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.

scholarly journals Peripheral vs. central determinants of vibrotactile adaptation

2016 ◽  
Vol 115 (2) ◽  
pp. 685-691 ◽  
Author(s):  
A. Klöcker ◽  
D. Gueorguiev ◽  
J. L. Thonnard ◽  
A. Mouraux
Keyword(s):  
Electrical Stimulation ◽  
Mechanical Vibration ◽  
Detection Threshold ◽  
Nerve Fibers ◽  
Skin Impedance ◽  
Constant Current ◽  
Detection Thresholds ◽  
Mechanical Adaptation ◽  
Before And After ◽  
Stimulation Of

Long-lasting mechanical vibrations applied to the skin induce a reversible decrease in the perception of vibration at the stimulated skin site. This phenomenon of vibrotactile adaptation has been studied extensively, yet there is still no clear consensus on the mechanisms leading to vibrotactile adaptation. In particular, the respective contributions of 1) changes affecting mechanical skin impedance, 2) peripheral processes, and 3) central processes are largely unknown. Here we used direct electrical stimulation of nerve fibers to bypass mechanical transduction processes and thereby explore the possible contribution of central vs. peripheral processes to vibrotactile adaptation. Three experiments were conducted. In the first, adaptation was induced with mechanical vibration of the fingertip (51- or 251-Hz vibration delivered for 8 min, at 40× detection threshold). In the second, we attempted to induce adaptation with transcutaneous electrical stimulation of the median nerve (51- or 251-Hz constant-current pulses delivered for 8 min, at 1.5× detection threshold). Vibrotactile detection thresholds were measured before and after adaptation. Mechanical stimulation induced a clear increase of vibrotactile detection thresholds. In contrast, thresholds were unaffected by electrical stimulation. In the third experiment, we assessed the effect of mechanical adaptation on the detection thresholds to transcutaneous electrical nerve stimuli, measured before and after adaptation. Electrical detection thresholds were unaffected by the mechanical adaptation. Taken together, our results suggest that vibrotactile adaptation is predominantly the consequence of peripheral mechanoreceptor processes and/or changes in biomechanical properties of the skin.

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.

Mechanisms of hemodynamic responses to electrical stimulation of subfornical organ

1986 ◽  
Vol 250 (6) ◽  
pp. R1117-R1122 ◽  
Author(s):  
M. L. Mangiapane ◽  
M. J. Brody
Keyword(s):  
Electrical Stimulation ◽  
Pressor Response ◽  
Subfornical Organ ◽  
Constant Current ◽  
Pulsed Doppler ◽  
Mesenteric Circulation ◽  
Pressor Responses ◽  
Constant Current Stimulation ◽  
Vascular Beds ◽  
Stimulation Of

The rat subfornical organ (SFO) is involved in the pressor response to circulating angiotensin II, and recent evidence indicates that SFO electrical stimulation also produces a pressor response. In the present experiments we examined the hemodynamic, neural, and humoral mechanisms that underlie the pressor response to electrical stimulation of the SFO. Rats were anesthetized with urethan and instrumented with femoral arterial catheters and with pulsed Doppler flow probes on the superior mesenteric and renal arteries and on the abdominal aorta. Constant-current stimulation, delivered to the SFO via tungsten microelectrodes, resulted in stimulus-locked frequency-dependent pressor responses and vasoconstriction in all vascular beds tested. The stimulation-evoked increases in vascular resistance were greatest in the mesenteric circulation and least in the renal. Movement of the electrode away from the SFO produced significantly smaller responses. Ganglionic blockade abolished the responses to electrical stimulation, whereas vasopressin blockade significantly attenuated the responses. The responses of baroreceptor-denervated rats were qualitatively similar to but approximately double in magnitude of those of normal rats. We conclude that electrical stimulation of the SFO elicits widespread regional vasoconstriction that is most pronounced in the mesenteric circulation. The sympathetic nervous system appears responsible for these effects, but there may be facilitation of the responses by vasopressin.

