Implanted Cochlear Prosthesis Analogue In Primates

1980 ◽  
Vol 88 (4) ◽  
pp. 477-485 ◽  
Author(s):  
Thomas J. Balkany ◽  
Robert E. Mischke ◽  
James D. Pauley ◽  
Andrew J. Stynes ◽  
David L. Asher
Keyword(s):  
Electrical Stimulation ◽  
Pilot Project ◽  
Behavioral Observation ◽  
Constant Current ◽  
Scala Tympani ◽  
Cochlear Prosthesis ◽  
Biologic Effects ◽  
Stimulation Of ◽  
Human Implantation

Electronic cochlear prostheses are currently being implanted in the profoundly deaf. Little, however, is known about the biologic effects of electrical stimulation of the auditory system. To study some effects of intracochlear electrical stimulation in monkeys, a totally implantable device that produces a constant current similar to that produced by devices now used in human implantation was designed and miniaturized. This paper reports on the characteristics of the device and a pilot project designed to test it in vivo. The feasibility of primate implantation and behavioral observation, as well as histopathologic study, was also determined. The device was implanted in each of two Macacca nemestrina monkeys, which were then observed. One monkey was killed and the implanted cochlea studied with scanning electron microscopy. Evidence of osteogenesis of the scala tympani was found.

scholarly journals Tenderness of the Skin after Chemical Stimulation of Underlying Temporal and Thoracolumbar Fasciae Reveals Somatosensory Crosstalk between Superficial and Deep Tissues

Life ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 370
Author(s):  
Walter Magerl ◽  
Emanuela Thalacker ◽  
Simon Vogel ◽  
Robert Schleip ◽  
Thomas Klein ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Hypertonic Saline ◽  
Detection Threshold ◽  
Constant Current ◽  
Iliotibial Band ◽  
Deep Tissue ◽  
Test Parameter ◽  
Temporal Fascia ◽  
Sufficient Stimulus ◽  
Stimulation Of

Musculoskeletal pain is often associated with pain referred to adjacent areas or skin. So far, no study has analyzed the somatosensory changes of the skin after the stimulation of different underlying fasciae. The current study aimed to investigate heterotopic somatosensory crosstalk between deep tissue (muscle or fascia) and superficial tissue (skin) using two established models of deep tissue pain (namely focal high frequency electrical stimulation (HFS) (100 pulses of constant current electrical stimulation at 10× detection threshold) or the injection of hypertonic saline in stimulus locations as verified using ultrasound). In a methodological pilot experiment in the TLF, different injection volumes of hypertonic saline (50–800 µL) revealed that small injection volumes were most suitable, as they elicited sufficient pain but avoided the complication of the numbing pinprick sensitivity encountered after the injection of a very large volume (800 µL), particularly following muscle injections. The testing of fascia at different body sites revealed that 100 µL of hypertonic saline in the temporal fascia and TLF elicited significant pinprick hyperalgesia in the overlying skin (–26.2% and –23.5% adjusted threshold reduction, p < 0.001 and p < 0.05, respectively), but not the trapezius fascia or iliotibial band. Notably, both estimates of hyperalgesia were significantly correlated (r = 0.61, p < 0.005). Comprehensive somatosensory testing (DFNS standard) revealed that no test parameter was changed significantly following electrical HFS. The experiments demonstrated that fascia stimulation at a sufficient stimulus intensity elicited significant across-tissue facilitation to pinprick stimulation (referred hyperalgesia), a hallmark sign of nociceptive central sensitization.

Electrical stimulation of the auditory nerve: direct current measurement in vivo

1999 ◽  
Vol 46 (4) ◽  
pp. 461-469 ◽  
Author(s):  
C.Q. Huang ◽  
R.K. Shepherd ◽  
P.M. Center ◽  
P.M. Seligman ◽  
B. Tabor
Keyword(s):  
Electrical Stimulation ◽  
Direct Current ◽  
Auditory Nerve ◽  
Current Measurement ◽  
Direct Current Measurement ◽  
Stimulation Of

