freqanalysis_wltconvol.m question

[Robert Oostenveld]

Hi Brian

On 8 Nov 2006, at 21:20, Brian Roach wrote:
> eI would like to take this complex output and use it to calculate
> phase-locking factor, but I am not sure what parts of the power
> transformation need to be removed - just the abs() and the
> squaring?  Clarification of this line of code would be extremely
> helpful to me.

You can use the existing code for that:

For computing the phase-locking value I suggest that you use either
   cfg.output='fourier'
   cfg.keeptrials='yes'
   cfg.keeptapers='yes'
or
   cfg.output='fourier'
   cfg.keeptrials='yes'
   cfg.keeptapers='no' (not needed now)
   cfg.channelcmb = something, see the help
in freqanalysis.

Subsequently, use the option
   cfg.cohmethod='plv'
in freqdescriptives. In case of fourier output in freqanalysis, you
should specify the channel combinations here.

...
Looking back at your previous mail, I see that you mean ITC and not
PLV. The stuff above then does not apply. You can do output=fourier
in freqanalysis and work manually on the output freq structure. I
think that this should work

magnitude = abs(freq.fourierspctrm);
scaled    = freq.fourierspctrm ./ magnitude;
freq.itcspctrm = mean(scaled, 1);
freq = rmfield(freq, 'fourierspctrm');   % remove the single
fourierspectrum, to avoid confusion
freq.dimord = 'chan_freq_time';          % remove the rpt or rpttap
dimension

best regards,
Robert