[Eeglablist] File editing and epoching

[Elia Valentini]

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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