High-resolution imaging of distinct human corpus callosum microstructure and topography of structural connectivity to cortices at high field
High-resolution imaging of distinct human corpus callosum microstructure and topography of structural connectivity to cortices at high field
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DOI：
10.1007/s00429-018-1804-0
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发表时间：
2019-03-01
影响因子：
3.1
通讯作者：
Chen, Wei
中科院分区：
文献类型：
--
作者：
Lee, Byeong-Yeul;Zhu, Xiao-Hong;Chen, Wei
人类胼胝体 (CC) 的微观结构特性和地形特征是了解半球间神经通讯和大脑功能的关键。在这项工作中，我们测试了这样的假设：高场高分辨率 T-1 弛豫测量对于表征人类 CC 的微观结构特性具有足够的灵敏度和特异性，并阐明胼胝体纤维与起源皮质的结构连接性。从健康受试者 (N=16) 在 7T 获得的高分辨率参数化 T-1 图像清楚地显示了个体之间一致的 T-1 分布，沿人类 CC 轴存在显着差异，这与基于组织学研究的髓磷脂密度和有髓轴突大小的空间模式高度相似。与 CC 的前部相比，后中体和压部的 T-1 值显着更高。与基于 T-1 的分类方法相结合，与传统的划分方法相比，对压部 T-1 值的解码更加可靠，显示下压部的 T-1 值比中/上压部的 T-1 值高得多。此外，胼胝体细分的T-1轮廓代表了与投射皮质区域的纤维连接的拓扑结构：具有较高T-1（推断更大的轴突尺寸）的后中体和下压部的纤维主要分别连接到运动感觉和视觉皮质区域；相反，T-1 较低（推断轴突尺寸较小）的前/后 CC 中的纤维主要连接到额/顶颞区。这些发现表明，高分辨率 T-1 松弛测量成像可以提供一种补充且强大的神经成像工具，有助于探索人类胼胝体的复杂组织特性和地形组织。
Characterization of the microstructural properties and topography of the human corpus callosum (CC) is key to understanding interhemispheric neural communication and brain function. In this work, we tested the hypothesis that high-resolution T-1 relaxometry at high field has adequate sensitivity and specificity for characterizing microstructural properties of the human CC, and elucidating the structural connectivity of the callosal fibers to the cortices of origin. The high-resolution parametric T-1 images acquired from healthy subjects (N=16) at 7T clearly showed a consistent T-1 distribution among individuals with substantial variation along the human CC axis, which is highly similar to the spatial patterns of myelin density and myelinated axon size based on the histology study. Compared to the anterior part of the CC, the posterior midbody and splenium had significantly higher T-1 values. In conjunction with T-1-based classification method, the splenial T-1 values were decoded more reliably compared to a conventional partitioning method, showing a much higher T-1 value in the inferior splenium than in the middle/superior splenium. Moreover, the T-1 profile of the callosal subdivision represented the topology of the fiber connectivity to the projected cortical regions: the fibers in the posterior midbody and inferior splenium with a higher T-1 (inferring a larger axon size) were mainly connected to motor-sensory and visual cortical areas, respectively; in contrast, the fibers in the anterior/posterior CC with a lower T-1 (inferring a smaller axon size) were primarily connected to the frontal/parietal-temporal areas. These findings indicate that high-resolution T-1 relaxometry imaging could provide a complementary and robust neuroimaging tool, useful for exploring the complex tissue properties and topographic organization of the human corpus callosum.