• The Journal of Korean Association of Computer Education
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• v.13 no.6
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• pp.35-42
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• 2010

In this paper, the characteristics of online game addiction have been analyzed using fMRI. The fMRI images are taken from six target subjects who are around 20 years old, right-handed, and undergraduate male students with online game stimulations. The images are processed using SPM5, and statistical analysis showed following characteristics. First, online game stimuli produces an activation in BA18 of brain, and the Pearson correlation coefficient between the activation intensity of BA18 area and the addiction index value is very highly as .94. Second, the Pearson correlation coefficient is .75 between addiction index of subjects and activation index of the mesencephalon. From these observations, we found that the online game stimuli were processed as visual stimuli by subjects' brain, and the subject's brain with bigger addiction index processes more actively from the online game stimuli. Also, the online game stimuli activate the mesolimbic system, and therefore these findings may contribute for comparing the mechanism between general addiction and online game addiction.

• The Journal of Korean Physical Therapy
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• v.21 no.1
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• pp.81-87
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• 2009

Purpose: Human brain was lateralized to dominant or non-dominant hemisphere, and could be reorganized by the processing of the motor learning. We reported four cases which showed the changes of the cortical activation patterns resulting from two weeks of training with the serial reaction time task. Methods: Four right-handed healthy subjects were recruited, who was equally divided to two training conditions (right hand training or left hand training). They were assigned to train the serial reaction time task for two weeks, which should press the corresponding four colored buttons as fast as accurately as possible when visual stimulus was presented. Before and after two weeks of training, reaction time and function magnetic resonance image (fMRI) was acquired during the performance of the same serial reaction time task as the training. Results: The reaction time was significantly decreased in all of subjects after training. Our fMRI result showed that widespread bilateral activation at the pre scanning was shifted toward the focused activation on the contralateral hemisphere with progressive motor learning. However, the bilateral activation was still remained during the performance of the non-dominant hand. Conclusion: These findings showed that the repetitive practice of the serial reaction time task led to increase the movement speed and accuracy, as described by motor learning. Such motor learning induced to change the cortical activation pattern. And, the changed pattern of the cortical activation resulting from motor learning was different each other in accordance with the hand dominance.

• Journal of the Korean Society of Radiology
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• v.17 no.2
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• pp.185-190
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• 2023

This study designed and produced stimuli in the form of canned images of fun humor, character, quirky, and sexy humor, and measured the signal values (SI) of the hippocampus associated with memory through fMRI analysis. The results of 20 participants showed that there were differences in SI values according to gender and age, and the fun humor image stimuli had the highest SI values. Men showed higher SI values for fun humor image stimuli, while women showed higher SI values for character humor image stimuli. In addition, those in their 20s showed higher SI values for fun humor image stimuli, while those in their 30s showed higher SI values for quirky humor image stimuli. Considering these findings, it is expected that more effective results can be obtained by utilizing fun humor images and characters in package design.

• Progress in Medical Physics
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• v.20 no.4
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• pp.277-289
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• 2009

Recently, functional MRI has been used to investigate the neurobiological mechanisms of acupuncture and the specificity of acupoint. The group data tend to be regarded as more important than the individual data in the most of previous studies. This study was designed to investigate the effect of the variability of individual data on the group results. A functional MRI (fMRI) of the whole brain was performed in fifteen healthy subjects during placebo and acupuncture stimulations at the ST36 acupoint. After remaining at rest for 30 seconds, the acupuncture was inserted and twisted at the rate of 2 Hz for 45 seconds and then the acupuncture was removed immediately. This process was repeated three times. Individual and group analyses were performed by voxel-based analyses using SPM2 software. Visual inspections of the activation and deactivation maps from individual sessions have shown the large variability across fifteen subjects. This means that the group data reflected the brain activation responses of only a few subjects. We suggest that the individual data should be presented to demonstrate the effect of acupuncture.

• Communications for Statistical Applications and Methods
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• v.12 no.1
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• pp.241-252
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• 2005

In this study we suggest that the spatial correlation structure of the brain fMRI data be used to characterize the functional connectivity of the brain. For some concussion and recovery data, we examine how the correlation structure changes from one step to another in the data analyses, which will allow us to see the effect of each analysis to the spatial correlation or the functional connectivity of the brain. This will lead us to spot the processes which cause significant changes in the spatial correlation structure of the brain. We discuss whether or not we can decompose correlation matrices in terms of its causes of variations in the data.

