• The Korean Journal of Physiology and Pharmacology
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• 제10권6호
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• pp.303-307
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• 2006

The effects of ethanol on corticostriatal synaptic transmission were examined, using extracellular recording and analysis of population spike amplitudes in rat brain slices, to study how acute ethanol intoxication impairs striatal function. Ethanol caused a decrease in population spike amplitudes in a dose dependent manner ($50{\sim}200mM$). Pretreatment with picrotoxin, a ${\gamma}-amino$ butyric acid $(GABA)_{A}$ receptor antagonist, increased the population spikes but ethanol (100 mM) was still effective in decreasing the population spikes under this condition. In the presence of $_{(DL)}-2-amino-5-phosphonovaleric$ acid (APV), N-methyl-D-aspartate (NMDA) receptor antagonist, the inhibitory action of ethanol on population spikes was not shown. These results suggest that ethanol inhibits the glutamatergic corticostriatal synaptic transmission through blockade of NMDA receptors.

• 대한소아치과학회지
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• 제27권1호
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• pp.7-14
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• 2000

가바성 억제 신경세포는 해마의 정상적인 기능을 조절하는데 중요한 역할을 하며 해마 병변을 유발하는 중요한 요소이다. 본 연구는 in vivo 실험법을 사용하여 해마 CA1 영역에서의 전기 생리학적 반응을 측정함으로써 가바성 신경세포의 기능을 분석하고 이를 슬라이스 실험법과 비교하고자 하였다. Fimbria-fonix 전기자극시 전형적인 population spike가 나타났고 $10{\sim}M$ bicuculline 존재하에서는 전기자극에 의해 burst 형태의 population spike가 나타났다. Population spike의 크기는 자극 강도에 비례하였으며 그 숫자도 bicuculline 전극사용시와 같이 동일한 양상을 보였다. CA1 영역의 흥분성 수준을 측정하기 위해 paired-pulse 자극을 하였는데 짧은 자극 간격에서 억제성 반응을 보였고 burst형태의 afterdischarge를 나타내었다. CA1 영역에서 in vivo실험법을 사용한 가바성 신경세포반응의 결과는 추체세포의 흥분성 조절을 효과적으로 분석할 수 있으며 in vitro 실험법에 비해 기능적 평가가 더욱 이상적임을 알 수 있다.

• 대한의용생체공학회:의공학회지
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• 제38권6호
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• pp.342-351
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• 2017

뉴럴 디코딩은 뉴론이 발화한 스파이크 트레인으로부터 뉴론에 인가된 원 자극을 추정하는 작업을 말한다. 디코딩은 뉴론들끼리 어떻게 신호를 주고 받는 지를 이해함으로써 궁극적으로 뇌가 어떻게 정보처리를 하는 지 이해하는 기초적인 작업이다. 이 논문에서 우리는 3가지 뉴럴 디코딩 방법, 즉 빈도 디코딩, 시간 디코딩, 군집 디코딩 방법에 대해 설명하겠다. 빈도 디코딩은 자극에 대한 스파이크의 발화빈도 정보를 이용하여 자극을 복원하는 방법을 말한다. 역사적으로 가장 먼저 시도되었고 가장 간단한 디코딩 방법이다. 그러나 정수 개인 스파이크 개수로부터 빈도를 계산하는 과정에서 빈도자체가 불연속이고 양자화될 가능성이 높기 때문에 간단하고 정적인 자극이 아닌 경우 빈도 디코딩으로는 자극을 복원하기 어렵다는 한계를 가지고 있다. 시간 디코딩은 스파이크 발생 빈도가 아닌 개별 스파이크들의 발생시각을 이용한 디코딩 방법을 말하며 실제 빠르게 변화하는 자극의 경우 신경세포는 빈도 디코딩이 아니라 시간 디코딩을 통해 자극을 추정하는 것으로 이해되고 있다. 군집 디코딩은 단일 신경세포가 아닌 군집 신경세포로부터 자극을 복원하는 방법이다. 군집 디코딩은 단일 신경 세포 디코딩에 비해 신경 세포의 가변성에 따른 불확실성을 감소시킬 수 있고 서로 다른 자극의 특성을 동시에 표현할 수 있다는 장점을 갖는다. 이 논문에서는 먼저 세 가지 뉴럴디코딩 방법에 대해 소개하고 정보이론이 뉴럴디코딩에 어떻게 적용되는 지를 다룬 후 마지막으로 최근에 각광받고 있는 기계학습 방법에 의한 뉴럴 디코딩에 대해 다루도록 하겠다.

