Why cannot I select the "custom source model"?

[Jixiang]

Dear all, I'm following the tutorial "SEEG epileptogenicity maps" and the work of Matarrese in 2023. When I computed the head model, I found that "Custom source model" cannot be selected.

Then I would like to know how to limit the source space to one hemisphere with electrodes implanted?
" For each patient, we constructed a forward model with boundary element method using OpenMEEG.53 Source space included one or both hemispheres depending on the implanted electrodes’ locations (Fig. 1B)."
Reference
Matarrese MAG, Loppini A, Fabbri L, et al. Spike propagation mapping reveals effective connectivity and predicts surgical outcome in epilepsy. Brain . 2023;146(9):3898-3912. doi:10.1093/brain/awad118

[Raymundo.Cassani]

@Jixiang

When I computed the head model, I found that "Custom source model" cannot be selected.

Did you define the mix model before computing the head model?
Check the three first sections in this tutorial on mix models:
https://neuroimage.usc.edu/brainstorm/Tutorials/DeepAtlas

@Jixiang

Then I would like to know how to limit the source space to one hemisphere with electrodes implanted?

Using the same approach as with mix models, but instead of adding more regions, make a Source model that comprises one hemisphere.

[Jixiang]

Thank you so much！ Really helps a lot!