• 대한근전도전기진단의학회지
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• 제20권2호
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• pp.106-111
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• 2018

Transcranial magnetic stimulation (TMS) has been a gold standard for investigating central motor pathways in humans. Diffusion tensor imaging with fiber tractography (DTI FT) is known for its usefulness in detecting white matter lesion in vivo. We investigated the clinical usefulness of elucidating the integrity and continuity of corticospinal tract (CST) by combined use of TMS and DTI FT in this study. We report two cases who have presented with left hemiparesis and evaluated by both TMS and DTI FT; 10-year-old boy with Mitochondrial Encephalomyopathy with Lactic Acidosis and Stroke-like episode syndrome and 20-year-old woman with traumatic brain injury. Combined use of TMS and DTI FT successfully led to localize the brain lesion that might cause motor impairment in patients with abnormal signal intensities in MRI. The results of this study suggest that TMS and DTI FT might provide the detailed information between function and anatomy of the CST, complementarily.

• Investigative Magnetic Resonance Imaging
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• 제17권3호
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• pp.169-180
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• 2013

목적 : 본 연구는 신경망의 인과성을 이해하기 위해 사용되는 방법인 뇌경두개자기자극기 (TMS)를 기능자기공명영상(fMRI) 내에서 동시에 시행하기 위한 적합성을 평가하는데 그 목적이 있다. 대상 및 방법 : TMS 코일을 지지할 수 있도록 비자성의 특징을 갖는 물질인 Polyetherether Keton (PEEK)을 이용하여 홀더를 제작하였다. 컴퓨터 시뮬레이션을 이용하여 MR 스캐너 안에서의 TMS 코일의 위치와 방향에 따른 자기장의 분포를 계산하였다. 또한, TMS 자극시 발생할 수 있는 영상 왜곡을 최소화하면서 fMRI영상을 획득하기 위하여 볼륨과 볼륨 획득 사이 간극 동안 TMS 자극을 가하는 기법을 제안하였다. 결과 : 컴퓨터 시뮬레이션을 통해서 코일 중심의 자기장은 코일에서 거리가 멀어질수록 급격하게 감소함을 확인하였다. 팬텀실험을 통해 fMRI 자극제시는 볼륨간 시간 간격을 100 ms정도 수준에서도 영상 왜곡을 줄이는데 문제가 없음을 확인하였다. 운동 과제 수행과 TMS로 운동 중추 자극시 각각의 뇌반응 분석 연구를 통해 fMRI 측정 중 TMS가 가능함을 확인하였다. 결론 : 본 연구를 통해 fMRI 환경 내에서 관심 영역에 TMS를 가함으로써 뇌 기능의 인과적 연결성 연구를 할 수 있는 기본 도구를 확립하게 되었다.

• The Journal of Korean Physical Therapy
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• 제27권1호
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• pp.38-42
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• 2015

Purpose: Accuracy and variability of movement in daily life require synchronization of muscular activities through a specific chronological order of motor performance, which is controlled by higher neural substrates and/or lower motor centers. We attempted to investigate whether transcranial direct current stimulation (tDCS) over primary sensorimotor areas (SM1) could influence movement variability in healthy subjects, using a tapping task. Methods: Twenty six right-handed healthy subjects with no neurological or psychiatric disorders participated in this study. They were randomly and equally assigned to the real tDCS group or sham control group. Direct current with intensity of 1 mA was delivered over their right SM1 for 15 minutes. For estimation of movement variability before and after tDCS, tapping task was measured, and variability was calculated as standard deviation of the inter-tap interval (SD-ITI). Results: At the baseline test, there was no significant difference in SD-ITI between the two groups. In two-way ANOVA with repeated measurement no significant differences were found in a large main effect of group and interaction effect between two main factors (i.e., group factor and time factor (pre-post test)). However, significant findings were observed in a large main effect of the pre-post test. Conclusion: Our findings showed that the anodal tDCS over SM1 for 15 minutes with intensity of 1 mA could enhance consistency of motor execution in a repetitive-simple tapping task. We suggest that tDCS has potential as an adjuvant brain facilitator for improving rhythm and consistency of movement in healthy individuals.

