Hello, and thank you very much for the valuable tutorials you’ve shared — they’re really helpful and insightful.
I just had a quick question: what is the rationale behind the numerical values shown in the figure?
Is there any specific rule or theoretical basis for determining these numbers?
Which figure are you specifically curious about?
This is disused in the BEM tutorial:
https://neuroimage.usc.edu/brainstorm/Tutorials/TutBem#Number_of_vertices_per_layer
The default values are high (1922 vertices per layer), to ensure that by default the results are good. If you can afford it computationally, you should use these 1922 vertices per layer. If you have to decrease these values, you can try for instance with 1082 vertices (scalp) and 642 vertices (outer skull and inner skull).
If these BEM surfaces will be used with OpenMEEG, "The recommended mesh size is approximately 600 to 800 points per surface." This is mentioned in the OpenMEEG documentation, as well in OpenMEEG publications:
Thank you.