Hyperinsulinemia of preobese and obese fa/fa rats is partly vagus nerve mediated

1983 ◽  
Vol 244 (4) ◽  
pp. E317-E322 ◽  
Author(s):  
F. Rohner-Jeanrenaud ◽  
A. C. Hochstrasser ◽  
B. Jeanrenaud
Keyword(s):  
Electrical Stimulation ◽  
Insulin Secretion ◽  
B Cells ◽  
Vagus Nerve ◽  
Zucker Rats ◽  
Glucose Load ◽  
Parasympathetic System ◽  
Enhanced Sensitivity ◽  
Stimulation Of

In vivo glucose-induced insulin secretion was greater in preweaned preobese 17-day-old Zucker rats than in the corresponding controls. This hypersecretion of insulin was reversed to normal by acute pretreatment with atropine. A short-lived (30 s) electrical stimulation of the vagus nerve preceding a glucose load potentiated the in vivo glucose-induced insulin release in adult animals (6-9 wk) and more so in obese Zucker (fa/fa) than in lean rats. This suggested the existence of enhanced sensitivity and/or responsiveness of the B cells of obese animals to the parasympathetic system. That the parasympathetic tone was increased in adult obese Zucker (fa/fa) rats was corroborated by the observation that acute vagotomy of these animals resulted in a significant decrease in glucose-induced insulin secretion, whereas no such effect was seen in lean rats. Also, perfused pancreases from adult obese (fa/fa) rats oversecreted insulin during a stimulation by arginine when compared with controls, an oversecretion that was restored toward normal by superimposed infusion of atropine. It is concluded that a) the increased insulin secretion of preobese Zucker fa/fa rats is an early abnormality that is mediated by the vagus nerve, and b) increased secretion of insulin in adult obese fa/fa rats continues to be partly vagus-nerve mediated, although a decreased sympathetic tone and other unknown defects could conceivably play a role as well.

scholarly journals Suppression of Superficial Microglial Activation by Spinal Cord Stimulation Attenuates Neuropathic Pain Following Sciatic Nerve Injury in Rats

2020 ◽  
Vol 21 (7) ◽  
pp. 2390
Author(s):  
Masamichi Shinoda ◽  
Satoshi Fujita ◽  
Shiori Sugawara ◽  
Sayaka Asano ◽  
Ryo Koyama ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Neuropathic Pain ◽  
Electrical Stimulation ◽  
Dorsal Horn ◽  
Nerve Injury ◽  
Spinal Cord Stimulation ◽  
Microglial Activation ◽  
In Vivo Optical Imaging ◽  
Stimulation Of

We evaluated the mechanisms underlying the spinal cord stimulation (SCS)-induced analgesic effect on neuropathic pain following spared nerve injury (SNI). On day 3 after SNI, SCS was performed for 6 h by using electrodes paraspinally placed on the L4-S1 spinal cord. The effects of SCS and intraperitoneal minocycline administration on plantar mechanical sensitivity, microglial activation, and neuronal excitability in the L4 dorsal horn were assessed on day 3 after SNI. The somatosensory cortical responses to electrical stimulation of the hind paw on day 3 following SNI were examined by using in vivo optical imaging with a voltage-sensitive dye. On day 3 after SNI, plantar mechanical hypersensitivity and enhanced microglial activation were suppressed by minocycline or SCS, and L4 dorsal horn nociceptive neuronal hyperexcitability was suppressed by SCS. In vivo optical imaging also revealed that electrical stimulation of the hind paw-activated areas in the somatosensory cortex was decreased by SCS. The present findings suggest that SCS could suppress plantar SNI-induced neuropathic pain via inhibition of microglial activation in the L4 dorsal horn, which is involved in spinal neuronal hyperexcitability. SCS is likely to be a potential alternative and complementary medicine therapy to alleviate neuropathic pain following nerve injury.

scholarly journals Laminar Variation in Threshold for Detection of Electrical Excitation of Striate Cortex by Macaques

2005 ◽  
Vol 94 (5) ◽  
pp. 3443-3450 ◽  
Author(s):  
Edgar A. DeYoe ◽  
Jeffrey D. Lewine ◽  
Robert W. Doty
Keyword(s):  
Electrical Stimulation ◽  
Striate Cortex ◽  
Human Subjects ◽  
Human Case ◽  
Constant Current ◽  
Electrical Excitation ◽  
Detection Thresholds ◽  
Current Pulses ◽  
A Site ◽  
Stimulation Of

