Dear FS team:
I want to ask for some advice on how to extract the values
of pial surface area. I use QDEC to perform a surface-based F-test. The
measurement is area.pial and the smoothing is 10 in QDEC. After correction,
there is one significant cluster with
size of ~760 mm^2. The problem comes when I want to extract the measure from each participant, so that I can plot the group means. Currently I used the
values from the "cache.th20.neg.y.ocn.dat" file, but all the group
means varies between 0.7-1.0 in magnitude. I believe the unit is mm^2, because
this is pial surface area. But is 0.7-1.0 mm^2 too small? What is the correct
way to extract surface area from this signficant cluster, so I can plot the pattern of
group differences in a bar graph?
Another question is the validity of surface-based
analysis on pial or WM surface area. I found most FS publications focus on the
thickness, but not the surface area. From your perspective, is the surface area as valid as the thickness
measure?
Many thanks in advance
Karl