[Eeglablist] reformulation previous post: getting peaks in single trials

[Bastien Boutonnet]

Dear all,  

I realised that my question was probably a bit obscure and so that it needed reformulation.  

I tried looking for a function that would pick peak amplitudes from single trials in a way where you could say pick the max (or min) value between Time-x and Time-y for each trial. I would also like if possible to preserve info about the event or at least the epoch number as I want to run a regression with peak amplitude and say RT or some continuous variable that I have for each trial. I imagine that a fairly simple script could do that but because I don’t have a great understanding of the structure of the data in MATLAB I feel like I could do with someone explaining this to me rather than try and work out a quick and dirty way to do it myself.  

Also, I am aware that such peak detection isn’t an easy thing to do on “raw” single trials and I know that there are different methods out there to clean the data out of random noise or other EEG activity which might basically hide the peaks on some occasions. People seem to do ICA or PCA transformations, filter heavily, filter using wavelets etc. I don’t yet know which one would be the best to do (and there probably isn’t a best) but this issue aside for now, there is going to be the need for me to eventually get the peaks out of the data. For this the question I ask in the previous paragraph is likely to still hold.  

If anyone has ideas or pointers as to how to do this, and if anyone has suggestions regarding methods to “clean” the single-trial data as well that would be greatly appreciated.  

Thanks for your time!  

B

—  
Bastien Boutonnet, Ph. D.
Department of Psychology
University of Wisconsin, Madison
bastienboutonnet.com

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