• 디지털융복합연구
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• 제16권9호
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• pp.239-245
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• 2018

현재 일렉트릭 기타 중심의 주류 대중음악 장에서 스티비 레이 본의 위상은 짧은 활동기간에도 불구하고 매우 큰 위치를 차지하는 싱어송 라이터이자 일렉트릭 블루스 기타리스트이다. 그의 영향력은 그만의 독특한 사운드와 폭발적인 무대 퍼포먼스에 이르기까지 현재까지도 많은 기타리스트들의 오마주로 남겨져 있다. 이렇게 끊임없이 재생산 되는 그의 다양한 흔적들 중 연주의 기술적인 부분인 리듬과 솔로 연주를 통해 어떠한 모습으로 나타나는지 살펴보고자 한다. 그의 대표작 중 하나인 'Pride And Joy'를 중심으로 스티비 레이 본이 들려주었던 피킹과 리듬, 스케일 등을 분석하여 그가 영향 받았으며 끊임없이 시도한 변방의 유산인 아프리칸 아메리칸의 블루스를 통해 지금의 주류 대중음악의 장의 중심에 이르기까지 그의 많은 흔적들이 어떠한 모습으로 용해되었고 이를 통해 현재까지도 얼마나 다양한 영향력과 가치를 갖게 될 많은 연구에 앞서 음미해 볼 수 있는 작은 단서가 될 것이라 본다.

• 대한소아치과학회지
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• 제25권4호
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• pp.671-682
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• 1998

Electrophysiological phenomena of pyramidal cells in the CA1 area of the dorsal hippocampus were recorded from and filled with neurobiotin in anesthetized rats. The electropharmacological properties of membrane as well as the cellular-synaptic generation of rhythmic slow activity (theta) were examined. The intracellular response characteristics of these pyramidal cells were distinctly different from responses of interneurons. Pyramidal cells had a high resting membrane potential, a low input resistance, and a large amplitude action potential. A afterhyperpolarization was followed a single action potential. Most of pyramidal cells did not display a spontaneous firing. Pyramidal cells displayed weak inward rectification and anodal break excitation. The slope of the frequency-current relation was 53.4 Hz/nA for the first interspike interval and 15.9 Hz/nA for the last intervals, suggesting the presence of spike frequency adaptation. Neurobiotin-filled neurons showed pyramidal morphology. Cells were generally bipolar dendritc processes ramifying in stratum lacunosum-moleculare, radiatum, and oriens. Commissural stimulation discharged pyramidal cells, followed by excitatory and inhibitory postsynaptic potentials (EPSPs and IPSPs). The frequency of theta-related membrane potential oscillation was voltage-independent in pyramidal neurons. At strong depolarization levels (less than 30 mV) pyramidal cells emitted sodium spike oscillation, phase-locked to theta. The observations provide direct evidence that theta-related rhythmic hyperpolarization of principal cells is brought by the rhythmically discharging interneurons. Furthermore, the findings in which interneurons were also paced by rhythmic inhibitory postsynaptic potentials during theta suggest that they were periodically hyperpolarized by their GABAergic septal afferents.

• The Korean Journal of Physiology
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• 제18권1호
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• pp.19-35
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• 1984

