Dear SPM experts,
There are two types of stimuli (face vs. house) in my experiment and each of which had four levels (linear) of visual complexity. I want to see which brain regions activate increasingly with the four levels of complexity in each of the stimuli and whether there are overlapped activations for the effect of the visual complexity of each type of stimuli. My question is how to set up second level analysis. There are two possible ways to do that
1-a. at first level, create a con image for each type of stimulus (face and house) and for each subject (e.g., 10 subjects) in which the contrast weighting of [-1 -1/3 1/3 1] are set for the four levels
1-b. at second level, submit those con images into two-way ANOVA design in which there are two con images for ten subjects
2-a. at first level, create four con image for each level of complexity in each type of stimulus (face and house) and for each subject (e.g., 10 subjects)
2-b. at second level, submit those con images into a full factorial design in which there are eight (4 level (visual complexity) x 2 type of stimuli (face vs. house)) con images for ten subject into a full factorial analysis in which factor one (face) has four levels and factor two (house) has four levels.
Could someone tell me which way is correct and why. Thanks!
Sincerely,
Veda
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