Hi George,
If you're using modulation (which most VBM folk recommend), then the
mwc* images should have the same volume as the native c* images, and
so yes, I think if you would usually control for ICV then you should
still do so with the modulated normalised images.
If using unmodulated normalised images, then you're right, overall
brain sizes will have been roughly equalised, so you probably don't
need to control for ICV, though it can be hard to tell quite what
unmodulated images are testing for. See e.g. John's wiki:
http://en.wikibooks.org/wiki/SPM-VBM
Best,
Ged.
George P Thomas Jr wrote:
> Hello all,
>
> Is it proper to control for intracranial volume/head size when analyzing
> normalized images? It seems to me that the normalization (optimized VBM
> in our case) would eliminate the need to control for ICV.
>
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