Since the first report of Drury and $Szent-Gy{\ddot{o}}rgyi$ in 1929, the inhibitory influences of adenosine on the heart have repeatedly been described by many investigators. These studies have shown that adenosine and adenine nucleotides have overall depressant effects, similar to those of acetylcholine. Heart beats become slow and weak. It is also well known that adenosine is a potent endogenous coronary vasodilator. Many investigations on the working mechanisms of adenosine have been focused mainly on the effects of the coronary blood flow. However, the cellular mechanisms underlying the inhibitory action of adenosine on sinus node are not well understood yet. Thus, this study was undertaken to examine the behavior of rabbit SA node under influence of adenosine. In these series of experiments three kinds of preparations were used: whole atrial pair, left atrial strip, and isolated SA node preparations. The electrical activity of SA node was recorded with conventional glass microelectrodes 30 to 50 $M{\Omega}$. The preparations were superfused with bicarbonate-buffered Tyrode solution of pH 7.35 and aerated with a gas mixture of $3%\;CO_2-97%\;O_2$ at $35^{\circ}C$. In whole atrial pair, adenosine suppressed sinoatrial rhythm in a dose-dependent manner. Effect of adenosine on atrial rate appeared at the concentration of $10^{-5}M$ and was enhanced in parallel with the increase in adenosine concentration. Inhibitory action of adenosine on pacemaker activity was more prominent in the preparation pretreated with norepinephrine, which can steepen the slope of pacemaker potential by increasing permeability of $Ca^{+2}$. Calcium ions in perfusate slowly produced a marked change in sinoatrial rhythm. Elevation of the calcium concentration from 0.3 to 8 mM increased the atrial rate from 132 to 174 beats/min, but over 10 mM $Ca^{+2}$ decreased. The inhibitory effect of adenosine on sinoatrial rhythm developed very rapidly. Atrial rate was recovered promptly from the adenosine-induced suppression by the addition of norepinephrine, but extra $Ca^{+2}$ was less suitable to restore the suppression of atrial rate. Adenosine suppressed also atrial contractility in the same dosage range that restricted pacemaker activity, even in the reserpinized preparation. In isolated SA node preparation, spontaneous firing rate of SA node at $35^{\circ}C$(mean{\pm}SEM, n=16) was $154{\pm}3.3\;beats/min. The parameters of action potentials were: maximum diastolic potential(MDP), $-73{\pm}1.7\;mV: overshoot(OS), $9{\pm}1.4\;mV: slope of pacemaker potential(SPP), $94{\pm}3.0\;mV/sec. Adenosine suppressed the firing rate of SA node in a dose-dependent manner. This inhibitory effect appeared at the concentration of $10^{-6}M$ and was in parallel with the increase in adenosine concentration. Changes in action potential by adenosine were dose-dependent increase of MDP and decrease of SPP until $10^{-4}M$. Above this concentration, however, the amplitude of action potential decreased markedly due to the simultaneous decrease of both MDP and OS. All these effects of adenosine were not affected by pretreatment of atropine and propranolol. Lowering extra $Ca^{2+}$ irom 2 mM to 0.3 mM resulted in a marked decrease of OS and SPP, but almost no change of MDP. However, increase of perfusate $Ca^{2+}$ from 2 mM to 6 or 8 mM produced a prominent decrease of MDP and a slight increase of OS and SPP. Dipyridamole(DPM), which is known to block the adenosine transport across the cell membrane, definately potentiated the action of adenosine. The results of this experiment suggest that adenosine suppressed pacemaker activity and atrial contractility simultaneously and directly, by decreasing $Ca^{2+}-permeability$ of nodal and atrial cell membranes.

• The Korean Journal of Physiology
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• 제16권2호
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• pp.119-128
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• 1982

The frog truncus arterious were studied with conventional glass microelectrode technique in order to elucidate the underlying mechanism of spontaneous pacemaker activity. The analyses were focussed on the ionic nature of pacemaker current by changing the concentrations of extracellular $K^+$ and, $Na^+$, or by using blockers of K- and Ca-current and chronotropic transmitters. 1) The action potential of the spontaneously active truncus arteriosus has some characteristic feature of maximal distolic potential ranged from -65 to -75 mV, resting potential from -45 to -50 mV and overshoot voltage about +30 mV, respectively. Duration of the action potential taken from rapid upstroke to maximal diastolic potential was about 600 msec. Usual discharge rate was $25{\sim}30/min$ at room temperature $(18{\sim}20^{\circ}C)$. 2) The sensitivity of the resting membrane potential to change extracellular potassium concentrations $(0{\sim}12\;mM)$ was relatively low. Transient hyperpolarization was appeared in the 12 mM K Ringer after 10 min exposure to 0 mM K and it could be related to Na-pump reactivation by high potassium. 3) Reduction of extracellular sodium concetrations diminished the amplitude and frequency of the action potential. In Ringer solution containing 30% Na (substituted by equimolar Tris), spontaneous activity stopped but reappeared as very slow and small action potential. There was no spotaneous activity in zero Na Ringer solution. 4) Caesium(10 mM), K-current blocker decreased the frequency of the action potential and also pacemaker depolarization. Manganese (2 mM) known to be Ca-current antagonist, blocked spontaneous activity completely. 5) Adrenaline and acetylcholine had no chronotropic effect. But adrenaline increased the duration of plateau phase and the magnitude of the action potential in the follower cell. It is concluded that K-, Na-and Ca-current components are involved in the genesis of spontaneous activity of the frog truncus arteriosus like cardiac pacemaker tissues. But the insensitivity of truncus arteriosus to adrenaline and acetylcholine indicates that there are some different control mechanisms of spontaneous rhythm in two tissues.

