Exploratory Approach to fMRI Study with Fuzzy Clustering and General Linear Model
Exploratory Approach to fMRI Study with Fuzzy Clustering and General Linear Model
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DOI：
10.1109/fuzzy.2006.1681857
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发表时间：
2006-09
期刊：
影响因子：
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通讯作者：
H. Ichihashi;Katsuhiro Honda;A. Notsu;Takafumi Kurokawa
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文献类型：
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作者：
H. Ichihashi;Katsuhiro Honda;A. Notsu;Takafumi Kurokawa
功能性磁共振成像（fMRI）研究表明，不同的认知功能激活重叠的大脑区域，大脑的功能反应因区域而异。改进的模糊c均值（FCM）聚类用于fMRI信号的探索性分析，其中聚类中心代表了相对较宽脑区的典型血流动力学反应。本文展示了如何血氧水平依赖（BOLD）信号可以近似由少量的聚类质心，并提出了一个框架，允许FCM聚类技术与一般线性模型（GLM）结合实施。该方法说明了与回忆句子的fMRI实验。一个受试者使用记忆法巩固了英语句子的记忆，这种记忆法被称为轨迹法。在实验过程中，受试者通过回忆相关地点的图像来回忆句子。由于记忆法回忆是一项负荷很大的大脑活动，几乎是整个大脑同时激活。大脑激活广泛同步，观察到非常相似的激活模式。这使得很难区分大脑区域的作用。探索性方法阐明了不同大脑区域对回忆句子的繁重任务的轻微不同反应。
Functional magnetic resonance imaging (fMRI) studies have shown that different cognitive functions activate overlapping brain regions and the functional responses of the brain differ from region to region. The modified fuzzy c-means (FCM) clustering is used for exploratory analysis of fMRI signals in which the cluster centroids represent typical hemodynamics responses of relatively wide brain regions. This paper shows how blood oxygen level-dependent (BOLD) signals can be approximated by a small number of cluster centroids and presents a framework that allows FCM clustering technique to be implemented in conjunction with the general linear model (GLM). The approach is illustrated with an fMRI experiment of recalling sentences. A subject consolidated the memory of English sentences using mnemonics called the method of loci. During experimental session the subject recalled the sentences by recalling the images of their associated places. Because the recalling by way of mnemonics is a brain activity with heavy burden, almost the whole cerebrum activate simultaneously. The brain activations synchronized widely and quite similar activation patterns were observed. This makes it difficult to distinguish the roles of the brain regions. The exploratory approach clarifies the slightly different responses of different brain regions to the heavy tasks of recalling sentences.