Dear colleagues!
In our lab, new electrode caps were used together with the old ones in one project. However, in the new caps the electrode order partly differs. Now the question is whether I can average the participants with different data organization: the electrodes are the same, but their order in the EEG files is partly different.
How does the average function in Brainstorm work? Does it take into account names of the electrodes from the channel file for each participant or it takes matrixes of the same size with the order from the first file? Will it be possible to run the cluster-based permutation test?
Can I change the order of electrodes in the EEG file?
Best regards,
Anna
Hi Anna,
In the process Average > Average files, there is the checkbox "Match signals between files using their names". Be sure this is check to address the potential difference in number of channels and different order across across subjects (and even runs).
Best,
Raymundo
Hi Raymundo,
I will try this. Thank you very much for your help!
Best,
Anna
The menu " Match signals between files using their names" is only available when processing time-frequency, scouts or connectivity files.
In order to get a homogeneous list of channels for all your subjects, and be able to compute grand averages, you can use the process "Uniform list of channels". Select all the imported trials of all the subjects and run the process.
This would only work for the imported trials, not for the continuous files. All the forward and inverse models must be deleted and recomputed after running this process.
This alters deeply the database structure, with high risks of unrecoverable errors if something wrong happens. Make sure you make a full backup of your database before trying this.
https://neuroimage.usc.edu/brainstorm/Tutorials/Epileptogenicity#Uniform_list_of_channels