[FieldTrip] questions itc/plf calculation via hilbert transformations
Russell G Port
russgport at gmail.com
Thu Dec 5 23:36:56 CET 2013
Hi fellow fieldtippers,
I have a question that brought around by an answer I previously received.
For data analyzed with ft_freqanalysis and using the 'wavelet' option I
can computer ITC/PLF via,
tmpdat = freq.fourierspctrm;
tmpdat = tmpdat./abs(tmpdat); ; % this will normalize each trial for its
amplitude;
itc = abs(mean(tmpdat)); % this will give the itc
thank you again Jan-Mathijs for this insight
I am now trying to calculate ITC via hilbert transformation, putting my VE
data through
ft_preproc_hilbert. Can I just use the cfg.option = 'imag', to get the
imaginary component of
the analytic signal, since this is what i use with wavelets (i.e. what the
tmpda =tmpdat./abs(tmpdat) achieves). Then I would just repeat the last
line itc =
abs(mean(tmpdat)). I only hesitate because on several of the mailing list
emails people have
suggested doing cfg.option = 'angle' (which computes the imaginary
component (tmpdat./abs(tmpdat) then uses the angle function (angle()).
Have I been calculating ITC wrong for my wavelets? Or should i just the the
cfg.option = 'imag' and mimik my wavelet based ITC.
Thanks
Russ
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