> I am interested to find that the correlation between the seed region and the seed
> region (when the seed region was also included in the ROI mask) is 0. I would
> have expected it to be 1. Does it make sense for it to be zero?
There are two new regressors that are added to the PPI analysis: one is the seed region time series, and the other is the interaction regressor. At the seed region, you may find that the correlation with the first regressor is close, if not equal, to 1, but it's not necessarily true with the second one. I'm not so sure which one you're referring to. Regardless, the result at the seed region is not really interesting or interpretable.
Gang
Edited 1 time(s). Last edit at 06/30/2014 10:44AM by Gang.