• 대한의용생체공학회:의공학회지
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• 제32권4호
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• pp.305-311
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• 2011

For effective stimulation with tDCS, spatial focality of induced electrical field(EF) and current density(CD) is one of the important factors to be considered. Recently, there have been some studies to improve the spatial focality via different types of electrodes and their new configurations: some improvements using ring electrodes were reported over the conventional pad electrodes. However, most of these studies assumed isotropic conductivities in the head. In this work, we have investigated the effect of tissue anisotropy on the spatial focality of tDCS with the 4 + 1 ring electrode configuration via a 3-D high-resolution finite element(FE) head model with anisotropic conductivities in the skull and white matter. By examining the profiles of the induced EF from the head models with isotropic and anisotropic conductivities respectively, we found that the spatial focality of the induced EF significantly drops and get diffused due to tissue anisotropy. Our analysis suggests that it is critical to incorporate tissue anisotropy in the effective stimulation of the brain via tDCS.

• Journal of Acupuncture Research
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• 제18권2호
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• pp.18-26
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• 2001

Purpose : To evaluate the effects of electroacupuncture on regional cerebral blood flow (rCBF) at acupoints suggested by oriental medicine to be related to the treatment of cerebrovascuiar diseases. Materials and Methods : Rest/electroaeupuncture-stimulation Tc-99m ECD brain SPECT using a same-dose subtraction method was performed on 5 normal male volunteers (age range from 27 to 30 years) using electroacupuncture at acupoint, ST 36. In the control study, needle location was chosen on a non-meridian focus 1cm posterior to the right fibular head. All images were spatially normalized and the differences between rest and acupuncture stimulation were statistically analyzed using SPM$^{(R)}$ for Windows$^{(R)}$. Results : Electroacupuncture applied at ST36 increased rCBF in the left hemisphere, that is, the left parietal lobe(angular gyrus), the left temporal lobe, the left inferior frontal lobe around rectus gyrus and the left cerebellar hemisphere, a part of the left inferior frontal lobe. In the control stimulation, no significant rCBF increase was observed. Conclusion : The results demonstrate that electroacupuncture increases rCBF in the contralateral cerebral hemisphere.

• Annals of Rehabilitation Medicine
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• 제42권6호
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• pp.777-787
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• 2018

Objective To examine the long-term effects of the low-frequency repetitive transcranial magnetic stimulation (LF-rTMS) combined with task-specific training on paretic hand function following subacute stroke. Methods Sixteen participants were randomly selected and grouped into two: the experimental group (real LF-rTMS) and the control group (sham LF-rTMS). All the 16 participants were then taken through a 1-hour task-specific training of the paretic hand. The corticospinal excitability (motor evoke potential [MEP] amplitude) of the non-lesioned hemisphere, and the paretic hand performance (Wolf Motor Function Test total movement time [WMFT-TMT]) were evaluated at baseline, after the LF-rTMS, immediately after task-specific training, 1 and 2 weeks after the training. Results Groups comparisons showed a significant difference in the MEP after LF-rTMS and after the training. Compared to the baseline, the MEP of the experimental group significantly decreased after LF-rTMS and after the training and that effect was maintained for 2 weeks. Group comparisons showed significant difference in WMFT-TMT after the training. Only in the experimental group, the WMFT-TMT of the can lifting item significantly reduced compared to the baseline and the effect was sustained for 2 weeks. Conclusion The results of this study established that the improvement in paretic hand after task-specific training was enhanced by LF-rTMS and it persisted for at least 2 weeks.

