• Applied Microscopy
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• v.42 no.2
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• pp.77-86
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• 2012

The morphological and histologic differentiation of the central nervous system (CNS) in the wolf spider Arctosa kwangreungensis with respect to postembryonic development are studied using light and scanning electron microscopes. The organization of CNS which consisted of supraesophageal ganglion (SpG) and subesophageal ganglion (SbG) are established prior to the postembryo stage. The brain of first instar spiderling after a molt of the postembryo is also made up of supraesophageal ganglion and subesophageal ganglion. Although development of the optic nerve and optic lobe in SpG are not completed during the postembryoic stage, completion of whole neural system resemble to that of adult are established during the second instar stage. In particular, optic gangalion is developed from the undifferentiated cell clusters of the SpG, moreover four pairs of appendage ganglia and another pairs of abdominal ganglia are produced from the SbG. Nerve cells of the most developing stages are composed of typical monopolar neur1ons, and total three types of neurons can be identified through the histological and morphological basis of present study. These cell clusters are differentiated into neurons and grow dendritic fibers according to further development of the CNS.

• The Korean Journal of Zoology
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• v.38 no.4
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• pp.542-549
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• 1995

The effect of extraceflular matrix (ECM) protein on the neuronai differentiation of SI(-N-SH and IMR-32 human neuroblastoma cell lines was examined. When ceils were cultured on the laminin/collagen coated plate for 7 days, the extensive neurite outgrowth was observed In IMR-32. To address the reason why IMR-32 cell llne did not respond to ECM proteins, the ECM mediated early signalling mechanisms were analysed in both SK-N-SH and IMR-32. When cells were plated on the laminin/collagen coated plates, tyrosine phosphorylated proteins were Increased within an hour In both of these cells. Moreover, the foaal adhesion IlInase (FAK) was tyrosine phosphorylated in both of these two cell lines. These results suggest that the ECM mediated early signalling mechanism was normal in IMR-32 cell line. The expression of both NSE and Bcl-2 was increased by ECM treatment in SK-N-SH. However, these components were not changed by ECM In IMR 32 cells to ECM component Is likely due to the abnomality of the transcriptional regulation mechanism which Is responsible for the neuronal differentiation.

• Applied Microscopy
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• v.32 no.1
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• pp.67-80
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• 2002

This study was carried out to investigate the effects of deer antler extract on the regeneration of peripheral nerves. Sprague-Dawley male rats weighing about 300 gm were fed deer antler extract for 1, 2, and 3 weeks per oral (1.5 ml/100 gm B.W.), respectively, once a day and transected both sides of sciatic nerve of each leg. After keeping for 6 hours, sciatic nerves taken from proximal part of transected region were treated with conventional transmission electron microscopical method and then observed with electron microscope. The results obtained were summarized as follows; 1. Sciatic nerves of normal control group were not showing any sprouts and electron dense axolemmal projections were frequently observed. 2. Sciatic nerves of saline treated groups were showing axonal sprouts at the nodes of Ranvier. The length of them was usually short, and numerous vesicles, vacuoles and organelles including neurofilament were contained. The number of nodes of Ranvier containing sprouts from 100 longitudinal sectioned nerve fibers was 29 (29%) in 1 week treated group, 32 (32%) in 2 weeks treated group, and 30 (30%) in 3 weeks treated group, respectively. 3. Sciatic nerves of deer antler treated groups were showing axonal sprouts at the node of Ranvier as well. Although most of the sprouts were short, some sprouts of 2 weeks and 3 weeks treated groups were quite long. Sprouts usually contained numerous vesicles, vacuoles and cell organelles such as neurofilaments and mitochondria. The number of nodes of Ranvier containing sprouts from 100 longitudinal sectioned nerve fibers was 38 (38%) in 1 week treated group, 46 (46%) in 2 weeks treated group, and 48 (48%) in 3 weeks treated group respectively. The results described above explain pretreatment of deer antler extract improves the sprout formation of transected sciatic nerves, and then it suggests deer antler may be effective for the regeneration of peripheral nerves.

