Dear CONN Users,

I would greatly appreciate your input on interpreting a between conditions contrast using gPPI. The study is a block design motor task with four conditions (fixation, easy, medium, hard). All task blocks are modeled in the gPPI except for the fixation. What would a significant result in a between conditions contrast between the easy and hard tasks tell us? 

My understanding is that this means in the hard task the seed-to-result connectivity is sigificantly modulated by the task beyond the "main effects". In other words, these connections are changed beyond a mere change from fixation-to-task, and is thus likely caused from the increased difficulty. This is an important distinction, because I am hoping to isolate dynamic changes in connectivity as a function of difficulty (i.e compensation related changes). Please let me know if this interpretation is correct, or how it can be corrected.

Sincerely,

David