• Proceedings of the KSMRM Conference
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• 2003.10a
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• pp.82-82
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• 2003

목적： 인간은 시각적 자극에 뇌가 반응함으로써 대상을 파악한다. 그리고 대상의 종류에 따라 뇌가 시각적인 정보를 판단하는 영역은 서로 다를 수 있다는 것을 예상할 수 있다. 본 연구에서는 시각적 자극의 대상을 크게 인간의 안면과 사물로 나누고 그 대상에 따라 인지하는 뇌의 영역을 확인하고자 한다.

• Progress in Medical Physics
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• v.15 no.3
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• pp.128-133
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• 2004

The fMRI response of the somatosensory cortex was investigated with vibrotactile stimulation. Three different frequencies of 8, 15, or 25 Hz were applied in order to mainly focus on the hemodynamic response of Meissner corpuscles sensitive to frequencies of 5-40 Hz. A closed-system, pneumatically-driven, rubber diaphragm was fabricated that overcame many of the limitations of existing vibrotactile devices and produced robust sensory cortex activation in an fMRI experiment. Increasing frequency vs. activation area was analyzed in terms of signal percent change and number of pixels. Our preliminary results indicated that the distribution of the signal percentage change widened and more activated pixels were obtained with higher frequencies.

• Progress in Medical Physics
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• v.17 no.3
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• pp.159-166
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• 2006

The nonlinearity of hemodynamic response in the somatosensory cortex was investigated with vibrotactile stimulation. The stimuli consisted of a train of 25 Hz, each tasting five different duration periods, 2 s, 4 s, 8 s 12 s, or 16 s with 20 sec periods of no vibration in a pseudo-random order. In order to understand the linearity on the change of stimulus duration for somatosensory cortex, two different tests- checking the linearity of system and finding the impulse response function from gamma-variate function were applied to analyze the hemodynamic response functions. They have produced nearly same results. The BOLD response in the somatosensory cortex Is nonlinear for stimuli of less than 8 seconds, but nearly linear for stimuli greater than 8 seconds. The amplitude, area, TTP, and FWHM as functions of the stimulus duration were calculated and showed a significant downward trend with Increasing stimulus duration for the amplitude and the area. It supports the ranges of nonlinearity are less than 8 seconds.

• Korean Journal of Cognitive Science
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• v.13 no.1
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• pp.23-40
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• 2002

This study is to examine brain regions that are involved in picture encoding in normal adults using fMRI methods. In Scan 1, the picture encoding was studied during a semantic categorization task in comparison with word. In Scan 2 task type effects were studied both during a picture naming task and during a semantic categorization task with pictures. Subjects were asked to make decision either by pressing a mouse button (Scan 1) or by responding subvocally (naming or saying yes/no) (Scan 2). Regardless of stimulus type, left prefrontal, bilateral occipital, and parietal activations were observed during semantic processing in comparison with fixation baseline. Processing of word stimulus relative to picture resulted in activations in prefrontal and parieto-temporal regions in the left side while that of picture stimulus relative to word resultd in activations in bilateral extrastriatal visual cortices and parahippocampal regions. In spite of the same task demands, stimulus-specific information processings were involved and mediated by different neural substrates; the word encoding was associated with more semantic/lexical processings than pictures and the picture processing associated with more perceptual and novelty related information processings than word. Activations of dorsal part of inferior prefrontal region, i.e., Broca's areas were found both during the picture naming and during the semantic tasks subvocally performed Especially, during the picture naming task, greater occipital activations were found bilaterally relative to the semantic categorization task. indicating a possibility that greater and higher visual processing was involved in retrieving the name referred by picture stimuli.

