Hi Ahmad,
Since no one else has answered yet, I thought I'd give it a try.
> In order to find the process of interest (PI) - i.e., auditory
> recognition - which is found in A1 only, - Can I use conjunction
> (A1-C2) and (A1-C1) for this purpose?
I believe you can't really use a conjunction for this purpose since
the contrasts are not orthogonal (A1 is the same in both contrasts).
It sounds like what you'd like to identify are those areas reliably
activated in A1 relative to your two baseline conditions. If so, then
one thing you can do is compute the A1-C1 contrast and (inclusive)
mask it with the A1-C2 contrast (since that is presumably less
restrictive). This would restrict the areas of interest to those
which were more active in A1 than in C1 and C2.
There are probably more sophisticated statistical methods for doing
this and hopefully the more knowledgable members of the list will add
their $0.02.
Cheers,
- Joe
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Joseph Devlin, PhD * email: [log in to unmask]
Center for Speech and Language * [log in to unmask]
Experimental Psychology Department *
University of Cambridge * Phone: 01223 766 454
Cambridge, CB2 3EB * Fax: 01223 766 452
England *
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