• 제목/요약/키워드: Threshold stimulus

검색결과 68건 처리시간 0.021초

마취된 흰 쥐 시상의 복후내측핵내 유해성 뉴론의 특성 (RESPONSE CHARACTERISTICS OF VENTRAL POSTEROMEDIAL THALAMIC NOCICEPTIVE NEURONS IN THE ANESTHETIZED RAT)

  • 이형일;박수정
    • Restorative Dentistry and Endodontics
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    • 제27권6호
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    • pp.587-599
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    • 2002
  • Extracellular single unit recordings were made from the ventral posteromedial thalamic (VPM) nociceptive neurons to determine mechanoreceptive field (RF) and response properties. A total of 44 VPM thalamic nociceptive neurons were isolated from rats anesthetized with urethane-chloralose. Based on responses to various mechanical stimuli including touch, pressure and pinch applied to the RF, 32 of 44 neurons were classified as nociceptive specific (NS) neuron. The other 12 neurons, classified as wide dynamic range (WDR), showed a graded response to increasingly intense stimuli, with a maximum discharge to noxious pinch. The VPM nociceptive neurons showed various spontaneous activity ranged from 0-6 Hz. They were located throughout the VPM, and had an contralateral RF including mainly intraoral (and perioral) regions. The RF size was relatively small, and very few neurons had a receptive field involving 3 trigeminal divisions. The NS neurons activated only by pressure and pinch stimuli had high mechanical thresholds compared to WDR neurons activated also by touch stimuli. The VPM nociceptive neurons were tested with suprathershold graded mechanical stimuli. Most of 21 NS and 8 WDR neurons showed a progressive increase in number of spikes as mechanical stimulus intensity was increased. In some neurons, the responses reached a peak before the highest intensity was given. Application of 5 mM $CoCl_2{\;}(10{\;}{\mu}\ell)$ solution to the trigeminal subnucleus caudalis did not produce any significant changes in the spontaneous activity, RF size, mechanical threshold, and response to suprathreshold mechanical stimuli of 9 VPM nociceptive neurons tested. 17 of 33 VPM nociceptive neurons responded to noxious heat as well as noxious mechanical stimuli applied to their RF. Application of the mustard oil, a small-fiber excitant and inflammatory irritant, to the right maxillary first molar tooth pulp induced an immediate but short-lasting neuronal discharges upto approximately 4 min in 16 of 42 VPM nociceptive neurons. These results suggest that VPM thalamic nucleus may contribute to the sensory discriminative aspect of orofacial nociception.

시각과 운동의 뇌기능영상 : 자극에 따른 총활성화의 차이 (fMRI of Visual and Motor Stimuli : Difference of Total Activation Depends on Stimulation Paradigm)

  • 정순철;송인찬;장기현;유병기;문치웅;조장희
    • Investigative Magnetic Resonance Imaging
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    • 제3권1호
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    • pp.41-46
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    • 1999
  • 목적 : 뇌기능 영상을 이용하여 자극에 따른 시각영역, 운동영역 및 소뇌에서의 총활성화의 차이를 연구하고자 하였다. 대상 및 방법 : 건강한 5명의 피실험자를 대상으로 EP 기법을 이용하여 시각자극과 운동자극에 의한 피질활성화 검사를 시행하였다. 시각피질 활성화를 위해서는 LED 자극과 Checker-Board 자극을 각각 행하였고, 운동피질과 소뇌의 활성화를 위해서는 엄지손가락 운동과 네 손가락을 엄지 손가락과 순서대로 마주치게 하는 운동을 시행하였다. 각각의 자극은 60초의 휴식기, 120초의 자극기 및 운동기, 다시 60초의 휴식기로서 시행하였다. 데이터 처리는 cros-correlation 방법으로 통게처리 하였고, 적절한 문턱 값 이상을 가지는 화소를 활성화 화소로 정의하였다. 이 활성화 화소의 수와 신호변화율의 곱으로서 총활성화의 시간축 데이타를 완성하였다. 결과 : 시각피질에서의 총활성화는 Checker-Board 자극에 비해 LED 자극을 가했을 때 100% 이상 증가하였다. 엄지 손가락 운동에 비해 손가락 마주치기 운동을 시행했을 때 총활서와는 운동피질에서 100% 이상 증가하였고, 소뇌에서는 150% 이상 증가하였다. 결론 : 시각 및 운동자극의 변화에 따라 시각영역, 운동영역 및 소뇌에서의 총활성화가 차이를 보이는 것을 확인할 수 있었다.

