• Physical Therapy Korea
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• v.10 no.3
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• pp.17-27
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• 2003

Repetitive transcranial magnetic stimulation (rTMS) modulates cortical excitability beyond the duration of the rTMS trains themselves. Depending on rTMS parameters, a lasting inhibition or facilitation of cortical excitability can be induced. Therefore, rTMS of high or low frequency over motor cortex may change certain aspects of motor learning performance and cortical activation. This study investigated the effect of high and low frequency subthreshold rTMS applied to the motor cortex on motor learning of sequential finger movements and brain activation using functional MRI (fMRI). Three healthy right-handed subjects (mean age 23.3) were enrolled. All subjects were trained with sequences of seven-digit rapid sequential finger movements, 30 minutes per day for 5 consecutive days using their left hand. 10 Hz (high frequency) and 1 Hz (low frequency) trains of rTMS with 80% of resting motor threshold and sham stimulation were applied for each subject during the period of motor learning. rTMS was delivered on the scalp over the right primary motor cortex using a figure-eight shaped coil and a Rapid(R) stimulator with two Booster Modules (Magstim Co. Ltd, UK). Functional MRI (fMRI) was performed on a 3T ISOL Forte scanner before and after training in all subjects (35 slices per one brain volume TR/TE = 3000/30 ms, Flip angle $60^{\circ}$, FOV 220 mm, $64{\times}64$ matrix, slice thickness 4 mm). Response time (RT) and target scores (TS) of sequential finger movements were monitored during the training period and fMRl scanning. All subjects showed decreased RT and increased TS which reflecting learning effects over the training session. The subject who received high frequency rTMS showed better performance in TS and RT than those of the subjects with low frequency or sham stimulation of rTMS. In fMRI, the subject who received high frequency rTMS showed increased activation of primary motor cortex, premotor, and medial cerebellar areas after the motor sequence learning after the training, but the subject with low frequency rTMS showed decreased activation in above areas. High frequency subthreshold rTMS on the motor cortex may facilitate the excitability of motor cortex and improve the performance of motor sequence learning in normal subject.

• Korean Journal of Biological Psychiatry
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• v.24 no.4
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• pp.175-187
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• 2017

Transcranial direct current stimulation (TDCS) is a clinically safe and effective method of delivering weak electric current to modulate cortical activities. And based on the cumulating scientific evidences, the method is recommended to treat major depressive disorder (MDD) and other psychiatric disorders. In this paper, we review the development of TDCS in the rising field of neuromodulation. Then with suggested biochemical and physical mechanism of TDCS, we summarize the reported cases of using TDCS to alleviate major neuropsychiatric disorders. And, in particular, the treatment of MDD is highlighted as an illustrative example of using TDCS. We discuss here the therapeutic potentials of this method in psychiatry. And in closing remarks, we evaluate the current technical limitations and suggest the future directions of this method in both the clinical and research aspects.

• Proceedings of the Acoustical Society of Korea Conference
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• 1998.06c
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• pp.291-296
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• 1998

In the experiment carried out on 20 college students, recorded were frontal, temporal and occipital EEG, skin conductance response, skin conductance level, heart rate and respiration rate during listening to two music fragments with different affective valences and white noise administered immediately after negative visual stimulation. Analysis of physiological patterns observed during the experiment suggests that affective auditory stimulation with music is able to selectively modulate autonomic and cortical activity evoked by preceding aversive visual stimulation and to restore initial baseline levels. On other hand, physiological responses to white noise, which does not possess emotion-eliciting capabilities, evokes response typical for orienting reaction after the onset of a stimulus and is rapidly followed by habituation. Observed responses to white noise were similar to those specific to attention only and had no evidence for any emotion-related processes. Interpretation of the obtained data is considered in terms of the role of emotional and orienting significance of stimuli, dependence of effects on the background physiological activation level and time courses of attention and emotion processes. Physiological parameters are summarized with regard to their potential utility in differentiation of psychological processes induced by auditory stimuli.

• The Journal of Korean Physical Therapy
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• v.36 no.1
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• pp.39-44
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• 2024

