[FieldTrip] Using ICA to filter data

[Rodolphe Nenert]

To summarize, the ICA will decompose your signal into as many components as
Electrodes.
Therefore, trying to decompose only one source is useless.
Did you use a full net of electrodes into your MRI machine or only EOG
electrodes?

Hope this helps,

Rodolphe N.

On Thu, Jun 16, 2011 at 11:42 AM, frank at greenant.net <fieldtrip at greenant.net
> wrote:

> I am trying to use fieldtrip to filter EOG data obtained in an MRI.
> I want to be able to spot the saccades in the samples and ideally measure
> their onset at the
> end of each trial.
>
> As you may guess, it's quite noisy and it's broad spectrum noise, despite
> pre-filtering.
>
> Ideally, I would like to isolate the component that corresponds to the MRI
> interference
> and then filter this out.
>
> I have managed to import the data and can run ft_componentanalysis
> but it fails with:
>
> runica() - data size (1,30720) too small
>
> My data is single channel, 40 epochs, each of 6 seconds (time locked to
> stim onset but not saccade onset)
> Is there a different method I should be using?
>
> I have posted some sample data and the current script (which reads in the
> data and runs preprocessing) to the following urls:
>
> http://greenant.net/temp/1_2_MRI_2011-04-29%2016:19:33.mat
> http://greenant.net/temp/EOG_analysis.m
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