[Eeglablist] Low Pass Filtering and ERSP

[Makoto Miyakoshi]

Dear Gozde,

If you can upload screenshot of the data in question, I can help you
better. Let's identify what was wrong.

Generally speaking, it would be still ok to apply 20-Hz low pass filter if
you say only < 20 Hz of your data seems intact, just in the worse case.

Makoto

On Tue, Dec 13, 2016 at 11:21 PM, Gozde BAYER <gbayer at hacettepe.edu.tr>
wrote:

>
> Dear EEGLAB List,
>
> During my raw EEG data recording from different subjects, I observed
> (online from the FFT plot of related software) some kind of 'noise'
> standing still at around 20-25 Hz and I could not get rid of that for some
> reason. So I decided to let EEG stream under
> this condition. Therefore I applied low pass filtering to the raw data at
> 20 Hz, and analyzed offline the remaining frequencies with EEGLAB. I
> created STUDY design for the purpose of the experiment. But when I plot
> ERSP of a specific channel, I could still distinguish frequencies surviving
> above 25 Hz. I checked from the workspace of Matlab as well. What could be
> the reason of that? Since I am sometimes getting this 20 Hz peak during raw
> EEG data recoding (by the way, I am trying to find out why this is the
> case), it is important for me to really understand the phenomenon behind
> that..Indeed, those frequencies just above 20 Hz are also of great
> importance for my future analysis..If they are able to survive -somehow-
> then would it be reliable to analyze beta frequency band under this
> condition?
>
> I appreciate any help,
> Best wishes.
>
> Gözde BAYER
>
>
>
> _______________________________________________
> Eeglablist page: http://sccn.ucsd.edu/eeglab/eeglabmail.html
> To unsubscribe, send an empty email to eeglablist-unsubscribe at sccn.uc
> sd.edu
> For digest mode, send an email with the subject "set digest mime" to
> eeglablist-request at sccn.ucsd.edu




-- 
Makoto Miyakoshi
Swartz Center for Computational Neuroscience
Institute for Neural Computation, University of California San Diego
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://sccn.ucsd.edu/pipermail/eeglablist/attachments/20161229/0cfe4d13/attachment.html>