[Eeglablist] EEGLab trouble re-referencing my data to multiple electrodes

[Cedric Cannard]

Dear Maria,

Are you sure your reference labels are Fp1 and AF8? Because these are prefrontal electrodes, not earlobes. In any case, is there a rationale for using linked mastoid referencing for your data? Because if you have 64 electrodes, it is much better to re-reference to average or infinity/REST (both available in EEGLAB) than to linked mastoids, which is vulnerable to left/right dipole fluctuations.  

Cheers,

Cedric Cannard


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------- Original Message -------
On Thursday, May 18th, 2023 at 9:23 AM, Maria Coelho via eeglablist <eeglablist at sccn.ucsd.edu> wrote:


> Hi,
> 
> Firstly, thank you for the open discussion list on EEGLab matters. I am
> currently preprocessing my data and mailing lists like these are very
> useful.
> 
> I am having difficulties in re-referencing my data.
> 
> By default in Brain Vision Recorder, my reference channel is Fp1. When I
> import my .vhdr files to EEGLab interface, this channel doesn't appear in
> "Edit --> Channel Locations" (as I am assuming EEGlab also refers to Fp1 as
> 
> my reference channel).
> 
> However, I have two references, in both earlobes: Fp1 and AF8, and I need
> to reference my data to the mean of these two channels' data.
> 
> I have checked the procedure in EEGlab Tutorial, where I can create a new
> channel (in Edit --> Channel Locations) in case the original reference does
> 
> not appear visible, as it is the case, in Fp1 for instance. Yet, by
> creating Fp1 as a new channel and set it as my reference (as described in
> Tutorials --> Preprocess Data --> Re-referencing --> Retaining the
> 
> reference channel), the new channel Fp1 does not contain its original data.
> 
> With this issue, I cannot proceed to the next step, where it is described
> how to use two references as I wish to use (in Tutorials --> Preprocess
> 
> Data --> Re-referencing --> Re-referencing to multiple electrodes).
> 
> 
> I am using the brain products 64-channel EEG system.
> 
> Thank you in advance, and I hope I was clear in describing my problem.
> I look forward to hearing from you.
> 
> Maria Coelho
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