Hi,
After reading the Reference and documentations, I am still unsure about how
to evaluate numbers from probtarckx when using masks (multiple voxels).
In all cases, probtrackx samples 5000 times.
1) According to the paper, for a single voxel seed tracking, the output map
gives you - the connectivity value or the number of samples passed through
that seed and other voxels. Does that mean the probability would be
(value/5000) for a voxel having connection with that single seed voxel?
2) If using a seed mask (multiple voxels), then the probability of a voxel
having connection with ANY voxel in the seed mask would be (value/sum of
values of each voxel in that seed mask)?
3) If using a seed mask along with a waypoint mask and a termination mask...
a) Does the value now indicate - the number of samples passing through both
the seed mask and the waypoint mask AND terminate in the termination mask?
b) The probability of a voxel in the waypoint mask connecting to any voxel
in the seed mask would still be (value/ sum of values of each voxel in the
seed mask)?
In other words, values in the termination mask do not matter because it's
only used to stop the tracking pathways but not affecting any of the numbers?
Any comments or help would be greatly appreciated.
Sorry if I did not state the questions very well... I can try if you would
like me to clarify more. thanks again.
Yu-Chin
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