• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2005.11a
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• pp.381-384
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• 2005

현존하는 정보처리 시스템 중에서 가장 뛰어난 성능을 지니고 있는 것은 인간의 두뇌라고 할 수 있다. 두뇌의 정보처리 메커니즘을 보다 정확하게 구현할 수 있는 시스템은 입력에 대한 정확한 인지 능력, 상황 판단 능력, 학습 및 추론 능력, 출력의 결정 능력 등의 성능 구현은 물론이며, 감정과 비교될 수 있는 시스템의 상태를 평가하여 판단 및 결정에 적용함으로써 매우 뛰어난 지능형 시스템이 쥘 수 있다. 이러한 뇌 정보처리 시스템의 구현에 앞서 본 논문에서는 생물학적인 대뇌 피질의 구조를 살피고 정보의 처리 영역을 고찰하고 정보의 흐름을 소개하였으며 이를 바탕으로 뇌 정보처리 메커니즘을 공학적인 측면에서 해석해 보았다. 특히, 뇌 영역의 기능 및 구조적인 특징, 정보의 처리과정 등을 공학적으로 해석하였으며 이는 뇌의 기능을 모방한 공학적인 모델을 구현하는데 있어서 기초가 될 것이다.

• Journal of Biomedical Engineering Research
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• v.22 no.2
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• pp.145-150
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• 2001

대뇌 피질에 삽입하여 깊이에 따라 신경 신호를 기록하기 위한 탐침형 반도체 미세전극 어레이(depth-type silicon microelectrode array, 일명 SNU probe)를 제작하였다. 붕소를 확산시켜 생성된 고농도 p-type doping된 p＋ 영역을 습식식각 정지점으로 사용하는 기존의 방법과 달리 실리콘 웨이퍼의 앞면을 건식식각하여 원하는 탐침 두께만큼의 깊이로 트렌치(trench)를 형성한 후 뒷면을 습식식각하는 방법으로 탐침 형태의 미세 구조를 만들었다. 제작된 반도체 미세전극 어레이의 탐침 두께는 30 $\mu\textrm{m}$이며 실리콘 건식식각을 위한 마스크로 6 $\mu\textrm{m}$ 두께의 LTO(low temperature oxide)를 사용하였다. 탐침의 두께는 개발된 본 공정을 이용해서 5~90 $\mu\textrm{m}$ 범위까지 쉽게 조절할 수 있었다. 탐침의 두께를 보다 쉽게 조절할 수 있게 됨에 따라 여러 신경조직에 필요한 다양한 구조의 반도체 미세전극 어레이를 개발할 수 있게 되었다. 본 공정을 이용해서 개발된 4채널 SUN probe를 사용하여 흰쥐의 제1차 체감각 피질에서 4채널 신경 신호를 동시에 기록하였으며, 전기적 특성검사에서 기존의 탐침형 반도체 미세전극, 텅스텐 전극과 대등하거나 우수한 신호대 잡음비(signal to noise ratio, SNR)특성을 가짐을 확인하였다.

• Applied Microscopy
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• v.35 no.3
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• pp.135-152
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• 2005

Prefrontal cortex is a psychological and metaphysical cortex, which deals with feeling, memory, planning, attention, personality, etc. And it also integrates above-mentioned events with motor control and locomotor activities. Prefrontal cortex works as a highest CNS center, since the above mentioned functions are very important for one's successful life, and further more they are upgraded every moments through memory and learning. Many of these highest functions are supposed to be generated via forebrain basal nuclei (caudate nucleus, fundus striati nucleus, accumbens septi nucleus, septal nucleus, etc.). In this experiment, prefrontal efferent terminals within basal forebrain nuclei were ultrastructurally studied. Spraque Dawley rats, weighing $250{\sim}300g$ each, were anesthetized and their heads were fixed on the stereotaxic apparatus (experimental model, David Kopf Co.). Rats were incised their scalp, perforated a 3mm-wide hole on the right side of skull at the 11mm anterior point from the frontal O point (Ref. 13, Fig. 1), suctioned out the prefrontal cortex including cortex of the frontal pole, with suction instrument. Two days following the operations, small tissue blocks of basal forebrain nuclei were punched out, fixed in 1% glutaraldehyde-1% paraformaldehyde solution followed by 2% osmium tetroxide solutions. Ultrathin sections were stained with 1% borax-toluidin blue solution, and the stained sections were obserbed with an electron microscope. Degenerating axon terminals were found within all the basal forbrain nuclei. Numbers of degenerated terminals were largest in the caudate nucleus, next in order, in the fundus striati nucleus, in the accumbens septi nucleus, and the least in the septal nucleus. Only axospinous terminals were degenerated within the caudate nucleus and the fundus striati nucleus, and they showed the characters of striatal motor control system. Axodendritic and axospinous terminals were degenerated within the accumbens septi nucleus and the lateral septal nucleus, and they showed the characters of visceral limbic system. Prefrontal role in integrating the limbic system with the striatal system, en route basal forebrain nuclei, was discussed.

