Dear FSL experts,
I have used FIRST and FAST to compute volumes of various sub-cortical nuclei, grey matter and white matter. Volumes were compared between two well matched subject groups and no statistical differences were found. I also used VBM to analyse potential grey matter differences between these groups. When using VBM, significant areas of grey matter loss were observed in a number of sub-cortical nuclei as well as cortical grey matter.
What I would like to know is what exact differences VBM detects in grey matter i.e. does it represent loss of grey matter volume/density? If VBM does detect grey matter loss, is it normal to detect no differences when comparing volumes between groups (i.e. cortical and sub-cortical volumes) and have statistical differences using VBM?
Thank-you for your help,
Matthew Clark
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