Dear SPMers,
Two simple questions:
Does the use of optional modulation of non-linear effects only equal the fact of
using total grey matter volume as a covariate in an ANCOVA analysis with
modulated by affine and non-linear effects, or the fact of proportional scaling
to total GM volume (User scaling)?
Furthermore, statistical differences on images modulated by non-linear effets
only are interpreted as "relative volume after correcting for different brain
size". What should we understand by "brain size", this mean TIV as total GM,
total GM+WM volumes, total GM+WM+CSF or any other...?
Although it seems clear and easy, I am a little bit confused.
Thanks in advance.
Alfonso.
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