Hi SPMers,
Herein I have another question about the 2nd level analysis in SPM5.
In my experiment, 14 subjects received 2 fMRI scannings
(low-temperature vs. high-temperature stimulus, 10 stimuli per scan,
10 seconds per stimulus), and I want to analyze the difference in
brain activations during the early (first 5 s) and late (final 5 s)
phase of stimulation for the 2 stimulus temperatures.
I'm struggling with running a 2(low vs. high temperatures)-2(early vs.
late phase of stimulation) repeated-measures ANOVA in SPM5.
I used the "full factorial" 2nd level analysis in SPM, and the item
"Independent" is designated as "No".
The procedures are as follows:
I set 2 factors: Temperature (2 levels: low vs. high) and Phase (2
levels: early vs. late phases).
The 4 cells are designated in order as:
1-1 (cell 1) = low-early
1-2 (cell 2) = low-late
2-1 (cell 3) = high-early
2-2 (cell 4) = high-late
I put the 4 t maps (low-early, low-late, high-early, high-late) from
each subject into the 4 cells by order.
1. To get the map of "high temperature > low temperature", I used the
contrast -1 -1 1 1 (0.05 FDR).
2. To get the map of "low temperature > low temperature", I used the
contrast 1 1 -1 -1 (0.05 FDR).
3. To know which regions showed "high temperature > low temperature"
during the early phase of stimulation, I used the contrast -1 0 1 0.
4. To know which regions showed "high temperature > low temperature"
during the late phase of stimulation, I used the contrast 0 -1 0 1.
5. To know which regions showed "low temperature > high temperature"
during the early phase of stimulation, I used the contrast 1 0 -1 0.
6. To know which regions showed "low temperature > high temperature"
during the late phase of stimulation, I used the contrast 0 1 0 -1.
Am I doing right?
Does SPM5 allow the analyses of repeated-measures ANOVA?
I'd appreciate for any help.
Thanks
Dr. Tseng
