[Eeglablist] File editing and epoching

[Tarik S Bel-Bahar]

Hi Ella,

Just a few quick comments, hope these comments help, good luck with the
process, and let the list know of your success.

1. if boundaries are added because of rejection of artifactual periods, you
probably want to keep them in.
If you are trying to get all the epochs out, and then you will reject some
of them, then see point #2.

2. If you use the "cleaned" data with "extra boundaries due to cleaning" to
generate ICA,
then you should then apply the IC weights to your pre-ICA continuous data
(as long it has the same number of channels as the file that went into the
ICA)

2.5. see some recent discussions on the list on topics of ICA and cleaning
( in the last month).

3. In your step #5 I assume you mean remove baseline of all channels, for
continuous data.

4. keep in mind that you don't have to reject components if you focus on
analyzing the ICs.

5. adding markers/labels can be automated by simple scripts.

6. Some of your points are not exactly clear, but, it seems you are going
in the right direction.
Most of what you believe can be automated can very certainly easily be
automated by script.

Let the list know with followup specific questions when you are ready. Be
sure to provide good details
so that helpers can best understand what you need and what you are trying
to do.










































On Mon, Oct 1, 2012 at 12:59 PM, Elia Valentini
<elia.valentini at uniroma1.it>wrote:

> Dear EEGlabers,
>
> I'm looking for the expert list help on some difficulties I'm having on
> adding and deleting markers to my data files, and baseline correcting
> epoched data.
>
> As a premise our design implies:
> a) two different set of files where a different cognitive manipulation is
> administered (factor 'mind-set')
> b) two different type of blocks, pre-post manipulation (factor
> 'manipulation')
>
> within each block we have two different sensory modalities delivered in
> pairs - S1,S2 - (we are interested in studying ERPs).
>
> I did the following:
> 1) Marge all the single subject datasets (4 neuroscan .cnt files per
> session).
> 2) Downsample to 250 Hz (originally 1000 Hz).
> 2) Re-reference to the average (excluding mastoid and EOG electrodes).
> 3) Bandpass filter 0.5-30 Hz.
> 4) Manually reject gross artifacts from the continuous large datafile
> 5) Remove baseline and run ICA
> 6) Reject components by maps
>
> I'm in the process of
> 7) Removing "boundary markers" produced by the manual rejection procedure
> (deleted one by one from the "Event values" interface. I guess this could
> be automated but I'm doing it manually).
> 8) Add markers (or rather labels as this are not phasic EEG events) for
> the levels of the variable 'mind-set' and 'manipulation' (I guess this
> could be automated but I'm doing it manually).
> 9) Then I need to generate epoched files from this large file according to
> the two modalities and locked to the first stimulus of each couple.
> However, while the first stimulus is baseline corrected to its relative
> pre-stimulus time, the second stimulus (S2) should be baseline corrected to
> the S1 prestimulus time (I did not come out yet with a scripting of it -  I
> guess may not be possible from the GUI).
>
> Perhaps I have missed some important past discussion in the list, if this
> is the case please forgive me.
> Thanks very much in advance for your time.
>
> Elia
>
>
>
>
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