Hi
When you use network mode with two ROIs, probtrackx internally does the same thing as you would do when you were running probtrackx twice, swapping seed and waypoint. The only difference is that it doesn't reload the bedpostx samples. Therefore, it shouldn't make a difference to what you do with the waytotal.
Saad
On 30 Jan 2013, at 19:32, Anna Slagle wrote:
> Hello,
>
> In the past, we have run tractography twice, once from roi1 to roi2 and once from roi2 to roi1, in seed to target mode. We then used a percentage of each waytotal to threshold the fdt_paths before combining the two directions.
>
> We are now attempting to use network mode with both roi1 and roi2 as seeds in an effort to simplify (half as many runs, no need to combine them). I have two questions regarding this:
> Have people obtained better results using network mode rather than performing two runs in different directions and combining them or are the two methods fairly comparable?
> Because the network mode waytotal now includes two values, how do you suggest we go about the thresholding? Do we add the two values and threshold as a percentage of the total?
>
> Thank you for your help,
> Anna
>
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> Anna Slagle
> Post-Baccaulaureate IRTA
> Unit on Multimodal Imaging Genetics (UMIG)
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--
Saad Jbabdi
University of Oxford, FMRIB Centre
JR Hospital, Headington, OX3 9DU, UK
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www.fmrib.ox.ac.uk/~saad
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