• Investigative Magnetic Resonance Imaging
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• v.3 no.1
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• pp.53-59
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• 1999

Purpose : To evaluate the usefulness of functional MR imaging (fMRI) for language mapping and determination of language lateralization. Materials and Methods : Functional maps of the language area were obtained during word generation tasks and decision task in ten volunteers (7 right handed, 3 left-handed). MR examinations were performed at 1.5T scanner with EPI BOLD technique. Each task consisted of three resting periods and two activation periods with each period of 30 seconds. Total acquisition time was 162 sec. SPM program was used for the postprocessing of images. Statistical comparisons were performed by using t-statistics on a pixel-by- pixel basis after global normalization by ANCOVA. Activation areas were topographically analyzed (p>0.001) and activated pixels in each hemisphere were compared quantitatively by lateralization index. Results : Significant activation signals were demonstrated in 9 of 10 volunteers. Activation signals were found in the premotor and motor cortices, the inferior frontal, inferior parietal, and mid-temporal lobes during stimulation tasks. In the right handed seven volunteers, activation of language areas was lateralized to the left side. Verb generation task produced stronger activation in the language areas and higher value of lateralization index than noun generation task or decision task. Conclusion : fMRI could be a useful non-invasive method for language mapping and determination of language dominance.

• Journal of Chest Surgery
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• v.23 no.1
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• pp.81-89
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• 1990

A total of 178 patients with primary lung cancer who had undergone complete resection of the tumor in combination with complete mediastinal lymphadenectomy were reviewed at the Department of Thoracic and Cardiovascular Surgery of Yonsei Medical Center from January 1980 through July 1989. Materials; 1. There were 45 men and 33 women ranging of age from 25 to 78 years with a mean age of 55.4 years. 2. Histological types were squamous carcinoma in 115 cases [64.6%] adenocarcinoma in 42 cases [23.6 %], bronchioloalveolar carcinoma in 9 cases [5.1%], large cell carcinoma in 8 cases [4.5 %] and small cell carcinoma in 4 cases [2.2%] Results were summarized as follows: 1. The size of primary tumor was not directly proportional to the frequency of mediastinal lymph node metastasis. [P =0.0567] 2. The histologic types of the primary tumor did not related to the incidence of mediastinal lymph node metastasis. [P >0.19] 3. The chance of mediastinal lymph node metastasis in the case with lung cancer located in right middle lobe[31.8%, N=22] and left lower lobe [31.4%, N=32] were the highest and the lowest was the one located in right lower lobe, while over all incidence of mediastinal lymph node metastasis in this series was 25.4 % [N=55]. 4. The rate of mediastinal lymph node metastasis without evidence of regional and hilar lymph node metastasis was 13%. [N=23] The chance of mediastinal lymph node involvement without N1 lymph node metastasis was 16.3 % [N=17] in both upper lobes and 8.2 % [N=6] in both lower lobes. It was statistically significant that the tumors in the upper lobes had greater chance of the mediastinal lymph node metastasis without N1 than the tumors in the lower lobes. 5. In this series majority of the patients with lung cancer the mediastinal lymph node metastasis from the tumor in each pulmonary lobes usually occurs via ipsilateral tracheobronchial and paratracheal lymphatic pathway. Especially the lung cancer located in lower lobes can metastasize to subcarinal, paraesophageal and inferior pulmonary ligamental lymph node through the lymphatic pathway of inferior pulmonary ligament. It can be speculated that in some cases of this series otherwise mediastinal lymph node metastasis can also occur with direct invasion to the parietal pleura and to the mediastinal lymph node via direct subpleural lymphatic pathway .

• The Korean Journal of Pain
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• v.9 no.2
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• pp.399-402
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• 1996

