EEG Locations/ average

MATHIOT · May 9, 2025, 9:15am

Hello,
Sorry for my perhaps naive question. I'm new to EEG and Brainstorm.
I have a problem with the number of channels, which is 204 for all my participants, but Brainstorm detects either 205 or 206. I type "add EEG positions" and select my headset. Therefore, I can't average between my subjects because the matrix is different. I tried standardizing with "uniform list of channels," but it doesn't work. I get an error message related to the raw data, which can't be modified with this process. Could you help me? I want to average events between my subjects; this is currently impossible.

Thank you in advance for your help.

tmedani · May 9, 2025, 5:24pm

Hi @MATHIOT
There may be slight differences in data acquisition parameters between subjects or on the data file.

Please check the channel files on brainstorm to ensure the same set of channels is used for all subjects.

You can right-click on the channel file, select "Edit channel file", and verify whether any extra channels are marked as EEG.
If so, you can reassign them to MISC or mark them as Not EEG.

You can check this here: