Hi Klaas and other experts,
when defining a VOI, SPM asks whether we want to "adjust data for...
effects of interest" and several mails on this list indicate that it is important to
do this when defining a VOI for DCM.
e.g.
http://www.jiscmail.ac.uk/cgi-bin/wa.exe?A2=ind05&L=SPM&P=R580878&I=-3
Our question is: in the situation
where you have several regressors in your design matrix, but not all of
them are included in your DCM model, should you correct for effects of
interest across ALL regressors, or only those which you want to include?
Similarly, given that the VOI is defined on a session-by-session basis,
should you correct for effects of interest only for that single session,
or for all the sessions in your design matrix?
And what are the various implications and assumptions of making these
different types of correction?
with thanks
Chris Summerfield and Julie Grezes
Christopher Summerfield
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