• The Korean Journal of Physiology and Pharmacology
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• v.1 no.6
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• pp.625-637
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• 1997

Calcium ions are implicated in a variety of physiological functions, including enzyme activity, membrane excitability, neurotransmitter release, and synaptic transmission, etc. Calcium antagonists have been known to be effective for the treatment of exertional angina and essential hypertension. Selective and nonselective voltage-dependent calcium channel blockers also have inhibitory action on the acute and tonic pain behaviors resulting from thermal stimulation, subcutaneous formalin injection and nerve injury. This study was undertaken to investigate the effects of iontophoretically applied $Ca^{++}$ and its antagonists on the responses of WDR (wide dynamic range) cells to sensory inputs. The responses of WDR cells to graded electrical stimulation of the afferent nerve and also to thermal stimulation of the receptive field were recorded before and after iontophoretical application of $Ca^{++}$, EGTA, $Mn^{++}$, verapamil, ${\omega}-conotoxin$ GVIA, ${\omega}-conotoxin$ MVIIC and ${\omega}-agatoxin$ IVA. Also studied were the effects of a few calcium antagonists on the C-fiber responses of WDR cells sensitized by subcutaneous injection of mustard oil (10%). Calcium ions and calcium channel antagonists ($Mn^{++}$, verapamil, ${\omega}-conotoxin$ GVIA & ${\omega}-agatoxin$ IVA) current-dependently suppressed the C-fiber responses of WDR cells without any significant effects on the A-fiber responses. But ${\omega}-conotoxin$ MVIIC did not have any inhibitory actions on the responses of WDR cell to A-fiber, C-fiber and thermal stimulation. Iontophoretically applied EGTA augmented the WDR cell responses to C-fiber and thermal stimulations while spinal application of EGTA for about $20{\sim}30\;min$ strongly inhibited the C-fiber responses. The augmenting and the inhibitory actions of EGTA were blocked by calcium ions. The WDR cell responses to thermal stimulation of the receptive field were reduced by iontophoretical application of $Ca^{++}$, verapamil, ${\omega}-agatoxin$ IVA, and ${\omega}-conotoxin$ GVIA but not by ${\omega}-conotoxin$ MVIIC. The responses of WDR cells to C-fiber stimulation were augmented after subcutaneous injection of mustard oil (10%, 0.15 ml) into the receptive field and these sensitized C-fiber responses were strongly suppressed by iontophoretically applied $Ca^{++}$, verapamil, ${\omega}-conotoxin$ GVIA and ${\omega}-agatoxin$ IVA. These experimental findings suggest that in the rat spinal cord, L-, N-, and P-type, but not Q-type, voltage-sensitive calcium channels are implicated in the calcium antagonist-induced inhibition of the normal and the sensitized responses of WDR cells to C-fiber and thermal stimulation, and that the suppressive effect of calcium and augmenting action of EGTA on WDR cell responses are due to changes in excitability of the cell.

• The Journal of the Korea Contents Association
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• v.10 no.2
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• pp.286-294
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• 2010

This study was performed to identify the cerebral network associated with sensation through the tickling stimulation, which is distinctive from the rest of other networks processing normal stimulation and to investigate the difference of laughing mechanism which is closely related to tickling using functional MRI(fMRI). A 16 healthy volunteers (mean age: 28.9) on a 3.0T MR scanner during two sensation conditions. Counterbalanced stimulus were presented across the participants, and the stimulation was used block design. Acquired data was analyzed by the statistical parametric mapping (SPM 99). Subject and group analysis was performed. Individual analysis showed the activation of somatic sensation area in both tasks and the tickling sensation test showed more activated area in the Wernicke's area(BA40) compared to the normal sensation. The group analysis result shows that under normal stimulations, both sides of somatosensory cortices(BA 1,2 and 3) were activated and under tickling stimulation, not only the cortices but also those huge activation on thalamus, cingulate gyrus and insular lobe were detected. When the tickling was stopped, significant activations were shown in right cingulate gyrus, left MFG area and left insular lobe. A cerebral area responsible for recognizing tickling sensation was examined and the primitive stimulation such as tickling is much closely related to laugh, which is an important factor for various social activities.

