• Journal of Korean Neurosurgical Society
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• 제46권1호
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• pp.1-4
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• 2009

Objective: To report an unsuspected adaptive plasticity of single upper motor neurons and of primary motor cortex found after microsurgical connection of the spinal cord with peripheral nerve via grafts in paraplegics and focussed discussion of the reviewed literature. Methods: The research aimed at making paraplegics walk again, after 20 years of experimental surgery in animals. Amongst other things, animal experiments demonstrated the alteration of the motor endplates receptors from cholinergic to glutamatergic induced by connection with upper motor neurons. The same paradigm was successfully performed in paraplegic humans. The nerve grafts were put into the ventral-lateral spinal tract randomly, with out possibility of choosing the axons coming from different areas of the motor cortex. Results: The patient became able to selectively activate the re-innervated muscles she wanted without concurrent activities of other muscles connected with the same cortical areas. Conclusion: Authors believe that unlike in nerve or tendon transfers, where the whole cortical area corresponding to the transfer changes its function a phenomenon that we call "brain plasticity by areas". in our paradigm due to the direct connection of upper motor neurons with different peripheral nerves and muscles via nerve grafts motor learning occurs based on adaptive neuronal plasticity so that simultaneous contractions of other muscles are prevented. We propose to call it adaptive functional "plasticity by single neurons". We speculate that this phenomenon is due to the simultaneous activation of neurons spread in different cortical areas for a given specific movement, whilst the other neurons of the same areas connected with peripheral nerves of different muscles are not activated at the same time. Why different neurons of the same area fire at different times according to different voluntary demands remains to be discovered. We are committed to solve this enigma hereafter.

• BMB Reports
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• 제48권3호
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• pp.139-146
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• 2015

Adaptive brain function and synaptic plasticity rely on dynamic regulation of local proteome. One way for the neuron to introduce new proteins to the axon terminal is to transport those from the cell body, which had long been thought as the only source of axonal proteins. Another way, which is the topic of this review, is synthesizing proteins on site by local mRNA translation. Recent evidence indicates that the axon stores a reservoir of translationally silent mRNAs and regulates their expression solely by translational control. Different stimuli to axons, such as guidance cues, growth factors, and nerve injury, promote translation of selective mRNAs, a process required for the axon's ability to respond to these cues. One of the critical questions in the field of axonal protein synthesis is how mRNA-specific local translation is regulated by extracellular cues. Here, we review current experimental techniques that can be used to answer this question. Furthermore, we discuss how new technologies can help us understand what biological processes are regulated by axonal protein synthesis in vivo.

• Applied Microscopy
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• 제38권3호
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• pp.213-219
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• 2008

신경계통의 가소성은 신경세포의 변화에 의해 이루어질 뿐 아니라 신경아교세포의 변화에 의해서도 이루어진다. 신경아교세포 중 별아교세포는 신경세포의 기능을 조절하므로 정상적인 뇌의 기능을 유지하는데 매우 중요하다. 뇌에서 편도복합체는 위험 혹은 유해한 일련의 감각정보를 받아들이는 구역으로 받아들인 일련의 이와 같은 정보를 통합하고 변환시켜 공포라는 감정을 만들어낸다. 이런 과정은 편도복합체 신경세포에서 분비되는 신경전달물질의 균형변화에 의해 이루어지며, 신경전달물질의 조절에 별아교세포가 관여하므로 본 연구에서는 출생 전 스트레스와 성장 후에 받은 스트레스가 편도복합체 별아교세포의 세포체에 어떤 영향을 미치는지 조사하였다. 이를 위해 흰쥐를 스트레스를 받지 않은 대조군 (CON), 성장 후 스트레스를 받은 군 (CONR), 출생 전 스트레스를 받은 군 (PNS), 출생 전 스트레스와 성장 후 스트레스를 모두 받은 군 (PNSR)으로 구분하였다. 별아교세포는 GFAP 항체를 이용한 면역조직화학 염색을 시행하여 확인하였으며, methylene blue/azure II로 대조 염색하였다. Neurolucida 프로그램을 이용하여 계측한 별아교세포의 세포체는 일부 편도복합체 신경핵에서 출생 전 스트레스를 받은 PNS군이 대조군에 비하여 면적이 증가하였으며, 이런 경향은 출생 전 스트레스를 받고 다시 성장 후 스트레스를 받은 PNSR군에서 더욱 증가하였다. 따라서 흰쥐의 편도복합체에 분포하는 별아교세포는 스트레스에 영향을 받아 비대해지는 경향을 보인 것으로 나타났으며, 출생 전 스트레스가 성장 후에도 영향을 미치는 것으로 사료된다.