[Eeglablist] ICA on continuous data - eye artifact component

[Makoto Miyakoshi]

Dear Ida,

I saw your plot. This is most likely EOG judging from the topo map, and
contains a few bad portions of the data judging from the ERPimage. Remove
these bad portions and your IC1 ERPimage should look better.

Makoto


2013/4/2 ida miokovic <ida.miokovic at gmail.com>

> Dear Makoto,
>
> Within IC1 I see horizontal line in the lower half of the figure, meaning
> this component "is happening" only during one trial (right?), which is
> strange to me since everything else about this component (location,
> activity power spectrum and plot of the component in time domain) is
> showing that it is most likely eye artifact...
>
> In mentioned diagram, I would expect it to be more distributed through
> trials and to look more like:
> http://sccn.ucsd.edu/wiki/File:I94component3_properties.jpg
>
> One data set of mine consists of one subject performing one task (for
> example for 15 secs) than there was a break time (10 secs which I manually
> removed from he data set) and than again task performance etc. What is
> considered in this case to be a trial? Here I have some continuous data
> with markers marking the moments when task is performed and some boundary
> markers when unuseful data (break time) was rejected.
>
> All the best
>
> Ida
>
>
> On Tue, Apr 2, 2013 at 3:27 AM, Makoto Miyakoshi <mmiyakoshi at ucsd.edu>wrote:
>
>> Dear Ida,
>>
>> >Third mentioned diagram is shown with dimensions: 200 trials and 810 ms
>> on y and x axis respectfully (image is in the attachment) - why exactly
>> these values are taken? Could I change those?
>>
>> These are chosen arbitrarily. This plot is called ERPimage, and as you
>> can see in its naming, the plot is to show trial-by-trial event-related
>> phase and amplitude structure. Since your data are continuous, the function
>> determined a good number to chop up your data to make them aligned in the
>> box.
>>
>> If you see a 'column' (or 'slope') in the ERPimage that means there was
>> phase-locking event. Do you see it?
>>
>> Makoto
>>
>> 2013/3/30 ida miokovic <ida.miokovic at gmail.com>
>>
>>> Dear list,
>>>
>>> I run ICA on continuous data and now am interested into removal of the
>>> components that represent eye and muscle artifacts (and some other if
>>> recognized).
>>>  When I go through Tools --> Reject data using ICA --> Reject components
>>> by maps there is possibility for me to see Activity power spectrum, 2D
>>> location of component presence and time - trials diagram. Third mentioned
>>> diagram is shown with dimensions: 200 trials and 810 ms on y and x axis
>>> respectfully (image is in the attachment) - why exactly these values are
>>> taken? Could I change those?
>>>
>>>  Since it is IC1 that is shown, I expect it to be most likely an eye
>>> artifact, but I am confused about the look of the third diagram - it does
>>> not look like eye artifact should  and blinks are not visible as shown in
>>> EEGLAB tutorial about ICA. Am I missing somenthing? maybe it is because of
>>> only 800 ms of the dataset on x axis?
>>>
>>> Thanks
>>>
>>> Ida
>>>
>>>
>>>
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>>
>>
>>
>> --
>> Makoto Miyakoshi
>> Swartz Center for Computational Neuroscience
>> Institute for Neural Computation, University of California San Diego
>>
>
>


-- 
Makoto Miyakoshi
Swartz Center for Computational Neuroscience
Institute for Neural Computation, University of California San Diego
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