[Eeglablist] Separate the data into suitable short data epochs ?

[Arnaud Delorme]

>somehow I got disconnected from the ICA list and could not find the threads on the web.
>so here I might ask a question that has been answered many times.
>  
>
The threads have currently been temporarilly removed because spamming 
robots were surfing them to find email adresses. We will modify the 
email adresses of the participants (probably by replacing @ with "at") 
and put it back online soon.

>For getting artifacts out of continuous data you recommend
>2. Separate the data into suitable short data epochs.
>
>I have a data set of 5 minutes. What do you mean by suitable?
>  
>
For getting artifacts out from continuous data, you may run ICA on the 
continuous data itself:
1) remove bad portions of data (paroxismic activity, large head 
movements...)
2) lowpass the data (less than 0.5 Hz) to remove linear trends that 
would dramatically affect the ICA decomposition
3) apply ICA
4) select artifactual components

>Does EEGLAB provide a chopping function or do I do the chopping in matlab?
>  
>
If you want to epoch your continuous data, you need to create events. 
For instance, if you want to have events every second for the first 40 
seconds, simply create this array

me =  [ones(40,1) [1:40]'];

and import it using the menu "File > Import event info > From Matlab 
array or ASCII file" (first column "type" and second one "latency").
Best

Arno


>Best,
>Johannes
>
>
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-- 

*Arnaud Delorme, Ph.D.*
Computational Neurobiology Lab, Salk Institute
10010 North Torrey Pines Road
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*Tel* : /(+1)-858-458-1927 ext 15/
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        /PRINPRSU - from the Diamond Sutra/  

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