Tckgen seeding options

Hi all,

I’m doing some tests with the seeding options in tckgen. First I used the -seed_dynamic and it worked OK, then I wanted to compare the outputs between seed_image and seed_sphere. The second one is faster than the first one, but my doubt is why, if I’m setting a seed region (in either case), do I obtain some tracks that born in other regions? I thought that I only could obtain tracks from the seeding point. I attached a screenshot to make it clear.

In the next figure you can see: the T1 image, the roi image (with colourmap hot), the node image and the connectome whose tracts were generated with the seed_sphere option.


I’m not sure what you mean by born here, but maybe the confusion is due to the fact that tckgen performs bidirectional tracking by default? So it’ll track one way from the seed point, then come back to it and track the opposite direction too. So the result is a streamline that connects between regions outside of the seed ROI. Is this the problem? You can disable this with the option -unidirectional if you need to.