A multiscale approach for the reconstruction of the fiber architecture of the human brain based on 3D-PLI.
A multiscale approach for the reconstruction of the fiber architecture of the human brain based on 3D-PLI.
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DOI：
10.3389/fnana.2015.00118
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发表时间：
2015
影响因子：
2.9
通讯作者：
Axer M
中科院分区：
文献类型：
--
作者：
Reckfort J;Wiese H;Pietrzyk U;Zilles K;Amunts K;Axer M
大脑的结构性连接可以被概念化为一个多尺度的组织。本研究建立在3D偏振光成像(3D-PLI)的基础上，3D-PLI是一种神经成像技术，旨在重建神经纤维方向，因此有助于分析大脑连接。纤维的空间取向是由未染色的组织切片的双折射测量得出的，通过基于体素的分析来解释。这意味着为每个体素获得单个纤维取向向量，这反映了所有包含的纤维的净效果。我们使用了两种偏振测量装置，分别提供了1.3μm/px(显微装置)和μm/px(宏观装置)的物体空间分辨率，以执行3D-PLI并提取相同组织样本的纤维取向，但在互补的体素大小(即，尺度)下。本研究确定了在用两种偏振系统测量同一样品时，引起测量纤维取向不一致的主要来源。作为这样的来源，确定了所实施的波片的不同光学分辨率和发散延迟。实现了一种方法，能够对测量到的不同系统对同一双折射样品的响应进行补偿。这为利用3D-PLI在大脑中进行多尺度分析开辟了新的途径，并为不同尺度的神经纤维结构之间的转换提供了可靠的基础。
Structural connectivity of the brain can be conceptionalized as a multiscale organization. The present study is built on 3D-Polarized Light Imaging (3D-PLI), a neuroimaging technique targeting the reconstruction of nerve fiber orientations and therefore contributing to the analysis of brain connectivity. Spatial orientations of the fibers are derived from birefringence measurements of unstained histological sections that are interpreted by means of a voxel-based analysis. This implies that a single fiber orientation vector is obtained for each voxel, which reflects the net effect of all comprised fibers. We have utilized two polarimetric setups providing an object space resolution of 1.3 μm/px (microscopic setup) and 64 μm/px (macroscopic setup) to carry out 3D-PLI and retrieve fiber orientations of the same tissue samples, but at complementary voxel sizes (i.e., scales). The present study identifies the main sources which cause a discrepancy of the measured fiber orientations observed when measuring the same sample with the two polarimetric systems. As such sources the differing optical resolutions and diverging retardances of the implemented waveplates were identified. A methodology was implemented that enables the compensation of measured different systems' responses to the same birefringent sample. This opens up new ways to conduct multiscale analysis in brains by means of 3D-PLI and to provide a reliable basis for the transition between different scales of the nerve fiber architecture.