Analysis of Multi-Voxel Patterns of Activity in fMRI data

描述(由申请人提供)：功能磁共振成像实验产生大量的、数字丰富但有噪声的数据集，这对提取信号方差和建立信号与认知变量之间的对应关系构成了挑战。传统的分析通过搜索对实验操作表现出相似反应的体素簇并对这些簇中的信号进行平均来降低fMRI数据的维度。我们引入了一种新的功能磁共振数据分析方法，“多体素模式分析”，它检查了更高的空间频率活动模式--一个区域内反应的体素变化--并表明这种方法极大地提高了功能磁共振成像的敏感性(Haxby等人。2001年；Hanson等人。2004年；OToole等人。2004年；Polyn等人。2004年)。在拟议的研究中，我们将针对功能磁共振数据分析中的两个具体问题，开发新的方法来分析神经活动的空间分布模式：1.解释功能神经解剖学中的个体间差异；2.空间分布的神经群体反应与认知表征之间的关系。这项工作将涉及一个由认知神经科学家、应用数学家和信号处理工程师组成的多学科团队的努力。我们建议开发分析方法，以基于由广泛的认知活动引发的神经活动模式来调整个体大脑的功能神经解剖学。我们预测，这些方法将提高fMRI数据的群体统计测试的敏感性，将允许调查较高空间频率的地形图的个体间一致性，并将提供关于功能图的位置、组织和空间范围的个体间差异的明确测量，具有潜在的临床条件研究应用。我们进一步建议开发检测和分析神经活动的分布模式的方法，这些方法利用与这些神经活动相关联的认知表征的结构的先验知识。我们预测，这些方法将提高多体素模式分析的灵敏度，并将允许研究认知信息如何在神经活动的拓扑组织和空间分布模式中表示。

DESCRIPTION (provided by applicant): fMRI experiments produce large, numerically rich, but noisy data sets that pose a challenge for extracting the signal variance and establishing the correspondence between that signal and cognitive variables. Conventional analysis has reduced the dimensionality of fMRI data by searching for clusters of voxels that show similar responses to experimental manipulations and averaging the signal within those clusters. We have introduced a new approach to fMRI data analysis, "multi-voxel pattern analysis", that examines higher spatial frequency patterns of activity - the voxel-by-voxel variation of response within a region - and have shown that this method greatly increases the sensitivity of fMRI (Haxby et al. 2001; Hanson et al. 2004; OToole et al. 2004; Polyn et al. 2004). In the proposed investigations, we will develop new methods for analysis of spatially-distributed patterns of neural activity in relation to two specific problems in fMRI data analysis: 1. accounting for inter-individual variation in functional neuroanatomy, and 2. the relation between spatially-distributed neural population responses and cognitive representations. This work will involve the efforts of a multidisciplinary team consisting of cognitive neuroscientists, applied mathematicians, and signal- processing engineers. We propose the development of analytic methods for aligning the functional neuroanatomy of individual brains based on the patterns of neural activity that are elicited by a broad spectrum of cognitive activities. We predict that these methods will enhance the sensitivity of group statistical tests of fMRI data, will allow the investigation of the inter-individual consistency of higher spatial frequency topographic representations, and will provide explicit measures of inter-individual variation in the location, organization, and spatial extent of functional maps, with potential applications for studies of clinical conditions. We propose, further, to develop methods for detecting and analyzing distributed patterns of neural activity that make use of prior knowledge about the structure of the cognitive representations that are associated with those neural activities. We predict that these methods will increase the sensitivity of multi-voxel pattern analysis and will allow the investigation of how cognitive information is represented in topographically-organized, spatially-distributed patterns of neural activity.