[Eeglablist] Seeking power and understanding (newtimef)

[John Johnson]

I've combed the interwebs and still haven't found a good answer.

My data has a -5s rest period followed by a 20s active period (task related
experiment, not event related). My pipeline includes rmbase(), among other
things.
Now, when I run newtimef, I can create nice plots from the ersp obtained
using:

    [ersp, itc, powbase, times, freqs, erspboot, itcboot, tfdata] = ...

        newtimef( EEG.data(channel,:,:),...

            EEG.pnts, [EEG.xmin EEG.xmax]*1000,...

            EEG.srate,...

            cycles,...

            'plotersp', 'off',...

            'plotitc', 'off',...

            'freqs', [2 25],...

            'scale', 'abs');


I just do a mean(ersp, 2) to average across time, then mean() across
subjects. The x-axis of my plot is frequency, but I don't know what the
units for the y-axis would be. I think it is percent of baseline? Now if
the values I'm seeing are percent of baseline, that means they're measured
relative to the baseline, which is redundant because I've already removed
the baseline.

If I add the 'baseline',[NaN] argument to newtimef, my plots then look like
ski slopes (high at low frequencies, low at higher frequencies).

What I would really like to have is just µV^2 so I can eventually compare,
say, C3 between conditions and see the difference. Is that possible?


I've seen this question several times on the 'net, but haven't found a good
answer.


Thanks,

John




-- 
Sent from a MacBook Pro
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://sccn.ucsd.edu/pipermail/eeglablist/attachments/20160806/284106ad/attachment.html>