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Dear freesurfer community,

I have been trying to experiment a bit with the dmri_pathstats command that 
TRACULA uses to compute tract statistics. I read previously that one could 
change the default threshold value that stats are computed with by using the 
"--pthr .##" option. (I was curious about using this since I often run into the 
peculiar problem of some tracks, e.g. forceps major/minor, having mostly normal 
looking path.pd maps, with a few voxels having unusually high values, thus 
potentially biasing results. These tracks are often set at abnormally high 
thresholds when visualizing the tracks. e.g. a forceps major normally has a 
threshold [30,45], while some may be thresholded as high 100 or 150, making the 
tract look problematic).

I experimented by running the dmri_pathstats command with a few different 
values for "--pthr .##":

  *   --pthr .01
  *   --pthr .05
  *   --pthr .10
  *   --pthr .20
  *   --pthr .80
  *   --pthr 1.00

However, the outputted "pathstats.overall.txt" and "pathstats.byvoxel.txt" 
files are all identical. Suspecting a potential bug, I did a few more tests, 
with values such as:

  *   --pthr 2.0
  *   --pthr 100
  *   --pthr 50000000000000
  *   --pthr hi
  *   --pthr goodbye
  *   --pthr

Interestingly, all of the outputted "pathstats.overall.txt" and 
"pathstats.byvoxel.txt" files were all identical to the previous six tests. The 
program does not return an error message either. Is this a potential bug? Or 
was the "--pthr" functionality removed from dmri_pathstats?

Incidentally, I am using freesurfer version 5.3.0. Maybe this was updated in a 
further release?

Thank you for any clarification!

Sincerely,

Adam Schadler

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