[Freesurfer] High resolution fMRI and resolution of anatomical scans

Hi, We are planning to collect high resolution *functional* MRI for a group of subjects with voxel size smaller than 1 mm. For these subjects, we already have reconstructed *anatomical *scans with 1 mm voxel size. The question is, do we need to re-collect *anatomical* scans for these subjects with smaller voxel size (e.g. 0.5 x 0.5 x 0.5) or we can still use the old anatomical data for co-registration with freesurfer.

P.S.: We usually analyze our subjects in native space but technically we can do this in fsaverage space. So, we only need this co-registration for pre-processing and mapping fMRI data to fsaverage space.

Regards