[Eeglablist] Questions about ICA component rejection in EEGLAB

[Liu Pan]

Hi Arno,

Thanks, maybe my understanding was wrong. One more quick question: Getting
back to *Tools>Reject data using ICA>Reject components by map*, are
there any off-GUI functions for the greyed out buttons? Also, for the
fuction *POP_REJCOMP *mentioned in *HELP*,  where could I find more details
about it?

Thank you very much, Pan

On Tue, Feb 26, 2013 at 12:13 AM, Arnaud Delorme <arno at ucsd.edu> wrote:

> Hi Pete,
>
> the functions mentioned in the paper are to reject data epochs.
> There are functions to reject ICA components automatically when you are
> using STUDY (group analysis). I am thinking of the CORRMAP plugin
> and EyeCatch implemented by Nima Bigdely <nima at sccn.ucsd.edu> (email
> him as I do not think his plugin is available on the internet). It will be
> able to detect your blink components in each subject.
>
> I think the ADJUST plugin might also do this kind of things but I am not
> sure.
>
> Arno
>
> On 25 Feb 2013, at 21:05, Liu Pan wrote:
>
> Hi Arno,
>
> Thanks for your reply! But the function mentioned in your paper is to
> reject ICA components (not epochs); whereas the function "*Tools > Reject
> data using ICA > Reject data (all methods)" *is to reject epochs/trials
> based on ICA activities, not components, right? Or did I miss anything on
> this function?
>
> Thanks for your clarification! Pan
>
>
>
> On Mon, Feb 25, 2013 at 11:51 PM, Arnaud Delorme <arno at ucsd.edu> wrote:
>
>> Dear Liu,
>>
>> (1) yes, the menus are greyed out but to tell the truth, they have always
>> been. This is not the function that is referred to in the paper you
>> mentionned. The function corresponds to the menu "Tools > Reject data
>> epochs > Reject data (all methods)" and "Tools > Reject data using ICA >
>> Reject data (all methods)"
>>
>> Arno
>>
>> On 25 Feb 2013, at 18:32, Makoto Miyakoshi wrote:
>>
>> Dear Liu,
>>
>> (1) I've never noticed them until I confirmed it now. You are right, they
>> are grayed out. They are not available from GUI at least, and I don't know
>> if there are off-GUI functions for them.
>>
>> (2) Plot - Component ERPs runs pop_envtopo() where you can evaluate
>> percent variance accounted for (pvaf) and related measures that tell you
>> each IC's contribution to scalp ERPs. ICs with lower numbers have high
>> variance since they are sorted so after ICA. For example your IC90-IC100
>> would not have even 1/10 of variance of IC1 (could be even 1/100 which is
>> 40dB smaller in FFT plot). This means that discarding 50 out of 100 ICs
>> does not mean discarding 50% of data (variance). If you want to measure how
>> much 'data' are rejected, you may check pvaf as one of measures.
>>
>> Makoto
>>
>> 2013/2/25 Liu Pan <pliu261 at gmail.com>
>>
>>> Dear eeglabbers,
>>>
>>> I have 2 questions about the ICA component rejection function of EEGLAB:
>>>
>>> (1). I read the paper "Automatic artifact rejection for EEG data using
>>> high-order statistics and independent component analysis" by Drs. Delorme,
>>> Makeig, and Sejnowski.
>>> http://www.google.ca/url?sa=t&rct=j&q=&esrc=s&frm=1&source=web&cd=2&ved=0CEAQFjAB&url=http%3A%2F%2Finc.ucsd.edu%2Fica2001%2F117-delorme.pdf&ei=JakrUbjhCMe30gHevIGoCQ&usg=AFQjCNGwjRtjnTiRvUxguqJNAejvoD6a7g&sig2=9BQuz03YEzUOszEreafYgA
>>> In *section3.3 *the authors mentioned that in addition to manually and
>>> visually rejecting ICA components based on the component properties, there
>>> is a function in EEGLAB software by which one can set an adequate rejction
>>> threshold for three high-order statistical measures (the entropy of the
>>> activity of the component, the kurtosis of the activity, and the kurtosis
>>> of the components' spatial map), then one can automatically detect and
>>> reject components (insteady of mannually doing so). In search of this
>>> function in EEGLAB, I found that in the *Tools--Reject data using
>>> ICA--Reject components by map* function, there are 3 buttons at the
>>> bottom of the popped out window (*set threshods, see comp. st..., see
>>> projection)* which appear to be grey and inactive. I suppose these
>>> buttons, especially the on *set threshods, *are relevant to the
>>> automatic ICA component rejection function mentioned in that paper.
>>>  However, these buttons are not active and cannot be used. According to the
>>> *Help* file of this function, *"if the function POP_REJCOMP is ran
>>> prior to this function, some fields of the EEG datasets will be present and
>>> the current function will have some more button active to tune up the
>>> automatic rejection."*  I searched *POP_REJCOMP* function but failed
>>> to get a clue from the tutorial nor the previous discussion list. Could
>>> anyone give me any suggestion about this? Are these inactive buttons the
>>> ones for automatic ICA component rejection?  If yes, how can I get them to
>>> work?
>>>
>>> (2). While doing ICA component rejection, how many of the original
>>> components would you reject? I sometimes rejected almost half of them, is
>>> it too much or not?
>>>
>>> Thank you very much for any of your input in advance! Pan
>>>
>>> --
>>> Liu Pan, PhD. Candidate
>>> Neuropragmatics and Emotion Lab (Pell Lab)
>>> School of Communication Sciences and Disorders
>>> Faculty of Medicine, McGill University
>>> Montreal, Canada
>>>
>>>
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>>
>>
>>
>> --
>> Makoto Miyakoshi
>> JSPS Postdoctral Fellow for Research Abroad
>> Swartz Center for Computational Neuroscience
>> Institute for Neural Computation, University of California San Diego
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>>
>
>
> --
> Liu Pan, PhD. Candidate
> Neuropragmatics and Emotion Lab (Pell Lab)
> School of Communication Sciences and Disorders
> Faculty of Medicine, McGill University
> Montreal, Canada
>
>
>


-- 
Liu Pan, PhD. Candidate
Neuropragmatics and Emotion Lab (Pell Lab)
School of Communication Sciences and Disorders
Faculty of Medicine, McGill University
Montreal, Canada
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