Are the grey matter segments (m0wrp1 and m0wp1) obtained with VBM8, using the 'high-dimensional Dartel' and 'low-dimensional SPM default' options for spatial normalization respectively, in the same space? For the same group of subjects I produced these two different GM segments but found that my Marina's ROI masks overlay better on m0wp1 compared to m0wrp1. So, for the m0wrp1, do I need to normalize or coregister the Marina's ROI masks with a dartel template first, such as the avgT1_Dartel_IXI550_MNI152 or Template_6_IXI550_MNI152 ?
Also, may I interpret the mean intensity (e.g. 0.67) extracted from a ROI on modulated grey matter image (I used the REX toolbox to do mean extraction) as the probability of finding GM in this ROI? If so, does a higher probability mean a greater amount of GM volume in the ROI?
Thanks for your advice!