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bioRxiv · 10.1101/409268

On the interpretation of tractography-based parcellations

Clayden, J.·Thomas, D. L.·Kraskov, A.
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Abstract

Connectivity-based parcellation of subcortical structures using diffusion tractography is now a common paradigm in neuroscience. These analyses often imply voxel-level specificity of connectivity, and the formation of compact, spatially coherent clusters is often taken as strong imaging-based evidence for anatomically distinct subnuclei in an individual. In this study, we demonstrate that internal structure in diffusion anisotropy is not necessary for a plausible parcellation to be obtained, by spatially permuting diffusion parameters within the thalami and repeating the parcellation. Moreover, we show that, in a winner-takes-all paradigm, most voxels receive the same label before and after this shuffling process--a finding that is stable across image acquisitions and tractography algorithms. We therefore suggest that such parcellations should be interpreted with caution.

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Clayden, J., Thomas, D. L., Kraskov, A.. 2018-09-06. On the interpretation of tractography-based parcellations. https://doi.org/10.1101/409268

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