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Hi @all,

I have a feedback paradigm, where people get correct and incorrect feedback
after their answer. There are three sessions for each person and there is a
patient and control group.

I modelled the GLM with the three basis function approach (time and
dispersion derivative). Now I want to test for the difference between
correct and incorrect anwers.

In *Human Brain Function* by Frackowiak & Friston et al. they use an F-test
to test each basis function against zero (see my attached design matrix).
Since I can't tell if the response is positive or negative they say:


> * Because parameters are tested against zero, one would have to
> reconstruct the fitted data and check the positive or negative aspects of
> the response.*


My first question is, how to reconstruct the fitted data and check the
positive and negative aspects of the response within SPM?

And my second question is, if I can use the F-contrast for the 2nd level
statistics to perform a group comparison. Normally I'm using a two-sample
t-test, but I'm not sure if this makes sense when the contrast images are
F-contrasts.

Can anybody help me out here?

greetings

David