期刊
NEUROIMAGE
卷 244, 期 -, 页码 -出版社
ACADEMIC PRESS INC ELSEVIER SCIENCE
DOI: 10.1016/j.neuroimage.2021.118576
关键词
Connectome; Diffusion MRI; Tractography; Neural tracer; Graph theory; Geometric networks
资金
- National Institutes of Health (NIH) [F31NS113571, R01EB026300, U01MH109100, S10OD025081, S10RR021039, P30CA14599]
Diffusion MRI tractography is a noninvasive method for measuring the structural connectome in humans, but recent studies have shown limitations due to local uncertainties in fiber orientations. Geometry plays a larger role in determining the topology of graphs produced by tractography compared to neural tracers, underestimating weights at long distances and affecting the placement of network hubs. The role of spatial embedding in modular structure and network efficiency is explored in both modalities, with geometric biases inherent in tractography quantified for future validation efforts.
Diffusion MRI tractography is the only noninvasive method to measure the structural connectome in humans. However, recent validation studies have revealed limitations of modern tractography approaches, which lead to significant mistracking caused in part by local uncertainties in fiber orientations that accumulate to produce larger errors for longer streamlines. Characterizing the role of this length bias in tractography is complicated by the true underlying contribution of spatial embedding to brain topology. In this work, we compare graphs constructed with ex vivo tractography data in mice and neural tracer data from the Allen Mouse Brain Connectivity Atlas to random geometric surrogate graphs which preserve the low-order distance effects from each modality in order to quantify the role of geometry in various network properties. We find that geometry plays a substantially larger role in determining the topology of graphs produced by tractography than graphs produced by tracers. Tractography underestimates weights at long distances compared to neural tracers, which leads tractography to place network hubs close to the geometric center of the brain, as do corresponding tractography-derived random geometric surrogates, while tracer graphs place hubs further into peripheral areas of the cortex. We also explore the role of spatial embedding in modular structure, network efficiency and other topological measures in both modalities. Throughout, we compare the use of two different tractography streamline node assignment strategies and find that the overall differences between tractography approaches are small relative to the differences between tractography- and tracer-derived graphs. These analyses help quantify geometric biases inherent to tractography and promote the use of geometric benchmarking in future tractography validation efforts.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据