[Eeglablist] How to compare and analyze frequency bands ?

Makoto Miyakoshi mmiyakoshi at ucsd.edu
Mon Jul 15 11:41:56 PDT 2013


Dear Pelle,

-> how do you recommend to compare and analyze alpha bands (9-11 Hz etc.)
between datasets and/or epochs within the same dataset?

As long as you use the same recorder (same gain, same reference channel
location, etc), there should not be any problem in making comparisons for
spectra.

I saw your data. Alpha peak levels seem same, which is no good. I don't
like the 4.5 Hz peak and its harmonics in eyes open data.

Probably your data are short and noisy. Try longer recording (say 10 min)
and data cleaning (which is to manually select the dirty portions of your
data and discard them; you can do it with EEGLAB). Compute 2 or 3 SD of the
channel and compare your raw EEG against it.

Makoto



2013/7/11 Pelle Krøgholt <pellekrogholt at gmail.com>

> Hi,
>
> A fellow student and I are doing some investigations/try outs with low
> cost brain interfaces (MindWave, Epoc, OPI and possibly Muse).
>
> We are trying out eeglab for some simple frequency analysis where we
> are interested in 'the amount' of alpha with a recording either split
> in multiple datasets and or a single dataset with 2 epochs.
>
> With MindWave interface we only have one channel and have done a
> simple relaxation exercise (2 minutes w. open eyes followed by 2
> minutes w. closed eyes) - roughly we expect the last one to have more
> alpha than the first one.
>
> Which we also can see when we look of the power plots (
> http://screencast.com/t/g7JRV0iuzV ).
>
> We have looked through the fine eeglab tutorials / documentation and
> have a question:
>
> -> how do you recommend to compare and analyze alpha bands (9-11 Hz
> etc.) between datasets and/or epochs within the same dataset?
>
>
> The current script code look as follow:
>
> eeglab_analysis_eyes_mindwave.m - 2 datasets
> https://gist.github.com/pellekrogholt/5973833
> screen shoot : http://screencast.com/t/g7JRV0iuzV
>
>
> eeglab_analysis_eyes_mindwave_epochs.m - 1 dataset
> https://gist.github.com/pellekrogholt/5973877
> screen shoot : http://screencast.com/t/z59PAEMr
>
>
> Any advises are appreciated ?
>
> Pelle
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-- 
Makoto Miyakoshi
Swartz Center for Computational Neuroscience
Institute for Neural Computation, University of California San Diego
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