scholarly journals Effects of Pulse Shape and Polarity on Sensitivity to Cochlear Implant Stimulation: A Chronic Study in Guinea Pigs

2016 ◽  
pp. 133-142 ◽  
Author(s):  
Olivier Macherey ◽  
Yves Cazals
Keyword(s):  
Cochlear Implant ◽  
Guinea Pigs ◽  
Pulse Shape ◽  
Chronic Study

scholarly journals Influence of Cochleostomy and Cochlear Implant Insertion on Drug Gradients following Intratympanic Application in Guinea Pigs

2013 ◽  
Vol 18 (5) ◽  
pp. 307-316 ◽  
Author(s):  
E.B. King ◽  
J.J. Hartsock ◽  
S.J. O'Leary ◽  
A.N. Salt
Keyword(s):  
Cochlear Implant ◽  
Guinea Pigs

scholarly journals Perilymph pharmacokinetics of marker applied through a cochlear implant in guinea pigs

PLoS ONE ◽  
2017 ◽  
Vol 12 (8) ◽  
pp. e0183374 ◽  
Author(s):  
Alec Salt ◽  
Jared Hartsock ◽  
Ruth Gill ◽  
Daniel Smyth ◽  
Jonathon Kirk ◽  
...  
Keyword(s):  
Cochlear Implant ◽  
Guinea Pigs

Extended use of systemic steroid is beneficial in preserving hearing in guinea pigs after cochlear implant

2016 ◽  
Vol 136 (12) ◽  
pp. 1213-1219 ◽  
Author(s):  
Yoon Chan Rah ◽  
Min Young Lee ◽  
Shin Hye Kim ◽  
Doo Hee Kim ◽  
Hayden Eastwood ◽  
...  
Keyword(s):  
Cochlear Implant ◽  
Guinea Pigs ◽  
Systemic Steroid

Auditory Cortical Images of Cochlear-Implant Stimuli: Dependence on Electrode Configuration

2002 ◽  
Vol 87 (1) ◽  
pp. 478-492 ◽  
Author(s):  
Julie Arenberg Bierer ◽  
John C. Middlebrooks
Keyword(s):  
Cochlear Implant ◽  
Guinea Pigs ◽  
Common Ground ◽  
Dynamic Range ◽  
Primary Auditory Cortex ◽  
Stimulus Level ◽  
Electrode Configuration ◽  
Spatiotemporal Pattern ◽  
Active Electrode ◽  
Sensitive Site

This study examines patterns of auditory cortical activity elicited by single-pulse cochlear implant stimuli that vary in electrode configuration, cochlear place of stimulation, and stimulus level. Recordings were made from the primary auditory cortex (area A1) of ketamine-anesthetized guinea pigs. The spatiotemporal pattern of neural spike activity was measured simultaneously across 16 cortical locations spanning approximately 2–3 octaves of the tonotopic axis. Such a pattern, averaged over 40 presentations of any particular stimulus, was defined as the “cortical image” of that stimulus. Acutely deafened guinea pigs were implanted with a 6-electrode animal version of the 22-electrode Nucleus banded electrode array (Cochlear). Cochlear electrode configurations consisted of monopolar (MP), bipolar (BP + N) with N inactive electrodes between the active and return electrodes (0 ≤ N ≤ 4), tripolar (TP) with one active electrode and two flanking return electrodes, and common ground (CG) with one active electrode and as many as five return electrodes. Cortical images typically showed a focus of maximum spike probability and minimum latency. Spike probabilities tended to decrease, and latencies tended to increase, with increasing cortical distance from that focus. Cortical images of TP stimuli were the most spatially compact, followed by BP + N images, and then MP images, which were the broadest. Images of CG stimuli were rather variable across animals and stimulus channels. The locations of cortical images shifted systematically from caudal to rostral as the cochlear place of stimulation changed from basal to apical. At the most sensitive cortical site for each condition, the dynamic ranges over which spike rates increased with increased current level were restricted to about 1–2 dB, regardless of configuration. Dynamic ranges tended to increase with increasing cortical distance from the most sensitive site. Electrode configurations that produced compact cortical images (e.g., TP and BP + 0) showed the greatest range of thresholds within each cortical image and the largest dynamic range at cortical sites removed from the most sensitive site.

scholarly journals Mimic Cochlear Implant Surgery-Induced Cochlear Infection Fails to Further Damage Auditory Pathway in Deafened Guinea Pigs

2018 ◽  
Vol 24 ◽  
pp. 5448-5456 ◽  
Author(s):  
Zhao Han ◽  
Chengjin Wang ◽  
Yuyan Gu ◽  
Ning Cong ◽  
Rui Ma ◽  
...  
Keyword(s):  
Cochlear Implant ◽  
Guinea Pigs ◽  
Auditory Pathway ◽  
Implant Surgery ◽  
Cochlear Implant Surgery