• Proceedings of the Korean Society for Cognitive Science Conference
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• 2006.06a
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• pp.47-51
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• 2006

본 실험은 한국어 심성어휘집의 표상 정보가 음운정보로 이루어져 있는지, 철자정보로 이루어져 있는지 알아보기 위해 실시되었다. 실험자극은 한국어의 2음절 단어 중 음운변화(자음동화)를 겪는 단어(예: 국민)를 사용하였으며, 각 조건은 철자이웃이 크며 음운 이웃이 큰 단어 조건(O+P+), 철자이웃이 크고 음운이웃은 작은 단어 조건(O+P-), 철자이웃은 작고 음운이웃이 큰 단어 조건(O-P+), 철자이웃과 음운이웃 모두가 작은 조건(O-P-)이었다 실험 1에서 어휘판단 과제를 실시한 결과, 음운이웃 크기와 철자이웃 크기간의 상호작용이 나타났다. 실험2는 동일한 실험자극을 사용한 fMRI 연구를 수행하였다. 실험2 결과 음운처리에 관련된 뇌영역의 활성화가 나타났다. 본 연구결과는 한국어의 경우 심성어휘집이 음운정보로 이루어져 있음을 시사한다.

• Proceedings of the Korean Society for Cognitive Science Conference
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• 2002.05a
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• pp.231-235
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• 2002

본 논문에서는 전문 안무가와 일반인들을 대상으로, 현대적 스타일의 독무와 임의적으로 움직이는 육면체를 제시할 때의 두뇌 활동 양상을 fMRI를 통하여 알아보았다. 피험자들은 총 8명으로 구성되었으며, 4명은 안무 전문가들, 4명은 동일한 연령대의 일반인들이었다. 피험자들은 시각 자극으로 제시되는 춤동작과 다양하게 변화하는 단순한 육면체의 움직임을 아무런 반응 없이 보는 과제를 수행하였다. 두 피험자 그룹 모두에서 육면체의 움직임보다 무용을 응시할 때 occipital cortex에서 더 큰 활성화를 보였고, 특히 좌측 STS와 angular gyrus사이의 경계선 영역, 그리고 좌측 fusiform gyrus에서는 안무가들이 무용을 볼 때 일반인들보다 더 높은 활성화를 나타내었다. STS/angular gyrus와 fusiform gyrus가 시각 자극의 의미 표상을 이해하는데 관련이 있고, angular gyrus가 사전적 의미 해석에 있어 중계적 역할을 하는 곳이며, fusiform gyrus는 사물을 지각하는데 있어서 보조 역할을 맡고 있다는 논의를 바탕으로, 무용가들은 그들이 지니고 있는 안무에 대한 전문적인 소견과 지식을 이용하여 몸의 움직임을 분석할 수 있고, 또 그것에서부터 어떠한 상징적인 의미까지 끌어내어 결과적으로 의미 추출의 과정에서 두뇌의 semantic network를 활성화시킨다고 볼 수 있다.

• The Journal of the Korea Contents Association
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• v.14 no.12
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• pp.854-862
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• 2014

Attention deficit hyperactivity disorder (ADHD) students' intellctual defects, learning problems, and poor academic achievements seem to be due to significantly lower intelligence compared to the normal students, but rather the characteristic of inability to pay attention at a given time can be seen as the more attributing reason. In this study, a comparison between the ADHD students and the normal students will be performed using a fMRI analysis in order to differentiate the brain function between the two groups during a working memory task performance and to assess the difference in the activated regions of the brain. Clinical survey examinations and fMRI measurements were performed for a group of 26 elementary students from the Incheon area. The stimulus of fMRI was a working memory. Cartography statistically analyzed parameters and the Statistical Package of Social Sciences using single-sample t-test, two-sample t-test, were analyzed by multiple regression analysis, the statistical significance level was p<0.05 in, respectively. The disproportionate developments could be seen in the ADHD students group such as the frontal cortex, parietal cortex, thalamus, and caudate nucleus, among others. In addition, as some students felt the increase in the difficulty of working memory task performance, the orbitofrontal cortex and the hippocampus were activated, which seems to be the result of an effort for looking for an answer. More types of ADHD students needs to be secured as research subjects, and more stimulations for fMRI experiments should be considered as it would be useful in the overall evaluation of brain function.

• Science of Emotion and Sensibility
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• v.14 no.2
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• pp.235-244
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• 2011

The purpose of this study is to investigate whether the appropriateness of gustatory features in product design affect product evaluation and accompanied response by using functional magnetic resonance imaging(fMRI). Through the pilot survey, we categorized the product designs into two groups based on the level of the appropriateness. The total of 40 product designs were selected as the experimental stimuli. 15 right-handed participants(mean age = 23.33, SD = 1.7) were scanned with 3T MRI machine(ISOL Tech, Oxford OR63). The experimental stimuli were passively presented inside the scanner. In post scanning session, participants were asked to measure their preference and buying intention to the product designs. The results show that both the preference and buying intention were significantly higher for the high appropriateness condition compared to those of low appropriateness designs. Caudate nucleus and putamen, areas related to the positive reward such as monetary acquisition showed greater activation in response to the designs of high appropriateness condition, compared to the low appropriateness designs.

