I am trying to calculate whole-brain mean cortical thickness in each individual subject for correction of regional mean thicknesses. 

I see on the wiki that this is recommended to be done by: 

bh.thickness = (lh.thickness X lh.area) + (rh.thickness X rh.area) / (lh.area +rh.area)

In my table I see lh and rh total area but I do not see lh and rh thickness. All I see is mean thicknesses for each region. Are the total rh and lh mean thicknesses supposed to appear in the table? 

Thanks!