In this tutorial, we compare the head models computation using the methods available in brainstorm.

At this time, the FEM implementation is available for the EEG and the MEG computation. We will integrate and test soon the FEM for sEEG and ECOG.

EEG with a spherical head model

In this part we used the spherical head model distributed by the duneuro team (sphere). The following figure shows on the left the surface model and on right the tetrahedral mesh.

The model has three layers, the brain (inner skull), the outer skull and the scalp.

For the source space or dipole position, we will use a realistic cortex distributed with the ICBM default subject of brainstorm.

Regarding the electrode's positions, we use the same position defined in this file

the BEM, FEM forward computation in basic model (realistic head model 3 layer) and also within in a spherical head model with an analytical solution.

Describe femVSbem here.

Compare the performance of the mesh resolution vs the leadfield approximation

v10, v1, v0.1 and v0.01

v0.1 and V0.01 are almost the same ....

difference appears on v10

in spherical head model

same observation on the lf view

difference appears on the v1 and worse for v10

EEG forward within 3 layers head model :

In this example we compute the head model for the ICBM head model using the openmeeg method and then we generate the fem mesh for the same subject, then we compute the the leadfield using the Duneuro method v = 0.1 default value. MNorm

sloreta