• 제목/요약/키워드: Threshold stimulus

검색결과 69건 처리시간 0.025초

Normal data on axonal excitability in Koreans

  • Lee, Ju Young;Yu, Jin Hyeok;Pyun, So Young;Ryu, Sanghyo;Bae, Jong Seok
    • Annals of Clinical Neurophysiology
    • /
    • 제19권1호
    • /
    • pp.34-39
    • /
    • 2017
  • Background: Automated nerve excitability testing is used to assess various peripheral neuropathies and motor neuron diseases. Comparing these excitability parameters with normal data provides information regarding the axonal excitability properties and ion biophysics in diseased axons. This study measured and compared normal values of axonal excitability parameters in both the distal motor and sensory axons of normal Koreans. Methods: The axonal excitability properties of 50 distal median motor axons and 30 distal median sensory axons were measured. An automated nerve excitability test was performed using the QTRACW threshold-tracking software (Institute of Neurology, University College London, London, UK) with the TRONDF multiple excitability recording protocol. Each parameter of stimulus-response curves, threshold electrotonus, current-voltage relationship, and recovery cycle was measured and calculated. Results: Our Korean normal data on axonal excitability showed ranges of values and characteristics similar to previous reports from other countries. We also reaffirmed that there exist characteristic differences in excitability properties between motor and sensory axons: compared to motor axons, sensory axons showed an increased strength-duration time constant, more prominent changes in threshold to hyperpolarizing threshold electrotonus (TE) and less prominent changes in threshold to depolarizing TE, and more prominent refractoriness and less prominent subexcitability and superexcitability. Conclusions: We report normal data on axonal excitability in Koreans. These data can be used to compare various pathological conditions in peripheral nerve axons such as peripheral neuropathies and motor neuron disease.

Allyl Isothiocyanate 유발 피부염에 의한 척수후각세포의 활동성 변동 (Modification in the Responsiveness of Dorsal Horn Cells during Allyl Isothiocyanate-Induced Inflammation in the Cat)

  • 윤영복;김진혁;신홍기;김기순
    • The Korean Journal of Physiology
    • /
    • 제24권2호
    • /
    • pp.305-317
    • /
    • 1990
  • The present study was performed to investigate modification in the electrophysiological characteristics of cat dorsal horn cells during neurogenic inflammation induced by mustard oil. The results obtained were summarized as follows: 1) Following subcutaneous injection of mustard oil the majority of wide dynamic range (WDR) cells (10/15 units) showed enhanced responses (80%) to brush, while the responses to all types of mechanical stiumli were enhanced in 3/15 units. One cell was further activated by pinch and the another was not affected at all after induction of inflammation. 2) The sensitization of WDR cell was resulted from subcutaneous injection of mustard oil either inside or outside of the receptive field (RF), whereas the spontaneous activity increased only after mustard oil was injected inside of the RF. 3) In the animal with inflammation the responses of high threshold (HT) cell to noxious stimulus were not altered, while HT cell responded to such mechanical stimulus as pressure which was usually ineffective in normal animals. 4) After induction of inflammation, low threshold (LT) cell appeared to be converted to WDR cell, showing responses not only to brush but also to pressure and pinch. 5) The mustard oil-induced inflammation enhanced responses of WDR and HT cells to the thermal stimuli and also resulted in a pronounced after-discharge in WDR cells. 6) After subcutaneous injection of lidocaine, the increased background activity of WDR cells due to inflammation was almost completely abolished. 7) A subcutaneous injection of mustard oil inside of the RF invariably desensitized the dorsal horn cells which receive sensory inputs from the inflamed RF. From the results of Present study it was revealed that a neurogenic inflammation induced by mustard oil resulted in an enhancement of responses of cat dorsal horn cells to mechanical and thermal stimuli.