• 인지과학
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• 제33권1호
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• pp.51-75
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• 2022

경두개 직류전기자극(transcranial Direct Current Stimulation; tDCS)은 지각, 인지, 운동 등의 뇌기능 향상 및 발달 효과가 입증되며, 다양한 분야에서 활용 및 응용되는 비침습적 뇌자극술이다. tDCS 효과는 뇌의 해부학적 구조, 뇌의 노화 정도 등의 뇌신경활성화 특징에 따라 다르게 나타난다는 연구결과들이 보고되고 있다. 일주기 리듬(circadian rhythm)은 대략 하루 주기의 수면과 각성의 생리적 변화패턴을 의미하며 뇌신경활성화 상태는 일주기 리듬에 따라 다르게 나타난다. 일주기 유형(chronotype)은 하루 중에 발현되는 각성도의 크기에 따라 아침의 각성도가 큰 유형은 아침형으로 저녁의 각성도가 큰 유형은 저녁형으로 나누어진다. 본 연구는 일주기 리듬에 의해 변하는 뇌기능 특징이 tDCS 효과에 미치는 영향을 알아보고자 한다. 총 20명의 건강한 성인 대상으로 실험을 진행하였고, 참가자들은 일주기 유형을 분류하기 위해 아침형-저녁형 설문지에 의해 주간형(아침형, 중간형)과 야간형(저녁형)으로 분류했다. 본 실험은 Zoom 프로그램을 이용하여 참가자와 실험자가 온라인으로 만나서 실험을 진행했다. 실험이 확정된 참가자는 실험자로부터 뇌파 기기, 뇌파 데이터를 획득하는 앱이 있는 핸드폰, 핸드폰 거치대, 뇌자극 기기의 사용방법에 대한 설명을 듣고 기기를 테스트해보고 기기를 전달받았다. 기기사용의 어려움을 가진 2명의 참가자는 대면 실험을 진행하여, 실험자가 기기작동을 하여 실험에 참여했다. 일주기 리듬의 상태에 따른 뇌자극 효과를 알아보기 위해 1주일 간격으로 아침과 저녁에 실험했으며, tDCS 자극 전과 후의 신경활성화 반응의 차이를 뇌파를 이용하여 측정하였다. 뇌자극에 의한 뇌기능 변화를 확인하기 위해 자극 전의 뇌파와 자극 후 뇌파가 다른 패턴을 보이며 분류가 잘되는 지를 예측 정확도로 분석했으며, 뇌기능 특징 변화가 일주기 리듬과 일주기 유형에 따라 다르게 나타나는지 확인하기 위해 각 조건의 분류조건(아침/저녁, 주간형/야간형)에서 추출된 주요 EEG 특성을 비교했다. 54개의 뇌파 특성값을 추출하여 SVM(Support Vector Machine) 기계학습 알고리즘으로 분류 모델을 구축하였고, 구축된 모델을 Leave-One-Out 교차검증(Leave-One-Out Cross-Validation)을 사용하여 자극 전과 후의 뇌파 반응을 예측하는지 평가하였고, 분류예측모델의 주요 예측 인자를 확인하는 주요 특성 분석을 진행하였다. 아침과 저녁의 tDCS에 따른 뇌파 특징을 분류하는 예측 정확도는 모두 98%로 나타났으며, 주간형의 아침 자극 조건과 저녁 자극 조건의 예측 정확도는 92%와 96%이며, 야간형의 아침자극 조건과 저녁 자극 조건의 예측 정확도는 모두 94%로 나타났다. 아침 자극 전과 후의 뇌파를 분류하는 상위 3개의 주요 EEG 특성결과는 주간형과 야간형에 따라 다르게 나타났다. 주간형은 좌측 측두 두정엽과 전전두엽의 뇌파 특성값이 나타났으며, 야간형은 측두 두정엽의 뇌파 특성값들만 나타났다. 저녁 자극전과 후의 뇌파를 분류하는 상위 3개의 주요 EEG 특성 결과 또한 주간형과 야간형에 따라 다르게 나타났다. 주간형은 우측 측두 두정엽과 좌측 전두엽의 뇌파 특성값이 나타났으며, 야간형은 측두 두정엽과 전두엽의 뇌파 특성값이 나타났다. 이와 같은 연구결과는 일주기 리듬과 유형에 따라 아침과 저녁의 뇌기능 특징이 다르게 나타나서 뇌자극 효과가 다르게 나타날 수 있음을 확인한 결과이다. 본 연구의 결과는 효과적인 뇌자극을 위해 개인의 뇌신경 활성화 상태 및 특징에 따라서 뇌자극 프로토콜을 조정할 필요성을 제시한다는 데에 의의를 찾을 수 있다.

