Yes, the filesep there is reduntant, but this won’t affect the result of dir.
As I said, the groupconnectome data should be unzipped into lead/connectomes/dMRI/ now. You will then see some folders with the name like “Groupconnectome (Horn 2013) full” there. The data.mat files are in these folders. If you have all the group connectome data ready, you will see them in the “Prepare DBS stats” section under “which connectivity metric to use” (seems the popupmenu is not large enough to show the full names of the folders), from where you can also choose the patient specific fiber tracts.