Hello,
I have a question concerning channel files & format. We run our EEG studies using Netstation EGI (256 channels). We also have a Geodesic dome that we use for sensor registration (using Netlocal software) - manually marking sensor and fiducial locations. When exporting the channel file, we are given 3 options: .nsi, .sfp & .elp. Of the three, I am only able to load .sfp & .elp into Brainstorm (.nsi does not seem to be supported). When examining the contents of the other two formats (.elp & .sfp) in Brainstorm, the .elp file contains a total of 260 entries (256 EEG electrodes, CZ & 3 fiducial positions). On the other hand, the .sfp file contains only 257 positions (256 electrodes +CZ), the fiducial positions are either absent or not visible. Does it matter which format we use for coregistering the anatomical information with EEG sensors?
The file format itself does not matter. The fiducial positions can be useful, if they are the NAS/LPA/RPA fiducials we mark in the MRI Viewer when we import the anatomy.
If they are defined in the file, they will be used for aligning the electrodes on the MRI, as described in this tutorial: http://neuroimage.usc.edu/brainstorm/Tutorials/ChannelFile
The names accepted for the fiducials are the following (not case sensitive):
NAS: nas, nasion, nz, fidnas, fidnz
LPA: lpa, pal, og, left, fidt9, leftear
RPA: rpa, par, od, right, fidt10, rightear
This looks good, you have nothing to change.
The lines FidNz, FidT9 and FidT10 should be automatically interpreted as fiducial points (NAS/LPA/RPA) and aligned on the MRI.
