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Dive into the research topics where Tae Hyon Ha is active.

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Featured researches published by Tae Hyon Ha.


Neuroreport | 2005

Sex differences in the human corpus callosum: diffusion tensor imaging study.

Yong-Wook Shin; Dae-Jin Kim; Tae Hyon Ha; Hae-Jeong Park; Won-Jin Moon; Eun Chul Chung; Jong-Min Lee; In Young Kim; Sun I. Kim; Jun Soo Kwon

In order to assess underlying structural differences between the male and female corpus callosum, the fractional anisotropy and volume of the corpus callosum, and also its T1 signal intensity, were measured. The corpus callosum of the 15 normal women and 15 normal men was drawn on the mid-sagittal T1-weighted image, for determining its volume and signal intensity, and this region of interest was projected onto the coregistered fractional anisotropy image, in order to obtain the value for the corpus callosum. We found increased T1 signal intensity and decreased fractional anisotropy in the female corpus callosum, as compared with that of the male. Despite the long-standing debates, the corpus callosum remains a region of sex differences.


Neuroscience Letters | 2005

Fractal dimension of cerebral cortical surface in schizophrenia and obsessive–compulsive disorder

Tae Hyon Ha; Uicheul Yoon; Kyung Jin Lee; Yong Wook Shin; Jong-Min Lee; In Young Kim; Kyoo Seob Ha; Sun I. Kim; Jun Soo Kwon

Schizophrenia and obsessive-compulsive disorder (OCD) are assumed to be neurodevelopmental disorders. To examine the cortical patterns in the two disorders, three-dimensional fractal dimension (FD) of skeletonized cerebral cortical surface was estimated from magnetic resonance (MR) images of 50 patients with schizophrenia, 45 patients with OCD and 26 healthy normal controls. The schizophrenic group had a significantly smaller mean FD than OCD group, and the OCD group than normal controls. The FD revealed a significant interaction effect of group-by-hemisphere, and the FD asymmetry index distinguished the schizophrenic group from normal controls. In logistic regression models, the FD and CSF volume correctly classified 95.6% of the schizophrenics from the controls and 88.0% of the patients with OCD from the controls. In the control and schizophrenic groups, the FD was not associated with any of tissue volume measures. In the OCD group, however, the FD was significantly correlated with gray matter tissue volume and intracranial volume (ICV). The results of the present study suggest that three-dimensional FD of cortical surface may be a sensitive indicator for investigation of the structural brain abnormalities in mental disorders, especially those developmentally disturbed. Further studies to explore regional FD changes in mental disorders and clinical implications of the FD including diagnostic value should be performed in the future.


Neuroscience Letters | 2009

Regional brain gray matter abnormalities in patients with bipolar II disorder: A comparison study with bipolar I patients and healthy controls

Tae Hyon Ha; Kyooseob Ha; Jae Hyoung Kim; Jung Eun Choi

Despite the high prevalence and clinical significance of bipolar II disorder (BD II), the underlying pathophysiology is not well explored in previous studies. The purpose of the current study was to investigate brain gray matter abnormalities in BD II. High resolution magnetic resonance brain images from 23 BD II patients, 23 sex- and age-matched patients with bipolar I disorder (BD I) and 23 healthy controls were acquired and processed according to the optimized voxel-based morphometry protocol. The processed gray matter tissue volumes were compared among the three groups. Both the BD II and BD I group showed gray matter deficits in the ventromedial prefrontal regions, compared to controls. The BD I group had widespread gray matter reductions in the bilateral frontal, temporal, parietal and parahippocampal cortices, compared to controls. However, gray matter reductions in these regions were not found in the BD II group. With a less conservative statistical threshold, the BD II group showed additional gray matter deficits in the anterior limbic cortices. Our data suggest that gray matter deficits in the ventromedial prefrontal and anterior limbic cortices are common in both BD II and BD I. On the other hand, different pattern of gray matter abnormalities between BD II and BD I found in this study supports that two subtypes may have different neurobiological characteristics.


Neuroreport | 2009

White matter alterations in male patients with obsessive-compulsive disorder.

Tae Hyon Ha; Do-Hyung Kang; Jun Sung Park; Joon Hwan Jang; Wi Hoon Jung; Jung-Seok Choi; Jiyoung Park; Myung Hun Jung; Chi-Hoon Choi; Jong Min Lee; Kyooseob Ha; Jun Soo Kwon

To investigate white matter abnormalities in patients with obsessive–compulsive disorder and to clarify the relationship between discrete white matter alterations and obsessive–compulsive symptom dimensions, the fractional anisotropy obtained from 25 male patients and 25 matched normal controls were analyzed. The patients had a significantly lower fractional anisotropy in the left anterior cingulate white matter than the controls. When stratified by clinical symptom dimensions, patients with a predominant aggressive/checking symptom dimension exhibited a significantly lower fractional anisotropy in the left anterior cingulate white matter, whereas patients with a predominant contamination/cleaning symptom dimension showed a significantly higher fractional anisotropy in the bilateral prefrontal white matter. Our findings provide evidence that obsessive–compulsive disorder may be a heterogeneous disease with distinct white matter changes.