• 한국HCI학회:학술대회논문집
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• 2008.02b
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• pp.501-506
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• 2008

본 연구에서는 가상현실을 이용한 단서노출치료가 흡연자의 니코틴 갈망수준을 감소시키는지를 알아보았다. 이를 위하여 8명의 흡연청소년을 대상으로 6회기의 가상환경 단서노출치료를 실시하였다. 또한 단서노출치료 실시전과 후에 흡연관련 사진과 중립사진을 제시하는 동안 참가자들의 뇌를 기능성 자기공명영상장치(fMRI)로 측정하였다. 그 결과 단서노출실시 전에는 prefrontal cortex(PFC), Anterior cingulate gyrus(ACC) 영역을 비롯한 7개의 영역이 활성화되었고, 단서노출치료 후에는 right middle frontal gyrus, right uncus, left medial frontal gyrus, right fusiform gyrus, 그리고 right superior frontal gyrus 영역이 활성화되었다. 단서노출치료 전과 후의 비교에 서는 PFC가 관찰되었다. 본 연구의 결과로 흡연자의 흡연 갈망은 감소되었으며, 가상현실단서노출치료는 흡연자들 뿐 아니라 여러 물질의존자들의 치료에 유용한 방법이 될 것이라는 것을 시사한다.

• Proceedings of the IEEK Conference
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• 2002.07b
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• pp.802-805
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• 2002

In the three-dimensional domain image expressed with two-dimensional slice images, such as fMRI images and multi-slice CT images, we propose the three-dimensional domain automatic segmentation for the purpose of extracting region. In this paper, we segmented each domain from the fMRI images of the head of people and monkey. We used the neural network "Pulse-Coupled Neural Network" which is one of the models of visual cortex of the brain based on the knowledge from neurophysiology as the technique. By using this technique, we can segment the region without any learning. Then, we reported the result of division of each domain and extraction to the fMRI slice images of human's head using "three-dimensional Pulse-Coupled Neural Network" which is arranged and created the neuron in the shape of a three-dimensional lattice.

• Proceedings of the KSMRM Conference
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• 2001.11a
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• pp.104-104
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• 2001

Purpose： In this study, we investigated the possible motor pathways of hemiplegic stroke patients usin combined TMS and BOLD fMRI approach and evaluated the correlation between TMS a fMRI methods. Method： Four subjects, who demonstrated left hemiplegia after stroke, are included. TMS was performed using a Dantec Mag2 stimulator (Dantec Company, USA) in single puls mode with figure eight-shaped coil. Following TMS localization, The BOLD T2＊-weight images were acquired with echo planar imaging sequence (TR = 1.2 sec, TE = 60 msec, and flip angle = 90). Motor activation was studied by means of a repetitive fing flexion-extension task. The stimulation protocol comprised 10 cycles of alternating activati and rest (10 images per cycle). Total 60 cycles were performed and each cycle take abou 1.5 sec. The resulting images were then analyzed with STIMULATE (CMRR, U, o Minnesota) to generate functional maps using a student t-test (p < 0.0005) and cluste analysis.

• Annual Conference on Human and Language Technology
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• 2004.10d
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• pp.315-318
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• 2004

The purpose of this study is to examine the neuroanatomical areas related with onomatopoeia (sound-imitated word). Using the block-designed fMRI, whole-brain images (N=11) were acquired during lexical decisions. We examined how the lexical information initiates brain activation during visual word recognition. The onomatopoeic word recognition activated the bilateral occipital lobes and superior mid-temporal gyrus.

• Journal of Radiation Protection and Research
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• v.38 no.3
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• pp.157-165
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• 2013

To determine the factors affecting the external radiation dose rates of patients undergoing PET-MRI examinations and to assess the trends of these differences, we measured the changes in the dose rates of $^{18}F$-FDG during a set period of time for each body region. Consistent with theoretical predictions, the dose rate decreased over time in patients undergoing PET-MRI examinations. Furthermore, immediately after the $^{18}F$-FDG injection, the dose rate in the chest region was the highest, followed by the abdominal region, the head region, and the foot region. The dose rate decreased drastically as time passed, by 2.47-fold, from $339.23{\pm}74.70mSv\;h^{-1}$ ($6.73{\pm}5.79$ min) at the time point immediately after the $^{18}F$-FDG injection to $102.71{\pm}26.17mSv\;h^{-1}$ ($136.11{\pm}25.64$ min) after the examination. In the foot region, there were no significant changes over time, from $32.05{\pm}20.23mSv\;h^{-1}$ ($6.73{\pm}5.79$ min) at the time point immediately after the $^{18}F$-FDG injection, to $23.89{\pm}9.14mSv\;h^{-1}$ ($136.11{\pm}25.64$ min) after the examination. The dose rate is dependent on the individual characteristics of the patient, and differed depending on the body region and time point. However, the dose rates were higher in patients who had a lower body weight, shorter stature, fewer urinations, lower fluid intake, and history of diabetes mellitus. To decrease radiation exposure, it is difficult or impossible to change factors inherent to the patient, such as sex, age, height, body weight, obesity, and history of diabetes mellitus. However, factors which can be changed, such as the $^{18}F$-FDG dose, fasting time, fluid intake, number of urinations, and contrast agent dose can be controlled to minimize the external radiation exposure of the patient.