Dear Dr Fornito, thanks for sharing this nice connectivity tool. I have a general question about the comparability of your approach with the standard PPI or the generalized PPI (http://www.nitrc.org/projects/gppi/). I understand that with the latter you create an asymmetric connectivity matrix, which is not always easy to interpret in terms of functional connectivity.

I ran both a cPPI and a gPPI in several subjects for a set of seeds, and was expecting to get connectivity values that were well correlated between the two methods. However what I observe is that within a given subject the values are rather anticorrelated, meaning that high cPPI correlation values are usually associated with lower gPPI beta estimates. 

I ran both analyses using the standard scripts, so I hope I did not do anything wrong, and I would be glad to hear your opinion on that.

David Coynel