• Molecules and Cells
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• v.37 no.7
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• pp.511-517
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• 2014

MicroRNAs are non-coding short (~23 nucleotides) RNAs that mediate post-transcriptional regulation through sequence-specific gene silencing. The role of miRNAs in neuronal development, synapse formation and synaptic plasticity has been highlighted. However, the role of neuronal activity on miRNA regulation has been less focused. Neuronal activity-dependent regulation of miRNA may finetune gene expression in response to synaptic plasticity and memory formation. Here, we provide an overview of miRNA regulation by neuronal activity including high-throughput screening studies. We also discuss the possible molecular mechanisms of activity-dependent induction and turnover of miRNAs.

• Journal of Biomedical Engineering Research
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• v.29 no.5
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• pp.355-363
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• 2008

In order to extract only the alpha activity related signals from EEG recordings, we have applied Constrained Independent Component Analysis (cICA), a new extension of ICA in which some a priori knowledge of the alpha activity is utilized to extract only desired components. Its extraction (or filtering) performance has been compared to that of the conventional band-pass filtering via the scalp alpha power maps and cortical source maps of the alpha activity. Our results demonstrate that the alpha power maps and cortical source maps from the cICA-extracted alpha signals reveal more focalized alpha generating regions of the brain than those from the band-pass filtered alpha EEG signals. Furthermore they match more closely the activated regions of the brain mapped using fMRI, validating our results. We believe that the cICA-based filtering approach of EEG signals is a more effective means of extracting a specific brain activity reflected in EEG signals that will result in more accurate source localization or imaging maps.

• Journal of Korean Neurosurgical Society
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• v.65 no.6
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• pp.861-867
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• 2022

Objective : High-dose radiation is well known to induce and modulate the immune system. This study was performed to evaluate the correlation between clinical outcomes and changes in natural killer cell activity (NKA) after Gamma Knife Radiosurgery (GKS) in patients with brain cancer. Methods : We performed an open-label, prospective, cross-sectional study of 38 patients who were treated with GKS for brain tumors, including metastatic and benign brain tumors. All of the patients underwent GKS, and blood samples were collected before and after GKS. NKA was measured using an enzyme-linked immunosorbent assay kit, to measure interferon-gamma (IFNγ) secreted by ex vivo-stimulated NK cells from whole blood. We explored the correlations between NK cell-produced IFNγ (NKA-IFNγ) levels and clinical parameters of patients who were treated with GKS for brain tumors. Results : NKA-IFNγ levels were decreased in metastatic brain tumor patients compared to those with benign brain tumors (p<0.0001). All the patients who used steroid treatment to reduce brain swelling after GKS had an NKA-IFNγ level of zero except one patient. High NKA-IFNγ levels were not associated with a rapid decrease in brain metastasis and did not increase after GKS. Conclusion : The activity of NK cells in metastatic brain tumors decreased more than that in benign brain tumors after GKS.

• BMB Reports
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• v.46 no.2
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• pp.103-106
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• 2013

Phosphoinositide 3-kinases (PI3Ks) play key roles in synaptic plasticity and cognitive functions in the brain. We recently found that genetic deletion of $PI3K{\gamma}$, the only known member of class IB PI3Ks, results in impaired N-methyl-D-aspartate receptor-dependent long-term depression (NMDAR-LTD) in the hippocampus. The activity of RalA, a small GTP-binding protein, increases following NMDAR-LTD inducing stimuli, and this increase in RalA activity is essential for inducing NMDAR-LTD. We found that RalA activity increased significantly in $PI3K{\gamma}$ knockout mice. Furthermore, NMDAR-LTD-inducing stimuli did not increase RalA activity in $PI3K{\gamma}$ knockout mice. These results suggest that constitutively increased RalA activity occludes further increases in RalA activity during induction of LTD, causing impaired NMDAR-LTD. We propose that $PI3K{\gamma}$ regulates the activity of RalA, which is one of the molecular mechanisms inducing NMDAR-dependent LTD.

• Korean Journal of Clinical Laboratory Science
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• v.37 no.2
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• pp.123-128
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• 2005

Magnetoencephalography (MEG) is the measurement of the magnetic fields produced by electrical activity in the brain, usually conducted externally, using extremely sensitive devices such as Superconducting Quantum Interference Device (SQUID). MEG needs complex and expensive measurement settings. Because the magnetic signals emitted by the brain are on the order of a few femtoteslas (1 fT = 10-15T), shielding from external magnetic signals, including the Earth's magnetic field, is necessary. An appropriate magnetically shielded room is very expensive, and constitutes the bulk of the expense of an MEG system. MEG is a relatively new technique that promises good spatial resolution and extremely high temporal resolution, thus complementing other brain activity measurement techniques such as electroencephalography (EEG), positron emission tomography (PET), single-photon emission computed tomography (SPECT) and functional magnetic resonance imaging (fMRI). MEG combines functional information from magnetic field recordings with structural information from MRI. The clinical uses of MEG are in detecting and localizing epileptic form spiking activity in patients with epilepsy, and in localizing eloquent cortex for surgical planning in patients with brain tumors. Magnetoencephalography may be used alone or together with electroencephalography, for the measurement of spontaneous or evoked activity, and for research or clinical purposes.

