Dear SPMers,
Do you know if there are any DMN masks available. I am
interested in exploring group differences within the DMN for my healthy elderly
and Mild Cognitive Impairment groups.
In my experiment, I have a group factor and a repeated
measures factor: working memory load over 3 levels. As an alternative to a DMN
mask, could I use a mask based on task-negative activity averaged across load,
i.e. all activity below implicit baseline (-1 -1 -1)? When I have done this the
task-negative regions show a striking resemblance to the regions of the DMN.
Would it be appropriate to perform a global null conjunction
for both groups for this negative effect t-contrast, save this as a mask and
then test for group differences or group x load interactions in this ROI?
Nicky Kochan
PhD student, School of Psychiatry, University of New South
Wales