Dear Freesurfer experts,

 

I've just finished running a qdec analysis of a comparison of cortical thickness between controls and patients with 2 covariates and found a strange result. 

When i set the threshold at FDR some clusters appear in red which are the corrected results from my analysis.

However the rest of the cortex acquires a grey homogeneous colour that seems strange.

 

When i check the thresholds in qdec i found that they were set from 100 to -100...

Any ideas why this happened?

 

Afterwards i did the mri_glmfit simulations with these results from qdec and saw that the summary cluster table indicated a single bilateral cluster of more than 70 000 mm size, as if the program considered the homogenous grey colour as a significant result between groups.

 

Any help would be greatly appreciated.

 

Best, Joana