Dear FS experts,

I are analysing longitudinal data - the difference of the cortical
thickness, surface area and volume between 2 groups (1 and 0) with 2 time
points for each group (0, 1 --all the same time interval: a month).

I followed the page
http://surfer.nmr.mgh.harvard.edu/fswiki/LinearMixedEffectsModels in wiki.
According to experts' advice in the mail-list, I used voxel-wise mixed
model “lhstats = lme_mass_fit_vw(X,[1],Y,ni,lhcortex)” to do analysis. And
I got the result “sig.mgh” (Freesurfer significance map -log10(p-value)).


1. I loaded the “sig.mgh” to do the FDR correction in the qdec tool. When I
press the button of ‘set using FDR ’, the threshold value changes. But the
minimum value in the color bar is a little bit small than the value in the
table. I used the value in the color bar to get the correction result.

Q: Can I do FDR correction like this? And could you give me some more
advices about the correction? And how to do other multiple comparison
correction like Monte Carlo simulation in longitudinal analysis?


2.To get more infotmation about the cluster, I used the cmd
“mri_surfcluster --in sig.mgh --subject fsaverage --surf inflated --hemi lh
–thmin *( minimum value in above FDR correction) --sign abs –annot aparc
–-sum  lh.t.cluster.summary” to generate the set of detected clusters and
their anatomical coordinates.

Q: I want to know if I use the correct command?


3.I saved clusters’ label file manually in qdec tool. Then I use the cmd
"mri_label2label" and "mris_anatomical_stats" to get the value of
thickness. Just like the page:
http://surfer.nmr.mgh.harvard.edu/fswiki/FsTutorial/AnatomicalROI

For area and volume, can I get in the same way? For example, in the stats:#
ColHeaders StructName NumVert SurfArea GrayVol ThickAvg ThickStd MeanCurv
GausCurv FoldInd CurvInd

 lh.1.label     25     19     51   3.044 0.237     0.105     0.068
0      0

I think that the “SurfArea” is the value of area, “GrayVol” is the value of
volume. I wonder that it may be wrong way. In my other GLM analysis, I
found that cortical surface area or volume is not an integer in the file
“…y.ocn.dat”.

Q:Is it right way to get the cluster value? What methods do you recommend
to extract the cluster’s mask and the value within the cluster?


Thank you very much, and looking forward to reply.


Kind regards,

Livia
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