HCP flattened GIFTIs from fmriprep?


I am a struggling 3rd year student trying to research dementia in rsfMRI images.

I am using BrainVortexToolbox and it takes flatten left and right hemisphere data.
Currently I am only focusing on the left hemisphere and have the following files per subject from the HCP dataset (which is made up of healthy subjects)
Positional (I assume anatomical) - L.flat.32k_fs_LR.surf.gii
Resting State - rfMRI_REST1_LR_Atlas.dtseries.nii

I have selected dementia subjects from the ADNI dataset and preprocessed with fmriprep with the ‘–cifti-outputs’ option but the output doesn’t appear to have what I need.

I looked into freesurfer and found it can flatten the surface afterwards using FreeSurferOccipitalFlattenedPatch, however I believe that will only work for the anatomical scans.

Is anyone able to help me with converting the ADNI data to give me the same output that the HCP dataset gives me please.

Thank you, Scott