Dear Alfonso,

Thank you for all the support offered here!
We have used CONN to investigate fALFF and SBC in four different groups: hyperphagic MDD, hypophagic MDD, euphagic MDD and healthy controls (HC). Because data were collected in four sites, we included site as covariates as well as sex (due to difference between groups for sex).
We received a request from a reviewer to explore sex in a moderation analyses given sex differences between groups, so we would like to test the interaction group*sex for fALFF and SBC in our sample using CONN.
We saw a post in which you explain this process using continuous variables (https://www.nitrc.org/forum/forum.php?th...), but it is not very clear for us how to do that with categorial variables. We thought of adding separate 2nd-level covariates to setup including each group and each group separated by males and females (e.g., hyper females, hyper males, hypo females, hypo males, euphagic females, euphagic males, HC females, HC males) and set up the between-subject contrast in 2nd-level results to explore interaction. Would this be a way to explore this interaction? How exactly could we set up the main effect of group and group * sex interaction?

Thank you so much!

Mayron