Dear FSL experts,
I am interested in running probabilistic tractography between some brain regions of interest (ROI1, ROI2, ROI3, ROI4), separately for each pair.
I intended to run probtrackx2 for each possible pair including each two ROIs to the "multiple masks" option.
In order to run this I created these text files as mask lists:
ROI1_ROI2.txt
/User/path/ROI1.nii
/User/path/ROI2.nii
ROI1_ROI3.txt
/User/path/ROI1.nii
/User/path/ROI3.nii
ROI2_ROI3.txt
/User/path/ROI2.nii
/User/path/ROI3.nii etc.
Running these results in getting waytotal files containing two numbers, the first number is streamlines from ROI1 reaching ROI2 and the second number is streamlines from ROI2 reaching ROI1.
I noticed that in some articles some people ran both ROI1_ROI2 AND ROI2_ROI1 and then averaged the streamline numbers from the two waytotal files (average for ROI1 and ROI2).
My questions:
In you opinion, is this practice a better, more complete way to get the connectivity between ROI1 and ROI2, or is it redundant given that ROI1_ROI2 tractography already gives streamline counts beginning both in ROI and ROI2?
Thank you.
Best,
Nasia M.
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