I am conducting surface group analyses and would like to acquire exact p values. 

The FreeSurfer manual notes that the number listed after the peak coordinates and the vertex # is a "significance value," and that the "significance in this display is a -log(10)p value, and not a straight p value."

However, if I log this number the "p value" I calculate is not significant (e.g., log(5.68) = .75) so I don't believe I am interpreting their description correctly.

Could you please advise on how to acquire exact p values? 

Thank you for your time.