[FieldTrip] ICA: eeglab and fieldtrip
"Jörn M. Horschig"
jm.horschig at donders.ru.nl
Tue Apr 1 08:24:11 CEST 2014
HI Aaron,
in addition to what Stephen and especially Stephen said (fun quiz: who
is who? ;)), pay attention that the colourscale might be different (also
for different subplots) and therefore the plots from different toolboxes
could suggest different activity in components, although in fact they
are similar.
Best,
Jörn
On 3/31/2014 10:10 PM, Stephen Whitmarsh wrote:
> Hi Aaron (i see Stephen just wrote a similar response)
>
> Those component topoplots look pretty good to me. In the FT one, I
> would say the first and third have a good change of being related to
> eyeblinks, and the fifth and twenty-fifth to eye-movements.
> However, you should really look at the timecourses to identify them as
> related to saccades and blinks, and by comparing them with your EOG
> recording.
>
> Although each ICA will *always* give you different results (if you
> don't specifiy the random seed), to make them more comparable you
> could add the EOG channel to the layout.
>
> Cheer,
> Stephen
>
>
> On 31 March 2014 22:08, Stephen Politzer-Ahles <spa268 at nyu.edu
> <mailto:spa268 at nyu.edu>> wrote:
>
> Hello Aaron,
>
> This doesn't, answer the rest of your questions, but... In your
> attached Fieldtrip image, component 1 does look like a likely
> blink component to me?
>
>
>
> Stephen Politzer-Ahles
> New York University, Abu Dhabi
> Neuroscience of Language Lab
> http://www.nyu.edu/projects/politzer-ahles/
>
>
> On Mon, Mar 31, 2014 at 11:52 PM, <fieldtrip-request at science.ru.nl
> <mailto:fieldtrip-request at science.ru.nl>> wrote:
>
>
> Message: 2
> Date: Mon, 31 Mar 2014 14:51:51 -0500
> From: Aaron Hanford <aharown at hotmail.com
> <mailto:aharown at hotmail.com>>
> To: "fieldtrip at science.ru.nl <mailto:fieldtrip at science.ru.nl>"
> <fieldtrip at science.ru.nl <mailto:fieldtrip at science.ru.nl>>
> Subject: [FieldTrip] ICA: eeglab and fieldtrip
> Message-ID: <BLU184-W8ABD13D8D59439530A857A3630 at phx.gbl>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Hi,I'm resending this with the figures turned into jpgs so
> it's not oversize...anyway, so I'm somewhat new to both
> fieldtrip and eeglab (although much more so to fieldtrip).
> I'm trying to figure out the following:
>
> On the exact same dataset, I did the following two things:
> 1) in eeglab, I just chose Tools -> Run ICA with default settings.
> Then, starting over with the original raw data:
> 2) In fieldtrip I ran the following: data =
> eeglab2fieldtrip(EEG,'preprocessing','none');cfg =
> [];cfg.method =
> 'runica';[comp]=ft_componentanalysis(cfg,data);layout =
> 'C:\Users\aharown\Desktop\fieldtrip-20140126\template\layout\easycapM17.mat';cfg.component
> = [1:31];cfg.layout = layout;ft_topoplotIC(cfg,comp);
> In both cases I then plotted the 2-D component maps, attached.
> So my question is, why are these results so completely
> different? The fieldtrip results don't look right at all, in
> that for instance they don't obviously identify a blink
> component (note that in this dataset, there is only one
> electrode placed near the right eye, not the left). I did
> this a handful of times and got the same sort of big
> differences. Am I doing something wrong or what?
>
> I actually think the cap file seems incorrect, but I've been
> assured by my PI that it's correct, so .... is there another
> likely answer?
> Thanks,
> Aaron
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--
Jörn M. Horschig
PhD Student
Donders Institute for Brain, Cognition and Behaviour
Centre for Cognitive Neuroimaging
Radboud University Nijmegen
Neuronal Oscillations Group
FieldTrip Development Team
P.O. Box 9101
NL-6500 HB Nijmegen
The Netherlands
Contact:
E-Mail: jm.horschig at donders.ru.nl
Tel: +31-(0)24-36-68493
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