Eliminate EEG channels from the analisys with ESI

Discussions
1

Good morning,
I’d like to ask some information regarding the elaboration procedure of the EEG with the EEG source imaging.
To eliminate some EEG channels from the analysis, is it sufficient to set those channels on EEG_NO_LOC or in this way only the localization gets removed but the channels get still considered in analysis? In this latter case what would be the correct method to exclude them?
Thank you

2

Hi Alice,

Welcome to the brainstorm forum. That works indeed, you would have to calculate the forward model again in that case, though that removes that channel for all the source analysis, which is not something preferable if you have multiple recordings for the same subject. What you can also do is mark the channel as bad in the recording. Brainstorm will take that into account when calculating the sources. I would advise the second method since that is easier to do :slight_smile:

Kind regards,
Steven

3

If you want to organize your data correctly, I wouldn't say you have the choice of one method or the other:

  • If you have channels that are not recording EEG: set their type to something else than "EEG" (eg. "EXTRA" or "OTHER").
  • If you have isolated EEG channels for which you don't have 3D locations: set their type to "EEG_NO_LOC" or let the process "Add EEG positions" do it.
  • If you have EEG channels that record bad quality data or no data at all: mark these channels as bad. https://neuroimage.usc.edu/brainstorm/Tutorials/BadChannels