Tactile Detection Threshold Determined with Single Sinusoidal Mechanical Pulses in the Monkey Skin

1986 ◽  
Vol 63 (3) ◽  
pp. 1180-1182
Author(s):  
Antti Pertovaara ◽  
Ilkka Linnankoski
Keyword(s):  
Detection Threshold ◽  
Detection Thresholds ◽  
Stimulus Pulse ◽  
Electrophysiological Studies ◽  
Tactile Detection Thresholds ◽  
Tactile Detection

Tactile detection thresholds for single sinusoidal mechanical pulses increased with decreases in the frequency of the stimulus pulse (from 150 to 20 Hz) in a monkey's skin. The results correspond with those of similar electrophysiological studies.

Fully Tuneable Stochastic Resonance in Cutaneous Receptors

2005 ◽  
Vol 94 (2) ◽  
pp. 928-933 ◽  
Author(s):  
James B. Fallon ◽  
David L. Morgan
Keyword(s):  
Stochastic Resonance ◽  
Biological Systems ◽  
The Other ◽  
Induced Response ◽  
Type I ◽  
Limited Evidence ◽  
Detection Thresholds ◽  
Wide Range ◽  
Tactile Detection Thresholds ◽  
Tactile Detection

Stochastic resonance describes a phenomenon whereby the addition of “noise” to the input of a nonlinear system can improve sensitivity. “Fully tuneable stochastic resonance” is a particular form of the phenomenon that requires the matching of two time scales: one being that of the subthreshold periodic stimulus of the system and the other being the noise-induced response of the system. First proposed in 1981, stochastic resonance has been reported in a wide range of biological systems; however, conclusive experimental evidence for fully tuneable stochastic resonance in biological systems is limited. Evidence of fully tuneable stochastic resonance in the response of slowly adapting type I mechanoreceptors in the toad is presented. The results are extended to include the first evidence supporting fully tuneable stochastic resonance in psychophysical experiments, namely tactile detection thresholds, indicating that the human CNS is capable of accessing the improved information available via fully tuneable stochastic resonance.

scholarly journals Ejaculatory Pain

2007 ◽  
Vol 107 (2) ◽  
pp. 298-304 ◽  
Author(s):  
Eske K. Aasvang ◽  
Bo Møhl ◽  
Henrik Kehlet
Keyword(s):  
Chronic Pain ◽  
Sexual Dysfunction ◽  
Quantitative Sensory Testing ◽  
Groin Hernia ◽  
Pain Treatment ◽  
Detection Threshold ◽  
Control Group ◽  
Sensory Testing ◽  
Detection Thresholds ◽  
Pain Detection

Background Sexual dysfunction due to ejaculatory and genital pain after groin hernia surgery may occur in approximately 2.5% of patients. However, the specific psychosexological and neurophysiologic characteristics have not been described, thereby precluding assessment of pathogenic mechanisms and treatment strategies. Methods Ten patients with severe pain-related sexual dysfunction and ejaculatory pain were assessed in detail by quantitative sensory testing and interviewed by a psychologist specialized in evaluating sexual functional disorders and were compared with a control group of 20 patients with chronic pain after groin hernia repair but without sexual dysfunction, to identify sensory changes associated with ejaculatory pain. Results Quantitative sensory testing showed significantly higher thermal and mechanical detection thresholds and lowered mechanical pain detection thresholds in both groups compared with the nonpainful side. Pressure pain detection threshold and tolerance were significantly lower in the ejaculatory pain group compared with the control group. 'The maximum pain was specifically located at the external inguinal annulus in all ejaculatory pain patients, but not in controls. The psychosexual interview revealed no major psychosexual disturbances and concluded that the pain was of somatic origin. All patients with ejaculatory pain had experienced major negative life changes and deterioration in their overall quality of life and sexual function as a result of the hernia operation. Conclusions Postherniotomy ejaculatory pain and pain-related sexual dysfunction is a specific chronic pain state that may be caused by pathology involving the vas deferens and/or nerve damage. Therapeutic strategies should therefore include neuropathic pain treatment and/or surgical exploration.

scholarly journals Is Peripheral Motion Detection Affected by Myopia?

