wang,

i think having the imported roi thickness data in your qdec.table.dat file is confusing you. you should just delete that data from your qdec.table.dat, keeping just 'fsid' and 'addiction' columns. from looking at your analysis (which appears you have done everything right), it is not used anyway, as it appears just the discrete factor 'addiction' was selected in your analysis, which is the right thing to do for a straightforward two-group analysis.

Your display image doesnt show insula, so i cant say whether the effect would survive multiple corrections (there is an option to run this in qdec), but your highlighted vertex has a log-p of -3.7, which is a p of 0.002 for that vertex.

The roi data that you imported is the average thickness value for that roi for that subject prior to any kind of statistical analysis (freesurfer recon-all automatically creates rois in the cortical parcellation stage). generally you would use those outside of freesurfer in another analysis package. you can import them into qdec and select them in an analysis if you wanted to conduct some rather unusual analyses, like asking does the thickness of the roi 'entorhinal' affect overall cortical thickness? (which can be a good question for aging research, but in general is kind of unusual).

n.

On Mon, 2011-02-28 at 17:19 +0800, 汪贵宏 wrote:

Dear all,

I try to analysis the thickness difference between the patient vs. control for several days, but I fail to explain the results.Although I had read the wiki on the website,it not works for me. Here,I list the procedures which I took for my study,I really hope somebody can help me. My research is to analysis the thickness difference between the control vs.patient which are addicted on the internet.

Firstly,as the papers says,FREESURFER divided each cortex hemisphere into 33 areas,but why did there has only one thickness value per area?there is the thickness information for all of controls and patients in the first file which I add in the appendix. Secondly,why did the thicknesses are not in the same value for the same area between the qdec.table.dat (in the first appendix)and which in the first picture in the appendix below? Thirdly,the detail steps I took in the qdec are also list in the appendix pictures,is it right?

Thanks a lot.

Sincerely, wang

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