scholarly journals Selective electrical stimulation with currentfield modulation

2021 ◽  
Vol 7 (2) ◽  
pp. 803-806
Author(s):  
Halldór Kárason ◽  
Óskar Pilkington ◽  
Thordur Helgason
Keyword(s):  
Electrical Stimulation ◽  
Electrode Array ◽  
Single Pulse ◽  
Treatment Modalities ◽  
Electrode Arrays ◽  
Current Field ◽  
Temporal Precision ◽  
Specific Stimulation ◽  
Field Modulation ◽  
Electrical Stimulator

Abstract Selective electrical stimulation using a multielectrode array is a promising technique that can potentially bring electrical stimulation treatment modalities a step forward. A microcontroller-controlled electrical stimulator system delivering a single pulse was designed, suitable for current-field modulation. The goal is to make electrical stimulation with surface electrodes more specific. A graphical user interface (GUI) was developed to control stimulation parameters and current-field within a multi-electrode array wirelessly. The stimulator generates arbitrary biphasic waveforms with a 5-bit resolution and high temporal precision (<10 μs) and was demonstrated to stimulate posterior lumbar root fibers in transcutaneous spinal cord stimulation (tSCS) treatment selectively. Current-field modulation throughout a sixteen-electrode array was achieved. The system has the goal to improve control of stimulation conditions in electrophysiological studies and time-dependent and site-specific stimulation patterns for neuromodulation applications. A novel feature is the current-field modulation ability of the stimulator for surface electrode arrays.

Technical Approach for Reanimation of the Chronically Denervated Larynx by Means of Functional Electrical Stimulation

1994 ◽  
Vol 103 (9) ◽  
pp. 705-712 ◽  
Author(s):  
David L. Zealear ◽  
Cheryl L. Rainey ◽  
Tetsuya Tanabe ◽  
Matthew L. Jerles ◽  
Garrett D. Herzon
Keyword(s):  
Electrical Stimulation ◽  
Functional Electrical Stimulation ◽  
Vocal Fold ◽  
Hot Spot ◽  
Electrode Array ◽  
Electrode Arrays ◽  
Denervated Muscle ◽  
Alternative Approach ◽  
Bilateral Vocal Fold Paralysis ◽  
Posterior Cricoarytenoid

Functional electrical stimulation (FES) of the posterior cricoarytenoid (PCA) muscle to produce vocal fold abduction offers an alternative approach to current surgical therapies for bilateral vocal fold paralysis. The purpose of this study was to characterize the application of FES to chronically denervated PCA muscles. Specific goals were to develop a stimulus delivery system for the PCA muscle, determine a practical means of implantation, and identify stimulus parameters effective in activating chronically denervated muscle. Seventeen dogs were implanted with planar electrode arrays 3 months after unilateral recurrent laryngeal nerve resection. A nail-bed electrode array allowed discrete activation of the PCA muscle and gave the greatest abductions, with minimal charge dissipation. Muscle mapping revealed hot-spot regions on the PCA muscle surface, in which stimulation produced maximum abduction. A conservative stimulus paradigm effective in activating chronically denervated muscle was a 1-second pulse train of 2-millisecond-duration pulses, delivered at a tetanizing frequency of 30 Hz and an amplitude of 4 to 14 mA.

scholarly journals Electrophysiological investigation of intact retina with soft printed organic neural interface

2021 ◽  
Author(s):  
Ieva Vebraite-Adereth ◽  
Moshe David-Pur ◽  
David Rand ◽  
Eric Glowacki ◽  
Yael Hanein
Keyword(s):  
Electrical Stimulation ◽  
Ex Vivo ◽  
Electrode Array ◽  
Carbon Electrodes ◽  
Natural Image ◽  
Neural Firing ◽  
Electrode Arrays ◽  
Electrical Recording ◽  
Research Activities

Abstract Objective. Understanding how the retina converts a natural image or an electrically stimulated one into neural firing patterns is the focus of on-going research activities. Ex vivo, the retina can be readily investigated using multi electrode arrays. However, multi electrode array recording and stimulation from an intact retina (in the eye) has been so far insufficient. Approach. In the present study, we report new soft carbon electrode arrays suitable for recording and stimulating neural activity in an intact retina. Screen-printing of carbon ink on 20 µm polyurethane (PU) film was used to realize electrode arrays with electrodes as small as 40 µm in diameter. Passivation was achieved with a holey membrane, realized using laser drilling in a thin (50 µm) PU film. Plasma polymerized EDOT was used to coat the electrode array to improve the electrode specific capacitance. Chick retinas, embryonic stage day 13, both ex-planted and intact inside an enucleated eye, were used. Main results. A novel fabrication process based on printed carbon electrodes was developed and yielded high capacitance electrodes on a soft substrate. Ex vivo electrical recording of retina activity with carbon electrodes is demonstrated. With the addition of organic photo-capacitors, simultaneous photo-electrical stimulation and electrical recording was achieved. Finally, electrical activity recordings from an intact chick retina (inside enucleated eyes) were demonstrated. Both photosensitive retinal ganglion cell responses and spontaneous retina waves were recorded and their features analyzed. Significance. Results of this study demonstrated soft electrode arrays with unique properties, suitable for simultaneous recording and photo-electrical stimulation of the retina at high fidelity. This novel electrode technology opens up new frontiers in the study of neural tissue in vivo.

