Signal averaging to detect Evoked potentials ?

Hello,

I understand the logic behind this concept, but I do not understand the theory and implementation in MATLAB. It is quite clear that in order to detect the Event-related potentials from EEG, the signal has to be stimulus-locked and averaged over trials (to eliminate the background noise), but how to do this time-locking and averaging?

Take for example, I have a 10 msec stimulus with 0.5 HZ repetition frequency. The EEG is acquired from two channels. in which way should I cut the recordings into trials and do the averaging (what is the implementation of this averaging in MATLAB, just applying mean() function?). I know about the Toolboxes like EEGLAB etc; however I would like to understand this intuitively. SO I really appreciate if someone can explain this in plain English with a simple MATLAB code.

Thanks

[mosa mm]

Seriously! no one knows ? lol

[Piotr Tabor]

Hello, have you found a solution on how to do averaging of a EP signal without measuring when the trigger appeared?

Answer 1

[VNC]

Hi there, I think what you are looking for is called a peri-stimulus time histogram (PSTH), that averages all your stimuli (let's say you applied 100 times your stimulus), then this will be averaged and then will plot you the average evoked potentials for example.

You can find more documented here: PSTH (this is for spikes)

Hope this helps.

[Anwesha]

Hi Mosa, Di you find a way to do this. Dis you have to subtract the evoked response from the baseline? I appreciate your reply