• 한국엔터테인먼트산업학회논문지
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• 제13권6호
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• pp.25-32
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• 2019

최근 KOFICE의 조사결과에 따라 K-Pop의 인기요인을 추리면 시각요소와 청각요소로 나뉘며 청각요소의 비중이 큰 것을 확인할 수 있다. 다양한 가수형태 중에서 아이돌이 K-Pop을 주도하고 있으며, 연구 대상으로 2018년 선호하는 K-Pop 가수에서 여자그룹부문 1위를 차지한 블랙핑크를 선정하였다. 더불어 블랙핑크의 활동기간과 비슷한 트와이스의 음악을 비교 연구범위로 정했다. 두 그룹의 음악에서 나타난 공통점은 선율과 화성리듬을 중심으로 구현된 후렴구와 리듬구조가 있으며, 장조와 단조의 사용빈도는 큰 차이를 보인다. 이를 선법과 모달 인터체인지를 통해, 2016년에서 2018년까지 발매된 상위권의 K-Pop을 분석한다. 연구결과 첫 번째, 한 개 이상의 선법이 중심선율로 사용된다. 두 개 이상 선법이 사용될 시 같은 계열의 다른 선법이 노래의 기능적 형식에 따라 변한다. 두 번째, 보컬과 악기로 표현한 선율의 리듬은 2마디 패턴을 기준으로 반복한다. 마지막으로 화음을 적게 사용하고, 화성리듬을 느리게 표현할 때 화음 성질을 결정짓는 3음을 생략하거나 변형하는 방식이 나타난다. 본 연구결과를 통해, 장조와 단조에 따라 선법과 모달 인터체인지의 사용형태가 나뉘는 것을 알 수 있다.

• Clinical and Experimental Pediatrics
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• 제52권7호
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• pp.752-755
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• 2009

It is well known that hemodynamic load is one of the most important determinants of cardiac structure and function. Circadian variations in blood pressure (BP) are usually accompanied by consensual changes in peripheral resistance and/or cardiac output. In recent years, reduction in circadian variations in BP and, in particular, loss of nocturnal decline of BP were observed in hypertensive patients with left ventricular hypertrophy (LVH). The patients with only a slight or no loss of nocturnal decline of BP were considered "non-dippers". Regression of LVH was observed after prolonged antihypertensive therapy. Restoration of the circadian rhythm of BP was also observed. However, the classification of patients into "dippers" and "non-dippers" is arbitrary and poorly standardized and repeatable, and in the recent studies, most hypertensive patients with LVH were "dippers". Therefore, we should be particularly cautious about the conclusions drawn using this index. On the other hand, reduced activity of low-pressure cardiopulmonary baroreceptors and impaired day-to-night modulation of autonomic nervous system activity were observed in patients with only LVH. Therefore, alterations in cardiac structure may impair BP modulation. On the other hand, the reverse can also be trueprimary alterations in BP modulation, through a persistently elevated afterload, can increase cardiac mass. Thus, the interrelationship between cardiac structure and BP modulation is complex. Hence, new and more specific methods of evaluating circadian changes in BP are needed to better clarify the abovementioned reciprocal influences.

