Dear CONN community,

I am currently performing a seed-to-voxel analysis in the CONN toolbox using a block-design fMRI task.

My paradigm consists of alternating active and rest blocks:

1) Active condition: e.g., onsets at 30, 90, ...
2) Rest condition: e.g., onsets at 0, 60, 120, ...

Both conditions are explicitly defined as separate regressors in the first-level design.

My goal is to examine condition-specific differences in seed-to-voxel connectivity between active and rest blocks, i.e., to identify regions showing stronger connectivity with the seed during one condition relative to the other.

My question concerns the appropriate contrast specification:

Should I use

1) 1 -1 (active > rest), or
2) 1 0 (active only)

to test these condition-specific connectivity effects?

More specifically:

1) Does 1 0 reflect connectivity during the active condition relative to implicit baseline, even when rest is explicitly modeled?
2) Is 1 -1 the more appropriate contrast when the goal is to directly compare connectivity between active and rest conditions?

I would greatly appreciate clarification on which contrast is methodologically most appropriate in this scenario.

Best regards,

Laurin