Regarding Reference channel

[Raymundo.Cassani]

Hello @Vridhi,

Yes, applying montages on raw data (to generate a new raw file) is a recent addition, April 2025

Applying on the raw data or imported is equivalent. The advantage of applying on the raw data is that the new file is saved as a raw file in Brainstorm binary file (.bst) which allows random access, so reading it and processing it can be done in blocks. Unlike imported data that must be processed all at once.

Also, in October 2025, we added a the Add-reference-channel-back montage in the GUI, which automatically creates the montage to add a channel, so no need to create a custom montage for this action:

Retrieval of reference channel

Hello Guiomar, we just implemented an automatic way to generate the required montage to recover the reference channel. [image] After that, you still need to apply the montage, to create a copy of the EEG data with the reference channel added. As expected in this new copy, the reference channel is flat in 0 V, but if we use average reference we retrieve its time series. Before computing the head model and estimate sources, the location of the new reference channel needs to be added.