• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2006년도 제33회 추계학술대회 발표논문집
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• pp.149-149
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• 2006

• 대한의용생체공학회:의공학회지
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• 제26권4호
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• pp.223-230
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• 2005

This paper presents a new approach to investigate spatial correlation between independent components of brain alpha activity in functional magnetic resonance imaging (fMRI) and electroencephalography (EEG). To avoid potential problems of simultaneous fMRI and EEG acquisitions in imaging pure alpha activity, data from each modality were acquired separately under a 'three conditions' setup where one of the conditions involved closing eyes and relaxing, thus making it conducive to generation of alpha activity. The other two conditions -- eyes open in a lighted room or engaged in a mental arithmetic task, were designed to attenuate alpha activity. Using a Mixture Density Independent Component Analysis (MD-ICA) that incorporates flexible non-linearity functions into the conventional ICA framework, we could identify the spatiotemporal components of fMRI activations and EEG activities associated with the alpha rhythm. Then, the sources of the individual EEG alpha activity component were localized by a Maximum Entropy (ME) method that is specially designed to find the most probable dipole distribution minimizing the localization error in sense of LMSE. The resulting active dipoles were spatially transformed to 3D MRls of the subject and compared to fMRI alpha activity maps. A good spatial correlation was found in the spatial distribution of alpha sources derived independently from fMRI and EEG, suggesting the proposed method can localize the cortical areas responsible for generating alpha activity successfully in either fMRI or EEG. Finally a functional connectivity analysis was applied to show that alpha activity sources of both modalities were also functionally connected to each other, implying that they are involved in performing a common function: 'the generation of alpha rhythms'.

• 한국콘텐츠학회논문지
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• 제14권12호
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• pp.854-862
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• 2014

주의력결핍 과잉행동장애(ADHD) 학생의 지적결함, 학습 문제 및 저조한 학업 성취는 이들이 정상 학생에 비해 현저하게 낮은 지능을 가졌기 보다는 주의를 집중하지 못하는 특성 때문이다. 따라서 본 연구에서는 ADHD 학생들과 정상군 학생들의 뇌기능영상을 비교 분석함으로써 ADHD 학생들의 뇌기능 차이와 작업기억 과제 시 나타나는 뇌의 활성영역의 차이를 보고자 하였다. 인천지역 초등학교 학생 26명을 대상으로 뇌기능영상과 임상설문검사를 실시하였으며, 뇌기능영상의 자극은 작업기억으로 하였다. 분석에는 통계적 파라미터 지도작성법과 사회과학통계패키지를 이용하여 단일표본 t 검정, 두 표본 t 검정, 다중 회기 분석등으로 분석 하였으며, 통계적 유의수준은 p<0.05에서 나타내었다. 그 결과 ADHD 학생들의 전두 피질, 두정엽 피질, 시상, 미상핵 등 많은 부분에서 불균형적인 발달을 볼 수 있었다. 또한, 작업기억 과제 수행의 어려움을 느낄수록 일부 안와 전두 피질, 해마가 활성화되었다. 보다 많은 ADHD 학생들의 대상자가 확보되어 ADHD 유형별 연구가 필요하며, 뇌기능영상에서 보다 많은 자극으로 실험한다면 ADHD 학생들의 전반적인 뇌기능평가에 유용할 것으로 판단된다.

• 대한자기공명의과학회:학술대회논문집
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• 대한자기공명의과학회 2001년도 제6차 학술대회 초록집
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• pp.104-104
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• 2001

Purpose： In this study, we investigated the possible motor pathways of hemiplegic stroke patients usin combined TMS and BOLD fMRI approach and evaluated the correlation between TMS a fMRI methods. Method： Four subjects, who demonstrated left hemiplegia after stroke, are included. TMS was performed using a Dantec Mag2 stimulator (Dantec Company, USA) in single puls mode with figure eight-shaped coil. Following TMS localization, The BOLD T2＊-weight images were acquired with echo planar imaging sequence (TR = 1.2 sec, TE = 60 msec, and flip angle = 90). Motor activation was studied by means of a repetitive fing flexion-extension task. The stimulation protocol comprised 10 cycles of alternating activati and rest (10 images per cycle). Total 60 cycles were performed and each cycle take abou 1.5 sec. The resulting images were then analyzed with STIMULATE (CMRR, U, o Minnesota) to generate functional maps using a student t-test (p < 0.0005) and cluste analysis.

• The Journal of Korean Physical Therapy
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• 제15권3호
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• pp.295-345
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• 2003

This study investigated activation of cerebral cortex in patients with hemiplegia that was caused by neural damage. Key-point control movement therapy of Bobath was performed for 9 weeks in 3 subjects with hemiplegia and fMRI was used to compare and analyze activated degree of cerebral cortex in these subjects. fMRI was conducted using the blood oxygen level-dependent(BOLD) technique at 3.0T MR scanner with a standard head coil. The motor activation task consisted of finger flexion-extension exercise in six cycles(one half-cycles = 8 scans = $3\;sec{\times}\;8\;=\;24\;sec$). Subjects performed this task according to visual stimulus that sign of right hand or left hand twinkled(500ms on, 500ms off). After mapping activation of cerebral motor cortex on hand motor function, below results were obtained. 1. Activation decreased in primary motor area, whereas it increased in supplementary motor area and visual association area(p<.001). 2. Activation was observed in bilateral medial frontal gyrus, middle frontal gyrus of left cerebrum, inferior frontal gyrus, inter-hemispheric, fusiform gyrus of right cerebrum, superior parietal lobule of parietal lobe and precuneus in subjedt 1, parahippocampal gyrus of limbic lobe and cingulate gyrus in subject 2, and inferior frontal gyrus of right frontal lobe, middle frontal gyrus, and inferior parietal lobule of left cerebrum in subject 3 (p<.001). 3. Activation cluster extended in declive of right cellebellum posterior lobe in subject 1, culmen of anterior lobe and declive of posterior lobe in subject 2, and dentate gyrus of anterior lobe, culmen and tuber of posterior lobe in subject 3 (p<.001). In conclusion, these data showed that Key-point control movement therapy of Bobath after stroke affect cerebral cortex activation by increasing efficiency of cortical networks. Therefore mapping of brain neural network activation is useful for plasticity and reorganization of cerebral cortex and cortico-spinal tract of motor recovery mechanisms after stroke.

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2004년도 제29회 추계학술대회 발표논문집
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• pp.49-52
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• 2004

A few studies have shown that the function of fusiform face area is selectively involved in the perception of faces including a race difference. We investigated the neural substrates of the face-selective region called fusiform face area In the ventral occipital-temporal cortex and same-race memory superiority In the fusiform face area by the event-related fMRI. In our fMRI study, twelve healthy subjects (Oriental-Korean) performed the implicit distinction of the race while they consciously made familiar-judgments, regardless of whether they considered a face as Oriental-Korean or European-American. In the race distinction as an implicit task, the fusiform face areas (FFA) and the right parahippocampal gyrus had a greater response to the presentation of Oriental-Korean than European-American faces, but in the consciously race distinction between Oriental-Korean and European-American faces, any significant difference in the FFA was not observed. These results suggest that different activation in the fusiform regions and right parahippocampal gyrus resulting from same-race memory superiority could be implicitly taken place by the physiological processes of face recognition.

• 스마트미디어저널
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• 제10권2호
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• pp.55-60
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• 2021

뇌의 신호는 관측 대상의 상태 및 관측 위치에 따라 신호가 다양하게 변화하기 때문에 연구하기 쉽지 않다. 본 연구에서는 사람이 수면 전에 수행한 일이 수면 중에 미치는 영향을 분석하는 실험을 수행한다. 이를 위해서, EEG와 fMRI 장비로 피실험자의 뇌의 신호를 획득하고 분석한다. 시간에 따라 변화하는 뇌 신호를 분석하기 위해서 conditional random fields를 이용한다. 피실험자는 수면 전에 미로 찾기 게임과 얼굴 찾기 게임을 수행하며, 이 중 하나의 게임만 성공할 수 있다. 주어진 게임에 성공하면 이에 대한 보상을 받는다. 그리고 피실험자는 EEG와 fMRI 장비에서 수면을 취한다. 수면 중 깊은 잠으로 분류되는 N3상태에 도달하면, 얼굴 찾기를 성공한 그룹에서는 수면 전에 얼굴 찾기를 수행하는 동안 활성화 됐던 뇌의 영역이 미로 찾기를 성공한 그룹보다 상대적으로 유의미하게 활성화되는 것을 알 수가 있었다. 반대로 미로 찾기 성공 그룹에서도 같은 현상이 발생하였다.

