(Optional) Where to write the separated files (override their default file names). This is a named list where each entry's name is a file type label, and each entry's value is a file name indicating where to write the corresponding separated file. The recognized file type labels are: "cortexL", "cortexR", "ROIcortexL", "ROIcortexR", "subcortVol", and "subcortLabs".
Entry values can be
NULL, in which case a default file name will be used: see
cifti_component_suffix. Default file names will also be used for files that need to be separated/written but without a corresponding entry in
sep_fnameswill be ignored if they are not needed based on
[ROI_]brainstructures. For example, if
sep_fnames$cortexRwill be ignored if specified.
write_dirargument can be used to place each separated file in the same directory.