Endoscopic transthoracic sympathectomy (ETS) has recently become estabilished as a successful treatment for severe palmar and axillary hyperhidrosis. Descriptions have been published of neurolytic, operative and alternative endoscopic procedures involving thermocoagulation, laser coagulation, or or nonvideo-assisted ganglionectomy using equipment not widely available, with low morbidity and excellent results. All methods have advantage and disadvantages. A 19-year-old male who suffered from severe hyperhidrosis on face, palms and axillary areas, has been initially treated with stellate ganglion block in other pain clinic. He was transfered to our pain clinic for endoscopic thoracic sympathectomy. The patient was intubated left side 34 Fr. double lumen tube and positioned left semi-lateral position for right sympathectomy. Right side pneumothorax was created by clamping the ipsilateral side of the double lumen tube and aspiration of air. 11-mm trocar was introduced through incision at the third intercostal space in anterior axillary line, and then additional two 11-mm and 5-mm trocar was introduced through second and fifth intercostal space in mid axillary line. The lung was gently retracted and the parietal pleura over the heads of the appropriate ribs excised using 5-mm sharp insulated coagulating microprocesss. The T4, T3, and T2 ganglions, as well as accompanying rami communicantes, and other branchs arising from upper thoracic nerves to the brachial plexus and surrounding tissues were carefully dissected, coagulated. During sympathectomy, skin temperature of middle was continuously monitored. Elevation of palmar skin temperature intraoperatively indicated an adequate sympathectomy with a definite therapeutic effect. A No. 28 Fr. thoracotomy tube was introduced through a troca under video guidance, placed under water seal after the lung was reinflated. the controlateral side was performed same procedure. After bilateral sympathectomy, chest tubes were removed, and then, he was discharged 2 days after operation with great satisfaction. The ETS provides a well-tolerated, cost-effective alternative to thoracic sympathectomy for primary hyperhidrosis and sympathetic mediated neuropathic pain disorder. And T2 ganglion is considered the key ganglion for the treatment of primary hyperhidrosis. The low incidence of compensatory sweating may by explained by the limited extent of the sympathectomy.

• Science of Emotion and Sensibility
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• v.22 no.3
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• pp.3-20
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• 2019

With advancements in technology of virtual reality, it is used for various purposes in many fields such as medical care and healthcare, but as the same time there are also increasing reports of nausea, eye fatigue, dizziness, and headache from users. These symptoms of motion sickness are referred to as cybersickness, and various researches are under way to solve the cybersickness problem because it can cause inconvenience to the user and cause adverse effects such as discomfort or stress. However, there is no official standard for the causes and solutions of cybersickness at present. This is also related to the absence of tools to quantitatively measure the cybersickness. In order to overcome these limitations, this study proposed quantitative and objective cybersickness evaluation method. We measured 128-channel EEG waves from ten participants experiencing visually stimulated virtual reality. We calculated the relative power of delta and alpha in 11 regions (left, middle, right frontal, parietal, occipital and left, right temporal lobe). Multiple regression models were obtained in a stepwise manner with the motion sickness susceptibility questionnaire (MSSQ) scores indicating the susceptibility of the subject to the motion sickness. A multiple regression model with the highest under the area ROC curve (AUC) was derived. In the multiple regression model derived from this study, it was possible to distinguish cybersickness by accuracy of 95.1% with 11 explanatory variables (P_D.MF, P_D.LP, P_D.MP, P_D.RP, P_D.MO, P_A.LF, P_A.MF, P_A.RF, P_A.LP, P_A.RP, P_A.MO). In summary, in this study, objective response to cybersickness was confirmed through 128 channels of EEG. The analysis results showed that there was a clearly distinguished reaction at a specific part of the brain. Using the results and analytical methods of this study, it is expected that it will be useful for the future studies related to the cybersickness.

• The Korean Journal of Nuclear Medicine
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• v.32 no.3
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• pp.238-249
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• 1998

Purpose: To localize and compare the neural basis of verbal and visual human working memory, we performed functional activation study using $H_2^{15}O$ PET. Materials and Methods: Repeated $H_2^{15}O$ PET scans with one control and three different activation tasks were performed on six right-handed normal volunteers. Each activation task was composed of 13 match-ing trials. On each trial, four targets, a fixation dot and a probe were presented sequentially and subject's task was to press a response button to indicate whether or not the probe was one of the previous targets. Short meaningful Korean words, simple drawings and monochromic pictures of human faces were used as matching objects for verbal or visual memory. All the images were spatially normalized and the differences between control and activation states were statistically analyzed using SPM96. Results: Statistical analysis of verbal memory activation with short words showed activation in the left Broca's area, promoter cortex, cerebellum and right cingulate gyrus. In verbal memory with simple drawings, activation was shown in the larger regions including where activated with short words and left superior temporal cortex, basal ganglia, thalamus, prefrontal cortex, anterior portion of right superior temporal gyrus and right infero-lateral frontal cortex. On the other hand, the visual memory task activated predominantly right-sided structures, especially inferior frontal cortex, supplementary motor cortex and superior parietal cortex. Conclusion: The results are consistent with the hypothesis of the laterality and dissociation of the verbal and visual working memory from the invasive electrophysiological studies and emphasize the pivotal role of frontal cortex and cingulate gyrus in working memory system.

