronal signals or stimulating the nervous system have been fabricated based on silicon substrate mainly due to well-established manufacturing processes. However, these silicon-based microelectrode devices have an issue of mechanical stability caused by the absence of flexibility when implanted onto curved surfaces of tissues. In this paper, a flexible and penetrating microelectrode array, a hybrid structure composed of silicon and elastomer, was devised and fabricated by bulk micromachining technologies. The structure uses individual silicon needles as independent electrodes in a square array and polydimethysiloxane (PDMS) as a base to support the needles. The dimensions of the electrode array and the needles are adjustable, depending on the number of needles, the pitch between the needles and the targeted penetration depth of the neural tissue. For mechanical characterization, the adhesion between PDMS and silicon was evaluated and the flexibility and integrity of the fabricated structure were investigated through flexural test and insertion test. Also, the electrochemical impedance spectroscopy of the electrodes was measured. The results suggest that the proposed microelectrode array is promising for use in neuronal recording and stimulation over curved surfaces such as cortical surface and peripheral nerves with larger curvatures.

Electrical stimulation with a penetrating optic nerve electrode array elicits visuotopic cortical responses in cats

Abstract: Objective. A visual prosthesis based on penetrating electrode stimulation within the optic nerve (ON) is a potential way to restore partial functional vision for blind patients. We investigated the retinotopic organization of ON stimulation and its spatial resolution. Approach. A five-electrode array was inserted perpendicularly into the ON or a single electrode was advanced to different depths within the ON (~1–2 mm behind the eyeball, 13 cats). A sparse noise method was used to map ON electrode position and the visual cortex. Cortical responses were recorded by a 5 × 6 array. The visuotopic correspondence between the retinotopic position of the ON electrode was compared with the visual evoked cortical map and the electrical evoked potentials elicited in response to ON stimulation. Main results. Electrical stimulation with penetrating ON electrodes elicited cortical responses in visuotopographically corresponding areas of the cortex. Stimulation of the temporal side of the ON elicited cortical responses corresponding to the central visual field. The visual field position shifted from the lower to central visual field as the electrode penetrated through the depth of the ON. A spatial resolution of ~ 2° to 3° within a limited cortical visuotopic representation could be obtained by this approach. Significance. Visuotopic electrical stimulation with a relatively fine spatial resolution can be accomplished using penetrating electrodes implanted at multiple sites and at different depths within the ON just behind the globe. This study also provides useful experimental data for the design of electrode density and the distribution of penetrating ON electrodes for a visual prosthesis.