Hi, I'm currently using the Orielly infant head model (0.5 months) which is an anatomy template available in brainstorm to carry out EEG source localisation. When I add the generic Orielly EEG location and check the MRI registration all the electrode locations seem to be shifted to the left - can be seen especially with Fz, Cz and CPz being shifted from the midline.
Any ideas if this is intentional? or how to fix this?
Thank you
Avigayil
Indeed, we can observe this shift of the central line of electrodes towards the left for all electrode montages (10-20, 10-10, 10-05) and half of the age ranges (0.5m, 1m, 2m, 6m, 18m).
In practice, I don't think this would make much difference on the topographies or the source results, given the existing uncertainty of head shape and positioning of the electrodes. However, I agree that it would be better to start from electrode positions that look more centered.
@christianoreilly Do you observe the same shift on your end, and in MNE?
Or is this shift only due to the import in Brainstorm?
I validated that the automatic fit of the electrodes on the scalp surface produces this result. So maybe there is something wrong on this end, but the fit is almost perfect (max distance between electrode and scalp surface: 0.1mm), so it actually looks like it was designed like this.
I looked again at the import script you sent me with the data, and it uses a file that I don't have: fiducials.mat
import_template_to_brainstorm.zip (1.3 KB)
Could you please share this file with me?
Thanks
Hi,
Thank you for your response. I will continue to use the electrode configuration as it is.
Please can you clarify. If I'm using this head model as the default anatomy rather than individual subject anatomy do i need to compute the BEM surfaces or have they already been computed?
In addition, can I compute FEM surfaces from this head model?
Many thanks
If I'm using this head model as the default anatomy rather than individual subject anatomy do i need to compute the BEM surfaces or have they already been computed?
You should be able to use the BEM surfaces available in the templates: outer_skin, outer_skull, inner_skull.
In addition, can I compute FEM surfaces from this head model?
I don't know how the algorithms for computing FEM meshes work on these templates, I haven't tried it.
You can try the various solutions available: https://neuroimage.usc.edu/brainstorm/Tutorials/FemMesh
Thank you.
The head model is for 2 weeks old (0.5 months). Is it know what the PMA is for these infants?
The head model is for 2 weeks old (0.5 months). Is it know what the PMA is for these infants?
If this information is not present in the publication that presents these templates (https://www.biorxiv.org/content/10.1101/2020.06.20.162131v1.full), I don't know if we can obtain this information.
