Human Brain Mapping of Visual Script Familiarity between Phonological and Logographic Language: 3 T Functional MRI Study

Kim, Nambeom,Kim, Jongho,Kang, Chang-Ki,Park, Chan-A,Lim, Mi-Ra,Kim, Young-Bo,Bak, Byung-Gee Hindawi 2017 BioMed research international Vol.2017 No.-

<P>Neurolinguistic circuitry for two different scripts of language, such as phonological scripts (PhonoS) versus logographic scripts (LogoS) (e.g., English versus Chinese, resp.), recruits segregated neural pathways according to orthographic regularity (OrthoR). The purpose of this study was to identify the effect of VSF for cortical representation according to different OrthoR to represent Hangul versus Hanja as PhonoS versus LogoS, respectively. A total of 24 right-handed, native Korean undergraduate students with the first language of PhonoS and the second language of LogoS were divided into high- or low-competent groups for L2 of LogoS. The implicit word reading task was performed using Hanja and Hangul scripts during functional magnetic resonance imaging (fMRI) acquisition. Fluctuations of fMRI BOLD signal demonstrated that the LogoS was associated with the ventral pathway, whereas PhonoS was associated with the dorsal pathway. By interaction analysis, compared with high-competent group, low-competent group showed significantly greater activation for Hanja than for Hangul reading in the right superior parietal lobule area and the left supplementary motor area, which might be due to neural efficiency such as attention and cognition rather than core neurolinguistic neural demand like OrthoR processing.</P>

Language Switching Between Hanja and Hangeul : An fMRI Experiment

( Nambeom Kim ),( Kyung Jin Lee ),( Chang Ki Kang ),( Young Bo Kim ),( Yeong Bae Lee ) 한국감성과학회 2016 춘계학술대회 Vol.2016 No.-

The Influence of Life Stress and Sleep Disturbance on White Matter Integrity

Kim Minjeong,Lee Jiye,Kim Nambeom,Hwang Yunjee,Lee Kyung Hwa,Lee Jooyoung,Lee Yu Jin,Kim Seog Ju 대한신경정신의학회 2023 PSYCHIATRY INVESTIGATION Vol.20 No.5

Objective This study investigated whether sleep and stress mutually interact to induce changes in white matter integrity.Methods Diffusion tensor imaging (DTI) was conducted on 36 participants (male=22, female=14; mean age=38.33±12.78 years). Participants were divided into three groups depending on their sleep quality and stress levels: poor sleepers with stress, poor sleepers without stress, and good sleepers. Sleep quality and stress level were evaluated using the Pittsburgh Sleep Quality Index and the Life Experiences Survey, respectively. Fractional anisotropy (FA) values were calculated employing DTI tractography.Results After controlling for age and sex, poor sleepers with stress exhibited a lower FA of the left inferior cerebellar peduncle (ICP) than did poor sleepers without stress (t=2.81, p=0.02). Poor sleepers without stress showed a higher FA of the right middle longitudinal fasciculus (MdLF) than did good sleepers (t=3.35, p=0.006).Conclusion The current study reports the effects of sleep, stress, and their interaction on the white matter integrities of the ICP and MdLF. ICP change seems to be associated with sleep disturbances related to stress, while MdLF change would be associated with sleep disturbances unrelated to stress.

The Cortical Representation of Visual Script Familiarity: fMRI Experiment

( Nambeom Kim ),( Yeong Bae Lee ),( Young Bo Kim ),( Chang Ki Kang ) 한국감성과학회 2015 추계학술대회 Vol.2015 No.-

