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1.
视觉研究对于揭示大脑的奥秘有着极其重要的意义.功能性磁共振成像(functional magnetic resonance imaging,fMRI)用于研究人脑的功能结构,主要是基于静脉毛细血管内血氧浓度的变化.fMRI可以无损伤地在几毫米级的空间分辨率和少于1 s的时间分辨率上观察清醒状态下人脑的活动,因此自90年代以来fMRI已经成为研究人脑的重要方法.fMRI在视觉研究中的应用已经使人们对视觉系统的功能性组织有了更好的理解,并取得了很多成果.今后的研究方向是进一步探讨人脑的意识、注意、记忆等高级功能的神经机制.  相似文献   

2.
RNA结构具有多样性,RNA功能依赖于RNA结构,RNA结构承载着重要的生物信息。在人脑中,RNA结构可能承载着记忆信息编码的重要功能。对RNA结构作为生物信息的载体和人脑中记忆信息的载体,特别是瞬时记忆信息编码的载体进行了探讨。该假说的提出对阐释记忆的分子机制具有重要意义。  相似文献   

3.
电脑自1946年诞生以来,仅短短的四十年,因其功能神奇,遂迅猛发展。近年来微电脑犹如一颗夺目的新星,于人类社会的各个角落闪光,以惊人的速度闯入家庭和个人生活,成为人们离不开的服务工具。电脑虽然结构复杂,制作精密,但正是由于此才使其具有神奇的功能,代替人脑工作,甚至在速度、精度上是人脑望尘莫及的。电脑是人脑劳动的产物,它必定受到人脑的控制。由于从事电脑软、硬件设计研究人员的大量劳动,才使电脑的功能日益增多,对广大使用者来说操作却越趋直观、简便。电脑在科研工作管理、科研数据资料处理、科学计算、统计分析等领域中大有用武之地。在以古生物研究为主的单位同样可以发挥其美妙的功能,成为研究人员的好助手。如人类学研究中,统计分析是必不可  相似文献   

4.
《遗传》2021,(5)
人脑是自然界生物体内结构和功能最复杂的器官。解析人类基因组如何编码人脑的结构与功能是极具挑战的科学与技术问题,也是从根本上认识脑的本质问题。本文对近年来脑的"断面"组学研究的相关进展进行归纳,提出解析基因组如何编码脑的挑战与展望。  相似文献   

5.
人脑是自然界中最复杂的系统之一,不同的功能区域相互作用、互相协调,共同构成一个网络来发挥其功能。人脑是一个复杂的网络,具有高效的“小世界”拓扑属性。本文从脑结构到脑功能方面介绍了从不同模态影像学数据构造脑网络的主要进展,并探讨不同的脑疾病患者脑网络拓扑结构是否发生了异常,以及这些异常特征能否用来进行疾病分类,最后对本领域未来的研究做了简单的展望。  相似文献   

6.
脑功能磁共振成像是近年来磁共振成像技术的一项新发展,为从单一形态学研究到形态与功能相结合的系统研究开辟了一条崭新的道路。本文主要介绍了人脑的功能活动磁共振成像的概念、原理、试验设计、临床的研究现状。  相似文献   

7.
功能磁共振成像(fMRI)和扩散张量成像(DTI)是近年来磁共振成像领域出现的两种新的成像技术,它们各具特色。功能磁共振成像能对人脑相关任务激活区进行准确的功能定位并提供相关皮层区域的磁共振信号改变特征信息,但时于脑白质相关改变则不能提供任何信息;扩散张量成像则是目前能够在体呈现人脑解剖连接的唯一手段,采用它能对人脑组织,包括灰质和白质的扩散特性进行定量研究,并且能够形象显示人脑生理或病理状态下的纤维束形态、走行等,但扩散张量成像不能提供皮层功能情况信息。功能磁共振成像和扩散张量成像技术具有很强的互补性,二者联合在神经科学研究中具有广阔的应用前景。目前也正成为神经科学研究领域的热点之一。本文从功能磁共振成像和扩散张量成像的原理、特点,二者结合应用的具体方法以及目前二者在神经科学各基础及临床学科结合应用的研究进展进行了综述。  相似文献   

8.
抽象概念是人类概念系统的重要组成部分。随着脑功能影像技术的推广和广泛应用,以具体的客体和动作概念为研究对象的概念神经基础研究取得了一系列重要进展,但人脑表征和加工抽象概念的机制一直是个未解之谜。本文综述了抽象概念的认知理论和脑功能影像研究进展,发现抽象概念可通过语言和潜在具身信息进行表征,抽象概念的脑区基础与此认知框架有一定对应。未来研究需澄清语言和具身认知在抽象概念表征和加工的参与机制及其脑基础,从而推动人脑概念系统和相关类脑研究的进展。  相似文献   

9.
基于fMRI的脑功能整合数据分析方法综述   总被引:1,自引:0,他引:1  
脑功能成像在人脑信息处理和认知活动的神经关联中发挥了不可轻视的作用.从大脑功能整合出发,可以将脑功能成像数据分析方法分为探测大脑功能整合的功能连接和有效连接两方面,功能连接探究空间远离的两个脑区之间的连接,有效连接研究一个脑区对另一个脑区作用的大小.根据这两个概念,相应地可以将功能磁共振数据分析方法分为两大类.本文着重...  相似文献   