Tissue reactions to long-term electrical stimulation of the cerebellum in monkeys

1977 ◽  
Vol 47 (3) ◽  
pp. 366-379 ◽  
Author(s):  
W. Jann Brown ◽  
Thomas L. Babb ◽  
Henry V. Soper ◽  
Jeffrey P. Lieb ◽  
Carlos A. Ottino ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Charge Density ◽  
Purkinje Cells ◽  
Molecular Layer ◽  
Electrode Array ◽  
Electrode Arrays ◽  
Human Cerebellum ◽  
A Charge ◽  
Tissue Reactions ◽  
Stimulation Of

✓ Light and electron microscopic analyses were carried out on the stimulated and unstimulated paravermal cortices of six rhesus monkeys that had electrodes implanted on their cerebella for 2 months. The electrodes and the stimulation regime (10 p.p.s.: 8 min on, 8 min off) were similar to those used to stimulate the human cerebellum for treatment of certain neurological disorders. Mere presence of the electrode array in the posterior fossa for 2 months resulted in some meningeal thickening, attenuation of the molecular layer, and loss of Purkinje cells immediately beneath the electrode array. There was no evidence of scarring. After 205 hours of stimulation (7.38 × 106 pulses) over 18 days, a charge of 0.5 µC/ph or estimated charge density of 7.4 µC/sq cm/ph resulted in no damage to the cerebellum attributable to electrical stimulation per se. Such a charge/phase is about five times the threshold for evocation of cerebellar efferent activity, and might be considered “safe” for stimulation of human cerebellum. Charge density/phase and charge/phase were directly related to increased cerebellar injury in the six other cerebellar cortices stimulated. Leptomeningeal thickening increased with increased charge density. Injury included severe molecular layer attenuation, ongoing destruction of Purkinje cells, gliosis, ongoing degeneration of myelinated axons, collagen intrusion, and increased levels of local polysaccharides. In all cases, even with damage that destroyed all conducting elements beneath the electrodes, there was no damage further than 1 to 2 mm from the edges of the electrode arrays.

Automatic control of grasping strength for functional electrical stimulation in forearm movements via electrode arrays

2018 ◽  
Vol 66 (12) ◽  
pp. 1027-1036 ◽  
Author(s):  
Christina Salchow-Hömmen ◽  
Till Thomas ◽  
Markus Valtin ◽  
Thomas Schauer
Keyword(s):  
Electrical Stimulation ◽  
Functional Electrical Stimulation ◽  
Motion Tracking ◽  
Inertial Sensors ◽  
Electrode Array ◽  
Electrode Arrays ◽  
Reach And Grasp ◽  
Automatic Adaptation ◽  
Virtual Electrodes ◽  
Relative Change

Abstract The generation of precise hand movements with functional electrical stimulation (FES) via surface electrodes on the forearm faces several challenges. Besides the biomechanical complexity and the required selectivity, the rotation of the forearm during reach-and-grasp tasks leads to a relative change between the skin and underlying tissue, resulting in a varying FES response. We present a new method for automatic adaptation of virtual electrodes (size, position) and stimulation intensity in an electrode array to guarantee a secure grasp during forearm movements. The method involves motion tracking of arm and hand with inertial sensors. This enables the estimation of grasping strength when using elastic objects. Experiments in healthy volunteers revealed that our method allows generating a strong, stable grasp force regardless of the rotational state of the forearm.

scholarly journals Single-pulse electrical stimulation methodology in freely moving rat

2021 ◽  
Vol 353 ◽  
pp. 109092
Author(s):  
Eloïse Gronlier ◽  
Estelle Vendramini ◽  
Julien Volle ◽  
Agata Wozniak-Kwasniewska ◽  
Noelia Antón Santos ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Single Pulse ◽  
Freely Moving

scholarly journals The Importance of Intraoperative Plain Radiographs during Cochlear Implant Surgery in Patients with Normal Anatomy

2021 ◽  
Vol 11 (9) ◽  
pp. 4144
Author(s):  
Ohad Cohen ◽  
Jean-Yves Sichel ◽  
Chanan Shaul ◽  
Itay Chen ◽  
J. Thomas Roland ◽  
...  
Keyword(s):  
Cochlear Implant ◽  
Electrode Array ◽  
Cost Effective ◽  
X Rays ◽  
Normal Anatomy ◽  
Electrode Arrays ◽  
Plain Radiographs ◽  
Hearing Function ◽  
Tertiary Center ◽  
Cochlear Implant Surgery