It has been a great interest of the extent or degree to which visual script familiarity affects cortical representation. Because an alienation of the Hanja writing system was caused by the Hangul-only policy promoted by the South Korean government in the mid-1970s, Korean younger generation has dichotomized by Hanja familiarity. Therefore, the purpose of this study was to examine the script familiarity of Hanja and then identify the cortical foci related to the script familiarity. In this study, we recruited low familiarity group (LF) and high familiarity group (HF) by their Hanja competency, who performed fMRI reading experiment with two-letter Hanja scripts and two-letter Hangul scripts. We hypothesized that cortical representation between LF and HF during Hanja reading compared to Hangul reading would show a different pattern reflecting the script familiarity. fMRI results indicated that the LF group showed greater involvement of the right hemisphere including the right superior parietal lobule and supplementary motor area, whereas the HF group showed greater activation bilateral caudate nuclei. In conclusion, less familiar script showed greater right hemisphere lateralization during script processing, which is presumably engaged in increased general cognitive demand due to neural efficiency whereas higher familiar script was shown to engage in that of controlling language, presumably literacy skills. Acknowledgement This work was supported by the Gachon University research fund (GCU-2015-5030).

Effect of Lifetime Cognitive Reserve on Functional Connectivity in the Default Mode Network at the Predementia Stage

Soo Kyun Woo,Jae Myeong Kang,Nambeom Kim,Sook Young Lee,Sangsoon Kim,Da Jeong Kim,Chang-Ki Kang,Jun-Young Lee,Seong-Jin Cho 대한노인정신의학회 2021 노인정신의학 Vol.25 No.2

Objective: Cognitive reserve (CR) protects against cognitive decline by utilizing functional connectivity (FC) in the brain, such as the default mode network (DMN). We studied whether CR in individuals with predementia would correlate with better cognition and increased DMN FC in the resting brain. Methods: Fifty-four participants with subjective cognitive decline or mild cognitive impairment completed the Cognitive Reserve Index (CRI) questionnaire, and underwent a comprehensive neuropsychological test battery and resting state functional magnetic resonance imaging. Correlation and regression analyses for clinical variables and seed-to-voxel analyses of CR-related FC in the DMN were conducted. Results: CRI total (β=0.42, p=0.001), education (β=0.39, p=0.001), and leisure time (β=0.33, p=0.009) predicted the Mini- Mental State Examination. The CRI education predicted verbal memory recall (β=0.32, p=0.017), confrontational naming (β=0.57, p<0.001), and phonemic fluency (β=0.43, p=0.004). In the DMN in the resting brain, the CRI total correlated with increased FC, based on the posterior cingulate to both lateral parietal cortices. Conclusion: In individuals with predementia, comprehensive CR correlated with an enhanced network in the DMN in the resting state. These results may support the neural correlate of CR during the initial stage of cognitive decline.

주성분분석을 이용한 C[11]-PIB imaging 영상분석

김남범,신귀순,안성민,Kim, Nambeom,Shin, Gwi Soon,Ahn, Sung Min 대한핵의학기술학회 2015 핵의학 기술 Vol.19 No.1

