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1,012 results on '"Park, Hae-Jeong"'

161. Functional disconnection between the prefrontal and parietal cortices during working memory processing in schizophrenia: a [[sup.15]O][H.sub.2]O PET study

Author

Kim, Jae-Jin, Kwon, Jun Soo, Park, Hae Jeong, Youn, Tak, Kang, Do Hyung, Kim, Myung Sun, Lee, Dong Soo, and Lee, Myung Chul

Subjects
Schizophrenia -- Physiological aspects, Short-term memory -- Physiological aspects, PET imaging -- Research, Prefrontal cortex -- Research, Health, Psychology and mental health
Abstract

Objective: The prefrontal-parietal circuits have been reported to play an important role in working memory. The purpose of this study was to use direct neuroimaging to address whether interregional correlation in the prefrontal-parietal circuits is impaired in schizophrenia. Method: [[sup.15]O][H.sub.2]O positron emission tomography was used to compare regional blood flow changes in 12 schizophrenic and 12 healthy comparison subjects during the n-back sequential-picture working memory task. Interregional correlation was assessed by correlating the regional activation of the lateral prefrontal area with that of other activated areas in each subject group. Results: Dorsolateral prefrontal activation was observed around the right superior frontal sulcus in the healthy subjects, and ventrolateral prefrontal activation below the right inferior frontal sulcus was observed in the schizophrenic patients. Activation in the right lateral prefrontal cortex was significantly correlated with activation in the bilateral inferior parietal region in the healthy subjects but was not correlated with any regional activation in the patients. Conclusions: The findings suggest prefrontal-parietal functional disconnection, particularly prefrontal dissociation and abnormal prefrontal-parietal interaction, during working memory processing in schizophrenia.

Published
2003

162. Large-scale DCMs for resting-state fMRI

Author

Razi, Adeel, Seghier, Mohamed L., Zhou, Yuan, McColgan, Peter, Zeidman, Peter, Park, Hae-Jeong, Sporns, Olaf, Rees, Geraint, and Friston, Karl J.

Subjects
Graph theory, Functional connectivity, Quantitative Biology::Neurons and Cognition, fMRI, Bayesian inference, Methods, Dynamic causal modeling, Large-scale networks, Effective connectivity, Resting state, lcsh:Neurosciences. Biological psychiatry. Neuropsychiatry, lcsh:RC321-571
Abstract

This paper considers the identification of large directed graphs for resting-state brain networks based on biophysical models of distributed neuronal activity, that is, effective connectivity. This identification can be contrasted with functional connectivity methods based on symmetric correlations that are ubiquitous in resting-state functional MRI (fMRI). We use spectral dynamic causal modeling (DCM) to invert large graphs comprising dozens of nodes or regions. The ensuing graphs are directed and weighted, hence providing a neurobiologically plausible characterization of connectivity in terms of excitatory and inhibitory coupling. Furthermore, we show that the use of Bayesian model reduction to discover the most likely sparse graph (or model) from a parent (e.g., fully connected) graph eschews the arbitrary thresholding often applied to large symmetric (functional connectivity) graphs. Using empirical fMRI data, we show that spectral DCM furnishes connectivity estimates on large graphs that correlate strongly with the estimates provided by stochastic DCM. Furthermore, we increase the efficiency of model inversion using functional connectivity modes to place prior constraints on effective connectivity. In other words, we use a small number of modes to finesse the potentially redundant parameterization of large DCMs. We show that spectral DCM—with functional connectivity priors—is ideally suited for directed graph theoretic analyses of resting-state fMRI. We envision that directed graphs will prove useful in understanding the psychopathology and pathophysiology of neurodegenerative and neurodevelopmental disorders. We will demonstrate the utility of large directed graphs in clinical populations in subsequent reports, using the procedures described in this paper.

Published
2017
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177. Task-related modulation of anterior theta and posterior alpha EEG reflects top-down preparation

Author

Park Hae-Jeong and Min Byoung-Kyong

Subjects
Neurosciences. Biological psychiatry. Neuropsychiatry, RC321-571, Neurophysiology and neuropsychology, QP351-495
Abstract

Abstract Background Prestimulus EEG alpha activity in humans has been considered to reflect ongoing top-down preparation for the performance of subsequent tasks. Since theta oscillations may be related to poststimulus top-down processing, we investigated whether prestimulus EEG theta activity also reflects top-down cognitive preparation for a stimulus. Results We recorded EEG data from 15 healthy controls performing a color and shape discrimination task, and used the wavelet transformation to investigate the time course and power of oscillatory activity in the signals. We observed a relationship between both anterior theta and posterior alpha power in the prestimulus period and the type of subsequent task. Conclusions Since task-differences were reflected in both theta and alpha activities prior to stimulus onset, both prestimulus theta (particularly around the anterior region) and prestimulus alpha (particularly around the posterior region) activities may reflect prestimulus top-down preparation for the performance of subsequent tasks.

Published
2010
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185. Interregional metabolic connectivity of 2-deoxy-2[18 F]fluoro-D-glucose positron emission tomography in vagus nerve stimulation for pediatric patients with epilepsy: A retrospective cross-sectional study

Author

Yu, Rita, primary, Park, Hae-Jeong, additional, Cho, Hojin, additional, Ko, Ara, additional, Pae, Chongwon, additional, Oh, Maeng-Keun, additional, Kang, Hoon-Chul, additional, Kim, Heung Dong, additional, Park, Eun-Kyung, additional, Shim, Kyu-Won, additional, Kim, Dong Suk, additional, and Lee, Joon Soo, additional

Published
2018
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