[Eeglablist] newtimef with large frequency windows

[Bradley Voytek]

Zach:

Your decomposition parameters require a 558 ms windows on either side
of your epoch, so if you want a 200 ms baseline you'll have to have a
minimun time of your epoch be (200 + 558) = 758 ms. Your ending time
of 1000ms should be sufficient for the timing of the ERP components of
interest.

That said, with such a large pass band, why not just band pass your
raw signal between 3 and 60 Hz? Why bother with a time-frequency
decomposition?

::brad


On Sat, Aug 9, 2008 at 2:57 PM, Zachary Moran <zdmoran at gmail.com> wrote:
> Hi all,
>
>
> At the moment I'm working on a project in which I'm trying to get ERSP
> estimates around some early evoked potentials (e.g., between 20 and 100
> ms).  Though I'd like to implement a frequency window of 3 to 60 Hz, when I
> attempt to do so, EEGLAB forces the output to fall within a window of 358.0
> to 442.0 ms.  Unfortunately, the only way I'm able to get to earlier
> time-points is to increase my minimum frequency to around 12 Hz thus
> allowing for an overall larger time window.  However, I have seen the sort
> of analysis that I'm looking for done (I think in EEGLAB, since it used ERSP
> and ITC specifically) by Brockhaus-Dumke et al. (2008)  "Sensory gating
> revisited: Relation between brain oscillations and auditory evoked
> potentials in schizophrenia."  I've included an example of my script below:
>
> <<figure; pop_newtimef( EEG, 1, 1, [-200  1000], [3         0.5] ,'type',
> 'phasecoher', 'topovec', 1, 'elocs', EEG.chanlocs, 'chaninfo', EEG.chaninfo,
> 'title','ERSP and ITC','padratio', 1, 'plotphase','off','freqs',[3 60]);>>
>
> My dataset is sampled at 1000 Hz and has 1201 frames per epoch.  Does anyone
> have any experience with this who knows how I might get around this problem
> or any way of recentering the output window around desired ERP components
> (e.g., from 75 to 125)?  Any help or information would be very greatly
> appreciated.
>
>
> Thank you very much,
>
>
> Zach
>
>
> Zachary Moran
> Graduate Student
> University of California-Los Angeles
>
> _______________________________________________
> Eeglablist page: http://sccn.ucsd.edu/eeglab/eeglabmail.html
> To unsubscribe, send an empty email to eeglablist-unsubscribe at sccn.ucsd.edu
> For digest mode, send an email with the subject "set digest mime" to
> eeglablist-request at sccn.ucsd.edu
>