Seoul National University · Neuroscience
Professor Hyejin Kang's research lab focuses on understanding the neural mechanisms underlying cognitive and neuropsychiatric symptoms in neurodegenerative diseases, particularly Alzheimer’s disease, using neuroimaging techniques such as SPECT to map regional cerebral blood flow. The lab also investigates the brain's functional network dynamics during complex sensory processing, especially audiovisual integration in speech perception under challenging listening conditions. By combining advanced computational methods like persistent homology and network analysis, the lab explores how brain connectivity changes in health and disease. Their work bridges clinical neuroscience with systems-level brain network analysis to uncover biomarkers and mechanisms of cognitive impairment and sensory processing deficits.
Figures are computed from collected data and may differ slightly.
The aim of this study was to identify brain areas related to apathy or depression in patients with Alzheimer disease (AD). Eighty-one AD patients were enrolled in this prospective study. 99mTc-HMPAO single photon emission computed tomography was performed to evaluate regional cerebral blood flow (rCBF). According to the Neuropsychiatric Inventory subscores of apathy and depression, 9 patients were classified as clinically significant (cs) depressed and non-cs-apathetic (D+) groups and 9 were cla
본 연구는 주민들의 지역에 대한 만족이 지방정부의 중요한 과제로 떠오르는 상황에서 주민들의 지방정부 서비스에 대한 기대불일치가 지역 만족에 어떠한 영향을 미치는지를 살펴보고자 하였다. 이와 함께 기대불일치와 지역에 대한 주민 만족 사이의 관계를 지방정부에 대한 신뢰가 조절할 가능성이 있는지를 확인하였다. 이를 규명하기 위하여 전국 지방자치단체 주민들을 대상으로 조사한 서베이 자료를 분석하였다. 자료를 분석한 결과, 주민들의 기대불일치는 지역만족도와 거주의사에 부정적인 영향을 미친다는 것을 확인하였다. 또한 이러한 양자의 부정적인 관계는 주민들이 속한 지방정부에 대한 신뢰가 높을수록 완화되는 경향을 보였다. 이러한 분석결과는 다음과 같은 함의를 제시할 수 있을 것으로 보인다. 먼저, 지방정부 주민들이 중요하다고 생각 하는 서비스에 대한 만족도를 높이는 방향으로 서비스의 우선순위를 고려해야한다는 정책적 시사점을 도출해볼 수 있다. 또한, 지방정부에 대한 주민들의 신뢰를 높임으로서 정부에
The human brain naturally integrates audiovisual information to improve speech perception. However, in noisy environments, understanding speech is difficult and may require much effort. Although the brain network is supposed to be engaged in speech perception, it is unclear how speech-related brain regions are connected during natural bimodal audiovisual or unimodal speech perception with counterpart irrelevant noise. To investigate the topological changes of speech-related brain networks at all
Supplementary data are available at Bioinformatics online.
This research attempts to examine how organizational characteristics and environmental characteristics of public organization influence adoption and application of the performance evaluation system and pay-for-performance system. In doing so, internal documents and interviews with personnel managers in KAMCO were analyzed and the adoption of system can be divided into three phases. In the process of examining each phase, it was revealed that the factors contributing to the success of establishin
To explain gating of memory encoding, magnetoencephalography (MEG) was analyzed over multi-regional network of negative correlations between alpha band power during cue (cue-alpha) and gamma band power during item presentation (item-gamma) in Remember (R) and No-remember (NR) condition. Persistent homology with graph filtration on alpha-gamma correlation disclosed topological invariants to explain memory gating. Instruction compliance (R-hits minus NR-hits) was significantly related to negative
The present results suggest that late-onset deaf adults showed decreased FA and increased RD, and early-onset deaf adults showed no difference compared with the hearing group. In the late-onset deaf adults, onset-age showed a significantly positive correlation with RD and negative correlation with FA. Duration of deafness was not significantly correlated with the changes. Increased RD indicating demyelination occurred in the brain, and the changes were not limited to the auditory cortex but expa
Our results suggest that oversynchronisation of left A1 connectivity before rTMS of the left A1 and DLPFC is associated with treatment effectiveness.
This study analyzes the factors influencing the organizational performance of schools in Korea, using the 'governance model'. In recent years, the importance of managerial factors in the public sector has been emphasized. To examine whether this emphasis is justified, this study analyzes data collected from the Korean Educational Panel Study wave II and III. The results of the analysis demonstrate that school leaders' managerial actions are important influential factors, as are parental factors
본 연구는 해마가 관여하는 연합기억의 유형을 규명하고자 두 종류의 서로 다른 연합기억 과제를 비교하여, 해마가 활성화 되는 연합기억 과제가 어떤 과제인가를 알아보고자 하였다. 연합 기억의 부호화와 재인 동안 활성화 되는 영역을 정상 성인들(N=16)을 대상으로 fMRI를 이용하여 연구하였다. 연합 기억 과제의 유형에 따라, 명명가능한 선형그림 자극을 그 자극이 제시되었던 위치(좌/우)와 함께 기억하여야 하거나(그림-위치 과제), 인위적으로 짝지워진 다른 선형그림과 함께 기억(그림-그림 과제) 기억 할 것이 요구되었다. 응시 기저 조건에 비하여, 해마는 그림-그림 과제 동안 부호화와 인출 중에 활성화 되었으나 그림-위치 과제 동안은 활성화 되지 않았다. 시각피질과 좌측 전전두엽 및 두정엽의 활성화가 두 과제 모두에서 관찰되었으나 공간적 주의, 또는 탐색이 요구되었을 그림-위치 과제동안에만 우측 상소구에서 활성화가 관찰되었다. 본 연구의 결과는 기억해야 할 정보의 유형의 특성에 따라 해
Purpose : The aim of this study was to identify the brain areas in which reductions of regional cerebral blood flow (rCBF) were correlated with decline of general mental function, measured by Mini-Mental State Examination (MMSE). Materials and Methods : Tc-99m HMPAO brain SPECT was peformed in 9 probable AD patients at the initial and follow-up periods of 1.8 years (average) after the first study. MMSE scores were also measured in both occasions. The mean MMSE score of the initial study 16.4 (ra
목적: 본 연구의 목적은 첫째, 알쯔하이머형 치매의 국소뇌혈류량이 일정 시간이 지난 후 감소되는 양상을 voxel based 분석을 통해 확인하고자 하였다. 둘째, 이들 환자에 있어서 두뇌 특정부위가 임상에서 흔하게 쓰이는 간이정신상태검사인 MMSE-K(Mini-Mental State Examination, Korean version)의 수행과 상관을 보이는 영역이 있는지 살펴보고자 하였다. 대상 및 방법: Tc-99m HMPAO SPECT를 이용해서 9명의 probable 알쯔하이머형 치매 환자군에게 평균 1.8년의 기간을 두고 각각 두 번의 영상(기저영상과 추적검사 영상)을 얻었고, 이를 각각 9명의 정상노인으로부터 얻은 영상과 비교 분석하였다. 각 영상은 공간정규화 이후 소뇌의 활성화에 따라 계수 정규화되었고, SPM99를 사용하여 voxel based 분석을 하였다. 결과: 대조군에 비하여 환자군에서 뇌혈류량의 감소를 보이는 영역이, 기저검사에서 주로 두정측두영역인데 비하여
This study draws on expectation-disconfirmation theory to explore differences between what is expected of the government and perceptions of what the government in fact does and to determine the influence of these differences on trust in government. Confirming the applicability of contact theory, this study also reveals the moderating effect of citizen participation. The results show that the more citizens’ expectations regarding the role of government are not met, the less trust they have in gov
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