• Korean Journal of Cognitive Science
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• v.10 no.4
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• pp.41-50
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• 1999

It is widely known that the hippocampus plays an important role in spatial memory. Recent studies have suggested that the posterior parietal cortex (PPC) is involved in spatial memory. However it is unclear whether the PPC is involved in w working memory or reference memory of spatial learning. The purpose of the present study was to determine contribution of the hippocampus and the PPC to spatial working memory and acquisition of reference memory. Using an eight-arm radial maze in which e each arm was baited. working memory was tested by measuring rat's ability to remember arms they had visited. Reference memory was tested by measuring rat's ability to avoid visiting four consistently unbaited arms. Effects of hippocampal or PPC lesion on working memory or acquisition of reference memory in radial-arm maze learning were investigated Working memory was impaired by hippocampal lesion whereas not affected by PPC lesion. Acquisition of reference memory was impaired by lesion in either site. The results suggest that the hippocampus plays an important role in the spatial working memory while both the hippocampus and the PPC contribute to the acquisition of spatial reference memory.

• Journal of the Korean Society for Library and Information Science
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• v.49 no.1
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• pp.443-464
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• 2015

This study examined the feasibility of using EEG signals and ERP P3b for extracting video key-frames based on users' cognitive responses. Twenty participants were used to collect EEG signals. This research found that the average amplitude of right parietal lobe is higher than that of left parietal lobe when relevant images were shown to participants; there is a significant difference between the average amplitudes of both parietal lobes. On the other hand, the average amplitude of left parietal lobe in the case of non-relevant images is lower than that in the case of relevant images. Moreover, there is no significant difference between the average amplitudes of both parietal lobes in the case of non-relevant images. Additionally, the latency of MGFP1 and channel coherence can be also used as criteria to extract key-frames.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2003.05a
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• pp.107-110
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• 2003

본 연구에서는 EEG를 이용하여 정신집중 시, 뇌 기능의 변화를 알아보았다. 실험은 건강한 남녀 고교생 9명을 대상으로 EEG는 Fp1. Fp2, F3, F4, P3, P4, T5, T6, O1, O2의 10위치에 대하여 정신집중 작업 진의 3분과 작업 시 30분간을 측정하였다. 작업은 PC를 이용하였으며 모니터 상의 움직임에 집중하고 목표자극을 탐지하였을 때 신속하게 적절한 반응키를 누르도록 하였다. 각 주파수 대역은 theta2와 (6.0-8.0Hz), alpha1파 (8.0-10.0Hz), alpha2파(10.0-12.0Hz)로 구분하였으며 비대칭지수를 이용하여 분석하였다. 그 결과, 정신집중 작업 시 theta1, theta2, alpha1대역에서 두정엽의 우반구과 측두엽 및 후두엽의 좌반구영역이 우세하였다. 이들 영역은 시갈, 지각, 움직임 기능을 수행하며 theta2파가 주의, alpha1파가 각성 관련이다. 이상의 결과에서 두정엽의 우반구와 측두엽 및 후두엽의 좌반구영역의 theta1파, theta2파, alpha1파가 정신집중 작업 시 중요한 역할을 담당하는 것으로 나타났다.

• The Korean Journal of Nuclear Medicine
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• v.22 no.2
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• pp.147-156
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• 1988

알쯔하이머병 환자 11명, 우울증 환자 7명 그러고 정상 대조군 12명을 대상으로 $^{99m}Tc-HMPAO$ 뇌 SPECT를 이용하여 국소 뇌혈류 분포를 분석하여 다음과 같은 결과를 얻었다. 1) SPECT소견은 정상 대조군과 우울증군에서는 모두 정상이 있으나 알쯔하이머병군에서는 7명은 양측 측두엽 및 두정엽에, 3명은 편측 측두엽 및 두정엽에 그리고 1명은 전두엽에 뇌혈류 감소의 소견을 보였다. 2) 대뇌반구간 혈류분포의 변화를 비교하는 지수인 Cerebral asymmetry index는 정상 대조군에서 $0.08{\pm}0.03$, 알쯔하이머병군에서는 $0.11{\pm}0.04$ 그리고 우울증군에서는 $0.09{\pm}0.03$으로서 세 군간에 유의한 차이가 없었다. 3) 소뇌반구간 혈류분포의 변화를 비교하는 지수인 Percent index of cerebellar asymmetry는 정상 대조군에서 $0.4{\pm}0.7%$, 알쯔하이머병군에서 $-0.7{\pm}0.08%$ 그리고 우울증군에서 $-0.7{\pm}0.7%$로서 세군 간에 유의한 차이는 없었다. 4) 소뇌 계수치를 대조값으로 각 영역별 혈류분포의 변화정도를 비교하는 지수인 Region to cerebellum ratio는 우울증군에서는 정상 대조군과 유의한 차이를 보이지 않았으나 알쯔하이머병군에서는 양측 두정엽과 측두엽에서 유의한 감소를 보였다(p<0.05). 이상의 결과로 $^{99m}Tc-HMPAO$ 뇌 SPECT는 알쯔하이머병의 진단에 있어서 유용한 방법임을 알 수 있었다.