  • PDF

S-JND 모델을 사용한 주관적인 율 제어 알고리즘 기반의 HEVC 부호화 방법 (A Perceptual Rate Control Algorithm with S-JND Model for HEVC Encoder)

  • 김재련;안용조;임웅;심동규
    • 방송공학회논문지
    • /
    • 제21권6호
    • /
    • pp.929-943
    • /
    • 2016
  • 본 논문에서는 인지 화질을 고려하기 위해 S-JND 모델 기반의 율 제어 알고리즘을 제안한다. 제안하는 율 제어 알고리즘은 인간이 가지는 시각 시스템의 특징을 반영하기 위하여 시각적 민감도와 시각적 관심도를 동시에 반영할 수 있도록 제작된 S-JND (Saliency-Just Noticeable Difference) 모델을 사용한다. 율 제어 알고리즘을 통해 비트를 분배하는 과정에서 픽쳐 내에 존재하는 각 CTU (Coding Tree Unit)가 가지는 S-JND threshold를 구한다. 각 CTU의 threshold는 적응적으로 적절한 비트를 분배하는데 사용되고, 따라서 제안하는 비트 분배 모델은 인지 화질을 향상 시킬 수 있다. 제안하는 방법의 성능 검증을 위해서 제안하는 방법을 HM 16.9에 구현하였으며, CTC (Common Test Condition) RA (Random Access), Low-delay B와 Low-delay P의 경우에 Class B와 Class C 영상들에 대해 실험 하였다. 실험 결과, 제안하는 방법은 기존 율 제어 알고리즘 대비 평균 2.3%의 비트율이 감소했고 BD-PSNR은 약 0.07dB 향상이 있었으며 비트 정확도 또한 0.06% 정도 증가하였다. DSCQS (Double Stimulus Continuous Quality Scale) 방법으로 측정한 결과, 제안하는 방법은 기존 방법 대비 0.03 MOS (Mean Opinion Score) 향상을 보였다.

성인의 Current Perception Threshold 예비조사 (The Preliminary Study for Normative Current Perception Threshold values in the Korean Adults)

  • 박대규;천성홍;전재수;김용익;황경호;박욱
    • The Korean Journal of Pain
    • /
    • 제10권1호
    • /
    • pp.5-10
    • /
    • 1997
  • Background : The Current Perception Threshold (CPT) provides an objective, quantitative gauge of sensory nerve integrity which is obtainable from any cutaneous site. CPT measurement can confirm and quantify or rule out dysfunction of nerve through comparison with established normative values ($Neuval^{TM}$ CPT database). The aim of this study is to compare collected data from Korean adults with $Neuval^{TM}$ CPT database. Method : Normative data from 5 standard test site in face, hand, toe were obtained from 50 healthy adults. Three frequencies(5, 250, 2000 Hz) were stimulated with $Neuromoter^{(R)}$ CPT device. Results : The results of our data were statistically significantly different than Neuval data except in face, but within normal range. Sensory Threshold increased as the frequency of the stimulus changed from 5 Hz to 250 Hz to 2000 Hz., and from face to hand to toe. Conclusion : CPT testing is a valuable neurologic testing modality that is noninvasive and highly reliable for diagnosis and evaluation of sensory nerves where neuropathy is suspected.

  • PDF

Fabrication and Evaluation of Tactile Stimulator Array Using Stacked PZT

  • Yoon, Myoung-Jong;Kwon, Tae-Kyu;Yu, Kee-Ho;Kim, Nam-Gyun
    • 제어로봇시스템학회:학술대회논문집
    • /
    • 제어로봇시스템학회 2004년도 ICCAS
    • /
    • pp.171-175
    • /
    • 2004
  • A tactile stimulator array using stacked PZT is fabricated and evaluated in this paper. The purpose of this research is the development of a tactile stimulator to represent the obstacle information for the visually disabled. As a first step of this research, we investigate the physiological characteristics of tactile stimuli and design a tactile stimulator based on the investigated results. Also we evaluated a fabricated tactile stimulator. The prototype of tactile stimulator which has 2x2 tactor elements with 3mm spacing is fabricated using stacked PZT actuator. In order to evaluate the characteristics of this tactile stimulator, physiological experiments are carried out. In the experiment, the threshold of tactile stimulus intensity within a frequency range of 5-500Hz and at various stimulus amplitudes are investigated. According to the obtained experimental result, the input signal of tactile stimulator for the transfer of obstacle information is determined. Also physiological experiments of multi-stimuli recognition such as shift and rotation are carried out.

