1,721,051 research outputs found
Fascicular nerve stimulation and recording using a novel double-aisle regenerative electrode
No full textObjective. As artificial prostheses become more refined, they are most often used as a therapeutic option for hand amputation. By contrast to extra- or intraneural interfaces, regenerative nerve electrodes are designed to enable electrical interfaces with regrowing axonal bundles of injured nerves, aiming to achieve high selectivity for recording and stimulation. However, most of the developed designs pose an obstacle to the regrowth mechanisms due to low transparency and cause impairment to the nerve regeneration. Approach. Here we present the double-aisle electrode, a new type of highly transparent, non-obstructive regenerative electrode. Using a double-side thin-film polyimide planar multi-contact electrode, two nerve fascicles can regenerate without physical impairment through two electrically isolated aisles. Main results. We show that this electrode can be used to selectively record and stimulate fascicles, acutely as well as chronically, and allow regeneration in nerve gaps of several millimeters without impairment. Significance. This multi-aisle regenerative electrode may be suitable for neuroprosthetic applications, such as prostheses, for the restoration of hand function after amputation or severe nerve injuries. © 2017 IOP Publishing Ltd
Neural prosthesis for motor function restoration in upper limb extremity
No full textRestoration of motor function in cases of peripheral nerve injury is a challenging problem. Although peripheral nerves do regenerate, the time required for peripheral nerves to regenerate often causes atrophy to occur in the muscles before they can be re-innervated. This paper presents a solution through proximal recording of nerve signals and distal muscle stimulation. A fully implantable hardware architecture is described that can be operated by means of inductive power and MICS band data transmission schemes. Preliminary experiments and validation studies are reported with non-human primates based on recordings in the median nerve, stimulation of hand muscles, and task decoding and classification. This approach shows promise in creating a neural prosthesis capable of restoring hand movements in patients with upper limb peripheral nerve injuries
A three-dimensional self-opening intraneural peripheral interface (SELINE)
No full textObjective. In this study we present the development and testing in a rat model of the self-opening neural interface (SELINE), a novel flexible peripheral neural interface. Approach. This polyimide-based electrode has a three-dimensional structure that provides an anchorage system to the nerve and confers stability after implant. This geometry has been achieved by means of the plastic deformation of polyimide. Mechanical and electrochemical characterizations have been performed to prove the integrity of the electrode with very good results. Functionality of SELINEs for fascicular stimulation has been tested during in vivo acute experiments in the rat. Chronic implants were made to test the biocompatibility of the device. Main results. Results showed that SELINEs significantly improve mechanical anchorage to the nerve. Stimulation stability is considerably enhanced compared to common planar transversal electrodes and stimulation selectivity is increased for some motor fascicles. Chronic experimental results showed that SELINEs neither produce changes in the fascicular organization of sciatic nerves nor signs of nerve degeneration. Significance. The presented three-dimensional electrode provides an effective anchorage system to the nervous tissue that can improve the stability of the implant for acute and chronic studies. © 2015 IOP Publishing Ltd
An intrafascicular electrode with integrated amplifiers for peripheral nerve recording
No full textThin-film longitudinal intrafascicular electrodes (tf-LIFE) are widely used for peripheral nerve recordings. tf-LIFEs are also promising electrodes for neural signal acquisition in future peripheral nerve prostheses. However, common mode signal interference, and electrical artifacts originating from long wire leads and wire movement are known problems encountered when using such electrodes, which lead to degradation in the recording quality. Here, we report an active tf-LIFE electrode implemented by integrating a neural amplifier chip die in close proximity to a tf-LIFE electrode. Consuming only 1mW and measuring 37 mm×7.2 mm×2.4 mm, this active tf-LIFE electrode creates a reliable connection and considerably shortens the distance between the electrode site and neural amplifier. This active electrode has demonstrated repeatable in-vivo recordings of compound action potentials from the rat sciatic nerve. Our results show that this electrode is suitable for repeated in-vivo recordings of compound action potentials from nerves in applications such as peripheral and visceral nerve interfaces that require low-noise stable nerve recordings. © 2015 IEEE
A low-cost, 61-channel μeCoG array for use in rodents
No full textMicro-Electrocorticography (μECoG) offers a minimally invasive, high resolution interface with large areas of cortex. A wide variety of μECoG designs have been developed and customized [1]-[4], including active, multiplexed arrays [5] and arrays on dissolving substrates for increased conformal contact [6]. However, designing and fabricating customized μECoG arrays requires access to microfabrication facilities, which many neuroscience labs do not have. Microfabrication is also typically labor intensive and expensive. Commercial μECoG arrays with 64 electrodes and coarser dimensions cost approximately 26 when ordered in quantities of 100, with the cost per electrode increasing slightly when lower quantities are ordered. Fine pitch wires minimize the size of the interconnections, enabling chronic implantation in rodents. In-house post-processing of the fabricated μECoG arrays added optional electrode coatings, such as platinum black, to reduce the electrode impedance. Our electrode design and manufacturing process dramatically improves the accessibility and reduces the cost of high-volume, high-resolution neuroscience. © 2015 IEEE
The Efficacy of a Dietary Supplement with Carnosine and Hibiscus Sabdariffa L. (AqualiefTM) in Patients with Xerostomia: a Randomized, Placebo-Controlled, Double-Blind Trial
No full textThe purpose of this study was to test the safety and efficacy of AqualiefTM in patients affected by xerostomia. The main ingredients of AqualiefTM are carnosine and dried calyces of Hibiscus sabdariffa L. (karkadè) for their buffering effect at pH 7 as well as for their antioxidant, antimicrobial and lenitive properties. In a Randomized, Placebo-Controlled, Double-Blind Trial, sixty patients with xerostomia (RTOG/EORTC grade 1-2) were randomly assigned to receive either placebo, or AqualiefTM tablets (three times/day after meals) for 6 consecutive days. A questionnaire was used to evaluate dry mouth symptoms before and after 6 days of AqualiefTM or placebo application. Unstimulated and stimulated salivary flow rates and pH were measured before and after application. Treatment with AqualiefTM for 6 days induced a significant increase in saliva pH from 6.2 ± 0.5 to 6.4 ± 0.6 (P < 0.05) while placebo was ineffective (from 6.2 ± 0.5 to 6.3 ± 0.5). AqualiefTM also induced a significant increase in the pH of stimulated saliva from 6.3 ± 0.5 to 6.6 ± 0.5 (P < 0.01). Placebo was ineffective also in this setting (from 6.2 ± 0.5 to 6.3 ± 0.5). Besides an expected normalization of the saliva pH value, AqualiefTM treatment for 6 days greatly increased (56%, P < 0.0001) saliva production. Placebo induced a 19% increase (P < 0.05), which was likely due to mechanical stimulation. AqualiefTM also increased stimulated saliva production (27% increase with respect to day 0, P < 0.05), while placebo was ineffective. AqualiefTM was effective in regulating the saliva pH, in increasing saliva production and improving dry mouth symptoms in xerostomic patients
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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