2021 ◽  
Vol 15 ◽  
Author(s):  
Junhan Wei ◽  
Deying Kong ◽  
Xi Yu ◽  
Lili Wei ◽  
Yue Xiong ◽  
...  
Keyword(s):  
Visual Field ◽  
Spatial Frequency ◽  
Motion Detection ◽  
High Speed ◽  
Detection Threshold ◽  
High Spatial Frequency ◽  
Spherical Equivalent ◽  
Detection Thresholds ◽  
Significant Difference ◽  
Motion Speed

PurposeThe current study was to investigate whether myopia affected peripheral motion detection and whether the potential effect interacted with spatial frequency, motion speed, or eccentricity.MethodsSeventeen young adults aged 22–26 years participated in the study. They were six low to medium myopes [spherical equivalent refractions −1.0 to −5.0 D (diopter)], five high myopes (<-5.5 D) and six emmetropes (+0.5 to −0.5 D). All myopes were corrected by self-prepared, habitual soft contact lenses. A four-alternative forced-choice task in which the subject was to determine the location of the phase-shifting Gabor from the four quadrants (superior, inferior, nasal, and temporal) of the visual field, was employed. The experiment was blocked by eccentricity (20° and 27°), spatial frequency (0.6, 1.2, 2.4, and 4.0 cycles per degree (c/d) for 20° eccentricity, and 0.6, 1.2, 2.0, and 3.2 c/d for 27° eccentricity), as well as the motion speed [2 and 6 degree per second (d/s)].ResultsMixed-model analysis of variances showed no significant difference in the thresholds of peripheral motion detection between three refractive groups at either 20° (F[2,14] = 0.145, p = 0.866) or 27° (F[2,14] = 0.475, p = 0.632). At 20°, lower motion detection thresholds were associated with higher myopia (p < 0.05) mostly for low spatial frequency and high-speed targets in the nasal and superior quadrants, and for high spatial frequency and high-speed targets in the temporal quadrant in myopic viewers. Whereas at 27°, no significant correlation was found between the spherical equivalent and the peripheral motion detection threshold under all conditions (all p > 0.1). Spatial frequency, speed, and quadrant of the visual field all showed significant effect on the peripheral motion detection threshold.ConclusionThere was no significant difference between the three refractive groups in peripheral motion detection. However, lower motion detection thresholds were associated with higher myopia, mostly for low spatial frequency targets, at 20° in myopic viewers.

Electrophysiological and endocrinological evidence that F-series prostaglandins function as priming pheromones in mature male Atlantic salmon (Salmo salar parr

1996 ◽  
Vol 199 (10) ◽  
pp. 2307-2316 ◽  
Author(s):  
A Moore ◽  
C P Waring
Keyword(s):  
Atlantic Salmon ◽  
Olfactory Epithelium ◽  
Plasma Concentrations ◽  
Detection Threshold ◽  
Mature Female ◽  
Mature Male ◽  
Reproductive Physiology ◽  
Electrophysiological Studies ◽  
Female Urine ◽  
Mature Male Parr

Previous work has demonstrated that the urine from mature female salmonids contains a priming pheromone that significantly enhances the reproductive physiology of receiving males. The chemical identity of the pheromone(s) has not yet been identified. The present study investigated the possibility that F-type prostaglandins (PGFs) may have a pheromonal role in Atlantic salmon by measuring the olfactory sensitivity of male salmon to PGFs, the effect of waterborne PGFs on male reproductive physiology and the PGF content of mature female urine. Electrophysiological studies demonstrated that the olfactory epithelium of mature male salmon parr was acutely sensitive to PGF1[alpha] and PGF2[alpha], with detection threshold concentrations of 10(-11) mol l-1. The olfactory epithelium was also sensitive to the PGF metabolite 15-ketoPGF2[alpha] (threshold 10(-8) mol l-1), but did not detect a further metabolite, 13,14-dihydro-15-ketoPGF2[alpha]. Sensitivity to both PGF1[alpha] and PGF2[alpha] increased as the reproductive season progressed. Exposure of mature male parr to waterborne PGF1[alpha] and PGF2[alpha] (10(-8) mol l-1) resulted in significant increases in levels of expressible milt and in the plasma concentrations of 17,20ss-dihydroxy-4-pregnen-3-one, testosterone and 11-ketotestosterone. Urine from ovulated female salmon also contained large quantities (18 ng ml-1) of immunoreactive PGFs, whereas urine from mature males and non-ovulated mature females contained significantly smaller amounts (<1 ng ml-1). The results support the theory that PGFs function as priming pheromones in Atlantic salmon and are released in the urine of ovulated female salmon. The involvement of these pheromones in synchronising male-female salmon spawning is discussed.

scholarly journals A Robot Has a Mind of Its Own Because We Intuitively Share It

2020 ◽  
Vol 10 (18) ◽  
pp. 6531
Author(s):  
Mizuho Sumitani ◽  
Michihiro Osumi ◽  
Hiroaki Abe ◽  
Kenji Azuma ◽  
Rikuhei Tsuchida ◽  
...  
Keyword(s):  
Pain Intensity ◽  
Facial Expressions ◽  
Detection Threshold ◽  
Two Dimensions ◽  
Virtual Agent ◽  
Cold Pain ◽  
Detection Thresholds ◽  
Pain Detection ◽  
Pain Experiences ◽  
The Mind