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고지방 식이 섭취 소동물 모델을 활용한 전신진동 자극의 복부 지방 감소 효능 평가 (The Effects of Whole Body Vibration in the Aspect of Reducing Abdominal Adipose Tissue in High-Fat Diet Mice Model)

  • 황동현;김서현;이한아;이상엽;서동현;조승관;천슬기;한태영;김한성
    • 대한의용생체공학회:의공학회지
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    • 제38권1호
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    • pp.49-55
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    • 2017
  • The prevalence of obesity has noticeably increased worldwide over several decades with various complication. Even though anti-obesity drug treatments have been spotlighted by resulting in effective mean weight losses, its adverse effects cannot be overlooked. Thus, this study aimed to evaluate the effects of multi-frequency whole body vibration, one of the mechanical stimulus, as a countermeasure against obesity. Thirty-two-6-week-old C57BL/6J male mice were equally assigned to four groups: the Control group (CON, n = 8), the Sham group (Sham, n = 8), the sham with single frequency whole body vibration (S+V, n = 8), and the sham with multi frequency whole body vibration (S+MV, n = 8). After 4 weeks, morphologic changes in the adipose tissue were evaluated from three-dimensional images using in vivo micro-computed tomography. At 4 weeks, the volume of the abdominal adipose tissue, which had the highest value in Sham group, noticeably reduced in S+MV group compared to it in S+V group. These results implied that the accumulation of abdominal adipose tissue can be effectively reduced through applying multi-frequency whole body vibration.

구형파 변조된 경두개 자기자극을 이용한 쥐의 감각피질 자극실험 (Mouse Somatosensory Cortex Stimulation Using Pulse Modulated Transcranial Magnetic Stimulation)

  • 선석규;서태윤;허여울;조제원;권영우
    • 한국전자파학회논문지
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    • 제27권5호
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    • pp.482-485
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    • 2016
  • 본 논문에서는 쥐 뇌의 감각 피질을 자극하기 위해 변조신호를 이용하여 경두개 자기자극(TMS) 동물실험을 수행하였다. 제안한 TMS 시스템은 인버터, 변압기, 커패시터, 가변 인덕터, 자극 코일로 구성되어 쥐 뇌의 감각피질에 약 1.5 mT의 자기장이 생기도록 시스템을 설계하였다. 자극 신호는 구형파 변조되었으며, 반송 주파수는 85~91 kHz의 범위로 변화시키며, 자극 효과를 관찰하였다. 자극 결과 반송 주파수가 89 kHz 미만일 때에는 자극의 효과를 볼 수 없었고, 반송 주파수가 89 kHz 이상일 때에는 압력 자극에 반응하는 역치 값이 낮아지는 효과를 볼 수 있었다.

측방 눈 주시가 유발이음향방사 청각기능에 미치는 영향 (The Effects of Eye Lateralization on Transient Evoked Otoacoustic Emissions of Auditory Function)

