[Eeglablist] 答复: bandwidth powers calculation over time

[Chong Li]

Dear Makoto,

Thank you for your reply.

I checked NBT, and I think NBT will be very useful for ongoing neuronal activity. Now, EEGLAB should be enough to fit my needs for offline analysis.

I am using the following codes to compute (alpha power/theta power) over the first 20s period, and then update every 2s using a 20s moving window. Could you please help me to check if it is correct?

for i= 1:6 %channel 1-6
        for j = 1:50 %I have 2 mins data, 20s moving window stops at 100s
            [power, freq] = spectopo(EEG.data(i, (2*(j-1)*128+1):(20*128+2*(j-1)*128)), 0, 128); %compute the power spectra using a 20s moving window
            pow=10.^power; %transfer db to avoid negative number
            alpha(i,j) = sum(pow(8:12))/sum(pow(1:50)); % alpha percent power of the total power
            theta(i,j) = sum(pow(4:7))/sum(pow(1:50));
            cog(i,j) = (alpha(i,j)/theta(i,j));% the ratio I need
        end
end

Thank you for your help in advance.

Best regards,
Chong
发件人: Makoto Miyakoshi [mailto:mmiyakoshi at ucsd.edu]
发送时间: 2016年4月5日 13:30
收件人: Chong Li
抄送: EEGLAB List
主题: Re: [Eeglablist] bandwidth powers calculation over time

Dear Chong,

You may want to try Simon-Shlomo Poil's NBT. Should fit your needs, I believe.
https://www.nbtwiki.net/

Makoto

On Tue, Mar 29, 2016 at 7:25 PM, Chong Li <C.Li-1 at tudelft.nl<mailto:C.Li-1 at tudelft.nl>> wrote:
Hi everyone,

I have problems in calculating (alpha power/theta power) over time. I have studied the tutorial, currently I am able to reject the artifacts using visual inspection and ICA. I can also calculate (alpha power/theta power) over channels using EEGLAB GUI. But I still have problems computing this correlation over time. Since I don't have experience in EEG analysis, any help would be appreciated.

I collected the data using EMOTIV EPOC headset. In my analysis, I would like to see the correlation between alpha and theta. To normalize the power, these bandwidth powers will be divided by total power. Then I want to calculate (alpha power/theta power) over the first 20s period, and then update every 2s using a 20s moving window.

Thanks for the help in advance.

--
Chong Li PhD student
Department of Design Engineering
Faculty of Industrial Design Engineering
Delft University of Technology
Landbergstraat 15, 2628 CE Delft, The Netherlands


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--
Makoto Miyakoshi
Swartz Center for Computational Neuroscience
Institute for Neural Computation, University of California San Diego
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