[Eeglablist] Marking and Extracting continous portions of data after epoching

[Makoto Miyakoshi]

Dear Lucia,

I did not understand why continuous data rejection does not work for you.
My comment below may not be specific to your case.

You can clean it with clean_rawdata() that uses Artifact Subspace
Reconstruction (ASR). You can install it from EEGLAB plugin manager or from
here
http://sccn.ucsd.edu/wiki/Plugin_list_process

> Another potential way is to re-lable the event markers such that the ones
in each block are different - does anyone know of a way I can selectively
re-label event markers? (i.e. turn all the event markers '4' from the first
block only to '44')?

You can do it from EEGLAB GUI 'Edit'... if you can write a Matlab code, you
want to write either a for loop to replace them. I saw the related post
just a few days ago. Go to eeglablist archive and find it by title.

Makoto

On Wed, Feb 11, 2015 at 7:39 AM, Li, Lucia M <lucia.li at imperial.ac.uk>
wrote:

>  Dear eeglab users & experts,
>
>  Would someone be able to help me out with a query?
>
>  I am analysing EEG data from a task. This task is separated into 3
> blocks (beginning, middle and last), and there are several trials within
> each block. I would like to compare EEG parameters between the trials
> occurring in different blocks. I know that I can highlight continuous
> portions of data for rejection (e.g. reject the middle and last portions,
> and be left with just the beginning portion). However, I don't want to do
> this because I think that subsequent cleaning on the divided data may
> introduce bias - i.e. differences between the blocks may be because of
> differences in cleaning and not due to differences in neurological state.
>
>  I have tried a couple of different methods (e.g. adding markers in, but
> eeglab doesn't seem to allow bins of different sizes to exist; trying to
> use Edit --> select data using events, but after cleaning and deleting
> noisy epochs the markers may be deleted). The stimulus markers do not
> differentiate between each block.
>
>  Another potential way is to re-lable the event markers such that the
> ones in each block are different - does anyone know of a way I can
> selectively re-label event markers? (i.e. turn all the event markers '4'
> from the first block only to '44')?
>
>  Does anyone have any other suggestions for how I can mark divide my data
> (after epoching and cleaning) into the blocks?
>
>  Thank you in advance for your help.
>
>  Kind regards,
> Lucia
>
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-- 
Makoto Miyakoshi
Swartz Center for Computational Neuroscience
Institute for Neural Computation, University of California San Diego
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