Purpose: Cybersickness is a type of motion sickness induced by virtual reality (VR) or augmented reality (AR) environments that presents symptoms including nausea, dizziness, and headaches. This study aimed to investigate how cathodal transcranial direct current stimulation (tDCS) alleviates motion sickness symptoms and modulates brain activity in individuals experiencing cybersickness after exposure to a VR environment. Methods: This study was performed on two groups of healthy adults with cybersickness symptoms. Subjects were randomly assigned to receive either cathodal tDCS intervention or sham tDCS intervention. Brain activity during VR stimulation was measured by 38-channel functional near-infrared spectroscopy (fNIRS). tDCS was administered to the right temporoparietal junction (TPJ) for 20 minutes at an intensity of 2mA, and the severity of cybersickness was assessed pre- and post-intervention using a simulator sickness questionnaire (SSQ). Result: Following the experiment, cybersickness symptoms in subjects who received cathodal tDCS intervention were reduced based on SSQ scores, whereas those who received sham tDCS showed no significant change. fNIRS analysis revealed that tDCS significantly diminished cortical activity in subjects with high activity in temporal and parietal lobes, whereas high cortical activity was maintained in these regions after intervention in subjects who received sham tDCS. Conclusion: These findings suggest that cathodal tDCS applied to the right TPJ region in young adults experiencing cybersickness effectively reduces motion sickness induced by VR environments.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2009.11a
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• pp.183-185
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• 2009

As imaging technology develops, magnetic resonance imaging (MRI) techniques have contributed to the understanding of brain function by providing anatomical structure of the brain and functional imaging related to information processing. Manganese-enhanced MRI (MEMRI) techniques can provide useful information about functions of the nervous system. However, systematic studies regarding information processing of pain have not been conducted. The purpose of this study was to detect brain activation during painful electrical stimulation using MEMRI with high spatial resolution. Male Sprague-Dawley rats (250-300 g) were divided into 3 groups: normal control, sham stimulation, and electric stimulation. Rats were anesthetized with 2.5% isoflurane for surgery. Polyethylene catheter (PE-10) was placed in the external carotid artery to administrate mannitol and MnCl2. The blood brain barrier (BBB) was broken by 20% D-mannitol under anesthesia mixed with urethane and a-chloralose. The hind limb was electrically stimulated with a 2Hz (10V) frequency while MnCl2 was infused. Brain activation induced by electrical stimulation was detected using a 4.7 T MRI. Remarkable signal enhancement was observed in the primary sensory that corresponds to sensory tactile stimulation at the hind limb region. These results suggest that signal enhancement is related to functional activation following electrical stimulation of the peripheral receptive field.

• Journal of Acupuncture Research
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• v.20 no.4
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• pp.66-84
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• 2003

Objectve : Recent stuides suggested that there is a strong correlation between acupuncture stimulation and its cortical activation. Another study showed that either positive or negative BOLD effects could be observed depending on anatomical structure in acupuncture. Methods : 1) Subjects and paradigms: Two separate stimulation paradigms were performed in this study. To see the effects of electro-acupuncture stimulation on K7(Fuliu), the experiment was carried out on six healthy volunteers, using the gradient echo sequence with the 3.0T whole-body MRI system(ISOL). After the needle insertion on right K7(Fuliu), 2 Hz of electric stimulation was given for 30 seconds, repeated five times, with 30 seconds' intervals. During the intervals while there was no electro-stimulation, the subjects performed motor task as a reference. The image analysis including motion correction, talairach transformation, and smoothing was done using SPM99. Results: The electro-acupuncture stimulation on K7(Fuliu) activated Brodmann's Areas of 9, 19, 23, 24, 31, 32, 39 which may be the central pathways of the electro-acupuncture stimulation on K7(Fuliu) and those brain areas may be related with the function of the electro-acupuncture stimulation on K7(Fuliu).

• Journal of The Korean Society of Integrative Medicine
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• v.11 no.2
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• pp.109-117
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• 2023

Purpose : Transcranial direct current stimulation is noninvasive method of cerebral cortical stimulation applied as an intervention to facilitate recovery in stroke patients. The purpose of this study was to examine the effects of transcranial direct current stimulation on depression and anxiety in stroke patients with the aim to finding a reliable method to reduce depression and anxiety in stroke patients. Methods : This study was conducted at A hospital located in D city from December 2022 to February 2023. Patients diagnosed with stroke were selected according to predefined study criteria and divided into two groups. 9 patients in experimental group underwent transcranial direct current stimulation and traditional occupational therapy, while 9 patients in the control group underwent sham transcranial direct current stimulation and traditional occupational therapy for 20 min per session 3 times per week for a total of 8 weeks. Beck depression inventory (BDI) and Beck anxiety inventory (BAI) were used to evaluate depression and anxiety in the patients before and after intervention. Wilcoxon signed rank test was used to compare differences before to after intervention. Mann-Whitney U test was used to compare the two groups. Differences with p<.05 were considered statistically significant. Results : First, both the experimental and control groups presented significant statistical difference before and after intervention on depression (p<.01). Comparison of two groups after intervention showed significant statistical difference in depression (p<.05). Second, the groups presented significant statistical difference before and after intervention on anxiety (p<.01). After intervention, the two groups showed significant statistical difference in anxiety (p<.05). Conclusion : Results of the present study demonstrated the effects of transcranial direct current stimulation on depression and anxiety in stroke patients, suggesting it may be a useful method of rehabilitation in this patient population; as such, further studies are warranted.

