Dear FSL experts
I have a question how to set up the model for a task fMRI experiment
the task is relatively complex (domain of personality)
in short, a visual stimulus is presented, and the participants have to provide an answer using a button
the stimuli has 4 characteristics that can be combined in various ways
1 consistent vs inconsistent
2 self vs other
3 matching vs mismatching
4 avatar vs flash
so each single stimulus is a combination of the 4 variants
for example :
consistent - self - matching - avatar
or
inconsistent - self - matching - avatar ...
we have 25 participants x 4 runs each (each run has the same stimuli, but in different order). We do not have each possible permutation, but 12 conditions
so, now the question
At the first level, we have 2 options
1: define 12 conditions (e.g. consistent - self - matching - avatar ; inconsistent - self - matching - avatar …)
2: define only 4 variants (consistent yes/no - self yes/no - matching yes/no - avatar yes/no)
What would you do ?
At the higher level, we want to do quite a number of contrasts
e.g. self-consistent-avatar VERSUS self-consistent-flash
However, the difference between the stimuli is very small, and I do not expect to have a lot of activation
Therefore, I also would like to see ALL self vs ALL other, ALL consistent vs ALL inconsistent ... (the problem here is that for one of those pairs, there are 2 times more stimuli in one variant)
How would you model this ?
Thanks a lot for your help !
Sven
########################################################################
To unsubscribe from the FSL list, click the following link:
https://www.jiscmail.ac.uk/cgi-bin/WA-JISC.exe?SUBED1=FSL&A=1
This message was issued to members of www.jiscmail.ac.uk/FSL, a mailing list hosted by www.jiscmail.ac.uk, terms & conditions are available at https://www.jiscmail.ac.uk/policyandsecurity/
|