Neuroscience Letters | 2011

Similarities and differences of white matter connectivity and water diffusivity in bipolar I and II disorder

Tae Hyon Ha; Ju Young Her; Jae Hyoung Kim; Jae Seung Chang; Hyun Sang Cho; Kyooseob Ha

Differences and similarities in microstructural white matter alterations between bipolar I and bipolar II disorder were investigated. Twelve patients with bipolar I disorder, 12 patients with bipolar II disorder and 22 healthy controls underwent diffusion tensor imaging. Fractional anisotropy (FA) and mean apparent diffusion coefficient (ADC) maps were compared between groups using voxel-based whole brain analyses. Both bipolar I and II groups had a FA decrease in the corpus callosum, cingulate and right prefrontal regions, and a ADC increase in the medial frontal, anterior cingulate, insular and temporal regions, compared to controls. The bipolar I group had a FA decrease in the right temporal white matter and a ADC increase in the frontal, temporal, parietal and thalamic regions, compared to the bipolar II group. The results suggest disrupted integrity of commissural fibers and white matter in the anterior paralimbic structures in bipolar disorder. Relative sparing of the dorsal system and long association fibers may differentiate bipolar II from I disorder.


Psychiatry and Clinical Neurosciences | 2006

Effect of cognitive training focusing on organizational strategies in patients with obsessive‐compulsive disorder

Hee Soo Park; Yong-Wook Shin; Tae Hyon Ha; Min Sup Shin; Young Youn Kim; Young Ho Lee; Jun Soo Kwon

Abstract  The purpose of the present paper was to develop a cognitive training program for patients with obsessive‐compulsive disorder (OCD) and evaluate its effectiveness. Nine 60‐min sessions focusing on the improvement of organizational strategies were given to 15 patients with OCD over a period of 5 weeks. The control group consisted of 15 age‐ and sex‐matched patients also with OCD. The Rey–Osterrieth Complex Figure Test and Korean–California Verbal Learning Test were administered before and after cognitive training. Clinical symptoms were assessed with the Yale–Brown Obsessive‐Compulsive Scale. The memory function in the treatment group improved and their clinical symptoms were alleviated after training, compared to those of the control group. Cognitive training of OCD patients not only improved their memory function, but also alleviated their clinical symptoms. Therefore, cognitive training, focusing on the improvement of organizational strategies, could be an effective treatment modality for patients with OCD.


Human Brain Mapping | 2005

Asymmetry analysis of deformable hippocampal model using the principal component in schizophrenia

Sun Hyung Kim; Jong-Min Lee; Hyun-Pil Kim; Dong Pyo Jang; Yong-Wook Shin; Tae Hyon Ha; Jae-Jin Kim; In Young Kim; Jun Soo Kwon; Sun I. Kim

The hippocampus is thought to play an important role in learning and memory processing, and impairments in memory, attention, and decision making are found commonly in schizophrenia. Although many studies have reported decreases in hippocampal volume in the left hemisphere in schizophrenia, regionally specific hippocampal volume loss has not been revealed consistently using volume analysis. Recently, many studies have analyzed shape asymmetry using 3‐D models; however, inconsistent results have been reported, mainly due to methodologic differences. We therefore used an active, flexible, deformable shape model for surface parameterization, and compared shape asymmetry based on principal component analysis (PCA) in the hippocampi of schizophrenic patients with those of the normal controls. Although the overall pattern of the statistical results did not change according to the number of principal components, the reconstructed results based on six major components were much more distinguishable. Although the left hemispheric hippocampal volume was larger than the right hemispheric was in this study, the difference was not significant. In shape asymmetry analysis, the right hemisphere hippocampus was bilaterally larger than the left hemisphere hippocampus was in the head of the superior CA1 and smaller in the tail and head of the inferior CA1. The asymmetry in the schizophrenia group was statistically smaller than that in the control group through reduction of the left hemisphere hippocampus volume. Hum Brain Mapp, 2005.


