• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.1
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• pp.7-14
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• 2000

Inhibitory cells are critically involved in shaping normal hippocampal function and are thought to be important elements in the development of hippocampal pathologies. The present study was carried out in hippocampal CA1 area in vivo to compare with hippocampal slice studies. Intracellular and extracellular recordings with or without bicuculline electrodes were obtained in the intact brain of anesthetized rats, and cells were intracellularty labelled with neurobiotin. Electrical stimulation of fimbria-fornix resulted in an initial short-latency population spike. In the presence of $10{\mu}M$ bicuculline, orthodromic stimulation resulted in bursts of population spikes. The amplitude of population spikes in the CA1 region increased with stimulus intensity, as did the number of population spikes when the field recording electrode contained $10{\mu}M$ bicuculline. We measured the level of excitability in the CA1 area, using a paired-pulse stimulus paradigm to evoke population spikes. Population spikes showed strong paired-pulse inhibition at short interstimulus intervals. Burst afterdischarges up to 400 ms were observed after paired-pulse stimulus. These result suggest that hippocampal CA1 inhibitory interneurons can affect the excitability of pyramidal neurons that can not be appreciated in conventional in vitro preparation.

• Therapeutic Science for Rehabilitation
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• v.3 no.2
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• pp.5-48
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• 2014

Introduction : One of the important domains in OT is performance skills which include sensory perceptual skills, motor and praxis skills, emotional regulation skills, cognitive skills, and communication/social skills. All of these skills are support ed by integrated neurological processes. Body : Stereology robust tool when employed to investigate morphological changes in neurons, cortex area, and specific parts of brain involved in special brain function. Stereology is an interdisciplinary field focused or analyzing biological tissue with the three-dimensional interpretation of planer sections by using estimating method and mathematically unbiased sampling. With the unbiased stereological method based on probability theory, researchers can estimate morphological and anatomical changes in biological reference areas accurately and efficiently. Changes in anatomical and cytoarchitectural parameters, such as volume, number, and length, affect specific brain function related to the brain area. Occupational therapists provide treatment to improve functions for participation of occupation in neurological disorder. The functional improvements in neurological disorder reflect neurobiological changes because functional difficulties, such as motor cognitive disorder, are due to neurological disturbances. Thus, combination of two kinds of evidence, neurological changes and functional improvement, provide fundamental evidence for OT intervention in neurological disorder. Even though most of stereological studies are in animal model and in postmortem human because of practical and ethical issues, stereology provides fundamental knowledge to support OT theory and practice. Conclusion : Therefore, stereology informs translation from neuroscience to OT based on structure-function relationship in performance skills and experience-dependent neural plasticity.

• Development and Reproduction
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• v.4 no.1
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• pp.95-100
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• 2000

A large number of man-made chemicals that have been released into the environment have the potential to disrupt the endocrine system of animals and humans. There is a critical developmental period during which sexual brain differentiation proceeds irreversibly under the influence of gonadal hormone. Recently we identified KAP3 gene expressed during the critical period of rat brain sexual differentiation. KAP3 functions as a microtubule-based motor that transports membranous organelles anterogradely in cells, including neurons. In the present study, we aimed to investigate the effect of endocrine disrupter, Dichlorodiphenyl trichloroethane (DDT), on the KAP3 gene expression during critical period of rat brain development. Maternal exposure to DDT increased the level of KAP3 mRNA in male and female fetus brains when examined on the gestational day 17 (GDl7). In postnatal day 6, DDT suppressed the expression of KAP3 gene in male and female rat brain. Also, the body weight and fertilization rate were decreased in the DDT exposured rats. These results showed that endocrine disrupter, DDT, can affect the transcriptional level of brain sexual differentiation related gene, KAP3, in the prenatal and the neonatal rat brain and that maternal exposure to endocrine disruptors may lead to a toxic response in embryonic differentiation of brain. And so KAP3 gene may be used a gene maker to analyse the molecular mechanism for toxic response in animal nerve tissues exposed to endocrine disruptors.

• Journal of the Korean Geotechnical Society
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• v.18 no.5
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• pp.37-42
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• 2002

Artificial neural networks are efficient computing techniques that are widely used to solve complex problems in many fields. In this paper a liquefaction potential was estimated by using a back propagation neural network model applicated to cyclic triaxial test data, soil parameters and site investigation data. Training and testing of the network were based on a database of 43 cyclic triaxial test data from 00 sites. The neural networks are trained by modifying the weights of the neurons in response to the errors between the actual output values and the target output value. Training was done iteratively until the average sum squared errors over all the training patterns were minimized. This generally occurred after about 15,000 cycles of training. The accuracy from 72% to 98% was shown for the model equipped with two hidden layers and ten input variables. Important effective input variables have been identified as the NOC,$D_10$ and (N$_1$)$_60$. The study showed that the neural network model predicted a CSR(Cyclic shear stress Ratio) of silty-sand reasonably well. Analyzed results indicate that the neural-network model is more reliable than simplified method using N value of SPT.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.12 no.1
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• pp.46-54
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• 2001

