[Eeglablist] Could ICA for clean-up be done within STUDY?

[Makoto Miyakoshi]

Dear Akshay,

When creating STUDY, you can select an (almost default) option to 1) kick
out ICs whose dipole locations are outside the brain, 2) reject ICs whose
dipole residual variance is > 15%. This will usually reject up to 70% of
ICs, which is a good cleaning.

By the way rejecting 70% of ICs does not mean you reject 70% of data, since
each IC has different weights on the channel EEG. ICs are sorted by the
order of the variance it accounts for. For example, if you have 128
channels and 128 ICs, maybe top 20 ICs would count more than 80% of the raw
data. In this case, rejecting the remaining 108 ICs means to reject 20% of
data in variance. 1st IC could have more than 100 times variance than the
128th IC.

Makoto

On Sat, Oct 31, 2015 at 5:14 AM, Akshay Maggu <akshaymaggu86 at gmail.com>
wrote:

> Hi all,
>
> Wanted to know if the sample data for STUDY available at
> ftp://sccn.ucsd.edu/pub/5subjects_full.zip consists of data after removal
> of non-neurophysiological ICs (from each subject)?
>
> In short, is it recommended to clean-up data for each subject using ICA,
> before putting in STUDY or could it also be done within STUDY?
>
> Thanks in advance,
> Akshay
> --
> Akshay Raj Maggu,
> PhD Candidate,
> Laboratory for Language, Learning and the Brain,
> Department of Linguistics and Modern Languages,
> The Chinese University of Hong Kong,
> Hong Kong.
> Webpage: http://www.cuhk.edu.hk/lin/new/people/students/maggu/
> *Save trees.. Save life! Please don't print this email unless you really
> need to.....*
>
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-- 
Makoto Miyakoshi
Swartz Center for Computational Neuroscience
Institute for Neural Computation, University of California San Diego
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