People perceive the mind in two dimensions: intellectual and affective. Advances in artificial intelligence enable people to perceive the intellectual mind of a robot through their semantic interactions. Conversely, it has been still controversial whether a robot has an affective mind of its own without any intellectual actions or semantic interactions. We investigated pain experiences when observing three different facial expressions of a virtual agent modeling affective minds (i.e., painful, unhappy, and neutral). The cold pain detection threshold of 19 healthy subjects was measured as they watched a black screen, then changes in their cold pain detection thresholds were evaluated as they watched the facial expressions. Subjects were asked to rate the pain intensity from the respective facial expressions. Changes of cold pain detection thresholds were compared and adjusted by the respective pain intensities. Only when watching the painful expression of a virtual agent did, the cold pain detection threshold increase significantly. By directly evaluating intuitive pain responses when observing facial expressions of a virtual agent, we found that we ‘share’ empathic neural responses, which can be intuitively emerge, according to observed pain intensity with a robot (a virtual agent).

Performance of Fiber-Optic Raman Probes for Analysis of Gas Mixtures in Enclosures

2002 ◽  
Vol 56 (1) ◽  
pp. 83-90 ◽  
Author(s):  
John M. Berg ◽  
Karen C. Rau ◽  
D. Kirk Veirs ◽  
Laura A. Worl ◽  
James T. McFarlan ◽  
...  
Keyword(s):  
Optical Fibers ◽  
Fiber Optic ◽  
Detection Threshold ◽  
Gas Mixtures ◽  
Cylindrical Sample ◽  
Colored Glass ◽  
Signal Acquisition ◽  
Fiber Optic Probe ◽  
Detection Thresholds ◽  
Factors Affecting

The feasibility of using fiber-optic Raman probes to identify and quantify gases in enclosures is investigated by measuring and comparing detection thresholds using several probe and enclosure designs. Unfiltered, non-imaging, fiber-optic probes are shown to achieve lower detection thresholds than a filtered, imaging, fiberoptic probe, provided that light scattering within the sample enclosure is minimized and provided that a window is not used between the probe and the analyte gas. Achievable thresholds for hydrogen, oxygen, nitrogen, carbon monoxide, and methane in gas mixtures are demonstrated to be below 1 kPa with ten seconds signal acquisition and 0.1 kPa with twenty minutes signal acquisition with the use of 0.4 W of 532-nm excitation. Ambient carbon dioxide in air (.03 kPa) is shown to be detectable in a twenty minute acquisition, and ambient water vapor is well above the detection threshold. Background signals generated within the optical fibers remain the principal factors limiting detection thresholds. Factors affecting the magnitudes of these signals reaching the detector are investigated and discussed. A flat piece of light-absorbing colored glass tilted to direct reflected light away from the fiber-optic probe performs well as a beam stop to reduce background signal in a simple, cylindrical sample enclosure.

Temporal Integration and the Masking Effect of Spatiotemporal Noise

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 216-216 ◽  
Author(s):  
H T Kukkonen ◽  
J Rovamo
Keyword(s):  
Spectral Density ◽  
Exposure Duration ◽  
Temporal Integration ◽  
Detection Threshold ◽  
Critical Duration ◽  
Masking Effect ◽  
Integration Time ◽  
Detection Thresholds ◽  
Spatial Noise ◽  
Spatiotemporal Noise

In computer-generated spatiotemporal noise every stimulus frame contains a new static noise sample. The spectral density of white spatiotemporal noise is calculated by multiplying the squared rms contrast of noise by the product of the noise check area and the exposure duration of each noise check. When the exposure duration of each noise check is gradually increased, the spectral density of spatiotemporal noise increases, reaching its maximum when noise becomes static. In static spatial noise both stimulus and noise checks have the same duration. The signal-to-noise ratio is known to be constant at detection threshold. Detection thresholds should thus increase in proportion to the spectral density of spatiotemporal noise, which increases with the duration of the noise checks. We measured detection thresholds for stationary cosine gratings embedded in spatiotemporal noise. The exposure duration of the noise checks was increased from one frame duration to the total exposure duration of the stimulus grating. Noise was thus gradually transformed from spatiotemporal to static spatial noise. The contrast energy threshold increased in proportion to the spectral density of spatiotemporal noise up to a noise check duration found to be equal to the integration time for the stimulus grating without noise. After this, energy thresholds remained constant in spite of the increase in the spectral density of spatiotemporal noise. This suggests that the masking effect of spatiotemporal noise increases with the duration of noise checks up to the critical duration marking the saturation of the temporal integration of the signal.

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