• The Journal of Korean Physical Therapy
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• 제22권6호
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• pp.91-98
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• 2010

Neurostimulation approaches have been developed and explored to modulate neuroplastic changes of cortical function in human brain. As one of the most primary noninvasive tools, transcranial direct current stimulation (tDCS) was extensively studied in the field of neuroscience. The alternation of cortical neurons depending on the polarity of the tDCS has been used for improving cognitive processing including working memory, learning, and language in normal individuals, as well as in patients with neurological or psychiatric diseases. In addition, tDCS has great advantages: it is a non-invasive, painless, safe, and cost-effective approach to enhance brain function in normal subjects and patients with neurological disorders. Numerous previous studies have confirmed the efficacy of tDCS. However, tDCS has not been considered for clinical applications and research in the field of physical therapy. Therefore, this review will focus on the general principles of tDCS and its related application parameters, and provide consideration of motor behavioral research and clinical applications in physical therapy.

• Biomedical Science Letters
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• 제18권4호
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• pp.428-434
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• 2012

Epilepsy is a chronic neurological disease showing a symptom of repeated seizures without any other physical disorders. Among the diagnostic examination for epilepsy, the electroencephalogram (EEG) has been known as an important test. This study aimed to investigate the EEG with photic stimulation in the pediatric epilepsy patients. They underwent digital sleep and waking EEGs or waking EEGs with photic stimulation. Epilepsy type, seizure history, and season of occurring seizure were analyzed. Epilepsy patients showed more response during the period of photic-on and eye close at the frequency of 10~20 Hz during the EEG activation procedure. Photoparoxysmal response (PPR) was shown in 206 patients out of total 1,551 epilepsy patients. PPR was appeared more frequently during summer and winter seasons, and especially in the patients who had a history of seizure. During the PPR, EEG pattern showed spike (77.18%), theta (9.71%), and spike + theta (13.11%). On the other hand, beta and theta waves were not significantly changed by photic stimulation. However, alpha wave was decreased and delta wave was increased by photic stimulation (P<0.05). These changes may be due to temporarily altered electrophysiological function of the epileptic patient's brain by the photic stimulation. There was no difference in the EEG pattern between the left and right side in the brain. In conclusion, condition of photic-on with closed eyes and frequency of 10~20 Hz during the procedure of EEG activation could be appropriate for obtaining a definite photoparoxysmal response in the electroencephalogram of the pediatric epilepsy patients.

• Journal of Korean Neurosurgical Society
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• 제57권1호
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• pp.6-11
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• 2015

Objective : Neuropathic pain causes patients feel indescribable pain. Deep Brain Stimulation (DBS) is one of the treatment methods in neuropathic pain but the action mechanism is still unclear. To study the effect and mechanism of analgesic effects from DBS in neuropathic pain and to enhance the analgesic effect of DBS, we stimulated the ventral posterolateral nucleus (VPL) in rats. Methods : To observe the effect from VPL stimulation, we established 3 groups : normal group (Normal group), neuropathic pain group (Pain group) and neuropathic pain+DBS group (DBS group). Rats in DBS group subjected to electrical stimulation and the target is VPL. Results : We observed the behavioral changes by DBS in VPL (VPL-DBS) on neuropathic pain rats. In our study, the pain score which is by conventional test method was effectively decreased. In specific, the time of showing withdrawal response from painful stimulation which is not used measuring method in our animal model was also decreased by DBS. Conclusion : The VPL is an effective target on pain modulation. Specifically we could demonstrate changes of pain response duration which is not used, and it was also significantly meaningful. We thought that this study would be helpful in understanding the relation between VPL-DBS and neuropathic pain.

• Science of Emotion and Sensibility
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• 제5권4호
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• pp.67-75
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• 2002

The purpose of this study is to assess the ability of balance control in virtual moving surround stimulation using head mount display (HMD) device and force platform in patients with brain injury. Fifteen patients with stroke (mean age 54.47 yrs) and fifteen healthy normal persons participated. COP parameters were obtained total path distance, frequency of anterior-posterior and medial-lateral component by FFT analysis, weight-spectrum analysis in the two different conditions; (1) during comfortable standing with opened or closed eyes, (2) during virtual moving surround stimulation delivered using HMD with four different moving pattern. Moving patterns consisted of close-far, superior-inferior lilting (pitch) , right-left tilting (roll) and horizontal rotation (yaw) movement. In all parameters, the test-retest reliability was high. Also, the construct validity of virtual moving surround stimulation was excellent (p＜0.05). A posturographic balance assessment system equiped with virtual moving surround stimulation using HMD is considered clinically useful in evaluation of balance control in patients with brain injury.

