[Eeglablist] I: pop_spectopo specified channels, winsize and nfft

[alessandro.marassi at libero.it]

Dear Makoto,
maybe I missed something.
I need to plot single channel spectra computed in specified epochs' time ranges (baseline and task), possibly choosing winsize and nfft parameters for the spectra computation. I have then to subtract baseline spectra from task spectra.
I would like to perform this operation both in single epochs and in a set of data epochs identified by an event (StimulusBegin) and previously extracted via the EEGlab GUI menu.

As far as I know, spectopo plots the mean log spectrum of a set of data epochs, but it does not seem possible to select time ranges. It lets you choose single channels, winsize and nfft.

Pop_spectopo plots spectra of specified data channels or components. It calls spectopo().
It lets you choose time ranges, but it does not seem possible to select single channels nor to choose winsize and nfft.

If pop_spectopo is applied to the extracted epochs identified by an event (StimulusBegin), is it possible (and how) to compute spectra over a set of data epochs?
How can I practically proceed to get the result I need?
Should I modify pop_spectopo code?
Could you please give me an example script?

Thanks,
Alex

 Dear Alessandro,

> Is it possible to plot with pop_spectopo only specified channels as they
may be chosen in:
[spectra,freqs] = spectopo(EEG.data(8,:), 0, EEG.srate, 'winsize', 256,
'nfft', 512); %
possibly setting as well winsize and nfft in the same way as with the above
spectopo call?

Sure, why not?
Just be careful not to be confused with the difference between pop_spectopo
and spectopo.

Makoto


----Messaggio originale----

Da: alessandro.marassi at libero.it

Data: 02/08/2015 23.46

A: <eeglablist at sccn.ucsd.edu>

Ogg: pop_spectopo specified channels, winsize and nfft



I have to plot single channel spectra computed in specified epochs' time ranges such as:
pop_spectopo(EEG, 1, [-1000      0], 'EEG' , 'percent', 15, 'freqrange', [2 25], 'electrodes','off'

Is it possible to plot with pop_spectopo only specified channels as they may be chosen in:
[spectra,freqs] = spectopo(EEG.data(8,:), 0, EEG.srate, 'winsize', 256, 'nfft', 512); %
possibly setting as well winsize and nfft in the same way as with the above spectopo call?

As regards channels I tried to follow what has been suggested in:
http://sccn.ucsd.edu/pipermail/eeglablist/2011/004445.html
using an additional parameter " 'mapchans', 1:10 ", but without success.

thanks,
Alex 




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