i am just reading a review :Default-mode brain dysfunction in mental disorders: A systematic review.  in this article the REST software is mentioned as a methods and measurement models to investigate the DMN.it is said:
  "The assessment of resting brain networks using the BOLD
response may be achieved through a number of methods. Two of
which, region-of-interest (ROI) seed-based correlation approaches
and ICA, are most commonly employed in the literature."