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静息及视觉任务状态下面孔认知脑区的fMRI功能网络研究
Alternative TitleStudies of Functional Network for Face Perception During Visual Task and Resting states
张慧
Subtype工学博士
Thesis Advisor田捷
2009-05-29
Degree Grantor中国科学院研究生院
Place of Conferral中国科学院自动化研究所
Degree Discipline计算机应用技术
Keyword功能磁共振成像 面孔认知 静息态 功能连接度 脑网络 Bold-fmri Face Perception Resting States Functional Connectivity Brain Network
Abstract面孔的感知和识别在人类的社会交往中扮演着及其重要的角色,人在感知面孔的时候,从中获取了大量重要的信息,这些信息提供给我们个体的身份特征和精神状态,从而确定彼此之间的相互关系和交流方式。那么大脑如何对看到的面孔进行识别和加工?通过早期对脑损伤病人以及与人类相似种群短尾猴的研究人们逐渐发现,人的大脑中可能存在着专门用来负责进行面孔加工的脑区,但是由于早期成像技术无法对健康人进行非侵入式的高空间分辨率脑图像获取,我们始终不能给这一问题一个合理的答复。随着以BOLD-fMRI为代表的功能磁共振成像技术的出现和不断完善,人类对面孔认知和加工机制的研究进入了一个全新的发展阶段。 长期以来学术界一直存在着这样一个争论: 在多大程度上某一特殊的高层次认知功能由不同的脑区完成?现在普遍的观点认为:大脑中单一的脑区很可能参与了多个功能任务的完成.对于面孔加工这样一个特殊的高层次视觉任务,大量证据支持这样一个假设:面孔感知,不但有特殊的功能脑区负责加工,而且由一个特殊的皮层网络来参与完成。本文采用BOLD-fMRI技术来研究大脑在面孔加工方面的神经机制,从两个角度:面孔加工的功能特异性和功能整合性来探讨大脑中对面孔加工具有特殊反应的脑区和以及这些脑区的分布和组织构成。 很久以来人们一直认为,人在不执行任务或感受外界刺激时,大脑活动是相对平稳的而且无规律可寻的。而近来的研究却发现,在无外界刺激闭眼休息的静息状态下,某些功能脑区之间存在着同步的低频涨落,暗示了这些脑区之间仍存在着功能上的连接。这一现象已经在双侧的听觉、视觉区以及静息状态下的缺省网络中得到了证实。那么在静息状态下,与面孔加工相关的脑区之间是否存在着连接关系?视觉任务状态下的面孔加工脑网络是临时自组织起来的还是大脑中固有的?或者说大脑中是否存在着一个不依赖于外界视觉刺激的、固有的面孔加工脑网络?本文通过静息状态下面孔加工脑区的连接关系及脑网络组织结构的研究来为这些问题的解答提供依据。 随着MRI 技术的进步,原始扫描得到的fMRI 图像空间分辨率不断提高,这为我们在更精细的空间尺度上研究人脑功能提供了可能。然而当前的fMRI 数据分析方法大都是基于一元的(基于种子区域的功能连接度分析方法),没有充分利用数据中包含的局部空间结构信息;同时为提高信噪比采用的高斯平滑在滤除噪声的同时也会不加分辨的将空间精细结构信息滤掉。这些处理方式造成了后续计算的连接度图谱的模糊和连接关系统计的不精确。这一问题在分析面孔认知的脑功能连接问题时同样存在。那么如何有效的提取具有空间精细结构信息的脑区之间的连接?这也是本文即将探讨的一个重要问题。 本文以fMRI技术为研究手段,从功能特异和功能整合两个分析角度入手,探讨了静息和被动视觉任务状态下的面孔加工神经机制问题。同时针对传统的一元连接度分析方法存在的问题,详细介绍了一种能有效提取空间精细结构信息的脑功能连接度提取方法,并应用于面孔加工脑区功能连接度的计算中。本文主要研究内容包括以下这几个方面: (1) 从功能特异性和功能整合性分析面孔加工...
Other AbstractFaces are the most important visual stimuli we perceive. They play a paramount role in our everyday social interactions with others. We obtain large amout of information when perceiving faces. Faces inform us not only about a person’s identity, but also about their mood, sex, age and direction of gaze. How brain perceives and processes the face stimuli? One of the evidence came from the syndrome of acquired prosopagnosia, in which neurological patients lose ability to recognize faces after brain damage. Studies from monkeys also show stunning face specificity at both the single-cell level and the level of cortical regions. These evidences suggest there exist a cortical region specialized for the perception of faces. However, due to that the early imaging technology can not provide non-invasive and high temporal-spatial resolution imaging for healthy with large area of cortex, we can not give this issue an explicit answer. Along with the advent and rapid development of the BOLD-fMRI technology, the issues of face perception and recognition have come to a new stage. One of the longest running debates in the history of neuroscience concerns the degree to which specific high-level cognitive functions are implemented in discrete regions of the brain specialized for just that function. The currently popular view think that complex congntive functions are conducted in distributed and overlapping neural networks.For the perception of faces, large amout of evidence supports the hypothesis that face perception is implemented not only in specialized functional regions, but also a distributed cortical network. In this dissertation, the neural mechanism of face perception is investigated by using Blood-oxygen-level dependent functional magnetic resonance imaging technique (BOLD-fMRI). Under two important contents: the functional specification and the functional integration, the dissertation will focused on the studies of the face specialized brain regions and the connections and interactions of these regions in different states for discussion. For a long time people have always deemed that without the external stimuli, the activities in the brain are steady and irregular. The recent studies, however, find that some spatially discrete regions show synchronous low frequency-fluctuations. By using spontaneous low-frequency fluctuations in BOLD-fMRI, a set of widely distributed resting-state networks have been identified, with its frequency limited between 0.0...
shelfnumXWLW1381
Other Identifier200618014629082
Language中文
Document Type学位论文
Identifierhttp://ir.ia.ac.cn/handle/173211/6187
Collection毕业生_博士学位论文
Recommended Citation
GB/T 7714
张慧. 静息及视觉任务状态下面孔认知脑区的fMRI功能网络研究[D]. 中国科学院自动化研究所. 中国科学院研究生院,2009.
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