Hi;
In a block fmri study i have one condition (B)and a rest condition (A).
I used linear parametric specification to model the condition B.
If i understand this correctly, this means that i used two basis functions
to model condition B ( constant=zero order, and linear function=first order).
I did not specify expilicitly the rest condition (just entered into spm99
that i have one condition trial 1, which is equivalent to condition B)
My questions are ,
How does SPM99 represent the rest condition??
Does it assume that the rest condition A is modeled by a two basis
functions similar to condition B ??
Does it assume that the beta value corresponding to the first order basis
of condition A is zero??
More specifically? If I use a T-test
what does the following contrasts mean
1 0 (does this contrast compare the zero order between B & A)
0 1 (does this contrast compare the first order between B & A)
I think im asking the same question in different ways. I just want to make
sure that i'm understanding this.
what part of spm99 takes care of modeling the rest condition if it is not
specified explicitly?
Many thanks;
saaussan
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