I am a PH.D. candidate in Beijing Normal University, China. My research interest  mainly focuses on applying multivariate pattern analysis with multi-modal MRI analysis to uncover the individual differences of human brain.

I have calculated the whole-brain WMV map and going to do group comparisons.

However, I was confused that should we regress whole brain size or the total WMV size when doing VBM analysis?

If we should regress the whole brain size, why should we consider total size of GMV when analyzing WMV?

Any suggestions will be appreciated.

Thanks in advance.

Best wishes 

Zaixu