Dear FSL-experts,
I would like to create functional connectivity matrices for the entire
brain (90 gray matter regions) using probabilistic tractography, but
there are few questions:
- Do the tractography results (substantially) change if gray matter
regions from the atlas (already registered to individual space) may not
exactly touch the adjacent white matter structures? If yes, how is this
resolved?
- Is it valid to reduce the gray matter regions to their boarders (i.e.,
remove inner parts of the region to reduce computation time)?
- I am not sure about the output of matrix1: following the FSL user
guide matrix1 contains 3 columns with column 3 being the streamline
count between the voxels of column 1 and 2, right?
- How is probabilistic tractography interpreted in terms of structural
connectivity? The output gives me the probability that a certain
connection exists (fdt_paths: number of streamlines passing through a
certain voxel) but how is this related to the strength of the
connectivity (especially since the number of streamlines will vary
depending on the size of the seed region)?
Thank you in advance for your help and kind regards,
Andreas
--
Andreas Hahn, MSc PhD
Functional, Molecular & Translational Neuroimaging
Department of Psychiatry and Psychotherapy
Medical University of Vienna, Austria
Phone: +43-1-40400-2320
Email: [log in to unmask]
Web: http://www.meduniwien.ac.at/neuroimaging/
|