• Korean Journal of Cognitive Science
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• v.8 no.4
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• pp.11-18
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• 1997

야간 시각은 민감도를 극대화하고 주간 시각은 세감도를 극대화한다. 민감도와 세감도는 시각 기능의 두 목표이지만 상쇄적인 작용때문에 균형적인 선택이 요구된다. 민감도와 세감도를 결정하는 중요한 요인으로는 광학적인 요인과 신경학적인 요인이 있다. 망막의 지역적 분화는 바로 이러한 민감도-세감도 문제에서 기인하는데 망막의 2차원적인 제약이 시각신경계의 병행적인 경로와 이에 기초한 적응적 진화를 통해서 어느 정도 해소되는 듯이 보인다. 이 글은 야행-주행 습성을 동시에 갖추어 민감도와 세감도의 균형 문제가 각별히 부각되는 고양이의 초기 시각신경계에서 민감도와 세감도의 균형을 최적화하는 신경 기전을 소개한 것이다.

• The Science & Technology
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• v.33 no.10 s.377
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• pp.86-87
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• 2000

21세기를 주도하는 과학은 생물학으로 생명의 기원을 실험실에서 재생할 것이며 또 금속과 실리콘 신경과 근육이 함께 어우러져 일어나는 산업혁명이 시작될 것이다. 우리는 1백년 안에 소행성에 식민지를 건설하고 천년 후엔 인류도 다양하게 분화되며 1만년 단위로 보면 인간진화의 싸움터는 생물학에서 철학으로 옮겨갈 것이다.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.51 no.4
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• pp.152-159
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• 2002

Fitness sharing that shares fitness if calculated distance between individuals is smaller than sharing radius is one of the representative speciation methods and can complement evolutionary algorithm which converges one solution. Recently, there are many researches on designing neural network architecture using evolutionary algorithm but most of them use only the fittest solution in the last generation. In this paper, we elaborate generating diverse neural networks using fitness sharing and combing them to compute outputs then, propose calculating distance between individuals using modified Kullback-Leibler entropy for improvement of fitness sharing performance. In the experiment of Australian credit card assessment, breast cancer, and diabetes in UCI database, proposed method performs better than not only simple average output or Pearson Correlation but also previous published methods.

• The Zoological Society Korea : Newsletter
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• v.18 no.2
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• pp.26-32
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• 2001

동물에서 맛을 느끼는 것과 의사소통이 라는 행위는 생명을 유지하는데 있어 매우 중요한 수단이다. 섭취 할 수 있는 것과 먹어서는 안 되는 물질을 가려내고, 위험으로부터 벗어 날 수 있는 정보를 가장 빠르게 전달 할 수 있는 수단이다. 이러한 기능을 가지고 있는 몸 안의 기관으로는 혀가 있는데, 다양한 근육과 신경의 분포를 이용해서 위에서 언급한 기능을 수행하게 된다. 혀의 다양한 기능과 특징적인 구조에도 불구하고 현재까지는 혀의 감각기관으로써의 기능과 구조에 대한 연구가 대부분인 실정이다. 물론 발생학적 측면에서 다양한 접근이 이루어지고 있으나, 이 또한 신경의 분화와 유도에 대해서 초점을 맞추고 있는 것 이 사실이다. 생물학에 있어서 가장 중요한 초점은 항상 그 구조와 기능이지만 이러한 구조와 기능을 보다 정확하게 이해하기 위해서는 발생학적인 측면에서의 접근이 반드시 필요하고, 특히 Epithelium과 Mesenchyme의 interaction으로 생기는 외배엽성 기원 기관의 하나로써 혀의 papillae에 대한 고찰을 하고자 한다 (Jung et al 1998). 또한 현재까지 진행되어진 신경분포와 감각기관으로의 혀의 역할과 발생 과정에 대해서도 알아보고 이러한 현시점의 발생학과 형태학을 이해하는데 필요한 하나의 Model system으로써의 혀에 대해 이야기하고자 한다.

