[Eeglablist] removing eye blinks from 256 channel EEG

[Germano Gallicchio]

Dear Makoto,

provided that the more data points the better, is there any specific
formula for computing the minimum number of data points to pass to ICA?

Thanks,
Germano

On 4 December 2014 at 20:32, Makoto Miyakoshi <mmiyakoshi at ucsd.edu> wrote:

> Dear Jeff,
>
> > My epochs range from 3 to 20 minutes.
>
> Sounds too short for 256ch decomposition. You need at least > 1 million
> datapoints for it. Using high sampling rate such as 1000Hz increases
> apparent datapoints, but I'm not sure how it helps.
>
> > I generally find 1-3 ICs for each subject.
>
> This sounds too few for 256ch decomposition.
>
> > general background noise goes UP after these 1-3 components are removed.
>
> If the removed components are coupled with other components that cancels
> out each other, this could happen. However that's kind of rare and I don't
> see it very often... most likely your decomposition has problems.
>
> Makoto
>
> On Wed, Nov 26, 2014 at 3:18 PM, K Jeffrey Eriksen <eriksenj at ohsu.edu>
> wrote:
>
>>  EEGlabbers:
>>
>>  Does anyone out there have particular experience from removing eye
>> blinks from 256 channel EEG data using ICA? I have started to apply it to
>> 11 subjects with data recorded at 1,000 frame/sec, bandpass filtered &
>> downsampled to 250 fps. My epochs range from 3 to 20 minutes. I generally
>> find 1-3 ICs for each subject. When I remove these, there is still visible
>> remnants around the time of each eye blink. Of more concern is that the
>> general background noise goes UP after these 1-3 components are removed.
>>
>>  Any ideas that might improve my results? I can post some screenshots if
>> need be.
>> Thanks,
>>
>>  -Jeff
>>
>> _______________________________________________
>> 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
>>
>
>
>
> --
> Makoto Miyakoshi
> Swartz Center for Computational Neuroscience
> Institute for Neural Computation, University of California San Diego
>
> _______________________________________________
> 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/20141205/2163ed6f/attachment.html>