[Eeglablist] changing the epoch duration

[James Desjardins]

Hi Jeffrey,

To do this you can use the menu option "Edit > Select data" then enter  
your time values in the edit box beside "Time range [min max] (s)".  
For example entering [-.2 .8] will reduce your segments to a one  
second epoch starting at -200ms relative to your lock event.

Similarly you could call the following from the command line or script:

EEG = pop_select(EEG,'time',[-.2 .8]);


As a side note, I am interested to know if there are any side effects  
of using large overlapping segments for ICA due to temporally  
redundant data? To avoid performing the ICA on redundant time points I  
have been running it on the pruned continuous signal before segmenting.

James Desjardins
Technician, MA Student
Department of Psychology, Behavioural Neuroscience
Cognitive and Affective Neuroscience Lab
Brock University
500 Glenridge Ave.
St. Catharines, ON, Canada
L2S 3A1
905-688-5550 x4676


Quoting "Cockburn, Jeffrey" <jeffrey_cockburn at brown.edu>:

> Greetings.
>
> I like to take long epoch durations to give ICA a little more data to work
> with (about 5 seconds from start to finish surrounding my events of
> interest). After running ICA and extracting the components I need, I would
> like to reduce the epoch duration around the events of interest (about 1
> second from start to finish). I can't use the 'extract epochs' function
> because this produces duplicate events since the original 5 second epoch
> window captures more than one event of interest in each epoch. I've also
> tried manually reshaping EEG.data and EEG.times, but this seems to confuse
> EEGlab as to when events occur in relation to the raw EEG data. Is there an
> easier way to do this?
>
> Thanks
>