• Journal of Ginseng Research
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• v.16 no.3
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• pp.183-189
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• 1992

Effect of the standardized ginseng extract(G115) on the central monoaminergic systems were investigated in comparison with that of halcperidol in rats. Immediately after sacrificed by decapitation, the strlata and frontal cortex were removerl. Concentations of the monoamines dopamine and serctorLin and their metabolites were deterinintd by HPLC-EC. G115 increased the concentration of 5-HIAA and DOPAC/UA ratio in striatum. However, dopaminrrgic neuronal activities were not affected by G115 that decreased the concentratio,Is of 5-HT and 5-HIAA in frontal cortex. G115 in combination with apomorphine significantly irlcreased the concentration of DA and S-HT but decreased the DO PAC/DA ratio and 5-HIAA/5-HT ratio only in frontal cortex. These results suggest that G115 like HPD inhibits the activity of nigrostriatal dopamine neuron in striatum. However, unlike HPD it activates central monoaminergic neuron activity in frontal cortex.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1996.04a
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• pp.210-210
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• 1996

Changs in the glutamatergic nervous system following AF64A injection into lateral ventricle were studied in rats. Rats were treated with the infusion of AF64A (3mM) into lateral ventricle At a week after the infusion of AF64A into lateral ventricle, rats were sacrified and each brain resions was dissected ; striatum, hippocampus and frontal cortex. At these resions, total glutamate and other amino acids levels. [$^3$H]Mk801 binding sites and glutamine synthetase activity were measured using HPLC-ECD, ligand binding assay and enzyme activity assay, respectively. The levels of total glutamate were decreased in striatum, hippocampus and frontal cortex Also, the levels of total glycine and taurine were decreased in all examined regions. Furthermore, the levels of total aspartate and GABA were decreased in both hippocampus and frontal cortex but these didn't alter in striatum. Additionally, the levels of total glutamine were decreased in both striatum and frontal cortex. The u\numbers of [$^3$H]MK801 binding sites were differently dffected in each brain resions ; the decrease in striatum, the increase in frontal cortex and no change in hippocampus Glutamine synthetase activity in striatum was significantly decreased. But, that in both hippocampus and frontal cortex didn't alter These results suggest that changes in the glutamatergic nervous system in three regions are induced by following AF64A injection into lateral ventricle in rats.

• The Journal of Korean Physical Therapy
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• v.15 no.3
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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.

• Journal of the Ergonomics Society of Korea
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• v.33 no.5
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• pp.377-386
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• 2014

Objective: In this study, we used resting-state fMRI data to map differences in functional connectivity between a comprehensive set of 8 distinct cortical and subcortical brain regions in healthy controls and Internet addicts. We also investigated the relationship between resting state connectivity strength and the level of psychopathology (ex. score of internet addiction scale and score of Barratt impulsiveness scale). Background: There is a lot of evidence of relationship between Internet addiction and impaired inhibitory control. Clinical evidence suggests that Internet addicts have a high level of impulsivity as measured by behavioral task of response inhibition and a self report questionnaire. Method: 15 Internet addicts and 15 demographically similar non-addicts participated in the current resting-state fMRI experiment. For the connectivity analysis, regions of interests (ROIs) were defined based on the previous studies of addictions. Functional connectivity assessment for each subject was obtained by correlating time-series across the ROIs, resulting in $8{\times}8$ matrixs for each subject. Within-group, functional connectivity patterns were observed by entering the z maps of the ROIs of each subject into second-level one sample t test. Two sample t test was also performed to examine between group differences. Results: Between group, the analysis revealed that the connectivity in between the orbito frontal cortex and inferior parietal cortex, between orbito frontal cortex and putamen, between the orbito frontal cortex and anterior cingulate cortex, between the insula and anterior cingulate cortex, and between amydgala and insula was significantly stronger in control group than in the Internet addicts, while the connectivity in between the orbito frontal cortex and insula showed stronger negative correlation in the Internet addicts relative to control group (p < 0.001, uncorrected). No significant relationship between functional connectivity strength and current degree of Internet addiction and degree of impulsitivy was seen. Conclusion: This study found that Internet addicts had declined connectivity strength in the orbitofrontal cortex (OFC) and other regions (e.g., ACC, IPC, and insula) during resting-state. It may reflect deficits in the OFC function to process information from different area in the corticostriatal reward network. Application: The results might help to develop theoretical modeling of Internet addiction for Internet addiction discrimination.

• The Korean Journal of Physiology and Pharmacology
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• v.8 no.6
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• pp.295-300
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• 2004

Serotonin (5-hydroxytroptamine, 5-HT) has been shown to affect the induction of long-term potentiation (LTP) in the cortex such as the hippocampus, the visual cortex and the prefrontal cortex. Fluoxetine, as a selective serotonin reuptake inhibitor, is used in the management of a wide variety of psychological diseases. To study the effect of fluoxetine on the induction of LTP, we recorded the field potential in layer II/III of the frontal cortex from 3-wk-old. LTP was induced in horizontal input by theta burst stimulation (TBS). TBS with two-folds intensity of the test stimulation induced LTP, which was blocked by application of D-AP5 $(50 {\mu}M)$, an NMDA receptor antagonist. Whereas bath application of 5-HT $(10 {\mu}M)$ inhibited the induction of LTP, treatment with the 5-HT depleting agent, para-chloroamphetamine $(PCA,\;10{\mu}M)$, for 2hr did not affect the induction of LTP. Bath application of fluoxetine (1, 3, and $10 {\mu}M)$ suppressed the induction of LTP in concentration-dependent manner, however, fluoxetine did not inhibit the induction of LTP in 5-HT-depleted slices. These results indicate that fluoxetine may inhibit the induction of LTP by modulating serotonergic mechanism in the rat frontal cortex.

