Hi Lydia, 

I am also first time using SDM to do a meta analysis. 

I already tried the method you stated above, combined the upper and lower maps separately. I also put them into a new pp folder and want to continue with mean analysis. 

However, I have questions with which parameter files to use? Should I also paste the sdm_nd.txt, sdmpsi_params.xml, sdm_mask.nii.gz and etc files generated from the preprocessing into the new folder? Or is there another way to create those files? 

Now I pasted them to the new folder, and ran the analysis. The first 2 steps can run, but it also creates nothing in the  mi folder in mean analysis, so it reports an error of not be able to find any mi file. 

Or should I do another preprocess for the upper and lower results that I get from the last step? 

I am really confused here, and really hope to get some help. 

Thank you in advance! Hope to hear from you soon! 

Best regards, 
Claire