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1.
In 1846 Rudolf Virchow recognized for the first time that the vertebrate brain had a large population of cells other than the neurons, collectively called the neuroglia. Much later, various types of glial cells were identified and described (see Part 1) While pathologists studied glia extensively in normal and injured or diseased brains, most textbooks mentioned glia only cursorily. In the last decade, however, new techniques of identification of specific glial cells have given an impetus to the study of their role in the central nervous system (CNS). In this series, we aim to update students about these important other cells of the nervous system. The present article highlights some aspects of the structure and function of astrocytes, the major macroglia in the CNS. Other glial cell types will be discussed in subsequent articles. 相似文献
2.
Carl Ludwig Schleich (1859–1922) was an anaesthetist and a surgeon who for the first time emphasized the role of neuroglia
in brain function. In an era that was dominated by the idea that neurons alone were functional units of the nervous system
and that glial cells were a mere glue holding neurons in place, Schleich insisted that glia had a prominent functional role
to play. He suggested that interactions between neurons and glia were so strong that it is necessary to consider brain as
a neuron-glia system whose performance is dependent on both the cell types. Today Carl Ludwig Schleich is considered the forgotten
ancestor to a new breed of neurobiologists, the gliologists, who specialize in working on these neglected cells of the nervous
system. Though outnumbering the neurons and occupying almost half the volume of the brain, glial cells have been given little
importance in textbooks of neurobiology and are very often cursorily mentioned in discussions related to brain function. Glial
cells deserve a better deal, for over the years a lot of evidence has accumulated to prove that they perform a wide spectrum
of functions. This is the first of a series of articles that aims to update students on what is known about glia today. It
provides an overview of the various types of glia and their origins. The following articles will deal with each of the glial
sub-types and their functions. 相似文献
3.
氧化应激的产生与胞浆内活性氧簇的升高密切相关,过多生成的活性氧簇能够造成脂质过氧化,损伤蛋白质甚至DNA,而这些物质的受损与疾病发生相关,尤其是神经退行性疾病.神经退行性疾病经常被描述为进行性的神经元丢失,伴随神经元或者胶质细胞中出现标志性寡聚体.在神经退行性疾病中,胶质细胞可能以一种抗氧化应激的方式在神经元功能维持以及生存上发挥重要作用.反之,神经元也能够通过不同途径反馈调节胶质细胞.该文主要探讨在亨廷顿舞蹈症中胶质细胞的特点和功能,阐明氧化应激与亨廷顿舞蹈症的关系,概括这三者之间的关系进而论证胶质细胞在亨廷顿舞蹈症中的抗氧化应激保护作用. 相似文献
4.
绞股蓝皂甙和大豆皂甙对神经干细胞分化的影响 总被引：1，自引：0，他引：1
Neural stem cell has a potential to differentiate into neurons, astrocytes and oligodendrocytes. It provides an in vitro model to screen herbal medicines on the cellular differentiation and development level. In this work, active component from gypenosides and soyasaponins was prepared to investigate their effects on the differentiation of neural stem cells.. Both gypenosides and soyasaponins promote the differentiation of neural stem cells. This method provides speed and practicality for screening effective herbal medicine. It is well suited for studying the mechanism of cell differentiation and development. 相似文献
5.
体视学的基础是将复杂的几何学原理与统计学理论相结合。＂基于设计的体视学＂在神经科学实验研究中的应用,弥补了传统病理学在定量方面的不足,而成为该领域里的热点研究方法。如何实现研究目的区的体积测量、细胞（神经元、胶质细胞等）的计数、上述细胞或其内的亚细胞结构（胞核、线粒体等）的平均体积的估测、线性结构（神经纤维、血管等）长度的测量、阳性细胞的空间分布情况等逐渐成为研究焦点。该文综述了基于设计的体视学在神经科学研究中的应用,体视学对配套实验设备的要求,符合体视学要求的取样方法,对切片方向的要求及常用体视学参数。 相似文献
6.
Theodor Schwann, the German physiologist who first propounded the cell theory with M Schieiden, had diverse interests. He
was not only the first to isolate the enzyme pepsin, but also investigated muscle contraction and nerve structure. In the
mid nineteenth century Schwann discovered that a sheath made up of myelin covered the axons of neurons in the peripheral nervous
system (PNS). The cells that form the myelin are today called Schwann cells after him. Today, we know that the Schwann cells
not only form the myelin sheath around neurons, but also regulate several neuronal functions and are an indispensable part
of the PNS. 相似文献
7.