• The Korean Journal of Physiology and Pharmacology
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• 제10권1호
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• pp.13-17
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• 2006

Experimentally induced cortical disorganization exhibits many anatomical features which are characteristic of cortical malformations in children with early-onset epilepsy. We used an immunocytochemical technique and extracellular field potential recordings from the dorsal hippocampus to determine whether the excitability of the CA1 pyramidal cells was enhanced in rats with exnerimentallv induced hippocampal dysplasia. Compared with control rats, the MAM-treated rats displayed a decrease of paired pulse inhibition. When $GABA_A$ receptor antagonists were blocked with $10{\mu}M$ bicuculline the amplitude of the second population spike of the MAM-treated of rats was similar to that of the first population spike, as was in the control rats. The MAM-treated rats had fewer somatostatin and parvalbumin-immunoreactive neurons than the control rats. These results suggest that the enhanced neuronal responsiveness of the in vivo recording of the CA1 in this animal model may involve a reduction of CA1 inhibition.

• 수면정신생리
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• 제2권2호
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• pp.133-137
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• 1995

The author reviews current knowledge about what REM sleep is and where and how it is generated. REM sleep is the state in which our most vivid dreams occur. REM sleep is identified by the simultaneous presence of a desynchronized cortical EEG, an absence of activity in the antigravity muscles(atonia), and periodic bursts of rapid eye movements. Another characteristic phenomena of REM sleep are the highly synchronized hippocampal EEG of theta frequency and the ponto-geniculo-occipital(PGO) spike. All these phenomena can be explained in terms of changes in neuronal activity. Transection studies have determined that the pons is sufficient for generating REM sleep. Lesion studies have identified a small region in the lateral pontine tegmentum corresponding to lateral portions of the nucleus reticularis pontis oralis(RPO) and the region immediately ventral to the locus coeruleus, which is required for REM sleep. Unit recording studies have found a population of cells within this region that is selectively active in REM sleep. Cholinergic neurons of the giant cell field of pontine tegmentum(ETG), which is 'REM a sleep-on cells', has shown to be critically involved in the generation of REM sleep. Noradrenergic neurons of the locus coeruleus and serotonergic neurons of the dorsal raphe, which are called 'REM sleep-off cells', appear to act in a reciprocal manner to the cholinergic neurons. It is proposed that the periodic cessations of discharge of 'REM sleep-off cells' during REM sleep might be significant for the prevention of the desensitization of receptors of these neurons.

• Animal cells and systems
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• 제13권4호
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• pp.357-362
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• 2009

Hesperidin, the most abundant polyphenolic compound found in citrus fruits, has been known to possess neuroprotective, sedative, and anticonvulsive effects on the nervous system. In a recent electrophysiological study, it was reported that hesperidin induced biphasic change in population spike amplitude in hippocampal CA1 neurons in response to both single spike stimuli and theta-burst stimulation depending on its concentration. However, the precise mechanism by which hesperidin acts on neuronal functions has not been fully elucidated. Here, using whole-cell patch-clamp recording, we revealed that hesperidin did not affect excitatory synaptic activities such as basal synaptic transmission and theta-burst LTP. Moreover, in a current injection experiment, spike number, resting membrane potential and action potential threshold also remained unchanged. Taken together, these results indicate that the effects of hesperidin on the neuronal functions such as spiking activity might not be attributable to either modification of excitatory synaptic transmissions or changes in membrane excitability in hippocampal CA1 neuron.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2007년도 한국컴퓨터종합학술대회논문집 Vol.34 No.1 (B)
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• pp.5-8
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• 2007

본 논문은 스파이크 뉴런의 응답 모델에 대하여 논의한다. 먼저, 스파이크 뉴런의 코딩 방법과 스파이크 기능에 대하여 논의하고, 커널 함수의 중첩(superposition)에 의한 스파이크 뉴런의 활동 전위 구성에 대하여 논의한다. 이 방법은 IF(Integrate-and-Fire) 뉴런 모델에서 사용하는 활동 전위 방정식보다 일반적인 것이라는 것을 설명하였다. 다음에 스파이크 출력의 기능으로서 우연성 동시 검출과 가중치 계산을 논의하고 뉴런 집단(population)의 스파이크 출력에 대하여 논의한다.