Background and Objectives : Nitric oxide(NO) is a short-lived molecule with messenger and cytotoxic functions in nervous, cardiovascular, and immune systems. Among the three distinct NOS isoforms, the neuronal isoform is expressed in small, discrete neuronal populations of CNS and PNS. Axonal injury in adult animals results in a dramatic NOS up-regulation in many types of central and peripheral neurons which normally lack the enzyme or express it only at very low levels. In previous study, we confirmed the efficacy of PEMS on the early functional recovery in rats with surgically transected and reanastomosed recurrent laryngeal nerve. Therefore, after we obtained functionally recovered rats using PEMS in this study, we studied to evaluate the expression of nNOS through the analysis of the difference between functional recovery group and non-recovery group in the recurrent laryngeal nerve. Materials and Method : Using 84 healthy male Sprague-Dawley rats, transections and primary anastomosis were performed on their left recurrent laryngeal nerves. Rats were then randomly assigned to 2 groups. The rats in group A(n=42) received PEMS by placing them in custom cages equipped with Helm-holz coils(3 hr/day, 5 days/wk, for 12 wk). The rats in group B(n=42) were handled the same way as the group A, except that they did not receive PEMS. Laryngovideoendoscopy was performed before and after surgery and followed up weekly. Laryngeal EMG was obtained in both PCA and TA muscles. Immunohistochemisty staining using monoclonal anti-neuronal nitric oxide synthase(nNOS) antibody was performed to detect nNOS in recurrent laryngeal nerve and nodose ganglion. Results : 20 rats(63%) in group A and 5 rats(17%) in the group B showed recovery of vocal fo1d motion. The number of NOS-positive cells was increased in functionally-recovered rats. NOS-staining intensity was reduced 12 weeks after nerve injury. The difference between PEMS group and non-stimulated group was not found. Conclusion : This study shows that nNOS may exert a beneficial effect on nerve regeneration and functional repair.

• Journal of the Korean earth science society
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• v.28 no.2
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• pp.214-226
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• 2007

Because precipitation is influenced by various atmospheric variables, it is highly nonlinear. Although precipitation predicted by a dynamic model can be corrected by using a nonlinear Artificial Neural Network, this approach has limits such as choices of the initial weight, local minima and the number of neurons, etc. In the present paper, we correct simulated precipitation by using a multiple linear regression (MLR) method, which is simple and widely used. First of all, Ensemble hindcast is conducted by the PNU/CME Coupled General Circulation Model (CGCM) (Park and Ahn, 2004) for the period from April to August in 1979-2005. MLR is applied to precipitation simulated by PNU/CME CGCM for the months of June (lead 2), July (lead 3), August (lead 4) and seasonal mean JJA (from June to August) of the Northeast Asian region including the Korean Peninsula $(110^{\circ}-145^{\circ}E,\;25-55^{\circ}N)$. We build the MLR model using a linear relationship between observed precipitation and the hindcasted results from the PNU/CME CGCM. The predictor variables selected from CGCM are precipitation, 500 hPa vertical velocity, 200 hPa divergence, surface air temperature and others. After performing a leave-oneout cross validation, the results are compared with the PNU/CME CGCM's. The results including Heidke skill scores demonstrate that the MLR corrected results have better forecasts than the direct CGCM result for rainfall.

• Journal of Radiation Protection and Research
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• v.40 no.1
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• pp.55-64
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• 2015

Dose calculations which are a crucial requirement for radiotherapy treatment planning systems require accuracy and rapid calculations. The conventional radiotherapy treatment planning dose algorithms are rapid but lack precision. Monte Carlo methods are time consuming but the most accurate. The new combined system that Monte Carlo methods calculate part of interesting domain and the rest is calculated by neural can calculate the dose distribution rapidly and accurately. The preliminary study showed that neural networks can map functions which contain discontinuous points and inflection points which the dose distributions in inhomogeneous media also have. Performance results between scaled conjugated gradient algorithm and Levenberg-Marquardt algorithm which are used for training the neural network with a different number of neurons were compared. Finally, the dose distributions of homogeneous phantom calculated by a commercialized treatment planning system were used as training data of the neural network. In the case of homogeneous phantom;the mean squared error of percent depth dose was 0.00214. Further works are programmed to develop the neural network model for 3-dimensinal dose calculations in homogeneous phantoms and inhomogeneous phantoms.

• Journal of Life Science
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• v.14 no.6 s.67
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• pp.975-985
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• 2004