Although malpositioning of the cochlear implant (CI) electrode array is rare in patients with normal anatomy, when occurring it may result in reduced hearing outcome. In addition to intraoperative electrophysiologic tests, imaging is an important modality to assess correct electrode array placement. The purpose of this report was to assess the incidence and describe cases in which intraoperative plain radiographs detected a malpositioned array. Intraoperative anti-Stenver’s view plain X-rays are conducted routinely in all CI surgeries in our tertiary center before awakening the patient and breaking the sterile field. Data of patients undergoing 399 CI surgeries were retrospectively analyzed. A total of 355 had normal inner ear and temporal bone anatomy. Patients with intra or extracochlear malpositioned electrode arrays demonstrated in the intraoperative X-ray were described. There were four cases of electrode array malposition out of 355 implantations with normal anatomy (1.1%): two tip fold-overs, one extracochlear placement and one partial insertion. All electrodes were reinserted immediately; repeated radiographs were normal and the patients achieved good hearing function. Intraoperative plain anti-Stenver’s view X-rays are valuable to confirm electrode array location, allowing correction before the conclusion of surgery. These radiographs are cheaper, faster, and emit much less radiation than other imaging options, making them a viable cost-effective tool in patients with normal anatomy.

scholarly journals Effects of electrical stimulation on isolated rodent gastric smooth muscle cells evaluated via a joint computational simulation and experimental approach

2009 ◽  
Vol 297 (4) ◽  
pp. G672-G680 ◽  
Author(s):  
P. Du ◽  
S. Li ◽  
G. O'Grady ◽  
L. K. Cheng ◽  
A. J. Pullan ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Electrical Stimulation ◽  
Pulse Train ◽  
Pulse Width ◽  
Computational Simulation ◽  
Minimum Energy ◽  
Experimental Studies ◽  
Single Pulse ◽  
Plateau Phase ◽  
Wide Range

Gastric electrical stimulation (GES) involves the delivery of electrical impulses to the stomach for therapeutic purposes. New GES protocols are needed that are optimized for improved motility outcomes and energy efficiency. In this study, a biophysically based smooth muscle cell (SMC) model was modified on the basis of experimental data and employed in conjunction with experimental studies to define the effects of a large range of GES protocols on individual SMCs. For the validation studies, rat gastric SMCs were isolated and subjected to patch-clamp analysis during stimulation. Experimental results were in satisfactory agreement with simulation results. The results define the effects of a wide range of GES parameters (pulse width, amplitude, and pulse-train frequency) on isolated SMCs. The minimum pulse width required to invoke a supramechanical threshold response from SMCs (defined at −30 mV) was 65 ms (at 250-pA amplitude). The minimum amplitude required to invoke this threshold was 75 pA (at 1,000-ms pulse width). The amplitude of the invoked response beyond this threshold was proportional to the stimulation amplitude. A high-frequency train of stimuli (40 Hz; 10 ms, 150 pA) could invoke and maintain the SMC plateau phase while requiring 60% less power and accruing ∼30% less intracellular Ca2+ concentration during the plateau phase than a comparable single-pulse protocol could in a demonstrated example. Validated computational simulations are an effective strategy for efficiently identifying effective minimum-energy GES protocols, and pulse-train protocols may also help to reduce the power consumption of future GES devices.

scholarly journals Sleep modulates cortical connectivity and excitability in humans: Direct evidence from neural activity induced by single-pulse electrical stimulation

2015 ◽  
Vol 36 (11) ◽  
pp. 4714-4729 ◽  
Author(s):  
Kiyohide Usami ◽  
Riki Matsumoto ◽  
Katsuya Kobayashi ◽  
Takefumi Hitomi ◽  
Akihiro Shimotake ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Neural Activity ◽  
Direct Evidence ◽  
Single Pulse ◽  
Cortical Connectivity

Precise Alignment of Micromachined Electrode Arrays With V1 Functional Maps

2007 ◽  
Vol 97 (5) ◽  
pp. 3781-3789 ◽  
Author(s):  
Ian Nauhaus ◽  
Dario L. Ringach
Keyword(s):  
Receptive Field ◽  
Electrode Array ◽  
Theoretical Models ◽  
Orientation Tuning ◽  
Feedback Signal ◽  
Electrode Arrays ◽  
Tuning Curves ◽  
Alignment Procedure ◽  
Receptive Field Properties ◽  
Orientation Maps

Recent theoretical models of primary visual cortex predict a relationship between receptive field properties and the location of the neuron within the orientation maps. Testing these predictions requires the development of new methods that allow the recording of single units at various locations across the orientation map. Here we present a novel technique for the precise alignment of functional maps and array recordings. Our strategy consists of first measuring the orientation maps in V1 using intrinsic optical imaging. A micromachined electrode array is subsequently implanted in the same patch of cortex for electrophysiological recordings, including the measurement of orientation tuning curves. The location of the array within the map is obtained by finding the position that maximizes the agreement between the preferred orientations measured electrically and optically. Experimental results of the alignment procedure from two implementations in monkey V1 are presented. The estimated accuracy of the procedure is evaluated using computer simulations. The methodology should prove useful in studying how signals from the local neighborhood of a neuron, thought to provide a dominant feedback signal, shape the receptive field properties in V1.

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