Hi Aj,
The "connectivity value" in probabilistic tractography from a seed A to a voxel B is defined as the ratio M/N, where M is the number of curves that start from A and go through B and N the total number of curves starting from A. This ratio gives an estimate of the probability of the path of least hindrance to diffusion.
The waytotal file gives you N, the total number of *valid* curves that have started from A (after excluding curves that do not meet exclusion/inclusion criteria). M for each voxel in the image is described in the fdt_paths file. Dividing the two will give path probabilities.
Hope this is clear,
Stam
On 18 Jul 2011, at 09:04, Adil Javed wrote:
> Hi,
> I have generated some data using tractography. The waytotal text file shows a number. Is it more accurate to report that number as connectivity value or an estimate of number of fibers per seed/mask on a plot?
>
> many thanks,
>
> aj
>
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