Cross-hemisphere comparison#

# Author: Christian Brodbeck <christianbrodbeck@nyu.edu>
#
# License: BSD-3-Clause

import mne

data_dir = mne.datasets.sample.data_path()
subjects_dir = data_dir / 'subjects'
stc_path = data_dir / 'MEG' / 'sample' / 'sample_audvis-meg-eeg'
stc = mne.read_source_estimate(stc_path, 'sample')

# First, morph the data to fsaverage_sym, for which we have left_right
# registrations:
stc = mne.compute_source_morph(stc, 'sample', 'fsaverage_sym', smooth=5,
                               warn=False,
                               subjects_dir=subjects_dir).apply(stc)

# Compute a morph-matrix mapping the right to the left hemisphere,
# and vice-versa.
morph = mne.compute_source_morph(stc, 'fsaverage_sym', 'fsaverage_sym',
                                 spacing=stc.vertices, warn=False,
                                 subjects_dir=subjects_dir, xhemi=True,
                                 verbose='error')  # creating morph map
stc_xhemi = morph.apply(stc)

# Now we can subtract them and plot the result:
diff = stc - stc_xhemi

diff.plot(hemi='lh', subjects_dir=subjects_dir, initial_time=0.07,
          size=(800, 600))