• Journal of Acupuncture Research
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• v.20 no.4
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• pp.145-156
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• 2003

Objective : This study is to investigate the effect of electro-acupuncture ST36 on altered transmission of afferent somatosensory information caused by amyloid-${\beta}$(A-${\beta}$) that caused Alzheimer's disease. Methods : The effects of topical application of A-${\beta}$, A-${\beta}$ with ST36, aggregated A-${\beta}$(aA-${\beta}$), aA-${\beta}$ with ST36 and ST36 on the afferent sensory transmission to the neurons in the primary somatosensory(SI) cortex was observed in anesthetized rats. Quantitative determination of the effects of A-${\beta}$, A-${\beta}$ with ST36, aA-${\beta}$, aA-${\beta}$ with ST36 and ST36 was made by generating poststimulus time histogram of evoked response of individual cortical neuron by electrical stimulation of the receptive located in peripheral area(forepaw) Results : The results obtained in present study were summerized as follow : 1. Application of physiological concentrative 0.5 nM A-${\beta}$ caused afferent sensory transmission of SI cortex facilitated. 0.5 nM A-${\beta}$ with ST36 exerted much stronger effects than 0.5 nM A-${\beta}$ alone. 2. Application of $10{\mu}M$ A-${\beta}$ caused afferent sensory transmission of SI cortex unchangeable. But $10{\mu}M$ A-${\beta}$ with ST36 is facilitated at 30 min of post-drug period 3. Application of $10{\mu}M$ aA-${\beta}$ caused afferent sensory transmission of SI cortex diminished. $10{\mu}M$ aA-${\beta}$ with ST36 is diminished after 15min of post-drug period but is facilitated after 75min.

• Physical Therapy Korea
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• v.22 no.3
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• pp.41-49
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• 2015

This study aimed to evaluate the surface area and velocity of center of pressure (COP) during one leg standing by stimulating the sensory system in normal adults. Thirty subjects were enrolled in this study. Subjects were asked to stand on one leg during testing conditions. Testing conditions included 6 different sensory stimulations as follows: eyes opened, eyes closed, eyes opened with vibrator, eyes opened with head-mounted display (HMD), eyes opened with vibrator and HMD, and eyes closed with vibrator. During each testing condition, the surface area and velocity of center of pressure were measured. There were significant differences in the mean surface area and the mean velocity of COP between the "eyes opened" condition and the other five testing conditions (p<.05). However, in the comparison between the "eyes closed" and "eyes opened with HMD" conditions, there were no significant differences in the tested parameters. This study shows that closing eyes or keeping eyes opened while using HMD to experience virtual reality has the same effect on one leg standing balance. This finding should be considered in the evaluation or intervention of balance, especially one leg standing balance and balance while standing with a small base of support.

• Korean Journal of Clinical Laboratory Science
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• v.37 no.3
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• pp.212-215
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• 2005

Carpal tunnel syndrome (CTS) is the most common entrapment neuropathy in clinical practice, with a 0.1% life time risk in the general population. Conventional neurophysiological studies have been useful in the diagnosis of this condition, as have a number of more specialized procedures. Therefore, we evaluated the diagnostic sensitivities of several parameters in nerve conduction technique for CTS patients. We analyzed 100 patients (159 hands) who were diagnosed with CTS clinically and electrophysiolosically. Median motor and sensory nerve conduction velocities (MCV and SCV) with wrist, palm, and finger stimulation were performed in traditional methods. Sensitivities of each test were calculated and compared to normal control data. The sensitivities of existing nerve conduction method were noted in terminal latency on median nerve, 2nd finger-wrist segment, 3rd finger-wrist segment, palm-wrist segment and distoproximal ratio, as 72.96%, 92.45%, 94.34%, 94.97%, and 97.48%, respectively. In the early course of CTS, sensory nerve conductions in the median nerve are more valuable than motor nerve conduction. Sensory nerve conductions are usually affected before motor nerve conductions in CTS. In this study, we detected that slowing of median SCV was the most frequent in the distoproximal ratio.

• The Korean Journal of Pain
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• v.36 no.2
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• pp.173-183
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• 2023

Background: Understanding the stability of quantitative sensory tests (QSTs) over time is important to aid clinicians in selecting a battery of tests for assessing and monitoring patients. This study evaluated the short- and long-term reliability of selected QSTs. Methods: Twenty healthy women participated in three experimental sessions: Baseline, 2 weeks, and 6 months. Measurements included pressure pain thresholds (PPT) in the neck, upper back, and leg; Pressure-cuff pain tolerance around the upper-arm; conditioned pain modulation during a pressure-cuff stimulus; and referred pain following a suprathreshold pressure stimulation. Intraclass correlation coefficients (ICC) and minimum detectable change (MDC) were calculated. Results: Reliability for PPT was excellent for all sites at 2 weeks (ICC, 0.96-0.99; MDC, 22-55 kPa) and from good to excellent at 6 months (ICC, 0.88-0.95; MDC, 47-91 kPa). ICC for pressure-cuff pain tolerance indicated excellent reliability at both times (0.91-0.97). For conditioned pain modulation, reliability was moderate for all sites at 2 weeks (ICC, 0.57-0.74; MDC, 24%-35%), while it was moderate at the neck (ICC, 0.54; MDC, 27%) and poor at the upper back and leg at 6 months. ICC for referred pain areas was excellent at 2 weeks (0.90) and good at 6 months (0.86). Conclusions: PPT, pressure pain tolerance, and pressure-induced referred pain should be considered reliable procedures to assess the pain-sensory profile over time. In contrast, conditioned pain modulation was shown to be unstable. Future studies prospectively analyzing the pain-sensory profile will be able to better calculate appropriate sample sizes.

