[Eeglablist] when to re-reference

Stephen Politzer-Ahles spa268 at nyu.edu
Mon Dec 1 17:51:34 PST 2014

Hello Bin,

If you have bad channels that need to be interpolated, this must be done
before average referencing (see previous messages on the list about this
I also suspect that referencing may need to be done before artifact
rejection, depending on how you do artifact rejection, because some of the
methods will be affected by your choice of reference. For example, if you
reject based on extreme values (and apply this to all channels), you can
imagine a situation where a given channel might not exceed the value if the
reference is e.g. Cz but might change to exceed the value once the
reference is changed to e.g. mastoids. Ultimately, whether or not this is
an issue will depend on how you plan on doing artifact rejections, and
properties of your system (e.g., whether you have bipolar EOGs that use
their own reference separate from the rest of the electrodes).

There may also be other issues that I haven't thought of here, others on
the list may be able to clarify more.


Stephen Politzer-Ahles
New York University, Abu Dhabi
Neuroscience of Language Lab

On Sun, Nov 30, 2014 at 6:48 PM, Bin Wang <binwang87828 at gmail.com> wrote:

> Dear all,
> One simple question: I would like to try several different reference
> selections (i.e. average or mastoid), hopefully, I can find a relatively
> better one. My question is if the re-reference step must be done before
> epoch the data and artefact removal. Because I want to do all of
> preprocessing steps and artefact removal, and then apply several different
> re-reference selections, by this way I don’t need to do all of
> preprocessing steps again. Does it sound fine? Is there any other artefacts
> or problems that will be induced by the re-reference of last step.
> I am looking forward your any advices
> Thank you in advance,
> Bin
> ++++++++++++++++++++++++++++++
> Bin Wang
> Cognitive Neuroscience
> Institute of Neuroscience and Medicine (INM-3)
> Forschungszentrum Juelich,
> Leo-Brandt-Str. 5
> 52425 Juelich
> Email: b.wang at fz-juelich.de
> <https://webmail.fz-juelich.de/owa/redir.aspx?C=hswxAlx8wU6cP189jFS_1w0PFSKb8dAIIkV6dqtR-VUUMNMIisKisV7RZADeuZK3wPR2w27Q5yU.&URL=mailto%3abinwang87828%40gmail.com>
>      &  binwang87828 at gmail.com
> <https://webmail.fz-juelich.de/owa/redir.aspx?C=hswxAlx8wU6cP189jFS_1w0PFSKb8dAIIkV6dqtR-VUUMNMIisKisV7RZADeuZK3wPR2w27Q5yU.&URL=mailto%3abinwang87828%40gmail.com>
> <https://webmail.fz-juelich.de/owa/redir.aspx?C=hswxAlx8wU6cP189jFS_1w0PFSKb8dAIIkV6dqtR-VUUMNMIisKisV7RZADeuZK3wPR2w27Q5yU.&URL=mailto%3abinwang87828%40gmail.com>
> Telefon: 02461-61-9542
> ++++++++++++++++++++++++++++++
> _______________________________________________
> Eeglablist page: http://sccn.ucsd.edu/eeglab/eeglabmail.html
> To unsubscribe, send an empty email to
> eeglablist-unsubscribe at sccn.ucsd.edu
> For digest mode, send an email with the subject "set digest mime" to
> eeglablist-request at sccn.ucsd.edu
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://sccn.ucsd.edu/pipermail/eeglablist/attachments/20141201/e23d3f6a/attachment.html>

More information about the eeglablist mailing list