• KSBB Journal
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• v.18 no.3
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• pp.207-210
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• 2003

The locus coeruleus (LC) contains about half of the total number of noradrenergic neurons in the brain and those noradrenergic neurons from the LC innervate entire brain regions. The LC is a major common target region in several neurodegenerative disorders such as Alzheimer's, Pakinson's and Huntington's diseases. The brain-derived neurotrophic factor (BDNF) regulate neuronal cell survival and differentiation of central nervous system neurons, including LC noradrenergic neurons. In this study, various small molecules and growth factors were tested as candidates to promote the production of BDNF in LC noradrenergic neuronal cells. The molecules tested include neuropeptides, cytokines, growth factors, neurotransmitters, and intracellular signaling agents. Four small molecules or growth factors, FGF8b, BMP-4, forskolin, and dibutyryl cGMP, were found to increase the release of BDNF in LC noradrenergic neurons. Especially, BMP-4 significantly enhanced BDNF production over 2.5-fold in LC noradrenergic neurons.

• Annals of Clinical Neurophysiology
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• v.1 no.1
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• pp.10-18
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• 1999

연구배경 및 목적 : 시각 인지 과정은 영장류 실험을 통하여 다소 정보를 얻을 수 있었으나 인간에서는 아직 완전하게 이해되지 않고 있다. 이 연구의 목적은 뇌자극과 시가유발전위 검사를 토대로 인간의 시각피질의 기능적 분화와 시간 순으로 활성화되는 양상을 보고자 한 것이다. 연구방법 : 간질 수술을 위하여 후두엽과 인접 부위에 광범위하게 피질하전극을 넣은 22명의 환자를 대상으로 전기적 뇌자극과 시각유발전위 검사를 시행하였다. 뇌자극시 나타나는 반응은 형태, 색, 및 움직임의 세 가지로 크게 나누고 형태는 다시 단순, 중간 및 복잡한 형태로 세분하였다. 시각유발전위는 P1 혹은 IV파의 latency를 측정하였다. 결과 : 단순 혹은 중간 형태는 흔히 occipital pole과 striate cortex에서 발생하였다. 색반응은 후두엽의 기저부 즉, fusiform, lingual, inferior occipital gyri를 자극할 때 관찰되었다. 움직임 반응은 내측기저부 및 외측의 측후두엽 혹은 측두정후두부의 경계부에서 주로 나타났다. 결론 : 이러한 결과는 인간의 시각피질이 시각의 여러 가지 구성성분 즉, 형태, 색, 및 움직임에 대해서 각각 별도로 분화되어 있다는 것을 보여준다. 도한 시각자극이 전해지면 striate cortex와 occipital pole이 가장 먼저 활성화되고 이어서 내측 및 외측 후두엽 부위가 활성화된다는 것을 알 수 있다. 이러한 사실을 종합하여 보면 인간의 시각피질은 시각의 여러 구성성분별로 별도로 발달된 해부학적 경로를 통하여 각각의 기능에 대하여 특수하게 분화된 뇌세포에서 시각정보를 각각 분석하되 일정한 시간순서에 의한다는 것을 시사하는 것이다.

• Clinical and Experimental Pediatrics
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• v.49 no.10
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• pp.1100-1105
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• 2006

Purpose : Because NELL2 expression is strictly restricted only in neurons in developing and post-differentiated neural tissues, it is thought to be involved in the neuronal differentiation during development and in the maintenance of neuronal physiology in the post-differentiated neurons. In this study, we examined whether NELL2 is involved in the regulation of cell cycle and apoptosis in the hippocampal neuroprogenitor HiB5 cells. Methods : Effects of NELL2 on the cultured HiB5 cell numbers, DNA fragmentation, and proteins involved in the regulation of the cell cycle were measured. Results : NELL2 induced a decrease in cell numbers and an increase in G1 phase arrest. Moreover, transfection of NELL2 resulted in an increase of DNA fragmentation that shows an evidence of apoptosis. Contents of proteins involved in the regulation of cell cycle were also changed by transfection of NELL2 expression vectors. Conclusion : This study suggests that NELL2 plays an important role in the regulation of cell cycle and apoptosis of neurons.