Hidding subcortical current

Discussions
1

Salut François,
I wonder if it is possible to display only the cortical sources and hide current computed at sub-cortical level?
Thanks

2

No, I don't think there is any easy way to do this.
You can try to play with the resection tools at the bottom of the Surface tab. If you don't obtain what you want, maybe recompute the sources with only the cortex.

3

Thanks for the reply. I am not sure that it corresponds to what you are suggesting, but I compute the head model using the cortex surface (not the MRI volume), but it does not prevent current to be displayed at non-cortical levels.

4

Are you talking about the flat part below the corpus callosum that closes the hemispheres in FreeSurfer surfaces?
When using a surface-based head model, Brainstorm evaluates the source activity at all the points of the surfaces selected for the subject. If the surface is closed, it includes many points that are not "cortical sources", indeed.

If you really want to get rid of them, you can create a scout and remove its vertices from the surface (menu Scout > Edit surface > Remove selected scout).
Or you can use a "Mixed head model", selecting only the cortex (http://neuroimage.usc.edu/brainstorm/Tutorials/DeepAtlas). This makes everything much more difficult to process after, so not really a recommended option.

If this is off-topic, please post a screen capture to illustrate your question.

1 Like
5

Many thanks, your suggestion works well. It also works if we create a scout of the area we want to hide, make the scout opaque, and then match the color of the scout with the color of the cortex surface.

6

The solutions I was offering were restricting the source space and then estimating the sources: the maps you obtain are valid min norm maps. It is a global inverse, if you add or remove a few dipoles to the source space, the min norm solution is modified everywhere.

This last approach you mention (masking parts of the results obtained after computation) is a bit similar to using Photoshop to hide the results you don't want to see, and it's a bit more complicated to justify methodologically :slight_smile: