[Eeglablist] importing fMRI tr events

[Stefan Debener]

Hi Jenni,

 you need to add event labels and latencies to the EEG.event field, eg,:

evts = length(EEG.event);
EEG.event(evts+1).latency = 1234567;
EEG.event(evts+1).type = 'tr';
EEG = eeg_checkset(EEG);

You should also run eeg_checkset, which will place the new events at the 
correct index in the event field (among other things)...

However, the problem in your case is that the placement of the TR 
triggers should be as accuarte as possible. It is therefore better to 
collect the trigger by reading the TTL from the scanner while recording 
the EEG data with a high sampling rate). Even at 5 kHz sampling, a 
trigger misplaced by just one sampling point will cause problems.

Best,
Stefan



Jennifer Wilson wrote:

> Hi,
>       I'm hoping that this is an appropriate question for the list...  
> We are trying to use the FASTR function on the fMRIB plugin to remove 
> gradient artifacts from ECG data collected from subjects in a 3T 
> scanner.  I can't think of any log files that would have the timing 
> info, so I think I need to make a .txt myself (from scratch) to 
> specify the timing of each slice.  How does eeglab want this 
> information formatted though?   I couldn't find this info on the 
> tutorials online.  Or has anyone found a different method that works 
> well? 
> Thanks!
>  
> Jenni Wilson
> Cognitive Neuroscience Lab
> Department of Psychology
> Emory University
>
>------------------------------------------------------------------------
>
>_______________________________________________
>eeglablist mailing list eeglablist at sccn.ucsd.edu
>Eeglablist page: http://sccn.ucsd.edu/eeglab/eeglabmail.html
>To unsubscribe, send an empty email to eeglablist-unsubscribe at sccn.ucsd.edu
>