Hi Alfonso,
Recently I encountered a similar question (sorry to borrow the following example):
When using "regression" to compare between two groups (HC and AD) the association between FC and performance:
Select: HC, AD, performance_HC, performance_AD, age, gender; Enter contrast: [0 0 1 -1 0 0]
and then I got negative (in blue) connectivity between area A and area B.

Then how to interpret this? the performance difference between groups (HC>AD) could predict the A-B FC difference between groups (AD>HC)?
Hi Yifei,

1) to compare between the two groups (HC and AD) the association between FC and performance:
  Select: HC, AD, performance_HC, performance_HD, age, gender
  Enter contrast: [0 0 1 -1 0 0];