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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
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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
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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
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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
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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
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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
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S N Kucherenko L I Ostapenko A N Vasil'ev 《Biulleten' eksperimental'no? biologii i meditsiny》1989,107(4):433-435
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
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A L Azin N P Mitagvariia V G Medvedev I K Baratashvili A S Barybin 《Biulleten' eksperimental'no? biologii i meditsiny》1990,110(8):121-124
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
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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
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Leopold DA 《Current biology : CB》2003,13(1):R10-R12
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
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Igarashi M DeMar JC Ma K Chang L Bell JM Rapoport SI 《Journal of lipid research》2007,48(5):1150-1158
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
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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
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Jean Lud Cadet 《Genome biology》2009,10(7):231-4
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
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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
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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
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Huber R 《Current biology : CB》2007,17(10):R367-R368
Is a full night of sleep a waste of time? No, numerous studies show dramatic performance impairments after sleep restriction, and a new study now indicates that sleep deprivation diminishes the brain's ability to form new memories. 相似文献