• Korean Journal of Cognitive Science
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• v.28 no.4
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• pp.267-297
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• 2017

The anatomical structure of the brain reflects a great amount of information about an individual's cognitive ability. The present study reviewed research on developmental changes in brain structure in relation to biological maturation and intellectual growth focusing on children and adolescents. The purpose of the present study was to achieve an understanding of how children and adolescents' brain matures with development and also to examine whether individual differences in intelligence influences the development of brain structure. The first section introduces methods of measurement and analysis of brain structure, such as voxel-based morphometry and structural covariance. The second section reviews studies on the biological maturation of the brain and variables that influence brain development such as sex, environmental factors, and mental disorders, etc. The third section introduces the Parieto-Frontal Integration Theory of intelligence and reviews studies on the association between intelligence and developmental changes of the brain, including changes in structural covariance and functional connectivity. We conclude with a discussion on educational/clinical implications of this work and directions for future studies.

• Applied Microscopy
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• v.25 no.1
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• pp.65-74
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• 1995

An immunocytochemical study of GABA-positive neuronal elements was performed at the electron microscopic level to examine subcellular distribution of the inhibitory neurotransmitter in the dog basilar pons. Electron-dense reaction product was observed in neuronal somata and dendritic processes. One or more unlabeled axon terminals made asymmetric synaptic contacts with these GABAergic somatic and dendritic profiles. A large number of GABA-positive axon terminals were also observed. They made symmetric as well as asymmetric synaptic contacts with unlabeled dendritic profiles. In axo-axonic synapses, postsynaptic axon-like processes were consistently GABA-immunoreactive. These observations suggest that the inhibitory local circuit neurons in the dog basilar pons play a major role in cerebro-ponto-cerebellar circuitry by integrating various afferent inputs and conveying them into the cerebellar cortex and the deep cerebellar nuclei.

• Applied Microscopy
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• v.28 no.4
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• pp.563-575
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• 1998

To investigate the changes during the differentiation of the cerebral neurons of chick embryo of tne embryogenic day (ED) 7 and 8, the ultrastructural changes in the cerebral neurons, the activity of dehydronases (LDH, MDH and SDH), protein expression profile and adenosine triphosphate concentration were analyzed. In ED 7 chick embryos, relatively large nucleus, centrally located nucleolus, evenly spread chromatin over nucleoplasm, and prominent nuclear envelope were observed. Oval-shaped mitochondria with well-developed cristae were present over entire cytoplasm. In ED 8 chick embryos, evenly spread chromatin over nucleoplasm, and prominent nuclear envelope were observed. In the cytoplasm, well-developed rough endoplasmic reticulum and Golgi complex were observed. In ED 7 chick embryos and ED 8 chick embryos, 31 polypeptide bands and 34 polypeptide bands were observed, respectively. The activities of dehydrogenases were lower in ED 7 chick embryos than in ED 8 chick embryos. LDH activity was 8.16 (ED 7) and 9.28 (ED 8), MDH activity was 7.98 (ED 7) and 10.10 (ED 8), and SDH activity was 5.49 (ED 7) and 7.14 (ED 8) respectively. The ATP concentration remained unchanged over ED 7 and 8.

• Korean Journal of Animal Reproduction
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• v.23 no.1
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• pp.69-73
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• 1999

A calf with derodidymus was delivered from a 3-year old Korean-native cow with abortion last ime at Jangheong area in Chonnam Province. The anomaly with body weight of 35 kg was born t the normal time of parturition. During the parturition, however, the calf with twin head was onfirmed and the complete amputation between fore and hind limb was inevitably carried out or safety of the dam. The calf had normal skeleton and extremities but had two heads and cervical vertebrae divided from upper thoracic part. At necropsy, there were found totally 3 pairs of ore limbs including two pairs of hypoplastic ones hided in the thoracic limb and also found one air of sternum. One head had incomplete torsion or unilateral hypoplasia of mandible with artly hypoplastic skull. There were marked fusion and torsion from cervical to 3rd thoracic vertebra. No abnormality was found on all organs in the pleural and abdominal cavities except a rectal stricture formed at 5 cm away from the atresia ani.

