Bug? ieeg.project_sensors_onto_brain

Hello everyone!

To deal with “brain shift” due to changes in pressure during the craniotomy, I am trying to project the ECoG electrodes onto the brain surface as described in mne.preprocessing.ieeg.project_sensors_onto_brain — MNE 1.3.1 documentation.

I was able to project the electrodes onto the lateral surface of the cerebrum, but could not project those onto the occipital and basal temporal cortices. It seems that they are projected onto the surface of the cerebellum.

I tried changing a value of the parameter “n_neighbors”, but it didn’t work.
How can I project the electrodes onto the surface of the cerebrum instead of the cerebellum?

Thank you!

  • MNE version: 1.3.1
  • operating system: e.g. macOS 13 Ventura
# Create BEM
from mne.bem import make_watershed_bem
make_watershed_bem(subject=SUBJECT)

# project sensors to the brain surface
brain_kwargs = dict(cortex='low_contrast', alpha=0.2, background='white')
raw.info = mne.preprocessing.ieeg.project_sensors_onto_brain(
    raw.info, subj_trans, SUBJECT, n_neighbors=10)

# plot projected sensors
brain = mne.viz.Brain(subject=SUBJECT,
                      title='After Projection', **brain_kwargs)
brain.add_sensors(raw.info, trans=subj_trans)
brain.show_view(**view_kwargs)