주성분분석(Principal component analysis, PCA)은 고차원 변수들 사이의 복잡한 상관성 구조를 더 낮은 차원으로 단순화하여 상관성의 구조를 쉽게 설명하기 위한 다변량분석기법으로 뇌영상 분석에서 자주 사용되는 방법이다. 주성분분석의 기본개념은 서로 직교하는 변수들의 선형결합을 통해서 원래의 뇌영상 자료가 가지고 있는 전체정보를 최대한 설명할 수 있는 서로 독립적인 새로운 변수들을 유도하는 것이다. 뇌영상분석에서 주성분분석의 효율성과 유용성을 알아보기 위해서 C[11]-PIB 영상을 이용하여 분석하였다. 대상 및 방법으로는 평균나이가 같은 9명의 정상인, 10명의 알츠하이머/경도인지장애환자들의 C[11]-PIB 영상을 이용하였다. PET-CT 장비로는 Biograph 6 Hi-Rez (Siemens-CTI, Knoxville, TN)를 영상을 획득하였고 9.6 MBq/kg C[11]-PIB를 정맥주사 한 후 40분 후에 20분 동안 3D acquisition mode로 방출영상을 얻었다. Attenuation map은 X-ray CT scan을 이용하여 재구성하였다(130 kVp, 240 mA). PIB template을 만들기 위해서 정상인에서 3T MRI T1-weighted 영상을 동시에 얻었다. 주성분분석을 위한전처리과정으로서 공간정규화 및 공간편평화를 SPM8을 이용하여 실시하였고 주성분분석은 Matlab2012b를 이용하여 분석하다. 결과는 주성분분석을 통해서 서로 독립적인 주성분영상들을 얻을 수 있었다. 주성분분석을 통해서 얻어진주성분영상은 C[11]-PIB brain PET 영상의 패턴을 몇 개의 주성분으로 단순화 할 수 있었으며 주로는 neocortex를 변동 나타내는 영상, white matter의 변동을 나타내는 영상 그리고 pons등 deep brain의 변동을 나타내는 영상 등으로 단순화되었다. 결론으로는 주성분분석은 C[11]-PIB brain 영상을 단순화하여 영상의 패턴을 해석하는데 매우 유용하였다. 이러한 주성분분석은C[11]-PIB영상 분석뿐만 아니라 뇌의 포도당 대사를 측정하는 FDG-PET 또는 뇌기능영상등의 다변량분석 방법으로서 그 적용범위가 클 것으로 기대된다. Purpose Principal component analysis (PCA) is a method often used in the neuroimagre analysis as a multivariate analysis technique for describing the structure of high dimensional correlation as the structure of lower dimensional space. PCA is a statistical procedure that uses an orthogonal transformation to convert a set of observations of correlated variables into a set of values of linearly independent variables called principal components. In this study, in order to investigate the usefulness of PCA in the brain PET image analysis, we tried to analyze C[11]-PIB PET image as a representative case. Materials and Methods Nineteen subjects were included in this study (normal = 9, AD/MCI = 10). For C[11]-PIB, PET scan were acquired for 20 min starting 40 min after intravenous injection of 9.6 MBq/kg C[11]-PIB. All emission recordings were acquired with the Biograph 6 Hi-Rez (Siemens-CTI, Knoxville, TN) in three-dimensional acquisition mode. Transmission map for attenuation-correction was acquired using the CT emission scans (130 kVp, 240 mA). Standardized uptake values (SUVs) of C[11]-PIB calculated from PET/CT. In normal subjects, 3T MRI T1-weighted images were obtained to create a C[11]-PIB template. Spatial normalization and smoothing were conducted as a pre-processing for PCA using SPM8 and PCA was conducted using Matlab2012b. Results Through the PCA, we obtained linearly uncorrelated independent principal component images. Principal component images obtained through the PCA can simplify the variation of whole C[11]-PIB images into several principal components including the variation of neocortex and white matter and the variation of deep brain structure such as pons. Conclusion PCA is useful to analyze and extract the main pattern of C[11]-PIB image. PCA, as a method of multivariate analysis, might be useful for pattern recognition of neuroimages such as FDG-PET or fMRI as well as C[11]-PIB image.

The influence of long time 4G hypergravity in vestibular system

Gyu cheol HAN(한규철),Mi joo KIM,Yu Jin MIN,Dongju LEE,Nambeom KIM 한국항공우주의학협회 2016 항공우주의학 학술대회 Vol.2016 No.5

Intermixed structure of voxels with different hemispheric characteristics in the fusiform face area

Choi, Uk-Su,Sung, Yul-Wan,Choi, Sang-Han,Kim, Nambeom,Kim, Young-Bo,Cho, Zang-Hee,Ogawa, Seiji Lippincott Williams Wilkins, Inc. 2013 NEUROREPORT - Vol.24 No.2

The fusiform face area, a high-level visual area, is pivotal in processing facial information. This area receives inputs from the left and right visual fields unlike the primary visual area, which only receives inputs from its contralateral visual field. Response of the fusiform face area to ipsilateral stimulation depends on the signals crossing over at the corpus callosum. We investigated the distribution of voxel-wise activation to determine whether ipsilateral-dominant voxels exist in the fusiform face area using high spatial resolution functional MRI at 7 T. We further examined the possible functional differences between ipsilateral-dominant and contralateral-dominant voxels. By unilateral visual field stimulation, we detected ipsilateral-dominant voxels in the right fusiform face area. Their distribution was spatially heterogeneous. We tested upright and inverted facial stimulation confined to unilateral visual fields and found that these ipsilateral-dominant voxels had a different functional nature from contralateral-dominant voxels.