Hello,
We have an EEG experiment where participants view a film. There are flashes of light at each cut/edit in the movie, that we are using as triggers. (The flashes are edited into the bottom left corner of the movie file, and not controlled by an experiment software.) The triggers are detected by a photosensor, which is connected directly to the Active 1 receiver.
When computing ERPs, we notice sharp peaks in the baseline period. We suspect that this is because the received triggers are delayed with respect to the EEG signal. Is there a way to verify the precise time lag between EEG and triggers in this case?
Thank you!