scholarly journals Towards a comprehensive delineation of white matter tract-related deformation

2021 ◽  
Author(s):  
Zhou Zhou ◽  
Xiaogai Li ◽  
Yuzhe Liu ◽  
Madelen Fahlstedt ◽  
Marios Georgiadis ◽  
...  

AbstractFinite element (FE) models of the human head are valuable instruments to explore the mechanobiological pathway from external loading, localized brain response, and resultant injury risks. The injury predictability of these models depends on the use of effective criteria as injury predictors. The FE-derived normal deformation along white matter (WM) fiber tracts (i.e., tract-oriented strain) has recently been suggested as an appropriate predictor for axonal injury. However, the tract-oriented strain only represents a partial depiction of the WM fiber tract deformation. A comprehensive delineation of tract-related deformation may improve the injury predictability of the FE head model by delivering new tract-related criteria as injury predictors. Thus, the present study performed a theoretical strain analysis to comprehensively characterize the WM fiber tract deformation by relating the strain tensor of the WM element to its embedded fiber tracts. Three new tract-related strains were proposed, measuring the normal deformation vertical to the fiber tracts (i.e., tract-vertical strain), and shear deformation along and vertical to the fiber tracts (i.e., axial-shear strain and lateral-shear strain, respectively). The injury predictability of these three newly-proposed strain peaks along with the previously-used tract-oriented strain peak and maximum principal strain (MPS) were evaluated by simulating 151 impacts with known outcome (concussion or no-concussion). The results showed that four tract-related strain peaks exhibit superior performance compared to MPS in discriminating concussion and non-concussion cases. This study presents a comprehensive quantification of WM tract-related deformation and advocates the use of orientation-dependent strains as criteria for injury prediction, which may ultimately contribute to an advanced mechanobiological understanding and enhanced computational predictability of brain injury.HighlightDeformation of white matte fiber tracts is directly related to brain injury, but only partially analyzed thus far.A theoretical derivation that comprehensively characterizes white matter tract-related deformation is conducted.Analytical formulas of three novel tract-related strains are presented.Tract-related strain peaks are better predictors for concussion than the maximum principal strain.

2017 ◽  
Vol 34 (2) ◽  
pp. 291-299 ◽  
Author(s):  
Juan J. Herrera ◽  
Kurt Bockhorst ◽  
Shakuntala Kondraganti ◽  
Laura Stertz ◽  
João Quevedo ◽  
...  

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Tatsuya Jitsuishi ◽  
Atsushi Yamaguchi

Abstract The intraparietal sulcus (IPS) in the posterior parietal cortex (PPC) is well-known as an interface for sensorimotor integration in visually guided actions. However, our understanding of the human neural network between the IPS and the cortical visual areas has been devoid of anatomical specificity. We here identified a distinctive association fiber tract “IPS-FG” to connect the IPS areas and the fusiform gyrus (FG), a high-level visual region, by white matter dissection and tractography. The major fiber bundles of this tract appeared to arise from the medial bank of IPS, in the superior parietal lobule (SPL), and project to the FG on the ventral temporal cortex (VTC) in post-mortem brains. This tract courses vertically at the temporo-parieto-occipital (TPO) junction where several fiber tracts intersect to connect the dorsal-to-ventral cortical regions, including the vertical occipital fasciculus (VOF). We then analyzed the structural connectivity of this tract with diffusion-MRI (magnetic resonance imaging) tractography. The quantitative tractography analysis revealed the major streamlines of IPS-FG interconnect the posterior IPS areas (e.g., IP1, IPS1) with FG (e.g., TF, FFC, VVC, PHA2, PIT) on the Human Connectome Project multimodal parcellation atlas (HCP MMP 1.0). Since the fronto-parietal network, including the posterior IPS areas, is recruited by multiple cognitive demands, the IPS-FG could play a role in the visuomotor integration as well as the top-down modulation of various cognitive functions reciprocally.


2017 ◽  
Vol 38 (4) ◽  
pp. 814-819 ◽  
Author(s):  
M. Ishaque ◽  
J.H. Manning ◽  
M.D. Woolsey ◽  
C.G. Franklin ◽  
F.S. Salinas ◽  
...  

2018 ◽  
Vol 14 ◽  
pp. 174480691881029 ◽  
Author(s):  
Albert Leung ◽  
Eric Yang ◽  
Michael Lim ◽  
Valerie Metzger-Smith ◽  
Rebecca Theilmann ◽  
...  

Author(s):  
Natalia Zakharova ◽  
Valery Kornienko ◽  
Alexander Potapov ◽  
Igor Pronin

2011 ◽  
Vol 17 (6) ◽  
pp. 633-644 ◽  
Author(s):  
Andreas Kleinschmidt ◽  
Elena Rusconi

That disconnection causes clinical symptoms is a very influential concept in behavioral neurology. Criteria for subcortical disconnection usually are symptoms that are distinct from those following cortical lesions and damage to a single, long-range fiber tract. Yet, a recent study combining functional magnetic resonance imaging and fiber tracking concluded that a focal lesion in left parietal white matter provides the only tenable explanation for pure Gerstmann’s syndrome, an enigmatic tetrad of acalculia, agraphia, finger agnosia, and left-right disorientation. Such a lesion would affect not only a single fiber tract but crossing or “kissing” of different fiber tracts and hence disconnect separate cortical networks. As fiber crossing is prominent in the cerebral white matter, the authors propose an extension to the subcortical disconnection framework that opens the door to ascribing a more diversified clinical phenomenology to white matter damage and ensuing disconnection than has been the case so far.


2018 ◽  
Vol 35 (8) ◽  
pp. 1015-1020 ◽  
Author(s):  
Sohae Chung ◽  
Els Fieremans ◽  
Xiuyuan Wang ◽  
Nuri E. Kucukboyaci ◽  
Charles J. Morton ◽  
...  

2021 ◽  
Author(s):  
Zhou Zhou ◽  
Teng Wang ◽  
Xiaogai Li

Incorporating neuroimaging-revealed structural details into finite element (FE) head models opens vast opportunities to understand brain injury mechanisms. Recently, growing efforts have been made to integrate the fiber orientation from diffusion tensor imaging into the FE models to compute white matter (WM) tract-related deformation. Commonly used approaches often downsample the spatially enriched fiber orientation to match the resolution of FE meshes, resulting in an element-wise orientation implementation. However, the validity of downsampling and the consequences on the computed tract-related strains remain elusive. To address this problem, the current study proposed a new voxel-wise approach to integrate fiber orientation into FE models without downsampling. By setting the voxel-wise orientation responses as the reference, we then evaluated the reliability of two existing downsampling approaches on tract-related strains using two FE models with varying element sizes. The results showed that, for a model with a large mesh-image resolution dismatch, the downsampling orientation exhibited an absolute difference over 30 degree across the WM/gray matter interface and pons regions and further negatively affects the computation of tract-related strains with the normalized root-mean-square error up to 20% and peaking tract-related strains underestimated by 5%. This downsampling-induced effect was lower in FE models with finer meshes. Thus, this study yields insights on integrating neuroimaging-revealed fiber orientation into FE models and may better inform the computation of WM tract-related deformation, which are crucial for advancing the etiological understanding and computational predictability of brain injury.


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