• Investigative Magnetic Resonance Imaging
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• v.9 no.1
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• pp.9-15
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• 2005

Purpose : This study attempted to investigate the effects of supply of highly concentrated $(30\%)$ oxygen on human ability of visuospatial cognition using time course data analysis of functional Magnetic Resonance Imaging (fMRI). Materials and Methods : To select an item set in the visuospatial performance test, two questionnaires with similar difficulty were developed through group testing. A group test was administered to 263 college students. Two types of questionnaire containing 20 questions were developed to measure the ability of visuospatial cognition. Eight college students (right-handed male, average age of 23.5 yrs) were examined for fMRI study. The experiment consisted of two runs of the visuospatial cognition testing, one with $21\%$ level of oxygen and the other with $30\%$ oxygen level. Each run consisted of 4 blocks, each containing control and visuospatial items. Functional brain images were taken from 37 MRI using the single-shot EPI method. Using the subtraction procedure, activated areas in the brain during visuospatial tasks were color-coded by t-score. To investigate the time course data in each activated area from brain images, 4 typical regions (cerebellum, occipital lobe, parietal lobe, and frontal lobe) were selected. Results : The average accuracy was $50.63{\pm}8.63$ and $62.50{\pm}9.64$ for $21\%\;and\;30\%$ oxygen respectively, and a statistically significant difference was found in the accuracy between the two types of oxygen (p<0.05). There were more activation areas observed at the cerebellum, occipital lobe, parietal lobe and frontal lobe with $30\%$ oxygen administration. The rate of increase in the cerebellum, occipital lobe and parietal lobe was $17\%$ and that of the frontal lobe, $50\%$. Especially, there were increase of intensity of BOLD signal at the parietal lobe with $30\%$ oxygen administration. The increase rate of the left parietal lobe was $1.4\%$ and that of the right parietal lobe, $1.7\%$. Conclusion : It is concluded that while performing visuospatial tasks, high concentrations of oxygen administration make oxygen administration sufficient, thus making neural network activate more, and the ability to perform visuospatial tasks increase.

• Proceedings of the Korean Society for Cognitive Science Conference
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• 2000.05a
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• pp.43-48
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• 2000

기억의 인출에 관여하는 전전두엽의 역할을 연구하기 위해 지각적 친숙성 정도가 다른 재인 조건을 비교하고, 이에 관여하는 뇌의 활성화 양상을 fMRI로 측정 분석하였다. 이를 위하여 동일조건; 그림으로 학습하고 동일한 내용의 다른 그림이 재인 단서로 주어지는 조건, 교차 조건; 단어로 학습하고 내용이 일치하는 그림이 재인 단서로 주어지는 조건이 비교되었다. 재인 수행(회상율, 정확도)은 동일 조건에서 가장 높앗으며 교차 조건에서 가장 저조하였다. 동일 조건 동안 양측 두정엽에서 가장 유의미한 활성화가 관찰되었으며, 상이 조건동안은 좌측 구조물들(Insular, 중 전전 두엽, hippocampal gyrus, 하두정엽 등)에서 활성화가 관찰되었다. 교차조건에서는 활성화가 좌우 시각 영역 및 두정엽의 연접부위 및 전두엽의 백질 부위(superior longitudinal fasciculus)에서 관찰되었다. 이는 그림의 인출과정에 우측 전두엽이 필수적인 것이 아니라, 인출에 수반되는 하위 정보처리 과정에 따라 다른 뇌 영역이 관여하고 있음을 시사한다. 예를 들어, 좌측 insular, 좌측 하 전전두엽에 의해 매개된 lexical processing이 상이한 그림의 재인과정에(상이조건), 시각피질과 좌측 전전두엽의 상호작용이 시각적으로 제시되었던 단어를 그림 단서로 인출하는 과정에(교차조건) 관여하고 있을 가능성을 시사하고 있다.