Solar Flare Energetic Neutral Emission Measurements in the Project Coronas-I

1994 ◽  
Vol 144 ◽  
pp. 635-639
Author(s):  
J. Baláž ◽  
A. V. Dmitriev ◽  
M. A. Kovalevskaya ◽  
K. Kudela ◽  
S. N. Kuznetsov ◽  
...  
Keyword(s):  
Solar Flare ◽  
Energy Range ◽  
Gamma Rays ◽  
Pulse Shape ◽  
Gamma Ray ◽  
Pulse Shape Discrimination ◽  
Shape Discrimination ◽  
Solar Neutron ◽  
Low Altitude

AbstractThe experiment SONG (SOlar Neutron and Gamma rays) for the low altitude satellite CORONAS-I is described. The instrument is capable to provide gamma-ray line and continuum detection in the energy range 0.1 – 100 MeV as well as detection of neutrons with energies above 30 MeV. As a by-product, the electrons in the range 11 – 108 MeV will be measured too. The pulse shape discrimination technique (PSD) is used.

Investigation of the relaxant effects of propofol on ovalbumin-induced asthma in guinea pigs

2006 ◽  
pp. 1
Author(s):  
I. Bagcivan ◽  
O. Cevit ◽  
M. K. Yildirim ◽  
S. Gursoy ◽  
S. Yildirim ◽  
...  
Keyword(s):  
Guinea Pigs

Hepatocyte Alterations in Guinea Pigs FED Polychlorinated Biphenyls (PCBs), Dibenzodioxins (PCDD), AND DIBENZOFURANS (PCDF)

1982 ◽  
Vol 40 ◽  
pp. 56-57
Author(s):  
J. N. Turner ◽  
D. N. Collins
Keyword(s):  
Guinea Pigs ◽  
Room Temperature ◽  
Dose Group ◽  
Methyl Cellulose ◽  
Uranyl Acetate ◽  
Target Organ ◽  
Office Building ◽  
Lead Citrate ◽  
Control Groups ◽  
Cooling Fluid

A fire involving an electric service transformer and its cooling fluid, a mixture of PCBs and chlorinated benzenes, contaminated an office building with a fine soot. Chemical analysis showed PCDDs and PCDFs including the highly toxic tetra isomers. Guinea pigs were chosen as an experimental animal to test the soot's toxicity because of their sensitivity to these compounds, and the liver was examined because it is a target organ. The soot was suspended in 0.75% methyl cellulose and administered in a single dose by gavage at levels of 1,10,100, and 500mgm soot/kgm body weight. Each dose group was composed of 6 males and 6 females. Control groups included 12 (6 male, 6 female) animals fed activated carbon in methyl cellulose, 6 males fed methyl cellulose, and 16 males and 10 females untreated. The guinea pigs were sacrificed at 42 days by suffocation in CO2. Liver samples were immediately immersed and minced in 2% gluteraldehyde in cacadylate buffer at pH 7.4 and 4°C. After overnight fixation, samples were postfixed in 1% OsO4 in cacodylate for 1 hr at room temperature, embedded in epon, sectioned and stained with uranyl acetate and lead citrate.

Glycogen in guinea pig neutrophils: Ultrastructural study of neutrophils at the intradermal site of BCG injection

1983 ◽  
Vol 41 ◽  
pp. 726-727
Author(s):  
Corazon D. Bucana
Keyword(s):  
Bone Marrow ◽  
Guinea Pig ◽  
Electron Density ◽  
Peritoneal Cavity ◽  
Ultrastructural Study ◽  
Guinea Pigs ◽  
Random Distribution ◽  
Glycogen Content ◽  
Polymorphonuclear Neutrophils ◽  
Ultrastructural Studies

In the circulating blood of man and guinea pigs, glycogen occurs primarily in polymorphonuclear neutrophils and platelets. The amount of glycogen in neutrophils increases with time after the cells leave the bone marrow, and the distribution of glycogen in neutrophils changes from an apparently random distribution to large clumps when these cells move out of the circulation to the site of inflammation in the peritoneal cavity. The objective of this study was to further investigate changes in glycogen content and distribution in neutrophils. I chose an intradermal site because it allows study of neutrophils at various stages of extravasation.Initially, osmium ferrocyanide and osmium ferricyanide were used to fix glycogen in the neutrophils for ultrastructural studies. My findings confirmed previous reports that showed that glycogen is well preserved by both these fixatives and that osmium ferricyanide protects glycogen from solubilization by uranyl acetate.I found that osmium ferrocyanide similarly protected glycogen. My studies showed, however, that the electron density of mitochondria and other cytoplasmic organelles was lower in samples fixed with osmium ferrocyanide than in samples fixed with osmium ferricyanide.

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