• Clinical and Experimental Vaccine Research
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• 제13권1호
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• pp.63-67
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• 2024

This repeated cross-sectional study with two independent sample populations compared the antibody response to severe acute respiratory syndrome coronavirus 2 vaccines in Albania in July-August 2021 and 2022. In 2021, it found higher anti-spike-1 seropositivity and antibody levels in fully vaccinated individuals, especially with BNT162b2 and ChAdOx1 and to a lesser degree with CoronaVac. By 2022, all single-dose recipients showed high antibody responses, suggesting natural infection-enhanced immunity. The study indicates a significant evolution in the antibody response to different coronavirus disease 2019 vaccines and suggests that a single vaccine dose, coupled with natural infection, might suffice to maintain adequate immunity levels in an endemic scenario.

• International Journal of Oral Biology
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• 제31권2호
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• pp.33-43
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• 2006

Dysplasia-associated seizure disorders are markedly resistant to pharmacological intervention. Relatively little research has been conducted studying the effects of antiepileptic drugs(AEDs)on seizure activity in a rat model of dysplasia. We have used rats exposed to methylazoxymethanol acetate(MAM) in utero, an animal model featuring nodular heterotopia, to investigate the effects of AEDs in the dysplastic brain. Pilocarpine was used to induce acute seizure in MAM-exposed and age-matched vehicle-injected control animals. Field potential recordings were used to monitor amplitude and numbers of population spikes, and paired pulse inhibition in response to stimulation of commissural pathway. Two commonly used AEDs were tested: diazepam 5, 2.5 mg/kg; phenytoin 40, 60 mg/kg. Diazepam(DZP) and phenytoin(PHT) reduced the amplitude of population spike in control and MAM-exposed rats. However, the amplitude of population spike was nearly eliminated in control rats as compared to the MAM-exposed rats. Pharmaco-resistance was tested by measuring seizure latencies in awake rats after pilocarpine administration(320 mg/kg, i.p.) with and without pretreatment with AEDs. Pre-treatment with PHT 60 mg prolonged seizure latency in control rats, but not in MAM-exposed animals. The main findings of this study are that acute seizures initiated in MAM-exposed rats are relatively resistant to standard AEDs assessed in vivo. These data suggest that animal model with cortical dysplasia can be used to screen the effects of potential AEDs.

• Journal of Korean Neurosurgical Society
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• 제29권9호
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• pp.1161-1170
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• 2000

Objective : The transverse hippocampal slice is one of the most commonly studied in vitro models of mammalian brain physiology. However, despite its broad usage, there has been no standardization of slice preparation techniques or recording condition. It is well known that variations in recording conditions can result in profound different effects to neuronal responses. Evoked field potentials, recorded extracellularly, were used to investigate the effects of variations in hippocampal slice preparation protocol on hypoxia responses of CA1 neurones. Material & Methods : Before hypoxic injury, hippocampal slices were incubated for 4 hours. During incubation period, the slices were placed in a incubation chamber($21^{\circ}C$) for recovery from preparation injury and then transferred to recording chamber($34^{\circ}C$) for more recovery and baseline electric recording with current stimulation(0.1Hz). Various time periods in incubation chamber and recording chamber were applied to each experimental group(group 1=60min : 180min, group 2=90min : 150min, group 3=180min : 60min, time in incubation chamber : time in recording chamber) before 10 min hypoxia produced by replacing 95% $O_2$+5% $CO_2$ mixed gas to 95% $N_2$+5% $CO_2$ gas. Calcium, Magnesium ions and several drugs effecting on glutamate receptor also were studied. Recoveries from hypoxic injury of hippocampal slices were estimated by percent recovery of population spike(PS). Statistic analysis of study were performed using paired t-test. Results : The percent recovery of PS after 10min hypoxia was considerably enhanced by increasing the period of current stimulation during incubation period before hypoxic injury. Temperature effect on the result of this experiment was also studied(group 4) but the result from this showed no statistic significance. Low magnesium ion concentration of artificial CSF(Mg-free aCSF) during incubation period enhanced the recovery of PS but low calcium (calcium-free) and high magnesium ion concentration(2mM) reduced it after hypoxic injury. L-glutamate($100{\mu}M$) and AP-5($50{\mu}M$) had no effect on the recovery of PS but CNQX($10{\mu}M$) in artificial CSF during incubation period markedly enhanced the recovery of PS. Co-treatment of AP-5($50{\mu}M$), CNQX($10{\mu}M$) and high magnesium concentration(2mM) enhanced recovery of PS in immediate following period of hypoxic injury but the effect of cotreatment after then decayed rapidly and lost statistic significance. Conclusions : Judging from above results, the condition of baseline recording is important in observing the recovery of population spike after hypoxia, and the time and the condition should be controled more strictly to obtain reliable results.