[Eeglablist] What kind of artifact

Tarik S Bel-Bahar tarikbelbahar at gmail.com
Wed Dec 30 11:28:10 PST 2015

Hello Mina, a few notes below that should help you. Happy new year!

Those components you snet look mixed (containing some combination of neural
and artifact information). I woul dnot throw them out unless they had
something heavily artifactual about them. Just from what you sent it's not
evident that you should "remove" these ICs.

Run SASICA, ICMARC, and MARA if you have not to get some determination if
those ICs are too spatially focal, just happen in a few trials, mixed or
neural, etc..

You would also benefit, if you have not yet, from reading the ICMARC
article from Frolich, and the chapter from Onton and Makeig in the Luck
Handbook of Event-Related Potential Components

See also discussions in eeglablist, the tutorial information on ICA and ICA
rejection, and several articles you can find on Google Scholar (or
mentioned on the eeglablist) that are related to your topic.

You can also take a look at the channel data that created those ICs, and
see if there is something wrong with those channels visually.

If you haven't look more closely at the properties of the ICs using the
Plot Component Properties option from the eeglab gui to take a closer look
at the spectra between 2 and ~30 hz, and to look at whether those ICs are
"active" across most of the trials used for the ICA (you can see the trials
in the Component Properties view too).

Last, most ICA decompositions give many ICs that are pretty much focused on
one channel. These are usually ICs that do not explain a lot of variance.

For ICA rejection, there are some groups that only remove ICs that very
clearly eye-artifacts or muscle-artifacts, whereas others remove a lot more
ICs. Other researchers just focus on the neural ICs that are interpretable,
and examine the dynamics of those clean interpretable ICs.

On Mon, Dec 28, 2015 at 1:32 PM, Mina Marmpena <mina.marmpena at gmail.com>

> Dear EEGLAB list,
> Could you please advise me for the below components? I get it a lot in all
> my subjects and I wonder what kind of artifact could that be.
> [image: Inline image 1]
> Thank you,
> Mina
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