wang,

qdec doesnt yet support analysis of subcortical structures in the way i think you were expecting. that is, currently only surface measures (by default thickness), is selectable as the independent variable. a subcort volume is not yet selectable (its output results would be bar charts, not a surface display). you can do a subcortical volume analysis by working with the aseg.stats file directly in some stats program (or mri_glmfit).

so if a particular volume measure is selected via the stats import option, and it is selected as a possible factor, and that factor is selected as a regressor in the Design window, then when an analysis is run, it is entirely possible (and very likely) that there is no change in thickness value given a particular subcortical volume. the one exception i have seen for this is hippocampal volume, which does have an effect on cortical thickness between controls and AD patients.

n.

On Wed, 2011-05-04 at 11:18 +0800, 汪贵宏 wrote:

Dear freesurfer experts:

 I had processed my data with recon-all, and also ,I had compared

the cortical thickness difference between the con and pat with qdec .however,when i I try to compare the sub-cortical volume difference between con and pat ,the results were the same as the thickness,even in Analysis Results window,the option is not changed,as the "Does the average thickness differ between con and pat?" So, I have no idea about it,because I chose the ASEG.VOLUME in the "Stats Data Import" window.

In addition ,I wander whether the volume differ comparison is processed based on ROI or vertex?

Did anyone can help me with any suggestion.

thank you wang

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