# [Eeglablist] Comparing mu suppression with EEGLAB

Anderson Oliveira asoliv at umich.edu
Wed Jun 25 07:20:22 PDT 2014

```Hi, I have a question concerning the proposed code, since I'm not very
familiar with EEGLAB so far:

Why in the command below channel 1 is represented by the number 2?   if the
matrix EEG.data has 64 channels for instance, does the code starts on the 2
position in the first dimension?

% for your epoched data, channel 1
[spectra,freqs] = spectopo(EEG.data(2,:,:), 0, EEG.srate);

Thanks for the help,
Anderson

On Mon, Jun 23, 2014 at 1:15 PM, Makoto Miyakoshi <mmiyakoshi at ucsd.edu>
wrote:

> Dear Florient,
>
> Maybe this code can help you. Good luck.
>
> I've seen quite a few users wanted to know how to do this. Maybe it would
> be convenient if I write a simple EEGLAB plugin for this.
>
> Makoto
>
> % for your epoched data, channel 1
> [spectra,freqs] = spectopo(EEG.data(2,:,:), 0, EEG.srate);
>
> % delta=1-4, theta=4-8, alpha=8-13, beta=13-30, gamma=30-80
> deltaIdx = find(freqs>1 & freqs<4);
> thetaIdx = find(freqs>4 & freqs<8);
> alphaIdx = find(freqs>8 & freqs<13);
> betaIdx  = find(freqs>13 & freqs<30);
> gammaIdx = find(freqs>30 & freqs<80);
>
> % compute absolute power
> deltaPower = 10^(mean(spectra(deltaIdx))/10);
> thetaPower = 10^(mean(spectra(thetaIdx))/10);
> alphaPower = 10^(mean(spectra(alphaIdx))/10);
> betaPower  = 10^(mean(spectra(betaIdx))/10);
> gammaPower = 10^(mean(spectra(gammaIdx))/10);
>
>
> On Thu, Jun 19, 2014 at 2:30 AM, CHOUTEAU Florient <
> florient.chouteau at isae.fr> wrote:
>
>>  Hi,
>> I am an human factor students doing a research projet on mirror neurons
>> and I am struggling with EEGLAB.
>> I am trying to compare several EEG signals, mainly located in C3/C4 using
>> more or less the same protocol as Oberman et al 2007[1] and 2005[3]. In
>> fact, I acquired three signals (subject presented to three videos including
>> a baseline (white noise)) and I am trying to calculate mu suppression by
>> displaying "The ratio of the power in the mu frequency" as described in
>> [1], [2] and [3]. (Specific quote: "For each cleaned segment the integrated
>> power in the 8–13 Hz range was computed using a fast Fourier transform")
>> Problem is, I have absolutely no clue as to how "substract" the power
>> from the two tests and the baseline in EEGLAB. I successfully displayed the
>> power = f (frequency) for all of my signals but substracting one to the
>> other and calculating the global power in the frequency range remain a
>> mystery to me.
>>
>> Assuming that I dispose of cleaned epoched data, would you have any idea
>> as to how to proceed, using EEGLAB functions or simply MATLAB ones,
>>
>> Best Regards,
>>
>> Florient CHOUTEAU
>>
>> References:
>>
>> [1]Oberman, L. M., McCleery, J. P., Ramachandran, V. S., & Pineda, J. A.
>> (2007). EEG evidence for mirror neuron activity during the observation of
>> human and robot actions: Toward an analysis of the human qualities of
>> interactive robots. *Neurocomputing*, *70*(13), 2194-2203.
>>
>> http://cognitiveneurolab.ucsd.edu/Papers_files/Oberman,%20L.M.,%20McCleery,%20J.P.,%20Ramachandran,%20V.S.,%20and%20Pineda,%20J.A.%C2%A0%20EEG%20evidence%20for%20mirror%20neuron%20activity%20during%20the%20observation%20of%20human%20and%20robot%20actions_2.pdf
>>
>> [2]Arnstein, D., Cui, F., Keysers, C., Maurits, N. M., & Gazzola, V.
>> (2011). μ-suppression during action observation and execution correlates
>> with BOLD in dorsal premotor, inferior parietal, and SI cortices. *The
>> Journal of Neuroscience*, *31*(40), 14243-14249.
>> http://www.jneurosci.org/content/31/40/14243.full
>>
>> [3]Oberman, L. M., Hubbard, E. M., McCleery, J. P., Altschuler, E. L.,
>> Ramachandran, V. S., & Pineda, J. A. (2005). EEG evidence for mirror neuron
>> dysfunction in autism spectrum disorders. *Cognitive Brain Research*,
>> *24*(2), 190-198.
>> http://www.bowdiges.org/documents/files/Mirror_neurons_in_ASD.pdf
>>
>>
>>
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>
>
>
> --
> Makoto Miyakoshi
> Swartz Center for Computational Neuroscience
> Institute for Neural Computation, University of California San Diego
>
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