• The Korean Journal of Nuclear Medicine
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• v.29 no.3
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• pp.294-306
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• 1995

There has recently been increasing interest in the use of NMDA receptor antagonists as potential neuroprotective agents for the treatment of ischemic stroke. To evaluate the neuroprotective effect of the selective non-competitive NMDA receptor antagonist MK-801 in focal cerebral ischemia, local cerebral glucose utilization (ICGU) was examined in 15 neuroanatomically discrete regions of the conscious rat brain using the 2-deoxy-D[$^{14}C$] glucose quantitative autoradiographic technique 24 hr after left middle cerebral artery occlusion (MCAO). Animals received MK-801 (5 mg/kg i.v.) or saline vehicle before (20-30 min) or after (30 min) MCAO. Both pretreatment and posttreatment of MK-801 increased occluded/non-occluded ICGU ratio in 7 and 5 of the 15 regions measured, respectively (most notably in cortical structures). Following MK-801 pretreatment, there was evidence of widespread increases in ICGU not only in the non-occluded hemisphere (12 of the 15 areas studied) but also in the occluded hemisphere (13 of the 15 areas studied), while MK-801 postreatment did not significantly increase ICGU both in the normal and occluded hemispheres. These data indicate that MK-801 has a neuroprotective effect in focal cerebral ischemia and demonstrate that MK-801 provides widespread alterations of glucose utilization in conscious animals.

• Journal of Life Science
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• v.23 no.9
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• pp.1170-1176
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• 2013

Essential oils have been used to treat psychophysiological disorders, but their effects on human electroencephalographic (EEG) activity have not been thoroughly investigated. We evaluated the effects of essential oil of Zizyphus jujuba seeds, a Korean folk medicine known as San-Jo-In, on human EEG activity. For this purpose, essential oil was extracted from San-Jo-In by the supercritical carbon dioxide extraction method. The effect of its inhalation on EEG activity was evaluated by measuring the EEG power spectrum (25 indices) in 20 healthy participants. The results of the EEG power spectrum indicated that the values of the theta wave decreased significantly (p<0.05) in the left (from 17.277 to $13.854{\mu}V$) and right parietal (from 15.324 to $13.020{\mu}V$) regions compared to the other regions. During the inhalation of San-Jo-In oil, the EEG spectrum values of fast alpha, relative gamma, and spectral edge frequency increased 50% compared to those before inhalation. The values of the fast alpha wave increased significantly (p<0.05) in the left prefrontal (from 0.063 to $0.085{\mu}V$), right prefrontal (from 0.064 to $0.085{\mu}V$), and left frontal (from 0.073 to $0.100{\mu}V$) regions following inhalation of the San-Jo-In essential oil. The changes in the EEG activities following inhalation of San-Jo-In suggest that the oil can improve psychological well-being by increasing attention and relaxation.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.11
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• pp.206-216
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• 2013

The emotion plays a critical role in human's daily life including learning, action, decision and communication. In this paper, emotion discrimination classifier is designed to reduce system complexity through reduced selection of dominant features from biosignals. The photoplethysmography(PPG), skin temperature, skin conductance, fontal and parietal electroencephalography(EEG) signals were measured during 4 types of movie watching associated with the induction of neutral, sad, fear joy emotions. The genetic algorithm with support vector machine(SVM) based fitness function was designed to determine dominant features among 24 parameters extracted from measured biosignals. It shows maximum classification accuracy of 96.4%, which is 17% higher than that of SVM alone. The minimum error features selected are the mean and NN50 of heart rate variability from PPG signal, the mean of PPG induced pulse transit time, the mean of skin resistance, and ${\delta}$ and ${\beta}$ frequency band powers of parietal EEG. The combination of parietal EEG, PPG, and skin resistance is recommendable in high accuracy instrumentation, while the combinational use of PPG and skin conductance(79% accuracy) is affordable in simplified instrumentation.

• Science of Emotion and Sensibility
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• v.14 no.3
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• pp.403-414
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• 2011

The current study examined brain regions associated with aesthetic experience to fractal images using functional MRI. The aesthetic estimations of the images showed that there is a general consensus regarding the perception of beautiful images. Out of 270 fractal images, fifty images rated highest(beautiful images) and fifty images rated lowest(non-beautiful images) were selected and presented to the participants. The two conditions were presented using the block design. Frontal lobes, cingulate gyri, and insula, the areas related to the cognitive and emotional processing in aesthetic experience, were activated when beautiful images were presented. In contrast, the middle occipital gyri and precuneus, the areas associated with experience of negative emotions, were activated when non-beautiful images were presented. The conjunction analysis showed activations in temporal areas in response to beautiful images and activations in parietal areas in response to non-beautiful images. These results indicate that beautiful images elicit semantic interpretations whereas non-beautiful images facilitate abstract processes.