I am trying to find a way to test changes over time
using a repeated measure ANOVA. We acquired 40-minute
(4, 10-minute runs) fMRI scans of 20 participants
performing a working memory task. The 4 runs performed
by each participant require me to use repeated measure
I am trying to find a way to move beyond the general
indication of the F-test that there is one run (at
least) that has stronger/weaker activation than the
average activation. Specifically, I would like to see
if the activation across the 4 runs fits a positive or
a negative linear and quadratic functions. My
1. How do I create a contrast that reflects a linear
2. How do I create a contrast that reflects a
3. If it is not possible, is my only option to follow
up with specific paired T-tests between runs?
4. When I run the F-contrast, I get questions about
non-sphericity and correlations among runs. Doesn't
specifying a within-subject model assume that?
Any help would be greatly appreciated!
Be a better friend, newshound, and
know-it-all with Yahoo! Mobile. Try it now. http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