Hi Michael,
On 23 May 2009, at 21:56, Michael Scheel wrote:
> Hi fsl-gurus,
>
> I have 2 questions re the probtrackx network mode:
>
> Say I have a Region A, B and C defined as masks and enter them as
> Multiple seed masks.
> What connections will be shown to me:
> 1) Any connections between A and B, A and C, B and C or 2) just
> connections that connect all of them, i.e. A-B-C, A-C-B and B-A-C.
neither exactly 1) nor exactly 2).
It will show you an overlay of the following three distributions:
. connections from A that pass through either B or C
. connections from B that pass through either A or C
. connections from C that pass through either A or B
>
>
> Assuming it is (1), and looking only at connections between A and B.
> As I understand from previous discussions, tracking samples are send
> from A to B and B to A and only those that reach their target in
> both conditions 'survive'.
> What I'm wondering about is what are the constraints regarding that:
> Does the sample has to go the exact same voxelway to be found valid
> or is it rather an overlay where voxels survive that were passed
> from either direction, i.e. at least one sample passed from AtoB AND
> BtoA.
It is the latter. A tract survives if it reaches its target,
regardless of the route it has taken.
Cheers,
Saad.
>
>
> Thanks, Michael
>
--
Saad Jbabdi
Oxford University FMRIB Centre
JR Hospital, Headington, OX3 9DU, UK
+44 (0) 1865 222545 (fax 717)
www.fmrib.ox.ac.uk/~saad
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