Dear all,
We are conducting a VBM analysis (using the VBM8 toolbox) and decided to use a ROI approach. We used Marsbar scripts to extract individual mean grey matter values for our ROIs.
But what exactly represent this value? I initially thought it would extract the mean grey matter volume, but the numbers I get do not seem to confirm that (seems to be in a 0-1 range). Does it rather represent the grey matter density or concentration within the ROI mask? What would be the unit, % of grey matter?
Thanks for your time.
Cheers,
Yann
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