  • PDF

신경모델링을 이용한 인공와우 전기자극 패턴 연구 (Study on Electric Stimulus Pattern in Cochlear Implant Using a Computer Model)

  • 양혜진;우지환
    • 전자공학회논문지
    • /
    • 제49권12호
    • /
    • pp.249-255
    • /
    • 2012
  • 청각 신경의 정상적 기능 회복을 위해 사용하는 인공와우는 인체 조직에 손상을 주는 단상파 방식의 펄스 대신 전하량 균형을 이루는 이상파 방식의 전기적 펄스를 사용한다. 본 논문에서는, Hodgkin-Huxley 신경 모델에 기반하여 다양한 전기적 펄스 방식의 자극이 신경 반응에 미치는 영향에 대하여 연구하였다. 전기적 펄스의 펄스 폭, 펄스간 간격 등을 변화시키면서, 청각신경의 역치, 반응 범위, 반응 시간 등을 측정하였다. 이러한 결과는 인공와우 시스템의 효과적인 자극 방식을 디자인 하는데, 활용 될 수 있으리라 기대된다.

뇌졸중 환자의 경직 및 관절가동범위, 균형에 간섭전류 치료가 미치는 효과 (The Effects of Interferential Current therapy on Spasticity, Range of Motion, and Balance Ability in stroke Patient)

  • 김보용;최원호
    • The Journal of Korean Physical Therapy
    • /
    • 제25권4호
    • /
    • pp.187-194
    • /
    • 2013
  • Purpose: The aim of this study was to investigate the effects of interferential current therapy (ICT) on spasticity, ROM, and the balance function in patients with stroke. Methods: 30 inpatients with stroke were randomly divided into 2 groups: the ICT group (n=15) and the placebo-ICT group (n=15). Two groups have got the traditional rehabilitation for 30 minutes before applying either ICT or placebo-ICT stimulation. The stimulus of ICT has been applied to gastrocnemius at the level of 100 Hz, two times of sensation threshold, while the placebo-ICT group has put on the electrode without electrical stimulus. To assess spasticity in ankle, the modified Ashworth scale (MAS) was used, and goniometer was applied to measure the passive range of motion (PROM). Also, the Berg Balance Scale (BBS), the Timed-up and go (TUG), and the Functional Reach Test (FRT) were carried out to examine the balance ability. Results: The ICT group showed a significant reduction of spasticity and significantly increased PROM than the placebo-ICT group (p<0.05). The placebo-ICT group did not show significant changes in the BBS, the TUG, and the FRT, while the ICT group significantly improved the BBS, the TUG, and the FRT (p<0.05). Conclusion: Our results demonstrated that ICT applied to gastrocnemius effectively decreased spasticity and improved range of motion and balance function in patients with stroke.

전기 치수 검사 시 역치 자극 이후 과용(過用) 자극 시간의 측정 (MEASUREMENT OF THE EXCESSIVE STIMULUS TIME AFTER THE SENSORY THRESHOLD LEVEL DURING ELECTRIC PULP TESTING)

  • 남기창;안선희;김수찬;김덕원;이승종
    • Restorative Dentistry and Endodontics
    • /
    • 제29권3호
    • /
    • pp.226-232
    • /
    • 2004
  • Use of electric pulp testing elicits painful response in vital teeth. In this study, we examined the excessive time from pain feeling to stimulation disconnection in clinical situation. D626D (Parkell Inc., USA.) scan type electric pulp tester was used in total of 23 young healthy individuals. Each of the right central incisors and first premolars were used as testing teeth. Stimulation disconnection was achieved by EMG in anterior belly of digastric muscle, finger span, and voice and the excessive stimulation time over the sensory thresh-old was recorded. As a result, we found that the short responses before the stimulation disconnection appeared following order:EMG, finger span, and voice. The EMG disconnection is suggested to be used to reduce the excessive stimulus time in electric pulp testing.

