The analysis of connectivity between parcellated regions of cortex provides insights into the functional architecture of the brain at a systems level. However, the derivation of functional structures from voxel-wise analyses at finer scales remains a challenge. We propose a novel method, called localized topo-connectivity mapping with singular-value-decomposition-informed filtering (or filtered LTM), to identify and characterize voxel-wise functional structures in the human brain from resting-state fMRI data. Here we describe its mathematical formulation and provide a proof-of-concept using simulated data that allow an intuitive interpretation of the results of filtered LTM. The algorithm has also been applied to 7T fMRI data acquired as part of the Human Connectome Project to generate group-average LTM images. Generally, most of the functional structures revealed by LTM images agree in the boundaries with anatomical structures identified by T1-weighted images and fractional anisotropy maps derived from diffusion MRI. In addition, the LTM images also reveal subtle functional variations that are not apparent in the anatomical structures. To assess the performance of LTM images, the subcortical region and occipital white matter were separately parcellated. Statistical tests were performed to demonstrate that the synchronies of fMRI signals in LTM-derived functional parcels are significantly larger than those with geometric perturbations. Overall, the filtered LTM approach can serve as a tool to investigate the functional organization of the brain at the scale of individual voxels as measured in fMRI.

中文翻译：

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使用局部拓扑连接映射的人脑功能分区


对皮质分区区域之间连接性的分析可以在系统层面上深入了解大脑的功能架构。然而，从更精细尺度的体素分析中推导功能结构仍然是一个挑战。我们提出了一种新方法，称为具有奇异值分解通知过滤（或过滤 LTM）的局部拓扑连接映射，用于从静息态 fMRI 数据中识别和表征人脑中的体素功能结构。在这里，我们描述了它的数学公式，并使用模拟数据提供了概念验证，从而可以直观地解释过滤后的 LTM 结果。该算法还应用于作为人类连接组项目一部分获取的 7T fMRI 数据，以生成组平均 LTM 图像。一般来说，LTM 图像揭示的大多数功能结构与 T1 加权图像和源自扩散 MRI 的分数各向异性图识别的解剖结构的边界一致。此外，LTM 图像还揭示了解剖结构中不明显的细微功能变化。为了评估 LTM 图像的性能，皮层下区域和枕叶白质被分别分割。统计测试表明，LTM 衍生的功能块中 fMRI 信号的同步性明显大于具有几何扰动的功能块。总体而言，过滤 LTM 方法可以作为一种工具，以功能磁共振成像 (fMRI) 测量的单个体素的规模来研究大脑的功能组织。