Luteinizing hormone release by cerebral cortex stimulation in rats

1962 ◽  
Vol 203 (6) ◽  
pp. 1109-1112 ◽  
Author(s):  
S. Taleisnik ◽  
L. Caligaris ◽  
J. De Olmos
Keyword(s):  
Ascorbic Acid ◽  
Cerebral Cortex ◽  
Electrical Stimulation ◽  
Luteinizing Hormone ◽  
Hypertonic Saline ◽  
Subcutaneous Injection ◽  
Estradiol Benzoate ◽  
Cortical Stimulation ◽  
Hormone Release ◽  
Stimulation Of

Depletion of ovarian ascorbic acid from highly luteinized ovaries from rats was used as an index of endogenous liberation of luteinizing hormone (LH). When, in such rats, 2 µl of hypertonic saline was injected in the cerebral cortex, significant depletion of ovarian ascorbic acid took place compared with control animals. This stimulus was equally effective in different areas of the cortex that were explored. The mere implantation of the needle gave the same results. Procaine, added at 5% concentration to hypertonic saline, completely blocked cortical stimulation. The same effect was obtained by subcutaneous injection of estradiol benzoate (50 µg) or progesterone (1 mg). In animals with constant estrus, elicited by suprachiasmatic lesion, the response to cortical stimulation was blocked, but not completely. In these animals, however, an intense depletion of ovarian ascorbic acid was obtained by electrical stimulation of the hypothalamus. In animals with constant estrus, induced by injection of testosterone on the 2nd day after birth, the response was also affected. It is concluded that stimuli starting from the cerebral cortex can reach the hypothalamus and induce release of LH.

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.

Convergence of hepatic osmoreceptive inputs on sodium-responsive units within the nucleus of the solitary tract of the rat

1985 ◽  
Vol 54 (2) ◽  
pp. 212-219 ◽  
Author(s):  
M. Kobashi ◽  
A. Adachi
Keyword(s):  
Electrical Stimulation ◽  
Hypertonic Saline ◽  
Topical Application ◽  
Primary Afferents ◽  
Solitary Tract ◽  
Iontophoretic Application ◽  
Discharge Rates ◽  
Hepatic Branch ◽  
Portal Infusion ◽  
Stimulation Of

Single-shock electrical stimulation of the hepatic branch of the vagus induced both facilitation and suppression in units within the nucleus of the solitary tract (NTS). Some units that were facilitated by electrical stimulation also increased their discharge rates during topical iontophoretic application of Na+, as well as portal infusion of hypertonic saline. Other facilitatory units produced opposite responses; their discharge rates decreased during topical iontophoretic application of Na+ and portal infusion of hypertonic saline. Some units that were suppressed by electrical stimulation also responded to the topical application of Na+ and portal infusion of hypertonic saline. The responses to these two different stimuli were positively correlated in some units but not in others. The evidence suggests that the units within the NTS that are responsive to hepatic osmosensitive primary afferents may serve a Na+-responsive function and may be important in integration within the NTS for isosmotic or isovolemic homeostasis.

Fos expression in ferret dorsal vagal complex after peripheral emetic stimuli

1994 ◽  
Vol 266 (4) ◽  
pp. R1118-R1126 ◽  
Author(s):  
F. M. Boissonade ◽  
K. A. Sharkey ◽  
J. S. Davison
Keyword(s):  
Electrical Stimulation ◽  
Hypertonic Saline ◽  
Area Postrema ◽  
Dorsal Vagal Complex ◽  
Solitary Tract ◽  
Communicating Branch ◽  
Nuclear Phosphoprotein ◽  
Fos Expression ◽  
Hypertonic Saline Injection ◽  
Stimulation Of

The aim of this study was to investigate neuronal activation in the dorsal vagal complex of the halothane-anesthetized ferret after peripheral emetic stimuli. Neuronal activity was studied by examining the distribution of the nuclear phosphoprotein Fos using immunohistochemistry. The emetic stimuli used were electrical stimulation of the supradiaphragmatic vagal communicating branch (SVCB) or intraduodenal injection of hypertonic saline. Electrical stimulation of the SVCB induced the densest Fos expression within the medial subnucleus of the nucleus of the solitary tract. After hypertonic saline injection, the greatest density of Fos-positive nuclei was observed within the area postrema and also in the medial subnucleus of the nucleus of the solitary tract. It was concluded that the emetic response to hypertonic saline involves neurons in both the area postrema and the nucleus of the solitary tract, especially the medial subnucleus, and that the medial subnucleus is important in the emetic response to SVCB stimulation.

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