Dear SPM users,
I specified a model using Reaction Times as a parametric modulator which is introduced through the pmod structure included in
Conditions Onsets .mat file.
Briefly, I have a 2x2 factorial design (A1 A2 B1 B2) with, for each condition, the RTs entered as a parametric modulator.
From what I understood, if I look at this contrast [1 0 -1 0 -1 0 1 0] , I get the interaction between my 2 factors having covaried out all RT effects.
But I wondered:
1/ What the contrast meant:
[0 1 0 -1 0 -1 0 1 ] what does it mean if a voxel is significantly activated here?
2/ Is my design appropriate to answer the following question: which brain regions are involved in the interaction between my 2 factors precisely by taking into account the impact of RTs (decisional aspect) and precisely not by taking into account the impact of RTs (i.e. decisional aspect) (and precisely NOT by excluding them) ?
Thank you in advance for any help!
Best regards,
Carole
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