10.
神经活动的细胞的分子基础杨雄里1神经生物学研究的科学意义及其在社会发目申的作用动物的神经系统,特别是人脑,是自然界最复杂的系统。揭示脑的奥秘是当代自然科学面临的最大挑战之一。脑的研究具有重大的科学和哲学意义。作为长期进化的产物,人脑的结构、功能以及人...  相似文献   

11.
An intracellular concentration of cAMP is a factor to define activity of cAMP-dependent protein kinases. Enzyme activity changes in cytosol and microsomal fractions from investigated brain's regions. Two-phase character of posttraumatic changes of A-kinases activity is shown. Linear dependence for microsomal fractions obtained from brain's hemispheres is observed between A-kinases activity and calculated equilibrium cAMP concentration in different time after experimental cranial trauma.  相似文献   

12.
It was determined that tumor necrosis factor (TNF) is capable of decreasing the local brain's blood flow on 45.6% (in the concentration of 6 micrograms/kg); to make a spasm of the pial arteries on 39.6%. In vitro experiments TNF increased the amplitude of the rhythmical and the tonic contractions of the brain's arteries smooth muscles (3.6 X 10(-8) M). The direct action of the TNF in the vascular wall is endothelium-dependent.  相似文献   

13.
Moore DR 《Current biology : CB》2000,10(10):R362-R364
Speech is thought to be perceived and processed in a unique way by the auditory system of the brain. A recent study has provided evidence that a part of the brain's temporal lobe is specifically responsive to speech and other vocal stimuli.  相似文献   

14.
A new psychophysical study has examined the free flow of perception as observers viewed stimuli with several possible visual interpretations. The results suggest that our subjective impression of such ambiguous patterns may be more closely linked to the brain's encoding of complex shape than previously appreciated.  相似文献   

15.
Rates of conversion of alpha-linolenic acid (alpha-LNA, 18:3n-3) to docosahexaenoic acid (DHA, 22:6n-3) by the mammalian brain and the brain's ability to upregulate these rates during dietary deprivation of n-3 polyunsaturated fatty acids (PUFAs) are unknown. To answer these questions, we measured conversion coefficients and rates in post-weaning rats fed an n-3 PUFA deficient (0.2% alpha-LNA of total fatty acids, no DHA) or adequate (4.6% alpha-LNA, no DHA) diet for 15 weeks. Unanesthetized rats in each group were infused intravenously with [1-(14)C]alpha-LNA, and their arterial plasma and microwaved brains collected at 5 minutes were analyzed. The deficient compared with adequate diet reduced brain DHA by 37% and increased brain arachidonic (20:4n-6) and docosapentaenoic (22:5n-6) acids. Only 1% of plasma [1-(14)C]alpha-LNA entering brain was converted to DHA with the adequate diet, and conversion coefficients of alpha-LNA to DHA were unchanged by the deficient diet. In summary, the brain's ability to synthesize DHA from alpha-LNA is very low and is not altered by n-3 PUFA deprivation. Because the liver's reported ability is much higher, and can be upregulated by the deficient diet, DHA converted by the liver from circulating alphaLNA is the source of the brain's DHA when DHA is not in the diet.  相似文献   

16.
Mehta MR 《Cell》2011,147(5):968-970
The brain's grid and place cells, which contribute to spatial representations of the external environment, are thought to be modulated by the hyperpolarization-activated cation current (I(h)). Giocomo et al. and Hussaini et al. now provide new insights into these cells' unique activity patterns by studying transgenic mice lacking I(h).  相似文献   

17.
Addictive drugs hijack the human brain's 'reward' systems. A zebrafish model of addiction has recently been used to query changes in gene expression during this process.  相似文献   

18.
Borst A 《Neuron》2007,54(1):6-8
Researchers who study the neuronal basis of cognition face a paradox. If they extract the brain, its cognitive functions cannot be assessed. On the other hand, the brain's microcircuits are difficult to study in the intact animal. In this issue of Neuron, Mitchell et al. make use of a promising approach based on waveform analysis to reveal new details about neuronal interactions during visual attention.  相似文献   

19.
The parietal cortex is a central part of the brain's system for representing numbers and magnitudes. Activity in the parietal cortex might reflect number representation or actions made in response to the numbers.  相似文献   

20.
1. Fenestrated vessels can be reversibly induced in brain by agents that stimulate urokinase production. This plasminogen activator, like vascular endothelial growth factor and metalloproteinases, is secreted by tumor cells and may account for induction of fenestrated vessels. Why only some of the brain's barrier vessels are converted to fenestrated vessels is unknown.2. The structures responsible for the filtering of solutes by fenestrated vessels may be the same as those of continuous, less permeable vessels: the glycocalyx on the surfaces of the endothelial cells and the subendothelial basal lamina.3. Solutes leaving the cerebral ventricles immediately enter the interstitial clefts between the cells lining the ventricles. A fraction of a variety of solutes, injected into CSF compartments, is retained by subendothelial basal lamina, from which the solutes may be released in a regulated way.4. The brain's CSF and interstitial clefts are the conduits for nonsynaptic volume transmission of diffusible signals, e.g., ions, neurotransmitters, and hormones. This type of transmission could be abetted by a parallel, cell-to-cell volume transmission mediated by gap junctions between astrocytes bordering CSF compartments and parenchymal astrocytes.5. The width and contents of the interstitial clefts in fetal brain permit cell migration and outgrowth of neurites. The contents of the narrower and different interstitial clefts of mature brain permit solute convection but must be enzymatically degraded in order for cells to migrate through it.  相似文献   

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