My dataset consist of 1 group and one session per subject. Session consists of 6 runs.
There are 6 different conditions: A, B, C, D, AB, CD
My problem is: this conditions are represented in pairs per run e.g.
run-01: condition A and B
run-02 condition C and D
run-03 condition AB and CD
run-01: condition AB and CD
run-02 condition A and B
run-03 condition C and D
Therefore some conditions are never represented in the same run.
Is it possible to do a group level analysis and to estimate contrasts for A > AB, or D > CD?
I mean, the effect/activations are probably influenced by the run itself, aren’t they?