Vertical Orbitofrontal Fascicles in the Brain: A Preliminary Confirmation via Diffusion Tractography
Poster No:
2189
Submission Type:
Abstract Submission
Authors:
Ye Wu1, Yifei He1, Tao Zhou1, Xiaoming Liu2
Institutions:
1School of Computer Science and Technology, Nanjing University of Science and Technology, Nanjing, China, 2Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and, Wuhan, China
First Author:
Ye Wu
School of Computer Science and Technology, Nanjing University of Science and Technology
Nanjing, China
School of Computer Science and Technology, Nanjing University of Science and Technology
Nanjing, China
Co-Author(s):
Yifei He
School of Computer Science and Technology, Nanjing University of Science and Technology
Nanjing, China
School of Computer Science and Technology, Nanjing University of Science and Technology
Nanjing, China
Tao Zhou
School of Computer Science and Technology, Nanjing University of Science and Technology
Nanjing, China
School of Computer Science and Technology, Nanjing University of Science and Technology
Nanjing, China
Xiaoming Liu
Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and
Wuhan, China
Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and
Wuhan, China
Introduction:
The vertical orbitofrontal fascicles (VOFF) is a critical association pathway in white matter (WM)[1]–[4] for coordinating sense, emotion, and memory, which connects the lateral orbitofrontal cortex (LOF) and the superior frontal cortex (SF). It is related to multifunctional coordination processing and is the only vertical white matter pathway connecting lateral orbitofrontal and superior frontal cortices. While the WM pathways that involve LOF (e.g., superior occipitofrontal fascicles) or SF (e.g., uncinate fascicles (UF)) have been well investigated in previous studies, detailed delineation of the anatomical pathway connecting the two cortices is non-existent. In this work, we investigate the organization and structure of the connection between LOF and SF via diffusion tractography[5]–[7] and confirm for the first time the existence of a vertical connection, i.e., VOFF. To date, VOFF is a poorly understood anatomical structure that potentially involves high-order cognition, such as decision-making[8].
The VOFF is one of the three vertical pathways in the human brain[9] and extends between the superior and inferior frontal cortices (Fig. 1a), discovered by Lamendella and Geschwind[10]–[12]. Understanding the anatomical structure of vertical VOFF will improve our knowledge of the prefrontal lobe's role in executive functions.
The VOFF is one of the three vertical pathways in the human brain[9] and extends between the superior and inferior frontal cortices (Fig. 1a), discovered by Lamendella and Geschwind[10]–[12]. Understanding the anatomical structure of vertical VOFF will improve our knowledge of the prefrontal lobe's role in executive functions.
Methods:
We investigated the vertical VOFF using the anatomical MRI and diffusion MRI (dMRI) data of 100 unrelated subjects from HCP Young Adults[13]. All diffusion-weighted images were corrected for eddy-current and susceptibility distortions.
We performed whole-brain tractography using asymmetric fiber orientation distribution functions (AFODFs) to capture better complex axonal configurations, such as bending, fanning, and crossing, and to mitigate gyral bias for better cortico-cortical connectivity[5]–[7]. Generated by successively following the local directions determined by the AFODFs, whole-brain tractography performed with 64 random seeds per voxel resulted in approximately 10 million streamlines. The fiber streamlines connections between (i) SF and medial-orbitofrontal cortex (MOF) and (ii) SF and LOF were retained for subsequent processing. We removed standard false-positive bundles and commissural bundles. An unsupervised bilateral fiber clustering was then implemented to group the streamlines into K fiber clusters (we set K=30)[14]. We semi-automatically extracted the vertical VOFF and similar structures (Fig. 2b) from these fiber clusters based on the Kahle Human Anatomy Atlas[3].
We performed whole-brain tractography using asymmetric fiber orientation distribution functions (AFODFs) to capture better complex axonal configurations, such as bending, fanning, and crossing, and to mitigate gyral bias for better cortico-cortical connectivity[5]–[7]. Generated by successively following the local directions determined by the AFODFs, whole-brain tractography performed with 64 random seeds per voxel resulted in approximately 10 million streamlines. The fiber streamlines connections between (i) SF and medial-orbitofrontal cortex (MOF) and (ii) SF and LOF were retained for subsequent processing. We removed standard false-positive bundles and commissural bundles. An unsupervised bilateral fiber clustering was then implemented to group the streamlines into K fiber clusters (we set K=30)[14]. We semi-automatically extracted the vertical VOFF and similar structures (Fig. 2b) from these fiber clusters based on the Kahle Human Anatomy Atlas[3].
Results:
The vertical VOFF and five similar structures near the vertical VOFF were detected in all subjects (100%). Fig. 1c confirms the existence of VOFF and indicates that it is orthogonal to the superior occipitofrontal fascicles (SOFF) and UF. Fig. 1d suggests that the vertical VOFF is approximately tangent to the cingulate bundle (CB). These observations form guidance for the identification of the vertical VOFF from among the whole-brain streamlines. Fig. 2 (b-2 to b-6) shows some WM pathways adjacent to the vertical VOFF, indicating that the geometries of WM pathways connecting the SF to the different parts of the orbitofrontal cortex are different. The vertical VOFF is more likely to connect the SF and the LOF, but not the MOF.
Conclusions:
We unveiled an association pathway called vertical orbitofrontal fascicles (VOFF), which is likely to subserve the communication between the lateral orbitofrontal and superior frontal cortices. Using diffusion tractography, we showed that the VOFF can be identified consistently across the population. The preliminary shape analysis revealed distinctive tissue properties in the vertical VOFF compared to neighboring pathways, indicating potential cytoarchitectonic and functional transitions in the lateral orbitofrontal cortex. Future research needs to identify the underlying changes in VOFF across lifespans further.
Neuroanatomy, Physiology, Metabolism and Neurotransmission:
White Matter Anatomy, Fiber Pathways and Connectivity 1
Neuroanatomy Other 2
Neuroinformatics and Data Sharing:
Brain Atlases
Novel Imaging Acquisition Methods:
Diffusion MRI
Keywords:
Computational Neuroscience
Tractography
White Matter
WHITE MATTER IMAGING - DTI, HARDI, DSI, ETC
1|2Indicates the priority used for review
Provide references using author date format
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