If you want p-values for the clusters, then you need to run a simulation (mri_glmfit-sim). I think QDEC creates a script to do it.

doug

Rosa Steimke wrote:

dear freesurfer experts. i have another problem in generating output useing mr_surfcluster command.

i was wondering how to generate an output with the significant clusters from my qdec analysis i learnd that i have to use the mri_surfcluster command and use the sig.mgh file from my qdec. however i am very uncertain about how to apply the explanation (from freesurfer wiki) of the mri_surfcluster commands to the sig.mgh. i got the error message that the --sum command cannot be used for the sig.mgh file and i dont understand whether i have to apply more commands (besids thresholding, subjects and such) to generate the and output that gives me the size, significant values and coordinates of each of the clusters i can see in qdec.

thanks for your help. rosa