• The Korean Journal of Nuclear Medicine
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• v.32 no.5
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• pp.397-402
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• 1998

Purpose: The purpose of this study was to evaluate the phenomenon of diaschisis in the cerebellum and cerebral cortex in patients with pure basal ganglia hemorrhage using cerebral blood flow SPECT. Materials and Methods: Twelve patients with pure basal ganglia hemorrhage were studied with Tc-99m ECD brain SPECT. Asymmetric index (AI) was calculated in the cerebellum and cerebral cortical regions as |$C_R-C_L$/$(C_R-C_L){\times}200$, where $C_R$and $C_L$ are the mean reconstructed counts for the right and left ROIs, respectively. Hypoperfusion was considered to be present when AI was greater than mean +2 SD of 20 control subjects. Results: Mean AI of the cerebellum and cerebral cortical regions in patients with pure basal ganglia hemorrhage was significantly higher than normal controls (p<0.05): Cerebellum ($18.68{\pm}8.94$ vs $4.35{\pm}0.94$, $mean{\pm}SD$), thalamus ($31.91{\pm}10.61$ vs $2.57{\pm}1.45$), basal ganglia ($35.94{\pm}16.15$ vs $4.34{\pm}2.08$), parietal ($18.94{\pm}10.69$ vs $3.24{\pm}0.87$), frontal ($13.60{\pm}10.5$ vs $4.02{\pm}2.04$) and temporal cortex ($15.92{\pm}11.95$ vs $5.13{\pm}1.69$). Ten of the 12 patients had significant hypoperfusion in the contralateral cerebellum. Hypoperfusion was also shown in the ipsilateral thalamus (n=12), ipsilateral parietal (n=12), frontal (n=6) and temporal cortex (n=10). Conclusion: Crossed cerebellar diaschisis (CCD) and cortical diaschisis may frequently occur in patients with pure basal ganglia hemorrhage, suggesting that CCD can develop without the interruption of corticopontocerebellar pathway.

• Korean Journal of Cognitive Science
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• v.27 no.2
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• pp.159-219
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• 2016

Mathematical ability is important for academic achievement and technological renovations in the STEM disciplines. This study concentrated on the relationship between neural basis of mathematical cognition and its mechanisms. These cognitive functions include domain specific abilities such as numerical skills and visuospatial abilities, as well as domain general abilities which include language, long term memory, and working memory capacity. Individuals can perform higher cognitive functions such as abstract thinking and reasoning based on these basic cognitive functions. The next topic covered in this study is about individual differences in mathematical abilities. Neural efficiency theory was incorporated in this study to view mathematical talent. According to the theory, a person with mathematical talent uses his or her brain more efficiently than the effortful endeavour of the average human being. Mathematically gifted students show different brain activities when compared to average students. Interhemispheric and intrahemispheric connectivities are enhanced in those students, particularly in the right brain along fronto-parietal longitudinal fasciculus. The third topic deals with growth and development in mathematical capacity. As individuals mature, practice mathematical skills, and gain knowledge, such changes are reflected in cortical activation, which include changes in the activation level, redistribution, and reorganization in the supporting cortex. Among these, reorganization can be related to neural plasticity. Neural plasticity was observed in professional mathematicians and children with mathematical learning disabilities. Last topic is about mathematical creativity viewed from Neural Darwinism. When the brain is faced with a novel problem, it needs to collect all of the necessary concepts(knowledge) from long term memory, make multitudes of connections, and test which ones have the highest probability in helping solve the unusual problem. Having followed the above brain modifying steps, once the brain finally finds the correct response to the novel problem, the final response comes as a form of inspiration. For a novice, the first step of acquisition of knowledge structure is the most important. However, as expertise increases, the latter two stages of making connections and selection become more important.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.32 no.4
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• pp.293-298
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• 2010

