Dear Freesurfer experts,

I ran surface based analysis between two groups using PET surfer to study the difference in PET signal between two groups. I followed the same steps as in wiki and everything went fine. To visualize the final statistical maps, I used the command: 

tksurfer fsaverage lh pial -overlay -overlay cache.th20.pos.sig.cluster.mgh

The report "cache.th20.pos.sig.cluster.summary" shows two significant structures (attached figure 1). Looking at the figure from the output of tksurfer (attached figure 2). I see significant results in the frontal lobe.

Please what I am doing wrong?

Your guidance is highly appreciated

John