• Korean Journal of Acupuncture
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• v.21 no.2
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• pp.29-46
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• 2004

Objectives and Methods : This study was performed to investigate the effect of electro -acupuncture at four gates(bilateral LR3 and LI4) on brain activity in normal subjects using fMRI. Results and Conclusions : 1. fMRI signal increase by electro-acupuncture at Lt. LR3 was observed in Rt. Middle frontal gyrus in group average as well as more than half of the subjects. 2. fMRI signal decreases by electro-acupuncture at Lt. LR3 were observed in Rt. Superior frontal gyrus, Rt. Middle temporal gyrus, Rt. Cingulate gyrus in group average as well as more than half of the subjects. 3. fMRI signal increases by electro-acupuncture at Lt. LI4 were observed in Lt. Superior frontal gyrus, Lt. Middle frontal gyrus, Lt. Inf. Semi-Lunar Lobule(cerebellum), Rt. Middle frontal gyrus, Rt. Cingulate gyrus in group average as well as more than half of the subjects. 4. fMRI signal decreases by electro-acupuncture at Lt. LI4 were observed in Lt. Middle frontal gyrus, Lt. Inferior frontal gyrus, Lt. Precentral gyrus and Rt. Middle frontal gyrus, Rt. Middle temporal gyrus, Rt. Precuneus, Rt. Inferior frontal gyrus, Rt. Postcentral gyrus in group average as well as more than half of the subjects. 5. fMRI signal increase by electro-acupuncture at Lt. LR3 and Lt. LI4 in group average as well as more than half of the subjects was not observed. 6. fMRI signal decreases by electro-acupuncture at Lt. LR3 and Lt. LI4 were observed in Lt. culmen(cerebellum), Lt. Cingulate gyrus와 Rt. Middle frontal gyrus, Rt. Cingulate gyrus, Rt. Inferior frontal gyrus in group average as well as more than half of the subjects. 7. fMRI signal increases by electro-acupuncture at four gates (bilateral LR3 and LI4) were observed in Lt. Middle temporal gyrus and Lt. Postcentral gyrus in group average as well as more than half of the subjects. 8. fMRI signal decrease by electro-acupuncture at four gates (bilateral LR3 and LI4) were observed in Lt. Middle frontal gyrus, Lt. Precentral gyrus, Lt. Inferior frontal gyrus, Lt. Middle temporal gyrus, Lt. Frontal sub-gyral and Rt. Tuber(cerebellum) in group average as well as more than half of the subjects.

• Investigative Magnetic Resonance Imaging
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• v.14 no.2
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• pp.115-120
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• 2010

Purpose : To separate and evaluate the low frequency spontaneous fluctuation BOLD signals from the functional magnetic resonance imaging data using sensorimotor active task. Materials and Methods : Twenty female archery players and twenty three control subjects were included in this study. Finger-tapping task consisted of three cycles of right finger tapping, with a subsequent 30 second rest. Blood oxygenation level-dependent (BOLD) data were collected using $T2^*$-weighted echo planar imaging at a 3.0 T scanner. A 3-D FSPGR T1-weighted images were used for structural reference. Image processing and statistical analyses were performed using SPM5 for active finger-tapping task and GIFT program was used for statistical analyses of low frequency spontaneous fluctuation BOLD signal. Results : Both groups showed the activation in the left primary motor cortex and supplemental motor area and in the right cerebellum for right finger-tapping task. ICA analysis using GIFT revealed independent components corresponding to contralateral and ipsilateral sensorimotor network and cognitive-related neural network. Conclusion : The current study demonstrated that the low frequency spontaneous fluctuation BOLD signals can be separated from the fMRI data using finger tapping paradigm. Also, it was found that these independent components correspond to spontaneous and coherent neural activity in the primary sensorimotor network and in the motor-cognitive network.