Hi. I'm trying to do a between subjects analysis. What it amounts to in
this case is doing an analysis on the mean volumes for each subject. The
problem is that there really isn't any within-subject design (well, it's
"on" all the time for any given subject, which means that you don't get
meaningful t-statistics out of it, and more to the point, feat doesn't
produce cope images) It's pretty clear how to do the high
level analysis, but I don't know how I'm supposed to proceed with the
lower level analysis. Obviously, registration etc is necessary, but I
don't see how I can produce cope images without setting up a design
matrix, and there really isn't a within-subject design in this case. For
now, I've sidesteped the problem by setting up a design that distinguishes
between a short (30s) preliminary rest period and the stimulus, but I'd
rather not do this.
PS I noticed that feat does not apply bet to the structural images by
default for registration, even when the 'bet' button is checked. This was
a source of some confusion for a little while -- it may be a good idea to
consider putting an 'apply bet to structural image' button in the reg
dialog in feat. Seems to make sense since the choice of template appears
to assume that the structural image has been appropriately scalped.
Cheers,
--
Donovan Rebbechi, PhD
Research Associate, Dept of Psychology
Smith Hall #340, 101 Warren Street
Newark NJ 07102
973 353 5440 x240
http://pegasus.rutgers.edu/~elflord
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