Macaques were trained to signal their detection of electrical stimulation applied by a movable microelectrode to perifoveal striate cortex. Trains of ≤100 cathodal, 0.2-ms, constant current pulses were delivered at 50 or 100 Hz. The minimum current that could be reliably detected was measured at successive depths along radial electrode penetrations through the cortex. The lowest detection thresholds were routinely encountered when the stimulation was applied to layer 3, particularly just at the juncture between layers 3 and 4A. On the average, there was a twofold variation in threshold along the penetrations, with the highest intracortical thresholds being in layers 4C and 6. Variations as high as 20-fold were obtained in some individual penetrations, whereas relatively little change was observed in others. The minimum detectable current was 1 μA at a site in layer 3, i.e., 10–100 times lower than that for surface stimulation. Because macaques, as do human subjects, find electrical stimulation of striate cortex to be highly similar at all loci (a phosphene in the human case), it is puzzling as to how such uniformity of effect evolves from the exceedingly intricate circuitry available to the effective stimuli. It is hypothesized that the stimulus captures the most excitable elements, which then suppress other functional moieties, producing only the luminance of the phosphene. Lowest thresholds presumably are encountered when the electrode lies among these excitable elements that can, with higher currents, be stimulated directly from some distance or indirectly by the horizontal bands of myelinated axons, the stria of Baillarger.

scholarly journals A Tissue Engineering Chamber for Continuous Pulsatile Electrical Stimulation of Vascularized Cardiac Tissues In Vivo

2020 ◽  
Vol 2 (4) ◽  
pp. 391-398
Author(s):  
Damián Hernández ◽  
Rodney Millard ◽  
Anne M. Kong ◽  
Owen Burns ◽  
Priyadharshini Sivakumaran ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Electrical Stimulation ◽  
Cardiac Tissues ◽  
Stimulation Of

scholarly journals Characterization of Prejunctional Muscarinic Receptors: Effects on the Release of VIP and Functional Responses and Receptor Expression in the Ovine Submandibular Gland

2009 ◽  
Vol 2009 ◽  
pp. 1-6
Author(s):  
Anders T. Ryberg ◽  
Ondrej Soukup ◽  
Gunnar Tobin
Keyword(s):  
Electrical Stimulation ◽  
Submandibular Gland ◽  
Muscarinic Receptor ◽  
Muscarinic Receptors ◽  
Receptor Expression ◽  
Receptor Subtypes ◽  
Chorda Tympani Nerve ◽  
Functional Responses ◽  
Stimulation Of

In the in vivo experiments on anaesthetized sheep, it was presently examined whether muscarinic receptor antagonists with diverse selectivity affect the release of VIP in response to electrical stimulation of the parasympathetic chorda tympanic nerve differently, and if the changes in the release could be associated to altered secretory and vasodilator responses. The location of the muscarinic receptor subtypes was examined also. In the experiments, blood was collected out of the submandibular venous drainage before and during electrical stimulation of chorda tympani nerve in the absence and presence either of pirenzepine or methoctramine. While metchoctramine increased the output of protein, pirenzepine inhibited flow of saliva and increased protein output, vasodilatation, and VIP output. In morphological examinations, the inhibitory muscarinic M4 receptor occurred interacinarily in the gland. It is concluded that prejunctional muscarinic receptors, most likely of the M4 subtype, exert inhibitory modulation of the parasympathetic release of VIP in the ovine submandibular gland.

