freqanalysis_wltconvol.m question

Brian Roach Brian.Roach at YALE.EDU
Wed Nov 8 23:12:49 CET 2006

Thanks for your quick reply.  I did not realize that
freqanalysis_wltconvol.m allowed for 'fourier' output, but maybe I need to
download the latest version.  Or, do you mean I should use freqanalysis_mtm
instead?  Also, how does ITC differ from phase-locking value?  I thought
they were the same measure.
At 04:56 PM 11/8/2006, you wrote:
>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'
>   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
>best regards,

More information about the fieldtrip mailing list