Dear SPM-Experts,
I would appreciate any help concerning the following question:
In an event-realted design with 3 different types of stimuli and a parallel
measurement of the reaction times, I aquired data from 14 subjects. I am now
interested to see in which areas the correlation between the BOLD-response
and the reaction time is modulated by the item type. I suppose this is the
interaction of the factor item type and the parametric regressor reaction
time. However, I am unsure about how to specify the design matrix on the
first level and how to combine the data of all subjects at the second
level. In a first step, I entered the three item types [A B C] and the
corresponding reaction times as a parametric regressor to my design matrix
on the first level, yielding a matrix with 7 colums [A Art B Brt C Crt
Const]. I am now unsure on how to proceed to test the above mentioned
interaction.
Thanks in advance,
matthias
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