• The Journal of Korean Physical Therapy
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• 제29권1호
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• pp.27-32
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• 2017

Purpose: Recent electrophysiological studies have shown that the sensorymotor cortex is activated during both actual action excuted by themselves and observation of action performed by other persons. Observation of action based on mirror neuron system can be used as a cognitive intervention to promote motor learning. The purpose of this study was to investigate the brain activity changes during action observation and action execution using EEG. Methods: Thirty healthy volunteers participated and were requested to perform hand action and to observe the video of hand action performed by another person. The EEG activity was evaluated by a method which segregated the time-locked for each condition. To compare the differences between action observation and execution, the Mu suppression and the relative band power were analysed. Results: The results showed significant mu suppression during the action observation and execution, but the differences between the two conditions were not observed. The relative band power showed a significant difference during the action observation and execution, but there were no differences between the two conditions. Conclusion: These results indicate that action execution and observation involve overlapping neural networks in the sensorymotor cortical areas, proposing positive changes on neurophysiology. We are expected to provide information related to the intervention of cognitive rehabilitation.

• 대한물리의학회지
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• 제13권1호
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• pp.1-9
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• 2018

PURPOSE: This study investigated the neurophysiological and behavioral adaptation during one or both hands movement in chronic stroke patients. METHODS: The study included sixteen hemiplegic stroke patients. Neurophysiological data (brain activation and muscle activation) were examined by electroencephalography (EEG) and electromyography (EMG), and behavioral adaptation was examined by wrist extension angle during wrist extension with one hand or both hands. Outcome variables of one hand or both hands were; mu rhythm of the EEG, EMG amplitude of wrist extensor and flexor muscles, and wrist angle of Myomotion 3D motion analysis. RESULTS: Our results revealed that wrist extension angle was significant increased during both hands movement compared to one hand movement (p<.05). Furthermore, in affected sensorimotor area, there was significant increase in the brain activation during both hands movement compared to one hand movement (p<.05). However, there was no significant different between one hand and both hands movement in muscle activation (p>.05). CONCLUSION: According to the findings of this experiment, bilateral arm movement improved brain activity on affected sensorimotor area and wrist extension angle. Therefore, we suggest that bilateral arm movement would positive effect on stroke rehabilitation in terms of increase in brain activation on affected motor area and wrist extension during bilateral arm movement.

• 대한의용생체공학회:의공학회지
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• 제29권1호
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• pp.17-24
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• 2008

The aim of this paper is to report our preliminary results of investigating the spatial focalization of Zen-meditation EEG (electroencephalograph) in alpha band (8-13 Hz). For comparison, the study involved two groups of subjects, practitioners (experimental group) and non-practitioners (control group). To extract EEG alpha rhythm, wavelet analysis was applied to multi-channel EEG signals. Normalized alpha-power vectors were then constructed from spatial distribution of alpha powers, that were classified by Fuzzy C-means based algorithm to explore various brain spatial characteristics during meditation (or, at rest). Optimal number of clusters was determined by correlation coefficients of the membership-value vectors of each cluster center. Our results show that, in the experimental group, the incidence of frontal alpha activity varied in accordance with the meditation stage. The results demonstrated three different spatiotemporal modules consisting with three distinctive meditation stages normally recognized by meditation practitioners. The frontal alpha activity in two groups decreased in different ways. Particularly, monotonic decline was observed in the control group, and the experimental group showed increasing results. The phenomenon might imply various mechanisms employed by meditation and relaxation in modulating parietal alpha.