• Journal of Physiology & Pathology in Korean Medicine
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• v.27 no.1
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• pp.49-56
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• 2013

Chrysanthemum boreale(CB) is an oriental medicinal herb which has been used traditionally for the treatment of various brain disease including headache, dizziness and sedation. In order to examine the mechanism of anti-parkinsonism effect, water extract of CB(100 mg and 200 mg/kg of b.w.) were administered orally during 28 days in MPTP-induced parkisonism mice model. Water extract of CB increased the motor activities. CB did not affect total MAO and MAO-B activity in the brain of MPTP-induced mice. CB significantly increased the concentration of lipid peroxidation in the mid brain. Also, CB significantly increased antioxidant enzyme including were SOD, catalase and glutathione peroxidase in the mid brain activity. CB significantly increased the concentration of dopamine and homovanillic acid in the brain. These results suggest that the anti-parkinsonism effect of CB is possibly due to the antioxidative effects at mid brain in MPTP-induced animal model.

• Journal of Physiology & Pathology in Korean Medicine
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• v.16 no.3
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• pp.567-571
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• 2002

In order to prove the sedative, anticonvulsive effects of Incenses and to identify the effect of this medicine to cerebral glutamic acid and GABA density in experimental animal. we used Incense which was made of traditional herb medicines. We also examined what kind of material is to be involved in biosynthesis of these elements. In addition we experimented to find out synthesis of active GABA-T. Incenses were inhaled 8 hours a day for 4 weeks to mice. Finally we have following results. On the convulsion induced by pentylenetetrazole(PTZ), Incenses showed significant anticonvulsive effect. Density of glutamic acid in brain was significantly decreased. On the contrary, density of GABA was significantly increased. The Activity of GABA- T in brain was significantly reduced. The quantity of lipid peroxide in the brain was significantly decreased. Activity of xanthine oxidase and aldehyde oxidase were significantly reduced in brain. From the above results, we confirmed that Incenses decreased the density of glutamic acid, increased GABA density and decreased the activity of GABA- T in brain. For the convulsion which was induced by PTZ, Incenses showed significant anticonvulsive effect. With this we can recognize that Incenses had ability to control the quantity of lipid peroxide in brain. In the conclusion, Incenses has significant anticonvulsive effect, so I strongly recommend to prescribe Incenses to treat convulsive disorder like epilepsy.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2002.05a
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• pp.270-273
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• 2002

The purpose of our study is to clarify about the influence that the visual information gives to the brain activities when pressure exerted the abdomen by waist belts. The visual information means that the some different visual information is inputted it, and the brain activity is evaluated by Electroencephalogram(EEG) measurements. At the same time, we carried out the sensory tests and verified about the relations between the psychological stress and the brain activities. There was a difference in change in the power of the $alpha$ wave with the eyes opened between man and woman. from the result of the sensory test, in the case of under the condition in the darkness with the eyes opened, there was no change in the a wave with before the pressure and after the pressure. In the other cases, $alpha$ wave changed in the same way with before the pressure and after the pressure. In the case of the visible and the invisible in pressure place, $alpha$ wave changed in the same way with before the pressure and after the pressure, but there was a difference in value. From the above, it isn't recognized that the visual information is influencing a pressure sense but some influences are given to it to the brain activities.

• Journal of Radiation Industry
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• v.4 no.3
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• pp.203-207
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• 2010

Radiation-induced late injury to normal tissue is a primary area of radiation biology research. The present study was undertaken to investigate whether the late effect of the ionizing radiation appears as an age-related oxidative status in the brain. Three groups of 4-month old C57BL/6 mice that were exposed to $^{137}Cs$ ${\gamma}-rays$ at a single dose (5 Gy) or fractionated doses ($1Gy{\times}5times$, or $0.2Gy{\times}25times$) at 2 months old were investigated for the oxidative status of their brains with both young (2-month) and old (24-month) mice. A significant (p<0.05) decrease in superoxide dismutase (SOD) activity was observed in old mice brains compared with that of the young mice. malondialdehyde (MDA) content was significantly (p<0.05) increased in the old mice brain. However, any significant difference in SOD activity and MDA contents of the irradiated brain was not observed compared to age-matched control group mice. SOD activity and MDA content were observed within good parameters of brain aging and there were no late effects on the age-related oxidative level in the ${\gamma}-ray$ irradiated mice brains.

• Toxicological Research
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• v.22 no.3
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• pp.245-251
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• 2006

Nitric oxide(nitrogen monoxide, NO) plays important physiological roles, but excessive generation can be toxic. NO is present in cigarette smoke at up to 1,000 ppm, and probably represents one of the greatest exogenous sources of NO to which humans are exposed. We investigated whether cigarette smoking reduces the production of endogenous NO and whether it influences the action of lipopolysaccharide(LPS) to induce nitric oxide synthase activity in mouse brain. Mice(C57BL6/J) were exposed to cigarette smoke for 8 weeks. LPS was injected intraperitoneally in single or combination with the exposure to cigarette smoke. Six hours after the injection of LPS, mice were sacrificed and sera and brains were collected. Serum concentrations of nitrate and nitrite were not charged by 4-week smoke exposure, but were significantly increased by 6 and 8 weeks of smoke exposure. Interestingly, cigarette smoke reduced the elevation in serum nitrate and nitrite concentrations produced by LPS after 4-week smoking exposure. NO synthase(NOS) activity in brain was upregulated by LPS-administration. However, cigarette smoke exposure remarkably and consistently decreased the LPS-induced activity in mouse brain. This result suggests that cigarette smoking may affect against overproduction of the endogenous NO by LPS through the inhibition of NOS activity induced by LPS in brain or by modulation of the LPS action for the induction of NOS activity. We also suggest the possibility that the exogenous NO evolved in cigarette smoke enables feedback inhibition of NOS activity or other possibility that it attenuates the toxicity of endotoxin LPS in vivo by unknown mechanisms, which should be further studied.