  • 주석희
    • 대한통합의학회지
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    • 제7권4호
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    • pp.131-140
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    • 2019
  • Purpose : The purpose of this study was to investigate the interrelationship between eye movement and auditory function through the effects of eye lateralization on transient evoked otoacoustic emissions of auditory function. Methods : 25 subjects with complete set of ears were used in this study, which composed of 12 males and 13 females with pure tone threshold of below 25 dB without otolaryngology were evaluated. Each of the patient has a visual acuity of greater than 1.0 after correction, and has no problems with eye disease, eye movement, and human parallel system. In a dark silent room, the subjects sat on a chair with their heads fixed on a headrest. The tests were performed by asking the patients to look at a fixed red light dot on a light bar in front of them. This light was directed to the front, right and left sides of the subject at an angle of 40 ° In the presence of the stimulus sound in the ipsilateral ear, the transient evoked otoacoustic emissions of the ipsilateral ear was measured at the straight, right and left fixation. In order to evaluate the transient evoked otoacoustic emissions through the efferent auditory pathway, the transient evoked otoacoustic emission values of the contralateral ear were measured at the straight, right and left fixation. These measurements were taken at frequencies of 1 kHz, 1.4 kHz, 2.0 kHz, 2.8 kHz and 4 kHz, respectively. Results : Transient evoked otoacoustic emissions caused by lateral movement of the eye showed significant changes at 1.4 KHz and 2 KHz of the afferent pathway of the ipsilateral ear. Also, significant changes were observed at 1.4 KHz and 4 KHz of the efferent pathway of the contralateral ear. Conclusion : These results indicated that there is a close relationship between eye movement and auditory cochlea. In the future, further studies considering more diverse subjects and age groups will be needed.

조피볼락의 청각문턱치 (Auditory Thresholds of Black Rock Fish)

  • 박용석;이창헌;문종욱;안장영;서두옥
    • 수산해양교육연구
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    • 제11권1호
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    • pp.88-97
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    • 1999
  • 해양목장에서의 음향순치의 기초 자료로 얻기 위하여 조피볼락 Sebastes schlegeli을 대상어종으로 80~800 Hz의 수중음과 DC 8V의 전기자극으로 조건학습시켜 조피볼락의 심박간격의 변화로부터 조피볼락이 지각할 수 있는 최소음압올 판단해서 주파수별로 청각문턱치를 구하였다. 그 결과 조피볼락은 측정한 80~800 Hz의 각 주파수에서 대해서 반용올 보여, 2차곡선 모양의 청각문턱치곡선 형상올 보이고 있었으며, 조피볼락의 평균 청각문턱치는 측정 주파수중 100 Hz에서 가장 민감하게 나타났다. 청각문턱치는 주파수가 300 Hz에서 500 Hz로 변화할 때 현저하게 증가하였으며, 조건학습 과정에서도 80~200 Hz의 순음에 대해서는 순음과 전기자극에 대한 조건학습으로부터 순음을 지각하면 방음과 동시에 심박간격이 현저하게 벌어지는 현상이 나타난 반면에 300 Hz 이상의 순음에서는 여러 번의 방성과 전기자극에 의한 조건학습이 쉽게 이뤄지지 않아, 조피볼락의 청각은 200 Hz 이하의 저주파수의 순음에 민감한 반면 주파수가 높아질수록 실험어가 수중음을 지각하기 어려운 것으로 나타났다.

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효과적인 대뇌 직접피질자극 검사 및 피질하자극 검사의 술기에 관한 기술적 고찰 (Technical Considerations of Effective Direct Cortical and Subcortical Stimulation)

  • 임성혁;장민환
    • 대한임상검사과학회지
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    • 제54권2호
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    • pp.157-162
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    • 2022
  • 본 술기의 목적은 운동피질 주변에 발생한 뇌종양 환자의 수술에서 TceMEP로 인해 발생하는 위양성을 방지하고 수술 중 운동영역의 정확한 매핑과 피질척수로 보존하기 위함이다. 또한 검사과정에서 발생하는 시행착오를 줄이고 검사시간을 최소화하여 검사결과에 대한 빠른 피드백으로 수술하는 의사에게 정확한 정보를 전달함에 있다. 본 술기의 가장 중요한 요소는 첫번째로 일정 세기의 자극역치로 검사해야 하는 것과 두번째로는 일정 수준의 마취농도를 적정 수준으로 유지하는 것이 수술 중 발생하는 위양성을 막는 기본적이 요소이다. 세번째로는 수술하는 반대쪽 부위에 다중 채널을 이용한 기록전극의 설치로 최대한 많은 근육에서 TceMEP파형과 집접피질자극 및 직접피질하 자극에 대한 반응을 측정하는 것이다. 이런 조건들이 수술이 진행되는 동안 원활하게 유지된다면 검사에서 오는 위양성이 아닌 그 밖의 요인들에서 발생할 수 있는 원인들을 예측할 수 있다.