• Journal of Korean Neurosurgical Society
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• v.30 no.11
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• pp.1300-1307
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• 2001

Purposes : This study reports the possible causes of seizure recurrence in patients underwent previous epilepsy surgery, and surgical strategy for resection of the additional epileptogenic zone locating at the distant area to the site of first resection. Methods : A total of 10 patients with previous surgery due to intractable epilepsy were studied. Five of these underwent standard temporal lobectomy, four extratemporal resection, and one corticoamygdalectomy. Seizure outcome of these were class III-IV. Evaluation methods for reoperation included MRI, 3D-surface rendering of MRI, PET, prologned video-EEG recording with surface electrodes and subdural grid electrodes. Additional resection was done in the frontal lobe in two, in the temporal lobe in three, in the parietal lobe in two, and in the supplementary sensori-motor area in two. Tumor in the superior frontal gyrus in the left hemisphere was removed in one patient. Extent of resection was decided based on the results of ictal subdural grid EEGs and MRI findings. Awake anesthesia and electrocortical stimulation were performed in the two patients for defining the eloquent area. Results : Histopathologic findings revealed extratemporal cortical dysplasia in six, hippocampal sclerosis and cortical dysplasia of the temporal neocortex in one, neuronal gliosis in two, and meningioma in one. Previous pathology of the five patients with cortical dysplasia in the second operation was hippocampal sclerosis plus cortical dysplasia of the temporal neocortex. After reoperation, seizure outcomes were class I in six, class II in three, class III in one at the mean follow-up period of 17.5 months. Characteristically, patients in class II-III after reoperation showed histopathologic findings of hippocampal sclerosis plus temporal neocortical cortical dysplasia plus extratemporal cortical dysplasia. Conclusions : Seizure recurrence after epilepsy surgery was related with the presence of an additional epileptogenic zone distant to the site of first operation, and the majority of the histopathology of the surgical specimens was cortical dysplasia. In particular, hippocampal sclerosis plus temporal neocortical cortical dysplasia was highly related with seizure recurrence in patients with previous operation. In these patients, multimodal evaluation methods were necessary in defining the additional epileptogenic zone.

• Animal cells and systems
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• v.2 no.1
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• pp.65-69
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• 1998

The hippocampus and prefrontal cortex are regarded as the highest-order association cortices. The hippocampus has been proposed to store "cognitive maps" of external environments, and the prefrontal cortex is known to be involved in the planning of behavior, among other functions. Considering the prominent functional roles played by these structures, it is not surprising to find direct monosynaptic projections from the hippocampus to the prefrontal cortex. Rhythmic stimulation of this projection patterned after the hippocampal EEG theta rhythm induced stable long-term potentiation of field potentials in the prefrontal cortex. Comparison of behavioral correlates of hippocampal and prefrontal cortical neurons during an a-arm radial maze, working memory task shows a striking contrast. Hippocampal neurons exhibit clear place-specific firing patterns, whereas prefrontal cortical neurons do not show spatial selectivity, but are correlated to different stages of the behavioral task. These data lead to the hypothesis that the role of hippocampal projection to the prefrontal cortex is not to impose spatial representations upon prefrontal activity, but to provide a mechanism for learning the spatial context in which particular behaviors are appropriate.propriate.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2003.09a
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• pp.75-75
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• 2003

Purpose: To investigate whether or not acupuncture of GB34 produces a significant response of the modulation of somatomotor areas by functional magnetic resonance imaging (fMRI) study. Methods: The acupoint, GB34, located in the back of the knee, is known to be effective in recovering motor function after stroke. Using 3T MRI scanner, functional MR imaging of the whole brain was performed in 12 normal healthy subjects during two stimulation paradigms; acupuncture manipulation on GB 34 and sham points. This study investigates the activation of the motor cortex elicited by a soft and an intensified stimulation of GB 34. Three different paradigms were carried out to detect any possible modulation of the Blood Oxygenation Level Dependent (BOLD) response in the somatomortor area to motor stimulation through acupuncture. Results: Group analysis from seven individuals showed that bilateral sensorimotor areas (BA 3,4,6 and 7) showed stimulation related BOLD signal contrast of approximately 6% whereas very few areas were activated when sham stimulation is given. Conclusions: The present study shows that acupuncture fMRI study can be safely conducted in 3T MRI environment, and acupuncture stimulation in GB34 modulates the cortical activities of the soma- to motor area in human. The present findings may shed light on the CNS mechanism of motor function by acupuncture and form a basis for future investigations of motor modulation circuits in the stroke patients. Acknowledgement: This study was supported by a grant of the Mid and Long Term Nuclear RID Plan Program, Ministry of Science and Technology, Republic of Korea.