[Eeglablist] effect of deleting ICs parts in time domain

[Makoto Miyakoshi]

Dear Ida,

> after performing ICA decomposition I realized that first 30 seconds of
all calculated ICs are probably artifacts

That means the first 30 sec of your data contains serious noise. It's also
likely that your have ICA is affected by the noise. You may want to run ICA
again without the first 30 sec of your data. After you run ICA, you can
copy the weight matrix etc. to the other datasets (check 'Edit' - 'Dataset
info' and see the bottom of the GUI).

Makoto

2013/7/13 ida miokovic <ida.miokovic at gmail.com>

> Dear List,
>
> after performing ICA decomposition I realized that first 30 seconds of all
> calculated ICs are probably artifacts (I did not perform manual rejection
> of bad eeg data portions since I am not a medical student and I was afraid
> to remove useful part of the data) because there are periodic shapes
> appearing in all components time domain that look like movements now.
>
> Then I looked into eeg data and realize that same happens with that data
> set.
>
> I am now wondering if I manually delete certain part of all calculated
> independent components (by selecting for example time period 0 - 30 secs
> and press REJECT button) from their time domain - are those brain
> activations going to be deleted from the eeg dataset and are those first 30
> seconds of ICs related with first 30 seconds of eeg data?
>
> I tried to explain it clearly and I hope you can understand my doubts.
> What also might be important for you to know that my data is not epoched
> for certain reasons related with tasks nature.
>
> If that is what happens, is there a way to remove part of ICs (all of
> them) or EEG data by code and not by eeglab form?
>
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-- 
Makoto Miyakoshi
Swartz Center for Computational Neuroscience
Institute for Neural Computation, University of California San Diego
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