I have digitized my electrode locations using brainsight TMS software and saved the file as .sfp file. Is the best approach to import the EEG with standard cap locations and then add the electrode positions separately? (i.e. Add EEG positions -> From File) If I do this, will it match the digitized positions from the .sfp file to the EEG electrodes based on the channel labels? Or does the list of channel labels and positions in the .sfp file need to be in the same order as the channels in the EEG files? Also, this seems to display two sets of EEG points when I select MRI registration -> check (see figure attached).
Would it be better to import the digitized electrodes into the eeg file (eeglab) prior to importing to brainstorm?
Thanks for any help!
EEG_3D_Subject06.tif (438.7 KB)
Yes, using the menu "Add EEG positions > Import from file" matches the channels by label, the order doesn't matter. See the EEG tutorial for additional details:
https://neuroimage.usc.edu/brainstorm/Tutorials/Epilepsy#Prepare_the_channel_file
Also, this seems to display two sets of EEG points when I select MRI registration -> check (see figure attached).
The green points are the head points originally imported.
(the electrodes positions are copied into the list of "head points", used for automatic registration, warping, etc)
I'm not sure why the electrodes (white points) were moved but the head points (green points) were not moved accordingly. Have you done some manual transformations of the electrodes positions, that are not rotations or translations?
If you want to get rid of these confusing green points: right-click on the channel file > Digitized head points > Remove all points.
Would it be better to import the digitized electrodes into the eeg file (eeglab) prior to importing to brainstorm?
I don't think it matters.
(but I'm not 100% sure of all the consequences the two approaches have)