Gaps-In-Noise Test Performance in Children with Speech Sound Disorder and Cognitive Difficulty

  • Jung, Yu Kyung;Lee, Jae Hee
    • Journal of Audiology & Otology
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    • 제24권3호
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    • pp.133-139
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    • 2020
  • Background and Objectives: The Gaps-In-Noise (GIN) test is a clinically effective measure of the integrity of the central auditory nervous system. The GIN procedure can be applied to a pediatric population above 7 years of age. The present study conducted the GIN test to compare the abilities of auditory temporal resolution among typically developing children, children with speech sound disorder (SSD), and children with cognitive difficulty (CD). Subjects and Methods: Children aged 8 to 11 years-(total n=30) participated in this study. There were 10 children in each of the following three groups: typically developing children, children with SSD, and children with CD. The Urimal Test of Articulation and Phonology was conducted as a clinical assessment of the children's articulation and phonology. The Korean version of the Wechsler Intelligence Scale for Children-III (K-WISC-III) was administered as a screening test for general cognitive function. According to the procedure of Musiek, the pre-recorded stimuli of the GIN test were presented at 50 dB SL. The results were scored by the approximated threshold and the overall percent correct score (%). Results: All the typically developing children had normal auditory temporal resolution based on the clinical cutoff criteria of the GIN test. The children with SSD or CD had significantly reduced gap detection performance compared to age-matched typically developing children. The children's intelligence score measured by the K-WISC-III test explained 37% of the variance in the percent-correct score. Conclusions: Children with SSD or CD exhibited poorer ability to resolve rapid temporal acoustic cues over time compared to the age-matched typically developing children. The ability to detect a brief temporal gap embedded in a stimulus may be related to the general cognitive ability or phonological processing.

Gaps-In-Noise Test Performance in Children with Speech Sound Disorder and Cognitive Difficulty

  • Jung, Yu Kyung;Lee, Jae Hee
    • 대한청각학회지
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    • 제24권3호
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    • pp.133-139
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    • 2020
  • Background and Objectives: The Gaps-In-Noise (GIN) test is a clinically effective measure of the integrity of the central auditory nervous system. The GIN procedure can be applied to a pediatric population above 7 years of age. The present study conducted the GIN test to compare the abilities of auditory temporal resolution among typically developing children, children with speech sound disorder (SSD), and children with cognitive difficulty (CD). Subjects and Methods: Children aged 8 to 11 years-(total n=30) participated in this study. There were 10 children in each of the following three groups: typically developing children, children with SSD, and children with CD. The Urimal Test of Articulation and Phonology was conducted as a clinical assessment of the children's articulation and phonology. The Korean version of the Wechsler Intelligence Scale for Children-III (K-WISC-III) was administered as a screening test for general cognitive function. According to the procedure of Musiek, the pre-recorded stimuli of the GIN test were presented at 50 dB SL. The results were scored by the approximated threshold and the overall percent correct score (%). Results: All the typically developing children had normal auditory temporal resolution based on the clinical cutoff criteria of the GIN test. The children with SSD or CD had significantly reduced gap detection performance compared to age-matched typically developing children. The children's intelligence score measured by the K-WISC-III test explained 37% of the variance in the percent-correct score. Conclusions: Children with SSD or CD exhibited poorer ability to resolve rapid temporal acoustic cues over time compared to the age-matched typically developing children. The ability to detect a brief temporal gap embedded in a stimulus may be related to the general cognitive ability or phonological processing.

Long-term consistency of clinical sensory testing measures for pain assessment

  • Pablo Bellosta-Lopez;Victor Domenech-Garcia;Thorvaldur Skuli Palsson;Pablo Herrero;Steffan Wittrup Mcphee Christensen
    • The Korean Journal of Pain
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    • 제36권2호
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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.