• Korean Journal of Biological Psychiatry
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• v.25 no.1
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• pp.1-8
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• 2018

Insomnia is a common sleep-related symptom which occurs in many populations, however, the neural mechanism underlying insomnia is not yet known. The hyperarousal model explains the neural mechanism of insomnia to some extent, and the frontal cortex dysfunction has been known to be related to primary insomnia. In this review, we discuss studies that applied resting state and/or task-related functional magnetic resonance imaging to demonstrate the deficits/dysfunctions of functional activation and network in primary insomnia. Empirical evidence of the hyperarousal model and proposed relation between the frontal cortex and other brain regions in primary insomnia are examined. Reviewing these studies could provide critical insights regarding the pathophysiology, brain network and cerebral activation in insomnia and the development of novel methodologies for the diagnosis and treatment of insomnia.

• Korean Journal of Cognitive Science
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• v.16 no.4
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• pp.255-270
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• 2005

Memory for repeated items is better if they are repeated in a spaced than in a massed fashion (Sparing effect). To investigate the neural mechanisms of sparing effect and successful encoding, lags of repetition were manipulated at encoding stage in an event-related MU study. The behavioral data showed typical spacing effect on recognition judgment, and greater activity for items that were repeated in a spaced fashion than for items that were repeated in a massed fashion has been observed in dorsolateral frontal cortex(DLFC) and ventrolateral frontal cortex(VLFC) of left hemisphere. These conical regions also showed greater activity for novel items than for items that were repeated in a massed fashion. These findings suggest that sparing effect and its relevant successful encoding are attributed to higher level of attentional control and semantic processing.

• Archives of Pharmacal Research
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• v.19 no.1
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• pp.23-29
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• 1996

Changes in dopaminergic activities were investigated after the intracerebroventricular (icv) administration of ethylcholine aziridium (AF64A) in rats. The levels of dopamine (DA) and metabolites, the activities of tyrosine hydroxylase (TH) and monoamine oxidase (MAO), and the specific binding sites of dopamine receptros in striata, hippocampus, and frontal cortex were assessed 6 days after the AF64A treatment with 3 nmol/each ventrcle. In frontal cortex, the levels of DA and metabolities were significantly decreased without changes in metabolites/DA ratios in the AF64A-treated groups. In contrast, the ratios of metabolites/DA were significantly decreased in striatum and hippocampus in the AF64A treatment. The activity of TH in frontal cortex was significantly decreased. However, that in other areas was not changed. Also the activity of MAO-A was not changed in the studied brain regions. However, the activity of MAO-B in striatum was significantly increased with no change in other areas. The specific binding sites of dopamine D1 and D2 receptors were increased in AF64A-treated frontal cortex. However, those were not changed in striatum and hippocampus except the small decreased specific binding sites of dopamine D-1 receptors in striatum after AF64A treatment. These results indicate that the dopaminergic activity was altered in AF64A treatment. Furthermore, it suggest that the decreased dopaminergic activities in each brain regions might be differently affected by AF64A treatment.

• Archives of Pharmacal Research
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• v.20 no.1
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• pp.39-45
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• 1997

Changes in glutamatergic nervous activities following intracerebroventricular (icv) administration of ethylcholine aziridinium (AF64A) were studied in rats. The levels of total glutamate, those of glutamate in cerebrospinal fluid (CSF) and in extracellular fluid (ECF) of striatum, the activities of glutamine synthetase (GS), glutaminase and glutamate dehydrogenase (GDH) and the specific binding sites of $[^3H]$MK801 in striatum, hippocampus and frontal cortex were assessed a week after the infusion of AF64A (3 nmol) into lateral ventricle. The levels of total glutamate were significantly decreased in striatum, hippocampus and frontal cortex after AF64A treatment. Although the levels of glutamate in CSF weren't changed after AF64A treatment, the levels of glutamate in ECF of striatum were significantly decreased (62.6%). GS activities in striatum were significantly decreased. But, glutaminase activities in striatum were significantly increased. However, the activities of GS and glutaminase in frontal cortex and hippocampus weren't changed. Although GDH activities in frontal cortex were significantly decreased, those in striatum and hippocampus weren't altered. The striatal densities of $[^3H]$MK 801 binding sites were increased without changes in its affinity. Also, the specific binding sites of $[^3H]$MK801 were increased in frontal cortex but not in hippocampus. These results indicate that the glutamatergic nervous activities were altered with the infusion of AF64A into lateral ventricle. Furthermore, it suggest that the decreased levels of glutamate after AF64A treatment may affect the change in the other parameters of glutamatergic neuronal activities.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.695-698
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• 2001

본 연구에서는 생활공간에서의 음 환경이 인체에 미치는 영향을 조사하기 위하여 긍정감성을 유발하는 음환경으로서의 '명상음악'과 부정감성을 유발하는 음환경으로서의 '마루가 삐그덕거리는 소음'을'제시하였을 때 전두엽의 부위별 활성화의 변화를 관찰하기 위하여 뇌전도를 측정하였다. 연구결과, 명상음악을 청취시에는 안정상태에 비하여 좌측전두엽이 더 활성화되는 반면에 소음환경에서는 우측전두엽이 더 활성화됨을 관측할 수 있었다.