[FieldTrip] Using ICA to filter data

[frank@greenant.net]

It's a bit of a unique experiment, we're trying to use an ECG machine
to acquire EOG, so it's only a single output channel.

i guess what I need is a temporal ICA rather than a spatial one...

On 17/06/2011, at 2:48 AM, Rodolphe Nenert wrote:

> 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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