Previously I asked this question (but no one answered), but later I got a new idea, so here I re-describe it briefly and hope some expert could help.
Suppose I have a paradigm: a 5 s working memory period (WP) followed by a 4 s decision period (DP) (this is decision task. there is a non-decision control task that did not require working memory or decision). My whole-brain analysis revealed activation in brain regions A and B during WP and DP, respectively.
My aim is to examine if A interacts with B to drive the decision process. To test my hypothesis, what kind of analysis can I perform?
My idea is to extract the trial-wise BOLD signal in A during WP, and then use this value as a parametric modulator for the main regressor that identifies B during DP, to see if the response in A during WP is parametrically associated with the response in B during DP. Does this idea make sense?