• 한국감성과학회:학술대회논문집
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• 한국감성과학회 2009년도 춘계학술대회
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• pp.101-104
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• 2009

This study investigated compensatory mechanisms in the brain during a verbal working memory task among people with Alcohol Use Disorders (AUD). A total of 21 college male students participated in the study: eleven AUD participants and 10 normal controls. Study participants were asked to complete the Korean version of the Wechsler Adult Intelligence Scale-III (K-WAIS-III) prior to the fMRI experiment. Verbal 0-back and 2-back tasks were used to assess brain activities of the participants' verbal working memory. Brain scanning was performed on Siemens SONATA 1.5T Scanner while participants were performing the 0-back and 2-back tasks. Within the AUD group, participants with greater dependency to alcohol (based on DSM-IV criteria) in the past 1 year showed lower mean score on the 'Similarities' of the K-WAIS-III (r=-0.63, p<0.05, N=11). The more participants experienced alcohol withdrawal symptoms in the past 1 year, the lower the score they received on the K-WAIS-III 'Picture Arrangement' (r=-0.69, p<0.05, n=11). The fMRI regression results showed that individuals who present greater degree of alcohol dependency symptoms are likely to show greater brain activation in the bilateral middle frontal gyri (BA 9) during the verbal working memory task. The degree of alcohol withdrawal symptoms were associated with increased brain activation in the left superior and middle frontal gyri (BA8), left precentral gyrus (BA 6), and left inferior parietal lobule (BA 40). The study findings showed that the degree of alcohol abuse/dependence and withdrawal symptoms were associated with decreased cognitive function and increased activations in brain regions particularly important for abstract reasoning (BA 9), central executive (BA 9), or spatial storage (BA 40) during a working memory task. Therefore, these results could support previous studies suggesting that the neural system of people with ADD may adopt a brain compensatory mechanism to maintain normal level of cognitive functions.

• 대한의용생체공학회:의공학회지
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• 제29권4호
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• pp.272-277
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• 2008

Functional MRI technique was used in this study for examining the language switching mechanisms between the first language (L1) and the second language (L2). Language switching mechanism is regarded as a complex task that involves an interaction between L1 and L2. The aim of study is to find out the brain activation patterns during the phonological process of reading real English words and English words written in Korean characters in a bilingual person. Korean-English bilingual subjects were examined while they covertly read four types of words native Korean words, Korean words of a foreign origin, English words written in Korean characters, and English words. The fMRI results reveal that the left hemispheric language-related regions at the brain, such as the left inferior frontal, superior temporal, and parietal cortices, have a greater response to the presentation of English words written in Korean characters than for the other types of words, in addition, a slight difference was observed in the occipital-temporal lobe. These results suggest that a change in the brain circuitry underlying the relational processes of language switching is mainly associated with general executive processing system in the left prefrontal cortex rather than with a similarity-based processing system in the occipital-temporal lobes.

• Investigative Magnetic Resonance Imaging
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• 제12권1호
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• pp.33-39
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• 2008

목적: 특정 임무 부여시 특정 뇌피질의 대사물질의 변화를 자기공명 분광법으로 관찰할 수 있는지에 대해서는 논란이 있다. 이 연구의 목적은 실시간 기능적 자기공명영상 유도하의 기능적 자기공명분광법으로 손운동 수행중 운동피질의 젖산의 변화를 관찰하는 것이다. 대상 및 방법: 7명의 지원자(23-28세)를 대상으로 1.5 테슬라 자기공명영상 기계를 이용하여 우측 손을 쥐었다 폈다 반복하는 운동을 하면서 실시간 기능적 자기공명영상을 시행하여 뇌의 활성 영역을 확인한 후, 뇌의 활성 피질 부위에서 1)운동 전, 2) 운동 중, 3)운동 후에 단체적 자기공명분광법을 시행하였다. 연속적인 3회의 분광스펙스럼에서 운동에 의한 젖산의 변화를 비교 관찰하였으며, 이들 분광스펙트럼으로부터 Cho/Cr 비, NAA/Cr 비, Lac/Cr 비를 측정하였다. 결과: 실시간 기능적 자기공명영상에서 확인된 뇌의 활성 영역부위의 운동중 자기공명 분광에서 1.33 ppm 부위에 젖산 피크들이 현저하게 관찰되었으며, 운동후 스펙트럼에서 젖산 피크는 소실되어 운동전 상태로 회복되었다. 운동전, 운동중, 운동후에 Cho/Cr 비는 각각 0.81, 0.76, 0.77이고, NAA/Cr 비는 1.68, 1.65, 1.72이며, Lac/Cr 비는 0.28, 0.41, 0.30 이였으며, 운동중에 젖산은 46% 증가하였다. 결론: 저자들은 실시간 기능적 자기공명영상에서 확인된 뇌의 활성 영역부위에서 운동중 자기공명 분광법으로 현저한 젖산 피크들을 관찰하였으며, 이 기능적 자기공명분광법은 활성 뇌영역의 대사물질 변화를 실시간으로 관찰하는 수단으로 이용될 수 있을 것으로 생각된다.