Psychiatry Research-neuroimaging | 2010

Nonverbal memory and organizational dysfunctions are related with distinct symptom dimensions in obsessive-compulsive disorder

Joon Hwan Jang; Hee Sun Kim; Tae Hyon Ha; Na Young Shin; Do-Hyung Kang; Jung-Seok Choi; Kyooseob Ha; Jun Soo Kwon

Recent acceptance that obsessive-compulsive disorder (OCD) represents a heterogeneous phenomenon has underscored the need for dimensional approaches to this disorder. However little is known about the relation between neuropsychological functions and symptom dimensions. The purpose of this study was to identify the cognitive deficits correlated with specific symptom dimensions. Thirteen categories in the Yale-Brown Obsessive Compulsive Scale symptom checklist from 144 patients with OCD were analyzed by principal component analysis. Correlations between identified symptom dimensions and neuropsychological functioning, measured by the Boston Qualitative Scoring System, were analyzed. Five factors or dimensions were identified: contamination/cleaning, hoarding, symmetry/ordering, obsessions/checking, and repeating/counting. Dysfunctions in nonverbal memory and organizational strategies were related to the symmetry/ordering dimension and the obsessions/checking dimension, respectively. The results of the present study support a transculturally stable symptom structure for OCD. They also suggest the possibility that nonverbal memory dysfunction and organizational impairment are mediated by distinct obsessive-compulsive dimensions.


Psychiatry and Clinical Neurosciences | 2004

Association between EEG alpha power and visuospatial function in obsessive-compulsive disorder.

Yong-Wook Shin; Tae Hyon Ha; Seong Yoon Kim; Jun Soo Kwon

Abstract  The purpose of the present paper was to determine if frontal activity, measured as electroencephalogram alpha power, correlates with visuospatial functions in obsessive–compulsive disorder (OCD). Electroencephalography and the Rey–Osterrieth Complex Figure Test (RCFT) were performed on 23 patients meeting the Diagnostic and Statistical Manual of Mental Disorders (4th edn; DSM‐IV) OCD criteria. After quantitatively analyzing EEG recordings taken over the frontal, temporal, parietal and occipital regions (F1, F2, T3, T4, P3, P4, O1 and O2), the log transformed absolute power values of the alpha frequencies of the regions were regressed with each RCFT index (copy, immediate recall and delayed recall score). On the frontal region (F1, F2), the RCFT copy score was found to be correlated with the alpha power with regression coefficients that had different directions according to hemisphere (F1, 5.62; F2, −5.26). The result that visuo‐constructional ability represented by the RCFT copy score correlated with frontal activation as measured by decreased alpha power, supports the opinion that visuospatial dysfunction in OCD is not in the visuospatial memory per se but rather that it is mediated by executive function deficit. The opposite correlation directions indicate that greater left frontal activation correlates with a poorer RCFT copy score and that greater right frontal activation correlates with a better copy score. These relationships provide indirect evidence of the possibility that the main pathology of OCD is located in  the left hyperfrontality and that the right hyperfrontality of OCD occurs by a compensatory mechanism.


Progress in Neuro-psychopharmacology & Biological Psychiatry | 2003

N-Methyl-d-aspartate receptor in working memory impairments in schizophrenia: event-related potential study of late stage of working memory process

Kyung-Heup Ahn; Tak Youn; Sang Soo Cho; Tae Hyon Ha; Kyoo Seob Ha; Jun Soo Kwon

Working memory (WM) deficit in schizophrenic patients has been well established. Still, underlying biological substrate of the impairment is not clear. Among neurotransmitter hypotheses of schizophrenia, N-methyl-D-aspartate (NMDA) receptor model is mostly supported, considering that NMDA receptor antagonist can elicit both psychosis and cognitive impairment observed in schizophrenic patients. In current study, to test the neuropsychological and the electrophysiological effects of NMDA receptor in WM, event-related potentials (ERPs) of Sternbergs short-term memory scanning task (SMST) were analyzed in 10 healthy subjects under intravenous administration of a subanesthetic dose of ketamine (0.65 mg/kg/h) or placebo (normal saline). Late positive component (LPC) of ERP was hypothesized to reflect later stage of WM. Brief Psychiatric Rating Scale score was significantly increased (t=-5.75, df=9, P<.001) and correct response rate was significantly decreased (t=2.21, df=9, P=.054) after ketamine administration. Neither reaction time nor LPC latency, which reflect memory scanning time, was changed. Amplitude of LPC was significantly reduced after ketamine administration (z=-2.31, number of observations=120, P=.021). In conclusion, NMDA receptor antagonist administration elicited WM deficit both in behavioral and electrophysiological level. Electrophysiological component reflecting later stage of WM was impaired by NMDA antagonist.

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Kyooseob Ha

Seoul National University

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Jun Soo Kwon

Seoul National University Hospital

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Jae Seung Chang

Seoul National University Bundang Hospital

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Boseok Cha

Seoul National University Bundang Hospital

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Eunsoo Moon

Pusan National University

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Jung Eun Choi

Seoul National University Bundang Hospital

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Taesung Park

Seoul National University

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Yong-Wook Shin

Seoul National University

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