Purpose: The objective of the present study was to determine the capability of electrospun silk fibroin as a biomaterial template for bone formation when mixed with nano-hydoxyapatite in vivo. Materials and Methods: Ten New Zealand white rabbits were used for this study and bilateral round shaped defects were formed in the parietal bone (diameter: 8.0 mm). The electrospun silk fibroin was coated by nano-hydroxyapatite and grafted into the right parietal bone (experimental group). The left side (control group) did not receive a graft. The animals were sacrificed at 6 weeks and 12 weeks, humanly. The microcomputerized tomogram (${\mu}CT$) was taken for each specimen. Subsequently, they were undergone decalcification and stained for the histological analysis. Results: The average value of all measured variables was higher in the experimental group than in the control at 6 weeks after the operation. BMC in the experimental group at 6 weeks after operation was $48.94{\pm}19.25$ and that in the control was $26.17{\pm}16.40$ (P = 0.027). BMD in the experimental group at 6 weeks after operation was $324.59{\pm}165.24$ and that in the control was $173.03{\pm}120.30$ (P = 0.044). TMC in the experimental group at 6 weeks after operation was $19.50{\pm}6.00$ and that in the control was $10.52{\pm}6.20$ (P = 0.011). TMD in the experimental group at 6 weeks after operation was $508.88{\pm}297.57$ and that in the control was $273.54{\pm}175.91$ (P = 0.06). Gross image of both groups showed higher calcification area at 12 weeks than them in 6 weeks. The average value of ${\mu}CT$ analysis was higher at 12 weeks than that in 6 weeks in both groups. BMC in the experimental group at 12 weeks after operation was $51.21{\pm}8.81$ and that in the control was $33.47{\pm}11.13$ (P = 0.010). BMD in the experimental group at 12 weeks after operation was $323.39{\pm}21.54$ and that in the control was $197.75{\pm}76.23$ (P = 0.012). TMC in the experimental group at 12 weeks after operation was $21.44{\pm}5.30$ and that in the control was $13.31{\pm}4.17$ (P = 0.008). TMD in the experimental group at 12 weeks after operation was $524.47{\pm}19.37$ and that in the control was $299.60{\pm}136.20$ (P = 0.016). Conclusion: The rabbit calvarial defect could be successfully repaired by electrospun silk nano-fiber combined with nano-hydroxyapatite.

• Sleep Medicine and Psychophysiology
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• v.27 no.2
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• pp.67-76
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• 2020

Objectives: Brain maturation involves brain lateralization and asymmetry to achieve efficient information processing and cognitive controls. This study elucidates normal brain maturation change during the gap between ages 6-9 and age 14-17 using resting EEG. Methods: An EEG dataset was acquired from open source MIPDB (Multimodal Resource for Studying Information Processing in the Developing Brain). Ages 6-9 (n = 24) and ages 14-17 (n = 26) were selected for analysis, and subjects with psychiatric illness or EEG with severe noise were excluded. Finally, ages 6-9 (n = 14) and ages 14-17 (n = 11) were subjected to EEG analysis using EEGlab. A 120-sec length of resting EEG when eyes were closed was secured for analysis. Brain topography was compartmentalized into nine regions, best fitted with brain anatomical structure. Results: Absolute power of the delta band and theta band in ages 6-9 was greater than that of ages 14-17 in the whole brain, and, also is relative power of delta band in frontal compartment, which is same line with previous studies. The relative power of the beta band of ages 14-17 was greater than that of ages 6-9 in the whole brain. In asymmetry evaluation, relative power of the theta band in ages 14-17 showed greater power in the left than right frontal compartment; the opposite finding was noted in the parietal compartment. For the alpha band, a strong relative power distribution in the left parietal compartment was observed in ages 14-17. Absolute and relative power of the alpha band is distributed with hemispheric left lateralization in ages 14-17. Conclusion: During the gap period between ages 6-9 and ages 14-17, brain work becomes more complicated and sophisticated, and alpha band and beta band plays important roles in brain maturation in typically developing children.

• Korean Journal of Cognitive Science
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• v.28 no.1
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• pp.1-26
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• 2017

This study investigated the cortical generators of P300 in college students with schizotypal traits by using an auditory oddball paradigm, event-related potentials (ERPs) and standardized low resolution brain electromagnetic tomography (sLORETA) model. We also investigated the relationship between the current density of P300 and the clinical symptoms of schizophrenia. Based on the scores of Schizotypal Personality Questionnaire(SPQ), schizotypal trait (n=37) and control (n=42) groups were selected. For the measurement of P300, an auditory oddball paradigm, in which frequent standard tones (1000Hz) and rare target tones (1500Hz) were presented randomly, was used. Participants were required to count the number of the target tones during the task and report this at the end of the experiment. The two groups did not differ significantly in the accuracy of the oddball task. The schizotypal trait group showed significantly smaller P300 amplitudes than control group. In terms of source localization, both groups showed the P300 current density over bilateral frontal, parietal, temporal and occipital lobes. However, the schizotypal trait group showed significantly reduced activations in the left superior temporal gyrus and the right middle temporal gyrus, but increased activations in both left inferior frontal gyrus and right superior frontal gyrus compared to the control group. Furthermore, a negative correlation between the current density of the right superior frontal gyrus and SPQ disorganization score was found in the schizotypal trait group. These findings indicate that the individuals with schizotypal traits have dysfunctions of frontal and temporal areas, which are known to be the source of P300, as observed in patients with schizophrenia. In addition, the present results indicate that the disorganization score, rather than total score, of the SPQ is useful in predicting the risk of future schizophrenia.