何茹 《思茅师范高等专科学校学报》2009,25(3):4-6
溶酶体是动物细胞中的细胞器,内含多种高浓度的酸性水解酶,目前已证实所含水解酶多达60多种,其主要功能是在细胞内起消化作用,对机体也有防御功能,并能清除衰老细胞和多余的细胞器。溶酶体酶出现异常而造成的疾病目前已发现多种,由于溶酶体对机体代谢有重要意义,因此对其的研究日益受到重视。 相似文献
8.
李蓉 《华中师范大学学报(人文社会科学版)》2005,44(2):103-109
沈从文文学观念中的善与美是一体的,对以生命为本的超越性的善的追求,使得沈从文文学观念中的善有一种终极性的价值指向,而这种善又是和美的形式合一的,体现为一种抽象之美。沈从文一方面非常重视文学对改造国民性的作用,另一方面他又认为这种功能的实现必须以审美的方式达成。这使他的文学观念既不同于启蒙作家,又不同于唯美派或纯文学作家。对于沈从文来说,他的试图融合多种对立因素的努力,在现实的层面上预示着一种悲剧的命运。 相似文献
9.
Cable方程是模拟神经元动力学最重要的方程之一,有关该方程的研究得到了越来越多的关注.最近的研究发现,用带有分数阶导数的Cable方程来模拟神经元的动力学行为效果更好.本文旨在考察时间分数阶Cable方程的初边值问题,构造了时间分数阶Cable方程的有限差分格式.对于时间半离散格式,我们证明了格式的稳定性,并给出了误差估计式. 相似文献
10.
刘建廷 《齐齐哈尔师范高等专科学校学报》2007,(1):75-78
社会转型时期，青海省的多元化利益群体日趋形成，青海省社会团体作为利益表达的主体，越来越独立于政府与市场，其作用日益受到全社会的重视。本文结合实际分析青海省社会团体在利益诉求机制上存在的问题，构建利益诉求的模型，并提出具体的对策，健全和完善利益诉求机制，形成社会成员维权活动的长效机制，增强社会聚合功效。 相似文献
11.
近年来，研究对婴儿的视觉注意进行了大量研究，得到很多有价值的发现。这些发现围绕婴儿注意功能的4个方面，即警觉、空间定向、对物体特征的注意和内源性注意，描述了婴儿视觉注意的发展过程．婴儿出生时，身上已分化出各种注意功能的初级形式，但是，每种注意功能都有不同的发展时期。主要表现在：从出生到2个月，婴儿的警觉状态发生并发展；从2或3个月6个月左右，婴儿的空间定向和物体注意功能有很大的变化；从5或6个月以后，婴儿的内源性注意功能变化明显。 相似文献
12.
对视神经神经纤维和胶质细胞的研究进展作了综述。主要包括视神经纤维的结构、数量、直径及其对兴奋的传导速度和视神经胶质细胞结构。 相似文献
13.
实验采用wistar大鼠18只,分为低磺组和正常组,于40日龄处死,取含弓状核的脑片,右侧做光镜观察,运用体视学原理,对弓状核神经元进行测量和计算。左侧做电镜观察。结果显示:低碘组弓状核神经元数密度增加,细胞体积减小,细胞核与细胞质平均体积减小。超微结构变化为:暗细胞增多,细胞内细胞器变性,次级溶酶体增多。在加碘组无上述变化,本结果提示了机体在低碘和甲状腺功能低下时,神经内分泌系统可能受到影响;其细胞的结构发生改变,必然影响细胞的功能。 相似文献
14.
Tomas Drunkenmölle 《Mind, Brain, and Education》2012,6(4):220-226
In current literature, metaphor is treated as either an instance of implicit comparison or as a nonliteral class‐inclusion statement. I will argue that, contrary to these positions, the notions of comparison and class‐inclusion are not mutually exclusive in character but rather complementary cognitive concepts which entail one another. While initially using the semantic distinction between literal and figurative language, I will argue in the course of this article that metaphor is a matter of extraordinary rather than ordinary language and that it reflects linguistic pragmatics rather than semantics. The most prominent reasons for resorting to the extraordinary use of language may be found in education, where metaphor serves a heuristic function in the interaction between teacher and student, and in scientific activities, when researchers have at their disposal only a restricted dictionary to describe new phenomena. Executive function, flashbulb memory, and the firing of neurons are examples from cognitive psychology and neuroscience that denominate phenomena that might otherwise not have been adequately expressed. I will conclude that metaphors are both comparisons as well as class‐inclusion statements and that these tropes fulfill not only a heuristic but also an epistemic function in as much as they render comprehensible the acquisition of radically new knowledge. 相似文献
15.
