mne.create_default_subject(fs_home=None, update=False, subjects_dir=None, verbose=None)[source]

Create an average brain subject for subjects without structural MRI.

Create a copy of fsaverage from the Freesurfer directory in subjects_dir and add auxiliary files from the mne package.

fs_homeNone | str

The freesurfer home directory (only needed if FREESURFER_HOME is not specified as environment variable).


In cases where a copy of the fsaverage brain already exists in the subjects_dir, this option allows to only copy files that don’t already exist in the fsaverage directory.

subjects_dirNone | str

Override the SUBJECTS_DIR environment variable (os.environ[‘SUBJECTS_DIR’]) as destination for the new subject.

verbosebool | str | int | None

If not None, override default verbose level (see mne.verbose() and Logging documentation for more). If used, it should be passed as a keyword-argument only.


When no structural MRI is available for a subject, an average brain can be substituted. Freesurfer comes with such an average brain model, and MNE comes with some auxiliary files which make coregistration easier. create_default_subject() copies the relevant files from Freesurfer into the current subjects_dir, and also adds the auxiliary files provided by MNE.