[Eeglablist] Calculation of each frequency band's power density?

[Tarik S Bel-Bahar]

This might be of use to you.
Check the output variables when running spectopo,
you should be able to tell which output variable (in your Matlab workspace)
holds the spectral values. You should then
be able to take the average of a set of columns or rows
that contain your data of interest.
For basic questions about matlab,
ask Google questions such as "Take average of a row of numbers MATLAB" ,
etc....
which will take you directly to Mathworks and other tutorials.
Basically any question you have, you can find some initial answer,
especially for basic work such as averaging a set of numbers.

http://sccn.ucsd.edu/eeglab/allfunctions/spectopo.html

*SPECTOPO*Plot the mean log spectrum of a set of data epochs at all
channels as a bundle of traces. At specified frequencies, plot the relative
topographic distribution of power. If available, uses pwelch() from the
Matlab signal processing toolbox, else the EEGLAB
spec<http://sccn.ucsd.edu/eeglab/allfunctions/spectopo.html> function.
Plots the mean spectrum for all of the supplied data, not just the
pre-stimulus baseline.
*Usage:*>> spectopo(data, frames, srate);
>> [spectra,freqs,speccomp,contrib,specstd] = spectopo(data, frames, srate,
'key1','val1', 'key2','val2' ...);

On Thu, May 10, 2012 at 8:37 AM, Chen, Meixuan <mc155 at hw.ac.uk> wrote:

>  Hi, I have a question on how to calculate the power spectrum density of
> each frequency band, such as Alpha band frequency from 8-13Hz? I use EEGLab
> to plot the whole power spectrum on each channel with no problem, but when
> I want to look at the activity of each frenqucy band at different channels
> and under different conditions by comparing their power density, I don't
> know how to calculate the frequency band power on EEGLab, which is the
> whole frequency range power instead the power of certain frequency like
> 10Hz. From reviewing other people's works, I guess that I may need to
> integrate in the frequency band's power on Matlab. I am not very good at
> Matlab, still haven't solved out how to do it.  Could anyone please give me
> some advice?
>
> Many thanks.
>
> Regards
>
>  Michelle Chen
> Heriot-Watt University
> Tel +44(0)1896 892268
> mc155 at hw.ac.uk
>
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