在四十多万字的文艺语体和科学语体语料的基础上,对排比辞格在两种语体中的结构形式和功能类型进行了考察．发现两种语体对排比辞格的结构形式和功能类型的吸收使用时是有差异的。 相似文献
16.
Studies investigating invariance have often been limited to measurement or prediction invariance. Selection invariance, wherein the use of test scores for classification results in equivalent classification accuracy between groups, has received comparatively little attention in the psychometric literature. Previous research suggests that some form of selection bias (lack of selection invariance) will exist in most testing contexts, where classification decisions are made, even when meeting the conditions of measurement invariance. We define this conflict between measurement and selection invariance as the invariance paradox. Previous research has found test reliability to be an important factor in minimizing selection bias. This study demonstrates that the location of maximum test information may be a more important factor than overall test reliability in minimizing decision errors between groups. 相似文献
17.
Much recent activity in the neurosciences relates to the search for the brain mechanisms underlying learning and memory. In recent years a brain circuit in cerebellum and brainstem has been discovered that is responsible for the learning of a simple motor response (nictitating membrane movement). This has provided a model for neuroscientists to use in understanding the brain circuits involved in this simple form of learning and, by extension, to more complex forms ultimately, and a means of exploring the changes in neural function underlying the learning. An enduring change in neural function is represented by long-term potentiation (LTP), an alteration in synaptic efficacy seen in hippocampus and other areas. LTP can be induced experimentally and occurs as a concomitant of learning. We review data suggesting that different brain circuits may underlie different forms of learning and memory. Several current theories of learning and memory with respect to hippocampal and other brain circuit involvement are considered. We conclude with the behavioral and physiological effects of exposure to teratogens or toxins and the CNS alterations associated with dementia. 相似文献
18.
黄冬珍 《徐州师范大学学报(哲学社会科学版)》2007,33(2):14-19
作为中国早期诗乐结合的乐歌,《风》诗在《诗经》中形式特征最为明显。虽然古人很早就注意到这个问题,可是受经学阐释的影响,这方面的研究并没有很好的展开。20世纪20-30年代从歌谣角度对《风》诗形式所进行的讨论,具有十分重要的意义。但是在后来相当长的时期里,学术研究更多关注《风》诗的思想内容,对艺术形式的研究重视不够。1980年代以后,不少论者从音乐角度与语言学角度研究《诗经》,取得了一些可资借鉴的成果。由于重视诗乐关系与文本分析,《风》诗的艺术形式研究在一些具体的方面有所深入。回顾古今学者的研究,我们发现,《风》诗艺术形式研究的状况,往往和那个时期人们对《风》诗性质及对诗乐关系的认识有密切关系。这说明,要推进和深化《风》诗艺术形式的研究,还需要对这些问题进行深入思考。 相似文献
19.
Addressing escape‐maintained behavior for students with developmental disabilities: A systematic review of school‐based interventions 
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下载免费PDF全文 Evan H. Dart Keith C. Radley Benjamin A. Mason Justin P. Allen 《Psychology in the schools》2018,55(3):295-304
Students with developmental disabilities have been found to exhibit higher rates of problem behavior in the classroom than their typically developing peers. Effectively addressing these students’ behavior concerns requires the identification of interventions that can be implemented in an educational setting. Furthermore, matching intervention strategies to the function of a student's problem behavior may increase its effectiveness. There are data to suggest that students with disabilities exhibit escape‐maintained problem behavior in the classroom twice as frequently as problem behavior maintained by other consequences such as attention or access to tangibles. Thus, the purpose of this systematic review was to identify school‐based intervention strategies that have been used to reduce the disruptive behavior of students with developmental disabilities. In total, 12 articles met search criteria, with escape extinction, curricular modification, and noncontingent escape serving as the most frequently employed intervention strategies. Limitations and future directions are discussed. 相似文献
20.
室内设计的任务，是为创造人们良好的工作学习、生活起居的环境，设计必须满足于使用功能和人类情感的要求。功能与形式存在着一种互补的关系，要重视对形式的处理，室内设计师的一项重要任务就是要创造美，创造美的环境。 相似文献