Wrong number of Vertices after mne.compute_source_morph

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1

Hi MNE community,

I tried to morph the source space of my participants to fsaverage in order to perfom permutation analysis next, however, the output of my morph.apply is incorrect.

I am using:

  • MNE version: 1.6.0
  • operating system: Windows 10

Here are my scripts:

# Load fsaverage Source Space
src_fsaverage_filename = dirFreeSurferData+'fsaverage/bem/fsaverage-vol-5-src.fif'
src_fsaverage = mne.read_source_spaces(src_fsaverage_filename)
# Define Vertices
src_fsaverage_vertices = [s["vertno"] for s in src_fsaverage]
# Here, I have a list of 14,629 vertices.

for sujMRI in range(nsujMRI):
    print(ListSujMRI[sujMRI])
    
    # Load sources
    src_vol_sujMRI_filename = dirSourcesData+ListSujMRI[sujMRI]+'/'+ListSujMRI[sujMRI]+'_dics_csd_rank_reg001.stc-vl.stc'
    src_vol_sujMRI = mne.read_source_estimate(src_vol_sujMRI_filename)
    
    # Load Forward Model
    fwd_filename = dirSourcesData+ListSujMRI[sujMRI]+'/'+ListSujMRI[sujMRI]+'_fwd.fif'
    fwd = mne.read_forward_solution(fwd_filename)
    src_sujMRI = fwd['src']
    
    # Compute source morph 
    morph = mne.compute_source_morph(
        src_sujMRI,
        subject_from=ListSujMRI[sujMRI],
        subjects_dir=dirFreeSurferData,
        subject_to='fsaverage',
        spacing=src_fsaverage_vertices
        )
    
    # Apply morph to sources
    src_vol_sujMRI_morph = morph.apply(src_vol_sujMRI)

  # The number of vertices in the source estimate after morphing is different 
# from the number of vertices in fsaverage (e.g., 22,782 for sujMRI=0).

I did not understand what happened, I did not have any error message.
I looked to the similar topics in the MNE support but none of them was useful for my problem.

I hope you will be able to help me.
Many thanks,
Camille.