Dear Saad
Thank you very much.
With the option of the classification targets, if one side of a
streamline sample ends in target region A,while the other side ends in
target region B, which file will record this streamline
sample.Seed_to_targetA.nii,or Seed_to_targetB.nii?
Best Regards,
Suyu
2012/4/17 Saad Jbabdi <[log in to unmask]>
> Hi
>
> Both sides of a streamline sample are considered as the same sample, i.e.
> only counted once.
>
> Saad
>
>
>
> On 16 Apr 2012, at 12:04, ÖÙËÕÓñ wrote:
>
>
> Dear Saad,
>
>
> Thank you very much for your replay.
>
>
> Yes, fdt_paths and seeds_to_targets indeed contain difference
> information. Fdt_path containing the output connectivity distribution
> represents the number of samples that from all voxels of the seed mask to
> one voxel.
>
>
> I want to know if this difference is due to the differences in count
> methods.
>
>
> As the fact that fsl track a fiber in 2 directions and I want to know
> if one sample will be counted twice in fdt_path or only once ? And how
> about in the situation of seeds_to_target? For example,if two end points of
> the one fiber terminate in one region, the fiber will be considered as once
> or twice? And how about two end points of one fiber terminated in two
> regions?
>
>
> Best Regards and Thank you in advance
>
>
> Suyu
>
>
> 2012/4/14 Saad Jbabdi <[log in to unmask]>
>
>> Hi - fdt_paths and seeds_to_targets do not contain the same information,
>> that is why your results are not the same.
>> In your case you want to use method1.
>> Have a look at the probtrackx doc where these files are described.
>>
>> Cheers
>> Saad
>>
>>
>> On 11 Apr 2012, at 02:38, Zhong Suyu wrote:
>>
>> > Dear FSL experts:
>> >
>> > I am freshman of FSL.
>> >
>> > I am trying to do whole brain probabilistic tractography and to
>> calculate connection probabilities between a set of N regions.
>> > First, I set one of the ROIs(i=1....N) as the seed mask , set all the
>> rest ROIs as the stop mask(--stop), and set a list of targets that include
>> all ROIs. And do protrackx. As a result,I got NXN seed(m)_to_<targets>(n)
>> (m,n=1....N) files and N fdt_path files (each fdt_path contain the
>> connectivity distribution from one of the N seed mask ROIs to the rest ROIs
>> ).
>> > And then I determine the NxN connections in two ways: the fist way is
>> sum the value of each voxel within each seed(m)_to_<targets>(n) file as the
>> mth row and the nth column element of the connection. The second way is to
>> use the fdt_path and fslstats command.
>> >
>> > I want to know if the results from the two methods are same. In my
>> experiment, I got the different results.
>> > I find the number of samples got from seed_to_<target> is less than the
>> one from fdt_path. Is it right? If yes, why the numbers are not the same?
>> >
>> >
>> > Thank you in advance!
>> >
>> > Suyu
>> >
>>
>> --
>> Saad Jbabdi
>> University of Oxford, FMRIB Centre
>>
>> JR Hospital, Headington, OX3 9DU, UK
>> (+44)1865-222466 (fax 717)
>> www.fmrib.ox.ac.uk/~saad
>>
>
>
> --
> Saad Jbabdi
> University of Oxford, FMRIB Centre
>
> JR Hospital, Headington, OX3 9DU, UK
> (+44)1865-222466 (fax 717)
> www.fmrib.ox.ac.uk/~saad
>
>
>
>
>
>
>
>
>
>
>