Electrical Stimulation of the Guinea Pig Cochlea

1987 ◽  
Vol 96 (4) ◽  
pp. 349-361 ◽  
Author(s):  
Mark J. Maslan ◽  
Josef M. Miller
Keyword(s):  
Electrical Stimulation ◽  
Low Frequency ◽  
Damage Threshold ◽  
Auditory Brainstem ◽  
Cochlear Prosthesis ◽  
Before And After ◽  
Auditory Brainstem Evoked Responses ◽  
Straight Lines ◽  
Histopathologic Findings ◽  
Stimulation Of

As a result of practical considerations, histopathologic findings of the temporal bone in humans with cochlear prosthesis implants have been limited. This project attempts to better define safe parameters of electrical stimulation of the inner ear and compare the safe limits of intracochlear vs. extracochlear stimulation sites. Guinea pigs were implanted with single electrodes either on the promontory or in the scala tympani and were stimulated relative to a remote indifferent for 12 hours distributed over a 4-week period. Electrical auditory brainstem evoked responses (EABRs) were tested before and after each of four 3-hour stimulation sessions. Six weeks after implantation, the animals were killed, and their cochleas were examined under the scanning electron microscope. Intracochlear electrodes exhibited thresholds for damage well below one half of that found for most extracochlear stimulation sites. The function-relating damage threshold (in amperes) to frequency of intracochlear stimulation is represented by two straight lines, with an intercept of 1 kHz. The low-frequency limb exhibited a slope of 3 to 4 dB/octave, whereas the high-frequency limb exhibited a slope of 9 to 10 dB/octave. Extracochlear results were too variable to permit speculation. Changes in EABRs were only variably related to histopathologic findings.

Electrical Cochlear Stimulation in the Deaf Cat: Comparisons Between Psychophysical and Central Auditory Neuronal Thresholds

2000 ◽  
Vol 83 (4) ◽  
pp. 2145-2162 ◽  
Author(s):  
Ralph E. Beitel ◽  
Russell L. Snyder ◽  
Christoph E. Schreiner ◽  
Marcia W. Raggio ◽  
Patricia A. Leake
Keyword(s):  
Electrical Stimulation ◽  
Auditory System ◽  
Pulse Rate ◽  
Auditory Nerve ◽  
Round Window ◽  
Electrode Array ◽  
Scala Tympani ◽  
Behavioral Thresholds ◽  
Current Pulses ◽  
Stimulation Of

Cochlear prostheses for electrical stimulation of the auditory nerve (“electrical hearing”) can provide auditory capacity for profoundly deaf adults and children, including in many cases a restored ability to perceive speech without visual cues. A fundamental challenge in auditory neuroscience is to understand the neural and perceptual mechanisms that make rehabilitation of hearing possible in these deaf humans. We have developed a feline behavioral model that allows us to study behavioral and physiological variables in the same deaf animals. Cats deafened by injection of ototoxic antibiotics were implanted with either a monopolar round window electrode or a multichannel scala tympani electrode array. To evaluate the effects of perceptually significant electrical stimulation of the auditory nerve on the central auditory system, an animal was trained to avoid a mild electrocutaneous shock when biphasic current pulses (0.2 ms/phase) were delivered to its implanted cochlea. Psychophysical detection thresholds and electrical auditory brain stem response (EABR) thresholds were estimated in each cat. At the conclusion of behavioral testing, acute physiological experiments were conducted, and threshold responses were recorded for single neurons and multineuronal clusters in the central nucleus of the inferior colliculus (ICC) and the primary auditory cortex (A1). Behavioral and neurophysiological thresholds were evaluated with reference to cochlear histopathology in the same deaf cats. The results of the present study include: 1) in the cats implanted with a scala tympani electrode array, the lowest ICC and A1 neural thresholds were virtually identical to the behavioral thresholds for intracochlear bipolar stimulation; 2) behavioral thresholds were lower than ICC and A1 neural thresholds in each of the cats implanted with a monopolar round window electrode; 3) EABR thresholds were higher than behavioral thresholds in all of the cats (mean difference = 6.5 dB); and 4) the cumulative number of action potentials for a sample of ICC neurons increased monotonically as a function of the amplitude and the number of stimulating biphasic pulses. This physiological result suggests that the output from the ICC may be integrated spatially across neurons and temporally integrated across pulses when the auditory nerve array is stimulated with a train of biphasic current pulses. Because behavioral thresholds were lower and reaction times were faster at a pulse rate of 30 pps compared with a pulse rate of 2 pps, spatial-temporal integration in the central auditory system was presumably reflected in psychophysical performance.

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