• The Korean Journal of Nuclear Medicine
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• v.32 no.3
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• pp.238-249
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• 1998

Purpose: To localize and compare the neural basis of verbal and visual human working memory, we performed functional activation study using $H_2^{15}O$ PET. Materials and Methods: Repeated $H_2^{15}O$ PET scans with one control and three different activation tasks were performed on six right-handed normal volunteers. Each activation task was composed of 13 match-ing trials. On each trial, four targets, a fixation dot and a probe were presented sequentially and subject's task was to press a response button to indicate whether or not the probe was one of the previous targets. Short meaningful Korean words, simple drawings and monochromic pictures of human faces were used as matching objects for verbal or visual memory. All the images were spatially normalized and the differences between control and activation states were statistically analyzed using SPM96. Results: Statistical analysis of verbal memory activation with short words showed activation in the left Broca's area, promoter cortex, cerebellum and right cingulate gyrus. In verbal memory with simple drawings, activation was shown in the larger regions including where activated with short words and left superior temporal cortex, basal ganglia, thalamus, prefrontal cortex, anterior portion of right superior temporal gyrus and right infero-lateral frontal cortex. On the other hand, the visual memory task activated predominantly right-sided structures, especially inferior frontal cortex, supplementary motor cortex and superior parietal cortex. Conclusion: The results are consistent with the hypothesis of the laterality and dissociation of the verbal and visual working memory from the invasive electrophysiological studies and emphasize the pivotal role of frontal cortex and cingulate gyrus in working memory system.

• Investigative Magnetic Resonance Imaging
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• v.15 no.2
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• pp.110-122
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• 2011

Purpose : The purpose of this study is to establish the method generating human brain anatomical connectivity from Korean children and evaluating the network topological properties using small-world network analysis. Materials and Methods : Using diffusion tensor images (DTI) and parcellation maps of structural MRIs acquired from twelve healthy Korean children, we generated a brain structural connectivity matrix for individual. We applied one sample t-test to the connectivity maps to derive a representative anatomical connectivity for the group. By spatially normalizing the white matter bundles of participants into a template standard space, we obtained the anatomical brain network model. Network properties including clustering coefficient, characteristic path length, and global/local efficiency were also calculated. Results : We found that the structural connectivity of Korean children group preserves the small-world properties. The anatomical connectivity map obtained in this study showed that children group had higher intra-hemispheric connectivity than inter-hemispheric connectivity. We also observed that the neural connectivity of the group is high between brain stem and motorsensory areas. Conclusion : We suggested a method to examine the anatomical brain network of Korean children group. The proposed method can be used to evaluate the efficiency of anatomical brain networks in people with disease.

• Korean Journal of Veterinary Research
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• v.33 no.3
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• pp.465-469
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• 1993

This paper dealt with the histopathological findings on the natural cysticercosis in pigs. Three cases of porcine cysticercosis, which had been kept in the Department of Veterinary Medicine, Cheju. University more than ten years, were histopathologically examined in order to see the host reaction to the parasite. Capsules containing scolex were mainly found in the fascia of skeletal muscle, heart, and brains. Microscopically, cysticerci in the epicardium and the fascia of skeletal muscles were encapsulated with fibroblasts and collagen fibers. Around capsules, there was infiltration of eosinophils, lymphocytes and macrophages, although the degree and severity of inflammatory reaction varied case by case. Cerebral cortex also had the inflammatory exudate of lymphoid cells in the vicinity of the scolex. whereas perivascular lymphocytic cuffings were commonly seen around capsules. GFAP immunoreactive fibers formed a limiting membrane along the outer side of capsules. There was also proliferation of GFAP-positive astrocytes encirling infiltrating lymphocytes around vessels. In the central nervous system, astrocytes and lympoid cells play an important role in the demarcation of cysts and local immunity, respectively. In conclusion, host tissue reaction in porcine cysticercosis seemed to vary significantly according to the affected organs of pigs. It is assumed that capsules containing worms seemed to be formed at early stage of cysticercosis.