• Journal of Korean Neurosurgical Society
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• 제57권3호
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• pp.152-158
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• 2015

Objective : The purpose of this study to develop new deep-brain stimulation system for long-term use in animals, in order to develop a variety of neural prostheses. Methods : Our system has two distinguished features, which are the fully implanted system having wearable wireless power transfer and ability to change the parameter of stimulus parameter. It is useful for obtaining a variety of data from a long-term experiment. Results : To validate our system, we performed pre-clinical test in Parkinson's disease-rat models for 4 weeks. Through the in vivo test, we observed the possibility of not only long-term implantation and stability, but also free movement of animals. We confirmed that the electrical stimulation neither caused any side effect nor damaged the electrodes. Conclusion : We proved possibility of our system to conduct the long-term pre-clinical test in variety of parameter, which is available for development of neural prostheses.

• Journal of information and communication convergence engineering
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• 제8권2호
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• pp.205-211
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• 2010

In this study, a Magnetic stimulation Pulse Train control technique is introduced and applied to Flyback converter operating in discontinuous conduction mode. In contrast to the conventional pulse width modulation control scheme, the principal idea of a Magnetic stimulation Pulse Train is to achieve output voltage regulation using high and low power pulses. The proposed technique is applicable to any converter operating in discontinuous conduction. However, this work mainly focuses on Flyback topology. In this paper, the main mathematical concept of the new control algorithm is introduced and simulations as well as experimental results are presented.

• Journal of the Optical Society of Korea
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• 제20권1호
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• pp.88-93
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• 2016

Recently laser speckle contrast (LSC) imaging has become a widely used optical method for in vivo assessment of blood flow in the animal brain. LSC imaging is useful for monitoring brain hemodynamics with relatively high spatio-temporal resolution. A speckle contrast imaging system has been implemented with electrical sensory stimulation apparatus. LSC imaging is combined with optical intrinsic signal imaging in order to measure changes in cerebral blood flow as well as neural activity in response to electrical sensory stimulation applied to the hindlimb region of the mouse brain. We found that blood flow and oxygen consumption are correlated and both sides of hindlimb activation regions are symmetrically located. This apparatus could be used to monitor spatial or temporal responses of cerebral blood flow in animal disease models such as ischemic stroke or cortical spreading depression.

• Journal of the Ergonomics Society of Korea
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• 제33권5호
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• pp.395-405
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• 2014

Objective: The aim of this study is to investigate 1) somatotopic arrangement of the second and third fingers in SI area 2) difference of neural activation in the SI area produced by stimulation with different frequencies 3) correlation between the intensity of tactile perception by different stimulus intensity and the level of brain activation measurable by means of fMRI. Background: Somatosensory cortex can obtain the information of environmental stimuli about "where" (e.g., on the left palm), "what" (e.g., a book or a dog), and "how" (e.g., scrub gently or scrub roughly) to organism. However, compared to visual sense, the neural mechanism underlying the processing of specific electrotactile stimulus is still unknown. Method: 10 right-handed subjects participated in this study. Non-painful electrotactile stimuli were delivered to two different finger tips of right hand. Functional brain images were collected from 3.0T MRI using the single-shot EPI method. The scanning parameters were as follows: TR and TE were 3000, 35ms, respectively, flip angle 60, FOV $24{\times}24cm$, matrix size $64{\times}64$, slice thickness 4mm (no gap). SPM5 was used to analyze the fMRI data. Results: Significant activations produced by the stimulation were found in the SI, SII, the subcentral gyrus, the precentral gyrus, and the insula. In all participants, statistically significant activation was observed in the contralateral SI area and the bilateral SII areas by the stimulation on the fingers but ipsilaterally dominant. The SI area representing the second finger generally located in the more lateral and inferior side than that of the third finger across all the subjects. But no difference in brain area was found for the stimulation of the fingers by different frequencies. And two typical patterns were observed on the relationship between the perceived psychological intensity and the amount of voxels in the primary sensory cortex during the stimulation. Conclusion: It was possible to discriminate the representation sites in the SI by electrotactile stimulation of digit2 and digit3. But we could not find the differences of the brain areas according to different stimulation frequencies from 3 to 300Hz. Application: The results of the study can provide a deeper understanding of somatosensory cortex and offer the information for tactile display for blinds.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 한국감성과학회 2004년도 추계학술대회 논문집
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• pp.18-18
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• 2004

• Sleep Medicine and Psychophysiology
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• 제1권2호
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• pp.145-155
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• 1994

The neurophysiological study has been widely used in the search of the relation between brain and behavior. The basic techniques for the animal experiments of this kind such as stereotaxic techniques, lesioning methods, the methods of electrical stimulation and confirmation of histological location were simply reviewed. Nevertheless, the importance of complementary neurochemical, neuroanatomical and behavioral studies can not be neglected.