[Eeglablist] Interpolate 8 channel montage

[Delorme, Arnaud]

When there are a lot of eye blinks, and you do not want to reject all the data, you may:

1. Use clean_artifacts with loose threshold to remove only the highest amplitude artifacts (head movements etc…)

2. Use ICA to remove blinks and other eyes movements - so blinks are gone

3. Use clean_artifacts again with more agressive threshold

Best wishes,

Arno

> On Jul 30, 2020, at 9:14 AM, Makoto Miyakoshi <mmiyakoshi at ucsd.edu> wrote:
> 
> Dear Brian and Zaeem,
> 
> My first data I analyzed had only seven electrodes.
> Because these electrodes were placed symmetrically to both left-right and
> anterior-posterior axes, it was like an extremely sparse full-scalp
> recording (something like 20-40 system, instead of 10-20)
> 
> You can process such data normally except for the following points:
> 
>   - Electrode interpolation--could be very rough
>   - Average referencing--Some people say no, but I think it is fine to go
>   ahead if the electrode coverage is more or less uniform across the scalp.
>   - Dipole fitting--the result accuracy (?) is naturally limited, though
>   you tend to see smaller r.v. (why? Because less data needs to be
>   approximated)
> 
> In any case, as long as you describe these limitations clearly in your
> report, it is fine.
> 
> Makoto
> 
> 
> On Thu, Jul 23, 2020 at 8:14 AM Kavanaugh, Brian <brian_kavanaugh at brown.edu>
> wrote:
> 
>> Zaeem,
>> 
>> This is quite useful, thank you very much!
>> 
>> Brian
>> 
>> On Mon, Jul 20, 2020 at 12:17 PM Zaeem Hadi <zaeemhadi at ymail.com> wrote:
>> 
>>> Hi Brian,
>>> 
>>> I have been working with 8 channel dataset. However, I have avoided using
>>> the clean_rawdata plugin. The reason being the eye blinks, which are
>> quite
>>> high in amplitude and also present in other channels to some degree. And
>>> thus clean_rawdata would almost always reject 2 or 3 channels. And
>>> interpolating so much data on just 8 channels wouldn't make sense. But if
>>> you have relatively clean data, you might be able to use it.
>>> 
>>> To avoid that, I am using the pop_eegthresh(ALLEEG) function to
>>> semi-automatically reject epochs based on amplitude thresholding. For
>> some
>>> reason, it is not available through GUI.
>>> 
>>> That being said, I have interpolated some channels in my data due to
>>> excessive noise at the Alpha frequency range, but then I reduced the
>> number
>>> of Independent components being determined using 'pca' option in infomax
>>> ICA, as suggested by Makoto in his pre-processing pipeline.
>>> 
>>> Kind Regards,
>>> 
>>> Zaeem Hadi
>>> 
>>> Brain and Vestibular Group
>>> Imperial College London
>>> On Monday, July 20, 2020, 10:40:00 AM GMT+1, Kavanaugh, Brian <
>>> brian_kavanaugh at brown.edu> wrote:
>>> 
>>> 
>>> Hi everyone,
>>> 
>>> We are hoping to analyze a previously collected dataset that used an 8
>>> channel montage. Does anyone have any experience analyzing such a small
>>> amount of electrodes? We are specifically curious about channel
>>> interpolation options if channels are removed via clean_rawdata. Can we
>>> follow a similar approach that we use for 32/64 channel data? Thanks
>>> everyone!
>>> 
>>> Brian
>>> 
>>> --
>>> Brian Kavanaugh, PsyD.
>>> Pediatric Neuropsychologist, E. P. Bradley Hospital/Rhode Island Hospital
>>> Assistant Professor (Research), Warren Alpert Medical School of Brown
>>> University
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>> 
>> 
>> --
>> Brian Kavanaugh, PsyD.
>> Pediatric Neuropsychologist, E. P. Bradley Hospital/Rhode Island Hospital
>> Assistant Professor (Research), Warren Alpert Medical School of Brown
>> University
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