[Eeglablist] re-epoching, ICA selected periods

[Makoto Miyakoshi]

Dear Jose,

1) Can I do ICA in select periods of time within my epochs?

Yes.

2) If not, I could try to re-epoch my dataset, perform ICA in the
re-epoched (shorter) dataset, and then re-inject the weight of the ICA back
to the original dataset), does that sound ok? I'm only interested in my
selected time period of interest, and the rest of the signal I would use it
because I need a buffer zone, and because long periods to compute power at
low frequencies,

Yes. But you want to feed ICA with sufficient number of data points, namely
ch^2 x 30.

3) Can I epoch relative to two triggers, i.e. for a sequence of triggers:
A, B, C, D, E I want to do from -0.5 relative to A until E,

Yes, you can use any subsample of data for ICA. This can increase its
sensitivity to event-related data, but loses data points to learn. That's
the trade off.

Makoto

On Fri, Mar 3, 2017 at 7:11 AM, José Luis <joseluisulloafulgeri at gmail.com>
wrote:

> hi,
>
> I'm analysing EEG data and want to perform ERP and time-frequency analyses,
> I'm doing the pre-processing with EEGlab,
> I wanted to move fast so I epoch my data and then I proceed with the
> artefact rejection. I epoch my data taken into consideration that for
> time-frequency I need a buffer zone,
> Now, I want to perform ICA but only in a selected time period of interest.
> I have several question here:
> 1) Can I do ICA in select periods of time within my epochs?
> 2) If not, I could try to re-epoch my dataset, perform ICA in the
> re-epoched (shorter) dataset, and then re-inject the weight of the ICA back
> to the original dataset), does that sound ok? I'm only interested in my
> selected time period of interest, and the rest of the signal I would use it
> because I need a buffer zone, and because long periods to compute power at
> low frequencies,
> 3) Can I epoch relative to two triggers, i.e. for a sequence of triggers:
> A, B, C, D, E I want to do from -0.5 relative to A until E,
>
> Thanks in advance for your help,
> Jose
>
> --
> José Luis ULLOA FULGERI, PhD
> +32477429007 <+32%20477%2042%2090%2007>
> +32492646477
> https://sites.google.com/site/joseluisulloafulgeri/
>
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-- 
Makoto Miyakoshi
Swartz Center for Computational Neuroscience
Institute for Neural Computation, University of California San Diego
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