Conceptualizing 5G's of Green Marketing for Retail Consumers and Validating the Measurement Model Through a Pilot Study

  • ANSARI, Hafiz Waqas Ahmed;FAUZI, Waida Irani Mohd;SALIMON, Maruf Gbadebo
    • 유통과학연구
    • /
    • 제20권4호
    • /
    • pp.33-50
    • /
    • 2022
  • Purpose: This pilot study aims to conceptualize a new green marketing mix for retail consumers based on Stimulus-Organism-Response (SOR) model. Moreover, it also aims to conceptualize a testable research model of new green marketing mix with consumers' green purchasing behavior, and to validate the measurement model with traditional as well as modern suggested validating techniques. Research design, data and methodology: A pilot test data from 75 respondents of retail buyers of energy-efficient electric appliances in Pakistan were tested for the confirmatory factor analysis (CFA) by examining a measurement model of the construct through different validation techniques (like Composite Reliability, McDonald's Omega (ω), rho (ρA), HTMT, etc.) as heretofore these scales were not validated through these modern methods. Results: The results revealed that the instrument has a certain degree of reliability and validity through different validating techniques. All the measurement items reach the suggested threshold values. Conclusions: Therefore, this study conceptualized an integrated framework of all the three stakeholders of the environment (government, companies, and public or consumers) to achieve environmental sustainability. Hence, future studies can extend these findings and conduct a full-scale study to establish an empirical relationship between the 5G's of green marketing for retailing businesses and consumers' green purchase behavior.

주정의존에서 성기능장애와 말초신경염의 연관성 (Association of Sexual Disorders with Peripheral Neuropathy in Alcohol Dependence)

  • 전진숙;한호성;김기찬;정호중
    • 생물정신의학
    • /
    • 제4권1호
    • /
    • pp.108-115
    • /
    • 1997
  • The alcoholic neuropathies developed in approximately 34% of chronic alcoholics and the sexual dysfunction had been experienced in 8-54% of male alcoholics(Schiavi 1990). The aims of this study were to identify the prevalence of subclinical polyneuropathies and sexual disorders in alcohol dependence, and to evaluate the association between them. The nerve conduction velocity(NCV), electromyography(EMG), and pudendal somatosensory evoked potentials(SEPs) were tested for the male alcoholics(N=34) and controls(N=17 for NCV & EMG, N=25 for pudendal SEPs). The pudendal SEPs were measured by the following procedures, in which we stimulated the dorsal nerve of penis attached by the ring electrode(stimulus intensity, three times of threshold : stimulus rate, 1-4.7Hz : stimulus duration, 0.1 or 0.2msec), and recorded at the scalp(active electrode, 2cm behind Cz : reference electrode, Fz). The NCV and EMG detected signs of peripheral neuropathies in 79.4% of alcoholics. Among the alcoholics, 64.7% were abnormal on the pudendal SEPs. Among the alcoholics who revealed abnormality on EMG and NCV, 81.4% were abnormal on the pudendal SEPs, in which 51.9% were not responded. The P1 latencies of pudendal SEPs on neuropathic alcoholics were significantly delayed(p<0.05) than non-neuropathic alcoholics. There was a relative correlation between peripheral neuropathies and sexual disorders in the alcoholics. The prevalence of subclinical neuropathies and sexual disorders seemed to be much higher in alcohol dependence than expectation, and these two problems were relatively correlated, and our results suggested that the peripheral polyneuropathies were one of the prerequisites of sexual disorders.

  • PDF