[Eeglablist] A question about extracting single trial EEG data

[Cedric Cannard]

Hi Song,

If I understand correctly, and assuming you have already epoched your data for each condition. Here is an example to get the average ERP across trials for the latencies 100-300 ms post-stimulus:

lats = [100 300];  % edit with your latency bounds of interest (in ms)

idx = EEG.times>=lats(1) & EEG.times<=lats(2);
ERP = squeeze(mean(EEG.data(:,idx,:),3));  % idx keeps only the window of interest, and mean on 3rd dimension averages across trials

Or if you haven't epoched your data yet, you can do so like this (from -300 ms to + 1000 ms):
EEG = pop_epoch(EEG, {'condition1' 'condition2'}, [-.3 1.5]);

Note that conditions here correspond to your event markers.

Hope this helps,

Cedric Cannard




Cedric



On Tuesday, March 26th, 2024 at 3:08 PM, 宋庆一 via eeglablist <eeglablist at sccn.ucsd.edu> wrote:

> Hi~
> 
> 
> I am currently working on single trial analysis, but I don't know how to extract single trial EEG data (actually what I want is ERP data, i.e. the averange of certain time window). I would really appreciate it if someone could help me.
> 
> 
> Sincerely,
> Song
> 
> 
> 
> 
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