This study attempts to investigate the developmental alterations of rat cerebral cortex, and the effects of EGEE on the developmental cerebral cortex in the prenatal, postnatal and adults were examined by morphological methods and H-E staining was used for the histological changes. In the case of injection of EGEE, at 14 day of fetal phase, parietal cortex was thickest $(95{\pm}12.7\;{\mu}m)$ but, it was thinner than in the control group $(102{\pm}14.0\;{\mu}m)$ and, occipital cortex $(57{\pm}10.5\;{\mu}m)$ compared with other cortexes was the thinnest in fetal phase. In the suckling phase, each cortex grew thick quickly but, after weanning phase, the growth of the cortex slowed and the thickness of cortex was similar to that of cortex in the adult phase. At 105 day after birth, the parietal cortex was thickest $(934{\pm}21.6\;{\mu}m)$ but, decreased compared with control group $(1113{\pm}19.0\;{\mu}m)$. When EGEE was injected in intraperitoneal of rat, the number of neuroblasts per unit area was largest $(207.7{\pm}11.4/10^{-2}\;mm$ at the mantle layer of parietal cortex at 14 day of fetal phase but, decreased compared with control group $(224.2{\pm}13.8/10^{-2}\;mm$ , and the size was largest $(7.5{\pm}1.3\;{\mu}m)$ at the ependymal cell layer of occipital cortex at 3 day after birth but, decreased compared with control group $(9.0{\pm}1.2\;{\mu}m)$. Simillar to control group, the number of granular cells and pyramidal cells were largest at the II and III layer of parietal cortex, but decreased during developmental phase. The size was largest at the IV and V layer of occipital cortex but it was decreased compared with control group. When EGEE was injected in intraperitoneal of rat, the cerebral cortex from fetal phase to 3 day after birth has differentiated into the 3 layers; ependymal, mantle and marginal layer, but empty cisternaes or vacoules in the cerebral cortexes and the condensed phases of neuroblasts were appeared. From 5 day after birth, it has differentiated into the 4 layers; molecular, external granular, mixed layer of internal granular, external and internal pyramidal cells and multiformal layer but, empty cisternaes or vacoules in the granular and pyramidal cell layers were appeared and the number per unit area of neuron was decreased. In the cerebral cortex of the weaning and adult phases, division of cell layers was not clear and empty cisternae was formed in the cortex with the cells in external granular and pyramidal cell layers, was magnified or condensed around blood vessels of neurons.

• The Journal of Korean Academy of Sensory Integration
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• v.9 no.2
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• pp.51-60
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• 2011

Objective : The characteristics of physiological responses of ADHD children to sensory stimulation were examined by types of sensory stimulation, measurement tools, and responses. In addition the behavioral characteristics were examined by analyzing items of common problems according to the measuring tool, frequency, and measurement tools. Methods : A systematic review methods were used. Papers published in the Journal between January, 1990 and December 31, 2011 were searched through Riss4U, MEDLINE /PubMed, CINAH. The main terms searched were "ADHD, Children, Sensory processing, Sensory integration, SP, SSP, SOR, TIE, CSP, SEP, EDR", and 15 papers were analyzed. Results : 1. The number of studies on physiological responses of children with ADHD to sensory stimulation was five (33.33 percent), the number of studies on behavioral responses was ten(66.67%), and the number of studies combined the two kinds of study was two (13.33%), where a total of 15 (100%) papers were analyzed. 2. In five studies on the physiological response, there were three studies using tactile and proprioceptive stimulations and two studies using olfactory, auditory, visual, tactile, and vestibular sensories. 3. In ten studies on the behavioral responses, there were five studies using SP, three studies using SSP, two studies using SOR, one study using TIE, and one study using CSP. Conclusion : In the characteristics of physiological responses of children with ADHD children to sensory stimulation, there was in the action potential of the cells in hand region of the primary sensorimotor cortex neurons. It was analyzed that there was an initial state and it appeared show a obvious and fast habituation in the later state; the time of recovery seemed to have many non-specific responses. In the characteristics of behavioral responses, there were inattention / distraction, vestibular processing, sensory processing related to endurance / tone, modulation of sensory input affecting emotional responses, low energy/weak.

• Clinical and Experimental Pediatrics
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• v.52 no.12
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• pp.1337-1347
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• 2009

Purpose:Taurine (2-aminoethanesulfonic acid) is a simple sulfur-containing amino acid. It is abundantly present in tissues such as brain, retina, heart, and skeletal muscles. Current studies have demonstrated the neuroprotective effects of taurine, but limited data are available for such effects during neonatal period. The aim of this study was to determine whether taurine could reduce hypoxic-ischemic (HI) cerebral injury via anti-apoptosis mechanism. Methods:Embryonic cortical neurons isolated from Sprague-Dawley (SD) rats at 18 days gestation were cultured in vitro. The cells were divided into hypoxia group, taurine-treated group before hypoxic insult, and taurine-treated group after HI insult. In the in vivo model, left carotid artery ligation was performed in 7-day-old SD rat pups. The pups were exposed to hypoxia, administered an injection of 30 mg/kg of taurine, and killed at 1 day, 3 days, 1 week, 2 weeks, and 4 weeks after the hypoxic insult. We compared the expressions of Bcl-2, Bax, and caspase-3 among the 3 groups by using real- time polymerase chain reaction (PCR) and western blotting. Results:The cells in the taurine-treated group before hypoxic insult, although similar in appearance to those in the normoxia group, were lesser in number. In the taurine-treated group, Bcl-2 expression increased, whereas Bax and caspase-3 expressions reduced. Conclusion:Taurine exerts neuroprotective effects onperinatal HI brain injury due to its anti-apoptotic effect. The neuroprotective effect was maximal at 1-2 weeks after the hypoxic injury.