Dear SPMers,
I’m analyzing an fMRI n-back task with 3 levels of memory load. The data was
collected in 3 trials (0back vs. 1back / 0back vs. 2back / 0back vs. 3back). 2
groups were measured (drug users and non-users). Each participant was
measured twice (t1 and t2).
Unfortunately each trial consists of only 60 scans (30 0back - 30 1back / 30
0back – 30 2back ……). I think the power might be too low to detect within
and between group differences.
Would it be valid to increase power by merging the 3 trials on the first level?
(3sessions; each 60 scans; t contrast -1 1 -1 1 -1 1)
Thanks in advance,
Ben Becker
Phd. student
University of Cologne
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