I've got a question about two-way ANOVA in SPM, more specifically about which 1st-level contrasts to include in the 2nd-level ANOVA. It's a rather basic question but I've seen different approaches, so I'd like to double check which one is more recommended.

In my case, I want to study interactions and main effects in a within-subject experiment using a 2x2 design. Each subject performed the same experimental session several times (repeated measures).

It seems to me that there are 2 different approaches to do it:

1- Create the 2x2 factorial contrasts (conjunction, main effects, and interaction) in the 1st-level analysis (in SPM: fMRI model specification --> Factorial design --> New Factor, and specify the two factors) and then include each of these contrast images across subjects in the 2nd-level analysis (Factorial design specification --> Design --> One-sample t-test).

This is the procedure that I usually do and I find endorsement in https://en.wikibooks.org/wiki/SPM/Group_Analysis and SPM manual.

2- Create simple contrasts in the 1st-level analysis (for example, condition A minus baseline, for every session) (in SPM: fMRI model specification --> Data & Design...) and then include these contrast images in the a Full factorial analysis (Factorial design specification).

So could you please help me to understand which approach is more recommended? If one of them shouldn't be used, could you help me to understand why? Under which conditions the second approach is equivalent to the first one?

Thanks in advance!

Gustavo