Hi all,
I apologize if this question has previously been answered... it did not
seem to be.
I have an fMRI study where participants perform a task with multiple
conditions (e.g., positive stimuli, neutral stimuli), each participant
is scanned twice (weeks apart) based on another within-subjects
variable, and there are 2 groups of participants.
To do a mixed analysis, I COULD create contrasts such as "positive
stimuli at scan 1" - "positive stimuli at scan 2" by going across the
sessions, and then use those contrasts for a between-groups analysis. Is
this type of comparison across scan dates allowed?
I would normally be doing an initial contrast to include the baseline
condition (positive-neutral), but then I'm unsure how to use that
contrast in an analysis involving BOTH the between-groups factor and the
two separate scans.
Thank you for your help.
-Zenab Amin
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