Dear SPM Experts,
I am analyzing a small, longitudinal fmri dataset that has 4 separate runs/conditions, for 6 separate sessions. When I looked at first level individual subject results from the con images within one session, the glass brain was entirely "black." I set the threshold to .9 uncorrected for quickly checking for activity before doing second level analyses.
The 4 bars within the design matrix represent each of the 4 conditions. They should typically be white, but in the example attached, there seems to be gray horizontal bars through the second and fourth conditions. This kind of pattern has happened in a few other subjects across other sessions and in different conditions (i.e. in the 1st condition or 4th condition), and so I can't pinpoint if the problem is systematic in my preprocessing steps.
Is this a problem with estimation?
Thank you in advance!