[Eeglablist] baseline removal when running 2 ICAs and frequency of interest finding

[Tarik S Bel-Bahar]

Hi Ida,

Your steps 1 to 4 seem fine, as long as you are feeding cleaned data to the
"ICA 1stTime" step.
After step 4, then you can follow basic steps to get ERP, single-trial,
frequency, and dipole info on the extra-clean data,
as described in the eeglab tutorial, and the many articles that use eeglab
and ICA for their analysis (you can find all of these on Google Scholar).
Note that there are many choices on how to drop bad epochs when doing your
step 4.

If you have not done the eeglab tutorial, it is recommended that you do it,
rather than using your fresh data to figure things out.
Once you figure out all basic functions and steps with sample data, then I
suggest pushing your data through some well-decided steps.

Regarding the "baseline removal" based on the Groppe article, you should
look more closely at those articles to determine exactly
what you are doing and why you are doing it. you may also want to contact
the author directly so you have good clarity.

Good luck with your process and looking forward to hearing of your success.

Best wishes,
Tarik


On Sun, Mar 3, 2013 at 5:29 AM, ida miokovic <ida.miokovic at gmail.com> wrote:

> Dear eeglablist,
>
> After reading through many q&a here on eeglab list, I found the
> recommended literature of Groppe et al regarding baseline removal and went
> through it.
>
> My initial plan was to run ICA on the epoched data 1st time, then to
> remove bad trials (not the bad components) and then to run ICA second time
> after which I will hopefully obtain better decomposition. Going through
> q&a, it wasn't clear to me what is the procedure when ICA is applied 2
> times. This is short description of the steps as I understand them at the
> moment:
> 1. data epoching (without any baseline removal)
> 2. ICA 1st time
> 3. bad trials removal
> 4. ICA 2nd time
> 5. baseline correction on the whole epochs(?)
>
> And also one more question, if I am interested into finding a certain
> frequency presence in channels and ICs, is Tools --> Component spectra and
> maps good option? In the field of "Freq.to analyze" I would put the one of
> my interest and obtain the components (for example 5 of them) and the
> channel with the highest power of frequency of my interest. I have to learn
> more about dipfit, since I think I will actually need the source of the
> signal of the certain frequency localization...
>
> Thank you very much in advance,
>
> Regards,
>
> Ida
>
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