[Eeglablist] Re-referencing to average and retaining (Brain Vision)

[Marcin Naranowicz]

Dear All,

I have encountered a problem with re-referencing that I cannot solve after reding respective threads on the EEG list and consulting the EEGLAB tutorials.

I am currently analysing EEG data collected with the Brain Vision software (64 channels + two EOGs, the ActiCHamp amplifier, online reference electrode: Fz) in EEGLAB and MATLAB through scripting. I am trying to re-reference the data to the average reference, retaining the online reference channel (Fz).

I followed the instructions provided in the tutorial: imported a raw data file (.vhdr) and appended the missing Fz channel as well as set it as a reference in the Channel location editor. The main EEGLAB window now provides the following information : - Channels per frame: 65 (same as after importing the data), - Reference: Fz, - Channel locations: yes. Yet, when trying to re-reference the data to the average reference and select the reference electrode to be retained (the 'Add old reference channel back to the data' function), I receive the following warning message: "There are no reference channel defined, add it using the channel location editor." When I type 'Fz' manually, Matlab ignores it anyway ("Error with old reference: ignoring it").

Do you possibly have an idea what I can do about this? I would much appreciate your help. Script-based solutions are also more than welcome.

Kind regards,
Marcin Naranowicz