[Eeglablist] shifting event markers in time

[Gray, Max]

Doerte,
If I read your question correctly, I believe you want to shift your latency so the event marker (and the stimuli) occur at time zero in any subsequent single trial epochs. Therefore, I think you need to change Arno's formula to add the 50ms and not subtract it.

EEG.event(index).latency = EEG.event(index).latency+0.05*srate;

Max Gray 

-----Original Message-----
From: eeglablist-bounces at sccn.ucsd.edu [mailto:eeglablist-bounces at sccn.ucsd.edu] On Behalf Of arno
Sent: Wednesday, September 27, 2006 4:10 AM
To: doerte at spring-west.net
Cc: eeglablist at sccn.ucsd.edu
Subject: Re: [Eeglablist] shifting event markers in time


Dear Doerte,

yes, just type

for index = 1:length(EEG.event)
    EEG.event(index).latency = EEG.event(index).latency-0.05*srate;
end;
EEG = eeg_checkset(EEG, 'eventconsistency'); % check for out of bound events [ALLEEG EEG] = eeg_store(ALLEEG, EEG, CURRENTSET); % store dataset in ALLEEG eeglab redraw; % redraw GUI

Best,

Arno

Dörte Spring wrote:
> Hi folks,
>
> I was wondering whether there is a possibility in eeglab to shift all
> event markers by 50 ms backwards in time? I'm concerned that the ERPs 
> won't be right if I just create ERPs as usual and shift the revealed 
> components by 50 ms in my head for better interpretation. Namely, the 
> actual stimuli occurred 50 ms later then the event marker was sent out. 
> I really think that the baseline and its removal would yield much better 
> data/ERPs if I could include these 50 ms into the baseline as well and 
> let the ERP start 50 ms later.
>
> I'm open for any suggestions.
>
> Many thanks,
>
> Doerte
>
>   

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