• Journal of Korean Neurosurgical Society
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• 제29권2호
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• pp.222-230
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• 2000

Purpose : Resection of the epileptogenic zone in the parietal and occipital lobes may be relevant although only few studies have been reported. Methods : Eight patients with parietal epilepsy and nine patients with occipital epilepsy were included for this study. Preoperatively, all had video-EEG monitoring with extracranial electrodes, MRI, 3D-surface rendering of MRI using Allegro(ISG Technologies Inc., Toronto, Canada), and PET scans. Sixteen patients underwent invasive recording with subdural grid. Eight had parietal resection including the sensory cortex in two. Seven had partial occipital resection. Two underwent total unilateral occipital lobectomy. The extent of the resection was made based mainly on the data of invasive EEG recordings, MRI, and 3D-surface rendering of MRI, not on the intraoperative electrocorticographic findings as usually done. During resection, electrocortical stimulation was performed on the motor cortex and speech area. Results : Out of eight patients with parietal epilepsy, three had sensory aura, two had gustatory aura, and two had visual aura. Six of nine patients with occipital epilepsy had visual auras. All had complex partial seizures with lateralizing signs in 15 patients. Four had quadrantopsia. One had mild right hemiparesis. Abnormality in MRI was noticed in six out of eight parietal epilepsy and in eight out of nine occipital epilepsy. 3D-surface rendering of MRI visualized volumetric abnormality with geometric spatial relationships adjacent to the normal brain, in all of parietal and occipital epilepsy. Surface EEG recording was not reliable in localizing the epileptogenic zone in any patient. The subdural grid electrodes can be implanted on the core of the structural abnormality in 3D-reconstructed brain. Ictal onset zone was localized accurately by subdural grid EEGs in 16 patients. Motor cortex in nine and sensory speech area in two were identified by electrocortical stimulation. Histopathologic findings revealed cortical dysplasia in 10 patients ; tuberous sclerosis was combined in two, hamartoma and ganglioglioma in one each, and subpial gliosis in six. Eleven patients were seizure free at follow-up of 6 months to 37 months(mean 19.7 months) after surgery. Seizures recurred in two and were unchanged in one. Six produced transient sensory loss and one developed hemiparesis and tactile agnosia. One revealed transient apraxia. Two patients with preoperative quadrantopsia developed homonymous hemianopsia. Conclusion : This study suggests that surgical treatment was relevant in parietal and occipital epilepsies with good surgical outcome, without significant neurologic sequelae. Neuroimaging studies including conventional MRI, 3Dsurface rendering of MRI were necessary in identifying the epileptogenic zone. In particular, 3D-surface rendering of MRI was very helpful in presuming the epileptogenic zone in patients with unidentifiable lesion in the conventional MRI, in planning surgical approach to lesions, and also in making a decision of the extent of the epileptogenic zone in patients with identifiable lesion in conventional MRI. Invasive EEG recording with the subdural grid electrodes helped to confirm a core of the epileptogenic zone which was revealed in 3D-surface rendered brain.

• 인지과학
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• 제26권4호
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• pp.393-433
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• 2015

창의성은 독창적이고 유용한 아이디어를 산출할 수 있는 능력을 말한다. 현대 사회의 많은 문제들을 해결하고 인류의 복지를 증진시키기 위해 창의성의 기전을 이해하고 이를 증진할 수 있는 방안에 대한 연구는 매우 중요하다. 창의성은 매우 이질적이고 복합적인 능력으로서 이를 하나의 능력으로 개념화하는 것은 적절하지 않다. 따라서 학계에서는 창의성의 개별 구성 요소를 중심으로 창의성의 기전에 대한 연구가 활발하게 이루어지고 있다. 본 개관 연구에서는 창의성의 주요한 구성 요소인 확산적 사고, 통찰, 관계적 사고 그리고 예술적 창의성에 대한 인지신경과학 연구들을 소개한다. 여러 연구 결과를 종합적으로 고려한 결과, 창의성의 인지신경학적 기전과 관련하여 우반구가 좌반구보다 우세하다는 가설은 실험적 증거에 의해 지지되지 않았다. 또한, 창의성과 관련하여 특정 뇌 영역의 중요성이 일관되게 보고되고 있지 않으며, 다양한 뇌 영역의 활동성이 창의성과 관계된다는 연구 결과가 혼재하고 있다. 이러한 상이한 연구 결과가 관찰되는 이유는 창의성의 각 구성 요소의 이질성 뿐 아니라, 연구에 사용된 과제의 특수성과 과제에 의해 유발된 인지적 전략의 차이에 의해 뇌 활동이 달라지기 때문인 것으로 해석할 수 있다. 본 개관 연구에서는 창의성의 요소 별 뇌기반과 창의성의 증진에 대하여 우수한 연구 방법을 사용하여 탁월한 연구 성과를 이룬 대표적인 사례들을 소개하고 현행 연구들의 제한점과 후속 연구의 방향을 제시한다.

