[Freesurfer] watershed values

Hi, I'm trying to adjust the watershed thresholds on a few images, and have a question about the default watershed value.

When I run the skullstrip without specifying a watershed value, the recon-all.log file typically says:

preflooding height equal to 25 percent

Sorting...

T1-weighted MRI image

modification of the preflooding height to 15 percent

I'm guessing this means the program first tried a value of 25%, somehow determined it was too high, and then used a watershed threshold of 15% instead. Is this correct?

Thanks,

-Aaron-

Aaron L. Goldman

Post-Bacc IRTA

Genes, Cognition and Psychosis Program, NIMH

Building 10, Room 3C108

Phone: (301) 435-0944

Email: mailto:aarong@mail.nih.gov aarong@mail.nih.gov