• Journal of the Korean Academy of Clinical Electrophysiology
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• v.7 no.1
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• pp.23-27
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• 2009

Purpose : The purpose of this study was to examine the effects of different medium frequency currents on afferent fibers. Methods : Thirty healthy volunteers who had no known history of neurological disorders were equally assigned to one of three groups; 2500Hz, 4000Hz, and control and each group was applied to the left wrist in palmer cutaneous branch of radial nerve by different medium frequency currents for 15 min. We measured the changes of thresholds for tactile, two-point discrimination, and thresholds for pain. Results : The results showed that the medium frequency currents stimulation increased thresholds for tactile, two-point discrimination, and thresholds for pain. However, there is no statistically significant difference between group 2500Hz and group 4000Hz. Conclusion : This may explain thresholds for tactile, two-point discrimination, and thresholds for pain plain medium frequency currents stimulation inhibits the excitability of afferent fibers, but the effect of the frequency difference within medium frequency currents is not demonstrated.

• Journal of Korean Neurosurgical Society
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• v.38 no.5
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• pp.338-343
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• 2005

Objective : The sacroiliac joint complex is often related with functionally incapacitating pain in old aged people. The purpose of this study is to delineate the investigation strategies and to determine the long-term effect of radiofrequency [RF] neurotomies for pain arising from sacroiliac Joint dysfunction[SIJD]. Methods : Sixteen patients were diagnosed as having chronic pain from SIJD by comparative controlled blocks on L5 dorsal rami, sacroiliac Joints and deep interosseous ligaments. After confirming the positive response [more than 50% of pain relief], sensory stimulation was applied to detect the 'pathological' branches. Subsequently, RF neurotomies were performed on the selected nerve branches. Surgical outcome was graded as successful, moderate improvement, and failure after a 6month follow-up period. Results : Stimulation intensity was 0.45V to elicit pain response in the L5 dorsal rami and lateral sacral branches. The number of RF-lesioned nerve branches was 6per patient. The average number of lesions for each branch was 1.3. Most commonly selected branches were L5 dorsal ramus [88%] and S2-upper division [88%]. Ten patients [63%] reported a successful outcome according to the outcome criteria after 6months of follow-up, and five patients [31%] reported complete relief [100%]. Five patients [31%] showed moderate improvements. One patient reported failure. Conclusion : RF neurotomy of lateral sacral branches is an excellent treatment modality for the pain due to SIJD, provided that comparative controlled block shows a positive response.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.145-150
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• 2005

This paper presents an Electrotactile Display System (ETCS). One of the most important human sensory systems for human computer interaction is the sense of touch, which can be displayed to human through tactile output devices. To realize the sense of touch, electrotactile display produces controlled, localized touch sensation on the skin by passing small electric current. In electrotactile stimulation, the mechanoreceptors in the skin may be stimulated individually in order to display the sense of vibration, touch, itch, tingle, pressure etc. on the finger, palm, arm or any suitable location of the body by using appropriate electrodes and waveforms. We developed an ETCS and investigated effectiveness of the proposed system in terms of the perception of roughness of a surface by stimulating the palmar side of hand with different waveforms and the perception of direction and location information through forearm. Positive and negative pulse trains were tested with different current intensities and electrode switching times on the forearm or finger of the user with an electrode-embedded armband in order to investigate how subjects recognize displayed patterns and directions of stimulation.

• Proceedings of the Korean Society for Cognitive Science Conference
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• 2010.05a
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• pp.48-54
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• 2010

INTRODUCTION Interaction between temporal events at the millisecond level is important for visual and tactile interaction. OBJECT The aim of the present study is to identify any neural signature, as reflected in event-related potentials (ERP), for the integrative processes when the two sensory modalities are stimulated in synchrony as opposed to when they are stimulated separately. METHOD The basic strategy was to compare ERP signals obtained with simultaneous visual and tactile stimulation with a linear summation of ERP patterns obtained with each modality stimulated separately. Condition were presented, paired with various stimulus-onset-asynchronies (SOA) ranging from - 300 ms (tactile-first) to 300 ms (visual-first), and in trials where only one modality was stimulated alone. RESULT A positive deviation was located in observed ERP at C4 electrode (contralateral to the stimulated hand) at 200-400 ms, in comparison to the predicted ERP. The deviation was present at all SOAs other than -300ms (tactile-first) and 300 ms (visual-first). There was also a positive deviation at occipital leads at the 50-ms SOA (visual-first) trials. DISCUSSION It suggested that neural signatures of cross-modal integration occur within a limited time-window. The deviations were specifically localized at the contralateral somatosensory and visual cortices, indicating that the integration happens at or before the level of the primary cortices.