• IMMUNE NETWORK
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• 제3권3호
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• pp.235-241
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• 2003

Background: The protective immunity against tuberculosis (TB) involves both CD4+ T cells and CD8+ T cells. In our previous study, we defined four Mycobacterium tuberculosis derived peptide epitopes specific for HLA-$A^*0201$ restricted CD8+ T cells ($ThyA_{30-38}$, $RpoB_{127-135}$, $85B_{15-23}$, $PstA1_{75-83}$). In this study, we investigated the immune responses induced by these peptide specific CD8+ T cells in latently and chronically infected people with TB. Methods: We characterized these peptide specific CD8+ T cell population present in PBMC of both TB patients and PPD+healthy people using IFN-${\gamma}$elispot assay, intracellular staining and HLA-A2 dimer staining. Results: The frequency of peptide specific CD8+ T cell was in the range of 1 to 25 in $1.7{\times}10^5$ PBMC based on ex vivo IFN-${\gamma}$ elispot assay, demonstrating that these peptide specific CD8+ T cell responses are induced in both TB patients and PPD+ people. Short term cell lines (STCL) specific for these peptides proliferated in vitro and secreted IFN-${\gamma}$ upon antigenic stimulation in PPD+ donors. Lastly, HLA-$A^*0201$ dimer assays indicated that $PstA1_{75-83}$ specific CD8+ T cell population in PPD+ healthy donors is heterogeneous since approximately 25~33% of $PstA1_{75-83}$ specific CD8+ T cell population in PPD+ healthy donors produced IFN-${\gamma}$ upon peptide stimulation. Conclusion: Our results suggest that MHC class I restricted CD8+ T cell mediated immune responses to M. tuberculosis infection are induced in both TB patients and PPD + people; however, the CD8+ T cell population is functionally heterogeneous.

• 대한임상검사과학회지
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• 제50권2호
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• pp.211-215
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• 2018

이 연구의 목적은 운동피질 주변의 뇌종양 환자를 대상으로 수술 중 피질척수로를 보존하고 운동 능력을 더 정확하게 평가하기 위함이다. 경두개운동유발전위는 위양성(false positive)과 위음성(false negative)이 혼재하는 검사이기 때문에 수술 중 검사상 파형의 변화가 없었다 할 지라도 검사의 내용을 완전히 신뢰할 수 없다. 보다 자세한 검사를 위해 대뇌피질을 선택적으로 자극할 수 있는 직접피질자극검사를 시행하였다. 직접피질자극 검사를 시행한 2케이스 에서는 수술 중 피질이 담당하는 부위를 찾고 지속적으로 진폭의 변화를 확인하며 검사할 수 있어 운동경로를 보존하며 수술 할 수 있었다. 하지만 직접피질 자극검사를 시행하지 않고 경두개운동유발전위 검사만을 시행한 환자에서는 수술 후 환자의 운동 능력이 감소되는 것을 경험할 수 있었다. 위와 같은 결과를 볼 때 직접피질자극 검사는 매우 유용한 검사이고 뇌종양 수술 시 경두개운동유발전위 검사와 병행하여 환자에게 올 수 있는 후유장애를 줄일 수 있는 방법이다.